* builtins.c (expand_builtin) <BUILT_IN_DWARF_FP_REGNUM>: Remove.

        <BUILT_IN_DWARF_SP_COLUMN>: New.
        * builtins.def (BUILT_IN_DWARF_FP_REGNUM): Remove.
        (BUILT_IN_DWARF_SP_COLUMN): New.
        * dwarf2out.c (expand_builtin_dwarf_fp_regnum): Remove.
        (expand_builtin_dwarf_sp_column): New.
        * except.h: Update to match.
        * unwind-dw2.c (execute_stack_op): Correct stack push typo.
        (execute_cfa_program): Record location expression address
        before extracting length.
        (uw_update_context_1): Install old CFA into stack pointer column.
        (uw_init_context_1): Set cfa_reg to stack pointer column.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@66447 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 27 insertions, 19 deletions

diff --git a/gcc/unwind-dw2.c b/gcc/unwind-dw2.c
index 6ffda3f7ead..7596ef07c9c 100644
--- a/gcc/unwind-dw2.c
+++ b/gcc/unwind-dw2.c
@@ -726,7 +726,7 @@ execute_stack_op (const unsigned char *op_ptr, const unsigned char *op_end,
       /* Most things push a result value.  */
       if ((size_t) stack_elt >= sizeof(stack)/sizeof(*stack))
 	abort ();
-      stack[++stack_elt] = result;
+      stack[stack_elt++] = result;
     no_push:;
     }
 
@@ -878,17 +878,17 @@ execute_cfa_program (const unsigned char *insn_ptr,
 	  break;
 
 	case DW_CFA_def_cfa_expression:
-	  insn_ptr = read_uleb128 (insn_ptr, &utmp);
 	  fs->cfa_exp = insn_ptr;
 	  fs->cfa_how = CFA_EXP;
+	  insn_ptr = read_uleb128 (insn_ptr, &utmp);
 	  insn_ptr += utmp;
 	  break;
 
 	case DW_CFA_expression:
 	  insn_ptr = read_uleb128 (insn_ptr, &reg);
-	  insn_ptr = read_uleb128 (insn_ptr, &utmp);
 	  fs->regs.reg[DWARF_REG_TO_UNWIND_COLUMN (reg)].how = REG_SAVED_EXP;
 	  fs->regs.reg[DWARF_REG_TO_UNWIND_COLUMN (reg)].loc.exp = insn_ptr;
+	  insn_ptr = read_uleb128 (insn_ptr, &utmp);
 	  insn_ptr += utmp;
 	  break;
 
@@ -1076,37 +1076,41 @@ static void
 uw_update_context_1 (struct _Unwind_Context *context, _Unwind_FrameState *fs)
 {
   struct _Unwind_Context orig_context = *context;
+  _Unwind_Word tmp_sp;
   void *cfa;
   long i;
 
+  /* Special handling here: Many machines do not use a frame pointer,
+     and track the CFA only through offsets from the stack pointer from
+     one frame to the next.  In this case, the stack pointer is never
+     stored, so it has no saved address in the context.  What we do
+     have is the CFA from the previous stack frame.
+
+     In very special situations (such as unwind info for signal return),
+     there may be location expressions that use the stack pointer as well.
+
+     Given that other unwind mechanisms generally won't work if you try
+     to represent stack pointer saves and restores directly, we don't
+     bother conditionalizing this at all.  */
+  tmp_sp = (_Unwind_Ptr) context->cfa;
+  _Unwind_SetGRPtr (&orig_context, __builtin_dwarf_sp_column (), &tmp_sp);
+
   /* Compute this frame's CFA.  */
   switch (fs->cfa_how)
     {
     case CFA_REG_OFFSET:
-      /* Special handling here: Many machines do not use a frame pointer,
-	 and track the CFA only through offsets from the stack pointer from
-	 one frame to the next.  In this case, the stack pointer is never
-	 stored, so it has no saved address in the context.  What we do
-	 have is the CFA from the previous stack frame.  */
-      if (_Unwind_GetGRPtr (context, fs->cfa_reg) == NULL)
-	cfa = context->cfa;
-      else
-	cfa = (void *) (_Unwind_Ptr) _Unwind_GetGR (context, fs->cfa_reg);
+      cfa = (void *) (_Unwind_Ptr) _Unwind_GetGR (&orig_context, fs->cfa_reg);
       cfa += fs->cfa_offset;
       break;
 
     case CFA_EXP:
-      /* ??? No way of knowing what register number is the stack pointer
-	 to do the same sort of handling as above.  Assume that if the
-	 CFA calculation is so complicated as to require a stack program
-	 that this will not be a problem.  */
       {
 	const unsigned char *exp = fs->cfa_exp;
 	_Unwind_Word len;
 
 	exp = read_uleb128 (exp, &len);
 	cfa = (void *) (_Unwind_Ptr)
-	  execute_stack_op (exp, exp + len, context, 0);
+	  execute_stack_op (exp, exp + len, &orig_context, 0);
 	break;
       }
 
@@ -1121,14 +1125,18 @@ uw_update_context_1 (struct _Unwind_Context *context, _Unwind_FrameState *fs)
       {
       case REG_UNSAVED:
 	break;
+
       case REG_SAVED_OFFSET:
-	_Unwind_SetGRPtr (context, i, (void *) (cfa + fs->regs.reg[i].loc.offset));
+	_Unwind_SetGRPtr (context, i,
+			  (void *) (cfa + fs->regs.reg[i].loc.offset));
 	break;
+
       case REG_SAVED_REG:
 	_Unwind_SetGRPtr
 	  (context, i,
 	   _Unwind_GetGRPtr (&orig_context, fs->regs.reg[i].loc.reg));
 	break;
+
       case REG_SAVED_EXP:
 	{
 	  const unsigned char *exp = fs->regs.reg[i].loc.exp;
@@ -1190,7 +1198,7 @@ uw_init_context_1 (struct _Unwind_Context *context,
   /* Force the frame state to use the known cfa value.  */
   context->cfa = outer_cfa;
   fs.cfa_how = CFA_REG_OFFSET;
-  fs.cfa_reg = 0;
+  fs.cfa_reg = __builtin_dwarf_sp_column ();
   fs.cfa_offset = 0;
 
   uw_update_context_1 (context, &fs);