Infinite loop or abort on malformed C

[Zack Weinberg]

On Fri, 16 Apr 1999 09:33:49 -0400, Zack Weinberg wrote:
>
>This fragment [...] sends the current development tree into a
>near-infinite loop, eventually running out of memory and dying with
>SIGBUS.  1.1.x is a bit more polite, it just ICEs.

Here is a patch.

zw

1999-04-17 09:36 -0400  Zack Weinberg  <zack@rabi.phys.columbia.edu>

	* expr.c (emit_move_insn_1): Abort on invalid mode.
	(compare): If exp contains an ERROR_MARK, punt.

===================================================================
Index: expr.c
--- expr.c	1999/04/15 22:52:22	1.138
+++ expr.c	1999/04/17 13:35:34
@@ -2565,6 +2565,9 @@
   enum mode_class class = GET_MODE_CLASS (mode);
   int i;
 
+  if (mode >= MAX_MACHINE_MODE)
+      abort ();
+
   if (mov_optab->handlers[(int) mode].insn_code != CODE_FOR_nothing)
     return
       emit_insn (GEN_FCN (mov_optab->handlers[(int) mode].insn_code) (x, y));
@@ -11205,14 +11208,22 @@
      register tree exp;
      enum rtx_code signed_code, unsigned_code;
 {
-  register rtx op0
-    = expand_expr (TREE_OPERAND (exp, 0), NULL_RTX, VOIDmode, 0);
-  register rtx op1
-    = expand_expr (TREE_OPERAND (exp, 1), NULL_RTX, VOIDmode, 0);
-  register tree type = TREE_TYPE (TREE_OPERAND (exp, 0));
-  register enum machine_mode mode = TYPE_MODE (type);
-  int unsignedp = TREE_UNSIGNED (type);
-  enum rtx_code code = unsignedp ? unsigned_code : signed_code;
+  register rtx op0, op1;
+  register tree type;
+  register enum machine_mode mode;
+  int unsignedp;
+  enum rtx_code code;
+
+  /* Don't crash if the comparison was erroneous.  */
+  op0 = expand_expr (TREE_OPERAND (exp, 0), NULL_RTX, VOIDmode, 0);
+  if (TREE_CODE (TREE_OPERAND (exp, 0)) == ERROR_MARK)
+    return op0;
+  
+  op1 = expand_expr (TREE_OPERAND (exp, 1), NULL_RTX, VOIDmode, 0);
+  type = TREE_TYPE (TREE_OPERAND (exp, 0));
+  mode = TYPE_MODE (type);
+  unsignedp = TREE_UNSIGNED (type);
+  code = unsignedp ? unsigned_code : signed_code;
 
 #ifdef HAVE_canonicalize_funcptr_for_compare
   /* If function pointers need to be "canonicalized" before they can