Files
binutils-gdb/libsframe/sframe-dump.c
Jens Remus 5079bf8959 gas: sframe: Represent .cfi_undefined RA as FRE without offsets
In DWARF CFI an "undefined" register rule for the return address (RA)
register indicates that there is no return address and the stack trace
is complete.

Represent DW_CFA_undefined as SFrame FRE without any offsets, so that a
stack tracer implementation can use this as indication that an outermost
frame has been reached and the stack trace is complete.

This representation is backward compatible, as existing stack tracers
should already deal with the case, that an SFrame FRE a so far invalid
offset count of zero and stop the trace.

include/
	* sframe.h (SFRAME_V2_FRE_RA_UNDEFINED_P): New macro to test
	FRE info word for RA undefined (FRE without any offsets).

binutils/
	* NEWS: Mention SFrame can represent an undefined RA as FRE
	without	any offsets.

gas/
	* gen-sframe.h (struct sframe_row_entry): Add ra_undefined_p
	flag.
	* gen-sframe.c (sframe_row_entry_new): Initialize ra_undefined_p
	flag to not set.
	(sframe_row_entry_initialize): Treat ra_undefined_p flag as
	sticky.
	(sframe_fre_set_ra_track): Reset ra_undefined_p flag.
	(sframe_xlate_do_restore): Reset ra_undefined_p flag to saved
	state.
	(sframe_xlate_do_same_value): Reset ra_undefined_p flag.
	(sframe_xlate_do_cfi_undefined): For RA set ra_undefined_p flag.
	(output_sframe_row_entry): Represent RA undefined as SFrame FRE
	without any offsets and FRE info word fields zeroed.
	* NEWS: Mention assembler represents .cfi_undefined RA in SFrame
	as FRE without any offsets.

libsframe/
	* doc/sframe-spec.texi (Changes from Version 1 to Version 2):
	Mention that a SFrame FRE without any offsets flag indicates an
	outermost frame with an undefined RA.
	(fre_offset_count): Document that a FRE offset count of zero
	indicates an outermost frame with an undefined RA.
	* sframe.c (sframe_get_fre_ra_undefined_p): Use macro
	SFRAME_V2_FRE_RA_UNDEFINED_P.
	(sframe_fre_get_fp_offset, sframe_fre_get_ra_offset): Do not
	return fixed FP/RA offset if RA undefined.
	* sframe-dump.c (dump_sframe_func_with_fres): Show FRE without
	any offsets as "RA undefined".

gas/testsuite/
	* gas/cfi-sframe/cfi-sframe.exp: Run tests for .cfi_undefined RA
	on AArch64, s390x, and x86-64.
	* gas/cfi-sframe/cfi-sframe-aarch64-ra-undefined-1.d: Add test
	for .cfi_undefined RA on AArch64.
	* gas/cfi-sframe/cfi-sframe-aarch64-ra-undefined-1.s: Likewise.
	* as/cfi-sframe/cfi-sframe-s390x-ra-undefined-1.d: Add test
	for .cfi_undefined RA on s390x.
	* gas/cfi-sframe/cfi-sframe-s390x-ra-undefined-1.s: Likewise.
	* gas/cfi-sframe/cfi-sframe-x86_64-ra-undefined-1.d: Add test
	for .cfi_undefined RA on x86-64.
	* gas/cfi-sframe/cfi-sframe-x86_64-ra-undefined-1.s: Likewise.

Signed-off-by: Jens Remus <jremus@linux.ibm.com>
2025-10-15 17:45:48 +02:00

281 lines
8.3 KiB
C

/* sframe-dump.c - Textual dump of .sframe.
Copyright (C) 2022-2025 Free Software Foundation, Inc.
This file is part of libsframe.
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 <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <inttypes.h>
#include "sframe-impl.h"
/* Return TRUE if the SFrame section is associated with the aarch64 ABIs. */
static bool
is_sframe_abi_arch_aarch64 (sframe_decoder_ctx *sfd_ctx)
{
bool aarch64_p = false;
uint8_t abi_arch = sframe_decoder_get_abi_arch (sfd_ctx);
if (abi_arch == SFRAME_ABI_AARCH64_ENDIAN_BIG
|| abi_arch == SFRAME_ABI_AARCH64_ENDIAN_LITTLE)
aarch64_p = true;
return aarch64_p;
}
/* Return TRUE if the SFrame section is associated with the s390x ABI. */
static bool
is_sframe_abi_arch_s390x (sframe_decoder_ctx *sfd_ctx)
{
return sframe_decoder_get_abi_arch (sfd_ctx) == SFRAME_ABI_S390X_ENDIAN_BIG;
}
static void
dump_sframe_header_flags (sframe_decoder_ctx *sfd_ctx)
{
uint8_t flags;
const char *prefix = "Flags: ";
flags = sframe_decoder_get_flags (sfd_ctx);
if (!flags)
{
printf ("%11sNONE\n", prefix);
return;
}
#define PRINT_FLAG(x) \
if (flags & (x)) \
{ flags = (flags & ~(x)); \
printf ("%11s%s%s\n", prefix, #x, flags ? "," : ""); \
prefix = " "; \
}
PRINT_FLAG (SFRAME_F_FDE_SORTED);
PRINT_FLAG (SFRAME_F_FRAME_POINTER);
PRINT_FLAG (SFRAME_F_FDE_FUNC_START_PCREL);
#undef PRINT_FLAG
/* Print any residual flags, should this implementation be out of sync when
new flags are added. */
if (flags)
printf ("%11s%d\n", prefix, flags);
}
static void
dump_sframe_header (sframe_decoder_ctx *sfd_ctx)
{
uint8_t ver;
const char *ver_str = NULL;
int8_t cfa_fixed_fp_offset;
int8_t cfa_fixed_ra_offset;
const sframe_header *header = &(sfd_ctx->sfd_header);
/* Prepare SFrame section version string. */
const char *version_names[]
= { "NULL",
"SFRAME_VERSION_1",
"SFRAME_VERSION_2" };
ver = sframe_decoder_get_version (sfd_ctx);
if (ver <= SFRAME_VERSION)
ver_str = version_names[ver];
/* CFA fixed FP and RA offsets. */
cfa_fixed_fp_offset = header->sfh_cfa_fixed_fp_offset;
cfa_fixed_ra_offset = header->sfh_cfa_fixed_ra_offset;
const char* subsec_name = "Header";
printf ("\n");
printf (" %s :\n", subsec_name);
printf ("\n");
printf (" Version: %s\n", ver_str);
dump_sframe_header_flags (sfd_ctx);
if (cfa_fixed_fp_offset != SFRAME_CFA_FIXED_FP_INVALID)
printf (" CFA fixed FP offset: %d\n", cfa_fixed_fp_offset);
if (cfa_fixed_ra_offset != SFRAME_CFA_FIXED_RA_INVALID)
printf (" CFA fixed RA offset: %d\n", cfa_fixed_ra_offset);
printf (" Num FDEs: %d\n", sframe_decoder_get_num_fidx (sfd_ctx));
printf (" Num FREs: %d\n", header->sfh_num_fres);
}
static void
dump_sframe_func_with_fres (sframe_decoder_ctx *sfd_ctx,
unsigned int funcidx,
uint64_t sec_addr)
{
uint32_t j = 0;
uint32_t num_fres = 0;
uint32_t func_size = 0;
int32_t func_start_address = 0;
unsigned char func_info = 0;
uint64_t func_start_pc_vma = 0;
uint64_t fre_start_pc_vma = 0;
const char *base_reg_str[] = {"fp", "sp"};
bool ra_undefined_p = false;
int32_t cfa_offset = 0;
int32_t fp_offset = 0;
int32_t ra_offset = 0;
uint8_t base_reg_id = 0;
int err[3] = {0, 0, 0};
sframe_frame_row_entry fre;
/* Get the SFrame function descriptor. */
sframe_decoder_get_funcdesc (sfd_ctx, funcidx, &num_fres,
&func_size, &func_start_address, &func_info);
/* Calculate the virtual memory address for function start pc. Some older
SFrame V2 sections in ET_DYN or ET_EXEC may still have the
SFRAME_F_FDE_FUNC_START_PCREL flag unset, and hence may be using the
old encoding. Continue to support dumping the sections at least. */
func_start_pc_vma = func_start_address + sec_addr;
if (sframe_decoder_get_flags (sfd_ctx) & SFRAME_F_FDE_FUNC_START_PCREL)
func_start_pc_vma += sframe_decoder_get_offsetof_fde_start_addr (sfd_ctx,
funcidx,
NULL);
/* Mark FDEs with [m] where the FRE start address is interpreted as a
mask. */
int fde_type_addrmask_p = (SFRAME_V1_FUNC_FDE_TYPE (func_info)
== SFRAME_FDE_TYPE_PCMASK);
const char *fde_type_marker
= (fde_type_addrmask_p ? "[m]" : " ");
printf ("\n func idx [%d]: pc = 0x%"PRIx64 ", size = %d bytes",
funcidx,
func_start_pc_vma,
func_size);
if (is_sframe_abi_arch_aarch64 (sfd_ctx)
&& (SFRAME_V1_FUNC_PAUTH_KEY (func_info) == SFRAME_AARCH64_PAUTH_KEY_B))
printf (", pauth = B key");
char temp[100];
printf ("\n %-7s%-8s %-10s%-10s%-13s",
"STARTPC", fde_type_marker, "CFA", "FP", "RA");
for (j = 0; j < num_fres; j++)
{
sframe_decoder_get_fre (sfd_ctx, funcidx, j, &fre);
fre_start_pc_vma = (fde_type_addrmask_p
? fre.fre_start_addr
: func_start_pc_vma + fre.fre_start_addr);
/* FIXME - fixup the err caching in array.
assert no error for base reg id and RA undefined. */
base_reg_id = sframe_fre_get_base_reg_id (&fre, &err[0]);
ra_undefined_p = sframe_fre_get_ra_undefined_p (sfd_ctx, &fre, &err[0]);
cfa_offset = sframe_fre_get_cfa_offset (sfd_ctx, &fre, &err[0]);
fp_offset = sframe_fre_get_fp_offset (sfd_ctx, &fre, &err[1]);
ra_offset = sframe_fre_get_ra_offset (sfd_ctx, &fre, &err[2]);
/* Dump VMA. */
printf ("\n");
printf (" %016"PRIx64, fre_start_pc_vma);
/* Dump RA undefined (FRE without any offsets). */
if (ra_undefined_p)
{
printf (" RA undefined");
continue;
}
/* Dump CFA info. */
sprintf (temp, "%s+%d", base_reg_str[base_reg_id], cfa_offset);
printf (" %-10s", temp);
/* Dump SP/FP info. */
if (err[1] == 0)
{
if (is_sframe_abi_arch_s390x (sfd_ctx)
&& SFRAME_V2_S390X_OFFSET_IS_REGNUM (fp_offset))
sprintf (temp, "r%d", SFRAME_V2_S390X_OFFSET_DECODE_REGNUM (fp_offset));
else
sprintf (temp, "c%+d", fp_offset);
}
else
strcpy (temp, "u");
printf ("%-10s", temp);
/* Dump RA info.
If an ABI does not track RA offset, e.g., AMD64, display 'f',
else display the offset d as 'c+-d'. */
if (sframe_decoder_get_fixed_ra_offset (sfd_ctx)
!= SFRAME_CFA_FIXED_RA_INVALID)
strcpy (temp, "f");
/* If an ABI does track RA offset, e.g. s390x, it can be a padding
to represent FP without RA being saved on stack. */
else if (err[2] == 0 && ra_offset == SFRAME_FRE_RA_OFFSET_INVALID)
sprintf (temp, "U");
else if (err[2] == 0)
{
if (is_sframe_abi_arch_s390x (sfd_ctx)
&& SFRAME_V2_S390X_OFFSET_IS_REGNUM (ra_offset))
sprintf (temp, "r%d", SFRAME_V2_S390X_OFFSET_DECODE_REGNUM (ra_offset));
else
sprintf (temp, "c%+d", ra_offset);
}
else
strcpy (temp, "u");
/* Mark SFrame FRE's RA information with "[s]" if the RA is mangled
with signature bits. */
const char *ra_mangled_p_str
= ((sframe_fre_get_ra_mangled_p (sfd_ctx, &fre, &err[2]))
? "[s]" : " ");
strcat (temp, ra_mangled_p_str);
printf ("%-13s", temp);
}
}
static void
dump_sframe_functions (sframe_decoder_ctx *sfd_ctx, uint64_t sec_addr)
{
uint32_t i;
uint32_t num_fdes;
const char* subsec_name = "Function Index";
printf ("\n %s :\n", subsec_name);
num_fdes = sframe_decoder_get_num_fidx (sfd_ctx);
for (i = 0; i < num_fdes; i++)
{
dump_sframe_func_with_fres (sfd_ctx, i, sec_addr);
printf ("\n");
}
}
void
dump_sframe (sframe_decoder_ctx *sfd_ctx, uint64_t sec_addr)
{
uint8_t ver;
dump_sframe_header (sfd_ctx);
ver = sframe_decoder_get_version (sfd_ctx);
if (ver == SFRAME_VERSION)
dump_sframe_functions (sfd_ctx, sec_addr);
else
printf ("\n No further information can be displayed. %s",
"SFrame version not supported\n");
}