re PR c/41935 (ICE : tree check: expected integer_cst, have nop_expr in int_cst_value...

	PR middle-end/41935
	* c-common.c (fold_offsetof_1) <case ARRAY_REF>: Don't crash for VLAs
	or non-constant index, allow index one past the last element and
	allow exceeding array bound in arrays that might be used as flexible
	array members.

	* gcc.dg/pr41935.c: New test.
	* c-c++-common/pr41935.c: New test.
	* c-c++-common/builtin-offsetof.c (f0): Allow index one past the last
	element.
	* gcc.c-torture/execute/pr41935.c: New test.

From-SVN: r153962

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index a39ecba33d726401322ea6b5d1ab3ed869e8e366..70ed436e13aaeeceb1383cd99de054f9944487e6 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2009-11-06  Jakub Jelinek  <jakub@redhat.com>
+
+       PR middle-end/41935
+       * c-common.c (fold_offsetof_1) <case ARRAY_REF>: Don't crash for VLAs
+       or non-constant index, allow index one past the last element and
+       allow exceeding array bound in arrays that might be used as flexible
+       array members.
+
 2009-11-05  Richard Henderson  <rth@redhat.com>
 
        * config/i386/ia32intrin.h: Protect CRC32 builtins with __SSE4_2__.

diff --git a/gcc/c-common.c b/gcc/c-common.c
index a9ca9608db18197e59eeb8b060e13dabd14ba9ff..20b24f0c3c288a1d227da9801b467a221f4cbc4d 100644 (file)
--- a/gcc/c-common.c
+++ b/gcc/c-common.c
@@ -8398,14 +8398,46 @@ fold_offsetof_1 (tree expr, tree stop_ref)
       off = size_binop (MULT_EXPR, TYPE_SIZE_UNIT (TREE_TYPE (expr)), t);
 
       /* Check if the offset goes beyond the upper bound of the array.  */
-      {
-       tree nelts = array_type_nelts (TREE_TYPE (TREE_OPERAND (expr, 0)));
-        HOST_WIDE_INT index = int_cst_value (t);
-       if (index > int_cst_value (nelts))
-         warning (OPT_Warray_bounds,
-                  "index %wd denotes an offset greater than size of %qT",
-                  index, TREE_TYPE (TREE_OPERAND (expr, 0)));
-      }
+      if (code == PLUS_EXPR && TREE_CODE (t) == INTEGER_CST)
+       {
+         tree upbound = array_ref_up_bound (expr);
+         if (upbound != NULL_TREE
+             && TREE_CODE (upbound) == INTEGER_CST
+             && !tree_int_cst_equal (upbound,
+                                     TYPE_MAX_VALUE (TREE_TYPE (upbound))))
+           {
+             upbound = size_binop (PLUS_EXPR, upbound,
+                                   build_int_cst (TREE_TYPE (upbound), 1));
+             if (tree_int_cst_lt (upbound, t))
+               {
+                 tree v;
+
+                 for (v = TREE_OPERAND (expr, 0);
+                      TREE_CODE (v) == COMPONENT_REF;
+                      v = TREE_OPERAND (v, 0))
+                   if (TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
+                       == RECORD_TYPE)
+                     {
+                       tree fld_chain = TREE_CHAIN (TREE_OPERAND (v, 1));
+                       for (; fld_chain; fld_chain = TREE_CHAIN (fld_chain))
+                         if (TREE_CODE (fld_chain) == FIELD_DECL)
+                           break;
+
+                       if (fld_chain)
+                         break;
+                     }
+                 /* Don't warn if the array might be considered a poor
+                    man's flexible array member with a very permissive
+                    definition thereof.  */
+                 if (TREE_CODE (v) == ARRAY_REF
+                     || TREE_CODE (v) == COMPONENT_REF)
+                   warning (OPT_Warray_bounds,
+                            "index %E denotes an offset "
+                            "greater than size of %qT",
+                            t, TREE_TYPE (TREE_OPERAND (expr, 0)));
+               }
+           }
+       }
       break;
 
     case COMPOUND_EXPR:

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 2aba6077d226e053a0c191d1a96348c56ccb12b2..04ce93904a1e6d74397ee7d986cd320162307fa9 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,12 @@
+2009-11-06  Jakub Jelinek  <jakub@redhat.com>
+
+       PR middle-end/41935
+       * gcc.dg/pr41935.c: New test.
+       * c-c++-common/pr41935.c: New test.
+       * c-c++-common/builtin-offsetof.c (f0): Allow index one past the last
+       element.
+       * gcc.c-torture/execute/pr41935.c: New test.
+
 2009-11-05  Jason Merrill  <jason@redhat.com>
 
        PR c++/34180

diff --git a/gcc/testsuite/c-c++-common/builtin-offsetof.c b/gcc/testsuite/c-c++-common/builtin-offsetof.c
index 0ab498acd0917372efe63d7d065e113a438e8114..6d97775467d31675dedb01c40ab5bce03d702ba5 100644 (file)
--- a/gcc/testsuite/c-c++-common/builtin-offsetof.c
+++ b/gcc/testsuite/c-c++-common/builtin-offsetof.c
@@ -21,9 +21,9 @@ f0 ()
   __builtin_offsetof(struct A, p[0]); // { dg-error "non constant address" }
   __builtin_offsetof(struct B, p[0]); // OK
   __builtin_offsetof(struct B, p[9]); // OK
-  __builtin_offsetof(struct B, p[10]); // { dg-warning "greater than size" }
+  __builtin_offsetof(struct B, p[10]); // OK
+  __builtin_offsetof(struct B, p[11]); // { dg-warning "greater than size" }
   __builtin_offsetof(struct B, a.p); // OK
   __builtin_offsetof(struct B, p[0]); // OK
   __builtin_offsetof(struct B, a.p[0]); // { dg-error "non constant address" }
 }
-

diff --git a/gcc/testsuite/c-c++-common/pr41935.c b/gcc/testsuite/c-c++-common/pr41935.c
new file mode 100644 (file)
index 0000000..3279e75
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/pr41935.c
@@ -0,0 +1,70 @@
+/* { dg-options "-Warray-bounds" } */
+/* { dg-do compile } */
+
+struct A
+{
+  int i;
+  char p[1];
+};
+
+struct B
+{
+  struct A a;
+  int i;
+};
+
+struct C
+{
+  int i;
+  struct A a;
+};
+
+union D
+{
+  char p[1];
+  struct A a;
+  struct B b;
+  struct C c;
+};
+
+struct E
+{
+  int i;
+  union D d;
+};
+
+struct F
+{
+  union D d;
+  int i;
+};
+
+union G
+{
+  int i;
+  union D d;
+};
+
+void
+f0 ()
+{
+  __builtin_offsetof (struct A, p[4]); /* OK */
+  __builtin_offsetof (struct B, a.p[4]); /* { dg-warning "greater than size" } */
+  __builtin_offsetof (struct C, a.p[4]); /* OK */
+  __builtin_offsetof (union D, p[4]); /* OK */
+  __builtin_offsetof (union D, a.p[4]); /* OK */
+  __builtin_offsetof (union D, b.a.p[4]); /* { dg-warning "greater than size" } */
+  __builtin_offsetof (union D, c.a.p[4]); /* OK */
+  __builtin_offsetof (struct E, d.p[4]); /* OK */
+  __builtin_offsetof (struct E, d.a.p[4]); /* OK */
+  __builtin_offsetof (struct E, d.b.a.p[4]); /* { dg-warning "greater than size" } */
+  __builtin_offsetof (struct E, d.c.a.p[4]); /* OK */
+  __builtin_offsetof (struct F, d.p[4]); /* { dg-warning "greater than size" } */
+  __builtin_offsetof (struct F, d.a.p[4]); /* { dg-warning "greater than size" } */
+  __builtin_offsetof (struct F, d.b.a.p[4]); /* { dg-warning "greater than size" } */
+  __builtin_offsetof (struct F, d.c.a.p[4]); /* { dg-warning "greater than size" } */
+  __builtin_offsetof (union G, d.p[4]); /* OK */
+  __builtin_offsetof (union G, d.a.p[4]); /* OK */
+  __builtin_offsetof (union G, d.b.a.p[4]); /* { dg-warning "greater than size" } */
+  __builtin_offsetof (union G, d.c.a.p[4]); /* OK */
+}

diff --git a/gcc/testsuite/gcc.c-torture/execute/pr41935.c b/gcc/testsuite/gcc.c-torture/execute/pr41935.c
new file mode 100644 (file)
index 0000000..ef8d08c
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr41935.c
@@ -0,0 +1,25 @@
+/* PR middle-end/41935 */
+
+extern void abort (void);
+
+long int
+foo (int n, int i, int j)
+{
+  typedef int T[n];
+  struct S { int a; T b[n]; };
+  return __builtin_offsetof (struct S, b[i][j]);
+}
+
+int
+main (void)
+{
+  typedef int T[5];
+  struct S { int a; T b[5]; };
+  if (foo (5, 2, 3)
+      != __builtin_offsetof (struct S, b) + (5 * 2 + 3) * sizeof (int))
+    abort ();
+  if (foo (5, 5, 5)
+      != __builtin_offsetof (struct S, b) + (5 * 5 + 5) * sizeof (int))
+    abort ();
+  return 0;
+}

diff --git a/gcc/testsuite/gcc.dg/pr41935.c b/gcc/testsuite/gcc.dg/pr41935.c
new file mode 100644 (file)
index 0000000..e6a1b28
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr41935.c
@@ -0,0 +1,25 @@
+/* PR middle-end/41935 */
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+extern void abort (void);
+struct A { int a; int b[10]; };
+
+int
+foo (struct A *p)
+{
+  return __builtin_offsetof (struct A, b[p->a]);
+}
+
+int
+main ()
+{
+  struct A a;
+  a.a = 7;
+  if (foo (&a) != 7 * sizeof (int) + __builtin_offsetof (struct A, b))
+    abort ();
+  a.a = 2;
+  if (foo (&a) != 2 * sizeof (int) + __builtin_offsetof (struct A, b))
+    abort ();
+  return 0;
+}