[6/9] 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 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.
gas/
* gen-sframe.c: Skip SFrame generation if CFI specifies
non-FP/SP base register.
Reviewed-by: Andreas Krebbel <krebbel@linux.ibm.com>
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
---
Notes (jremus):
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 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
@@ -986,7 +986,11 @@ 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;
@@ -1004,9 +1008,14 @@ 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;