PR c/6940

	* doc/invoke.texi: Document -Wsizeof-array-argument.
c-family/
	* c.opt (Wsizeof-array-argument): New option.
c/
	* c-decl.c (grokdeclarator): Set C_ARRAY_PARAMETER.
	* c-tree.h (C_ARRAY_PARAMETER): Define.
	* c-typeck.c (c_expr_sizeof_expr): Warn when using sizeof on an array
	function parameter.
cp/
	* cp-tree.h (DECL_ARRAY_PARAMETER_P): Define.
	* decl.c (grokdeclarator): Set DECL_ARRAY_PARAMETER_P.
	* typeck.c (cxx_sizeof_expr): Warn when using sizeof on an array
	function parameter.
testsuite/
	* c-c++-common/Wsizeof-pointer-memaccess1.c: Use
	-Wno-sizeof-array-argument.
	* c-c++-common/Wsizeof-pointer-memaccess2.c: Likewise.
	* g++.dg/warn/Wsizeof-pointer-memaccess-1.C: Likewise.
	* gcc.dg/Wsizeof-pointer-memaccess1.c: Likewise.
	* g++.dg/torture/Wsizeof-pointer-memaccess1.C: Likewise.
	* g++.dg/torture/Wsizeof-pointer-memaccess2.C: Likewise.
	* gcc.dg/torture/Wsizeof-pointer-memaccess1.c: Likewise.
	* c-c++-common/sizeof-array-argument.c: New test.
	* gcc.dg/vla-5.c: Add dg-warnings.
../libgomp/
	* testsuite/libgomp.c/appendix-a/a.29.1.c (f): Add dg-warnings.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@212312 138bc75d-0d04-0410-961f-82ee72b054a4

4 files changed, 24 insertions, 0 deletions

diff --git a/gcc/c/ChangeLog b/gcc/c/ChangeLog
index 68abca4dfb1..80ad172c596 100644
--- a/gcc/c/ChangeLog
+++ b/gcc/c/ChangeLog
@@ -1,3 +1,11 @@
+2014-07-06  Marek Polacek  <polacek@redhat.com>
+
+	PR c/6940
+	* c-decl.c (grokdeclarator): Set C_ARRAY_PARAMETER.
+	* c-tree.h (C_ARRAY_PARAMETER): Define.
+	* c-typeck.c (c_expr_sizeof_expr): Warn when using sizeof on an array
+	function parameter.
+
 2014-07-02  Jan Hubicka  <hubicka@ucw.cz>
 	    Chen Gang <gang.chen.5i5j@gmail.com>
 
diff --git a/gcc/c/c-decl.c b/gcc/c/c-decl.c
index 3dec90b23ed..0ca2e0d58f4 100644
--- a/gcc/c/c-decl.c
+++ b/gcc/c/c-decl.c
@@ -6103,6 +6103,7 @@ grokdeclarator (const struct c_declarator *declarator,
     if (decl_context == PARM)
       {
 	tree promoted_type;
+	bool array_parameter_p = false;
 
 	/* A parameter declared as an array of T is really a pointer to T.
 	   One declared as a function is really a pointer to a function.  */
@@ -6124,6 +6125,7 @@ grokdeclarator (const struct c_declarator *declarator,
 			  "attributes in parameter array declarator ignored");
 
 	    size_varies = false;
+	    array_parameter_p = true;
 	  }
 	else if (TREE_CODE (type) == FUNCTION_TYPE)
 	  {
@@ -6148,6 +6150,7 @@ grokdeclarator (const struct c_declarator *declarator,
 			   PARM_DECL, declarator->u.id, type);
 	if (size_varies)
 	  C_DECL_VARIABLE_SIZE (decl) = 1;
+	C_ARRAY_PARAMETER (decl) = array_parameter_p;
 
 	/* Compute the type actually passed in the parmlist,
 	   for the case where there is no prototype.
diff --git a/gcc/c/c-tree.h b/gcc/c/c-tree.h
index 133930f4a09..f97d0d5ba9b 100644
--- a/gcc/c/c-tree.h
+++ b/gcc/c/c-tree.h
@@ -66,6 +66,9 @@ along with GCC; see the file COPYING3.  If not see
 /* For a FUNCTION_DECL, nonzero if it was an implicit declaration.  */
 #define C_DECL_IMPLICIT(EXP) DECL_LANG_FLAG_2 (EXP)
 
+/* For a PARM_DECL, nonzero if it was declared as an array.  */
+#define C_ARRAY_PARAMETER(NODE) DECL_LANG_FLAG_0 (NODE)
+
 /* For FUNCTION_DECLs, evaluates true if the decl is built-in but has
    been declared.  */
 #define C_DECL_DECLARED_BUILTIN(EXP)		\
diff --git a/gcc/c/c-typeck.c b/gcc/c/c-typeck.c
index 35bfd149876..06fd565f770 100644
--- a/gcc/c/c-typeck.c
+++ b/gcc/c/c-typeck.c
@@ -2731,6 +2731,16 @@ c_expr_sizeof_expr (location_t loc, struct c_expr expr)
   else
     {
       bool expr_const_operands = true;
+
+      if (TREE_CODE (expr.value) == PARM_DECL
+	  && C_ARRAY_PARAMETER (expr.value))
+	{
+	  if (warning_at (loc, OPT_Wsizeof_array_argument,
+			  "%<sizeof%> on array function parameter %qE will "
+			  "return size of %qT", expr.value,
+			  expr.original_type))
+	    inform (DECL_SOURCE_LOCATION (expr.value), "declared here");
+	}
       tree folded_expr = c_fully_fold (expr.value, require_constant_value,
 				       &expr_const_operands);
       ret.value = c_sizeof (loc, TREE_TYPE (folded_expr));