#include "inferior.h"
#include "ax.h"
#include "ax-gdb.h"
+#include "regcache.h"
+#include "objfiles.h"
#include "elf/dwarf2.h"
#include "dwarf2expr.h"
#define DWARF2_REG_TO_REGNUM(REG) (REG)
#endif
+/* A helper function for dealing with location lists. Given a
+ symbol baton (BATON) and a pc value (PC), find the appropriate
+ location expression, set *LOCEXPR_LENGTH, and return a pointer
+ to the beginning of the expression. Returns NULL on failure.
+
+ For now, only return the first matching location expression; there
+ can be more than one in the list. */
+
+static char *
+find_location_expression (struct dwarf2_loclist_baton *baton,
+ size_t *locexpr_length, CORE_ADDR pc)
+{
+ CORE_ADDR base_address = baton->base_address;
+ CORE_ADDR low, high;
+ char *loc_ptr, *buf_end;
+ unsigned int addr_size = TARGET_ADDR_BIT / TARGET_CHAR_BIT, length;
+ CORE_ADDR base_mask = ~(~(CORE_ADDR)1 << (addr_size * 8 - 1));
+
+ loc_ptr = baton->data;
+ buf_end = baton->data + baton->size;
+
+ while (1)
+ {
+ low = dwarf2_read_address (loc_ptr, buf_end, &length);
+ loc_ptr += length;
+ high = dwarf2_read_address (loc_ptr, buf_end, &length);
+ loc_ptr += length;
+
+ /* An end-of-list entry. */
+ if (low == 0 && high == 0)
+ return NULL;
+
+ /* A base-address-selection entry. */
+ if ((low & base_mask) == base_mask)
+ {
+ base_address = high;
+ continue;
+ }
+
+ /* Otherwise, a location expression entry. */
+ low += base_address;
+ high += base_address;
+
+ length = extract_unsigned_integer (loc_ptr, 2);
+ loc_ptr += 2;
+
+ if (pc >= low && pc < high)
+ {
+ *locexpr_length = length;
+ return loc_ptr;
+ }
+
+ loc_ptr += length;
+ }
+}
+
/* This is the baton used when performing dwarf2 expression
evaluation. */
struct dwarf_expr_baton
type will be returned in LVALP, and for lval_memory the register
save address will be returned in ADDRP. */
static CORE_ADDR
-dwarf_expr_read_reg (void *baton, int regnum, enum lval_type *lvalp,
- CORE_ADDR *addrp)
+dwarf_expr_read_reg (void *baton, int dwarf_regnum)
{
- CORE_ADDR result;
struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton;
- char *buf = (char *) alloca (MAX_REGISTER_RAW_SIZE);
- int optimized, realnum;
+ CORE_ADDR result, save_addr;
+ enum lval_type lval_type;
+ char *buf;
+ int optimized, regnum, realnum, regsize;
+
+ regnum = DWARF2_REG_TO_REGNUM (dwarf_regnum);
+ regsize = register_size (current_gdbarch, regnum);
+ buf = (char *) alloca (regsize);
- frame_register (debaton->frame, DWARF2_REG_TO_REGNUM (regnum),
- &optimized, lvalp, addrp, &realnum, buf);
- result = extract_address (buf, REGISTER_RAW_SIZE (regnum));
+ frame_register (debaton->frame, regnum, &optimized, &lval_type, &save_addr,
+ &realnum, buf);
+ /* NOTE: cagney/2003-05-22: This extract is assuming that a DWARF 2
+ address is always unsigned. That may or may not be true. */
+ result = extract_unsigned_integer (buf, regsize);
return result;
}
static void
dwarf_expr_frame_base (void *baton, unsigned char **start, size_t * length)
{
+ /* FIXME: cagney/2003-03-26: This code should be using
+ get_frame_base_address(), and then implement a dwarf2 specific
+ this_base method. */
struct symbol *framefunc;
- struct dwarf2_locexpr_baton *symbaton;
struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton;
+
framefunc = get_frame_function (debaton->frame);
- symbaton = SYMBOL_LOCATION_BATON (framefunc);
- *start = symbaton->data;
- *length = symbaton->size;
+
+ if (SYMBOL_LOCATION_FUNCS (framefunc) == &dwarf2_loclist_funcs)
+ {
+ struct dwarf2_loclist_baton *symbaton;
+ symbaton = SYMBOL_LOCATION_BATON (framefunc);
+ *start = find_location_expression (symbaton, length,
+ get_frame_pc (debaton->frame));
+ }
+ else
+ {
+ struct dwarf2_locexpr_baton *symbaton;
+ symbaton = SYMBOL_LOCATION_BATON (framefunc);
+ *length = symbaton->size;
+ *start = symbaton->data;
+ }
+
+ if (*start == NULL)
+ error ("Could not find the frame base for \"%s\".",
+ SYMBOL_NATURAL_NAME (framefunc));
}
/* Using the objfile specified in BATON, find the address for the
addr = target_get_thread_local_address (inferior_ptid,
debaton->objfile,
offset);
+ /* It wouldn't be wrong here to try a gdbarch method, too; finding
+ TLS is an ABI-specific thing. But we don't do that yet. */
else
error ("Cannot find thread-local variables on this target");
struct dwarf_expr_baton baton;
struct dwarf_expr_context *ctx;
+ if (size == 0)
+ {
+ retval = allocate_value (SYMBOL_TYPE (var));
+ VALUE_LVAL (retval) = not_lval;
+ VALUE_OPTIMIZED_OUT (retval) = 1;
+ }
+
baton.frame = frame;
baton.objfile = objfile;
ctx->get_tls_address = dwarf_expr_tls_address;
dwarf_expr_eval (ctx, data, size);
-
- retval = allocate_value (SYMBOL_TYPE (var));
- VALUE_BFD_SECTION (retval) = SYMBOL_BFD_SECTION (var);
+ result = dwarf_expr_fetch (ctx, 0);
if (ctx->in_reg)
{
- store_unsigned_integer (VALUE_CONTENTS_RAW (retval),
- TYPE_LENGTH (SYMBOL_TYPE (var)),
- dwarf_expr_fetch (ctx, 0));
- VALUE_LVAL (retval) = lval_register;
- VALUE_REGNO (retval) = ctx->regnum;
+ int regnum = DWARF2_REG_TO_REGNUM (result);
+ retval = value_from_register (SYMBOL_TYPE (var), regnum, frame);
}
else
{
- result = dwarf_expr_fetch (ctx, 0);
+ retval = allocate_value (SYMBOL_TYPE (var));
+ VALUE_BFD_SECTION (retval) = SYMBOL_BFD_SECTION (var);
+
VALUE_LVAL (retval) = lval_memory;
VALUE_LAZY (retval) = 1;
VALUE_ADDRESS (retval) = result;
/* Reads from registers do require a frame. */
static CORE_ADDR
-needs_frame_read_reg (void *baton, int regnum, enum lval_type *lvalp,
- CORE_ADDR *addrp)
+needs_frame_read_reg (void *baton, int regnum)
{
struct needs_frame_baton *nf_baton = baton;
nf_baton->needs_frame = 1;
return baton.needs_frame;
}
+static void
+dwarf2_tracepoint_var_ref (struct symbol * symbol, struct agent_expr * ax,
+ struct axs_value * value, unsigned char *data,
+ int size)
+{
+ if (size == 0)
+ error ("Symbol \"%s\" has been optimized out.",
+ SYMBOL_PRINT_NAME (symbol));
+ if (size == 1
+ && data[0] >= DW_OP_reg0
+ && data[0] <= DW_OP_reg31)
+ {
+ value->kind = axs_lvalue_register;
+ value->u.reg = data[0] - DW_OP_reg0;
+ }
+ else if (data[0] == DW_OP_regx)
+ {
+ ULONGEST reg;
+ read_uleb128 (data + 1, data + size, ®);
+ value->kind = axs_lvalue_register;
+ value->u.reg = reg;
+ }
+ else if (data[0] == DW_OP_fbreg)
+ {
+ /* And this is worse than just minimal; we should honor the frame base
+ as above. */
+ int frame_reg;
+ LONGEST frame_offset;
+ unsigned char *buf_end;
+ buf_end = read_sleb128 (data + 1, data + size, &frame_offset);
+ if (buf_end != data + size)
+ error ("Unexpected opcode after DW_OP_fbreg for symbol \"%s\".",
+ SYMBOL_PRINT_NAME (symbol));
+
+ TARGET_VIRTUAL_FRAME_POINTER (ax->scope, &frame_reg, &frame_offset);
+ ax_reg (ax, frame_reg);
+ ax_const_l (ax, frame_offset);
+ ax_simple (ax, aop_add);
+
+ ax_const_l (ax, frame_offset);
+ ax_simple (ax, aop_add);
+ value->kind = axs_lvalue_memory;
+ }
+ else
+ error ("Unsupported DWARF opcode in the location of \"%s\".",
+ SYMBOL_PRINT_NAME (symbol));
+}
\f
/* Return the value of SYMBOL in FRAME using the DWARF-2 expression
evaluator to calculate the location. */
return 1;
}
+ /* The location expression for a TLS variable looks like this (on a
+ 64-bit LE machine):
+
+ DW_AT_location : 10 byte block: 3 4 0 0 0 0 0 0 0 e0
+ (DW_OP_addr: 4; DW_OP_GNU_push_tls_address)
+
+ 0x3 is the encoding for DW_OP_addr, which has an operand as long
+ as the size of an address on the target machine (here is 8
+ bytes). 0xe0 is the encoding for DW_OP_GNU_push_tls_address.
+ The operand represents the offset at which the variable is within
+ the thread local storage. */
+
+ if (dlbaton->size > 1
+ && dlbaton->data[dlbaton->size - 1] == DW_OP_GNU_push_tls_address)
+ if (dlbaton->data[0] == DW_OP_addr)
+ {
+ int bytes_read;
+ CORE_ADDR offset = dwarf2_read_address (&dlbaton->data[1],
+ &dlbaton->data[dlbaton->size - 1],
+ &bytes_read);
+ fprintf_filtered (stream,
+ "a thread-local variable at offset %s in the "
+ "thread-local storage for `%s'",
+ paddr_nz (offset), dlbaton->objfile->name);
+ return 1;
+ }
+
+
fprintf_filtered (stream,
"a variable with complex or multiple locations (DWARF2)");
return 1;
publicly available stub with tracepoint support for me to test
against. When there is one this function should be revisited. */
-void
+static void
locexpr_tracepoint_var_ref (struct symbol * symbol, struct agent_expr * ax,
struct axs_value * value)
{
struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
- if (dlbaton->size == 0)
- error ("Symbol \"%s\" has been optimized out.",
- SYMBOL_PRINT_NAME (symbol));
-
- if (dlbaton->size == 1
- && dlbaton->data[0] >= DW_OP_reg0
- && dlbaton->data[0] <= DW_OP_reg31)
- {
- value->kind = axs_lvalue_register;
- value->u.reg = dlbaton->data[0] - DW_OP_reg0;
- }
- else if (dlbaton->data[0] == DW_OP_regx)
- {
- ULONGEST reg;
- read_uleb128 (dlbaton->data + 1, dlbaton->data + dlbaton->size,
- ®);
- value->kind = axs_lvalue_register;
- value->u.reg = reg;
- }
- else if (dlbaton->data[0] == DW_OP_fbreg)
- {
- /* And this is worse than just minimal; we should honor the frame base
- as above. */
- int frame_reg;
- LONGEST frame_offset;
- unsigned char *buf_end;
-
- buf_end = read_sleb128 (dlbaton->data + 1, dlbaton->data + dlbaton->size,
- &frame_offset);
- if (buf_end != dlbaton->data + dlbaton->size)
- error ("Unexpected opcode after DW_OP_fbreg for symbol \"%s\".",
- SYMBOL_PRINT_NAME (symbol));
-
- TARGET_VIRTUAL_FRAME_POINTER (ax->scope, &frame_reg, &frame_offset);
- ax_reg (ax, frame_reg);
- ax_const_l (ax, frame_offset);
- ax_simple (ax, aop_add);
-
- ax_const_l (ax, frame_offset);
- ax_simple (ax, aop_add);
- value->kind = axs_lvalue_memory;
- }
- else
- error ("Unsupported DWARF opcode in the location of \"%s\".",
- SYMBOL_PRINT_NAME (symbol));
+ dwarf2_tracepoint_var_ref (symbol, ax, value, dlbaton->data, dlbaton->size);
}
/* The set of location functions used with the DWARF-2 expression
locexpr_describe_location,
locexpr_tracepoint_var_ref
};
+
+
+/* Wrapper functions for location lists. These generally find
+ the appropriate location expression and call something above. */
+
+/* Return the value of SYMBOL in FRAME using the DWARF-2 expression
+ evaluator to calculate the location. */
+static struct value *
+loclist_read_variable (struct symbol *symbol, struct frame_info *frame)
+{
+ struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
+ struct value *val;
+ unsigned char *data;
+ size_t size;
+
+ data = find_location_expression (dlbaton, &size,
+ frame ? get_frame_pc (frame) : 0);
+ if (data == NULL)
+ error ("Variable \"%s\" is not available.", SYMBOL_NATURAL_NAME (symbol));
+
+ val = dwarf2_evaluate_loc_desc (symbol, frame, data, size, dlbaton->objfile);
+
+ return val;
+}
+
+/* Return non-zero iff we need a frame to evaluate SYMBOL. */
+static int
+loclist_read_needs_frame (struct symbol *symbol)
+{
+ /* If there's a location list, then assume we need to have a frame
+ to choose the appropriate location expression. With tracking of
+ global variables this is not necessarily true, but such tracking
+ is disabled in GCC at the moment until we figure out how to
+ represent it. */
+
+ return 1;
+}
+
+/* Print a natural-language description of SYMBOL to STREAM. */
+static int
+loclist_describe_location (struct symbol *symbol, struct ui_file *stream)
+{
+ /* FIXME: Could print the entire list of locations. */
+ fprintf_filtered (stream, "a variable with multiple locations");
+ return 1;
+}
+
+/* Describe the location of SYMBOL as an agent value in VALUE, generating
+ any necessary bytecode in AX. */
+static void
+loclist_tracepoint_var_ref (struct symbol * symbol, struct agent_expr * ax,
+ struct axs_value * value)
+{
+ struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
+ unsigned char *data;
+ size_t size;
+
+ data = find_location_expression (dlbaton, &size, ax->scope);
+ if (data == NULL)
+ error ("Variable \"%s\" is not available.", SYMBOL_NATURAL_NAME (symbol));
+
+ dwarf2_tracepoint_var_ref (symbol, ax, value, data, size);
+}
+
+/* The set of location functions used with the DWARF-2 expression
+ evaluator and location lists. */
+struct location_funcs dwarf2_loclist_funcs = {
+ loclist_read_variable,
+ loclist_read_needs_frame,
+ loclist_describe_location,
+ loclist_tracepoint_var_ref
+};
projects / deliverable / binutils-gdb.git / blobdiff