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From dfb9470529df202844f4b5dfe757ff07fa9bd27f Mon Sep 17 00:00:00 2001
From: jason <jason@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Fri, 6 May 2011 21:58:30 +0000
Subject: [PATCH] PR c++/48446
* decl.c (stabilize_save_expr_r, stabilize_vla_size): New.
(grokdeclarator): Use stabilize_vla_size.
* init.c (get_temp_regvar): No longer static.
* cp-tree.h: Declare it.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/branches/gcc-4_6-branch@173514 138bc75d-0d04-0410-961f-82ee72b054a4
index 9fbca57..be61dad 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -4958,6 +4958,7 @@ extern tree build_offset_ref (tree, tree, bool);
extern tree build_new (VEC(tree,gc) **, tree, tree,
VEC(tree,gc) **, int,
tsubst_flags_t);
+extern tree get_temp_regvar (tree, tree);
extern tree build_vec_init (tree, tree, tree, bool, int,
tsubst_flags_t);
extern tree build_delete (tree, tree,
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 6f8bb9f..74bae0b 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -7499,6 +7499,39 @@ check_static_variable_definition (tree decl, tree type)
return 0;
}
+/* *expr_p is part of the TYPE_SIZE of a variably-sized array. If any
+ SAVE_EXPRs in *expr_p wrap expressions with side-effects, break those
+ expressions out into temporary variables so that walk_tree doesn't
+ step into them (c++/15764). */
+
+static tree
+stabilize_save_expr_r (tree *expr_p, int *walk_subtrees, void *data)
+{
+ struct pointer_set_t *pset = (struct pointer_set_t *)data;
+ tree expr = *expr_p;
+ if (TREE_CODE (expr) == SAVE_EXPR)
+ {
+ tree op = TREE_OPERAND (expr, 0);
+ cp_walk_tree (&op, stabilize_save_expr_r, data, pset);
+ if (TREE_SIDE_EFFECTS (op))
+ TREE_OPERAND (expr, 0) = get_temp_regvar (TREE_TYPE (op), op);
+ *walk_subtrees = 0;
+ }
+ else if (!EXPR_P (expr) || !TREE_SIDE_EFFECTS (expr))
+ *walk_subtrees = 0;
+ return NULL;
+}
+
+/* Entry point for the above. */
+
+static void
+stabilize_vla_size (tree size)
+{
+ struct pointer_set_t *pset = pointer_set_create ();
+ /* Break out any function calls into temporary variables. */
+ cp_walk_tree (&size, stabilize_save_expr_r, pset, pset);
+}
+
/* Given the SIZE (i.e., number of elements) in an array, compute an
appropriate index type for the array. If non-NULL, NAME is the
name of the thing being declared. */
@@ -8951,7 +8984,12 @@ grokdeclarator (const cp_declarator *declarator,
&& (decl_context == NORMAL || decl_context == FIELD)
&& at_function_scope_p ()
&& variably_modified_type_p (type, NULL_TREE))
- finish_expr_stmt (TYPE_SIZE (type));
+ {
+ /* First break out any side-effects. */
+ stabilize_vla_size (TYPE_SIZE (type));
+ /* And then force evaluation of the SAVE_EXPR. */
+ finish_expr_stmt (TYPE_SIZE (type));
+ }
if (declarator->kind == cdk_reference)
{
@@ -9026,6 +9064,14 @@ grokdeclarator (const cp_declarator *declarator,
}
}
+ /* We need to stabilize side-effects in VLA sizes for regular array
+ declarations too, not just pointers to arrays. */
+ if (type != error_mark_node && !TYPE_NAME (type)
+ && (decl_context == NORMAL || decl_context == FIELD)
+ && at_function_scope_p ()
+ && variably_modified_type_p (type, NULL_TREE))
+ stabilize_vla_size (TYPE_SIZE (type));
+
/* A `constexpr' specifier used in an object declaration declares
the object as `const'. */
if (constexpr_p && innermost_code != cdk_function)
diff --git a/gcc/cp/init.c b/gcc/cp/init.c
index 4798257..ff94b71 100644
--- a/gcc/cp/init.c
+++ b/gcc/cp/init.c
@@ -45,7 +45,6 @@ static void expand_virtual_init (tree, tree);
static tree sort_mem_initializers (tree, tree);
static tree initializing_context (tree);
static void expand_cleanup_for_base (tree, tree);
-static tree get_temp_regvar (tree, tree);
static tree dfs_initialize_vtbl_ptrs (tree, void *);
static tree build_dtor_call (tree, special_function_kind, int);
static tree build_field_list (tree, tree, int *);
@@ -2871,7 +2870,7 @@ create_temporary_var (tree type)
things when it comes time to do final cleanups (which take place
"outside" the binding contour of the function). */
-static tree
+tree
get_temp_regvar (tree type, tree init)
{
tree decl;
new file mode 100644
index 0000000..401c4e0
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/vla-1.c
@@ -0,0 +1,21 @@
+/* Test that changes to a variable are reflected in a VLA later in the
+ expression. */
+/* { dg-options "" } */
+
+#ifdef __cplusplus
+extern "C"
+#endif
+void abort();
+
+int i = 4;
+int f()
+{
+ return i;
+}
+
+int main()
+{
+ if (i+=2, sizeof(*(int(*)[f()])0) != 6*sizeof(int))
+ abort();
+ return 0;
+}
diff --git a/gcc/testsuite/g++.dg/ext/vla10.C b/gcc/testsuite/g++.dg/ext/vla10.C
new file mode 100644
index 0000000..17cdb2f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/vla10.C
@@ -0,0 +1,32 @@
+// PR c++/48446
+// { dg-options "" }
+
+template<typename T>
+struct A
+{
+ ~A ();
+ T *operator-> () const;
+};
+
+struct B
+{
+ typedef A <B> P;
+ static P foo (int);
+};
+
+struct C
+{
+ typedef A<C> P;
+ static const int c = 80;
+};
+
+C::P bar ();
+
+void
+baz ()
+{
+ char z[bar ()->c];
+ {
+ B::P m = B::foo (sizeof (z));
+ }
+}
--
1.7.0.4
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