/* Print a natural-language description of SYMBOL to STREAM. */
static int
locexpr_describe_location (struct symbol *symbol, struct ui_file *stream)
{
/* FIXME: be more extensive. */
struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol);
int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
if (dlbaton->size == 1
&& dlbaton->data[0] >= DW_OP_reg0
&& dlbaton->data[0] <= DW_OP_reg31)
{
struct objfile *objfile = dwarf2_per_cu_objfile (dlbaton->per_cu);
struct gdbarch *gdbarch = get_objfile_arch (objfile);
int regno = gdbarch_dwarf2_reg_to_regnum (gdbarch,
dlbaton->data[0] - DW_OP_reg0);
fprintf_filtered (stream,
"a variable in register %s",
gdbarch_register_name (gdbarch, regno));
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)
{
struct objfile *objfile = dwarf2_per_cu_objfile (dlbaton->per_cu);
struct gdbarch *gdbarch = get_objfile_arch (objfile);
CORE_ADDR offset = dwarf2_read_address (gdbarch,
&dlbaton->data[1],
&dlbaton->data[dlbaton->size - 1],
addr_size);
fprintf_filtered (stream,
"a thread-local variable at offset %s in the "
"thread-local storage for `%s'",
paddr_nz (offset), objfile->name);
return 1;
}
fprintf_filtered (stream,
"a variable with complex or multiple locations (DWARF2)");
return 1;
}
/* Using the frame specified in BATON, return the value of register
REGNUM, treated as a pointer. */
static CORE_ADDR
dwarf_expr_read_reg (void *baton, int dwarf_regnum)
{
struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton;
CORE_ADDR result;
int regnum;
regnum = gdbarch_dwarf2_reg_to_regnum (current_gdbarch, dwarf_regnum);
result = address_from_register (builtin_type_void_data_ptr,
regnum, debaton->frame);
return result;
}
/* Using the frame specified in BATON, return the value of register
REGNUM, treated as a pointer. */
static CORE_ADDR
dwarf_expr_read_reg (void *baton, int dwarf_regnum)
{
struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton;
struct gdbarch *gdbarch = get_frame_arch (debaton->frame);
CORE_ADDR result;
int regnum;
regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, dwarf_regnum);
result = address_from_register (builtin_type (gdbarch)->builtin_data_ptr,
regnum, debaton->frame);
return result;
}
/* Evaluate a location description, starting at DATA and with length
SIZE, to find the current location of variable VAR in the context
of FRAME. */
static struct value *
dwarf2_evaluate_loc_desc (struct symbol *var, struct frame_info *frame,
gdb_byte *data, unsigned short size,
struct objfile *objfile)
{
struct gdbarch *arch = get_frame_arch (frame);
struct value *retval;
struct dwarf_expr_baton baton;
struct dwarf_expr_context *ctx;
if (size == 0)
{
retval = allocate_value (SYMBOL_TYPE (var));
VALUE_LVAL (retval) = not_lval;
set_value_optimized_out (retval, 1);
return retval;
}
baton.frame = frame;
baton.objfile = objfile;
ctx = new_dwarf_expr_context ();
ctx->baton = &baton;
ctx->read_reg = dwarf_expr_read_reg;
ctx->read_mem = dwarf_expr_read_mem;
ctx->get_frame_base = dwarf_expr_frame_base;
ctx->get_tls_address = dwarf_expr_tls_address;
dwarf_expr_eval (ctx, data, size);
if (ctx->num_pieces > 0)
{
int i;
long offset = 0;
bfd_byte *contents;
retval = allocate_value (SYMBOL_TYPE (var));
contents = value_contents_raw (retval);
for (i = 0; i < ctx->num_pieces; i++)
{
struct dwarf_expr_piece *p = &ctx->pieces[i];
if (p->in_reg)
{
bfd_byte regval[MAX_REGISTER_SIZE];
int gdb_regnum = gdbarch_dwarf2_reg_to_regnum
(arch, p->value);
get_frame_register (frame, gdb_regnum, regval);
memcpy (contents + offset, regval, p->size);
}
else /* In memory? */
{
read_memory (p->value, contents + offset, p->size);
}
offset += p->size;
}
}
else if (ctx->in_reg)
{
CORE_ADDR dwarf_regnum = dwarf_expr_fetch (ctx, 0);
int gdb_regnum = gdbarch_dwarf2_reg_to_regnum
(arch, dwarf_regnum);
retval = value_from_register (SYMBOL_TYPE (var), gdb_regnum, frame);
}
else
{
CORE_ADDR address = dwarf_expr_fetch (ctx, 0);
retval = allocate_value (SYMBOL_TYPE (var));
VALUE_LVAL (retval) = lval_memory;
set_value_lazy (retval, 1);
VALUE_ADDRESS (retval) = address;
}
set_value_initialized (retval, ctx->initialized);
free_dwarf_expr_context (ctx);
return retval;
}
