* c-decl.c (shadow_tag_warned, grokdeclarator): Handle _Alignas

	specifiers.
	(build_null_declspecs): Initialize align_log and alignas_p fields.
	(declspecs_add_alignas): New.
	* c-parser.c (c_token_starts_declspecs): Handle RID_ALIGNAS.
	(c_parser_declspecs): Handle _Alignas specifiers.
	(c_parser_alignas_specifier): New.
	(c_parser_alignof_expression): Diagnose alignof use for non-C1X.
	Diagnose _Alignof (expression).
	* c-tree.h (struct c_declspecs): Add align_log and alignas_p
	fields.
	(declspecs_add_alignas): Declare.
	* ginclude/stddef.h (max_align_t): Define for C1X and C++11.
	* ginclude/stdalign.h: New.
	* Makefile.in (USER_H): Add stdalign.h.

c-family:
	* c-common.c (c_common_reswords): Add _Alignas and _Alignof.
	(c_sizeof_or_alignof_type): Diagnose alignof applied to a function
	type.
	(check_user_alignment): New.  Split out of
	handle_aligned_attribute.  Disallow integer constants with
	noninteger types.  Conditionally allow zero.
	(handle_aligned_attribute): Use check_user_alignment.
	* c-common.h (RID_ALIGNAS, check_user_alignment): New.

testsuite:
	* g++.dg/cpp0x/alignof3.C, gcc.dg/c1x-align-1.c,
	gcc.dg/c1x-align-2.c, gcc.dg/c1x-align-3.c, gcc.dg/c1x-align-4.c,
	gcc.dg/c90-align-1.c, gcc.dg/c99-align-1.c: New tests.
	* gcc.dg/gnu89-const-expr-1.c, gcc.dg/gnu90-const-expr-1.c,
	gcc.dg/gnu99-const-expr-1.c, gcc.dg/gnu99-static-1.c: Update
	expected diagnostics.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@181048 138bc75d-0d04-0410-961f-82ee72b054a4

3 files changed, 61 insertions, 16 deletions

diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog
index 1c8a6b412f3..3829411d726 100644
--- a/gcc/c-family/ChangeLog
+++ b/gcc/c-family/ChangeLog
@@ -1,3 +1,14 @@
+2011-11-06  Joseph Myers  <joseph@codesourcery.com>
+
+	* c-common.c (c_common_reswords): Add _Alignas and _Alignof.
+	(c_sizeof_or_alignof_type): Diagnose alignof applied to a function
+	type.
+	(check_user_alignment): New.  Split out of
+	handle_aligned_attribute.  Disallow integer constants with
+	noninteger types.  Conditionally allow zero.
+	(handle_aligned_attribute): Use check_user_alignment.
+	* c-common.h (RID_ALIGNAS, check_user_alignment): New.
+
 2011-11-06  Andrew MacLeod  <amacleod@redhat.com>
 	    Richard Henderson  <rth@redhat.com>
 
diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index aa5f3bf24aa..0329bc7e01c 100644
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -404,6 +404,8 @@ static int resort_field_decl_cmp (const void *, const void *);
 */
 const struct c_common_resword c_common_reswords[] =
 {
+  { "_Alignas",		RID_ALIGNAS,   D_CONLY },
+  { "_Alignof",		RID_ALIGNOF,   D_CONLY },
   { "_Bool",		RID_BOOL,      D_CONLY },
   { "_Complex",		RID_COMPLEX,	0 },
   { "_Imaginary",	RID_IMAGINARY, D_CONLY },
@@ -4332,7 +4334,18 @@ c_sizeof_or_alignof_type (location_t loc,
 	  value = size_one_node;
 	}
       else
-	value = size_int (FUNCTION_BOUNDARY / BITS_PER_UNIT);
+	{
+	  if (complain)
+	    {
+	      if (c_dialect_cxx ())
+		pedwarn (loc, OPT_pedantic, "ISO C++ does not permit "
+			 "%<alignof%> applied to a function type");
+	      else
+		pedwarn (loc, OPT_pedantic, "ISO C does not permit "
+			 "%<_Alignof%> applied to a function type");
+	    }
+	  value = size_int (FUNCTION_BOUNDARY / BITS_PER_UNIT);
+	}
     }
   else if (type_code == VOID_TYPE || type_code == ERROR_MARK)
     {
@@ -6670,6 +6683,36 @@ handle_section_attribute (tree *node, tree ARG_UNUSED (name), tree args,
   return NULL_TREE;
 }
 
+/* Check whether ALIGN is a valid user-specified alignment.  If so,
+   return its base-2 log; if not, output an error and return -1.  If
+   ALLOW_ZERO then 0 is valid and should result in a return of -1 with
+   no error.  */
+int
+check_user_alignment (const_tree align, bool allow_zero)
+{
+  int i;
+
+  if (!INTEGRAL_TYPE_P (TREE_TYPE (align))
+      || TREE_CODE (align) != INTEGER_CST)
+    {
+      error ("requested alignment is not an integer constant");
+      return -1;
+    }
+  else if (allow_zero && integer_zerop (align))
+    return -1;
+  else if ((i = tree_log2 (align)) == -1)
+    {
+      error ("requested alignment is not a power of 2");
+      return -1;
+    }
+  else if (i >= HOST_BITS_PER_INT - BITS_PER_UNIT_LOG)
+    {
+      error ("requested alignment is too large");
+      return -1;
+    }
+  return i;
+}
+
 /* Handle a "aligned" attribute; arguments as in
    struct attribute_spec.handler.  */
 
@@ -6693,21 +6736,8 @@ handle_aligned_attribute (tree *node, tree ARG_UNUSED (name), tree args,
   else if (TYPE_P (*node))
     type = node, is_type = 1;
 
-  if (TREE_CODE (align_expr) != INTEGER_CST)
-    {
-      error ("requested alignment is not a constant");
-      *no_add_attrs = true;
-    }
-  else if ((i = tree_log2 (align_expr)) == -1)
-    {
-      error ("requested alignment is not a power of 2");
-      *no_add_attrs = true;
-    }
-  else if (i >= HOST_BITS_PER_INT - BITS_PER_UNIT_LOG)
-    {
-      error ("requested alignment is too large");
-      *no_add_attrs = true;
-    }
+  if ((i = check_user_alignment (align_expr, false)) == -1)
+    *no_add_attrs = true;
   else if (is_type)
     {
       if ((flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
diff --git a/gcc/c-family/c-common.h b/gcc/c-family/c-common.h
index 7ecb57e5867..bff6956cc14 100644
--- a/gcc/c-family/c-common.h
+++ b/gcc/c-family/c-common.h
@@ -106,6 +106,9 @@ enum rid
   RID_DFLOAT32, RID_DFLOAT64, RID_DFLOAT128,
   RID_FRACT, RID_ACCUM,
 
+  /* C1X */
+  RID_ALIGNAS,
+
   /* This means to warn that this is a C++ keyword, and then treat it
      as a normal identifier.  */
   RID_CXX_COMPAT_WARN,
@@ -724,6 +727,7 @@ extern void finish_fname_decls (void);
 extern const char *fname_as_string (int);
 extern tree fname_decl (location_t, unsigned, tree);
 
+extern int check_user_alignment (const_tree, bool);
 extern void check_function_arguments (const_tree, int, tree *);
 extern void check_function_arguments_recurse (void (*)
 					      (void *, tree,