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[PATCH] Fix ICE on sprintf (p, "%s") and miscompilation of sprintf (p, "a", q++) (PR middle-end/30473)
- From: Jakub Jelinek <jakub at redhat dot com>
- To: gcc-patches at gcc dot gnu dot org
- Date: Thu, 1 Feb 2007 08:33:23 -0500
- Subject: [PATCH] Fix ICE on sprintf (p, "%s") and miscompilation of sprintf (p, "a", q++) (PR middle-end/30473)
- Reply-to: Jakub Jelinek <jakub at redhat dot com>
Hi!
As shown on the attached testcases, fold_builtin_sprintf wasn't doing
proper checking of arguments (unlike expand_builtin_sprintf or other
fold_builtin_*printf* routines).
Fixed thusly, ok for 4.1/4.2/4.3?
BTW, I noticed we do all the fold_builtin_1 folding even with -O0, is
that desirable? Might make debugging harder.
2007-02-01 Jakub Jelinek <jakub@redhat.com>
PR middle-end/30473
* builtins.c (fold_builtin_sprintf): Do not attempt to optimize
sprintf (str, "%s"). Do not optimize sprintf (str, "nopercent", p++).
* gcc.dg/pr30473.c: New test.
* gcc.c-torture/execute/20070201-1.c: New test.
--- gcc/builtins.c.jj 2007-02-01 11:03:12.000000000 +0100
+++ gcc/builtins.c 2007-02-01 14:20:20.000000000 +0100
@@ -10553,6 +10553,7 @@ fold_builtin_sprintf (tree arglist, int
/* Get the destination string and the format specifier. */
dest = TREE_VALUE (arglist);
fmt = TREE_VALUE (TREE_CHAIN (arglist));
+ arglist = TREE_CHAIN (TREE_CHAIN (arglist));
/* Check whether the format is a literal string constant. */
fmt_str = c_getstr (fmt);
@@ -10573,6 +10574,10 @@ fold_builtin_sprintf (tree arglist, int
if (!fn)
return NULL_TREE;
+ /* Don't optimize sprintf (buf, "abc", ptr++). */
+ if (arglist)
+ return NULL_TREE;
+
/* Convert sprintf (str, fmt) into strcpy (str, fmt) when
'format' is known to contain no % formats. */
arglist = build_tree_list (NULL_TREE, fmt);
@@ -10591,8 +10596,12 @@ fold_builtin_sprintf (tree arglist, int
if (!fn)
return NULL_TREE;
+ /* Don't crash on sprintf (str1, "%s"). */
+ if (!arglist)
+ return NULL_TREE;
+
/* Convert sprintf (str1, "%s", str2) into strcpy (str1, str2). */
- orig = TREE_VALUE (TREE_CHAIN (TREE_CHAIN (arglist)));
+ orig = TREE_VALUE (arglist);
arglist = build_tree_list (NULL_TREE, orig);
arglist = tree_cons (NULL_TREE, dest, arglist);
if (!ignored)
--- gcc/testsuite/gcc.c-torture/execute/20070201-1.c.jj 2007-02-01 13:55:27.000000000 +0100
+++ gcc/testsuite/gcc.c-torture/execute/20070201-1.c 2007-02-01 13:53:37.000000000 +0100
@@ -0,0 +1,20 @@
+/* PR middle-end/30473 */
+
+extern int sprintf (char *, const char *, ...);
+extern void abort (void);
+
+char *
+foo (char *buf, char *p)
+{
+ sprintf (buf, "abcde", p++);
+ return p;
+}
+
+int
+main (void)
+{
+ char buf[6];
+ if (foo (buf, &buf[2]) != &buf[3])
+ abort ();
+ return 0;
+}
--- gcc/testsuite/gcc.dg/pr30473.c.jj 2007-02-01 13:39:55.000000000 +0100
+++ gcc/testsuite/gcc.dg/pr30473.c 2007-02-01 13:45:01.000000000 +0100
@@ -0,0 +1,13 @@
+/* PR middle-end/30473 */
+/* Make sure this doesn't ICE. */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+extern int sprintf (char *, const char *, ...);
+
+void
+foo (char *buf1, char *buf2)
+{
+ sprintf (buf1, "%s", "abcde");
+ sprintf (buf2, "%s");
+}
Jakub