Hello All,
As I explained in https://gcc.gnu.org/ml/jit/2016-q2/msg00042.html it is
difficult (or tricky without using dirty tricks involving the GCC plugin
headers) to use GCCJIT to emit code equivalent to the following C file:
extern int a;
int get_atomic_a (void) {
return __atomic_load_n (&a, __ATOMIC_SEQ_CST);
}
The issue is that __ATOMIC_SEQ_CST is a magic preprocessor (but non-standard!)
symbol which might not be available
(or might have a different value) in the C code for GCCJIT building such an AST.
So we need a function to retrieve some magic integral value from the GCCJIT
compiler.
The attached patch (relative to trunk svn 236583) is a first attempt to solve
that issue
(and also give ability to query some other magic numbers).
Proposed ChangeLog entry (in gcc/jit/)
2016-05-23 Basile Starynkevitch <bas...@starynkevitch.net>
* libgccjit.h (LIBGCCJIT_HAVE_gcc_jit_magic_int): New macro.
(gcc_jit_magic_int): New public function declaration.
* libgccjit.c: Include "cppbuiltin.h", "options.h", "flag-types.h"
(gcc_jit_magic_int): New function.
* libgccjit.map: Add gcc_jit_magic_int to LIBGCCJIT_ABI_6.
Comments (or an ok to commit) are welcome. (I am not sure that
__SANITIZE_ADDRESS__ is correctly handled,
because I would believe that optimization flags are not globals in GCCJIT)
Regards.
--
Basile STARYNKEVITCH http://starynkevitch.net/Basile/
email: basile<at>starynkevitch<dot>net mobile: +33 6 8501 2359
8, rue de la Faiencerie, 92340 Bourg La Reine, France
*** opinions {are only mine, sont seulement les miennes} ***
Index: gcc/jit/libgccjit.h
===================================================================
--- gcc/jit/libgccjit.h (revision 236583)
+++ gcc/jit/libgccjit.h (working copy)
@@ -1387,6 +1387,27 @@
gcc_jit_rvalue_set_bool_require_tail_call (gcc_jit_rvalue *call,
int require_tail_call);
+
+ /* Magical integer values useful in the compiler; similar to
+ predefined C macros like __GNUC__, __GNUC_MINOR__,
+ __GNUC_PATCHLEVEL__, __ATOMIC_RELAXED, __ATOMIC_SEQ_CST,
+ __ATOMIC_ACQUIRE, __ATOMIC_RELEASE, __ATOMIC_ACQ_REL,
+ __ATOMIC_CONSUME, __PIC__, __PIE__, etc. Typical usage would be:
+
+ bool err=false;
+ int mypic = gcc_jit_magic_int("__PIC__", &err);
+ if (err) somethinggotwrong();
+
+ This function is expected to be rarely called, typically once at
+ initialization time.
+
+ This API entrypoint was added in LIBGCCJIT_ABI_6; you can test for its
+ presence using
+ #ifdef LIBGCCJIT_HAVE_gcc_jit_magic_int
+ */
+#define LIBGCCJIT_HAVE_gcc_jit_magic_int
+extern int gcc_jit_magic_int(const char*name, bool*errp);
+
#ifdef __cplusplus
}
#endif /* __cplusplus */
Index: gcc/jit/libgccjit.c
===================================================================
--- gcc/jit/libgccjit.c (revision 236583)
+++ gcc/jit/libgccjit.c (working copy)
@@ -23,6 +23,9 @@
#include "coretypes.h"
#include "timevar.h"
#include "typed-splay-tree.h"
+#include "cppbuiltin.h"
+#include "options.h"
+#include "flag-types.h"
#include "libgccjit.h"
#include "jit-recording.h"
@@ -2970,3 +2973,44 @@
call->set_require_tail_call (require_tail_call);
}
+
+
+/* Public entrypoint. See description in libgccjit.h. */
+
+int gcc_jit_magic_int(const char*name, bool*errp)
+{
+ static int major, minor, patchlevel;
+ if (!major) /* call once: */
+ parse_basever (&major, &minor, &patchlevel);
+
+ RETURN_VAL_IF_FAIL (name,
+ errp?((*errp=true),0):0,
+ NULL, NULL,
+ "NULL name");
+ RETURN_VAL_IF_FAIL (name[0] == '_' && name[1] == '_',
+ errp?((*errp=true),0):0,
+ NULL, NULL,
+ "name should start with two underscores");
+#define HAVE_MAGIC_INT(NamStr,Val) do { \
+ if (!strcmp(name, NamStr)) { \
+ if (errp) *errp = false; \
+ return Val; }} while(0)
+ // keep these in alphabetical order...
+ HAVE_MAGIC_INT("__ATOMIC_ACQUIRE", MEMMODEL_ACQUIRE);
+ HAVE_MAGIC_INT("__ATOMIC_ACQ_REL", MEMMODEL_ACQ_REL);
+ HAVE_MAGIC_INT("__ATOMIC_CONSUME", MEMMODEL_CONSUME);
+ HAVE_MAGIC_INT("__ATOMIC_RELAXED", MEMMODEL_RELAXED);
+ HAVE_MAGIC_INT("__ATOMIC_RELEASE", MEMMODEL_RELEASE);
+ HAVE_MAGIC_INT("__ATOMIC_SEQ_CST", MEMMODEL_SEQ_CST);
+ HAVE_MAGIC_INT("__GNUC_MINOR__", minor);
+ HAVE_MAGIC_INT("__GNUC_PATCHLEVEL__", patchlevel);
+ HAVE_MAGIC_INT("__GNUC__", major);
+ HAVE_MAGIC_INT("__PIC__", flag_pic);
+ HAVE_MAGIC_INT("__PIE__", flag_pie);
+ HAVE_MAGIC_INT("__SANITIZE_ADDRESS__", flag_sanitize & SANITIZE_ADDRESS);
+ HAVE_MAGIC_INT("__SANITIZE_THREAD__", flag_sanitize & SANITIZE_THREAD);
+#undef HAVE_MAGIC_INT
+ RETURN_VAL_IF_FAIL_PRINTF1 (false, errp?((*errp=true),0):0,
+ NULL, NULL,
+ "unknown magic int name: %s", name);
+}
Index: gcc/jit/libgccjit.map
===================================================================
--- gcc/jit/libgccjit.map (revision 236583)
+++ gcc/jit/libgccjit.map (working copy)
@@ -149,4 +149,5 @@
LIBGCCJIT_ABI_6 {
global:
gcc_jit_rvalue_set_bool_require_tail_call;
+ gcc_jit_magic_int;
} LIBGCCJIT_ABI_5;
