pretty print tracer: Use argument vector visitor master
authorMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Thu, 16 May 2024 19:26:56 +0000 (15:26 -0400)
committerMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Thu, 16 May 2024 19:26:56 +0000 (15:26 -0400)
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Makefile.am
configure.ac
doc/Makefile.am [new file with mode: 0644]
doc/rfc-side-abi.txt [new file with mode: 0644]
src/Makefile.am
src/smp.c
src/tracer.c
src/visit-arg-vec.c [new file with mode: 0644]
src/visit-arg-vec.h [new file with mode: 0644]

index fab5179292a87a82ccfaf0c834cbd58b9acafbf2..5acd61319802b256e291f7f65c2e83664afb241f 100644 (file)
@@ -4,6 +4,7 @@
 ACLOCAL_AMFLAGS = -I m4
 
 SUBDIRS = \
+       doc \
        include \
        src \
        tests
index 6142c90d39e071d4c6c967bf499b42826fe59225..d72eb04a19b04e5ce6caacaa3e0e9421ffe1278a 100644 (file)
@@ -204,6 +204,7 @@ AC_SUBST(AM_CXXFLAGS)
 
 AC_CONFIG_FILES([
        Makefile
+       doc/Makefile
        include/Makefile
        src/Makefile
        src/libside.pc
diff --git a/doc/Makefile.am b/doc/Makefile.am
new file mode 100644 (file)
index 0000000..9cf770a
--- /dev/null
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: MIT
+# SPDX-FileCopyrightText: 2024 EfficiOS Inc.
+
+EXTRA_DIST = rfc-side-abi.txt
+dist_doc_DATA = rfc-side-abi.txt
diff --git a/doc/rfc-side-abi.txt b/doc/rfc-side-abi.txt
new file mode 100644 (file)
index 0000000..8476672
--- /dev/null
@@ -0,0 +1,222 @@
+
+RFC - SIDE ABI
+
+[ This document is under heavy construction. Please beware of the
+  potholes as you wander through it. ]
+
+* Introduction
+
+The purpose of the SIDE ABI is to allow kernel and user-space tracers to
+attach to static and dynamic instrumentation of user-space applications.
+
+The SIDE ABI expresses the instrumentation description as data (no
+generated code). Instrumentation arguments are passed on the stack as an
+array of typed items, along with a reference to the instrumentation
+description.
+
+The following ABIs are introduced to let applications declare their
+instrumentation and insert instrumentation calls:
+
+- an event description ABI,
+- a type description ABI,
+- an event and type attribute ABI, which allows associating key-value
+  tuples to events and types,
+- an ABI defining how applications provide arguments to instrumentation
+  calls.
+
+The combination of the type description and type argument ABIs is later
+refered to as the SIDE type system.
+
+The ABI exposed to kernel and user-space tracers allow them to list
+and connect to the instrumentation, and conditionally enables
+instrumentation when at least one tracer is using it.
+
+The type description and type argument ABIs include support for
+statically known types and dynamic types. Nested structures, arrays, and
+variable-length arrays are supported.
+
+The libside C API is a reference implementation of the SIDE ABI for
+instrumentation of C/C++ applications by user-space tracers following
+the default calling convention (System V ELF ABI on Linux, MS ABI on
+Windows) and eventually by Linux kernel tracers through the User Events
+ABI.
+
+A set of macros is provided with the libside C API for convenience of
+C/C++ application instrumentation.
+
+
+* Genesis
+
+The SIDE ABI and libside library learn from the user feedback about
+experience with LTTng-UST and Linux kernel tracepoints, and therefore
+they introduce significant changes (and vast simplifications) to the way
+instrumentation is done compared to LTTng-UST and Linux kernel
+tracepoints.
+
+- Linux kernel User Events ABI
+  - Exposes a stable ABI allowing applications to register their event
+    names/field types to the kernel,
+  - Can be expected to have a large effect on application instrumentation,
+  - My concerns:
+    – Should be co-designed with a userspace instrumentation API/ABI rather than only
+      focusing on the kernel ABI,
+    – Should allow purely userspace tracers to use the same instrumentation as userspace
+      tracers implemented within the Linux kernel,
+    – Tracers can target their specific use-cases, but infrastructure should be shared,
+    – Limit fragmentation of the instrumentation ecosystem.
+
+- Improvements over tracepoints:
+  - Improve compiler error reporting vs tracepoints
+  - API uses standard header inclusion practices
+  - share ABI across runtimes (no need to reimplement tracepoints for
+    each language, or to use string only payloads)
+
+- Improvements over SDT: allow expressing additional event semantic
+  (e.g.  user attributes, versioning, nested and compound data types)
+  - libside has less impact on control flow when disabled (no stack setup)
+  - SDT ABI is focused on architecture calling conventions, libside ABI
+    is easier to use from runtime environments which have an ABI
+    different from the native architecture (golang, rust, python, java).
+    libside instrumentation ABI calls a small fixed set of functions.
+
+- Comparison with ETW
+  - similar to libside in terms of array of arguments,
+  - does not support pre-registration of events (static typing)
+    - type information received at runtime from the instrumentation
+      callsite.
+
+
+* Desiderata
+
+- Common instrumentation for kernel and purely userspace tracers,
+  - Instrumentation is self-described,
+  - Support compound and nested types,
+  - Support pre-registration of events,
+  - Do not rely on compiled event-specific code,
+  - Independent from ELF,
+  - Simple ABI for instrumented code, kernel, and user-space tracers,
+  - Support concurrent tracers,
+  - Expose API to allow dynamic instrumentation libraries to register
+    their events/payloads.
+
+- Support statically typed instrumentation
+
+- Support dynamically typed instrumentation
+  - Natively cover dynamically-typed languages
+  - The support for events with dynamic fields allows lessening the number
+    of statically declared events in situation where an application
+    possesses seldom-used events with a large variety of parameter types.
+  - The support for mixed static and dynamic event fields allows
+    implementation of post-processing string formatting along with a
+    variadic payload, while keeping trace data in a structured format.
+
+- Performance considerations for userspace tracers.
+  - Maintain performance characteristics comparable to existing
+    userspace tracers.
+  - Low overhead, good scalability when used by userspace tracers.
+
+- Allows tracing user-space through a kernel tracer. Even through it is
+  an approach that adds more overhead, it has the benefit of not
+  requiring agent threads to be deployed into applications, which is
+  useful to trace locked-down processes.
+
+- Instrumentation registration APIs
+  - Instrumentation can be generated at runtime
+    - dynamic patching,
+    - JIT
+  - Instrumentation can be declared statically (static instrumentation)
+  - Instrumentation can be enabled dynamically.
+    - Very low overhead when not in use.
+
+- libside must be extensible in the future.
+  - Extension scheme should allow adding new types in the future without
+    requiring complex logic to future-proof tracers.
+  - Exposed types are invariant,
+  - libside ABI and API can be extended by adding new types.
+
+- the side ABI should allow multiple instances and versions within
+  a process (e.g. libside for C/C++, Java side ABI, Python side ABI...).
+
+- Both event description and payload are data (no generated text).
+  - It allows tracers to directly interpret the event payload from their
+    description, removing the need for code generation. This lessens the
+    instruction cache pollution compared to code generation approaches.
+  - Tracer interpreter for filtering and field capture can directly use
+    the instrumentation data, without need for setting up a structured
+    argument layout on the stack within the tracer.
+
+- Validation of argument vs event description coherence.
+
+- Passing arguments to events should be:
+  - Conveniently express application data structures to be expected as
+    instrumentation input.
+  - Flexible,
+  - Efficient,
+  - If all are not possible combined, specialize types for each purpose.
+
+- Allow tracers to passively collect application state transitions.
+
+- Allow tracers to actively sample the current state of an application.
+
+- Error messages generated when misusing the API should be easy to
+  comprehend and resolve.
+
+- Allow expressing additional custom semantic augmenting events and
+  types.
+
+
+* Design / Architecture
+
+- Compiler error messages are easy to understand because it is a simple
+  header file without any repeated inclusion tricks.
+
+- Variadic events.
+
+- Instrumentation API/ABI:
+  – Type system,
+    - Type visitor callbacks
+      - (perfetto)
+    - Stack-copy types
+    - Data-gathering types
+    - Dynamic types.
+  – Helper macros for C/C++,
+  – Express instrumentation description as data,
+  – Instrumentation arguments are passed on the stack as a data array
+    (similar to iovec) along with a reference to instrumentation
+    description,
+  – Instrumentation is conditionally enabled when at least one tracer is
+    registered to it.
+
+- Tracer-agnostic API/ABI:
+  – Available events notifications,
+  – Conditionally enabling instrumentation,
+  – Synchronize registered user-space tracer callbacks with RCU,
+  – Co-designed to interact with User Events.
+
+- Application state dump
+  - How are applications/libraries meant to provide state information ?
+  - How are tracers meant to interact with state dump ?
+  - statedump mode polling
+  - statedump mode agent thread
+
+- RCU to synchronize userspace tracers registration vs invocation
+
+- How tracers are meant to interact with libside ?
+
+- How is C/C++ language instrumentation is meant to be used ?
+
+- How are dynamic instrumentation facilities meant to interact with
+  libside ?
+
+- How is a kernel tracer meant to interact with libside ?
+
+- How is gdb (ptrace) meant to interact with libside ?
+
+- Validation that instrumentation arguments match event description
+  fields cannot be done by the compiler, requires either:
+  - run time check,
+  - static checker (only for static instrumentation).
+
+- Event attributes.
+
+- Type attributes.
index be3f863d1043172739fe3eee1bdab05ab087f52b..bf58380ef0f421060c2b3f85ed1fe564a59ff9c8 100644 (file)
@@ -22,7 +22,9 @@ libside_la_SOURCES = \
        list.h \
        rculist.h \
        side.c \
-       tracer.c
+       tracer.c \
+       visit-arg-vec.c \
+       visit-arg-vec.h
 
 libside_la_LDFLAGS = -no-undefined -version-info $(SIDE_LIBRARY_VERSION)
 libside_la_LIBADD = \
index 9788e93198e4433ebb12933f0e96a01025706d6f..60f69ac9a439810a2b1d7052308ca2a015bbc1d5 100644 (file)
--- a/src/smp.c
+++ b/src/smp.c
@@ -157,7 +157,7 @@ int get_cpu_mask_from_sysfs(char *buf, size_t max_bytes, const char *path)
 
                total_bytes_read += bytes_read;
                assert(total_bytes_read <= max_bytes);
-       } while (max_bytes > total_bytes_read && bytes_read > 0);
+       } while (max_bytes > total_bytes_read && bytes_read != 0);
 
        /*
         * Make sure the mask read is a null terminated string.
index 1973c4cedeb39f0e669ed2a9de77af6c18c14e49..a10dded6fa827a92cad900cd7728aaffee0550eb 100644 (file)
 
 #include <side/trace.h>
 
+#include "visit-arg-vec.h"
+
+/* TODO: optionally print caller address. */
+static bool print_caller = false;
+
+#define MAX_NESTING    32
+
 enum tracer_display_base {
        TRACER_DISPLAY_BASE_2,
        TRACER_DISPLAY_BASE_8,
@@ -25,51 +32,21 @@ union int_value {
        int64_t s[NR_SIDE_INTEGER128_SPLIT];
 };
 
+struct print_ctx {
+       int nesting;                    /* Keep track of nesting, useful for tabulations. */
+       int item_nr[MAX_NESTING];       /* Item number in current nesting level, useful for comma-separated lists. */
+};
+
 static struct side_tracer_handle *tracer_handle;
 
 static uint64_t tracer_key;
 
-static
-void tracer_print_struct(const struct side_type *type_desc, const struct side_arg_vec *side_arg_vec);
-static
-void tracer_print_variant(const struct side_type *type_desc, const struct side_arg_variant *side_arg_variant);
-static
-void tracer_print_array(const struct side_type *type_desc, const struct side_arg_vec *side_arg_vec);
-static
-void tracer_print_vla(const struct side_type *type_desc, const struct side_arg_vec *side_arg_vec);
-static
-void tracer_print_vla_visitor(const struct side_type *type_desc, struct side_arg_vla_visitor *vla_visitor);
-static
-void tracer_print_dynamic(const struct side_arg *dynamic_item);
-static
-uint32_t tracer_print_gather_bool_type(const struct side_type_gather *type_gather, const void *_ptr);
-static
-uint32_t tracer_print_gather_byte_type(const struct side_type_gather *type_gather, const void *_ptr);
-static
-uint32_t tracer_print_gather_integer_type(const struct side_type_gather *type_gather, const void *_ptr,
-               enum tracer_display_base default_base);
-static
-uint32_t tracer_print_gather_float_type(const struct side_type_gather *type_gather, const void *_ptr);
-static
-uint32_t tracer_print_gather_string_type(const struct side_type_gather *type_gather, const void *_ptr);
-static
-uint32_t tracer_print_gather_enum_type(const struct side_type_gather *type_gather, const void *_ptr);
-static
-uint32_t tracer_print_gather_struct(const struct side_type_gather *type_gather, const void *_ptr);
-static
-uint32_t tracer_print_gather_array(const struct side_type_gather *type_gather, const void *_ptr);
-static
-uint32_t tracer_print_gather_vla(const struct side_type_gather *type_gather, const void *_ptr,
-               const void *_length_ptr);
-static
-void tracer_print_type(const struct side_type *type_desc, const struct side_arg *item);
-
 static
 void tracer_convert_string_to_utf8(const void *p, uint8_t unit_size, enum side_type_label_byte_order byte_order,
                size_t *strlen_with_null,
                char **output_str)
 {
-       size_t ret, inbytesleft = 0, outbytesleft, bufsize;
+       size_t ret, inbytesleft = 0, outbytesleft, bufsize, input_size;
        const char *str = p, *fromcode;
        char *inbuf = (char *) p, *outbuf, *buf;
        iconv_t cd;
@@ -101,6 +78,7 @@ void tracer_convert_string_to_utf8(const void *p, uint8_t unit_size, enum side_t
                }
                for (; *p16; p16++)
                        inbytesleft += 2;
+               input_size = inbytesleft + 2;
                /*
                 * Worse case is U+FFFF UTF-16 (2 bytes) converting to
                 * { ef, bf, bf } UTF-8 (3 bytes).
@@ -129,6 +107,7 @@ void tracer_convert_string_to_utf8(const void *p, uint8_t unit_size, enum side_t
                }
                for (; *p32; p32++)
                        inbytesleft += 4;
+               input_size = inbytesleft + 4;
                /*
                 * Each 4-byte UTF-32 character converts to at most a
                 * 4-byte UTF-8 character.
@@ -167,12 +146,12 @@ void tracer_convert_string_to_utf8(const void *p, uint8_t unit_size, enum side_t
                abort();
        }
        if (strlen_with_null)
-               *strlen_with_null = outbuf - buf;
+               *strlen_with_null = input_size;
        *output_str = buf;
 }
 
 static
-void tracer_print_string(const void *p, uint8_t unit_size, enum side_type_label_byte_order byte_order,
+void tracer_print_type_string(const void *p, uint8_t unit_size, enum side_type_label_byte_order byte_order,
                size_t *strlen_with_null)
 {
        char *output_str = NULL;
@@ -395,7 +374,7 @@ void tracer_print_attr_type(const char *separator, const struct side_attr *attr)
                abort();
 #endif
        case SIDE_ATTR_TYPE_STRING:
-               tracer_print_string(side_ptr_get(attr->value.u.string_value.p),
+               tracer_print_type_string(side_ptr_get(attr->value.u.string_value.p),
                                attr->value.u.string_value.unit_size,
                                side_enum_get(attr->value.u.string_value.byte_order), NULL);
                break;
@@ -414,9 +393,9 @@ void print_attributes(const char *prefix_str, const char *separator,
 
        if (!nr_attr)
                return;
-       printf("%s%s [ ", prefix_str, separator);
+       printf("%s%s [", prefix_str, separator);
        for (i = 0; i < nr_attr; i++) {
-               printf("%s", i ? ", " : "");
+               printf("%s", i ? ", " : " ");
                tracer_print_attr_type(separator, &attr[i]);
        }
        printf(" ]");
@@ -569,7 +548,7 @@ void print_enum_labels(const struct side_enum_mappings *mappings, union int_valu
                }
                if (v.s[SIDE_INTEGER128_SPLIT_LOW] >= mapping->range_begin && v.s[SIDE_INTEGER128_SPLIT_LOW] <= mapping->range_end) {
                        printf("%s", print_count++ ? ", " : "");
-                       tracer_print_string(side_ptr_get(mapping->label.p), mapping->label.unit_size,
+                       tracer_print_type_string(side_ptr_get(mapping->label.p), mapping->label.unit_size,
                                side_enum_get(mapping->label.byte_order), NULL);
                }
        }
@@ -578,25 +557,6 @@ void print_enum_labels(const struct side_enum_mappings *mappings, union int_valu
        printf(" ]");
 }
 
-static
-void tracer_print_enum(const struct side_type *type_desc, const struct side_arg *item)
-{
-       const struct side_enum_mappings *mappings = side_ptr_get(type_desc->u.side_enum.mappings);
-       const struct side_type *elem_type = side_ptr_get(type_desc->u.side_enum.elem_type);
-       union int_value v;
-
-       if (side_enum_get(elem_type->type) != side_enum_get(item->type)) {
-               fprintf(stderr, "ERROR: Unexpected enum element type\n");
-               abort();
-       }
-       v = tracer_load_integer_value(&elem_type->u.side_integer,
-                       &item->u.side_static.integer_value, 0, NULL);
-       print_attributes("attr", ":", side_ptr_get(mappings->attr), mappings->nr_attr);
-       printf("%s", mappings->nr_attr ? ", " : "");
-       tracer_print_type(elem_type, item);
-       print_enum_labels(mappings, v);
-}
-
 static
 uint32_t elem_type_to_stride(const struct side_type *elem_type)
 {
@@ -625,94 +585,6 @@ uint32_t elem_type_to_stride(const struct side_type *elem_type)
        return stride_bit;
 }
 
-static
-void tracer_print_enum_bitmap(const struct side_type *type_desc,
-               const struct side_arg *item)
-{
-       const struct side_enum_bitmap_mappings *side_enum_mappings = side_ptr_get(type_desc->u.side_enum_bitmap.mappings);
-       const struct side_type *enum_elem_type = side_ptr_get(type_desc->u.side_enum_bitmap.elem_type), *elem_type;
-       uint32_t i, print_count = 0, stride_bit, nr_items;
-       const struct side_arg *array_item;
-
-       switch (side_enum_get(enum_elem_type->type)) {
-       case SIDE_TYPE_U8:              /* Fall-through */
-       case SIDE_TYPE_BYTE:            /* Fall-through */
-       case SIDE_TYPE_U16:             /* Fall-through */
-       case SIDE_TYPE_U32:             /* Fall-through */
-       case SIDE_TYPE_U64:             /* Fall-through */
-       case SIDE_TYPE_U128:            /* Fall-through */
-       case SIDE_TYPE_S8:              /* Fall-through */
-       case SIDE_TYPE_S16:             /* Fall-through */
-       case SIDE_TYPE_S32:             /* Fall-through */
-       case SIDE_TYPE_S64:             /* Fall-through */
-       case SIDE_TYPE_S128:
-               elem_type = enum_elem_type;
-               array_item = item;
-               nr_items = 1;
-               break;
-       case SIDE_TYPE_ARRAY:
-               elem_type = side_ptr_get(enum_elem_type->u.side_array.elem_type);
-               array_item = side_ptr_get(side_ptr_get(item->u.side_static.side_array)->sav);
-               nr_items = type_desc->u.side_array.length;
-               break;
-       case SIDE_TYPE_VLA:
-               elem_type = side_ptr_get(enum_elem_type->u.side_vla.elem_type);
-               array_item = side_ptr_get(side_ptr_get(item->u.side_static.side_vla)->sav);
-               nr_items = side_ptr_get(item->u.side_static.side_vla)->len;
-               break;
-       default:
-               fprintf(stderr, "ERROR: Unexpected enum element type\n");
-               abort();
-       }
-       stride_bit = elem_type_to_stride(elem_type);
-
-       print_attributes("attr", ":", side_ptr_get(side_enum_mappings->attr), side_enum_mappings->nr_attr);
-       printf("%s", side_enum_mappings->nr_attr ? ", " : "");
-       printf("labels: [ ");
-       for (i = 0; i < side_enum_mappings->nr_mappings; i++) {
-               const struct side_enum_bitmap_mapping *mapping = &side_ptr_get(side_enum_mappings->mappings)[i];
-               bool match = false;
-               uint64_t bit;
-
-               if (mapping->range_end < mapping->range_begin) {
-                       fprintf(stderr, "ERROR: Unexpected enum bitmap range: %" PRIu64 "-%" PRIu64 "\n",
-                               mapping->range_begin, mapping->range_end);
-                       abort();
-               }
-               for (bit = mapping->range_begin; bit <= mapping->range_end; bit++) {
-                       if (bit > (nr_items * stride_bit) - 1)
-                               break;
-                       if (side_enum_get(elem_type->type) == SIDE_TYPE_BYTE) {
-                               uint8_t v = array_item[bit / 8].u.side_static.byte_value;
-                               if (v & (1ULL << (bit % 8))) {
-                                       match = true;
-                                       goto match;
-                               }
-                       } else {
-                               union int_value v = {};
-
-                               v = tracer_load_integer_value(&elem_type->u.side_integer,
-                                               &array_item[bit / stride_bit].u.side_static.integer_value,
-                                               0, NULL);
-                               side_check_value_u64(v);
-                               if (v.u[SIDE_INTEGER128_SPLIT_LOW] & (1ULL << (bit % stride_bit))) {
-                                       match = true;
-                                       goto match;
-                               }
-                       }
-               }
-match:
-               if (match) {
-                       printf("%s", print_count++ ? ", " : "");
-                       tracer_print_string(side_ptr_get(mapping->label.p), mapping->label.unit_size,
-                               side_enum_get(mapping->label.byte_order), NULL);
-               }
-       }
-       if (!print_count)
-               printf("<NO LABEL>");
-       printf(" ]");
-}
-
 static
 void print_integer_binary(uint64_t v[NR_SIDE_INTEGER128_SPLIT], int bits)
 {
@@ -1090,973 +962,746 @@ void tracer_print_type_float(const char *separator,
 }
 
 static
-void tracer_print_type(const struct side_type *type_desc, const struct side_arg *item)
+void push_nesting(struct print_ctx *ctx)
 {
-       enum side_type_label type;
+       if (++ctx->nesting >= MAX_NESTING) {
+               fprintf(stderr, "ERROR: Nesting too deep.\n");
+               abort();
+       }
+       ctx->item_nr[ctx->nesting] = 0;
+}
 
-       switch (side_enum_get(type_desc->type)) {
-       case SIDE_TYPE_ENUM:
-               switch (side_enum_get(item->type)) {
-               case SIDE_TYPE_U8:
-               case SIDE_TYPE_U16:
-               case SIDE_TYPE_U32:
-               case SIDE_TYPE_U64:
-               case SIDE_TYPE_U128:
-               case SIDE_TYPE_S8:
-               case SIDE_TYPE_S16:
-               case SIDE_TYPE_S32:
-               case SIDE_TYPE_S64:
-               case SIDE_TYPE_S128:
-                       break;
-               default:
-                       fprintf(stderr, "ERROR: type mismatch between description and arguments\n");
-                       abort();
-                       break;
-               }
-               break;
+static
+void pop_nesting(struct print_ctx *ctx)
+{
+       ctx->item_nr[ctx->nesting] = 0;
+       if (ctx->nesting-- <= 0) {
+               fprintf(stderr, "ERROR: Nesting underflow.\n");
+               abort();
+       }
+}
 
-       case SIDE_TYPE_ENUM_BITMAP:
-               switch (side_enum_get(item->type)) {
-               case SIDE_TYPE_U8:
-               case SIDE_TYPE_BYTE:
-               case SIDE_TYPE_U16:
-               case SIDE_TYPE_U32:
-               case SIDE_TYPE_U64:
-               case SIDE_TYPE_U128:
-               case SIDE_TYPE_ARRAY:
-               case SIDE_TYPE_VLA:
-                       break;
-               default:
-                       fprintf(stderr, "ERROR: type mismatch between description and arguments\n");
-                       abort();
-                       break;
-               }
-               break;
+static
+int get_nested_item_nr(struct print_ctx *ctx)
+{
+       return ctx->item_nr[ctx->nesting];
+}
 
-       case SIDE_TYPE_GATHER_ENUM:
-               switch (side_enum_get(item->type)) {
-               case SIDE_TYPE_GATHER_INTEGER:
-                       break;
-               default:
-                       fprintf(stderr, "ERROR: type mismatch between description and arguments\n");
-                       abort();
-                       break;
-               }
-               break;
+static
+void inc_nested_item_nr(struct print_ctx *ctx)
+{
+       ctx->item_nr[ctx->nesting]++;
+}
 
-       case SIDE_TYPE_DYNAMIC:
-               switch (side_enum_get(item->type)) {
-               case SIDE_TYPE_DYNAMIC_NULL:
-               case SIDE_TYPE_DYNAMIC_BOOL:
-               case SIDE_TYPE_DYNAMIC_INTEGER:
-               case SIDE_TYPE_DYNAMIC_BYTE:
-               case SIDE_TYPE_DYNAMIC_POINTER:
-               case SIDE_TYPE_DYNAMIC_FLOAT:
-               case SIDE_TYPE_DYNAMIC_STRING:
-               case SIDE_TYPE_DYNAMIC_STRUCT:
-               case SIDE_TYPE_DYNAMIC_STRUCT_VISITOR:
-               case SIDE_TYPE_DYNAMIC_VLA:
-               case SIDE_TYPE_DYNAMIC_VLA_VISITOR:
-                       break;
-               default:
-                       fprintf(stderr, "ERROR: Unexpected dynamic type\n");
-                       abort();
-                       break;
-               }
-               break;
+static
+void tracer_print_event(enum side_type_visitor_location loc,
+               const struct side_event_description *desc,
+               const struct side_arg_vec *side_arg_vec,
+               const struct side_arg_dynamic_struct *var_struct __attribute__((unused)),
+               void *caller_addr, void *priv __attribute__((unused)))
+{
+       uint32_t side_sav_len = side_arg_vec->len;
 
-       default:
-               if (side_enum_get(type_desc->type) != side_enum_get(item->type)) {
-                       fprintf(stderr, "ERROR: type mismatch between description and arguments\n");
-                       abort();
-               }
-               break;
+       if (desc->nr_fields != side_sav_len) {
+               fprintf(stderr, "ERROR: number of fields mismatch between description and arguments\n");
+               abort();
        }
 
-       if (side_enum_get(type_desc->type) == SIDE_TYPE_ENUM || side_enum_get(type_desc->type) == SIDE_TYPE_ENUM_BITMAP || side_enum_get(type_desc->type) == SIDE_TYPE_GATHER_ENUM)
-               type = side_enum_get(type_desc->type);
-       else
-               type = side_enum_get(item->type);
-
-       printf("{ ");
-       switch (type) {
-               /* Stack-copy basic types */
-       case SIDE_TYPE_NULL:
-               tracer_print_type_header(":", side_ptr_get(type_desc->u.side_null.attr),
-                       type_desc->u.side_null.nr_attr);
-               printf("<NULL TYPE>");
-               break;
-
-       case SIDE_TYPE_BOOL:
-               tracer_print_type_bool(":", &type_desc->u.side_bool, &item->u.side_static.bool_value, 0);
+       switch (loc) {
+       case SIDE_TYPE_VISITOR_BEFORE:
+               if (print_caller)
+                       printf("caller: [%p], ", caller_addr);
+               printf("provider: %s, event: %s",
+                       side_ptr_get(desc->provider_name),
+                       side_ptr_get(desc->event_name));
+               print_attributes(", attr", ":", side_ptr_get(desc->attr), desc->nr_attr);
                break;
-
-       case SIDE_TYPE_U8:
-       case SIDE_TYPE_U16:
-       case SIDE_TYPE_U32:
-       case SIDE_TYPE_U64:
-       case SIDE_TYPE_U128:
-       case SIDE_TYPE_S8:
-       case SIDE_TYPE_S16:
-       case SIDE_TYPE_S32:
-       case SIDE_TYPE_S64:
-       case SIDE_TYPE_S128:
-               tracer_print_type_integer(":", &type_desc->u.side_integer, &item->u.side_static.integer_value, 0,
-                               TRACER_DISPLAY_BASE_10);
+       case SIDE_TYPE_VISITOR_AFTER:
+               printf("\n");
                break;
+       }
+}
 
-       case SIDE_TYPE_BYTE:
-               tracer_print_type_header(":", side_ptr_get(type_desc->u.side_byte.attr), type_desc->u.side_byte.nr_attr);
-               printf("0x%" PRIx8, item->u.side_static.byte_value);
-               break;
+static
+void tracer_print_static_fields(enum side_type_visitor_location loc,
+               const struct side_arg_vec *side_arg_vec,
+               void *priv)
+{
+       struct print_ctx *ctx = (struct print_ctx *) priv;
+       uint32_t side_sav_len = side_arg_vec->len;
 
-       case SIDE_TYPE_POINTER:
-               tracer_print_type_integer(":", &type_desc->u.side_integer, &item->u.side_static.integer_value, 0,
-                               TRACER_DISPLAY_BASE_16);
+       switch (loc) {
+       case SIDE_TYPE_VISITOR_BEFORE:
+               printf("%s", side_sav_len ? ", fields: {" : "");
+               push_nesting(ctx);
                break;
-
-       case SIDE_TYPE_FLOAT_BINARY16:
-       case SIDE_TYPE_FLOAT_BINARY32:
-       case SIDE_TYPE_FLOAT_BINARY64:
-       case SIDE_TYPE_FLOAT_BINARY128:
-               tracer_print_type_float(":", &type_desc->u.side_float, &item->u.side_static.float_value);
+       case SIDE_TYPE_VISITOR_AFTER:
+               pop_nesting(ctx);
+               if (side_sav_len)
+                       printf(" }");
                break;
+       }
+}
 
-       case SIDE_TYPE_STRING_UTF8:
-       case SIDE_TYPE_STRING_UTF16:
-       case SIDE_TYPE_STRING_UTF32:
-               tracer_print_type_header(":", side_ptr_get(type_desc->u.side_string.attr), type_desc->u.side_string.nr_attr);
-               tracer_print_string(side_ptr_get(item->u.side_static.string_value),
-                               type_desc->u.side_string.unit_size, side_enum_get(type_desc->u.side_string.byte_order), NULL);
-               break;
+static
+void tracer_print_variadic_fields(enum side_type_visitor_location loc,
+               const struct side_arg_dynamic_struct *var_struct,
+               void *priv)
+{
+       struct print_ctx *ctx = (struct print_ctx *) priv;
+       uint32_t var_struct_len = var_struct->len;
 
-               /* Stack-copy compound types */
-       case SIDE_TYPE_STRUCT:
-               tracer_print_struct(type_desc, side_ptr_get(item->u.side_static.side_struct));
-               break;
-       case SIDE_TYPE_VARIANT:
-               tracer_print_variant(type_desc, side_ptr_get(item->u.side_static.side_variant));
-               break;
-       case SIDE_TYPE_ARRAY:
-               tracer_print_array(type_desc, side_ptr_get(item->u.side_static.side_array));
-               break;
-       case SIDE_TYPE_VLA:
-               tracer_print_vla(type_desc, side_ptr_get(item->u.side_static.side_vla));
+       switch (loc) {
+       case SIDE_TYPE_VISITOR_BEFORE:
+               print_attributes(", attr ", "::", side_ptr_get(var_struct->attr), var_struct->nr_attr);
+               printf("%s", var_struct_len ? ", fields:: {" : "");
+               push_nesting(ctx);
                break;
-       case SIDE_TYPE_VLA_VISITOR:
-               tracer_print_vla_visitor(type_desc, side_ptr_get(item->u.side_static.side_vla_visitor));
+       case SIDE_TYPE_VISITOR_AFTER:
+               pop_nesting(ctx);
+               if (var_struct_len)
+                       printf(" }");
                break;
+       }
+}
 
-               /* Stack-copy enumeration types */
-       case SIDE_TYPE_ENUM:
-               tracer_print_enum(type_desc, item);
-               break;
-       case SIDE_TYPE_ENUM_BITMAP:
-               tracer_print_enum_bitmap(type_desc, item);
-               break;
+static
+void tracer_print_field(enum side_type_visitor_location loc, const struct side_event_field *item_desc, void *priv)
+{
+       struct print_ctx *ctx = (struct print_ctx *) priv;
 
-               /* Gather basic types */
-       case SIDE_TYPE_GATHER_BOOL:
-               (void) tracer_print_gather_bool_type(&type_desc->u.side_gather, side_ptr_get(item->u.side_static.side_bool_gather_ptr));
-               break;
-       case SIDE_TYPE_GATHER_INTEGER:
-               (void) tracer_print_gather_integer_type(&type_desc->u.side_gather, side_ptr_get(item->u.side_static.side_integer_gather_ptr),
-                                       TRACER_DISPLAY_BASE_10);
-               break;
-       case SIDE_TYPE_GATHER_BYTE:
-               (void) tracer_print_gather_byte_type(&type_desc->u.side_gather, side_ptr_get(item->u.side_static.side_byte_gather_ptr));
-               break;
-       case SIDE_TYPE_GATHER_POINTER:
-               (void) tracer_print_gather_integer_type(&type_desc->u.side_gather, side_ptr_get(item->u.side_static.side_integer_gather_ptr),
-                                       TRACER_DISPLAY_BASE_16);
+       switch (loc) {
+       case SIDE_TYPE_VISITOR_BEFORE:
+               if (get_nested_item_nr(ctx) != 0)
+                       printf(",");
+               printf(" %s: { ", side_ptr_get(item_desc->field_name));
                break;
-       case SIDE_TYPE_GATHER_FLOAT:
-               (void) tracer_print_gather_float_type(&type_desc->u.side_gather, side_ptr_get(item->u.side_static.side_float_gather_ptr));
-               break;
-       case SIDE_TYPE_GATHER_STRING:
-               (void) tracer_print_gather_string_type(&type_desc->u.side_gather, side_ptr_get(item->u.side_static.side_string_gather_ptr));
+       case SIDE_TYPE_VISITOR_AFTER:
+               printf(" }");
+               inc_nested_item_nr(ctx);
                break;
+       }
+}
 
-               /* Gather compound type */
-       case SIDE_TYPE_GATHER_STRUCT:
-               (void) tracer_print_gather_struct(&type_desc->u.side_gather, side_ptr_get(item->u.side_static.side_struct_gather_ptr));
-               break;
-       case SIDE_TYPE_GATHER_ARRAY:
-               (void) tracer_print_gather_array(&type_desc->u.side_gather, side_ptr_get(item->u.side_static.side_array_gather_ptr));
-               break;
-       case SIDE_TYPE_GATHER_VLA:
-               (void) tracer_print_gather_vla(&type_desc->u.side_gather, side_ptr_get(item->u.side_static.side_vla_gather.ptr),
-                               side_ptr_get(item->u.side_static.side_vla_gather.length_ptr));
-               break;
+static
+void tracer_print_elem(enum side_type_visitor_location loc, const struct side_type *type_desc __attribute__((unused)), void *priv)
+{
+       struct print_ctx *ctx = (struct print_ctx *) priv;
 
-               /* Gather enumeration types */
-       case SIDE_TYPE_GATHER_ENUM:
-               (void) tracer_print_gather_enum_type(&type_desc->u.side_gather, side_ptr_get(item->u.side_static.side_integer_gather_ptr));
+       switch (loc) {
+       case SIDE_TYPE_VISITOR_BEFORE:
+               if (get_nested_item_nr(ctx) != 0)
+                       printf(", { ");
+               else
+                       printf(" { ");
                break;
-
-       /* Dynamic basic types */
-       case SIDE_TYPE_DYNAMIC_NULL:
-       case SIDE_TYPE_DYNAMIC_BOOL:
-       case SIDE_TYPE_DYNAMIC_INTEGER:
-       case SIDE_TYPE_DYNAMIC_BYTE:
-       case SIDE_TYPE_DYNAMIC_POINTER:
-       case SIDE_TYPE_DYNAMIC_FLOAT:
-       case SIDE_TYPE_DYNAMIC_STRING:
-
-       /* Dynamic compound types */
-       case SIDE_TYPE_DYNAMIC_STRUCT:
-       case SIDE_TYPE_DYNAMIC_STRUCT_VISITOR:
-       case SIDE_TYPE_DYNAMIC_VLA:
-       case SIDE_TYPE_DYNAMIC_VLA_VISITOR:
-               tracer_print_dynamic(item);
+       case SIDE_TYPE_VISITOR_AFTER:
+               printf(" }");
+               inc_nested_item_nr(ctx);
                break;
-       default:
-               fprintf(stderr, "<UNKNOWN TYPE>\n");
-               abort();
        }
-       printf(" }");
 }
 
 static
-void tracer_print_field(const struct side_event_field *item_desc, const struct side_arg *item)
+void tracer_print_null(const struct side_type *type_desc,
+               const struct side_arg *item __attribute__((unused)),
+               void *priv __attribute__((unused)))
 {
-       printf("%s: ", side_ptr_get(item_desc->field_name));
-       tracer_print_type(&item_desc->side_type, item);
+       tracer_print_type_header(":", side_ptr_get(type_desc->u.side_null.attr),
+               type_desc->u.side_null.nr_attr);
+       printf("<NULL TYPE>");
 }
 
 static
-void tracer_print_struct(const struct side_type *type_desc, const struct side_arg_vec *side_arg_vec)
+void tracer_print_bool(const struct side_type *type_desc,
+               const struct side_arg *item,
+               void *priv __attribute__((unused)))
 {
-       const struct side_arg *sav = side_ptr_get(side_arg_vec->sav);
-       const struct side_type_struct *side_struct = side_ptr_get(type_desc->u.side_struct);
-       uint32_t i, side_sav_len = side_arg_vec->len;
+       tracer_print_type_bool(":", &type_desc->u.side_bool, &item->u.side_static.bool_value, 0);
+}
 
-       if (side_struct->nr_fields != side_sav_len) {
-               fprintf(stderr, "ERROR: number of fields mismatch between description and arguments of structure\n");
-               abort();
-       }
-       print_attributes("attr", ":", side_ptr_get(side_struct->attr), side_struct->nr_attr);
-       printf("%s", side_struct->nr_attr ? ", " : "");
-       printf("fields: { ");
-       for (i = 0; i < side_sav_len; i++) {
-               printf("%s", i ? ", " : "");
-               tracer_print_field(&side_ptr_get(side_struct->fields)[i], &sav[i]);
-       }
-       printf(" }");
+static
+void tracer_print_integer(const struct side_type *type_desc,
+               const struct side_arg *item,
+               void *priv __attribute__((unused)))
+{
+       tracer_print_type_integer(":", &type_desc->u.side_integer, &item->u.side_static.integer_value, 0, TRACER_DISPLAY_BASE_10);
 }
 
 static
-void tracer_print_variant(const struct side_type *type_desc, const struct side_arg_variant *side_arg_variant)
+void tracer_print_byte(const struct side_type *type_desc __attribute__((unused)),
+               const struct side_arg *item,
+               void *priv __attribute__((unused)))
 {
-       const struct side_type_variant *side_type_variant = side_ptr_get(type_desc->u.side_variant);
-       const struct side_type *selector_type = &side_type_variant->selector;
-       union int_value v;
-       uint32_t i;
-
-       if (side_enum_get(selector_type->type) != side_enum_get(side_arg_variant->selector.type)) {
-               fprintf(stderr, "ERROR: Unexpected variant selector type\n");
-               abort();
-       }
-       switch (side_enum_get(selector_type->type)) {
-       case SIDE_TYPE_U8:
-       case SIDE_TYPE_U16:
-       case SIDE_TYPE_U32:
-       case SIDE_TYPE_U64:
-       case SIDE_TYPE_U128:
-       case SIDE_TYPE_S8:
-       case SIDE_TYPE_S16:
-       case SIDE_TYPE_S32:
-       case SIDE_TYPE_S64:
-       case SIDE_TYPE_S128:
-               break;
-       default:
-               fprintf(stderr, "ERROR: Expecting integer variant selector type\n");
-               abort();
-       }
-       v = tracer_load_integer_value(&selector_type->u.side_integer,
-                       &side_arg_variant->selector.u.side_static.integer_value, 0, NULL);
-       side_check_value_u64(v);
-       for (i = 0; i < side_type_variant->nr_options; i++) {
-               const struct side_variant_option *option = &side_ptr_get(side_type_variant->options)[i];
-
-               if (v.s[SIDE_INTEGER128_SPLIT_LOW] >= option->range_begin && v.s[SIDE_INTEGER128_SPLIT_LOW] <= option->range_end) {
-                       tracer_print_type(&option->side_type, &side_arg_variant->option);
-                       return;
-               }
-       }
-       fprintf(stderr, "ERROR: Variant selector value unknown %" PRId64 "\n", v.s[SIDE_INTEGER128_SPLIT_LOW]);
-       abort();
-}
+       tracer_print_type_header(":", side_ptr_get(type_desc->u.side_byte.attr), type_desc->u.side_byte.nr_attr);
+       printf("0x%" PRIx8, item->u.side_static.byte_value);
+}
 
 static
-void tracer_print_array(const struct side_type *type_desc, const struct side_arg_vec *side_arg_vec)
+void tracer_print_pointer(const struct side_type *type_desc,
+               const struct side_arg *item,
+               void *priv __attribute__((unused)))
 {
-       const struct side_arg *sav = side_ptr_get(side_arg_vec->sav);
-       uint32_t i, side_sav_len = side_arg_vec->len;
-
-       if (type_desc->u.side_array.length != side_sav_len) {
-               fprintf(stderr, "ERROR: length mismatch between description and arguments of array\n");
-               abort();
-       }
-       print_attributes("attr", ":", side_ptr_get(type_desc->u.side_array.attr), type_desc->u.side_array.nr_attr);
-       printf("%s", type_desc->u.side_array.nr_attr ? ", " : "");
-       printf("elements: ");
-       printf("[ ");
-       for (i = 0; i < side_sav_len; i++) {
-               printf("%s", i ? ", " : "");
-               tracer_print_type(side_ptr_get(type_desc->u.side_array.elem_type), &sav[i]);
-       }
-       printf(" ]");
+       tracer_print_type_integer(":", &type_desc->u.side_integer, &item->u.side_static.integer_value, 0, TRACER_DISPLAY_BASE_16);
 }
 
 static
-void tracer_print_vla(const struct side_type *type_desc, const struct side_arg_vec *side_arg_vec)
+void tracer_print_float(const struct side_type *type_desc,
+               const struct side_arg *item,
+               void *priv __attribute__((unused)))
 {
-       const struct side_arg *sav = side_ptr_get(side_arg_vec->sav);
-       uint32_t i, side_sav_len = side_arg_vec->len;
-
-       print_attributes("attr", ":", side_ptr_get(type_desc->u.side_vla.attr), type_desc->u.side_vla.nr_attr);
-       printf("%s", type_desc->u.side_vla.nr_attr ? ", " : "");
-       printf("elements: ");
-       printf("[ ");
-       for (i = 0; i < side_sav_len; i++) {
-               printf("%s", i ? ", " : "");
-               tracer_print_type(side_ptr_get(type_desc->u.side_vla.elem_type), &sav[i]);
-       }
-       printf(" ]");
+       tracer_print_type_float(":", &type_desc->u.side_float, &item->u.side_static.float_value);
 }
 
 static
-const char *tracer_gather_access(enum side_type_gather_access_mode access_mode, const char *ptr)
+void tracer_print_string(const struct side_type *type_desc,
+               const struct side_arg *item,
+               void *priv __attribute__((unused)))
 {
-       switch (access_mode) {
-       case SIDE_TYPE_GATHER_ACCESS_DIRECT:
-               return ptr;
-       case SIDE_TYPE_GATHER_ACCESS_POINTER:
-               /* Dereference pointer */
-               memcpy(&ptr, ptr, sizeof(const char *));
-               return ptr;
-       default:
-               abort();
-       }
+       tracer_print_type_header(":", side_ptr_get(type_desc->u.side_string.attr), type_desc->u.side_string.nr_attr);
+       tracer_print_type_string(side_ptr_get(item->u.side_static.string_value),
+                       type_desc->u.side_string.unit_size,
+                       side_enum_get(type_desc->u.side_string.byte_order), NULL);
 }
 
 static
-uint32_t tracer_gather_size(enum side_type_gather_access_mode access_mode, uint32_t len)
+void tracer_print_struct(enum side_type_visitor_location loc,
+       const struct side_type_struct *side_struct,
+       const struct side_arg_vec *side_arg_vec __attribute__((unused)), void *priv)
 {
-       switch (access_mode) {
-       case SIDE_TYPE_GATHER_ACCESS_DIRECT:
-               return len;
-       case SIDE_TYPE_GATHER_ACCESS_POINTER:
-               return sizeof(void *);
-       default:
-               abort();
+       struct print_ctx *ctx = (struct print_ctx *) priv;
+
+       switch (loc) {
+       case SIDE_TYPE_VISITOR_BEFORE:
+               print_attributes("attr", ":", side_ptr_get(side_struct->attr), side_struct->nr_attr);
+               printf("%s", side_struct->nr_attr ? ", " : "");
+               printf("fields: {");
+               push_nesting(ctx);
+               break;
+       case SIDE_TYPE_VISITOR_AFTER:
+               pop_nesting(ctx);
+               printf(" }");
+               break;
        }
 }
 
 static
-union int_value tracer_load_gather_integer_value(const struct side_type_gather_integer *side_integer,
-               const void *_ptr)
+void tracer_print_array(enum side_type_visitor_location loc,
+       const struct side_type_array *side_array,
+       const struct side_arg_vec *side_arg_vec __attribute__((unused)), void *priv)
 {
-       enum side_type_gather_access_mode access_mode =
-               (enum side_type_gather_access_mode) side_integer->access_mode;
-       uint32_t integer_size_bytes = side_integer->type.integer_size;
-       const char *ptr = (const char *) _ptr;
-       union side_integer_value value;
+       struct print_ctx *ctx = (struct print_ctx *) priv;
 
-       ptr = tracer_gather_access(access_mode, ptr + side_integer->offset);
-       memcpy(&value, ptr, integer_size_bytes);
-       return tracer_load_integer_value(&side_integer->type, &value,
-                       side_integer->offset_bits, NULL);
+       switch (loc) {
+       case SIDE_TYPE_VISITOR_BEFORE:
+               print_attributes("attr", ":", side_ptr_get(side_array->attr), side_array->nr_attr);
+               printf("%s", side_array->nr_attr ? ", " : "");
+               printf("elements: [");
+               push_nesting(ctx);
+               break;
+       case SIDE_TYPE_VISITOR_AFTER:
+               pop_nesting(ctx);
+               printf(" ]");
+               break;
+       }
 }
 
 static
-uint32_t tracer_print_gather_bool_type(const struct side_type_gather *type_gather, const void *_ptr)
+void tracer_print_vla(enum side_type_visitor_location loc,
+       const struct side_type_vla *side_vla,
+       const struct side_arg_vec *side_arg_vec __attribute__((unused)), void *priv)
 {
-       enum side_type_gather_access_mode access_mode =
-               (enum side_type_gather_access_mode) type_gather->u.side_bool.access_mode;
-       uint32_t bool_size_bytes = type_gather->u.side_bool.type.bool_size;
-       const char *ptr = (const char *) _ptr;
-       union side_bool_value value;
+       struct print_ctx *ctx = (struct print_ctx *) priv;
 
-       switch (bool_size_bytes) {
-       case 1:
-       case 2:
-       case 4:
-       case 8:
+       switch (loc) {
+       case SIDE_TYPE_VISITOR_BEFORE:
+               print_attributes("attr", ":", side_ptr_get(side_vla->attr), side_vla->nr_attr);
+               printf("%s", side_vla->nr_attr ? ", " : "");
+               printf("elements: [");
+               push_nesting(ctx);
+               break;
+       case SIDE_TYPE_VISITOR_AFTER:
+               pop_nesting(ctx);
+               printf(" ]");
                break;
-       default:
-               abort();
        }
-       ptr = tracer_gather_access(access_mode, ptr + type_gather->u.side_bool.offset);
-       memcpy(&value, ptr, bool_size_bytes);
-       tracer_print_type_bool(":", &type_gather->u.side_bool.type, &value,
-                       type_gather->u.side_bool.offset_bits);
-       return tracer_gather_size(access_mode, bool_size_bytes);
 }
 
 static
-uint32_t tracer_print_gather_byte_type(const struct side_type_gather *type_gather, const void *_ptr)
+void tracer_print_vla_visitor(enum side_type_visitor_location loc,
+       const struct side_type_vla_visitor *side_vla_visitor,
+       const struct side_arg_vla_visitor *side_arg_vla_visitor __attribute__((unused)), void *priv)
 {
-       enum side_type_gather_access_mode access_mode =
-               (enum side_type_gather_access_mode) type_gather->u.side_byte.access_mode;
-       const char *ptr = (const char *) _ptr;
-       uint8_t value;
+       struct print_ctx *ctx = (struct print_ctx *) priv;
 
-       ptr = tracer_gather_access(access_mode, ptr + type_gather->u.side_byte.offset);
-       memcpy(&value, ptr, 1);
-       tracer_print_type_header(":", side_ptr_get(type_gather->u.side_byte.type.attr),
-                       type_gather->u.side_byte.type.nr_attr);
-       printf("0x%" PRIx8, value);
-       return tracer_gather_size(access_mode, 1);
+       switch (loc) {
+       case SIDE_TYPE_VISITOR_BEFORE:
+               print_attributes("attr", ":", side_ptr_get(side_vla_visitor->attr), side_vla_visitor->nr_attr);
+               printf("%s", side_vla_visitor->nr_attr ? ", " : "");
+               printf("elements: [");
+               push_nesting(ctx);
+               break;
+       case SIDE_TYPE_VISITOR_AFTER:
+               pop_nesting(ctx);
+               printf(" ]");
+               break;
+       }
 }
 
-static
-uint32_t tracer_print_gather_integer_type(const struct side_type_gather *type_gather, const void *_ptr,
-               enum tracer_display_base default_base)
+static void tracer_print_enum(const struct side_type *type_desc,
+       const struct side_arg *item, void *priv)
 {
-       enum side_type_gather_access_mode access_mode =
-               (enum side_type_gather_access_mode) type_gather->u.side_integer.access_mode;
-       uint32_t integer_size_bytes = type_gather->u.side_integer.type.integer_size;
-       const char *ptr = (const char *) _ptr;
-       union side_integer_value value;
+       const struct side_enum_mappings *mappings = side_ptr_get(type_desc->u.side_enum.mappings);
+       const struct side_type *elem_type = side_ptr_get(type_desc->u.side_enum.elem_type);
+       union int_value v;
 
-       switch (integer_size_bytes) {
-       case 1:
-       case 2:
-       case 4:
-       case 8:
-       case 16:
-               break;
-       default:
+       if (side_enum_get(elem_type->type) != side_enum_get(item->type)) {
+               fprintf(stderr, "ERROR: Unexpected enum element type\n");
                abort();
        }
-       ptr = tracer_gather_access(access_mode, ptr + type_gather->u.side_integer.offset);
-       memcpy(&value, ptr, integer_size_bytes);
-       tracer_print_type_integer(":", &type_gather->u.side_integer.type, &value,
-                       type_gather->u.side_integer.offset_bits, default_base);
-       return tracer_gather_size(access_mode, integer_size_bytes);
+       v = tracer_load_integer_value(&elem_type->u.side_integer,
+                       &item->u.side_static.integer_value, 0, NULL);
+       print_attributes("attr", ":", side_ptr_get(mappings->attr), mappings->nr_attr);
+       printf("%s", mappings->nr_attr ? ", " : "");
+       printf("{ ");
+       tracer_print_integer(elem_type, item, priv);
+       printf(" }");
+       print_enum_labels(mappings, v);
 }
 
-static
-uint32_t tracer_print_gather_float_type(const struct side_type_gather *type_gather, const void *_ptr)
+static void tracer_print_enum_bitmap(const struct side_type *type_desc,
+       const struct side_arg *item, void *priv __attribute__((unused)))
 {
-       enum side_type_gather_access_mode access_mode =
-               (enum side_type_gather_access_mode) type_gather->u.side_float.access_mode;
-       uint32_t float_size_bytes = type_gather->u.side_float.type.float_size;
-       const char *ptr = (const char *) _ptr;
-       union side_float_value value;
+       const struct side_enum_bitmap_mappings *side_enum_mappings = side_ptr_get(type_desc->u.side_enum_bitmap.mappings);
+       const struct side_type *enum_elem_type = side_ptr_get(type_desc->u.side_enum_bitmap.elem_type), *elem_type;
+       uint32_t i, print_count = 0, stride_bit, nr_items;
+       const struct side_arg *array_item;
 
-       switch (float_size_bytes) {
-       case 2:
-       case 4:
-       case 8:
-       case 16:
+       switch (side_enum_get(enum_elem_type->type)) {
+       case SIDE_TYPE_U8:              /* Fall-through */
+       case SIDE_TYPE_BYTE:            /* Fall-through */
+       case SIDE_TYPE_U16:             /* Fall-through */
+       case SIDE_TYPE_U32:             /* Fall-through */
+       case SIDE_TYPE_U64:             /* Fall-through */
+       case SIDE_TYPE_U128:            /* Fall-through */
+       case SIDE_TYPE_S8:              /* Fall-through */
+       case SIDE_TYPE_S16:             /* Fall-through */
+       case SIDE_TYPE_S32:             /* Fall-through */
+       case SIDE_TYPE_S64:             /* Fall-through */
+       case SIDE_TYPE_S128:
+               elem_type = enum_elem_type;
+               array_item = item;
+               nr_items = 1;
+               break;
+       case SIDE_TYPE_ARRAY:
+               elem_type = side_ptr_get(enum_elem_type->u.side_array.elem_type);
+               array_item = side_ptr_get(side_ptr_get(item->u.side_static.side_array)->sav);
+               nr_items = type_desc->u.side_array.length;
+               break;
+       case SIDE_TYPE_VLA:
+               elem_type = side_ptr_get(enum_elem_type->u.side_vla.elem_type);
+               array_item = side_ptr_get(side_ptr_get(item->u.side_static.side_vla)->sav);
+               nr_items = side_ptr_get(item->u.side_static.side_vla)->len;
                break;
        default:
+               fprintf(stderr, "ERROR: Unexpected enum element type\n");
                abort();
        }
-       ptr = tracer_gather_access(access_mode, ptr + type_gather->u.side_float.offset);
-       memcpy(&value, ptr, float_size_bytes);
-       tracer_print_type_float(":", &type_gather->u.side_float.type, &value);
-       return tracer_gather_size(access_mode, float_size_bytes);
-}
+       stride_bit = elem_type_to_stride(elem_type);
 
-static
-uint32_t tracer_print_gather_string_type(const struct side_type_gather *type_gather, const void *_ptr)
-{
-       enum side_type_gather_access_mode access_mode =
-               (enum side_type_gather_access_mode) type_gather->u.side_string.access_mode;
-       const char *ptr = (const char *) _ptr;
-       size_t string_len;
+       print_attributes("attr", ":", side_ptr_get(side_enum_mappings->attr), side_enum_mappings->nr_attr);
+       printf("%s", side_enum_mappings->nr_attr ? ", " : "");
+       printf("labels: [ ");
+       for (i = 0; i < side_enum_mappings->nr_mappings; i++) {
+               const struct side_enum_bitmap_mapping *mapping = &side_ptr_get(side_enum_mappings->mappings)[i];
+               bool match = false;
+               uint64_t bit;
 
-       ptr = tracer_gather_access(access_mode, ptr + type_gather->u.side_string.offset);
-       tracer_print_type_header(":", side_ptr_get(type_gather->u.side_string.type.attr),
-                       type_gather->u.side_string.type.nr_attr);
-       if (ptr) {
-               tracer_print_string(ptr, type_gather->u.side_string.type.unit_size,
-                               side_enum_get(type_gather->u.side_string.type.byte_order), &string_len);
-       } else {
-               printf("<NULL>");
-               string_len = type_gather->u.side_string.type.unit_size;
+               if (mapping->range_end < mapping->range_begin) {
+                       fprintf(stderr, "ERROR: Unexpected enum bitmap range: %" PRIu64 "-%" PRIu64 "\n",
+                               mapping->range_begin, mapping->range_end);
+                       abort();
+               }
+               for (bit = mapping->range_begin; bit <= mapping->range_end; bit++) {
+                       if (bit > (nr_items * stride_bit) - 1)
+                               break;
+                       if (side_enum_get(elem_type->type) == SIDE_TYPE_BYTE) {
+                               uint8_t v = array_item[bit / 8].u.side_static.byte_value;
+                               if (v & (1ULL << (bit % 8))) {
+                                       match = true;
+                                       goto match;
+                               }
+                       } else {
+                               union int_value v = {};
+
+                               v = tracer_load_integer_value(&elem_type->u.side_integer,
+                                               &array_item[bit / stride_bit].u.side_static.integer_value,
+                                               0, NULL);
+                               side_check_value_u64(v);
+                               if (v.u[SIDE_INTEGER128_SPLIT_LOW] & (1ULL << (bit % stride_bit))) {
+                                       match = true;
+                                       goto match;
+                               }
+                       }
+               }
+match:
+               if (match) {
+                       printf("%s", print_count++ ? ", " : "");
+                       tracer_print_type_string(side_ptr_get(mapping->label.p), mapping->label.unit_size,
+                               side_enum_get(mapping->label.byte_order), NULL);
+               }
        }
-       return tracer_gather_size(access_mode, string_len);
+       if (!print_count)
+               printf("<NO LABEL>");
+       printf(" ]");
 }
 
 static
-uint32_t tracer_print_gather_type(const struct side_type *type_desc, const void *ptr)
+void tracer_print_gather_bool(const struct side_type_gather_bool *type,
+       const union side_bool_value *value,
+       void *priv __attribute__((unused)))
 {
-       uint32_t len;
+       tracer_print_type_bool(":", &type->type, value, type->offset_bits);
+}
 
-       printf("{ ");
-       switch (side_enum_get(type_desc->type)) {
-               /* Gather basic types */
-       case SIDE_TYPE_GATHER_BOOL:
-               len = tracer_print_gather_bool_type(&type_desc->u.side_gather, ptr);
-               break;
-       case SIDE_TYPE_GATHER_INTEGER:
-               len = tracer_print_gather_integer_type(&type_desc->u.side_gather, ptr,
-                               TRACER_DISPLAY_BASE_10);
-               break;
-       case SIDE_TYPE_GATHER_BYTE:
-               len = tracer_print_gather_byte_type(&type_desc->u.side_gather, ptr);
-               break;
-       case SIDE_TYPE_GATHER_POINTER:
-               len = tracer_print_gather_integer_type(&type_desc->u.side_gather, ptr,
-                               TRACER_DISPLAY_BASE_16);
-               break;
-       case SIDE_TYPE_GATHER_FLOAT:
-               len = tracer_print_gather_float_type(&type_desc->u.side_gather, ptr);
-               break;
-       case SIDE_TYPE_GATHER_STRING:
-               len = tracer_print_gather_string_type(&type_desc->u.side_gather, ptr);
-               break;
+static
+void tracer_print_gather_byte(const struct side_type_gather_byte *type,
+       const uint8_t *_ptr,
+       void *priv __attribute__((unused)))
+{
+       tracer_print_type_header(":", side_ptr_get(type->type.attr),
+                       type->type.nr_attr);
+       printf("0x%" PRIx8, *_ptr);
+}
 
-               /* Gather enum types */
-       case SIDE_TYPE_GATHER_ENUM:
-               len = tracer_print_gather_enum_type(&type_desc->u.side_gather, ptr);
-               break;
+static
+void tracer_print_gather_integer(const struct side_type_gather_integer *type,
+       const union side_integer_value *value,
+       void *priv __attribute__((unused)))
+{
+       tracer_print_type_integer(":", &type->type, value, type->offset_bits, TRACER_DISPLAY_BASE_10);
+}
 
-               /* Gather compound types */
-       case SIDE_TYPE_GATHER_STRUCT:
-               len = tracer_print_gather_struct(&type_desc->u.side_gather, ptr);
-               break;
-       case SIDE_TYPE_GATHER_ARRAY:
-               len = tracer_print_gather_array(&type_desc->u.side_gather, ptr);
-               break;
-       case SIDE_TYPE_GATHER_VLA:
-               len = tracer_print_gather_vla(&type_desc->u.side_gather, ptr, ptr);
-               break;
-       default:
-               fprintf(stderr, "<UNKNOWN GATHER TYPE>");
-               abort();
-       }
-       printf(" }");
-       return len;
+static
+void tracer_print_gather_pointer(const struct side_type_gather_integer *type,
+       const union side_integer_value *value,
+       void *priv __attribute__((unused)))
+{
+       tracer_print_type_integer(":", &type->type, value, type->offset_bits, TRACER_DISPLAY_BASE_16);
 }
 
 static
-uint32_t tracer_print_gather_enum_type(const struct side_type_gather *type_gather, const void *_ptr)
+void tracer_print_gather_float(const struct side_type_gather_float *type,
+       const union side_float_value *value,
+       void *priv __attribute__((unused)))
 {
-       const struct side_enum_mappings *mappings = side_ptr_get(type_gather->u.side_enum.mappings);
-       const struct side_type *enum_elem_type = side_ptr_get(type_gather->u.side_enum.elem_type);
-       const struct side_type_gather_integer *side_integer = &enum_elem_type->u.side_gather.u.side_integer;
-       enum side_type_gather_access_mode access_mode =
-               (enum side_type_gather_access_mode) side_integer->access_mode;
-       uint32_t integer_size_bytes = side_integer->type.integer_size;
-       const char *ptr = (const char *) _ptr;
-       union side_integer_value value;
-       union int_value v;
+       tracer_print_type_float(":", &type->type, value);
+}
 
-       switch (integer_size_bytes) {
-       case 1:
-       case 2:
-       case 4:
-       case 8:
-       case 16:
-               break;
-       default:
-               abort();
-       }
-       ptr = tracer_gather_access(access_mode, ptr + side_integer->offset);
-       memcpy(&value, ptr, integer_size_bytes);
-       v = tracer_load_gather_integer_value(side_integer, &value);
-       print_attributes("attr", ":", side_ptr_get(mappings->attr), mappings->nr_attr);
-       printf("%s", mappings->nr_attr ? ", " : "");
-       tracer_print_gather_type(enum_elem_type, ptr);
-       print_enum_labels(mappings, v);
-       return tracer_gather_size(access_mode, integer_size_bytes);
+static
+void tracer_print_gather_string(const struct side_type_gather_string *type,
+       const void *p, uint8_t unit_size,
+       enum side_type_label_byte_order byte_order,
+       size_t strlen_with_null __attribute__((unused)),
+       void *priv __attribute__((unused)))
+{
+       //TODO use strlen_with_null input
+       tracer_print_type_header(":", side_ptr_get(type->type.attr),
+                       type->type.nr_attr);
+       tracer_print_type_string(p, unit_size, byte_order, NULL);
 }
 
 static
-void tracer_print_gather_field(const struct side_event_field *field, const void *ptr)
+void tracer_print_gather_struct(enum side_type_visitor_location loc,
+       const struct side_type_struct *side_struct,
+       void *priv)
 {
-       printf("%s: ", side_ptr_get(field->field_name));
-       (void) tracer_print_gather_type(&field->side_type, ptr);
+       tracer_print_struct(loc, side_struct, NULL, priv);
 }
 
 static
-uint32_t tracer_print_gather_struct(const struct side_type_gather *type_gather, const void *_ptr)
+void tracer_print_gather_array(enum side_type_visitor_location loc,
+       const struct side_type_array *side_array,
+       void *priv)
 {
-       enum side_type_gather_access_mode access_mode =
-               (enum side_type_gather_access_mode) type_gather->u.side_struct.access_mode;
-       const struct side_type_struct *side_struct = side_ptr_get(type_gather->u.side_struct.type);
-       const char *ptr = (const char *) _ptr;
-       uint32_t i;
+       tracer_print_array(loc, side_array, NULL, priv);
+}
 
-       ptr = tracer_gather_access(access_mode, ptr + type_gather->u.side_struct.offset);
-       print_attributes("attr", ":", side_ptr_get(side_struct->attr), side_struct->nr_attr);
-       printf("%s", side_struct->nr_attr ? ", " : "");
-       printf("fields: { ");
-       for (i = 0; i < side_struct->nr_fields; i++) {
-               printf("%s", i ? ", " : "");
-               tracer_print_gather_field(&side_ptr_get(side_struct->fields)[i], ptr);
-       }
-       printf(" }");
-       return tracer_gather_size(access_mode, type_gather->u.side_struct.size);
+static
+void tracer_print_gather_vla(enum side_type_visitor_location loc,
+       const struct side_type_vla *side_vla,
+       uint32_t length __attribute__((unused)),
+       void *priv)
+{
+       tracer_print_vla(loc, side_vla, NULL, priv);
 }
 
 static
-uint32_t tracer_print_gather_array(const struct side_type_gather *type_gather, const void *_ptr)
+void tracer_print_gather_enum(const struct side_type_gather_enum *type,
+       const union side_integer_value *value,
+       void *priv __attribute__((unused)))
 {
-       enum side_type_gather_access_mode access_mode =
-               (enum side_type_gather_access_mode) type_gather->u.side_array.access_mode;
-       const char *ptr = (const char *) _ptr, *orig_ptr;
-       uint32_t i;
+       const struct side_enum_mappings *mappings = side_ptr_get(type->mappings);
+       const struct side_type *enum_elem_type = side_ptr_get(type->elem_type);
+       const struct side_type_gather_integer *side_integer = &enum_elem_type->u.side_gather.u.side_integer;
+       union int_value v;
 
-       ptr = tracer_gather_access(access_mode, ptr + type_gather->u.side_array.offset);
-       orig_ptr = ptr;
-       print_attributes("attr", ":", side_ptr_get(type_gather->u.side_array.type.attr), type_gather->u.side_array.type.nr_attr);
-       printf("%s", type_gather->u.side_array.type.nr_attr ? ", " : "");
-       printf("elements: ");
-       printf("[ ");
-       for (i = 0; i < type_gather->u.side_array.type.length; i++) {
-               const struct side_type *elem_type = side_ptr_get(type_gather->u.side_array.type.elem_type);
-
-               switch (side_enum_get(elem_type->type)) {
-               case SIDE_TYPE_GATHER_VLA:
-                       fprintf(stderr, "<gather VLA only supported within gather structures>\n");
-                       abort();
-               default:
-                       break;
-               }
-               printf("%s", i ? ", " : "");
-               ptr += tracer_print_gather_type(elem_type, ptr);
-       }
-       printf(" ]");
-       return tracer_gather_size(access_mode, ptr - orig_ptr);
+       v = tracer_load_integer_value(&side_integer->type, value, 0, NULL);
+       print_attributes("attr", ":", side_ptr_get(mappings->attr), mappings->nr_attr);
+       printf("%s", mappings->nr_attr ? ", " : "");
+       printf("{ ");
+       tracer_print_type_integer(":", &side_integer->type, value, 0, TRACER_DISPLAY_BASE_10);
+       printf(" }");
+       print_enum_labels(mappings, v);
 }
 
 static
-uint32_t tracer_print_gather_vla(const struct side_type_gather *type_gather, const void *_ptr,
-               const void *_length_ptr)
+void tracer_print_dynamic_field(enum side_type_visitor_location loc, const struct side_arg_dynamic_field *field, void *priv)
 {
-       enum side_type_gather_access_mode access_mode =
-               (enum side_type_gather_access_mode) type_gather->u.side_vla.access_mode;
-       const struct side_type *length_type = side_ptr_get(type_gather->u.side_vla.length_type);
-       const char *ptr = (const char *) _ptr, *orig_ptr;
-       const char *length_ptr = (const char *) _length_ptr;
-       union int_value v = {};
-       uint32_t i, length;
+       struct print_ctx *ctx = (struct print_ctx *) priv;
 
-       /* Access length */
-       switch (side_enum_get(length_type->type)) {
-       case SIDE_TYPE_GATHER_INTEGER:
+       switch (loc) {
+       case SIDE_TYPE_VISITOR_BEFORE:
+               if (get_nested_item_nr(ctx) != 0)
+                       printf(",");
+               printf(" %s:: { ", side_ptr_get(field->field_name));
+               break;
+       case SIDE_TYPE_VISITOR_AFTER:
+               printf(" }");
+               inc_nested_item_nr(ctx);
                break;
-       default:
-               fprintf(stderr, "<gather VLA expects integer gather length type>\n");
-               abort();
-       }
-       v = tracer_load_gather_integer_value(&length_type->u.side_gather.u.side_integer,
-                                       length_ptr);
-       if (v.u[SIDE_INTEGER128_SPLIT_HIGH] || v.u[SIDE_INTEGER128_SPLIT_LOW] > UINT32_MAX) {
-               fprintf(stderr, "Unexpected vla length value\n");
-               abort();
-       }
-       length = (uint32_t) v.u[SIDE_INTEGER128_SPLIT_LOW];
-       ptr = tracer_gather_access(access_mode, ptr + type_gather->u.side_vla.offset);
-       orig_ptr = ptr;
-       print_attributes("attr", ":", side_ptr_get(type_gather->u.side_vla.type.attr), type_gather->u.side_vla.type.nr_attr);
-       printf("%s", type_gather->u.side_vla.type.nr_attr ? ", " : "");
-       printf("elements: ");
-       printf("[ ");
-       for (i = 0; i < length; i++) {
-               const struct side_type *elem_type = side_ptr_get(type_gather->u.side_vla.type.elem_type);
-
-               switch (side_enum_get(elem_type->type)) {
-               case SIDE_TYPE_GATHER_VLA:
-                       fprintf(stderr, "<gather VLA only supported within gather structures>\n");
-                       abort();
-               default:
-                       break;
-               }
-               printf("%s", i ? ", " : "");
-               ptr += tracer_print_gather_type(elem_type, ptr);
        }
-       printf(" ]");
-       return tracer_gather_size(access_mode, ptr - orig_ptr);
 }
 
-struct tracer_visitor_priv {
-       const struct side_type *elem_type;
-       int i;
-};
-
 static
-enum side_visitor_status tracer_write_elem_cb(const struct side_tracer_visitor_ctx *tracer_ctx,
-                       const struct side_arg *elem)
+void tracer_print_dynamic_elem(enum side_type_visitor_location loc,
+       const struct side_arg *dynamic_item __attribute__((unused)), void *priv)
 {
-       struct tracer_visitor_priv *tracer_priv = (struct tracer_visitor_priv *) tracer_ctx->priv;
-
-       printf("%s", tracer_priv->i++ ? ", " : "");
-       tracer_print_type(tracer_priv->elem_type, elem);
-       return SIDE_VISITOR_STATUS_OK;
+       tracer_print_elem(loc, NULL, priv);
 }
 
 static
-void tracer_print_vla_visitor(const struct side_type *type_desc, struct side_arg_vla_visitor *vla_visitor)
+void tracer_print_dynamic_null(const struct side_arg *item,
+               void *priv __attribute__((unused)))
 {
-       void *app_ctx;
-       enum side_visitor_status status;
-       struct tracer_visitor_priv tracer_priv = {
-               .elem_type = side_ptr_get(type_desc->u.side_vla_visitor.elem_type),
-               .i = 0,
-       };
-       const struct side_tracer_visitor_ctx tracer_ctx = {
-               .write_elem = tracer_write_elem_cb,
-               .priv = &tracer_priv,
-       };
-       side_visitor_func func;
-
-       if (!vla_visitor)
-               abort();
-       app_ctx = side_ptr_get(vla_visitor->app_ctx);
-       print_attributes("attr", ":", side_ptr_get(type_desc->u.side_vla_visitor.attr), type_desc->u.side_vla_visitor.nr_attr);
-       printf("%s", type_desc->u.side_vla_visitor.nr_attr ? ", " : "");
-       printf("elements: ");
-       printf("[ ");
-       func = side_ptr_get(type_desc->u.side_vla_visitor.visitor);
-       status = func(&tracer_ctx, app_ctx);
-       switch (status) {
-       case SIDE_VISITOR_STATUS_OK:
-               break;
-       case SIDE_VISITOR_STATUS_ERROR:
-               fprintf(stderr, "ERROR: Visitor error\n");
-               abort();
-       }
-       printf(" ]");
+       tracer_print_type_header("::", side_ptr_get(item->u.side_dynamic.side_null.attr),
+               item->u.side_dynamic.side_null.nr_attr);
+       printf("<NULL TYPE>");
 }
 
 static
-void tracer_print_dynamic_struct(const struct side_arg_dynamic_struct *dynamic_struct)
+void tracer_print_dynamic_bool(const struct side_arg *item,
+               void *priv __attribute__((unused)))
 {
-       const struct side_arg_dynamic_field *fields = side_ptr_get(dynamic_struct->fields);
-       uint32_t i, len = dynamic_struct->len;
-
-       print_attributes("attr", "::", side_ptr_get(dynamic_struct->attr), dynamic_struct->nr_attr);
-       printf("%s", dynamic_struct->nr_attr ? ", " : "");
-       printf("fields:: ");
-       printf("[ ");
-       for (i = 0; i < len; i++) {
-               printf("%s", i ? ", " : "");
-               printf("%s:: ", side_ptr_get(fields[i].field_name));
-               tracer_print_dynamic(&fields[i].elem);
-       }
-       printf(" ]");
+       tracer_print_type_bool("::", &item->u.side_dynamic.side_bool.type, &item->u.side_dynamic.side_bool.value, 0);
 }
 
-struct tracer_dynamic_struct_visitor_priv {
-       int i;
-};
-
 static
-enum side_visitor_status tracer_dynamic_struct_write_elem_cb(
-                       const struct side_tracer_dynamic_struct_visitor_ctx *tracer_ctx,
-                       const struct side_arg_dynamic_field *dynamic_field)
+void tracer_print_dynamic_integer(const struct side_arg *item,
+               void *priv __attribute__((unused)))
 {
-       struct tracer_dynamic_struct_visitor_priv *tracer_priv =
-               (struct tracer_dynamic_struct_visitor_priv *) tracer_ctx->priv;
-
-       printf("%s", tracer_priv->i++ ? ", " : "");
-       printf("%s:: ", side_ptr_get(dynamic_field->field_name));
-       tracer_print_dynamic(&dynamic_field->elem);
-       return SIDE_VISITOR_STATUS_OK;
+       tracer_print_type_integer("::", &item->u.side_dynamic.side_integer.type, &item->u.side_dynamic.side_integer.value, 0,
+                       TRACER_DISPLAY_BASE_10);
 }
 
 static
-void tracer_print_dynamic_struct_visitor(const struct side_arg *item)
+void tracer_print_dynamic_byte(const struct side_arg *item,
+               void *priv __attribute__((unused)))
 {
-       struct side_arg_dynamic_struct_visitor *dynamic_struct_visitor;
-       struct tracer_dynamic_struct_visitor_priv tracer_priv = {
-               .i = 0,
-       };
-       const struct side_tracer_dynamic_struct_visitor_ctx tracer_ctx = {
-               .write_field = tracer_dynamic_struct_write_elem_cb,
-               .priv = &tracer_priv,
-       };
-       enum side_visitor_status status;
-       void *app_ctx;
-
-       dynamic_struct_visitor = side_ptr_get(item->u.side_dynamic.side_dynamic_struct_visitor);
-       if (!dynamic_struct_visitor)
-               abort();
-       app_ctx = side_ptr_get(dynamic_struct_visitor->app_ctx);
-       print_attributes("attr", "::", side_ptr_get(dynamic_struct_visitor->attr), dynamic_struct_visitor->nr_attr);
-       printf("%s", dynamic_struct_visitor->nr_attr ? ", " : "");
-       printf("fields:: ");
-       printf("[ ");
-       status = side_ptr_get(dynamic_struct_visitor->visitor)(&tracer_ctx, app_ctx);
-       switch (status) {
-       case SIDE_VISITOR_STATUS_OK:
-               break;
-       case SIDE_VISITOR_STATUS_ERROR:
-               fprintf(stderr, "ERROR: Visitor error\n");
-               abort();
-       }
-       printf(" ]");
+       tracer_print_type_header("::", side_ptr_get(item->u.side_dynamic.side_byte.type.attr), item->u.side_dynamic.side_byte.type.nr_attr);
+       printf("0x%" PRIx8, item->u.side_dynamic.side_byte.value);
 }
 
 static
-void tracer_print_dynamic_vla(const struct side_arg_dynamic_vla *vla)
+void tracer_print_dynamic_pointer(const struct side_arg *item,
+               void *priv __attribute__((unused)))
 {
-       const struct side_arg *sav = side_ptr_get(vla->sav);
-       uint32_t i, side_sav_len = vla->len;
+       tracer_print_type_integer("::", &item->u.side_dynamic.side_integer.type, &item->u.side_dynamic.side_integer.value, 0,
+                       TRACER_DISPLAY_BASE_16);
+}
 
-       print_attributes("attr", "::", side_ptr_get(vla->attr), vla->nr_attr);
-       printf("%s", vla->nr_attr ? ", " : "");
-       printf("elements:: ");
-       printf("[ ");
-       for (i = 0; i < side_sav_len; i++) {
-               printf("%s", i ? ", " : "");
-               tracer_print_dynamic(&sav[i]);
-       }
-       printf(" ]");
+static
+void tracer_print_dynamic_float(const struct side_arg *item,
+               void *priv __attribute__((unused)))
+{
+       tracer_print_type_float("::", &item->u.side_dynamic.side_float.type,
+                       &item->u.side_dynamic.side_float.value);
 }
 
-struct tracer_dynamic_vla_visitor_priv {
-       int i;
-};
+static
+void tracer_print_dynamic_string(const struct side_arg *item,
+               void *priv __attribute__((unused)))
+{
+       tracer_print_type_header("::", side_ptr_get(item->u.side_dynamic.side_string.type.attr), item->u.side_dynamic.side_string.type.nr_attr);
+       tracer_print_type_string((const char *)(uintptr_t) item->u.side_dynamic.side_string.value,
+                       item->u.side_dynamic.side_string.type.unit_size,
+                       side_enum_get(item->u.side_dynamic.side_string.type.byte_order), NULL);
+}
 
 static
-enum side_visitor_status tracer_dynamic_vla_write_elem_cb(
-                       const struct side_tracer_visitor_ctx *tracer_ctx,
-                       const struct side_arg *elem)
+void tracer_print_dynamic_struct(enum side_type_visitor_location loc,
+       const struct side_arg_dynamic_struct *dynamic_struct,
+       void *priv)
 {
-       struct tracer_dynamic_vla_visitor_priv *tracer_priv =
-               (struct tracer_dynamic_vla_visitor_priv *) tracer_ctx->priv;
+       struct print_ctx *ctx = (struct print_ctx *) priv;
 
-       printf("%s", tracer_priv->i++ ? ", " : "");
-       tracer_print_dynamic(elem);
-       return SIDE_VISITOR_STATUS_OK;
+       switch (loc) {
+       case SIDE_TYPE_VISITOR_BEFORE:
+               print_attributes("attr", "::", side_ptr_get(dynamic_struct->attr), dynamic_struct->nr_attr);
+               printf("%s", dynamic_struct->nr_attr ? ", " : "");
+               printf("fields:: {");
+               push_nesting(ctx);
+               break;
+       case SIDE_TYPE_VISITOR_AFTER:
+               pop_nesting(ctx);
+               printf(" }");
+               break;
+       }
 }
 
 static
-void tracer_print_dynamic_vla_visitor(const struct side_arg *item)
+void tracer_print_dynamic_struct_visitor(enum side_type_visitor_location loc,
+       const struct side_arg *item,
+       void *priv)
 {
-       struct side_arg_dynamic_vla_visitor *dynamic_vla_visitor;
-       struct tracer_dynamic_vla_visitor_priv tracer_priv = {
-               .i = 0,
-       };
-       const struct side_tracer_visitor_ctx tracer_ctx = {
-               .write_elem = tracer_dynamic_vla_write_elem_cb,
-               .priv = &tracer_priv,
-       };
-       enum side_visitor_status status;
-       void *app_ctx;
+       struct side_arg_dynamic_struct_visitor *dynamic_struct_visitor;
+       struct print_ctx *ctx = (struct print_ctx *) priv;
 
-       dynamic_vla_visitor = side_ptr_get(item->u.side_dynamic.side_dynamic_vla_visitor);
-       if (!dynamic_vla_visitor)
-               abort();
-       app_ctx = side_ptr_get(dynamic_vla_visitor->app_ctx);
-       print_attributes("attr", "::", side_ptr_get(dynamic_vla_visitor->attr), dynamic_vla_visitor->nr_attr);
-       printf("%s", dynamic_vla_visitor->nr_attr ? ", " : "");
-       printf("elements:: ");
-       printf("[ ");
-       status = side_ptr_get(dynamic_vla_visitor->visitor)(&tracer_ctx, app_ctx);
-       switch (status) {
-       case SIDE_VISITOR_STATUS_OK:
-               break;
-       case SIDE_VISITOR_STATUS_ERROR:
-               fprintf(stderr, "ERROR: Visitor error\n");
+       dynamic_struct_visitor = side_ptr_get(item->u.side_dynamic.side_dynamic_struct_visitor);
+       if (!dynamic_struct_visitor)
                abort();
+
+       switch (loc) {
+       case SIDE_TYPE_VISITOR_BEFORE:
+               print_attributes("attr", "::", side_ptr_get(dynamic_struct_visitor->attr), dynamic_struct_visitor->nr_attr);
+               printf("%s", dynamic_struct_visitor->nr_attr ? ", " : "");
+               printf("fields:: {");
+               push_nesting(ctx);
+               break;
+       case SIDE_TYPE_VISITOR_AFTER:
+               pop_nesting(ctx);
+               printf(" }");
+               break;
        }
-       printf(" ]");
 }
 
 static
-void tracer_print_dynamic(const struct side_arg *item)
+void tracer_print_dynamic_vla(enum side_type_visitor_location loc,
+       const struct side_arg_dynamic_vla *dynamic_vla,
+       void *priv)
 {
-       printf("{ ");
-       switch (side_enum_get(item->type)) {
-               /* Dynamic basic types */
-       case SIDE_TYPE_DYNAMIC_NULL:
-               tracer_print_type_header("::", side_ptr_get(item->u.side_dynamic.side_null.attr),
-                       item->u.side_dynamic.side_null.nr_attr);
-               printf("<NULL TYPE>");
-               break;
-       case SIDE_TYPE_DYNAMIC_BOOL:
-               tracer_print_type_bool("::", &item->u.side_dynamic.side_bool.type, &item->u.side_dynamic.side_bool.value, 0);
-               break;
-       case SIDE_TYPE_DYNAMIC_INTEGER:
-               tracer_print_type_integer("::", &item->u.side_dynamic.side_integer.type, &item->u.side_dynamic.side_integer.value, 0,
-                               TRACER_DISPLAY_BASE_10);
-               break;
-       case SIDE_TYPE_DYNAMIC_BYTE:
-               tracer_print_type_header("::", side_ptr_get(item->u.side_dynamic.side_byte.type.attr), item->u.side_dynamic.side_byte.type.nr_attr);
-               printf("0x%" PRIx8, item->u.side_dynamic.side_byte.value);
-               break;
-       case SIDE_TYPE_DYNAMIC_POINTER:
-               tracer_print_type_integer("::", &item->u.side_dynamic.side_integer.type, &item->u.side_dynamic.side_integer.value, 0,
-                               TRACER_DISPLAY_BASE_16);
-               break;
-       case SIDE_TYPE_DYNAMIC_FLOAT:
-               tracer_print_type_float("::", &item->u.side_dynamic.side_float.type,
-                                       &item->u.side_dynamic.side_float.value);
-               break;
-       case SIDE_TYPE_DYNAMIC_STRING:
-               tracer_print_type_header("::", side_ptr_get(item->u.side_dynamic.side_string.type.attr), item->u.side_dynamic.side_string.type.nr_attr);
-               tracer_print_string((const char *)(uintptr_t) item->u.side_dynamic.side_string.value,
-                               item->u.side_dynamic.side_string.type.unit_size,
-                               side_enum_get(item->u.side_dynamic.side_string.type.byte_order), NULL);
-               break;
+       struct print_ctx *ctx = (struct print_ctx *) priv;
 
-               /* Dynamic compound types */
-       case SIDE_TYPE_DYNAMIC_STRUCT:
-               tracer_print_dynamic_struct(side_ptr_get(item->u.side_dynamic.side_dynamic_struct));
-               break;
-       case SIDE_TYPE_DYNAMIC_STRUCT_VISITOR:
-               tracer_print_dynamic_struct_visitor(item);
-               break;
-       case SIDE_TYPE_DYNAMIC_VLA:
-               tracer_print_dynamic_vla(side_ptr_get(item->u.side_dynamic.side_dynamic_vla));
+       switch (loc) {
+       case SIDE_TYPE_VISITOR_BEFORE:
+               print_attributes("attr", "::", side_ptr_get(dynamic_vla->attr), dynamic_vla->nr_attr);
+               printf("%s", dynamic_vla->nr_attr ? ", " : "");
+               printf("elements:: [");
+               push_nesting(ctx);
                break;
-       case SIDE_TYPE_DYNAMIC_VLA_VISITOR:
-               tracer_print_dynamic_vla_visitor(item);
+       case SIDE_TYPE_VISITOR_AFTER:
+               pop_nesting(ctx);
+               printf(" ]");
                break;
-       default:
-               fprintf(stderr, "<UNKNOWN TYPE>\n");
-               abort();
        }
-       printf(" }");
 }
 
 static
-void tracer_print_static_fields(const struct side_event_description *desc,
-               const struct side_arg_vec *side_arg_vec,
-               uint32_t *nr_items, void *caller_addr)
+void tracer_print_dynamic_vla_visitor(enum side_type_visitor_location loc,
+       const struct side_arg *item,
+       void *priv)
 {
-       const struct side_arg *sav = side_ptr_get(side_arg_vec->sav);
-       uint32_t i, side_sav_len = side_arg_vec->len;
+       struct side_arg_dynamic_vla_visitor *dynamic_vla_visitor;
+       struct print_ctx *ctx = (struct print_ctx *) priv;
 
-       printf("caller: [%p], provider: %s, event: %s", caller_addr,
-               side_ptr_get(desc->provider_name),
-               side_ptr_get(desc->event_name));
-       if (desc->nr_fields != side_sav_len) {
-               fprintf(stderr, "ERROR: number of fields mismatch between description and arguments\n");
+       dynamic_vla_visitor = side_ptr_get(item->u.side_dynamic.side_dynamic_vla_visitor);
+       if (!dynamic_vla_visitor)
                abort();
-       }
-       print_attributes(", attr", ":", side_ptr_get(desc->attr), desc->nr_attr);
-       printf("%s", side_sav_len ? ", fields: [ " : "");
-       for (i = 0; i < side_sav_len; i++) {
-               printf("%s", i ? ", " : "");
-               tracer_print_field(&side_ptr_get(desc->fields)[i], &sav[i]);
-       }
-       if (nr_items)
-               *nr_items = i;
-       if (side_sav_len)
+
+       switch (loc) {
+       case SIDE_TYPE_VISITOR_BEFORE:
+               print_attributes("attr", "::", side_ptr_get(dynamic_vla_visitor->attr), dynamic_vla_visitor->nr_attr);
+               printf("%s", dynamic_vla_visitor->nr_attr ? ", " : "");
+               printf("elements:: [");
+               push_nesting(ctx);
+               break;
+       case SIDE_TYPE_VISITOR_AFTER:
+               pop_nesting(ctx);
                printf(" ]");
+               break;
+       }
 }
 
+static struct side_type_visitor type_visitor = {
+       .event_func = tracer_print_event,
+       .static_fields_func = tracer_print_static_fields,
+       .variadic_fields_func = tracer_print_variadic_fields,
+
+       /* Stack-copy basic types. */
+       .field_func = tracer_print_field,
+       .elem_func = tracer_print_elem,
+       .null_type_func = tracer_print_null,
+       .bool_type_func = tracer_print_bool,
+       .integer_type_func = tracer_print_integer,
+       .byte_type_func = tracer_print_byte,
+       .pointer_type_func = tracer_print_pointer,
+       .float_type_func = tracer_print_float,
+       .string_type_func = tracer_print_string,
+
+       /* Stack-copy compound types. */
+       .struct_type_func = tracer_print_struct,
+       .array_type_func = tracer_print_array,
+       .vla_type_func = tracer_print_vla,
+       .vla_visitor_type_func = tracer_print_vla_visitor,
+
+       /* Stack-copy enumeration types. */
+       .enum_type_func = tracer_print_enum,
+       .enum_bitmap_type_func = tracer_print_enum_bitmap,
+
+       /* Gather basic types. */
+       .gather_bool_type_func = tracer_print_gather_bool,
+       .gather_byte_type_func = tracer_print_gather_byte,
+       .gather_integer_type_func = tracer_print_gather_integer,
+       .gather_pointer_type_func = tracer_print_gather_pointer,
+       .gather_float_type_func = tracer_print_gather_float,
+       .gather_string_type_func = tracer_print_gather_string,
+
+       /* Gather compound types. */
+       .gather_struct_type_func = tracer_print_gather_struct,
+       .gather_array_type_func = tracer_print_gather_array,
+       .gather_vla_type_func = tracer_print_gather_vla,
+
+       /* Gather enumeration types. */
+       .gather_enum_type_func = tracer_print_gather_enum,
+
+       /* Dynamic basic types. */
+       .dynamic_field_func = tracer_print_dynamic_field,
+       .dynamic_elem_func = tracer_print_dynamic_elem,
+
+       .dynamic_null_func = tracer_print_dynamic_null,
+       .dynamic_bool_func = tracer_print_dynamic_bool,
+       .dynamic_integer_func = tracer_print_dynamic_integer,
+       .dynamic_byte_func = tracer_print_dynamic_byte,
+       .dynamic_pointer_func = tracer_print_dynamic_pointer,
+       .dynamic_float_func = tracer_print_dynamic_float,
+       .dynamic_string_func = tracer_print_dynamic_string,
+
+       /* Dynamic compound types. */
+       .dynamic_struct_func = tracer_print_dynamic_struct,
+       .dynamic_struct_visitor_func = tracer_print_dynamic_struct_visitor,
+       .dynamic_vla_func = tracer_print_dynamic_vla,
+       .dynamic_vla_visitor_func = tracer_print_dynamic_vla_visitor,
+};
+
 static
 void tracer_call(const struct side_event_description *desc,
                const struct side_arg_vec *side_arg_vec,
                void *priv __attribute__((unused)),
                void *caller_addr)
 {
-       uint32_t nr_fields = 0;
+       struct print_ctx ctx = {};
 
-       tracer_print_static_fields(desc, side_arg_vec, &nr_fields, caller_addr);
-       printf("\n");
+       type_visitor_event(&type_visitor, desc, side_arg_vec, NULL, caller_addr, &ctx);
 }
 
 static
@@ -2066,24 +1711,9 @@ void tracer_call_variadic(const struct side_event_description *desc,
                void *priv __attribute__((unused)),
                void *caller_addr)
 {
-       uint32_t nr_fields = 0, i, var_struct_len = var_struct->len;
-
-       tracer_print_static_fields(desc, side_arg_vec, &nr_fields, caller_addr);
+       struct print_ctx ctx = {};
 
-       if (side_unlikely(!(desc->flags & SIDE_EVENT_FLAG_VARIADIC))) {
-               fprintf(stderr, "ERROR: unexpected non-variadic event description\n");
-               abort();
-       }
-       print_attributes(", attr ", "::", side_ptr_get(var_struct->attr), var_struct->nr_attr);
-       printf("%s", var_struct_len ? ", fields:: [ " : "");
-       for (i = 0; i < var_struct_len; i++, nr_fields++) {
-               printf("%s", i ? ", " : "");
-               printf("%s:: ", side_ptr_get(side_ptr_get(var_struct->fields)[i].field_name));
-               tracer_print_dynamic(&side_ptr_get(var_struct->fields)[i].elem);
-       }
-       if (i)
-               printf(" ]");
-       printf("\n");
+       type_visitor_event(&type_visitor, desc, side_arg_vec, var_struct, caller_addr, &ctx);
 }
 
 static
diff --git a/src/visit-arg-vec.c b/src/visit-arg-vec.c
new file mode 100644 (file)
index 0000000..51fca8f
--- /dev/null
@@ -0,0 +1,1210 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright 2022-2024 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ */
+
+#include <string.h>
+
+#include "visit-arg-vec.h"
+
+union int_value {
+       uint64_t u[NR_SIDE_INTEGER128_SPLIT];
+       int64_t s[NR_SIDE_INTEGER128_SPLIT];
+};
+
+static
+void visit_dynamic_type(const struct side_type_visitor *type_visitor, const struct side_arg *dynamic_item, void *priv);
+
+static
+void visit_dynamic_elem(const struct side_type_visitor *type_visitor, const struct side_arg *dynamic_item, void *priv);
+
+static
+uint32_t visit_gather_type(const struct side_type_visitor *type_visitor, const struct side_type *type_desc, const void *ptr, void *priv);
+
+static
+uint32_t visit_gather_elem(const struct side_type_visitor *type_visitor, const struct side_type *type_desc, const void *ptr, void *priv);
+
+static
+void side_visit_type(const struct side_type_visitor *type_visitor, const struct side_type *type_desc, const struct side_arg *item, void *priv);
+
+static
+void side_visit_elem(const struct side_type_visitor *type_visitor, const struct side_type *type_desc, const struct side_arg *item, void *priv);
+
+static
+uint32_t type_visitor_gather_enum(const struct side_type_visitor *type_visitor, const struct side_type_gather *type_gather, const void *_ptr, void *priv);
+
+static
+uint32_t type_visitor_gather_struct(const struct side_type_visitor *type_visitor, const struct side_type_gather *type_gather, const void *_ptr, void *priv);
+
+static
+uint32_t type_visitor_gather_array(const struct side_type_visitor *type_visitor, const struct side_type_gather *type_gather, const void *_ptr, void *priv);
+
+static
+uint32_t type_visitor_gather_vla(const struct side_type_visitor *type_visitor, const struct side_type_gather *type_gather, const void *_ptr,
+               const void *_length_ptr, void *priv);
+
+static
+union int_value tracer_load_integer_value(const struct side_type_integer *type_integer,
+               const union side_integer_value *value,
+               uint16_t offset_bits, uint16_t *_len_bits)
+{
+       union int_value v = {};
+       uint16_t len_bits;
+       bool reverse_bo;
+
+       if (!type_integer->len_bits)
+               len_bits = type_integer->integer_size * CHAR_BIT;
+       else
+               len_bits = type_integer->len_bits;
+       if (len_bits + offset_bits > type_integer->integer_size * CHAR_BIT)
+               abort();
+       reverse_bo = side_enum_get(type_integer->byte_order) != SIDE_TYPE_BYTE_ORDER_HOST;
+       switch (type_integer->integer_size) {
+       case 1:
+               if (type_integer->signedness)
+                       v.s[SIDE_INTEGER128_SPLIT_LOW] = value->side_s8;
+               else
+                       v.u[SIDE_INTEGER128_SPLIT_LOW] = value->side_u8;
+               break;
+       case 2:
+               if (type_integer->signedness) {
+                       int16_t side_s16;
+
+                       side_s16 = value->side_s16;
+                       if (reverse_bo)
+                               side_s16 = side_bswap_16(side_s16);
+                       v.s[SIDE_INTEGER128_SPLIT_LOW] = side_s16;
+               } else {
+                       uint16_t side_u16;
+
+                       side_u16 = value->side_u16;
+                       if (reverse_bo)
+                               side_u16 = side_bswap_16(side_u16);
+                       v.u[SIDE_INTEGER128_SPLIT_LOW] = side_u16;
+               }
+               break;
+       case 4:
+               if (type_integer->signedness) {
+                       int32_t side_s32;
+
+                       side_s32 = value->side_s32;
+                       if (reverse_bo)
+                               side_s32 = side_bswap_32(side_s32);
+                       v.s[SIDE_INTEGER128_SPLIT_LOW] = side_s32;
+               } else {
+                       uint32_t side_u32;
+
+                       side_u32 = value->side_u32;
+                       if (reverse_bo)
+                               side_u32 = side_bswap_32(side_u32);
+                       v.u[SIDE_INTEGER128_SPLIT_LOW] = side_u32;
+               }
+               break;
+       case 8:
+               if (type_integer->signedness) {
+                       int64_t side_s64;
+
+                       side_s64 = value->side_s64;
+                       if (reverse_bo)
+                               side_s64 = side_bswap_64(side_s64);
+                       v.s[SIDE_INTEGER128_SPLIT_LOW] = side_s64;
+               } else {
+                       uint64_t side_u64;
+
+                       side_u64 = value->side_u64;
+                       if (reverse_bo)
+                               side_u64 = side_bswap_64(side_u64);
+                       v.u[SIDE_INTEGER128_SPLIT_LOW] = side_u64;
+               }
+               break;
+       case 16:
+               if (type_integer->signedness) {
+                       int64_t side_s64[NR_SIDE_INTEGER128_SPLIT];
+
+                       side_s64[SIDE_INTEGER128_SPLIT_LOW] = value->side_s128_split[SIDE_INTEGER128_SPLIT_LOW];
+                       side_s64[SIDE_INTEGER128_SPLIT_HIGH] = value->side_s128_split[SIDE_INTEGER128_SPLIT_HIGH];
+                       if (reverse_bo) {
+                               side_s64[SIDE_INTEGER128_SPLIT_LOW] = side_bswap_64(side_s64[SIDE_INTEGER128_SPLIT_LOW]);
+                               side_s64[SIDE_INTEGER128_SPLIT_HIGH] = side_bswap_64(side_s64[SIDE_INTEGER128_SPLIT_HIGH]);
+                               v.s[SIDE_INTEGER128_SPLIT_LOW] = side_s64[SIDE_INTEGER128_SPLIT_HIGH];
+                               v.s[SIDE_INTEGER128_SPLIT_HIGH] = side_s64[SIDE_INTEGER128_SPLIT_LOW];
+                       } else {
+                               v.s[SIDE_INTEGER128_SPLIT_LOW] = side_s64[SIDE_INTEGER128_SPLIT_LOW];
+                               v.s[SIDE_INTEGER128_SPLIT_HIGH] = side_s64[SIDE_INTEGER128_SPLIT_HIGH];
+                       }
+               } else {
+                       uint64_t side_u64[NR_SIDE_INTEGER128_SPLIT];
+
+                       side_u64[SIDE_INTEGER128_SPLIT_LOW] = value->side_u128_split[SIDE_INTEGER128_SPLIT_LOW];
+                       side_u64[SIDE_INTEGER128_SPLIT_HIGH] = value->side_u128_split[SIDE_INTEGER128_SPLIT_HIGH];
+                       if (reverse_bo) {
+                               side_u64[SIDE_INTEGER128_SPLIT_LOW] = side_bswap_64(side_u64[SIDE_INTEGER128_SPLIT_LOW]);
+                               side_u64[SIDE_INTEGER128_SPLIT_HIGH] = side_bswap_64(side_u64[SIDE_INTEGER128_SPLIT_HIGH]);
+                               v.u[SIDE_INTEGER128_SPLIT_LOW] = side_u64[SIDE_INTEGER128_SPLIT_HIGH];
+                               v.u[SIDE_INTEGER128_SPLIT_HIGH] = side_u64[SIDE_INTEGER128_SPLIT_LOW];
+                       } else {
+                               v.u[SIDE_INTEGER128_SPLIT_LOW] = side_u64[SIDE_INTEGER128_SPLIT_LOW];
+                               v.u[SIDE_INTEGER128_SPLIT_HIGH] = side_u64[SIDE_INTEGER128_SPLIT_HIGH];
+                       }
+               }
+               break;
+       default:
+               abort();
+       }
+       if (type_integer->integer_size <= 8) {
+               v.u[SIDE_INTEGER128_SPLIT_LOW] >>= offset_bits;
+               if (len_bits < 64) {
+                       v.u[SIDE_INTEGER128_SPLIT_LOW] &= (1ULL << len_bits) - 1;
+                       if (type_integer->signedness) {
+                               /* Sign-extend. */
+                               if (v.u[SIDE_INTEGER128_SPLIT_LOW] & (1ULL << (len_bits - 1))) {
+                                       v.u[SIDE_INTEGER128_SPLIT_LOW] |= ~((1ULL << len_bits) - 1);
+                                       v.u[SIDE_INTEGER128_SPLIT_HIGH] = ~0ULL;
+                               }
+                       }
+               }
+       } else {
+               //TODO: Implement 128-bit integer with len_bits != 128 or nonzero offset_bits
+               if (len_bits < 128 || offset_bits != 0)
+                       abort();
+       }
+       if (_len_bits)
+               *_len_bits = len_bits;
+       return v;
+}
+
+static
+void side_check_value_u64(union int_value v)
+{
+       if (v.u[SIDE_INTEGER128_SPLIT_HIGH]) {
+               fprintf(stderr, "Unexpected integer value\n");
+               abort();
+       }
+}
+
+/*
+ * return the size of the input string including the null terminator, in
+ * bytes.
+ */
+static
+size_t type_visitor_strlen(const void *p, uint8_t unit_size)
+{
+       size_t inbytesleft = 0;
+
+       switch (unit_size) {
+       case 1:
+       {
+               const char *str = p;
+
+               return strlen(str) + 1;
+       }
+       case 2:
+       {
+               const uint16_t *p16 = p;
+
+               for (; *p16; p16++)
+                       inbytesleft += 2;
+               return inbytesleft + 2;         /* Include 2-byte null terminator. */
+       }
+       case 4:
+       {
+               const uint32_t *p32 = p;
+
+               for (; *p32; p32++)
+                       inbytesleft += 4;
+               return inbytesleft + 4;         /* Include 4-byte null terminator. */
+       }
+       default:
+               fprintf(stderr, "Unknown string unit size %" PRIu8 "\n", unit_size);
+               abort();
+       }
+}
+
+static
+void side_visit_elem(const struct side_type_visitor *type_visitor, const struct side_type *type_desc, const struct side_arg *item, void *priv)
+{
+       if (type_visitor->elem_func)
+               type_visitor->elem_func(SIDE_TYPE_VISITOR_BEFORE, type_desc, priv);
+       side_visit_type(type_visitor, type_desc, item, priv);
+       if (type_visitor->elem_func)
+               type_visitor->elem_func(SIDE_TYPE_VISITOR_AFTER, type_desc, priv);
+}
+
+static
+void side_visit_field(const struct side_type_visitor *type_visitor, const struct side_event_field *item_desc, const struct side_arg *item, void *priv)
+{
+       if (type_visitor->field_func)
+               type_visitor->field_func(SIDE_TYPE_VISITOR_BEFORE, item_desc, priv);
+       side_visit_type(type_visitor, &item_desc->side_type, item, priv);
+       if (type_visitor->field_func)
+               type_visitor->field_func(SIDE_TYPE_VISITOR_AFTER, item_desc, priv);
+}
+
+static
+void type_visitor_struct(const struct side_type_visitor *type_visitor, const struct side_type *type_desc, const struct side_arg_vec *side_arg_vec, void *priv)
+{
+       const struct side_arg *sav = side_ptr_get(side_arg_vec->sav);
+       const struct side_type_struct *side_struct = side_ptr_get(type_desc->u.side_struct);
+       uint32_t i, side_sav_len = side_arg_vec->len;
+
+       if (side_struct->nr_fields != side_sav_len) {
+               fprintf(stderr, "ERROR: number of fields mismatch between description and arguments of structure\n");
+               abort();
+       }
+       if (type_visitor->struct_type_func)
+               type_visitor->struct_type_func(SIDE_TYPE_VISITOR_BEFORE, side_struct, side_arg_vec, priv);
+       for (i = 0; i < side_sav_len; i++)
+               side_visit_field(type_visitor, &side_ptr_get(side_struct->fields)[i], &sav[i], priv);
+       if (type_visitor->struct_type_func)
+               type_visitor->struct_type_func(SIDE_TYPE_VISITOR_AFTER, side_struct, side_arg_vec, priv);
+}
+
+static
+void type_visitor_variant(const struct side_type_visitor *type_visitor, const struct side_type *type_desc, const struct side_arg_variant *side_arg_variant, void *priv)
+{
+       const struct side_type_variant *side_type_variant = side_ptr_get(type_desc->u.side_variant);
+       const struct side_type *selector_type = &side_type_variant->selector;
+       union int_value v;
+       uint32_t i;
+
+       if (side_enum_get(selector_type->type) != side_enum_get(side_arg_variant->selector.type)) {
+               fprintf(stderr, "ERROR: Unexpected variant selector type\n");
+               abort();
+       }
+       switch (side_enum_get(selector_type->type)) {
+       case SIDE_TYPE_U8:
+       case SIDE_TYPE_U16:
+       case SIDE_TYPE_U32:
+       case SIDE_TYPE_U64:
+       case SIDE_TYPE_U128:
+       case SIDE_TYPE_S8:
+       case SIDE_TYPE_S16:
+       case SIDE_TYPE_S32:
+       case SIDE_TYPE_S64:
+       case SIDE_TYPE_S128:
+               break;
+       default:
+               fprintf(stderr, "ERROR: Expecting integer variant selector type\n");
+               abort();
+       }
+       v = tracer_load_integer_value(&selector_type->u.side_integer,
+                       &side_arg_variant->selector.u.side_static.integer_value, 0, NULL);
+       side_check_value_u64(v);
+       for (i = 0; i < side_type_variant->nr_options; i++) {
+               const struct side_variant_option *option = &side_ptr_get(side_type_variant->options)[i];
+
+               if (v.s[SIDE_INTEGER128_SPLIT_LOW] >= option->range_begin && v.s[SIDE_INTEGER128_SPLIT_LOW] <= option->range_end) {
+                       side_visit_type(type_visitor, &option->side_type, &side_arg_variant->option, priv);
+                       return;
+               }
+       }
+       fprintf(stderr, "ERROR: Variant selector value unknown %" PRId64 "\n", v.s[SIDE_INTEGER128_SPLIT_LOW]);
+       abort();
+}
+
+static
+void type_visitor_array(const struct side_type_visitor *type_visitor, const struct side_type *type_desc, const struct side_arg_vec *side_arg_vec, void *priv)
+{
+       const struct side_arg *sav = side_ptr_get(side_arg_vec->sav);
+       uint32_t i, side_sav_len = side_arg_vec->len;
+
+       if (type_desc->u.side_array.length != side_sav_len) {
+               fprintf(stderr, "ERROR: length mismatch between description and arguments of array\n");
+               abort();
+       }
+       if (type_visitor->array_type_func)
+               type_visitor->array_type_func(SIDE_TYPE_VISITOR_BEFORE, &type_desc->u.side_array, side_arg_vec, priv);
+       for (i = 0; i < side_sav_len; i++)
+               side_visit_elem(type_visitor, side_ptr_get(type_desc->u.side_array.elem_type), &sav[i], priv);
+       if (type_visitor->array_type_func)
+               type_visitor->array_type_func(SIDE_TYPE_VISITOR_AFTER, &type_desc->u.side_array, side_arg_vec, priv);
+}
+
+static
+void type_visitor_vla(const struct side_type_visitor *type_visitor, const struct side_type *type_desc, const struct side_arg_vec *side_arg_vec, void *priv)
+{
+       const struct side_arg *sav = side_ptr_get(side_arg_vec->sav);
+       uint32_t i, side_sav_len = side_arg_vec->len;
+
+       if (type_visitor->vla_type_func)
+               type_visitor->vla_type_func(SIDE_TYPE_VISITOR_BEFORE, &type_desc->u.side_vla, side_arg_vec, priv);
+       for (i = 0; i < side_sav_len; i++)
+               side_visit_elem(type_visitor, side_ptr_get(type_desc->u.side_vla.elem_type), &sav[i], priv);
+       if (type_visitor->vla_type_func)
+               type_visitor->vla_type_func(SIDE_TYPE_VISITOR_AFTER, &type_desc->u.side_vla, side_arg_vec, priv);
+}
+
+struct tracer_visitor_priv {
+       const struct side_type_visitor *type_visitor;
+       void *priv;
+       const struct side_type *elem_type;
+       int i;
+};
+
+static
+enum side_visitor_status tracer_write_elem_cb(const struct side_tracer_visitor_ctx *tracer_ctx,
+                       const struct side_arg *elem)
+{
+       struct tracer_visitor_priv *tracer_priv = (struct tracer_visitor_priv *) tracer_ctx->priv;
+
+       side_visit_elem(tracer_priv->type_visitor, tracer_priv->elem_type, elem, tracer_priv->priv);
+       return SIDE_VISITOR_STATUS_OK;
+}
+
+static
+void type_visitor_vla_visitor(const struct side_type_visitor *type_visitor, const struct side_type *type_desc, struct side_arg_vla_visitor *vla_visitor, void *priv)
+{
+       struct tracer_visitor_priv tracer_priv = {
+               .type_visitor = type_visitor,
+               .priv = priv,
+               .elem_type = side_ptr_get(type_desc->u.side_vla_visitor.elem_type),
+               .i = 0,
+       };
+       const struct side_tracer_visitor_ctx tracer_ctx = {
+               .write_elem = tracer_write_elem_cb,
+               .priv = &tracer_priv,
+       };
+       enum side_visitor_status status;
+       side_visitor_func func;
+       void *app_ctx;
+
+       if (!vla_visitor)
+               abort();
+       if (type_visitor->vla_visitor_type_func)
+               type_visitor->vla_visitor_type_func(SIDE_TYPE_VISITOR_BEFORE, &type_desc->u.side_vla_visitor, vla_visitor, priv);
+       app_ctx = side_ptr_get(vla_visitor->app_ctx);
+       func = side_ptr_get(type_desc->u.side_vla_visitor.visitor);
+       status = func(&tracer_ctx, app_ctx);
+       switch (status) {
+       case SIDE_VISITOR_STATUS_OK:
+               break;
+       case SIDE_VISITOR_STATUS_ERROR:
+               fprintf(stderr, "ERROR: Visitor error\n");
+               abort();
+       }
+       if (type_visitor->vla_visitor_type_func)
+               type_visitor->vla_visitor_type_func(SIDE_TYPE_VISITOR_AFTER, &type_desc->u.side_vla_visitor, vla_visitor, priv);
+}
+
+static
+const char *tracer_gather_access(enum side_type_gather_access_mode access_mode, const char *ptr)
+{
+       switch (access_mode) {
+       case SIDE_TYPE_GATHER_ACCESS_DIRECT:
+               return ptr;
+       case SIDE_TYPE_GATHER_ACCESS_POINTER:
+               /* Dereference pointer */
+               memcpy(&ptr, ptr, sizeof(const char *));
+               return ptr;
+       default:
+               abort();
+       }
+}
+
+static
+uint32_t tracer_gather_size(enum side_type_gather_access_mode access_mode, uint32_t len)
+{
+       switch (access_mode) {
+       case SIDE_TYPE_GATHER_ACCESS_DIRECT:
+               return len;
+       case SIDE_TYPE_GATHER_ACCESS_POINTER:
+               return sizeof(void *);
+       default:
+               abort();
+       }
+}
+
+static
+union int_value tracer_load_gather_integer_value(const struct side_type_gather_integer *side_integer,
+               const void *_ptr)
+{
+       enum side_type_gather_access_mode access_mode =
+               (enum side_type_gather_access_mode) side_integer->access_mode;
+       uint32_t integer_size_bytes = side_integer->type.integer_size;
+       const char *ptr = (const char *) _ptr;
+       union side_integer_value value;
+
+       ptr = tracer_gather_access(access_mode, ptr + side_integer->offset);
+       memcpy(&value, ptr, integer_size_bytes);
+       return tracer_load_integer_value(&side_integer->type, &value,
+                       side_integer->offset_bits, NULL);
+}
+
+static
+void visit_gather_field(const struct side_type_visitor *type_visitor, const struct side_event_field *field, const void *ptr, void *priv)
+{
+       if (type_visitor->field_func)
+               type_visitor->field_func(SIDE_TYPE_VISITOR_BEFORE, field, priv);
+       (void) visit_gather_type(type_visitor, &field->side_type, ptr, priv);
+       if (type_visitor->field_func)
+               type_visitor->field_func(SIDE_TYPE_VISITOR_AFTER, field, priv);
+}
+
+static
+uint32_t type_visitor_gather_struct(const struct side_type_visitor *type_visitor, const struct side_type_gather *type_gather, const void *_ptr, void *priv)
+{
+       enum side_type_gather_access_mode access_mode =
+               (enum side_type_gather_access_mode) type_gather->u.side_struct.access_mode;
+       const struct side_type_struct *side_struct = side_ptr_get(type_gather->u.side_struct.type);
+       const char *ptr = (const char *) _ptr;
+       uint32_t i;
+
+       if (type_visitor->gather_struct_type_func)
+               type_visitor->gather_struct_type_func(SIDE_TYPE_VISITOR_BEFORE, side_struct, priv);
+       ptr = tracer_gather_access(access_mode, ptr + type_gather->u.side_struct.offset);
+       for (i = 0; i < side_struct->nr_fields; i++)
+               visit_gather_field(type_visitor, &side_ptr_get(side_struct->fields)[i], ptr, priv);
+       if (type_visitor->gather_struct_type_func)
+               type_visitor->gather_struct_type_func(SIDE_TYPE_VISITOR_AFTER, side_struct, priv);
+       return tracer_gather_size(access_mode, type_gather->u.side_struct.size);
+}
+
+static
+uint32_t type_visitor_gather_array(const struct side_type_visitor *type_visitor, const struct side_type_gather *type_gather, const void *_ptr, void *priv)
+{
+       enum side_type_gather_access_mode access_mode =
+               (enum side_type_gather_access_mode) type_gather->u.side_array.access_mode;
+       const struct side_type_array *side_array = &type_gather->u.side_array.type;
+       const char *ptr = (const char *) _ptr, *orig_ptr;
+       uint32_t i;
+
+       if (type_visitor->gather_array_type_func)
+               type_visitor->gather_array_type_func(SIDE_TYPE_VISITOR_BEFORE, side_array, priv);
+       ptr = tracer_gather_access(access_mode, ptr + type_gather->u.side_array.offset);
+       orig_ptr = ptr;
+       for (i = 0; i < side_array->length; i++) {
+               const struct side_type *elem_type = side_ptr_get(side_array->elem_type);
+
+               switch (side_enum_get(elem_type->type)) {
+               case SIDE_TYPE_GATHER_VLA:
+                       fprintf(stderr, "<gather VLA only supported within gather structures>\n");
+                       abort();
+               default:
+                       break;
+               }
+               ptr += visit_gather_elem(type_visitor, elem_type, ptr, priv);
+       }
+       if (type_visitor->gather_array_type_func)
+               type_visitor->gather_array_type_func(SIDE_TYPE_VISITOR_AFTER, side_array, priv);
+       return tracer_gather_size(access_mode, ptr - orig_ptr);
+}
+
+static
+uint32_t type_visitor_gather_vla(const struct side_type_visitor *type_visitor, const struct side_type_gather *type_gather, const void *_ptr, const void *_length_ptr, void *priv)
+{
+       enum side_type_gather_access_mode access_mode =
+               (enum side_type_gather_access_mode) type_gather->u.side_vla.access_mode;
+       const struct side_type_vla *side_vla = &type_gather->u.side_vla.type;
+       const struct side_type *length_type = side_ptr_get(type_gather->u.side_vla.length_type);
+       const char *ptr = (const char *) _ptr, *orig_ptr;
+       const char *length_ptr = (const char *) _length_ptr;
+       union int_value v = {};
+       uint32_t i, length;
+
+       /* Access length */
+       switch (side_enum_get(length_type->type)) {
+       case SIDE_TYPE_GATHER_INTEGER:
+               break;
+       default:
+               fprintf(stderr, "<gather VLA expects integer gather length type>\n");
+               abort();
+       }
+       v = tracer_load_gather_integer_value(&length_type->u.side_gather.u.side_integer,
+                                       length_ptr);
+       if (v.u[SIDE_INTEGER128_SPLIT_HIGH] || v.u[SIDE_INTEGER128_SPLIT_LOW] > UINT32_MAX) {
+               fprintf(stderr, "Unexpected vla length value\n");
+               abort();
+       }
+       length = (uint32_t) v.u[SIDE_INTEGER128_SPLIT_LOW];
+       if (type_visitor->gather_vla_type_func)
+               type_visitor->gather_vla_type_func(SIDE_TYPE_VISITOR_BEFORE, side_vla, length, priv);
+       ptr = tracer_gather_access(access_mode, ptr + type_gather->u.side_vla.offset);
+       orig_ptr = ptr;
+       for (i = 0; i < length; i++) {
+               const struct side_type *elem_type = side_ptr_get(side_vla->elem_type);
+
+               switch (side_enum_get(elem_type->type)) {
+               case SIDE_TYPE_GATHER_VLA:
+                       fprintf(stderr, "<gather VLA only supported within gather structures>\n");
+                       abort();
+               default:
+                       break;
+               }
+               ptr += visit_gather_elem(type_visitor, elem_type, ptr, priv);
+       }
+       if (type_visitor->gather_vla_type_func)
+               type_visitor->gather_vla_type_func(SIDE_TYPE_VISITOR_AFTER, side_vla, length, priv);
+       return tracer_gather_size(access_mode, ptr - orig_ptr);
+}
+
+static
+uint32_t type_visitor_gather_bool(const struct side_type_visitor *type_visitor, const struct side_type_gather *type_gather, const void *_ptr, void *priv)
+{
+       enum side_type_gather_access_mode access_mode =
+               (enum side_type_gather_access_mode) type_gather->u.side_bool.access_mode;
+       uint32_t bool_size_bytes = type_gather->u.side_bool.type.bool_size;
+       const char *ptr = (const char *) _ptr;
+       union side_bool_value value;
+
+       switch (bool_size_bytes) {
+       case 1:
+       case 2:
+       case 4:
+       case 8:
+               break;
+       default:
+               abort();
+       }
+       ptr = tracer_gather_access(access_mode, ptr + type_gather->u.side_bool.offset);
+       memcpy(&value, ptr, bool_size_bytes);
+       if (type_visitor->gather_bool_type_func)
+               type_visitor->gather_bool_type_func(&type_gather->u.side_bool, &value, priv);
+       return tracer_gather_size(access_mode, bool_size_bytes);
+}
+
+static
+uint32_t type_visitor_gather_byte(const struct side_type_visitor *type_visitor, const struct side_type_gather *type_gather, const void *_ptr, void *priv)
+{
+       enum side_type_gather_access_mode access_mode =
+               (enum side_type_gather_access_mode) type_gather->u.side_byte.access_mode;
+       const char *ptr = (const char *) _ptr;
+       uint8_t value;
+
+       ptr = tracer_gather_access(access_mode, ptr + type_gather->u.side_byte.offset);
+       memcpy(&value, ptr, 1);
+       if (type_visitor->gather_byte_type_func)
+               type_visitor->gather_byte_type_func(&type_gather->u.side_byte, &value, priv);
+       return tracer_gather_size(access_mode, 1);
+}
+
+static
+uint32_t type_visitor_gather_integer(const struct side_type_visitor *type_visitor, const struct side_type_gather *type_gather, const void *_ptr,
+               enum side_type_label integer_type, void *priv)
+{
+       enum side_type_gather_access_mode access_mode =
+               (enum side_type_gather_access_mode) type_gather->u.side_integer.access_mode;
+       uint32_t integer_size_bytes = type_gather->u.side_integer.type.integer_size;
+       const char *ptr = (const char *) _ptr;
+       union side_integer_value value;
+
+       switch (integer_size_bytes) {
+       case 1:
+       case 2:
+       case 4:
+       case 8:
+       case 16:
+               break;
+       default:
+               abort();
+       }
+       ptr = tracer_gather_access(access_mode, ptr + type_gather->u.side_integer.offset);
+       memcpy(&value, ptr, integer_size_bytes);
+       switch (integer_type) {
+       case SIDE_TYPE_GATHER_INTEGER:
+               if (type_visitor->gather_integer_type_func)
+                       type_visitor->gather_integer_type_func(&type_gather->u.side_integer, &value, priv);
+               break;
+       case SIDE_TYPE_GATHER_POINTER:
+               if (type_visitor->gather_pointer_type_func)
+                       type_visitor->gather_pointer_type_func(&type_gather->u.side_integer, &value, priv);
+               break;
+       default:
+               fprintf(stderr, "Unexpected integer type\n");
+               abort();
+       }
+       return tracer_gather_size(access_mode, integer_size_bytes);
+}
+
+static
+uint32_t type_visitor_gather_float(const struct side_type_visitor *type_visitor, const struct side_type_gather *type_gather, const void *_ptr, void *priv)
+{
+       enum side_type_gather_access_mode access_mode =
+               (enum side_type_gather_access_mode) type_gather->u.side_float.access_mode;
+       uint32_t float_size_bytes = type_gather->u.side_float.type.float_size;
+       const char *ptr = (const char *) _ptr;
+       union side_float_value value;
+
+       switch (float_size_bytes) {
+       case 2:
+       case 4:
+       case 8:
+       case 16:
+               break;
+       default:
+               abort();
+       }
+       ptr = tracer_gather_access(access_mode, ptr + type_gather->u.side_float.offset);
+       memcpy(&value, ptr, float_size_bytes);
+       if (type_visitor->gather_float_type_func)
+               type_visitor->gather_float_type_func(&type_gather->u.side_float, &value, priv);
+       return tracer_gather_size(access_mode, float_size_bytes);
+}
+
+static
+uint32_t type_visitor_gather_string(const struct side_type_visitor *type_visitor, const struct side_type_gather *type_gather, const void *_ptr, void *priv)
+{
+
+       enum side_type_gather_access_mode access_mode =
+               (enum side_type_gather_access_mode) type_gather->u.side_string.access_mode;
+       enum side_type_label_byte_order byte_order = side_enum_get(type_gather->u.side_string.type.byte_order);
+       uint8_t unit_size = type_gather->u.side_string.type.unit_size;
+       const char *ptr = (const char *) _ptr;
+       size_t string_len = 0;
+
+       ptr = tracer_gather_access(access_mode, ptr + type_gather->u.side_string.offset);
+       if (ptr)
+               string_len = type_visitor_strlen(ptr, unit_size);
+       if (type_visitor->gather_string_type_func)
+               type_visitor->gather_string_type_func(&type_gather->u.side_string, ptr, unit_size,
+                               byte_order, string_len, priv);
+       return tracer_gather_size(access_mode, string_len);
+}
+
+static
+uint32_t visit_gather_type(const struct side_type_visitor *type_visitor, const struct side_type *type_desc, const void *ptr, void *priv)
+{
+       uint32_t len;
+
+       switch (side_enum_get(type_desc->type)) {
+               /* Gather basic types */
+       case SIDE_TYPE_GATHER_BOOL:
+               len = type_visitor_gather_bool(type_visitor, &type_desc->u.side_gather, ptr, priv);
+               break;
+       case SIDE_TYPE_GATHER_INTEGER:
+               len = type_visitor_gather_integer(type_visitor, &type_desc->u.side_gather, ptr, SIDE_TYPE_GATHER_INTEGER, priv);
+               break;
+       case SIDE_TYPE_GATHER_BYTE:
+               len = type_visitor_gather_byte(type_visitor, &type_desc->u.side_gather, ptr, priv);
+               break;
+       case SIDE_TYPE_GATHER_POINTER:
+               len = type_visitor_gather_integer(type_visitor, &type_desc->u.side_gather, ptr, SIDE_TYPE_GATHER_POINTER, priv);
+               break;
+       case SIDE_TYPE_GATHER_FLOAT:
+               len = type_visitor_gather_float(type_visitor, &type_desc->u.side_gather, ptr, priv);
+               break;
+       case SIDE_TYPE_GATHER_STRING:
+               len = type_visitor_gather_string(type_visitor, &type_desc->u.side_gather, ptr, priv);
+               break;
+
+               /* Gather enumeration types */
+       case SIDE_TYPE_GATHER_ENUM:
+               len = type_visitor_gather_enum(type_visitor, &type_desc->u.side_gather, ptr, priv);
+               break;
+
+               /* Gather compound types */
+       case SIDE_TYPE_GATHER_STRUCT:
+               len = type_visitor_gather_struct(type_visitor, &type_desc->u.side_gather, ptr, priv);
+               break;
+       case SIDE_TYPE_GATHER_ARRAY:
+               len = type_visitor_gather_array(type_visitor, &type_desc->u.side_gather, ptr, priv);
+               break;
+       case SIDE_TYPE_GATHER_VLA:
+               len = type_visitor_gather_vla(type_visitor, &type_desc->u.side_gather, ptr, ptr, priv);
+               break;
+       default:
+               fprintf(stderr, "<UNKNOWN GATHER TYPE>");
+               abort();
+       }
+       return len;
+}
+
+static
+uint32_t visit_gather_elem(const struct side_type_visitor *type_visitor, const struct side_type *type_desc, const void *ptr, void *priv)
+{
+       uint32_t len;
+
+       if (type_visitor->elem_func)
+               type_visitor->elem_func(SIDE_TYPE_VISITOR_BEFORE, type_desc, priv);
+       len = visit_gather_type(type_visitor, type_desc, ptr, priv);
+       if (type_visitor->elem_func)
+               type_visitor->elem_func(SIDE_TYPE_VISITOR_AFTER, type_desc, priv);
+       return len;
+}
+
+static
+uint32_t type_visitor_gather_enum(const struct side_type_visitor *type_visitor, const struct side_type_gather *type_gather, const void *_ptr, void *priv)
+{
+       const struct side_type *enum_elem_type = side_ptr_get(type_gather->u.side_enum.elem_type);
+       const struct side_type_gather_integer *side_integer = &enum_elem_type->u.side_gather.u.side_integer;
+       enum side_type_gather_access_mode access_mode =
+               (enum side_type_gather_access_mode) side_integer->access_mode;
+       uint32_t integer_size_bytes = side_integer->type.integer_size;
+       const char *ptr = (const char *) _ptr;
+       union side_integer_value value;
+
+       switch (integer_size_bytes) {
+       case 1:
+       case 2:
+       case 4:
+       case 8:
+       case 16:
+               break;
+       default:
+               abort();
+       }
+       ptr = tracer_gather_access(access_mode, ptr + side_integer->offset);
+       memcpy(&value, ptr, integer_size_bytes);
+       if (type_visitor->gather_enum_type_func)
+               type_visitor->gather_enum_type_func(&type_gather->u.side_enum, &value, priv);
+       return tracer_gather_size(access_mode, integer_size_bytes);
+}
+
+static
+void visit_dynamic_field(const struct side_type_visitor *type_visitor, const struct side_arg_dynamic_field *field, void *priv)
+{
+       if (type_visitor->dynamic_field_func)
+               type_visitor->dynamic_field_func(SIDE_TYPE_VISITOR_BEFORE, field, priv);
+       visit_dynamic_type(type_visitor, &field->elem, priv);
+       if (type_visitor->dynamic_field_func)
+               type_visitor->dynamic_field_func(SIDE_TYPE_VISITOR_AFTER, field, priv);
+}
+
+static
+void type_visitor_dynamic_struct(const struct side_type_visitor *type_visitor, const struct side_arg_dynamic_struct *dynamic_struct, void *priv)
+{
+       const struct side_arg_dynamic_field *fields = side_ptr_get(dynamic_struct->fields);
+       uint32_t i, len = dynamic_struct->len;
+
+       if (type_visitor->dynamic_struct_func)
+               type_visitor->dynamic_struct_func(SIDE_TYPE_VISITOR_BEFORE, dynamic_struct, priv);
+       for (i = 0; i < len; i++)
+               visit_dynamic_field(type_visitor, &fields[i], priv);
+       if (type_visitor->dynamic_struct_func)
+               type_visitor->dynamic_struct_func(SIDE_TYPE_VISITOR_AFTER, dynamic_struct, priv);
+}
+
+struct tracer_dynamic_struct_visitor_priv {
+       const struct side_type_visitor *type_visitor;
+       void *priv;
+       int i;
+};
+
+static
+enum side_visitor_status tracer_dynamic_struct_write_elem_cb(
+                       const struct side_tracer_dynamic_struct_visitor_ctx *tracer_ctx,
+                       const struct side_arg_dynamic_field *dynamic_field)
+{
+       struct tracer_dynamic_struct_visitor_priv *tracer_priv =
+               (struct tracer_dynamic_struct_visitor_priv *) tracer_ctx->priv;
+
+       visit_dynamic_field(tracer_priv->type_visitor, dynamic_field, tracer_priv->priv);
+       return SIDE_VISITOR_STATUS_OK;
+}
+
+static
+void type_visitor_dynamic_struct_visitor(const struct side_type_visitor *type_visitor, const struct side_arg *item, void *priv)
+{
+       struct side_arg_dynamic_struct_visitor *dynamic_struct_visitor;
+       struct tracer_dynamic_struct_visitor_priv tracer_priv = {
+               .type_visitor = type_visitor,
+               .priv = priv,
+               .i = 0,
+       };
+       const struct side_tracer_dynamic_struct_visitor_ctx tracer_ctx = {
+               .write_field = tracer_dynamic_struct_write_elem_cb,
+               .priv = &tracer_priv,
+       };
+       enum side_visitor_status status;
+       void *app_ctx;
+
+       if (type_visitor->dynamic_struct_visitor_func)
+               type_visitor->dynamic_struct_visitor_func(SIDE_TYPE_VISITOR_BEFORE, item, priv);
+       dynamic_struct_visitor = side_ptr_get(item->u.side_dynamic.side_dynamic_struct_visitor);
+       if (!dynamic_struct_visitor)
+               abort();
+       app_ctx = side_ptr_get(dynamic_struct_visitor->app_ctx);
+       status = side_ptr_get(dynamic_struct_visitor->visitor)(&tracer_ctx, app_ctx);
+       switch (status) {
+       case SIDE_VISITOR_STATUS_OK:
+               break;
+       case SIDE_VISITOR_STATUS_ERROR:
+               fprintf(stderr, "ERROR: Visitor error\n");
+               abort();
+       }
+       if (type_visitor->dynamic_struct_visitor_func)
+               type_visitor->dynamic_struct_visitor_func(SIDE_TYPE_VISITOR_AFTER, item, priv);
+}
+
+static
+void type_visitor_dynamic_vla(const struct side_type_visitor *type_visitor, const struct side_arg_dynamic_vla *vla, void *priv)
+{
+       const struct side_arg *sav = side_ptr_get(vla->sav);
+       uint32_t i, side_sav_len = vla->len;
+
+       if (type_visitor->dynamic_vla_func)
+               type_visitor->dynamic_vla_func(SIDE_TYPE_VISITOR_BEFORE, vla, priv);
+       for (i = 0; i < side_sav_len; i++)
+               visit_dynamic_elem(type_visitor, &sav[i], priv);
+       if (type_visitor->dynamic_vla_func)
+               type_visitor->dynamic_vla_func(SIDE_TYPE_VISITOR_AFTER, vla, priv);
+}
+
+struct tracer_dynamic_vla_visitor_priv {
+       const struct side_type_visitor *type_visitor;
+       void *priv;
+       int i;
+};
+
+static
+enum side_visitor_status tracer_dynamic_vla_write_elem_cb(
+                       const struct side_tracer_visitor_ctx *tracer_ctx,
+                       const struct side_arg *elem)
+{
+       struct tracer_dynamic_vla_visitor_priv *tracer_priv =
+               (struct tracer_dynamic_vla_visitor_priv *) tracer_ctx->priv;
+
+       visit_dynamic_elem(tracer_priv->type_visitor, elem, tracer_priv->priv);
+       return SIDE_VISITOR_STATUS_OK;
+}
+
+static
+void type_visitor_dynamic_vla_visitor(const struct side_type_visitor *type_visitor, const struct side_arg *item, void *priv)
+{
+       struct side_arg_dynamic_vla_visitor *dynamic_vla_visitor;
+       struct tracer_dynamic_vla_visitor_priv tracer_priv = {
+               .type_visitor = type_visitor,
+               .priv = priv,
+               .i = 0,
+       };
+       const struct side_tracer_visitor_ctx tracer_ctx = {
+               .write_elem = tracer_dynamic_vla_write_elem_cb,
+               .priv = &tracer_priv,
+       };
+       enum side_visitor_status status;
+       void *app_ctx;
+
+       if (type_visitor->dynamic_vla_visitor_func)
+               type_visitor->dynamic_vla_visitor_func(SIDE_TYPE_VISITOR_BEFORE, item, priv);
+       dynamic_vla_visitor = side_ptr_get(item->u.side_dynamic.side_dynamic_vla_visitor);
+       if (!dynamic_vla_visitor)
+               abort();
+       app_ctx = side_ptr_get(dynamic_vla_visitor->app_ctx);
+       status = side_ptr_get(dynamic_vla_visitor->visitor)(&tracer_ctx, app_ctx);
+       switch (status) {
+       case SIDE_VISITOR_STATUS_OK:
+               break;
+       case SIDE_VISITOR_STATUS_ERROR:
+               fprintf(stderr, "ERROR: Visitor error\n");
+               abort();
+       }
+       if (type_visitor->dynamic_vla_visitor_func)
+               type_visitor->dynamic_vla_visitor_func(SIDE_TYPE_VISITOR_AFTER, item, priv);
+}
+
+static
+void visit_dynamic_type(const struct side_type_visitor *type_visitor, const struct side_arg *dynamic_item, void *priv)
+{
+       switch (side_enum_get(dynamic_item->type)) {
+       /* Dynamic basic types */
+       case SIDE_TYPE_DYNAMIC_NULL:
+               if (type_visitor->dynamic_null_func)
+                       type_visitor->dynamic_null_func(dynamic_item, priv);
+               break;
+       case SIDE_TYPE_DYNAMIC_BOOL:
+               if (type_visitor->dynamic_bool_func)
+                       type_visitor->dynamic_bool_func(dynamic_item, priv);
+               break;
+       case SIDE_TYPE_DYNAMIC_INTEGER:
+               if (type_visitor->dynamic_integer_func)
+                       type_visitor->dynamic_integer_func(dynamic_item, priv);
+               break;
+       case SIDE_TYPE_DYNAMIC_BYTE:
+               if (type_visitor->dynamic_byte_func)
+                       type_visitor->dynamic_byte_func(dynamic_item, priv);
+               break;
+       case SIDE_TYPE_DYNAMIC_POINTER:
+               if (type_visitor->dynamic_pointer_func)
+                       type_visitor->dynamic_pointer_func(dynamic_item, priv);
+               break;
+       case SIDE_TYPE_DYNAMIC_FLOAT:
+               if (type_visitor->dynamic_float_func)
+                       type_visitor->dynamic_float_func(dynamic_item, priv);
+               break;
+       case SIDE_TYPE_DYNAMIC_STRING:
+               if (type_visitor->dynamic_string_func)
+                       type_visitor->dynamic_string_func(dynamic_item, priv);
+               break;
+
+       /* Dynamic compound types */
+       case SIDE_TYPE_DYNAMIC_STRUCT:
+               type_visitor_dynamic_struct(type_visitor, side_ptr_get(dynamic_item->u.side_dynamic.side_dynamic_struct), priv);
+               break;
+       case SIDE_TYPE_DYNAMIC_STRUCT_VISITOR:
+               type_visitor_dynamic_struct_visitor(type_visitor, dynamic_item, priv);
+               break;
+       case SIDE_TYPE_DYNAMIC_VLA:
+               type_visitor_dynamic_vla(type_visitor, side_ptr_get(dynamic_item->u.side_dynamic.side_dynamic_vla), priv);
+               break;
+       case SIDE_TYPE_DYNAMIC_VLA_VISITOR:
+               type_visitor_dynamic_vla_visitor(type_visitor, dynamic_item, priv);
+               break;
+       default:
+               fprintf(stderr, "<UNKNOWN TYPE>\n");
+               abort();
+       }
+}
+
+static
+void visit_dynamic_elem(const struct side_type_visitor *type_visitor, const struct side_arg *dynamic_item, void *priv)
+{
+       if (type_visitor->elem_func)
+               type_visitor->dynamic_elem_func(SIDE_TYPE_VISITOR_BEFORE, dynamic_item, priv);
+       visit_dynamic_type(type_visitor, dynamic_item, priv);
+       if (type_visitor->elem_func)
+               type_visitor->dynamic_elem_func(SIDE_TYPE_VISITOR_AFTER, dynamic_item, priv);
+}
+
+void side_visit_type(const struct side_type_visitor *type_visitor, const struct side_type *type_desc, const struct side_arg *item, void *priv)
+{
+       enum side_type_label type;
+
+       switch (side_enum_get(type_desc->type)) {
+       case SIDE_TYPE_ENUM:
+               switch (side_enum_get(item->type)) {
+               case SIDE_TYPE_U8:
+               case SIDE_TYPE_U16:
+               case SIDE_TYPE_U32:
+               case SIDE_TYPE_U64:
+               case SIDE_TYPE_U128:
+               case SIDE_TYPE_S8:
+               case SIDE_TYPE_S16:
+               case SIDE_TYPE_S32:
+               case SIDE_TYPE_S64:
+               case SIDE_TYPE_S128:
+                       break;
+               default:
+                       fprintf(stderr, "ERROR: type mismatch between description and arguments\n");
+                       abort();
+                       break;
+               }
+               break;
+
+       case SIDE_TYPE_ENUM_BITMAP:
+               switch (side_enum_get(item->type)) {
+               case SIDE_TYPE_U8:
+               case SIDE_TYPE_BYTE:
+               case SIDE_TYPE_U16:
+               case SIDE_TYPE_U32:
+               case SIDE_TYPE_U64:
+               case SIDE_TYPE_U128:
+               case SIDE_TYPE_ARRAY:
+               case SIDE_TYPE_VLA:
+                       break;
+               default:
+                       fprintf(stderr, "ERROR: type mismatch between description and arguments\n");
+                       abort();
+                       break;
+               }
+               break;
+
+       case SIDE_TYPE_GATHER_ENUM:
+               switch (side_enum_get(item->type)) {
+               case SIDE_TYPE_GATHER_INTEGER:
+                       break;
+               default:
+                       fprintf(stderr, "ERROR: type mismatch between description and arguments\n");
+                       abort();
+                       break;
+               }
+               break;
+
+       case SIDE_TYPE_DYNAMIC:
+               switch (side_enum_get(item->type)) {
+               case SIDE_TYPE_DYNAMIC_NULL:
+               case SIDE_TYPE_DYNAMIC_BOOL:
+               case SIDE_TYPE_DYNAMIC_INTEGER:
+               case SIDE_TYPE_DYNAMIC_BYTE:
+               case SIDE_TYPE_DYNAMIC_POINTER:
+               case SIDE_TYPE_DYNAMIC_FLOAT:
+               case SIDE_TYPE_DYNAMIC_STRING:
+               case SIDE_TYPE_DYNAMIC_STRUCT:
+               case SIDE_TYPE_DYNAMIC_STRUCT_VISITOR:
+               case SIDE_TYPE_DYNAMIC_VLA:
+               case SIDE_TYPE_DYNAMIC_VLA_VISITOR:
+                       break;
+               default:
+                       fprintf(stderr, "ERROR: Unexpected dynamic type\n");
+                       abort();
+                       break;
+               }
+               break;
+
+       default:
+               if (side_enum_get(type_desc->type) != side_enum_get(item->type)) {
+                       fprintf(stderr, "ERROR: type mismatch between description and arguments\n");
+                       abort();
+               }
+               break;
+       }
+
+       if (side_enum_get(type_desc->type) == SIDE_TYPE_ENUM || side_enum_get(type_desc->type) == SIDE_TYPE_ENUM_BITMAP || side_enum_get(type_desc->type) == SIDE_TYPE_GATHER_ENUM)
+               type = side_enum_get(type_desc->type);
+       else
+               type = side_enum_get(item->type);
+
+       switch (type) {
+               /* Stack-copy basic types */
+       case SIDE_TYPE_NULL:
+               if (type_visitor->null_type_func)
+                       type_visitor->null_type_func(type_desc, item, priv);
+               break;
+       case SIDE_TYPE_BOOL:
+               if (type_visitor->bool_type_func)
+                       type_visitor->bool_type_func(type_desc, item, priv);
+               break;
+       case SIDE_TYPE_U8:              /* Fallthrough */
+       case SIDE_TYPE_U16:             /* Fallthrough */
+       case SIDE_TYPE_U32:             /* Fallthrough */
+       case SIDE_TYPE_U64:             /* Fallthrough */
+       case SIDE_TYPE_U128:            /* Fallthrough */
+       case SIDE_TYPE_S8:              /* Fallthrough */
+       case SIDE_TYPE_S16:             /* Fallthrough */
+       case SIDE_TYPE_S32:             /* Fallthrough */
+       case SIDE_TYPE_S64:             /* Fallthrough */
+       case SIDE_TYPE_S128:
+               if (type_visitor->integer_type_func)
+                       type_visitor->integer_type_func(type_desc, item, priv);
+               break;
+       case SIDE_TYPE_BYTE:
+               if (type_visitor->byte_type_func)
+                       type_visitor->byte_type_func(type_desc, item, priv);
+               break;
+       case SIDE_TYPE_POINTER:
+               if (type_visitor->pointer_type_func)
+                       type_visitor->pointer_type_func(type_desc, item, priv);
+               break;
+       case SIDE_TYPE_FLOAT_BINARY16:  /* Fallthrough */
+       case SIDE_TYPE_FLOAT_BINARY32:  /* Fallthrough */
+       case SIDE_TYPE_FLOAT_BINARY64:  /* Fallthrough */
+       case SIDE_TYPE_FLOAT_BINARY128:
+               if (type_visitor->float_type_func)
+                       type_visitor->float_type_func(type_desc, item, priv);
+               break;
+       case SIDE_TYPE_STRING_UTF8:     /* Fallthrough */
+       case SIDE_TYPE_STRING_UTF16:    /* Fallthrough */
+       case SIDE_TYPE_STRING_UTF32:
+               if (type_visitor->string_type_func)
+                       type_visitor->string_type_func(type_desc, item, priv);
+               break;
+       case SIDE_TYPE_ENUM:
+               if (type_visitor->enum_type_func)
+                       type_visitor->enum_type_func(type_desc, item, priv);
+               break;
+       case SIDE_TYPE_ENUM_BITMAP:
+               if (type_visitor->enum_bitmap_type_func)
+                       type_visitor->enum_bitmap_type_func(type_desc, item, priv);
+               break;
+
+               /* Stack-copy compound types */
+       case SIDE_TYPE_STRUCT:
+               type_visitor_struct(type_visitor, type_desc, side_ptr_get(item->u.side_static.side_struct), priv);
+               break;
+       case SIDE_TYPE_VARIANT:
+               type_visitor_variant(type_visitor, type_desc, side_ptr_get(item->u.side_static.side_variant), priv);
+               break;
+       case SIDE_TYPE_ARRAY:
+               type_visitor_array(type_visitor, type_desc, side_ptr_get(item->u.side_static.side_array), priv);
+               break;
+       case SIDE_TYPE_VLA:
+               type_visitor_vla(type_visitor, type_desc, side_ptr_get(item->u.side_static.side_vla), priv);
+               break;
+       case SIDE_TYPE_VLA_VISITOR:
+               type_visitor_vla_visitor(type_visitor, type_desc, side_ptr_get(item->u.side_static.side_vla_visitor), priv);
+               break;
+
+               /* Gather basic types */
+       case SIDE_TYPE_GATHER_BOOL:
+               (void) type_visitor_gather_bool(type_visitor, &type_desc->u.side_gather, side_ptr_get(item->u.side_static.side_bool_gather_ptr), priv);
+               break;
+       case SIDE_TYPE_GATHER_INTEGER:
+               (void) type_visitor_gather_integer(type_visitor, &type_desc->u.side_gather, side_ptr_get(item->u.side_static.side_integer_gather_ptr), SIDE_TYPE_GATHER_INTEGER, priv);
+               break;
+       case SIDE_TYPE_GATHER_BYTE:
+               (void) type_visitor_gather_byte(type_visitor, &type_desc->u.side_gather, side_ptr_get(item->u.side_static.side_byte_gather_ptr), priv);
+               break;
+       case SIDE_TYPE_GATHER_POINTER:
+               (void) type_visitor_gather_integer(type_visitor, &type_desc->u.side_gather, side_ptr_get(item->u.side_static.side_integer_gather_ptr), SIDE_TYPE_GATHER_POINTER, priv);
+               break;
+       case SIDE_TYPE_GATHER_FLOAT:
+               (void) type_visitor_gather_float(type_visitor, &type_desc->u.side_gather, side_ptr_get(item->u.side_static.side_float_gather_ptr), priv);
+               break;
+       case SIDE_TYPE_GATHER_STRING:
+               (void) type_visitor_gather_string(type_visitor, &type_desc->u.side_gather, side_ptr_get(item->u.side_static.side_string_gather_ptr), priv);
+               break;
+
+               /* Gather compound type */
+       case SIDE_TYPE_GATHER_STRUCT:
+               (void) type_visitor_gather_struct(type_visitor, &type_desc->u.side_gather, side_ptr_get(item->u.side_static.side_struct_gather_ptr), priv);
+               break;
+       case SIDE_TYPE_GATHER_ARRAY:
+               (void) type_visitor_gather_array(type_visitor, &type_desc->u.side_gather, side_ptr_get(item->u.side_static.side_array_gather_ptr), priv);
+               break;
+       case SIDE_TYPE_GATHER_VLA:
+               (void) type_visitor_gather_vla(type_visitor, &type_desc->u.side_gather, side_ptr_get(item->u.side_static.side_array_gather_ptr),
+                               side_ptr_get(item->u.side_static.side_vla_gather.length_ptr), priv);
+               break;
+
+               /* Gather enumeration types */
+       case SIDE_TYPE_GATHER_ENUM:
+               (void) type_visitor_gather_enum(type_visitor, &type_desc->u.side_gather, side_ptr_get(item->u.side_static.side_integer_gather_ptr), priv);
+               break;
+
+       /* Dynamic basic types */
+       case SIDE_TYPE_DYNAMIC_NULL:            /* Fallthrough */
+       case SIDE_TYPE_DYNAMIC_BOOL:            /* Fallthrough */
+       case SIDE_TYPE_DYNAMIC_INTEGER:         /* Fallthrough */
+       case SIDE_TYPE_DYNAMIC_BYTE:            /* Fallthrough */
+       case SIDE_TYPE_DYNAMIC_POINTER:         /* Fallthrough */
+       case SIDE_TYPE_DYNAMIC_FLOAT:           /* Fallthrough */
+       case SIDE_TYPE_DYNAMIC_STRING:          /* Fallthrough */
+
+       /* Dynamic compound types */
+       case SIDE_TYPE_DYNAMIC_STRUCT:          /* Fallthrough */
+       case SIDE_TYPE_DYNAMIC_STRUCT_VISITOR:  /* Fallthrough */
+       case SIDE_TYPE_DYNAMIC_VLA:             /* Fallthrough */
+       case SIDE_TYPE_DYNAMIC_VLA_VISITOR:
+               visit_dynamic_type(type_visitor, item, priv);
+               break;
+
+       default:
+               fprintf(stderr, "<UNKNOWN TYPE>\n");
+               abort();
+       }
+}
+
+void type_visitor_event(const struct side_type_visitor *type_visitor,
+               const struct side_event_description *desc,
+               const struct side_arg_vec *side_arg_vec,
+               const struct side_arg_dynamic_struct *var_struct,
+               void *caller_addr, void *priv)
+{
+       const struct side_arg *sav = side_ptr_get(side_arg_vec->sav);
+       uint32_t i, side_sav_len = side_arg_vec->len;
+
+       if (desc->nr_fields != side_sav_len) {
+               fprintf(stderr, "ERROR: number of fields mismatch between description and arguments\n");
+               abort();
+       }
+       if (type_visitor->event_func)
+               type_visitor->event_func(SIDE_TYPE_VISITOR_BEFORE, desc, side_arg_vec, var_struct, caller_addr, priv);
+       if (side_sav_len) {
+               if (type_visitor->static_fields_func)
+                       type_visitor->static_fields_func(SIDE_TYPE_VISITOR_BEFORE, side_arg_vec, priv);
+               for (i = 0; i < side_sav_len; i++)
+                       side_visit_field(type_visitor, &side_ptr_get(desc->fields)[i], &sav[i], priv);
+               if (type_visitor->static_fields_func)
+                       type_visitor->static_fields_func(SIDE_TYPE_VISITOR_AFTER, side_arg_vec, priv);
+       }
+       if (var_struct) {
+               uint32_t var_struct_len = var_struct->len;
+
+               if (type_visitor->variadic_fields_func)
+                       type_visitor->variadic_fields_func(SIDE_TYPE_VISITOR_BEFORE, var_struct, priv);
+               for (i = 0; i < var_struct_len; i++)
+                       visit_dynamic_field(type_visitor, &side_ptr_get(var_struct->fields)[i], priv);
+               if (type_visitor->variadic_fields_func)
+                       type_visitor->variadic_fields_func(SIDE_TYPE_VISITOR_AFTER, var_struct, priv);
+       }
+       if (type_visitor->event_func)
+               type_visitor->event_func(SIDE_TYPE_VISITOR_AFTER, desc, side_arg_vec, var_struct, caller_addr, priv);
+}
diff --git a/src/visit-arg-vec.h b/src/visit-arg-vec.h
new file mode 100644 (file)
index 0000000..ab48ec7
--- /dev/null
@@ -0,0 +1,96 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright 2024 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ */
+
+#ifndef _VISIT_ARG_VEC_H
+#define _VISIT_ARG_VEC_H
+
+#include <side/trace.h>
+
+enum side_type_visitor_location {
+       SIDE_TYPE_VISITOR_BEFORE,
+       SIDE_TYPE_VISITOR_AFTER,
+};
+
+struct side_type_visitor {
+       void (*event_func)(enum side_type_visitor_location loc,
+                       const struct side_event_description *desc,
+                       const struct side_arg_vec *side_arg_vec,
+                       const struct side_arg_dynamic_struct *var_struct,
+                       void *caller_addr,
+                       void *priv);
+
+       void (*static_fields_func)(enum side_type_visitor_location loc,
+                       const struct side_arg_vec *side_arg_vec,
+                       void *priv);
+
+       void (*variadic_fields_func)(enum side_type_visitor_location loc,
+                       const struct side_arg_dynamic_struct *var_struct,
+                       void *priv);
+
+       /* Stack-copy basic types. */
+       void (*field_func)(enum side_type_visitor_location loc, const struct side_event_field *item_desc, void *priv);
+       void (*elem_func)(enum side_type_visitor_location loc, const struct side_type *type_desc, void *priv);
+
+       void (*null_type_func)(const struct side_type *type_desc, const struct side_arg *item, void *priv);
+       void (*bool_type_func)(const struct side_type *type_desc, const struct side_arg *item, void *priv);
+       void (*integer_type_func)(const struct side_type *type_desc, const struct side_arg *item, void *priv);
+       void (*byte_type_func)(const struct side_type *type_desc, const struct side_arg *item, void *priv);
+       void (*pointer_type_func)(const struct side_type *type_desc, const struct side_arg *item, void *priv);
+       void (*float_type_func)(const struct side_type *type_desc, const struct side_arg *item, void *priv);
+       void (*string_type_func)(const struct side_type *type_desc, const struct side_arg *item, void *priv);
+
+       /* Stack-copy compound types. */
+       void (*struct_type_func)(enum side_type_visitor_location loc, const struct side_type_struct *side_struct, const struct side_arg_vec *side_arg_vec, void *priv);
+       void (*array_type_func)(enum side_type_visitor_location loc, const struct side_type_array *side_array, const struct side_arg_vec *side_arg_vec, void *priv);
+       void (*vla_type_func)(enum side_type_visitor_location loc, const struct side_type_vla *side_vla, const struct side_arg_vec *side_arg_vec, void *priv);
+       void (*vla_visitor_type_func)(enum side_type_visitor_location loc, const struct side_type_vla_visitor *side_vla_visitor, const struct side_arg_vla_visitor *side_arg_vla_visitor, void *priv);
+
+       /* Stack-copy enumeration types. */
+       void (*enum_type_func)(const struct side_type *type_desc, const struct side_arg *item, void *priv);
+       void (*enum_bitmap_type_func)(const struct side_type *type_desc, const struct side_arg *item, void *priv);
+
+       /* Gather basic types. */
+       void (*gather_bool_type_func)(const struct side_type_gather_bool *type, const union side_bool_value *value, void *priv);
+       void (*gather_byte_type_func)(const struct side_type_gather_byte *type, const uint8_t *_ptr, void *priv);
+       void (*gather_integer_type_func)(const struct side_type_gather_integer *type, const union side_integer_value *value, void *priv);
+       void (*gather_pointer_type_func)(const struct side_type_gather_integer *type, const union side_integer_value *value, void *priv);
+       void (*gather_float_type_func)(const struct side_type_gather_float *type, const union side_float_value *value, void *priv);
+       void (*gather_string_type_func)(const struct side_type_gather_string *type, const void *p, uint8_t unit_size,
+                               enum side_type_label_byte_order byte_order, size_t strlen_with_null, void *priv);
+
+       /* Gather compound types. */
+       void (*gather_struct_type_func)(enum side_type_visitor_location loc, const struct side_type_struct *type, void *priv);
+       void (*gather_array_type_func)(enum side_type_visitor_location loc, const struct side_type_array *type, void *priv);
+       void (*gather_vla_type_func)(enum side_type_visitor_location loc, const struct side_type_vla *type, uint32_t length, void *priv);
+
+       /* Gather enumeration types. */
+       void (*gather_enum_type_func)(const struct side_type_gather_enum *type, const union side_integer_value *value, void *priv);
+
+       /* Dynamic basic types. */
+       void (*dynamic_field_func)(enum side_type_visitor_location loc, const struct side_arg_dynamic_field *field, void *priv);
+       void (*dynamic_elem_func)(enum side_type_visitor_location loc, const struct side_arg *dynamic_item, void *priv);
+
+       void (*dynamic_null_func)(const struct side_arg *item, void *priv);
+       void (*dynamic_bool_func)(const struct side_arg *item, void *priv);
+       void (*dynamic_integer_func)(const struct side_arg *item, void *priv);
+       void (*dynamic_byte_func)(const struct side_arg *item, void *priv);
+       void (*dynamic_pointer_func)(const struct side_arg *item, void *priv);
+       void (*dynamic_float_func)(const struct side_arg *item, void *priv);
+       void (*dynamic_string_func)(const struct side_arg *item, void *priv);
+
+       /* Dynamic compound types. */
+       void (*dynamic_struct_func)(enum side_type_visitor_location loc, const struct side_arg_dynamic_struct *dynamic_struct, void *priv);
+       void (*dynamic_struct_visitor_func)(enum side_type_visitor_location loc, const struct side_arg *item, void *priv);
+       void (*dynamic_vla_func)(enum side_type_visitor_location loc, const struct side_arg_dynamic_vla *vla, void *priv);
+       void (*dynamic_vla_visitor_func)(enum side_type_visitor_location loc, const struct side_arg *item, void *priv);
+};
+
+void type_visitor_event(const struct side_type_visitor *type_visitor,
+               const struct side_event_description *desc,
+               const struct side_arg_vec *side_arg_vec,
+               const struct side_arg_dynamic_struct *var_struct,
+               void *caller_addr, void *priv);
+
+#endif /* _VISIT_ARG_VEC_H */
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