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

["Iyer, Balaji V" <balaji dot v dot iyer at intel dot com>]

> -----Original Message-----
> From: gcc-patches-owner@gcc.gnu.org [mailto:gcc-patches-
> owner@gcc.gnu.org] On Behalf Of Marek Polacek
> Sent: Wednesday, February 19, 2014 8:39 AM
> To: Iyer, Balaji V
> Cc: gcc-patches@gcc.gnu.org
> Subject: Re: [PATCH] Properly check for _Cilk_spawn in return stmt (PR
> c/60197)
> 
> 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" } */ }
> 

Hi Marek,
	This patch looks OK to me. I don't have approval rights, so I can't approve it.

Thanks,

Balaji V. Iyer.

> 	Marek