Hi,
DEC-C, the DEC compiler provided on VMS, has added to ANSI-C at least one
extension that is difficult to work-around as it is used in the system headers:
varargs without named argument. It makes sense on VMS because of its ABI which
pass the number of arguments used.
This patch allows such declaration when the new flag -fdecc-extensions is used
(C and ObjC only as C++ already allows that).
I use the plural for consistency with other -fxxx-extensions and in case where
others extensions are added.
Bootstrapped on x86_64-darwin, no regressions.
Ok for mainline ?
Tristan.
gcc/
2011-09-29 Tristan Gingold <ging...@adacore.com>
* doc/invoke.texi: Document -fdecc-extensions.
* c-parser.c (c_parser_parms_list_declarator): Handle -fdecc-extensions.
gcc/c-family/
2011-09-29 Tristan Gingold <ging...@adacore.com>
* c.opt (fdecc-extensions): New.
gcc/testsuite/
2011-09-29 Tristan Gingold <ging...@adacore.com>
* gcc.dg/va-arg-4.c: New test.
* gcc.dg/va-arg-5.c: Ditto.
diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
index e6ac5dc..4879cff 100644
--- a/gcc/c-family/c.opt
+++ b/gcc/c-family/c.opt
@@ -739,6 +739,10 @@ fconstexpr-depth=
C++ ObjC++ Joined RejectNegative UInteger Var(max_constexpr_depth) Init(512)
-fconstexpr-depth=<number> Specify maximum constexpr recursion depth
+fdecc-extensions
+C ObjC Var(flag_decc_extensions)
+Enable DEC-C language extensions
+
fdeduce-init-list
C++ ObjC++ Var(flag_deduce_init_list) Init(1)
-fno-deduce-init-list disable deduction of std::initializer_list for a
template type parameter from a brace-enclosed initializer-list
diff --git a/gcc/c-parser.c b/gcc/c-parser.c
index ff376df..788d13c 100644
--- a/gcc/c-parser.c
+++ b/gcc/c-parser.c
@@ -3159,10 +3159,19 @@ c_parser_parms_list_declarator (c_parser *parser, tree
attrs, tree expr)
if (c_parser_next_token_is (parser, CPP_ELLIPSIS))
{
struct c_arg_info *ret = build_arg_info ();
- /* Suppress -Wold-style-definition for this case. */
- ret->types = error_mark_node;
- error_at (c_parser_peek_token (parser)->location,
- "ISO C requires a named argument before %<...%>");
+
+ if (flag_decc_extensions)
+ {
+ /* F (...) is allowed by DEC-C. */
+ ret->types = NULL_TREE;
+ }
+ else
+ {
+ /* Suppress -Wold-style-definition for this case. */
+ ret->types = error_mark_node;
+ error_at (c_parser_peek_token (parser)->location,
+ "ISO C requires a named argument before %<...%>");
+ }
c_parser_consume_token (parser);
if (c_parser_next_token_is (parser, CPP_CLOSE_PAREN))
{
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index e166964..1fceace 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -170,7 +170,7 @@ in the following sections.
@item C Language Options
@xref{C Dialect Options,,Options Controlling C Dialect}.
@gccoptlist{-ansi -std=@var{standard} -fgnu89-inline @gol
--aux-info @var{filename} @gol
+-aux-info @var{filename} -fdecc-extensions @gol
-fno-asm -fno-builtin -fno-builtin-@var{function} @gol
-fhosted -ffreestanding -fopenmp -fms-extensions -fplan9-extensions @gol
-trigraphs -no-integrated-cpp -traditional -traditional-cpp @gol
@@ -1733,6 +1733,16 @@ fields declared using a typedef. @xref{Unnamed
Fields,,Unnamed
struct/union fields within structs/unions}, for details. This is only
supported for C, not C++.
+@item -fdecc-extensions
+Accept some non-standard constructs used by DEC-C in VMS header files.
+
+This allows varargs functions without named argument. VMS is able to
+support this feature because of its call convention which pass the
+number of arguments in a register. Although it is possible to define
+such a function, this is not very usefull as it is not possible to read
+the arguments. This is only supported for C as this construct is
+allowed by C++.
+
@item -trigraphs
@opindex trigraphs
Support ISO C trigraphs. The @option{-ansi} option (and @option{-std}
diff --git a/gcc/testsuite/gcc.dg/va-arg-4.c b/gcc/testsuite/gcc.dg/va-arg-4.c
new file mode 100644
index 0000000..6d737c4
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/va-arg-4.c
@@ -0,0 +1,3 @@
+/* { dg-do compile } */
+#include <stdarg.h>
+extern void baz(...); /* { dg-error "requires a named argument" } */
diff --git a/gcc/testsuite/gcc.dg/va-arg-5.c b/gcc/testsuite/gcc.dg/va-arg-5.c
new file mode 100644
index 0000000..015f592
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/va-arg-5.c
@@ -0,0 +1,4 @@
+/* { dg-do compile } */
+/* { dg-options "-fdecc-extensions" } */
+#include <stdarg.h>
+extern void baz(...);
