gas: sframe: fix handling of .cfi_def_cfa_register

Fix PR gas/32879 sframe: Assembler internal error when translating
cfi_def_cfa_register

As per the documentation, .cfi_def_cfa_register modifies a rule for
computing CFA; the register is updated, but the offset remains the same.

While translating .cfi_def_cfa_register into SFrame context, we use the
information from last translated FRE to set the CFA offset. However,
there may be cases when the last translated FRE is empty.  Use last FRE
only if available.

Signed-off-by: Claudiu Zissulescu <claudiu.zissulescu-ianculescu@oracle.com>
Signed-off-by: Indu Bhagat <indu.bhagat@oracle.com>

diff --git a/gas/gen-sframe.c b/gas/gen-sframe.c
index 5b5e7b14b3ab1af8161856a833958dae24eed525..5c8c7ebb175f1c6dfec388042f55e0200078d128 100644 (file)
--- a/gas/gen-sframe.c
+++ b/gas/gen-sframe.c
@@ -1038,7 +1038,9 @@ sframe_xlate_do_def_cfa_register (struct sframe_xlate_ctx *xlate_ctx,
       return SFRAME_XLATE_ERR_NOTREPRESENTED; /* Not represented.  */
     }
   sframe_fre_set_cfa_base_reg (cur_fre, cfi_insn->u.r);
-  sframe_fre_set_cfa_offset (cur_fre, last_fre->cfa_offset);
+  if (last_fre)
+    sframe_fre_set_cfa_offset (cur_fre, last_fre->cfa_offset);
+
   cur_fre->merge_candidate = false;
 
   return SFRAME_XLATE_OK;

diff --git a/gas/testsuite/gas/cfi-sframe/cfi-sframe-x86_64-2.d b/gas/testsuite/gas/cfi-sframe/cfi-sframe-x86_64-2.d
new file mode 100644 (file)
index 0000000..d779b6d
--- /dev/null
+++ b/gas/testsuite/gas/cfi-sframe/cfi-sframe-x86_64-2.d
@@ -0,0 +1,21 @@
+#as: --gsframe
+#objdump: --sframe=.sframe
+#name: Check .cfi_def_cfa_register with no previous offset
+#...
+Contents of the SFrame section .sframe:
+
+  Header :
+
+    Version: SFRAME_VERSION_2
+    Flags: NONE
+#?    CFA fixed FP offset: \-?\d+
+#?    CFA fixed RA offset: \-?\d+
+    Num FDEs: 1
+    Num FREs: 1
+
+  Function Index :
+
+    func idx \[0\]: pc = 0x0, size = 0 bytes
+    STARTPC +CFA +FP +RA +
+    0+0000 +fp\+8 +u +f +
+#pass

diff --git a/gas/testsuite/gas/cfi-sframe/cfi-sframe-x86_64-2.s b/gas/testsuite/gas/cfi-sframe/cfi-sframe-x86_64-2.s
new file mode 100644 (file)
index 0000000..f3f9859
--- /dev/null
+++ b/gas/testsuite/gas/cfi-sframe/cfi-sframe-x86_64-2.s
@@ -0,0 +1,4 @@
+# Although not a useful construct by itself, ensure graceful handling.
+       .cfi_startproc
+       .cfi_def_cfa_register 6
+       .cfi_endproc

diff --git a/gas/testsuite/gas/cfi-sframe/cfi-sframe.exp b/gas/testsuite/gas/cfi-sframe/cfi-sframe.exp
index a09946635c20e41cc91e28774325503a80faaa40..b353e27ce56a94273e402526e2821acbe982c5d2 100644 (file)
--- a/gas/testsuite/gas/cfi-sframe/cfi-sframe.exp
+++ b/gas/testsuite/gas/cfi-sframe/cfi-sframe.exp
@@ -90,6 +90,7 @@ if { [istarget "x86_64-*-*"] && [gas_sframe_check] } then {
     if { [gas_x86_64_check] } then {
        set ASFLAGS "$ASFLAGS --64"
        run_dump_test "cfi-sframe-x86_64-1"
+       run_dump_test "cfi-sframe-x86_64-2"
        run_dump_test "cfi-sframe-x86_64-empty-1"
        run_dump_test "cfi-sframe-x86_64-empty-2"
        run_dump_test "cfi-sframe-x86_64-empty-3"