c-ubsan.c (ubsan_instrument_bounds): Don't skip instrumenting flexible member array-like members if...

* c-ubsan.c (ubsan_instrument_bounds): Don't skip instrumenting
	flexible member array-like members if SANITIZE_BOUNDS_STRICT.

	* doc/invoke.texi: Document -fsanitize=bounds-strict.
	* flag-types.h (enum sanitize_code): Add SANITIZE_BOUNDS_STRICT, or it
	into SANITIZE_NONDEFAULT.
	* opts.c (common_handle_option): Handle -fsanitize=bounds-strict.

	* c-c++-common/ubsan/bounds-10.c: New test.

From-SVN: r222871

gcc/ChangeLog

@@ -1,3 +1,11 @@
+2015-05-07  Marek Polacek  <polacek@redhat.com>
+	    Martin Uecker  <uecker@eecs.berkeley.edu>
+
+	* doc/invoke.texi: Document -fsanitize=bounds-strict.
+	* flag-types.h (enum sanitize_code): Add SANITIZE_BOUNDS_STRICT, or it
+	into SANITIZE_NONDEFAULT.
+	* opts.c (common_handle_option): Handle -fsanitize=bounds-strict.
+
 2015-05-07  Uros Bizjak  <ubizjak@gmail.com>
 
 	PR target/66015

gcc/c-family/ChangeLog

@@ -1,3 +1,9 @@
+2015-05-07  Marek Polacek  <polacek@redhat.com>
+	    Martin Uecker  <uecker@eecs.berkeley.edu>
+
+	* c-ubsan.c (ubsan_instrument_bounds): Don't skip instrumenting
+	flexible member array-like members if SANITIZE_BOUNDS_STRICT.
+
 2015-05-05  Jason Merrill  <jason@redhat.com>
 
 	* c.opt (Wterminate): New.
@@ -9,8 +15,8 @@
 
 2015-04-29  Josh Triplett  <josh@joshtriplett.org>
 
-        * c-common.c (handle_section_attribute): Refactor to reduce
+	* c-common.c (handle_section_attribute): Refactor to reduce
-        nesting and distinguish between error cases.
+	nesting and distinguish between error cases.
 
 2015-04-29  Marek Polacek  <polacek@redhat.com>
 
@@ -30,7 +36,7 @@
 	* c-common.c (build_va_arg): Mark va_arg ap argument as addressable.
 
 2015-04-28  Eric Botcazou  <ebotcazou@adacore.com>
-            Pierre-Marie de Rodat  <derodat@adacore.com>
+	    Pierre-Marie de Rodat  <derodat@adacore.com>
 
 	* c-ada-spec.c (in_function): Delete.
 	(dump_generic_ada_node): Do not change in_function and remove the

gcc/c-family/c-ubsan.c

@@ -301,9 +301,11 @@ ubsan_instrument_bounds (location_t loc, tree array, tree *index,
     bound = fold_build2 (PLUS_EXPR, TREE_TYPE (bound), bound,
 			 build_int_cst (TREE_TYPE (bound), 1));
 
-  /* Detect flexible array members and suchlike.  */
+  /* Detect flexible array members and suchlike, unless
+     -fsanitize=bounds-strict.  */
   tree base = get_base_address (array);
-  if (TREE_CODE (array) == COMPONENT_REF
+  if ((flag_sanitize & SANITIZE_BOUNDS_STRICT) == 0
+      && TREE_CODE (array) == COMPONENT_REF
       && base && (TREE_CODE (base) == INDIRECT_REF
 		  || TREE_CODE (base) == MEM_REF))
     {

gcc/doc/invoke.texi

@@ -5736,6 +5736,13 @@ This option enables instrumentation of array bounds.  Various out of bounds
 accesses are detected.  Flexible array members, flexible array member-like
 arrays, and initializers of variables with static storage are not instrumented.
 
+@item -fsanitize=bounds-strict
+@opindex fsanitize=bounds-strict
+This option enables strict instrumentation of array bounds.  Most out of bounds
+accesses are detected, including flexible array members and flexible array
+member-like arrays.  Initializers of variables with static storage are not
+instrumented.
+
 @item -fsanitize=alignment
 @opindex fsanitize=alignment
 

gcc/flag-types.h

@@ -238,6 +238,7 @@ enum sanitize_code {
   SANITIZE_RETURNS_NONNULL_ATTRIBUTE = 1UL << 19,
   SANITIZE_OBJECT_SIZE = 1UL << 20,
   SANITIZE_VPTR = 1UL << 21,
+  SANITIZE_BOUNDS_STRICT = 1UL << 22,
   SANITIZE_UNDEFINED = SANITIZE_SHIFT | SANITIZE_DIVIDE | SANITIZE_UNREACHABLE
 		       | SANITIZE_VLA | SANITIZE_NULL | SANITIZE_RETURN
 		       | SANITIZE_SI_OVERFLOW | SANITIZE_BOOL | SANITIZE_ENUM
@@ -246,6 +247,7 @@ enum sanitize_code {
 		       | SANITIZE_RETURNS_NONNULL_ATTRIBUTE
 		       | SANITIZE_OBJECT_SIZE | SANITIZE_VPTR,
   SANITIZE_NONDEFAULT = SANITIZE_FLOAT_DIVIDE | SANITIZE_FLOAT_CAST
+			| SANITIZE_BOUNDS_STRICT
 };
 
 /* flag_vtable_verify initialization levels. */

gcc/opts.c

@@ -1584,6 +1584,8 @@ common_handle_option (struct gcc_options *opts,
 	      { "float-cast-overflow", SANITIZE_FLOAT_CAST,
 		sizeof "float-cast-overflow" - 1 },
 	      { "bounds", SANITIZE_BOUNDS, sizeof "bounds" - 1 },
+	      { "bounds-strict", SANITIZE_BOUNDS | SANITIZE_BOUNDS_STRICT,
+		sizeof "bounds-strict" - 1 },
 	      { "alignment", SANITIZE_ALIGNMENT, sizeof "alignment" - 1 },
 	      { "nonnull-attribute", SANITIZE_NONNULL_ATTRIBUTE,
 		sizeof "nonnull-attribute" - 1 },

gcc/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2015-05-07  Marek Polacek  <polacek@redhat.com>
+	    Martin Uecker  <uecker@eecs.berkeley.edu>
+
+	* c-c++-common/ubsan/bounds-10.c: New test.
+
 2015-05-06  David Malcolm  <dmalcolm@redhat.com>
 
 	* jit.dg/harness.h (set_options): Wrap with

gcc/testsuite/c-c++-common/ubsan/bounds-10.c

@@ -0,0 +1,16 @@
+/* { dg-do run } */
+/* { dg-options "-fsanitize=bounds-strict" } */
+
+struct V { int l; int a[1]; };
+
+int
+main (void)
+{
+  /* For strict, do instrument last array in a struct.  */
+  struct V *v = (struct V *) __builtin_malloc (sizeof (struct V) + 10);
+  v->a[1] = 1;
+
+  return 0;
+}
+
+/* { dg-output "index 1 out of bounds for type 'int \\\[1\\\]'" } */