Import the setjump/longjump exception handling fixes from GCC 2.95.3.test3

that were removed from GCC 2.95.3.test4 and the subsequent release due
to problems on HP-UX.  However, they work just fine on all the BSD's.

W/o these patches the following program segmentation faults if compiled
with -O2 (but not -Os or -O or -O0):

#include <stdio.h>

class A {
public:
  A() { printf("c'tor A\n"); }
  ~A(){ printf("d'tor A\n"); }
};

class foo : public A {
public:
  foo()  { printf("C'tor foo\n"); throw 8; }
  ~foo() { printf("D'tor foo\n"); }
};

int main(){
  try { foo fii; }
  catch (int){ printf("catch ...\n"); }
  return 0;
}

1 files changed, 88 insertions, 52 deletions

diff --git a/contrib/gcc/expr.c b/contrib/gcc/expr.c
index e3fe1f8f9f13..b8bcc86d5979 100644
--- a/contrib/gcc/expr.c
+++ b/contrib/gcc/expr.c
@@ -192,6 +192,7 @@ static rtx expand_builtin	PROTO((tree, rtx, rtx,
 static int apply_args_size	PROTO((void));
 static int apply_result_size	PROTO((void));
 static rtx result_vector	PROTO((int, rtx));
+static rtx expand_builtin_setjmp PROTO((tree, rtx));
 static rtx expand_builtin_apply_args PROTO((void));
 static rtx expand_builtin_apply	PROTO((rtx, rtx, rtx));
 static void expand_builtin_return PROTO((rtx));
@@ -8544,44 +8545,29 @@ expand_builtin_return_addr (fndecl_code, count, tem)
   return tem;
 }
 
-/* __builtin_setjmp is passed a pointer to an array of five words (not
-   all will be used on all machines).  It operates similarly to the C
-   library function of the same name, but is more efficient.  Much of
-   the code below (and for longjmp) is copied from the handling of
-   non-local gotos.
-
-   NOTE: This is intended for use by GNAT and the exception handling
-   scheme in the compiler and will only work in the method used by
-   them.  */
+/* Construct the leading half of a __builtin_setjmp call.  Control will
+   return to RECEIVER_LABEL.  This is used directly by sjlj exception
+   handling code.  */
 
-rtx
-expand_builtin_setjmp (buf_addr, target, first_label, next_label)
+void
+expand_builtin_setjmp_setup (buf_addr, receiver_label)
      rtx buf_addr;
-     rtx target;
-     rtx first_label, next_label;
+     rtx receiver_label;
 {
-  rtx lab1 = gen_label_rtx ();
   enum machine_mode sa_mode = STACK_SAVEAREA_MODE (SAVE_NONLOCAL);
-  enum machine_mode value_mode;
   rtx stack_save;
 
-  value_mode = TYPE_MODE (integer_type_node);
-
 #ifdef POINTERS_EXTEND_UNSIGNED
   buf_addr = convert_memory_address (Pmode, buf_addr);
 #endif
 
   buf_addr = force_reg (Pmode, buf_addr);
 
-  if (target == 0 || GET_CODE (target) != REG
-      || REGNO (target) < FIRST_PSEUDO_REGISTER)
-    target = gen_reg_rtx (value_mode);
-
   emit_queue ();
 
-  /* We store the frame pointer and the address of lab1 in the buffer
-     and use the rest of it for the stack save area, which is
-     machine-dependent.  */
+  /* We store the frame pointer and the address of receiver_label in
+     the buffer and use the rest of it for the stack save area, which
+     is machine-dependent.  */
 
 #ifndef BUILTIN_SETJMP_FRAME_VALUE
 #define BUILTIN_SETJMP_FRAME_VALUE virtual_stack_vars_rtx
@@ -8593,7 +8579,7 @@ expand_builtin_setjmp (buf_addr, target, first_label, next_label)
 		  (gen_rtx_MEM (Pmode,
 				plus_constant (buf_addr,
 					       GET_MODE_SIZE (Pmode)))),
-		  force_reg (Pmode, gen_rtx_LABEL_REF (Pmode, lab1)));
+		  force_reg (Pmode, gen_rtx_LABEL_REF (Pmode, receiver_label)));
 
   stack_save = gen_rtx_MEM (sa_mode,
 			    plus_constant (buf_addr,
@@ -8606,20 +8592,22 @@ expand_builtin_setjmp (buf_addr, target, first_label, next_label)
     emit_insn (gen_builtin_setjmp_setup (buf_addr));
 #endif
 
-  /* Set TARGET to zero and branch to the first-time-through label.  */
-  emit_move_insn (target, const0_rtx);
-  emit_jump_insn (gen_jump (first_label));
-  emit_barrier ();
-  emit_label (lab1);
-
-  /* Tell flow about the strange goings on.  Putting `lab1' on
-     `nonlocal_goto_handler_labels' to indicates that function
-     calls may traverse the arc back to this label.  */
+  /* Tell optimize_save_area_alloca that extra work is going to
+     need to go on during alloca.  */
+  current_function_calls_setjmp = 1;
 
+  /* Set this so all the registers get saved in our frame; we need to be
+     able to copy the saved values for any registers from frames we unwind. */
   current_function_has_nonlocal_label = 1;
-  nonlocal_goto_handler_labels =
-    gen_rtx_EXPR_LIST (VOIDmode, lab1, nonlocal_goto_handler_labels);
+}
 
+/* Construct the trailing part of a __builtin_setjmp call.
+   This is used directly by sjlj exception handling code.  */
+ 
+void
+expand_builtin_setjmp_receiver (receiver_label)
+      rtx receiver_label ATTRIBUTE_UNUSED;
+{
   /* Clobber the FP when we get here, so we have to make sure it's
      marked as used by this function.  */
   emit_insn (gen_rtx_USE (VOIDmode, hard_frame_pointer_rtx));
@@ -8666,7 +8654,7 @@ expand_builtin_setjmp (buf_addr, target, first_label, next_label)
 
 #ifdef HAVE_builtin_setjmp_receiver
   if (HAVE_builtin_setjmp_receiver)
-    emit_insn (gen_builtin_setjmp_receiver (lab1));
+    emit_insn (gen_builtin_setjmp_receiver (receiver_label));
   else
 #endif
 #ifdef HAVE_nonlocal_goto_receiver
@@ -8678,11 +8666,67 @@ expand_builtin_setjmp (buf_addr, target, first_label, next_label)
 	; /* Nothing */
       }
 
-  /* Set TARGET, and branch to the next-time-through label.  */
-  emit_move_insn (target, const1_rtx);
-  emit_jump_insn (gen_jump (next_label));
+  /* @@@ This is a kludge.  Not all machine descriptions define a blockage
+     insn, but we must not allow the code we just generated to be reordered
+     by scheduling.  Specifically, the update of the frame pointer must
+     happen immediately, not later.  So emit an ASM_INPUT to act as blockage
+     insn.  */
+  emit_insn (gen_rtx_ASM_INPUT (VOIDmode, ""));
+}
+
+
+/* __builtin_setjmp is passed a pointer to an array of five words (not
+   all will be used on all machines).  It operates similarly to the C
+   library function of the same name, but is more efficient.  Much of
+   the code below (and for longjmp) is copied from the handling of
+   non-local gotos.
+
+   NOTE: This is intended for use by GNAT and the exception handling
+   scheme in the compiler and will only work in the method used by
+   them.  */
+
+static rtx
+expand_builtin_setjmp (arglist, target)
+     tree arglist;
+     rtx target;
+{
+  rtx buf_addr, next_lab, cont_lab;
+
+  if (arglist == 0
+      || TREE_CODE (TREE_TYPE (TREE_VALUE (arglist))) != POINTER_TYPE)
+    return NULL_RTX;
+
+  if (target == 0 || GET_CODE (target) != REG
+      || REGNO (target) < FIRST_PSEUDO_REGISTER)
+    target = gen_reg_rtx (TYPE_MODE (integer_type_node));
+
+  buf_addr = expand_expr (TREE_VALUE (arglist), NULL_RTX, VOIDmode, 0);
+
+  next_lab = gen_label_rtx ();
+  cont_lab = gen_label_rtx ();
+
+  expand_builtin_setjmp_setup (buf_addr, next_lab);
+
+  /* Set TARGET to zero and branch to the continue label.  */
+  emit_move_insn (target, const0_rtx);
+  emit_jump_insn (gen_jump (cont_lab));
   emit_barrier ();
+  emit_label (next_lab);
 
+  expand_builtin_setjmp_receiver (next_lab);
+
+  /* Set TARGET to one.  */
+  emit_move_insn (target, const1_rtx);
+  emit_label (cont_lab);
+
+  /* Tell flow about the strange goings on.  Putting `next_lab' on
+     `nonlocal_goto_handler_labels' to indicates that function
+     calls may traverse the arc back to this label.  */
+
+  current_function_has_nonlocal_label = 1;
+  nonlocal_goto_handler_labels
+    = gen_rtx_EXPR_LIST (VOIDmode, next_lab, nonlocal_goto_handler_labels);
+ 
   return target;
 }
 
@@ -9703,18 +9747,10 @@ expand_builtin (exp, target, subtarget, mode, ignore)
 #endif
 
     case BUILT_IN_SETJMP:
-      if (arglist == 0
-	  || TREE_CODE (TREE_TYPE (TREE_VALUE (arglist))) != POINTER_TYPE)
-	break;
-      else
-	{
-	  rtx buf_addr = expand_expr (TREE_VALUE (arglist), subtarget,
-				      VOIDmode, 0);
-	  rtx lab = gen_label_rtx ();
-	  rtx ret = expand_builtin_setjmp (buf_addr, target, lab, lab);
-	  emit_label (lab);
-	  return ret;
-	}
+      target = expand_builtin_setjmp (arglist, target);
+      if (target)
+	return target;
+      break;
 
       /* __builtin_longjmp is passed a pointer to an array of five words.
 	 It's similar to the C library longjmp function but works with