return SFRAME_XLATE_OK;
}
+/* Translate DW_CFA_same_value into SFrame context.
+
+ DW_CFA_same_value op indicates that current value of register is the same as
+ in the previous frame, i.e. no restoration needed. In SFrame stack trace
+ format, the handling is done similar to DW_CFA_restore.
+
+ For SFRAME_CFA_RA_REG, if RA-tracking is enabled, reset the SFrame FRE state
+ for REG_RA to indicate that register does not need restoration. P.S.: Even
+ though resetting just REG_RA may be contradicting the AArch64 ABI (as Frame
+ Record contains for FP and LR), sframe_xlate_do_same_value () does not
+ detect the case and assumes the users' DW_CFA_same_value SFRAME_CFA_RA_REG
+ has a sound reason. For ABIs, where RA-tracking is disabled, handle it
+ similar to DW_CFA_restore: ignore the directive, it is safe to skip. The
+ reasoning is similar to that for DW_CFA_restore: if such a restoration was
+ meant to be of any consequence, there must have been the necessary CFI
+ directives for updating the CFA rule too such that the recovered RA from
+ stack is valid.
+
+ SFrame based stacktracers will implement CFA-based SP recovery for all ABIs:
+ SP for previous frame is based on the applicable CFA-rule. There is no
+ representation in SFrame to indicate "no restoration needed" for REG_SP,
+ when going to the previous frame. That said, if DW_CFA_same_value is seen
+ for SFRAME_CFA_SP_REG, handle it similar to DW_CFA_restore: ignore the
+ directive, it is safe to skip. The reasoning is similar to that for
+ DW_CFA_restore: if such a restoration was meant to be of any consequence,
+ there must have been the necessary CFI directives for updating the CFA rule
+ too. The latter will be duly processed by the SFrame generation code, as
+ expected.
+
+ For SFRAME_CFA_FP_REG, reset the state of the current FRE to indicate that
+ the value is the same as previous frame.
+
+ Return SFRAME_XLATE_OK if success. */
+
+static int
+sframe_xlate_do_same_value (const struct sframe_xlate_ctx *xlate_ctx,
+ const struct cfi_insn_data *cfi_insn)
+{
+ struct sframe_row_entry *cur_fre = xlate_ctx->cur_fre;
+
+ if (sframe_ra_tracking_p () && cfi_insn->u.r == SFRAME_CFA_RA_REG)
+ {
+ cur_fre->ra_loc = SFRAME_FRE_ELEM_LOC_REG;
+ cur_fre->ra_offset = 0;
+ cur_fre->merge_candidate = false;
+ }
+ else if (cfi_insn->u.r == SFRAME_CFA_FP_REG)
+ {
+ cur_fre->bp_loc = SFRAME_FRE_ELEM_LOC_REG;
+ cur_fre->bp_offset = 0;
+ cur_fre->merge_candidate = false;
+ }
+
+ /* Safe to skip. */
+ return SFRAME_XLATE_OK;
+}
+
/* Returns the DWARF call frame instruction name or fake CFI name for the
specified CFI opcode, or NULL if the value is not recognized. */
case CFI_escape:
err = sframe_xlate_do_cfi_escape (xlate_ctx, cfi_insn);
break;
- /* Following CFI opcodes are not processed at this time.
- These do not impact the coverage of the basic stack tracing
- information as conveyed in the SFrame format. */
case DW_CFA_undefined:
err = sframe_xlate_do_cfi_undefined (xlate_ctx, cfi_insn);
break;
case DW_CFA_same_value:
+ err = sframe_xlate_do_same_value (xlate_ctx, cfi_insn);
break;
default:
/* Other skipped operations may, however, impact the asynchronicity. */
projects / thirdparty / binutils-gdb.git / commitdiff
