/* DWARF 2 location expression support for GDB.
- Copyright (C) 2003, 2005, 2007, 2008, 2009 Free Software Foundation, Inc.
+ Copyright (C) 2003, 2005, 2007, 2008, 2009, 2010
+ Free Software Foundation, Inc.
Contributed by Daniel Jacobowitz, MontaVista Software, Inc.
#include "dwarf2.h"
#include "dwarf2expr.h"
#include "dwarf2loc.h"
+#include "dwarf2-frame.h"
#include "gdb_string.h"
#include "gdb_assert.h"
+static void
+dwarf_expr_frame_base_1 (struct symbol *framefunc, CORE_ADDR pc,
+ gdb_byte **start, size_t *length);
+
/* 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
something has gone wrong. */
gdb_assert (framefunc != NULL);
+ dwarf_expr_frame_base_1 (framefunc,
+ get_frame_address_in_block (debaton->frame),
+ start, length);
+}
+
+static void
+dwarf_expr_frame_base_1 (struct symbol *framefunc, CORE_ADDR pc,
+ gdb_byte **start, size_t *length)
+{
if (SYMBOL_LOCATION_BATON (framefunc) == NULL)
*start = NULL;
else if (SYMBOL_COMPUTED_OPS (framefunc) == &dwarf2_loclist_funcs)
{
struct dwarf2_loclist_baton *symbaton;
- struct frame_info *frame = debaton->frame;
symbaton = SYMBOL_LOCATION_BATON (framefunc);
- *start = find_location_expression (symbaton, length,
- get_frame_address_in_block (frame));
+ *start = find_location_expression (symbaton, length, pc);
}
else
{
SYMBOL_NATURAL_NAME (framefunc));
}
+/* Helper function for dwarf2_evaluate_loc_desc. Computes the CFA for
+ the frame in BATON. */
+
+static CORE_ADDR
+dwarf_expr_frame_cfa (void *baton)
+{
+ struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton;
+ return dwarf2_frame_cfa (debaton->frame);
+}
+
/* Using the objfile specified in BATON, find the address for the
current thread's thread-local storage with offset OFFSET. */
static CORE_ADDR
return target_translate_tls_address (debaton->objfile, offset);
}
+struct piece_closure
+{
+ /* The number of pieces used to describe this variable. */
+ int n_pieces;
+
+ /* The architecture, used only for DWARF_VALUE_STACK. */
+ struct gdbarch *arch;
+
+ /* The pieces themselves. */
+ struct dwarf_expr_piece *pieces;
+};
+
+/* Allocate a closure for a value formed from separately-described
+ PIECES. */
+
+static struct piece_closure *
+allocate_piece_closure (int n_pieces, struct dwarf_expr_piece *pieces,
+ struct gdbarch *arch)
+{
+ struct piece_closure *c = XZALLOC (struct piece_closure);
+
+ c->n_pieces = n_pieces;
+ c->arch = arch;
+ c->pieces = XCALLOC (n_pieces, struct dwarf_expr_piece);
+
+ memcpy (c->pieces, pieces, n_pieces * sizeof (struct dwarf_expr_piece));
+
+ return c;
+}
+
+static void
+read_pieced_value (struct value *v)
+{
+ int i;
+ long offset = 0;
+ gdb_byte *contents;
+ struct piece_closure *c = (struct piece_closure *) value_computed_closure (v);
+ struct frame_info *frame = frame_find_by_id (VALUE_FRAME_ID (v));
+
+ contents = value_contents_raw (v);
+ for (i = 0; i < c->n_pieces; i++)
+ {
+ struct dwarf_expr_piece *p = &c->pieces[i];
+ switch (p->location)
+ {
+ case DWARF_VALUE_REGISTER:
+ {
+ struct gdbarch *arch = get_frame_arch (frame);
+ int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch,
+ p->v.expr.value);
+ int reg_offset = 0;
+
+ if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG
+ && p->size < register_size (arch, gdb_regnum))
+ /* Big-endian, and we want less than full size. */
+ reg_offset = register_size (arch, gdb_regnum) - p->size;
+
+ get_frame_register_bytes (frame, gdb_regnum, reg_offset, p->size,
+ contents + offset);
+ }
+ break;
+
+ case DWARF_VALUE_MEMORY:
+ if (p->v.expr.in_stack_memory)
+ read_stack (p->v.expr.value, contents + offset, p->size);
+ else
+ read_memory (p->v.expr.value, contents + offset, p->size);
+ break;
+
+ case DWARF_VALUE_STACK:
+ {
+ size_t n;
+ int addr_size = gdbarch_addr_bit (c->arch) / 8;
+ n = p->size;
+ if (n > addr_size)
+ n = addr_size;
+ store_unsigned_integer (contents + offset, n,
+ gdbarch_byte_order (c->arch),
+ p->v.expr.value);
+ }
+ break;
+
+ case DWARF_VALUE_LITERAL:
+ {
+ size_t n = p->size;
+ if (n > p->v.literal.length)
+ n = p->v.literal.length;
+ memcpy (contents + offset, p->v.literal.data, n);
+ }
+ break;
+
+ default:
+ internal_error (__FILE__, __LINE__, _("invalid location type"));
+ }
+ offset += p->size;
+ }
+}
+
+static void
+write_pieced_value (struct value *to, struct value *from)
+{
+ int i;
+ long offset = 0;
+ gdb_byte *contents;
+ struct piece_closure *c = (struct piece_closure *) value_computed_closure (to);
+ struct frame_info *frame = frame_find_by_id (VALUE_FRAME_ID (to));
+
+ if (frame == NULL)
+ {
+ set_value_optimized_out (to, 1);
+ return;
+ }
+
+ contents = value_contents_raw (from);
+ for (i = 0; i < c->n_pieces; i++)
+ {
+ struct dwarf_expr_piece *p = &c->pieces[i];
+ switch (p->location)
+ {
+ case DWARF_VALUE_REGISTER:
+ {
+ struct gdbarch *arch = get_frame_arch (frame);
+ int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, p->v.expr.value);
+ int reg_offset = 0;
+
+ if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG
+ && p->size < register_size (arch, gdb_regnum))
+ /* Big-endian, and we want less than full size. */
+ reg_offset = register_size (arch, gdb_regnum) - p->size;
+
+ put_frame_register_bytes (frame, gdb_regnum, reg_offset, p->size,
+ contents + offset);
+ }
+ break;
+ case DWARF_VALUE_MEMORY:
+ write_memory (p->v.expr.value, contents + offset, p->size);
+ break;
+ default:
+ set_value_optimized_out (to, 1);
+ return;
+ }
+ offset += p->size;
+ }
+}
+
+static void *
+copy_pieced_value_closure (struct value *v)
+{
+ struct piece_closure *c = (struct piece_closure *) value_computed_closure (v);
+
+ return allocate_piece_closure (c->n_pieces, c->pieces, c->arch);
+}
+
+static void
+free_pieced_value_closure (struct value *v)
+{
+ struct piece_closure *c = (struct piece_closure *) value_computed_closure (v);
+
+ xfree (c->pieces);
+ xfree (c);
+}
+
+/* Functions for accessing a variable described by DW_OP_piece. */
+static struct lval_funcs pieced_value_funcs = {
+ read_pieced_value,
+ write_pieced_value,
+ copy_pieced_value_closure,
+ free_pieced_value_closure
+};
+
/* Evaluate a location description, starting at DATA and with length
SIZE, to find the current location of variable VAR in the context
of FRAME. */
ctx->read_reg = dwarf_expr_read_reg;
ctx->read_mem = dwarf_expr_read_mem;
ctx->get_frame_base = dwarf_expr_frame_base;
+ ctx->get_frame_cfa = dwarf_expr_frame_cfa;
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)
- {
- struct gdbarch *arch = get_frame_arch (frame);
- 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)
- {
- struct gdbarch *arch = get_frame_arch (frame);
- 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);
+ struct piece_closure *c;
+ struct frame_id frame_id = get_frame_id (frame);
+
+ c = allocate_piece_closure (ctx->num_pieces, ctx->pieces, ctx->gdbarch);
+ retval = allocate_computed_value (SYMBOL_TYPE (var),
+ &pieced_value_funcs,
+ c);
+ VALUE_FRAME_ID (retval) = frame_id;
}
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);
- set_value_stack (retval, 1);
- set_value_address (retval, address);
+ switch (ctx->location)
+ {
+ case DWARF_VALUE_REGISTER:
+ {
+ struct gdbarch *arch = get_frame_arch (frame);
+ 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);
+ }
+ break;
+
+ case DWARF_VALUE_MEMORY:
+ {
+ CORE_ADDR address = dwarf_expr_fetch (ctx, 0);
+ int in_stack_memory = dwarf_expr_fetch_in_stack_memory (ctx, 0);
+
+ retval = allocate_value (SYMBOL_TYPE (var));
+ VALUE_LVAL (retval) = lval_memory;
+ set_value_lazy (retval, 1);
+ if (in_stack_memory)
+ set_value_stack (retval, 1);
+ set_value_address (retval, address);
+ }
+ break;
+
+ case DWARF_VALUE_STACK:
+ {
+ ULONGEST value = (ULONGEST) dwarf_expr_fetch (ctx, 0);
+ bfd_byte *contents;
+ size_t n = ctx->addr_size;
+
+ retval = allocate_value (SYMBOL_TYPE (var));
+ contents = value_contents_raw (retval);
+ if (n > TYPE_LENGTH (SYMBOL_TYPE (var)))
+ n = TYPE_LENGTH (SYMBOL_TYPE (var));
+ store_unsigned_integer (contents, n,
+ gdbarch_byte_order (ctx->gdbarch),
+ value);
+ }
+ break;
+
+ case DWARF_VALUE_LITERAL:
+ {
+ bfd_byte *contents;
+ size_t n = ctx->len;
+
+ retval = allocate_value (SYMBOL_TYPE (var));
+ contents = value_contents_raw (retval);
+ if (n > TYPE_LENGTH (SYMBOL_TYPE (var)))
+ n = TYPE_LENGTH (SYMBOL_TYPE (var));
+ memcpy (contents, ctx->data, n);
+ }
+ break;
+
+ default:
+ internal_error (__FILE__, __LINE__, _("invalid location type"));
+ }
}
set_value_initialized (retval, ctx->initialized);
return retval;
}
-
-
-
-
\f
/* Helper functions and baton for dwarf2_loc_desc_needs_frame. */
nf_baton->needs_frame = 1;
}
+/* CFA accesses require a frame. */
+
+static CORE_ADDR
+needs_frame_frame_cfa (void *baton)
+{
+ struct needs_frame_baton *nf_baton = baton;
+ nf_baton->needs_frame = 1;
+ return 1;
+}
+
/* Thread-local accesses do require a frame. */
static CORE_ADDR
needs_frame_tls_address (void *baton, CORE_ADDR offset)
ctx->read_reg = needs_frame_read_reg;
ctx->read_mem = needs_frame_read_mem;
ctx->get_frame_base = needs_frame_frame_base;
+ ctx->get_frame_cfa = needs_frame_frame_cfa;
ctx->get_tls_address = needs_frame_tls_address;
dwarf_expr_eval (ctx, data, size);
- in_reg = ctx->in_reg;
+ in_reg = ctx->location == DWARF_VALUE_REGISTER;
if (ctx->num_pieces > 0)
{
/* If the location has several pieces, and any of them are in
registers, then we will need a frame to fetch them from. */
for (i = 0; i < ctx->num_pieces; i++)
- if (ctx->pieces[i].in_reg)
+ if (ctx->pieces[i].location == DWARF_VALUE_REGISTER)
in_reg = 1;
}
}
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;
+ struct block *b;
+ struct symbol *framefunc;
+ int frame_reg = 0;
LONGEST frame_offset;
gdb_byte *buf_end;
+ gdb_byte *base_data;
+ size_t base_size;
+ LONGEST base_offset = 0;
+
+ b = block_for_pc (ax->scope);
+
+ if (!b)
+ error (_("No block found for address"));
+
+ framefunc = block_linkage_function (b);
+
+ if (!framefunc)
+ error (_("No function found for block"));
+
+ dwarf_expr_frame_base_1 (framefunc, ax->scope,
+ &base_data, &base_size);
+
+ if (base_data[0] >= DW_OP_breg0
+ && base_data[0] <= DW_OP_breg31)
+ {
+ frame_reg = base_data[0] - DW_OP_breg0;
+ buf_end = read_sleb128 (base_data + 1, base_data + base_size, &base_offset);
+ if (buf_end != base_data + base_size)
+ error (_("Unexpected opcode after DW_OP_breg%u for symbol \"%s\"."),
+ frame_reg, SYMBOL_PRINT_NAME (symbol));
+ }
+ else
+ {
+ /* We don't know what to do with the frame base expression,
+ so we can't trace this variable; give up. */
+ error (_("Cannot generate expression to collect symbol \"%s\"; DWARF 2 encoding not handled"),
+ SYMBOL_PRINT_NAME (symbol));
+ }
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));
- gdbarch_virtual_frame_pointer (gdbarch,
- ax->scope, &frame_reg, &frame_offset);
ax_reg (ax, frame_reg);
- ax_const_l (ax, frame_offset);
+ ax_const_l (ax, base_offset + frame_offset);
ax_simple (ax, aop_add);
value->kind = axs_lvalue_memory;
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