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dwarf2expr.c
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/* DWARF 2 Expression Evaluator.
Copyright (C) 2001-2015 Free Software Foundation, Inc.
Contributed by Daniel Berlin ([email protected])
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "symtab.h"
#include "gdbtypes.h"
#include "value.h"
#include "gdbcore.h"
#include "dwarf2.h"
#include "dwarf2expr.h"
#include <gdb_proc_service.h> /* XXX */
/* Local prototypes. */
static void execute_stack_op (struct dwarf_expr_context *,
const gdb_byte *, const gdb_byte *);
/* Cookie for gdbarch data. */
static struct gdbarch_data *dwarf_arch_cookie;
/* This holds gdbarch-specific types used by the DWARF expression
evaluator. See comments in execute_stack_op. */
struct dwarf_gdbarch_types
{
struct type *dw_types[3];
};
/* Allocate and fill in dwarf_gdbarch_types for an arch. */
static void *
dwarf_gdbarch_types_init (struct gdbarch *gdbarch)
{
struct dwarf_gdbarch_types *types
= GDBARCH_OBSTACK_ZALLOC (gdbarch, struct dwarf_gdbarch_types);
/* The types themselves are lazily initialized. */
return types;
}
/* Return the type used for DWARF operations where the type is
unspecified in the DWARF spec. Only certain sizes are
supported. */
static struct type *
dwarf_expr_address_type (struct dwarf_expr_context *ctx)
{
struct dwarf_gdbarch_types *types = gdbarch_data (ctx->gdbarch,
dwarf_arch_cookie);
int ndx;
if (ctx->addr_size == 2)
ndx = 0;
else if (ctx->addr_size == 4)
ndx = 1;
else if (ctx->addr_size == 8)
ndx = 2;
else
error (_("Unsupported address size in DWARF expressions: %d bits"),
8 * ctx->addr_size);
if (types->dw_types[ndx] == NULL)
types->dw_types[ndx]
= arch_integer_type (ctx->gdbarch,
8 * ctx->addr_size,
0, "<signed DWARF address type>");
return types->dw_types[ndx];
}
/* Create a new context for the expression evaluator. */
struct dwarf_expr_context *
new_dwarf_expr_context (void)
{
struct dwarf_expr_context *retval;
retval = XCNEW (struct dwarf_expr_context);
retval->stack_len = 0;
retval->stack_allocated = 10;
retval->stack = XNEWVEC (struct dwarf_stack_value, retval->stack_allocated);
retval->num_pieces = 0;
retval->pieces = 0;
retval->max_recursion_depth = 0x100;
return retval;
}
/* Release the memory allocated to CTX. */
void
free_dwarf_expr_context (struct dwarf_expr_context *ctx)
{
xfree (ctx->stack);
xfree (ctx->pieces);
xfree (ctx);
}
/* Helper for make_cleanup_free_dwarf_expr_context. */
static void
free_dwarf_expr_context_cleanup (void *arg)
{
free_dwarf_expr_context (arg);
}
/* Return a cleanup that calls free_dwarf_expr_context. */
struct cleanup *
make_cleanup_free_dwarf_expr_context (struct dwarf_expr_context *ctx)
{
return make_cleanup (free_dwarf_expr_context_cleanup, ctx);
}
/* Expand the memory allocated to CTX's stack to contain at least
NEED more elements than are currently used. */
static void
dwarf_expr_grow_stack (struct dwarf_expr_context *ctx, size_t need)
{
if (ctx->stack_len + need > ctx->stack_allocated)
{
size_t newlen = ctx->stack_len + need + 10;
ctx->stack = xrealloc (ctx->stack,
newlen * sizeof (struct dwarf_stack_value));
ctx->stack_allocated = newlen;
}
}
/* Push VALUE onto CTX's stack. */
static void
dwarf_expr_push (struct dwarf_expr_context *ctx, struct value *value,
int in_stack_memory)
{
struct dwarf_stack_value *v;
dwarf_expr_grow_stack (ctx, 1);
v = &ctx->stack[ctx->stack_len++];
v->value = value;
v->in_stack_memory = in_stack_memory;
}
/* Push VALUE onto CTX's stack. */
void
dwarf_expr_push_address (struct dwarf_expr_context *ctx, CORE_ADDR value,
int in_stack_memory)
{
dwarf_expr_push (ctx,
value_from_ulongest (dwarf_expr_address_type (ctx), value),
in_stack_memory);
}
/* Pop the top item off of CTX's stack. */
static void
dwarf_expr_pop (struct dwarf_expr_context *ctx)
{
if (ctx->stack_len <= 0)
error (_("dwarf expression stack underflow"));
ctx->stack_len--;
}
/* Retrieve the N'th item on CTX's stack. */
struct value *
dwarf_expr_fetch (struct dwarf_expr_context *ctx, int n)
{
if (ctx->stack_len <= n)
error (_("Asked for position %d of stack, "
"stack only has %d elements on it."),
n, ctx->stack_len);
return ctx->stack[ctx->stack_len - (1 + n)].value;
}
/* Require that TYPE be an integral type; throw an exception if not. */
static void
dwarf_require_integral (struct type *type)
{
if (TYPE_CODE (type) != TYPE_CODE_INT
&& TYPE_CODE (type) != TYPE_CODE_CHAR
&& TYPE_CODE (type) != TYPE_CODE_BOOL)
error (_("integral type expected in DWARF expression"));
}
/* Return the unsigned form of TYPE. TYPE is necessarily an integral
type. */
static struct type *
get_unsigned_type (struct gdbarch *gdbarch, struct type *type)
{
switch (TYPE_LENGTH (type))
{
case 1:
return builtin_type (gdbarch)->builtin_uint8;
case 2:
return builtin_type (gdbarch)->builtin_uint16;
case 4:
return builtin_type (gdbarch)->builtin_uint32;
case 8:
return builtin_type (gdbarch)->builtin_uint64;
default:
error (_("no unsigned variant found for type, while evaluating "
"DWARF expression"));
}
}
/* Return the signed form of TYPE. TYPE is necessarily an integral
type. */
static struct type *
get_signed_type (struct gdbarch *gdbarch, struct type *type)
{
switch (TYPE_LENGTH (type))
{
case 1:
return builtin_type (gdbarch)->builtin_int8;
case 2:
return builtin_type (gdbarch)->builtin_int16;
case 4:
return builtin_type (gdbarch)->builtin_int32;
case 8:
return builtin_type (gdbarch)->builtin_int64;
default:
error (_("no signed variant found for type, while evaluating "
"DWARF expression"));
}
}
/* Retrieve the N'th item on CTX's stack, converted to an address. */
CORE_ADDR
dwarf_expr_fetch_address (struct dwarf_expr_context *ctx, int n)
{
struct value *result_val = dwarf_expr_fetch (ctx, n);
enum bfd_endian byte_order = gdbarch_byte_order (ctx->gdbarch);
ULONGEST result;
dwarf_require_integral (value_type (result_val));
result = extract_unsigned_integer (value_contents (result_val),
TYPE_LENGTH (value_type (result_val)),
byte_order);
/* For most architectures, calling extract_unsigned_integer() alone
is sufficient for extracting an address. However, some
architectures (e.g. MIPS) use signed addresses and using
extract_unsigned_integer() will not produce a correct
result. Make sure we invoke gdbarch_integer_to_address()
for those architectures which require it. */
if (gdbarch_integer_to_address_p (ctx->gdbarch))
{
gdb_byte *buf = alloca (ctx->addr_size);
struct type *int_type = get_unsigned_type (ctx->gdbarch,
value_type (result_val));
store_unsigned_integer (buf, ctx->addr_size, byte_order, result);
return gdbarch_integer_to_address (ctx->gdbarch, int_type, buf);
}
return (CORE_ADDR) result;
}
/* Retrieve the in_stack_memory flag of the N'th item on CTX's stack. */
int
dwarf_expr_fetch_in_stack_memory (struct dwarf_expr_context *ctx, int n)
{
if (ctx->stack_len <= n)
error (_("Asked for position %d of stack, "
"stack only has %d elements on it."),
n, ctx->stack_len);
return ctx->stack[ctx->stack_len - (1 + n)].in_stack_memory;
}
/* Return true if the expression stack is empty. */
static int
dwarf_expr_stack_empty_p (struct dwarf_expr_context *ctx)
{
return ctx->stack_len == 0;
}
/* Add a new piece to CTX's piece list. */
static void
add_piece (struct dwarf_expr_context *ctx, ULONGEST size, ULONGEST offset)
{
struct dwarf_expr_piece *p;
ctx->num_pieces++;
ctx->pieces = xrealloc (ctx->pieces,
(ctx->num_pieces
* sizeof (struct dwarf_expr_piece)));
p = &ctx->pieces[ctx->num_pieces - 1];
p->location = ctx->location;
p->size = size;
p->offset = offset;
if (p->location == DWARF_VALUE_LITERAL)
{
p->v.literal.data = ctx->data;
p->v.literal.length = ctx->len;
}
else if (dwarf_expr_stack_empty_p (ctx))
{
p->location = DWARF_VALUE_OPTIMIZED_OUT;
/* Also reset the context's location, for our callers. This is
a somewhat strange approach, but this lets us avoid setting
the location to DWARF_VALUE_MEMORY in all the individual
cases in the evaluator. */
ctx->location = DWARF_VALUE_OPTIMIZED_OUT;
}
else if (p->location == DWARF_VALUE_MEMORY)
{
p->v.mem.addr = dwarf_expr_fetch_address (ctx, 0);
p->v.mem.in_stack_memory = dwarf_expr_fetch_in_stack_memory (ctx, 0);
}
else if (p->location == DWARF_VALUE_IMPLICIT_POINTER)
{
p->v.ptr.die.sect_off = ctx->len;
p->v.ptr.offset = value_as_long (dwarf_expr_fetch (ctx, 0));
}
else if (p->location == DWARF_VALUE_REGISTER)
p->v.regno = value_as_long (dwarf_expr_fetch (ctx, 0));
else
{
p->v.value = dwarf_expr_fetch (ctx, 0);
}
}
/* Evaluate the expression at ADDR (LEN bytes long) using the context
CTX. */
void
dwarf_expr_eval (struct dwarf_expr_context *ctx, const gdb_byte *addr,
size_t len)
{
int old_recursion_depth = ctx->recursion_depth;
execute_stack_op (ctx, addr, addr + len);
/* CTX RECURSION_DEPTH becomes invalid if an exception was thrown here. */
gdb_assert (ctx->recursion_depth == old_recursion_depth);
}
/* Helper to read a uleb128 value or throw an error. */
const gdb_byte *
safe_read_uleb128 (const gdb_byte *buf, const gdb_byte *buf_end,
uint64_t *r)
{
buf = gdb_read_uleb128 (buf, buf_end, r);
if (buf == NULL)
error (_("DWARF expression error: ran off end of buffer reading uleb128 value"));
return buf;
}
/* Helper to read a sleb128 value or throw an error. */
const gdb_byte *
safe_read_sleb128 (const gdb_byte *buf, const gdb_byte *buf_end,
int64_t *r)
{
buf = gdb_read_sleb128 (buf, buf_end, r);
if (buf == NULL)
error (_("DWARF expression error: ran off end of buffer reading sleb128 value"));
return buf;
}
const gdb_byte *
safe_skip_leb128 (const gdb_byte *buf, const gdb_byte *buf_end)
{
buf = gdb_skip_leb128 (buf, buf_end);
if (buf == NULL)
error (_("DWARF expression error: ran off end of buffer reading leb128 value"));
return buf;
}
/* Check that the current operator is either at the end of an
expression, or that it is followed by a composition operator. */
void
dwarf_expr_require_composition (const gdb_byte *op_ptr, const gdb_byte *op_end,
const char *op_name)
{
/* It seems like DW_OP_GNU_uninit should be handled here. However,
it doesn't seem to make sense for DW_OP_*_value, and it was not
checked at the other place that this function is called. */
if (op_ptr != op_end && *op_ptr != DW_OP_piece && *op_ptr != DW_OP_bit_piece)
error (_("DWARF-2 expression error: `%s' operations must be "
"used either alone or in conjunction with DW_OP_piece "
"or DW_OP_bit_piece."),
op_name);
}
/* Return true iff the types T1 and T2 are "the same". This only does
checks that might reasonably be needed to compare DWARF base
types. */
static int
base_types_equal_p (struct type *t1, struct type *t2)
{
if (TYPE_CODE (t1) != TYPE_CODE (t2))
return 0;
if (TYPE_UNSIGNED (t1) != TYPE_UNSIGNED (t2))
return 0;
return TYPE_LENGTH (t1) == TYPE_LENGTH (t2);
}
/* A convenience function to call get_base_type on CTX and return the
result. DIE is the DIE whose type we need. SIZE is non-zero if
this function should verify that the resulting type has the correct
size. */
static struct type *
dwarf_get_base_type (struct dwarf_expr_context *ctx, cu_offset die, int size)
{
struct type *result;
if (ctx->funcs->get_base_type)
{
result = ctx->funcs->get_base_type (ctx, die);
if (result == NULL)
error (_("Could not find type for DW_OP_GNU_const_type"));
if (size != 0 && TYPE_LENGTH (result) != size)
error (_("DW_OP_GNU_const_type has different sizes for type and data"));
}
else
/* Anything will do. */
result = builtin_type (ctx->gdbarch)->builtin_int;
return result;
}
/* If <BUF..BUF_END] contains DW_FORM_block* with single DW_OP_reg* return the
DWARF register number. Otherwise return -1. */
int
dwarf_block_to_dwarf_reg (const gdb_byte *buf, const gdb_byte *buf_end)
{
uint64_t dwarf_reg;
if (buf_end <= buf)
return -1;
if (*buf >= DW_OP_reg0 && *buf <= DW_OP_reg31)
{
if (buf_end - buf != 1)
return -1;
return *buf - DW_OP_reg0;
}
if (*buf == DW_OP_GNU_regval_type)
{
buf++;
buf = gdb_read_uleb128 (buf, buf_end, &dwarf_reg);
if (buf == NULL)
return -1;
buf = gdb_skip_leb128 (buf, buf_end);
if (buf == NULL)
return -1;
}
else if (*buf == DW_OP_regx)
{
buf++;
buf = gdb_read_uleb128 (buf, buf_end, &dwarf_reg);
if (buf == NULL)
return -1;
}
else
return -1;
if (buf != buf_end || (int) dwarf_reg != dwarf_reg)
return -1;
return dwarf_reg;
}
/* If <BUF..BUF_END] contains DW_FORM_block* with just DW_OP_breg*(0) and
DW_OP_deref* return the DWARF register number. Otherwise return -1.
DEREF_SIZE_RETURN contains -1 for DW_OP_deref; otherwise it contains the
size from DW_OP_deref_size. */
int
dwarf_block_to_dwarf_reg_deref (const gdb_byte *buf, const gdb_byte *buf_end,
CORE_ADDR *deref_size_return)
{
uint64_t dwarf_reg;
int64_t offset;
if (buf_end <= buf)
return -1;
if (*buf >= DW_OP_breg0 && *buf <= DW_OP_breg31)
{
dwarf_reg = *buf - DW_OP_breg0;
buf++;
if (buf >= buf_end)
return -1;
}
else if (*buf == DW_OP_bregx)
{
buf++;
buf = gdb_read_uleb128 (buf, buf_end, &dwarf_reg);
if (buf == NULL)
return -1;
if ((int) dwarf_reg != dwarf_reg)
return -1;
}
else
return -1;
buf = gdb_read_sleb128 (buf, buf_end, &offset);
if (buf == NULL)
return -1;
if (offset != 0)
return -1;
if (*buf == DW_OP_deref)
{
buf++;
*deref_size_return = -1;
}
else if (*buf == DW_OP_deref_size)
{
buf++;
if (buf >= buf_end)
return -1;
*deref_size_return = *buf++;
}
else
return -1;
if (buf != buf_end)
return -1;
return dwarf_reg;
}
/* If <BUF..BUF_END] contains DW_FORM_block* with single DW_OP_fbreg(X) fill
in FB_OFFSET_RETURN with the X offset and return 1. Otherwise return 0. */
int
dwarf_block_to_fb_offset (const gdb_byte *buf, const gdb_byte *buf_end,
CORE_ADDR *fb_offset_return)
{
int64_t fb_offset;
if (buf_end <= buf)
return 0;
if (*buf != DW_OP_fbreg)
return 0;
buf++;
buf = gdb_read_sleb128 (buf, buf_end, &fb_offset);
if (buf == NULL)
return 0;
*fb_offset_return = fb_offset;
if (buf != buf_end || fb_offset != (LONGEST) *fb_offset_return)
return 0;
return 1;
}
/* If <BUF..BUF_END] contains DW_FORM_block* with single DW_OP_bregSP(X) fill
in SP_OFFSET_RETURN with the X offset and return 1. Otherwise return 0.
The matched SP register number depends on GDBARCH. */
int
dwarf_block_to_sp_offset (struct gdbarch *gdbarch, const gdb_byte *buf,
const gdb_byte *buf_end, CORE_ADDR *sp_offset_return)
{
uint64_t dwarf_reg;
int64_t sp_offset;
if (buf_end <= buf)
return 0;
if (*buf >= DW_OP_breg0 && *buf <= DW_OP_breg31)
{
dwarf_reg = *buf - DW_OP_breg0;
buf++;
}
else
{
if (*buf != DW_OP_bregx)
return 0;
buf++;
buf = gdb_read_uleb128 (buf, buf_end, &dwarf_reg);
if (buf == NULL)
return 0;
}
if (gdbarch_dwarf2_reg_to_regnum (gdbarch, dwarf_reg)
!= gdbarch_sp_regnum (gdbarch))
return 0;
buf = gdb_read_sleb128 (buf, buf_end, &sp_offset);
if (buf == NULL)
return 0;
*sp_offset_return = sp_offset;
if (buf != buf_end || sp_offset != (LONGEST) *sp_offset_return)
return 0;
return 1;
}
/* The engine for the expression evaluator. Using the context in CTX,
evaluate the expression between OP_PTR and OP_END. */
static void
execute_stack_op (struct dwarf_expr_context *ctx,
const gdb_byte *op_ptr, const gdb_byte *op_end)
{
enum bfd_endian byte_order = gdbarch_byte_order (ctx->gdbarch);
/* Old-style "untyped" DWARF values need special treatment in a
couple of places, specifically DW_OP_mod and DW_OP_shr. We need
a special type for these values so we can distinguish them from
values that have an explicit type, because explicitly-typed
values do not need special treatment. This special type must be
different (in the `==' sense) from any base type coming from the
CU. */
struct type *address_type = dwarf_expr_address_type (ctx);
ctx->location = DWARF_VALUE_MEMORY;
ctx->initialized = 1; /* Default is initialized. */
if (ctx->recursion_depth > ctx->max_recursion_depth)
error (_("DWARF-2 expression error: Loop detected (%d)."),
ctx->recursion_depth);
ctx->recursion_depth++;
while (op_ptr < op_end)
{
enum dwarf_location_atom op = (enum dwarf_location_atom) *op_ptr++;
ULONGEST result;
/* Assume the value is not in stack memory.
Code that knows otherwise sets this to 1.
Some arithmetic on stack addresses can probably be assumed to still
be a stack address, but we skip this complication for now.
This is just an optimization, so it's always ok to punt
and leave this as 0. */
int in_stack_memory = 0;
uint64_t uoffset, reg;
int64_t offset;
struct value *result_val = NULL;
/* The DWARF expression might have a bug causing an infinite
loop. In that case, quitting is the only way out. */
QUIT;
{
/* XXX */
extern int debug_infinity;
if (debug_infinity)
debug_printf ("\t\x1B[35m%s\x1B[0m\n", get_DW_OP_name (op));
}
switch (op)
{
case DW_OP_lit0:
case DW_OP_lit1:
case DW_OP_lit2:
case DW_OP_lit3:
case DW_OP_lit4:
case DW_OP_lit5:
case DW_OP_lit6:
case DW_OP_lit7:
case DW_OP_lit8:
case DW_OP_lit9:
case DW_OP_lit10:
case DW_OP_lit11:
case DW_OP_lit12:
case DW_OP_lit13:
case DW_OP_lit14:
case DW_OP_lit15:
case DW_OP_lit16:
case DW_OP_lit17:
case DW_OP_lit18:
case DW_OP_lit19:
case DW_OP_lit20:
case DW_OP_lit21:
case DW_OP_lit22:
case DW_OP_lit23:
case DW_OP_lit24:
case DW_OP_lit25:
case DW_OP_lit26:
case DW_OP_lit27:
case DW_OP_lit28:
case DW_OP_lit29:
case DW_OP_lit30:
case DW_OP_lit31:
result = op - DW_OP_lit0;
result_val = value_from_ulongest (address_type, result);
break;
case DW_OP_addr:
result = extract_unsigned_integer (op_ptr,
ctx->addr_size, byte_order);
op_ptr += ctx->addr_size;
/* Some versions of GCC emit DW_OP_addr before
DW_OP_GNU_push_tls_address. In this case the value is an
index, not an address. We don't support things like
branching between the address and the TLS op. */
if (op_ptr >= op_end || *op_ptr != DW_OP_GNU_push_tls_address)
result += ctx->offset;
result_val = value_from_ulongest (address_type, result);
break;
case DW_OP_GNU_addr_index:
op_ptr = safe_read_uleb128 (op_ptr, op_end, &uoffset);
result = (ctx->funcs->get_addr_index) (ctx->baton, uoffset);
result += ctx->offset;
result_val = value_from_ulongest (address_type, result);
break;
case DW_OP_GNU_const_index:
op_ptr = safe_read_uleb128 (op_ptr, op_end, &uoffset);
result = (ctx->funcs->get_addr_index) (ctx->baton, uoffset);
result_val = value_from_ulongest (address_type, result);
break;
case DW_OP_const1u:
result = extract_unsigned_integer (op_ptr, 1, byte_order);
result_val = value_from_ulongest (address_type, result);
op_ptr += 1;
break;
case DW_OP_const1s:
result = extract_signed_integer (op_ptr, 1, byte_order);
result_val = value_from_ulongest (address_type, result);
op_ptr += 1;
break;
case DW_OP_const2u:
result = extract_unsigned_integer (op_ptr, 2, byte_order);
result_val = value_from_ulongest (address_type, result);
op_ptr += 2;
break;
case DW_OP_const2s:
result = extract_signed_integer (op_ptr, 2, byte_order);
result_val = value_from_ulongest (address_type, result);
op_ptr += 2;
break;
case DW_OP_const4u:
result = extract_unsigned_integer (op_ptr, 4, byte_order);
result_val = value_from_ulongest (address_type, result);
op_ptr += 4;
break;
case DW_OP_const4s:
result = extract_signed_integer (op_ptr, 4, byte_order);
result_val = value_from_ulongest (address_type, result);
op_ptr += 4;
break;
case DW_OP_const8u:
result = extract_unsigned_integer (op_ptr, 8, byte_order);
result_val = value_from_ulongest (address_type, result);
op_ptr += 8;
break;
case DW_OP_const8s:
result = extract_signed_integer (op_ptr, 8, byte_order);
result_val = value_from_ulongest (address_type, result);
op_ptr += 8;
break;
case DW_OP_constu:
op_ptr = safe_read_uleb128 (op_ptr, op_end, &uoffset);
result = uoffset;
result_val = value_from_ulongest (address_type, result);
break;
case DW_OP_consts:
op_ptr = safe_read_sleb128 (op_ptr, op_end, &offset);
result = offset;
result_val = value_from_ulongest (address_type, result);
break;
/* The DW_OP_reg operations are required to occur alone in
location expressions. */
case DW_OP_reg0:
case DW_OP_reg1:
case DW_OP_reg2:
case DW_OP_reg3:
case DW_OP_reg4:
case DW_OP_reg5:
case DW_OP_reg6:
case DW_OP_reg7:
case DW_OP_reg8:
case DW_OP_reg9:
case DW_OP_reg10:
case DW_OP_reg11:
case DW_OP_reg12:
case DW_OP_reg13:
case DW_OP_reg14:
case DW_OP_reg15:
case DW_OP_reg16:
case DW_OP_reg17:
case DW_OP_reg18:
case DW_OP_reg19:
case DW_OP_reg20:
case DW_OP_reg21:
case DW_OP_reg22:
case DW_OP_reg23:
case DW_OP_reg24:
case DW_OP_reg25:
case DW_OP_reg26:
case DW_OP_reg27:
case DW_OP_reg28:
case DW_OP_reg29:
case DW_OP_reg30:
case DW_OP_reg31:
if (op_ptr != op_end
&& *op_ptr != DW_OP_piece
&& *op_ptr != DW_OP_bit_piece
&& *op_ptr != DW_OP_GNU_uninit)
error (_("DWARF-2 expression error: DW_OP_reg operations must be "
"used either alone or in conjunction with DW_OP_piece "
"or DW_OP_bit_piece."));
result = op - DW_OP_reg0;
result_val = value_from_ulongest (address_type, result);
ctx->location = DWARF_VALUE_REGISTER;
break;
case DW_OP_regx:
op_ptr = safe_read_uleb128 (op_ptr, op_end, ®);
dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_regx");
result = reg;
result_val = value_from_ulongest (address_type, result);
ctx->location = DWARF_VALUE_REGISTER;
break;
case DW_OP_implicit_value:
{
uint64_t len;
op_ptr = safe_read_uleb128 (op_ptr, op_end, &len);
if (op_ptr + len > op_end)
error (_("DW_OP_implicit_value: too few bytes available."));
ctx->len = len;
ctx->data = op_ptr;
ctx->location = DWARF_VALUE_LITERAL;
op_ptr += len;
dwarf_expr_require_composition (op_ptr, op_end,
"DW_OP_implicit_value");
}
goto no_push;
case DW_OP_stack_value:
ctx->location = DWARF_VALUE_STACK;
dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_stack_value");
goto no_push;
case DW_OP_GNU_implicit_pointer:
{
int64_t len;
if (ctx->ref_addr_size == -1)
error (_("DWARF-2 expression error: DW_OP_GNU_implicit_pointer "
"is not allowed in frame context"));
/* The referred-to DIE of sect_offset kind. */
ctx->len = extract_unsigned_integer (op_ptr, ctx->ref_addr_size,
byte_order);
op_ptr += ctx->ref_addr_size;
/* The byte offset into the data. */
op_ptr = safe_read_sleb128 (op_ptr, op_end, &len);
result = (ULONGEST) len;
result_val = value_from_ulongest (address_type, result);
ctx->location = DWARF_VALUE_IMPLICIT_POINTER;
dwarf_expr_require_composition (op_ptr, op_end,
"DW_OP_GNU_implicit_pointer");
}
break;
case DW_OP_breg0:
case DW_OP_breg1:
case DW_OP_breg2:
case DW_OP_breg3:
case DW_OP_breg4:
case DW_OP_breg5:
case DW_OP_breg6:
case DW_OP_breg7:
case DW_OP_breg8:
case DW_OP_breg9:
case DW_OP_breg10:
case DW_OP_breg11:
case DW_OP_breg12:
case DW_OP_breg13:
case DW_OP_breg14:
case DW_OP_breg15:
case DW_OP_breg16:
case DW_OP_breg17:
case DW_OP_breg18:
case DW_OP_breg19:
case DW_OP_breg20:
case DW_OP_breg21:
case DW_OP_breg22:
case DW_OP_breg23:
case DW_OP_breg24:
case DW_OP_breg25:
case DW_OP_breg26:
case DW_OP_breg27:
case DW_OP_breg28:
case DW_OP_breg29:
case DW_OP_breg30:
case DW_OP_breg31:
{
op_ptr = safe_read_sleb128 (op_ptr, op_end, &offset);
result = (ctx->funcs->read_addr_from_reg) (ctx->baton,
op - DW_OP_breg0);
result += offset;
result_val = value_from_ulongest (address_type, result);
}
break;
case DW_OP_bregx:
{
op_ptr = safe_read_uleb128 (op_ptr, op_end, ®);
op_ptr = safe_read_sleb128 (op_ptr, op_end, &offset);
result = (ctx->funcs->read_addr_from_reg) (ctx->baton, reg);
result += offset;
result_val = value_from_ulongest (address_type, result);
}
break;
case DW_OP_fbreg:
{
const gdb_byte *datastart;
size_t datalen;
unsigned int before_stack_len;
op_ptr = safe_read_sleb128 (op_ptr, op_end, &offset);
/* Rather than create a whole new context, we simply
record the stack length before execution, then reset it
afterwards, effectively erasing whatever the recursive
call put there. */
before_stack_len = ctx->stack_len;
/* FIXME: cagney/2003-03-26: This code should be using
get_frame_base_address(), and then implement a dwarf2
specific this_base method. */
(ctx->funcs->get_frame_base) (ctx->baton, &datastart, &datalen);
dwarf_expr_eval (ctx, datastart, datalen);
if (ctx->location == DWARF_VALUE_MEMORY)
result = dwarf_expr_fetch_address (ctx, 0);
else if (ctx->location == DWARF_VALUE_REGISTER)
result = (ctx->funcs->read_addr_from_reg)
(ctx->baton,
value_as_long (dwarf_expr_fetch (ctx, 0)));
else
error (_("Not implemented: computing frame "
"base using explicit value operator"));
result = result + offset;
result_val = value_from_ulongest (address_type, result);
in_stack_memory = 1;
ctx->stack_len = before_stack_len;
ctx->location = DWARF_VALUE_MEMORY;
}
break;
case DW_OP_dup:
result_val = dwarf_expr_fetch (ctx, 0);
in_stack_memory = dwarf_expr_fetch_in_stack_memory (ctx, 0);
break;
case DW_OP_drop:
dwarf_expr_pop (ctx);
goto no_push;
case DW_OP_pick:
offset = *op_ptr++;
result_val = dwarf_expr_fetch (ctx, offset);
in_stack_memory = dwarf_expr_fetch_in_stack_memory (ctx, offset);
break;
case DW_OP_swap:
{
struct dwarf_stack_value t1, t2;
if (ctx->stack_len < 2)
error (_("Not enough elements for "