[PATCH v3 11/15] gas: Skip SFrame FDE if .cfi_window_save

[Jens Remus]

CFI opcode DW_CFA_AARCH64_negate_ra_state is multiplexed with
DW_CFA_GNU_window_save. Process DW_CFA_AARCH64_negate_ra_state on
AArch64. Skip generation of SFrame FDE otherwise.

gas/
	* gen-sframe.c: Skip SFrame FDE if .cfi_window_save.

Signed-off-by: Jens Remus <jremus@linux.ibm.com>
---

Notes (jremus):
    Changes v2 -> v3:
    - New patch. The intention is to skip all "unknown" CFI opcodes,
      which SFrame does not explicitly handle. DW_CFA_GNU_window_save
      seems to be handled only for the AArch64-specific multiplexed
      DW_CFA_AARCH64_negate_ra_state. The logic could be changed to be
      dependent on TC_AARCH64 at build-time instead of
      sframe_get_abi_arch() at run-time.

 gas/gen-sframe.c | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/gas/gen-sframe.c b/gas/gen-sframe.c
index 87be3eb05ad2..98166de8cc01 100644
--- a/gas/gen-sframe.c
+++ b/gas/gen-sframe.c
@@ -1257,12 +1257,12 @@ sframe_xlate_do_restore (struct sframe_xlate_ctx *xlate_ctx,
   return SFRAME_XLATE_OK;
 }
 
-/* Translate DW_CFA_GNU_window_save into SFrame context.
+/* Translate DW_CFA_AARCH64_negate_ra_state into SFrame context.
    Return SFRAME_XLATE_OK if success.  */
 
 static int
-sframe_xlate_do_gnu_window_save (struct sframe_xlate_ctx *xlate_ctx,
-				 struct cfi_insn_data *cfi_insn ATTRIBUTE_UNUSED)
+sframe_xlate_do_aarch64_negate_ra_state (struct sframe_xlate_ctx *xlate_ctx,
+					 struct cfi_insn_data *cfi_insn ATTRIBUTE_UNUSED)
 {
   struct sframe_row_entry *cur_fre = xlate_ctx->cur_fre;
 
@@ -1274,6 +1274,25 @@ sframe_xlate_do_gnu_window_save (struct sframe_xlate_ctx *xlate_ctx,
   return SFRAME_XLATE_OK;
 }
 
+/* Translate DW_CFA_GNU_window_save into SFrame context.
+   DW_CFA_AARCH64_negate_ra_state is multiplexed with DW_CFA_GNU_window_save.
+   Return SFRAME_XLATE_OK if success.  */
+
+static int
+sframe_xlate_do_gnu_window_save (struct sframe_xlate_ctx *xlate_ctx,
+				 struct cfi_insn_data *cfi_insn)
+{
+  unsigned char abi_arch = sframe_get_abi_arch ();
+
+  /* Translate DW_CFA_AARCH64_negate_ra_state into SFrame context.  */
+  if (abi_arch == SFRAME_ABI_AARCH64_ENDIAN_BIG
+      || abi_arch == SFRAME_ABI_AARCH64_ENDIAN_LITTLE)
+    return sframe_xlate_do_aarch64_negate_ra_state (xlate_ctx, cfi_insn);
+
+  as_warn (_("skipping SFrame FDE due to .cfi_window_save"));
+  return SFRAME_XLATE_ERR_NOTREPRESENTED;  /* Not represented.  */
+}
+
 /* Returns the DWARF call frame instruction name or fake CFI name for the
    specified CFI opcode, or NULL if the value is not recognized.  */
 
-- 
2.40.1