include/side/abi/type-value.h

   1 // SPDX-License-Identifier: MIT
   2 /*
   3  * Copyright 2022-2023 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  */
   5
   6 #ifndef SIDE_ABI_TYPE_VALUE_H
   7 #define SIDE_ABI_TYPE_VALUE_H
   8
   9 #include <stdint.h>
  10 #include <side/macros.h>
  11 #include <side/endian.h>
  12
  13 /*
  14  * SIDE ABI for type values.
  15  *
  16  * The extensibility scheme for the SIDE ABI for type values is as
  17  * follows:
  18  *
  19  * * Existing type values are never changed nor extended. Type values
  20  *   can be added to the ABI by reserving a label within enum
  21  *   side_type_label.
  22  * * Each union part of the ABI has an explicit size defined by a
  23  *   side_padding() member. Each structure and union have a static
  24  *   assert validating its size.
  25  * * Changing the semantic of the existing type value fields is a
  26  *   breaking ABI change.
  27  *
  28  * Handling of unknown type values by the tracers:
  29  *
  30  * * A tracer may choose to support only a subset of the type values
  31  *   supported by libside. When encountering an unknown or unsupported
  32  *   type value, the tracer has the option to either disallow the entire
  33  *   event or skip over the unknown type, both at event registration and
  34  *   when receiving the side_call arguments.
  35  */
  36
  37 enum side_type_label_byte_order {
  38         SIDE_TYPE_BYTE_ORDER_LE = 0,
  39         SIDE_TYPE_BYTE_ORDER_BE = 1,
  40 };
  41
  42 union side_integer_value {
  43         uint8_t side_u8;
  44         uint16_t side_u16;
  45         uint32_t side_u32;
  46         uint64_t side_u64;
  47         int8_t side_s8;
  48         int16_t side_s16;
  49         int32_t side_s32;
  50         int64_t side_s64;
  51         uintptr_t side_uptr;
  52         side_padding(32);
  53 } SIDE_PACKED;
  54 side_check_size(union side_integer_value, 32);
  55
  56 union side_bool_value {
  57         uint8_t side_bool8;
  58         uint16_t side_bool16;
  59         uint32_t side_bool32;
  60         uint64_t side_bool64;
  61         side_padding(32);
  62 } SIDE_PACKED;
  63 side_check_size(union side_bool_value, 32);
  64
  65 union side_float_value {
  66 #if __HAVE_FLOAT16
  67         _Float16 side_float_binary16;
  68 #endif
  69 #if __HAVE_FLOAT32
  70         _Float32 side_float_binary32;
  71 #endif
  72 #if __HAVE_FLOAT64
  73         _Float64 side_float_binary64;
  74 #endif
  75 #if __HAVE_FLOAT128
  76         _Float128 side_float_binary128;
  77 #endif
  78         side_padding(32);
  79 } SIDE_PACKED;
  80 side_check_size(union side_float_value, 32);
  81
  82 struct side_type_raw_string {
  83         side_ptr_t(const void) p;       /* pointer to string */
  84         uint8_t unit_size;              /* 1, 2, or 4 bytes */
  85         side_enum_t(enum side_type_label_byte_order, uint8_t) byte_order;
  86 } SIDE_PACKED;
  87 side_check_size(struct side_type_raw_string, 18);
  88
  89 #endif /* SIDE_ABI_TYPE_VALUE_H */