@@ -942,8 +942,8 @@ static const char *namespace_name (struct die_info *die,
static void process_enumeration_scope (struct die_info *, struct dwarf2_cu *);
-static CORE_ADDR decode_locdesc (struct dwarf_block *, struct dwarf2_cu *,
- bool * = nullptr);
+static bool decode_locdesc (struct dwarf_block *, struct dwarf2_cu *,
+ CORE_ADDR *addr);
static enum dwarf_array_dim_ordering read_array_order (struct die_info *,
struct dwarf2_cu *);
@@ -11457,6 +11457,7 @@ handle_member_location (struct die_info *die, struct dwarf2_cu *cu,
if (attr != NULL)
{
*offset = 0;
+ CORE_ADDR temp;
/* Note that we do not check for a section offset first here.
This is because DW_AT_data_member_location is new in DWARF 4,
@@ -11466,8 +11467,11 @@ handle_member_location (struct die_info *die, struct dwarf2_cu *cu,
*offset = attr->constant_value (0);
else if (attr->form_is_section_offset ())
dwarf2_complex_location_expr_complaint ();
- else if (attr->form_is_block ())
- *offset = decode_locdesc (attr->as_block (), cu);
+ else if (attr->form_is_block ()
+ && decode_locdesc (attr->as_block (), cu, &temp))
+ {
+ *offset = temp;
+ }
else
dwarf2_complex_location_expr_complaint ();
@@ -11520,9 +11524,8 @@ handle_member_location (struct die_info *die, struct dwarf2_cu *cu,
dwarf2_complex_location_expr_complaint ();
else if (attr->form_is_block ())
{
- bool handled;
- CORE_ADDR offset = decode_locdesc (attr->as_block (), cu, &handled);
- if (handled)
+ CORE_ADDR offset;
+ if (decode_locdesc (attr->as_block (), cu, &offset))
field->set_loc_bitpos (offset * bits_per_byte);
else
{
@@ -12242,18 +12245,25 @@ dwarf2_add_member_fn (struct field_info *fip, struct die_info *die,
if (attr->form_is_block () && attr->as_block ()->size > 0)
{
struct dwarf_block *block = attr->as_block ();
+ CORE_ADDR offset;
- if (block->data[0] == DW_OP_constu)
+ if (block->data[0] == DW_OP_constu
+ && decode_locdesc (block, cu, &offset))
{
- /* Old-style GCC. */
- fnp->voffset = decode_locdesc (block, cu) + 2;
+ /* "Old"-style GCC. See
+ https://gcc.gnu.org/bugzilla/show_bug.cgi?id=44126
+ for discussion. This was known and a patch available
+ in 2010, but as of 2023, both GCC and clang still
+ emit this. */
+ fnp->voffset = offset + 2;
}
- else if (block->data[0] == DW_OP_deref
- || (block->size > 1
- && block->data[0] == DW_OP_deref_size
- && block->data[1] == cu->header.addr_size))
+ else if ((block->data[0] == DW_OP_deref
+ || (block->size > 1
+ && block->data[0] == DW_OP_deref_size
+ && block->data[1] == cu->header.addr_size))
+ && decode_locdesc (block, cu, &offset))
{
- fnp->voffset = decode_locdesc (block, cu);
+ fnp->voffset = offset;
if ((fnp->voffset % cu->header.addr_size) != 0)
dwarf2_complex_location_expr_complaint ();
else
@@ -16211,9 +16221,10 @@ cooked_indexer::scan_attributes (dwarf2_per_cu_data *scanning_per_cu,
if (!scanning_per_cu->addresses_seen && attr.form_is_block ())
{
struct dwarf_block *locdesc = attr.as_block ();
- CORE_ADDR addr = decode_locdesc (locdesc, reader->cu);
- if (addr != 0
- || reader->cu->per_objfile->per_bfd->has_section_at_zero)
+ CORE_ADDR addr;
+ if (decode_locdesc (locdesc, reader->cu, &addr)
+ && (addr != 0
+ || reader->cu->per_objfile->per_bfd->has_section_at_zero))
{
low_pc = addr;
/* For variables, we don't want to try decoding the
@@ -20911,14 +20922,34 @@ read_signatured_type (signatured_type *sig_type,
}
/* Decode simple location descriptions.
- Given a pointer to a dwarf block that defines a location, compute
- the location and return the value. If COMPUTED is non-null, it is
- set to true to indicate that decoding was successful, and false
- otherwise. If COMPUTED is null, then this function may emit a
- complaint. */
-static CORE_ADDR
-decode_locdesc (struct dwarf_block *blk, struct dwarf2_cu *cu, bool *computed)
+ Given a pointer to a DWARF block that defines a location, compute
+ the location. Returns true if the expression was computable by
+ this function, false otherwise. On a true return, *RESULT is set.
+
+ Note that this function does not implement a full DWARF expression
+ evaluator. Instead, it is used for a few limited purposes:
+
+ - Getting the address of a symbol that has a constant address. For
+ example, if a symbol has a location like "DW_OP_addr", the address
+ can be extracted.
+
+ - Getting the offset of a virtual function in its vtable. There
+ are two forms of this, one of which involves DW_OP_deref -- so this
+ function handles derefs in a peculiar way to make this 'work'.
+ (Probably this area should be rewritten.)
+
+ - Getting the offset of a field, when it is constant.
+
+ Opcodes that cannot be part of a constant expression, for example
+ those involving registers, simply result in a return of
+ 'false'.
+
+ This function may emit a complaint. */
+
+static bool
+decode_locdesc (struct dwarf_block *blk, struct dwarf2_cu *cu,
+ CORE_ADDR *result)
{
struct objfile *objfile = cu->per_objfile->objfile;
size_t i;
@@ -20926,12 +20957,10 @@ decode_locdesc (struct dwarf_block *blk, struct dwarf2_cu *cu, bool *computed)
const gdb_byte *data = blk->data;
CORE_ADDR stack[64];
int stacki;
- unsigned int bytes_read, unsnd;
+ unsigned int bytes_read;
gdb_byte op;
- if (computed != nullptr)
- *computed = false;
-
+ *result = 0;
i = 0;
stacki = 0;
stack[stacki] = 0;
@@ -20977,61 +21006,6 @@ decode_locdesc (struct dwarf_block *blk, struct dwarf2_cu *cu, bool *computed)
stack[++stacki] = op - DW_OP_lit0;
break;
- 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:
- stack[++stacki] = op - DW_OP_reg0;
- if (i < size)
- {
- if (computed == nullptr)
- dwarf2_complex_location_expr_complaint ();
- else
- return 0;
- }
- break;
-
- case DW_OP_regx:
- unsnd = read_unsigned_leb128 (NULL, (data + i), &bytes_read);
- i += bytes_read;
- stack[++stacki] = unsnd;
- if (i < size)
- {
- if (computed == nullptr)
- dwarf2_complex_location_expr_complaint ();
- else
- return 0;
- }
- break;
-
case DW_OP_addr:
stack[++stacki] = cu->header.read_address (objfile->obfd.get (),
&data[i],
@@ -21112,37 +21086,7 @@ decode_locdesc (struct dwarf_block *blk, struct dwarf2_cu *cu, bool *computed)
global symbols, although the variable's address will be bogus
in the psymtab. */
if (i < size)
- {
- if (computed == nullptr)
- dwarf2_complex_location_expr_complaint ();
- else
- return 0;
- }
- break;
-
- case DW_OP_GNU_push_tls_address:
- case DW_OP_form_tls_address:
- /* The top of the stack has the offset from the beginning
- of the thread control block at which the variable is located. */
- /* Nothing should follow this operator, so the top of stack would
- be returned. */
- /* This is valid for partial global symbols, but the variable's
- address will be bogus in the psymtab. Make it always at least
- non-zero to not look as a variable garbage collected by linker
- which have DW_OP_addr 0. */
- if (i < size)
- {
- if (computed == nullptr)
- dwarf2_complex_location_expr_complaint ();
- else
- return 0;
- }
- stack[stacki]++;
- break;
-
- case DW_OP_GNU_uninit:
- if (computed != nullptr)
- return 0;
+ return false;
break;
case DW_OP_addrx:
@@ -21154,41 +21098,26 @@ decode_locdesc (struct dwarf_block *blk, struct dwarf2_cu *cu, bool *computed)
break;
default:
- if (computed == nullptr)
- {
- const char *name = get_DW_OP_name (op);
-
- if (name)
- complaint (_("unsupported stack op: '%s'"),
- name);
- else
- complaint (_("unsupported stack op: '%02x'"),
- op);
- }
-
- return (stack[stacki]);
+ return false;
}
/* Enforce maximum stack depth of SIZE-1 to avoid writing
outside of the allocated space. Also enforce minimum>0. */
if (stacki >= ARRAY_SIZE (stack) - 1)
{
- if (computed == nullptr)
- complaint (_("location description stack overflow"));
- return 0;
+ complaint (_("location description stack overflow"));
+ return false;
}
if (stacki <= 0)
{
- if (computed == nullptr)
- complaint (_("location description stack underflow"));
- return 0;
+ complaint (_("location description stack underflow"));
+ return false;
}
}
- if (computed != nullptr)
- *computed = true;
- return (stack[stacki]);
+ *result = stack[stacki];
+ return true;
}
/* memory allocation interface */