error: undefined identifier '__builtin_va_arg_pack'

error: undefined identifier '__builtin_va_arg_pack'

[Jeff Layton]

I was running sparse on some code I maintain and saw a bunch of
warnings like this:

    /usr/include/bits/stdio2.h:98:25: error: undefined identifier '__builtin_va_arg_pack'
    /usr/include/bits/stdio2.h:98:25: error: not a function <noident>

It looks like gcc defines this in recent versions:

    http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html

It seems like something like this might do the trick for
__builtin_va_arg_pack_len:

-----------------[snip]------------------
diff --git a/lib.c b/lib.c
index 7e822eb..db981d8 100644
--- a/lib.c
+++ b/lib.c
@@ -779,6 +779,7 @@ void declare_builtin_functions(void)
 	add_pre_buffer("extern double __builtin_fabs(double);\n");
 	add_pre_buffer("extern void __sync_synchronize();\n");
 	add_pre_buffer("extern int __sync_bool_compare_and_swap(void *, ...);\n");
+	add_pre_buffer("extern size_t __builtin_va_arg_pack_len(void);\n");
 
 	/* Add Blackfin-specific stuff */
 	add_pre_buffer(
-----------------[snip]------------------

...but I'm unclear on how best to fix the errors around
__builtin_va_arg_pack since it doesn't seem to return a well-defined
type.

Thanks...
-- 
Jeff Layton <jlayton@redhat.com>

[PATCH] sparse: add __builtin_va_arg_pack() and __builtin_va_arg_pack_len()

[Jeff Layton]

this patch stops sparse from complaining about them not being defined:

    /usr/include/bits/stdio2.h:98:25: error: undefined identifier '__builtin_va_arg_pack'
    /usr/include/bits/stdio2.h:98:25: error: not a function <noident>

Probably, there is some better way to do this that actually validates
this function, but I'm not clear on how to do it.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
---
 lib.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib.c b/lib.c
index 7e822eb..3f687ae 100644
--- a/lib.c
+++ b/lib.c
@@ -777,6 +777,7 @@ void declare_builtin_functions(void)
 	add_pre_buffer("extern long __builtin_alpha_cmpbge(long, long);\n");
 	add_pre_buffer("extern long __builtin_labs(long);\n");
 	add_pre_buffer("extern double __builtin_fabs(double);\n");
+	add_pre_buffer("extern __SIZE_TYPE__ __builtin_va_arg_pack_len(void);\n");
 	add_pre_buffer("extern void __sync_synchronize();\n");
 	add_pre_buffer("extern int __sync_bool_compare_and_swap(void *, ...);\n");
 
@@ -876,6 +877,7 @@ void create_builtin_stream(void)
 	add_pre_buffer("#define __builtin_va_copy(dest, src) ({ dest = src; (void)0; })\n");
 	add_pre_buffer("#define __builtin_va_end(arg)\n");
 	add_pre_buffer("#define __builtin_ms_va_end(arg)\n");
+	add_pre_buffer("#define __builtin_va_arg_pack()\n");
 
 	/* FIXME! We need to do these as special magic macros at expansion time! */
 	add_pre_buffer("#define __BASE_FILE__ \"base_file.c\"\n");
-- 
1.8.3.1

Re: [PATCH] sparse: add __builtin_va_arg_pack() and __builtin_va_arg_pack_len()

[Christopher Li]

On Thu, Jul 18, 2013 at 8:36 AM, Jeff Layton <jlayton@redhat.com> wrote:
> this patch stops sparse from complaining about them not being defined:
>
>     /usr/include/bits/stdio2.h:98:25: error: undefined identifier '__builtin_va_arg_pack'
>     /usr/include/bits/stdio2.h:98:25: error: not a function <noident>
>
> Probably, there is some better way to do this that actually validates
> this function, but I'm not clear on how to do it.
>

Please add a test case for the typical usage case of __buildin_va_arg_pack()
and __builtin_va_arg_pack_len(). At the very least, it needs to cover the real
world breakage that bother you enough to submit a patch.

The patch looks good otherwise.

Thanks

Chris

[PATCH v2] sparse: add __builtin_va_arg_pack() and __builtin_va_arg_pack_len()

[Jeff Layton]

this patch stops sparse from complaining about them not being defined:

    /usr/include/bits/stdio2.h:98:25: error: undefined identifier '__builtin_va_arg_pack'
    /usr/include/bits/stdio2.h:98:25: error: not a function <noident>

Signed-off-by: Jeff Layton <jlayton@redhat.com>
---
 lib.c                            |  2 ++
 validation/builtin_va_arg_pack.c | 20 ++++++++++++++++++++
 2 files changed, 22 insertions(+)
 create mode 100644 validation/builtin_va_arg_pack.c

diff --git a/lib.c b/lib.c
index 7e822eb..3f687ae 100644
--- a/lib.c
+++ b/lib.c
@@ -777,6 +777,7 @@ void declare_builtin_functions(void)
 	add_pre_buffer("extern long __builtin_alpha_cmpbge(long, long);\n");
 	add_pre_buffer("extern long __builtin_labs(long);\n");
 	add_pre_buffer("extern double __builtin_fabs(double);\n");
+	add_pre_buffer("extern __SIZE_TYPE__ __builtin_va_arg_pack_len(void);\n");
 	add_pre_buffer("extern void __sync_synchronize();\n");
 	add_pre_buffer("extern int __sync_bool_compare_and_swap(void *, ...);\n");
 
@@ -876,6 +877,7 @@ void create_builtin_stream(void)
 	add_pre_buffer("#define __builtin_va_copy(dest, src) ({ dest = src; (void)0; })\n");
 	add_pre_buffer("#define __builtin_va_end(arg)\n");
 	add_pre_buffer("#define __builtin_ms_va_end(arg)\n");
+	add_pre_buffer("#define __builtin_va_arg_pack()\n");
 
 	/* FIXME! We need to do these as special magic macros at expansion time! */
 	add_pre_buffer("#define __BASE_FILE__ \"base_file.c\"\n");
diff --git a/validation/builtin_va_arg_pack.c b/validation/builtin_va_arg_pack.c
new file mode 100644
index 0000000..3426b86
--- /dev/null
+++ b/validation/builtin_va_arg_pack.c
@@ -0,0 +1,20 @@
+extern void v(int a, ...);
+
+extern inline __attribute__((__always_inline__)) void f(int a, ...)
+{
+	__SIZE_TYPE__ b = __builtin_va_arg_pack_len();
+}
+
+extern inline __attribute__((__always_inline__)) void g(int a, ...)
+{
+	v(a, __builtin_va_arg_pack());
+}
+
+static void h(void)
+{
+	f(0, 0);
+	g(0, 0);
+}
+/*
+ * check-name: __builtin_va_arg_pack()
+ */
-- 
1.8.3.1

Re: [PATCH v2] sparse: add __builtin_va_arg_pack() and __builtin_va_arg_pack_len()

[Christopher Li]

On Fri, Jul 19, 2013 at 3:33 AM, Jeff Layton <jlayton@redhat.com> wrote:
> this patch stops sparse from complaining about them not being defined:
>
>     /usr/include/bits/stdio2.h:98:25: error: undefined identifier '__builtin_va_arg_pack'
>     /usr/include/bits/stdio2.h:98:25: error: not a function <noident>
>
> Signed-off-by: Jeff Layton <jlayton@redhat.com>

Looks good, will apply.

Chris