[rfc][patch] Fix for gdb/10275 (mis-handling of DW_CFA_restore_state)

[ppluzhnikov at google dot com (Paul Pluzhnikov)]

Greetings,

Fixing this looks easier than I expected :-)

Regtested on Linux/x86_64 (no regressions).

I also verified that I get correct stack for my reduced test case in
gdb/10275, and in my real gcc-4.5 compiled optimized code.

If this looks correct, I'll add a test case.

Thanks,
--
Paul Pluzhnikov

2009-06-12  Paul Pluzhnikov  <ppluzhnikov@google.com>

	gdb/10275
	* dwarf2-frame.c (dwarf2_frame_state): Move cfa_offset, cfa_reg,
	cfa_how and cfa_exp into regs and adjust users.

Index: dwarf2-frame.c
===================================================================
RCS file: /cvs/src/src/gdb/dwarf2-frame.c,v
retrieving revision 1.87
diff -u -p -u -r1.87 dwarf2-frame.c
--- dwarf2-frame.c	3 Jan 2009 05:57:51 -0000	1.87
+++ dwarf2-frame.c	13 Jun 2009 01:20:54 -0000
@@ -164,19 +164,19 @@ struct dwarf2_frame_state
     struct dwarf2_frame_state_reg *reg;
     int num_regs;
 
+    LONGEST cfa_offset;
+    ULONGEST cfa_reg;
+    enum {
+      CFA_UNSET,
+      CFA_REG_OFFSET,
+      CFA_EXP
+    } cfa_how;
+    gdb_byte *cfa_exp;
+
     /* Used to implement DW_CFA_remember_state.  */
     struct dwarf2_frame_state_reg_info *prev;
   } regs;
 
-  LONGEST cfa_offset;
-  ULONGEST cfa_reg;
-  gdb_byte *cfa_exp;
-  enum {
-    CFA_UNSET,
-    CFA_REG_OFFSET,
-    CFA_EXP
-  } cfa_how;
-
   /* The PC described by the current frame state.  */
   CORE_ADDR pc;
 
@@ -502,21 +502,21 @@ bad CFI data; mismatched DW_CFA_restore_
 	      break;
 
 	    case DW_CFA_def_cfa:
-	      insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_reg);
+	      insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->regs.cfa_reg);
 	      insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
 
 	      if (fs->armcc_cfa_offsets_sf)
 		utmp *= fs->data_align;
 
-	      fs->cfa_offset = utmp;
-	      fs->cfa_how = CFA_REG_OFFSET;
+	      fs->regs.cfa_offset = utmp;
+	      fs->regs.cfa_how = CFA_REG_OFFSET;
 	      break;
 
 	    case DW_CFA_def_cfa_register:
-	      insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_reg);
-	      fs->cfa_reg = dwarf2_frame_adjust_regnum (gdbarch, fs->cfa_reg,
-							eh_frame_p);
-	      fs->cfa_how = CFA_REG_OFFSET;
+	      insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->regs.cfa_reg);
+	      fs->regs.cfa_reg = dwarf2_frame_adjust_regnum (gdbarch, fs->regs.cfa_reg,
+                                                             eh_frame_p);
+	      fs->regs.cfa_how = CFA_REG_OFFSET;
 	      break;
 
 	    case DW_CFA_def_cfa_offset:
@@ -525,7 +525,7 @@ bad CFI data; mismatched DW_CFA_restore_
 	      if (fs->armcc_cfa_offsets_sf)
 		utmp *= fs->data_align;
 
-	      fs->cfa_offset = utmp;
+	      fs->regs.cfa_offset = utmp;
 	      /* cfa_how deliberately not set.  */
 	      break;
 
@@ -533,10 +533,10 @@ bad CFI data; mismatched DW_CFA_restore_
 	      break;
 
 	    case DW_CFA_def_cfa_expression:
-	      insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_exp_len);
-	      fs->cfa_exp = insn_ptr;
-	      fs->cfa_how = CFA_EXP;
-	      insn_ptr += fs->cfa_exp_len;
+	      insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->regs.cfa_exp_len);
+	      fs->regs.cfa_exp = insn_ptr;
+	      fs->regs.cfa_how = CFA_EXP;
+	      insn_ptr += fs->regs.cfa_exp_len;
 	      break;
 
 	    case DW_CFA_expression:
@@ -589,17 +589,18 @@ bad CFI data; mismatched DW_CFA_restore_
 	      break;
 
 	    case DW_CFA_def_cfa_sf:
-	      insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_reg);
-	      fs->cfa_reg = dwarf2_frame_adjust_regnum (gdbarch, fs->cfa_reg,
-							eh_frame_p);
+	      insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->regs.cfa_reg);
+	      fs->regs.cfa_reg = dwarf2_frame_adjust_regnum (gdbarch,
+                                                             fs->regs.cfa_reg,
+                                                             eh_frame_p);
 	      insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset);
-	      fs->cfa_offset = offset * fs->data_align;
-	      fs->cfa_how = CFA_REG_OFFSET;
+	      fs->regs.cfa_offset = offset * fs->data_align;
+	      fs->regs.cfa_how = CFA_REG_OFFSET;
 	      break;
 
 	    case DW_CFA_def_cfa_offset_sf:
 	      insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset);
-	      fs->cfa_offset = offset * fs->data_align;
+	      fs->regs.cfa_offset = offset * fs->data_align;
 	      /* cfa_how deliberately not set.  */
 	      break;
 
@@ -932,19 +933,19 @@ dwarf2_frame_cache (struct frame_info *t
   execute_cfa_program (fde, fde->instructions, fde->end, this_frame, fs);
 
   /* Calculate the CFA.  */
-  switch (fs->cfa_how)
+  switch (fs->regs.cfa_how)
     {
     case CFA_REG_OFFSET:
-      cache->cfa = read_reg (this_frame, fs->cfa_reg);
+      cache->cfa = read_reg (this_frame, fs->regs.cfa_reg);
       if (fs->armcc_cfa_offsets_reversed)
-	cache->cfa -= fs->cfa_offset;
+	cache->cfa -= fs->regs.cfa_offset;
       else
-	cache->cfa += fs->cfa_offset;
+	cache->cfa += fs->regs.cfa_offset;
       break;
 
     case CFA_EXP:
       cache->cfa =
-	execute_stack_op (fs->cfa_exp, fs->cfa_exp_len,
+	execute_stack_op (fs->regs.cfa_exp, fs->regs.cfa_exp_len,
 			  cache->addr_size, this_frame, 0);
       break;