[v4,06/15] gas: Skip SFrame FDE if CFI specifies non-FP/SP base register
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Commit Message
Do not generate SFrame FDE if DWARF CFI directives .cfi_def_cfa or
.cfi_def_cfa_register specify a CFA base register number other than
the architecture-specific stack-pointer (SP) or frame-pointer (FP)
register numbers.
This also causes the assembler to print a warning message, so that
skipping of the SFrame FDE does not occur silently.
Update the generic ld SFrame test case to be architecture independent.
Do not use CFI directive .cfi_def_cfa, as the specified CFA base
register number is not a valid SP/FP register number on all
architectures. An invalid SP/FP register number will now cause the
assembler to print a warning message and skip SFrame FDE generation.
Remove the offending CFI directive, that cannot be coded architecture-
independent, as the test case requires SFrame information to be
generated. This was reported by the Linaro-TCWG-CI for AArch64.
gas/
* gen-sframe.c: Skip SFrame generation if CFI specifies
non-FP/SP base register.
ld/testsuite/
* ld-sframe/discard.s: Update generic SFrame test case to be
architecture independent.
Reviewed-by: Andreas Krebbel <krebbel@linux.ibm.com>
Reviewed-by: Indu Bhagat <indu.bhagat@oracle.com>
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
---
Notes (jremus):
Changes v2 -> v3:
- Corrected formatting of ChangeLog in commit message.
Changes v1 -> v2:
- Update generic SFrame test case to be architecture independent to
resolve generic ld SFrame test case failure reported by
Linaro-TCWG-CI for AArch64. It would fail similar on s390x.
Without this patch the assembler would erroneously generate bad SFrame
information for the s390-specific SFrame error test cases 1 and 2, that
get introduced by patch "s390: Initial support to generate .sframe from
CFI directives in assembler".
gas/gen-sframe.c | 13 +++++++++++--
ld/testsuite/ld-sframe/discard.s | 1 -
2 files changed, 11 insertions(+), 3 deletions(-)
@@ -988,7 +988,11 @@ sframe_xlate_do_def_cfa (struct sframe_xlate_ctx *xlate_ctx,
get_dw_fde_start_addrS (xlate_ctx->dw_fde));
}
/* Define the current CFA rule to use the provided register and
- offset. */
+ offset. However, if the register is not FP/SP, skip creating
+ SFrame stack trace info for the function. */
+ if (cfi_insn->u.r != SFRAME_CFA_SP_REG
+ && cfi_insn->u.r != SFRAME_CFA_FP_REG)
+ return SFRAME_XLATE_ERR_NOTREPRESENTED; /* Not represented. */
sframe_fre_set_cfa_base_reg (cur_fre, cfi_insn->u.ri.reg);
sframe_fre_set_cfa_offset (cur_fre, cfi_insn->u.ri.offset);
cur_fre->merge_candidate = false;
@@ -1006,9 +1010,14 @@ sframe_xlate_do_def_cfa_register (struct sframe_xlate_ctx *xlate_ctx,
struct sframe_row_entry *last_fre = xlate_ctx->last_fre;
/* Get the scratchpad FRE. This FRE will eventually get linked in. */
struct sframe_row_entry *cur_fre = xlate_ctx->cur_fre;
+
gas_assert (cur_fre);
/* Define the current CFA rule to use the provided register (but to
- keep the old offset). */
+ keep the old offset). However, if the register is not FP/SP,
+ skip creating SFrame stack trace info for the function. */
+ if (cfi_insn->u.r != SFRAME_CFA_SP_REG
+ && cfi_insn->u.r != SFRAME_CFA_FP_REG)
+ return SFRAME_XLATE_ERR_NOTREPRESENTED; /* Not represented. */
sframe_fre_set_cfa_base_reg (cur_fre, cfi_insn->u.ri.reg);
sframe_fre_set_cfa_offset (cur_fre, last_fre->cfa_offset);
cur_fre->merge_candidate = false;
@@ -5,7 +5,6 @@
foo:
.cfi_startproc
.cfi_def_cfa_offset 16
- .cfi_def_cfa 7, 8
.cfi_endproc
.globl _start