File fix-unwind-endless.diff of Package libgcj43

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File fix-unwind-endless.diff of Package libgcj43

Newer codestreams use DW_CFA_undefined to mark the first frame,
without properly handling it we'd endlessly loop.

commit d02454a0d2e61b542b55db4f65bb6763d714a922
Author: jakub <jakub@138bc75d-0d04-0410-961f-82ee72b054a4>
Date:   Sat Apr 4 11:41:16 2009 +0000

* unwind-dw2.h (_Unwind_FrameState): Add REG_UNDEFINED enum value.
    	* unwind-dw2.c (execute_cfa_program): Set how to REG_UNDEFINED
    	instead of REG_UNSAVED for DW_CFA_undefined.
    	(uw_update_context_1): Handle REG_UNDEFINED the same as REG_UNSAVED.
    	(uw_update_context): If RA column is REG_UNDEFINED, mark it as
    	outermost frame.
    
    
    git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@145535 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/unwind-dw2.c b/gcc/unwind-dw2.c
index 3845467..6df1ffa 100644
--- a/gcc/unwind-dw2.c
+++ b/gcc/unwind-dw2.c
@@ -943,12 +943,16 @@ execute_cfa_program (const unsigned char *insn_ptr,
 	  fs->regs.reg[DWARF_REG_TO_UNWIND_COLUMN(reg)].how = REG_UNSAVED;
 	  break;
 
-	case DW_CFA_undefined:
 	case DW_CFA_same_value:
 	  insn_ptr = read_uleb128 (insn_ptr, &reg);
 	  fs->regs.reg[DWARF_REG_TO_UNWIND_COLUMN(reg)].how = REG_UNSAVED;
 	  break;
 
+	case DW_CFA_undefined:
+	  insn_ptr = read_uleb128 (insn_ptr, &reg);
+	  fs->regs.reg[DWARF_REG_TO_UNWIND_COLUMN(reg)].how = REG_UNDEFINED;
+	  break;
+
 	case DW_CFA_nop:
 	  break;
 
@@ -1319,6 +1323,7 @@ uw_update_context_1 (struct _Unwind_Context *context, _Unwind_FrameState *fs)
     switch (fs->regs.reg[i].how)
       {
       case REG_UNSAVED:
+      case REG_UNDEFINED:
 	break;
 
       case REG_SAVED_OFFSET:
@@ -1387,10 +1392,22 @@ uw_update_context (struct _Unwind_Context *context, _Unwind_FrameState *fs)
 {
   uw_update_context_1 (context, fs);
 
-  /* Compute the return address now, since the return address column
-     can change from frame to frame.  */
-  context->ra = __builtin_extract_return_addr
-    (_Unwind_GetPtr (context, fs->retaddr_column));
+  /* In general this unwinder doesn't make any distinction between
+     undefined and same_value rule.  Call-saved registers are assumed
+     to have same_value rule by default and explicit undefined
+     rule is handled like same_value.  The only exception is
+     DW_CFA_undefined on retaddr_column which is supposed to
+     mark outermost frame in DWARF 3.  */
+  if (fs->regs.reg[DWARF_REG_TO_UNWIND_COLUMN (fs->retaddr_column)].how
+      == REG_UNDEFINED)
+    /* uw_frame_state_for uses context->ra == 0 check to find outermost
+       stack frame.  */
+    context->ra = 0;
+  else
+    /* Compute the return address now, since the return address column
+       can change from frame to frame.  */
+    context->ra = __builtin_extract_return_addr
+      (_Unwind_GetPtr (context, fs->retaddr_column));
 }
 
 static void
diff --git a/gcc/unwind-dw2.h b/gcc/unwind-dw2.h
index db3a1ab..7f643c5 100644
--- a/gcc/unwind-dw2.h
+++ b/gcc/unwind-dw2.h
@@ -55,7 +55,8 @@ typedef struct
 	REG_SAVED_REG,
 	REG_SAVED_EXP,
 	REG_SAVED_VAL_OFFSET,
-	REG_SAVED_VAL_EXP
+	REG_SAVED_VAL_EXP,
+	REG_UNDEFINED
       } how;
     } reg[DWARF_FRAME_REGISTERS+1];

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File fix-unwind-endless.diff of Package libgcj43

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