Re: [PATCH] Properly check for _Cilk_spawn in return stmt (PR c/60197)

[Marek Polacek <polacek at redhat dot com>]

On Tue, Feb 18, 2014 at 10:06:14PM +0000, Iyer, Balaji V wrote:
> This is invalid.

Thanks.  In that case, this patch should error out on such invalid uses as
well, instead of ICEing.

Regtested/bootstrapped on x86_64-linux.

2014-02-19  Marek Polacek  <polacek@redhat.com>

	PR c/60197
c-family/
	* cilk.c (contains_cilk_spawn_stmt): New function.
	(contains_cilk_spawn_stmt_walker): Likewise.
	(recognize_spawn): Give error on invalid use of _Cilk_spawn.
	* c-common.h (contains_cilk_spawn_stmt): Add declaration.
c/
	* c-typeck.c (c_finish_return): Call contains_cilk_spawn_stmt instead
	of checking tree code.
cp/
	* typeck.c (check_return_expr): Call contains_cilk_spawn_stmt instead
	of checking tree code.
testsuite/
	* c-c++-common/cilk-plus/CK/pr60197.c: New test.
	* c-c++-common/cilk-plus/CK/pr60197-2.c: New test.

diff --git gcc/c-family/c-common.h gcc/c-family/c-common.h
index f074ab1..1099b10 100644
--- gcc/c-family/c-common.h
+++ gcc/c-family/c-common.h
@@ -1389,4 +1389,5 @@ extern tree make_cilk_frame (tree);
 extern tree create_cilk_function_exit (tree, bool, bool);
 extern tree cilk_install_body_pedigree_operations (tree);
 extern void cilk_outline (tree, tree *, void *);
+extern bool contains_cilk_spawn_stmt (tree);
 #endif /* ! GCC_C_COMMON_H */
diff --git gcc/c-family/cilk.c gcc/c-family/cilk.c
index f2179dfc..6a7bf4f 100644
--- gcc/c-family/cilk.c
+++ gcc/c-family/cilk.c
@@ -235,6 +235,9 @@ recognize_spawn (tree exp, tree *exp0)
       walk_tree (exp0, unwrap_cilk_spawn_stmt, NULL, NULL);
       spawn_found = true;
     }
+  /* _Cilk_spawn can't be wrapped in expression such as PLUS_EXPR.  */
+  else if (contains_cilk_spawn_stmt (exp))
+    error ("invalid use of %<_Cilk_spawn%>");
   return spawn_found;
 }
 
@@ -1292,3 +1295,25 @@ build_cilk_sync (void)
   TREE_SIDE_EFFECTS (sync) = 1;
   return sync;
 }
+
+/* Helper for contains_cilk_spawn_stmt, callback for walk_tree.  Return
+   non-null tree if TP contains CILK_SPAWN_STMT.  */
+
+static tree
+contains_cilk_spawn_stmt_walker (tree *tp, int *, void *)
+{
+  if (TREE_CODE (*tp) == CILK_SPAWN_STMT)
+    return *tp;
+  else
+    return NULL_TREE;
+}
+
+/* Returns true if EXPR or any of its subtrees contain CILK_SPAWN_STMT
+   node.  */
+
+bool
+contains_cilk_spawn_stmt (tree expr)
+{
+  return walk_tree (&expr, contains_cilk_spawn_stmt_walker, NULL, NULL)
+	 != NULL_TREE;
+}
diff --git gcc/c/c-typeck.c gcc/c/c-typeck.c
index 2b54290..7c4ba0e 100644
--- gcc/c/c-typeck.c
+++ gcc/c/c-typeck.c
@@ -9140,7 +9140,7 @@ c_finish_return (location_t loc, tree retval, tree origtype)
 	  return error_mark_node;
 	}
     }
-  if (flag_cilkplus && retval && TREE_CODE (retval) == CILK_SPAWN_STMT)
+  if (flag_cilkplus && retval && contains_cilk_spawn_stmt (retval))
     {
       error_at (loc, "use of %<_Cilk_spawn%> in a return statement is not "
 		"allowed");
diff --git gcc/cp/typeck.c gcc/cp/typeck.c
index 5fc0e6b..566411f 100644
--- gcc/cp/typeck.c
+++ gcc/cp/typeck.c
@@ -8328,7 +8328,7 @@ check_return_expr (tree retval, bool *no_warning)
 
   *no_warning = false;
 
-  if (flag_cilkplus && retval && TREE_CODE (retval) == CILK_SPAWN_STMT)
+  if (flag_cilkplus && retval && contains_cilk_spawn_stmt (retval))
     {
       error_at (EXPR_LOCATION (retval), "use of %<_Cilk_spawn%> in a return "
 		"statement is not allowed");
diff --git gcc/testsuite/c-c++-common/cilk-plus/CK/pr60197-2.c gcc/testsuite/c-c++-common/cilk-plus/CK/pr60197-2.c
index e69de29..1e5ca00 100644
--- gcc/testsuite/c-c++-common/cilk-plus/CK/pr60197-2.c
+++ gcc/testsuite/c-c++-common/cilk-plus/CK/pr60197-2.c
@@ -0,0 +1,35 @@
+/* PR c/60197 */
+/* { dg-do compile } */
+/* { dg-options "-fcilkplus" } */
+
+extern int foo (void);
+
+int
+fn1 (void)
+{
+  int i;
+  i = (_Cilk_spawn foo ()) + 1; /* { dg-error "invalid use of" } */
+  return i;
+}
+
+int
+fn2 (void)
+{
+  int i = (_Cilk_spawn foo ()) + 1; /* { dg-error "invalid use of" } */
+  return i;
+}
+
+int
+fn3 (int j, int k, int l)
+{
+  int i = (((((_Cilk_spawn foo ()) + 1) - l) * k) / j); /* { dg-error "invalid use of" } */
+  return i;
+}
+
+int
+fn4 (int j, int k, int l)
+{
+  int i;
+  i = (((((_Cilk_spawn foo ()) + 1) - l) * k) / j); /* { dg-error "invalid use of" } */
+  return i;
+}
diff --git gcc/testsuite/c-c++-common/cilk-plus/CK/pr60197.c gcc/testsuite/c-c++-common/cilk-plus/CK/pr60197.c
index e69de29..2b47d1e 100644
--- gcc/testsuite/c-c++-common/cilk-plus/CK/pr60197.c
+++ gcc/testsuite/c-c++-common/cilk-plus/CK/pr60197.c
@@ -0,0 +1,66 @@
+/* PR c/60197 */
+/* { dg-do compile } */
+/* { dg-options "-fcilkplus" } */
+
+extern int foo (void);
+extern int bar (int);
+
+int
+fn1 (void)
+{
+  return (_Cilk_spawn foo ()) * 2; /* { dg-error "in a return statement is not allowed" } */
+}
+
+int
+fn2 (void)
+{
+  return (_Cilk_spawn foo ()) > 2; /* { dg-error "in a return statement is not allowed" } */
+}
+
+int
+fn3 (int i, int j, int k)
+{
+  return ((((((_Cilk_spawn foo () + i) - j) * k) / j) | i) ^ k) ; /* { dg-error "in a return statement is not allowed" } */
+}
+
+int
+fn4 (int i, int j, int k)
+{
+  return (((((i - _Cilk_spawn foo ()) * k) / j) | i) ^ k); /* { dg-error "in a return statement is not allowed" } */
+}
+
+int
+fn5 (void)
+{
+  return _Cilk_spawn foo (); /* { dg-error "in a return statement is not allowed" } */
+}
+
+int
+fn6 (void)
+{
+  return _Cilk_spawn foo () + _Cilk_spawn foo (); /* { dg-error "in a return statement is not allowed" } */
+}
+
+int
+fn7 (void)
+{
+  return 5 % _Cilk_spawn foo (); /* { dg-error "in a return statement is not allowed" } */
+}
+
+int
+fn8 (void)
+{
+  return !_Cilk_spawn foo (); /* { dg-error "in a return statement is not allowed" } */
+}
+
+int
+fn9 (void)
+{
+  return foo () && _Cilk_spawn foo (); /* { dg-error "in a return statement is not allowed" } */
+}
+
+int
+fn10 (void)
+{
+  return bar (_Cilk_spawn foo ()); /* { dg-error "in a return statement is not allowed" } */
+}

	Marek