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* Makefile.in (dwarf2-frame.o): Add complaints_h.

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* dwarf2-frame.c: Include complaints.h.
        (decode_frame_entry_1): Rename from decode_frame_entry; tidy
        variable initialization; return NULL on error.
        (decode_frame_entry): New.
This commit is contained in:
Richard Henderson 2003-07-11 16:22:17 +00:00
parent c4a095243b
commit 6896c0c737
3 changed files with 138 additions and 18 deletions
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8
gdb/ChangeLog
View file

@ -1,3 +1,11 @@
2003-07-11 Richard Henderson <rth@redhat.com>
* Makefile.in (dwarf2-frame.o): Add complaints_h.
* dwarf2-frame.c: Include complaints.h.
(decode_frame_entry_1): Rename from decode_frame_entry; tidy
variable initialization; return NULL on error.
(decode_frame_entry): New.
2003-07-11 Andrew Cagney <cagney@redhat.com>
* frame.h (frame_address_in_block): Delete declaration.

2
gdb/Makefile.in
View file

@ -1680,7 +1680,7 @@ dwarf2loc.o: dwarf2loc.c $(defs_h) $(ui_out_h) $(value_h) $(frame_h) \
dwarf2-frame.o: $(defs_h) $(dwarf2expr_h) $(elf_dwarf2_h) $(frame_h) \
$(frame_base_h) $(frame_unwind_h) $(gdbcore_h) $(gdbtypes_h) \
$(symtab_h) $(objfiles_h) $(regcache_h) $(gdb_assert_h) \
$(gdb_string_h) $(dwarf2_frame_h)
$(gdb_string_h) $(dwarf2_frame_h) $(complaints_h)
dwarf2read.o: dwarf2read.c $(defs_h) $(bfd_h) $(symtab_h) $(gdbtypes_h) \
$(symfile_h) $(objfiles_h) $(elf_dwarf2_h) $(buildsym_h) \
$(demangle_h) $(expression_h) $(filenames_h) $(macrotab_h) \

146
gdb/dwarf2-frame.c
View file

@ -36,6 +36,7 @@
#include "gdb_assert.h"
#include "gdb_string.h"
#include "complaints.h"
#include "dwarf2-frame.h"
/* Call Frame Information (CFI). */
@ -1058,35 +1059,44 @@ add_fde (struct comp_unit *unit, struct dwarf2_fde *fde)
#define DW64_CIE_ID ~0
#endif
/* Read a CIE or FDE in BUF and decode it. */
static char *decode_frame_entry (struct comp_unit *unit, char *start,
int eh_frame_p);
/* Decode the next CIE or FDE. Return NULL if invalid input, otherwise
the next byte to be processed. */
static char *
decode_frame_entry (struct comp_unit *unit, char *buf, int eh_frame_p)
decode_frame_entry_1 (struct comp_unit *unit, char *start, int eh_frame_p)
{
char *buf;
LONGEST length;
unsigned int bytes_read;
int dwarf64_p = 0;
ULONGEST cie_id = DW_CIE_ID;
int dwarf64_p;
ULONGEST cie_id;
ULONGEST cie_pointer;
char *start = buf;
char *end;
buf = start;
length = read_initial_length (unit->abfd, buf, &bytes_read);
buf += bytes_read;
end = buf + length;
/* Are we still within the section? */
if (end > unit->dwarf_frame_buffer + unit->dwarf_frame_size)
return NULL;
if (length == 0)
return end;
if (bytes_read == 12)
dwarf64_p = 1;
/* Distinguish between 32 and 64-bit encoded frame info. */
dwarf64_p = (bytes_read == 12);
/* In a .eh_frame section, zero is used to distinguish CIEs from
FDEs. */
/* In a .eh_frame section, zero is used to distinguish CIEs from FDEs. */
if (eh_frame_p)
cie_id = 0;
else if (dwarf64_p)
cie_id = DW64_CIE_ID;
else
cie_id = DW_CIE_ID;
if (dwarf64_p)
{
@ -1124,7 +1134,8 @@ decode_frame_entry (struct comp_unit *unit, char *buf, int eh_frame_p)
cie->encoding = encoding_for_size (unit->addr_size);
/* Check version number. */
gdb_assert (read_1_byte (unit->abfd, buf) == DW_CIE_VERSION);
if (read_1_byte (unit->abfd, buf) != DW_CIE_VERSION)
return NULL;
buf += 1;
/* Interpret the interesting bits of the augmentation. */
@ -1159,6 +1170,8 @@ decode_frame_entry (struct comp_unit *unit, char *buf, int eh_frame_p)
length = read_unsigned_leb128 (unit->abfd, buf, &bytes_read);
buf += bytes_read;
if (buf > end)
return NULL;
cie->initial_instructions = buf + length;
augmentation++;
}
@ -1211,16 +1224,20 @@ decode_frame_entry (struct comp_unit *unit, char *buf, int eh_frame_p)
/* This is a FDE. */
struct dwarf2_fde *fde;
/* In an .eh_frame section, the CIE pointer is the delta between the
address within the FDE where the CIE pointer is stored and the
address of the CIE. Convert it to an offset into the .eh_frame
section. */
if (eh_frame_p)
{
/* In an .eh_frame section, the CIE pointer is the delta
between the address within the FDE where the CIE pointer
is stored and the address of the CIE. Convert it to an
offset into the .eh_frame section. */
cie_pointer = buf - unit->dwarf_frame_buffer - cie_pointer;
cie_pointer -= (dwarf64_p ? 8 : 4);
}
/* In either case, validate the result is still within the section. */
if (cie_pointer >= unit->dwarf_frame_size)
return NULL;
fde = (struct dwarf2_fde *)
obstack_alloc (&unit->objfile->psymbol_obstack,
sizeof (struct dwarf2_fde));
@ -1252,6 +1269,8 @@ decode_frame_entry (struct comp_unit *unit, char *buf, int eh_frame_p)
length = read_unsigned_leb128 (unit->abfd, buf, &bytes_read);
buf += bytes_read + length;
if (buf > end)
return NULL;
}
fde->instructions = buf;
@ -1262,6 +1281,99 @@ decode_frame_entry (struct comp_unit *unit, char *buf, int eh_frame_p)
return end;
}
/* Read a CIE or FDE in BUF and decode it. */
static char *
decode_frame_entry (struct comp_unit *unit, char *start, int eh_frame_p)
{
enum { NONE, ALIGN4, ALIGN8, FAIL } workaround = NONE;
char *ret;
const char *msg;
ptrdiff_t start_offset;
while (1)
{
ret = decode_frame_entry_1 (unit, start, eh_frame_p);
if (ret != NULL)
break;
/* We have corrupt input data of some form. */
/* ??? Try, weakly, to work around compiler/assembler/linker bugs
and mismatches wrt padding and alignment of debug sections. */
/* Note that there is no requirement in the standard for any
alignment at all in the frame unwind sections. Testing for
alignment before trying to interpret data would be incorrect.
However, GCC traditionally arranged for frame sections to be
sized such that the FDE length and CIE fields happen to be
aligned (in theory, for performance). This, unfortunately,
was done with .align directives, which had the side effect of
forcing the section to be aligned by the linker.
This becomes a problem when you have some other producer that
creates frame sections that are not as strictly aligned. That
produces a hole in the frame info that gets filled by the
linker with zeros.
The GCC behaviour is arguably a bug, but it's effectively now
part of the ABI, so we're now stuck with it, at least at the
object file level. A smart linker may decide, in the process
of compressing duplicate CIE information, that it can rewrite
the entire output section without this extra padding. */
start_offset = start - unit->dwarf_frame_buffer;
if (workaround < ALIGN4 && (start_offset & 3) != 0)
{
start += 4 - (start_offset & 3);
workaround = ALIGN4;
continue;
}
if (workaround < ALIGN8 && (start_offset & 7) != 0)
{
start += 8 - (start_offset & 7);
workaround = ALIGN8;
continue;
}
/* Nothing left to try. Arrange to return as if we've consumed
the entire input section. Hopefully we'll get valid info from
the other of .debug_frame/.eh_frame. */
workaround = FAIL;
ret = unit->dwarf_frame_buffer + unit->dwarf_frame_size;
break;
}
switch (workaround)
{
case NONE:
break;
case ALIGN4:
complaint (&symfile_complaints,
"Corrupt data in %s:%s; align 4 workaround apparently succeeded",
unit->dwarf_frame_section->owner->filename,
unit->dwarf_frame_section->name);
break;
case ALIGN8:
complaint (&symfile_complaints,
"Corrupt data in %s:%s; align 8 workaround apparently succeeded",
unit->dwarf_frame_section->owner->filename,
unit->dwarf_frame_section->name);
break;
default:
complaint (&symfile_complaints,
"Corrupt data in %s:%s",
unit->dwarf_frame_section->owner->filename,
unit->dwarf_frame_section->name);
break;
}
return ret;
}
/* FIXME: kettenis/20030504: This still needs to be integrated with
@ -1307,9 +1419,9 @@ dwarf2_build_frame_info (struct objfile *objfile)
unit.dwarf_frame_section = dwarf_eh_frame_section;
/* FIXME: kettenis/20030602: This is the DW_EH_PE_datarel base
that for the i386/amd64 target, which currently is the only
target in GCC that supports/uses the DW_EH_PE_datarel
encoding. */
that for the i386/amd64 target, which currently is the only
target in GCC that supports/uses the DW_EH_PE_datarel
encoding. */
got = bfd_get_section_by_name (unit.abfd, ".got");
if (got)
unit.dbase = got->vma;