Re: [PATCH V3][gcc] libgccjit: introduce version entry points

[Andrea Corallo <andrea.corallo@arm.com>]

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Hi all,

Updated version of the patch mainly addressing comments on the
concurrency issues.

I came to the conclusions that the caching should be done in the
function that we decide to be thread safe.  However I haven't touched
parse_basever in any direction in the hope of having this still in
stage4.  As result I've mostly applied the mutex solution.

'make check-jit' runs clean

Bests

  Andrea

gcc/jit/ChangeLog
2020-??-??  Andrea Corallo  <andrea.corallo@arm.com>
	    David Malcolm  <dmalcolm@redhat.com>

	* docs/topics/compatibility.rst (LIBGCCJIT_ABI_13): New ABI tag
	plus add version paragraph.
	* libgccjit++.h (namespace gccjit::version): Add new namespace.
	* libgccjit.c (gcc_jit_version_major, gcc_jit_version_minor)
	(gcc_jit_version_patchlevel): New functions.
	* libgccjit.h (LIBGCCJIT_HAVE_gcc_jit_version): New macro.
	(gcc_jit_version_major, gcc_jit_version_minor)
	(gcc_jit_version_patchlevel): New functions.
	* libgccjit.map (LIBGCCJIT_ABI_13) New ABI tag.

gcc/testsuite/ChangeLog
2020-??-??  Andrea Corallo  <andrea.corallo@arm.com>

	* jit.dg/test-version.c: New testcase.
	* jit.dg/all-non-failing-tests.h: Add test-version.c.

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From ad86baf8472c6684aed9b62652922a83e147952a Mon Sep 17 00:00:00 2001
From: AndreaCorallo <andrea.corallo@arm.com>
Date: Sun, 8 Mar 2020 13:46:33 +0000
Subject: [PATCH] Add new version entry point

---
 gcc/jit/docs/topics/compatibility.rst        | 33 ++++++++++++++
 gcc/jit/libgccjit++.h                        | 22 ++++++++++
 gcc/jit/libgccjit.c                          | 46 ++++++++++++++++++++
 gcc/jit/libgccjit.h                          | 16 +++++++
 gcc/jit/libgccjit.map                        |  9 +++-
 gcc/testsuite/jit.dg/all-non-failing-tests.h |  7 +++
 gcc/testsuite/jit.dg/test-version.c          | 26 +++++++++++
 7 files changed, 158 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/jit.dg/test-version.c

diff --git a/gcc/jit/docs/topics/compatibility.rst b/gcc/jit/docs/topics/compatibility.rst
index a6faee0810e..0c0ce070d72 100644
--- a/gcc/jit/docs/topics/compatibility.rst
+++ b/gcc/jit/docs/topics/compatibility.rst
@@ -61,6 +61,28 @@ You can see the symbol tags provided by libgccjit.so using ``objdump``:
            LIBGCCJIT_ABI_0
    [...snip...]
 
+Programmatically checking version
+***************
+
+Client code can programmatically check libgccjit version using:
+
+.. function::  int gcc_jit_version_major (void)
+
+   Return libgccjit major version.  This is analogous to __GNUC__ in C code.
+
+.. function::  int gcc_jit_version_minor (void)
+
+   Return libgccjit minor version.  This is analogous to
+   __GNUC_MINOR__ in C code.
+
+.. function::  int gcc_jit_version_patchlevel (void)
+
+   Return libgccjit patchlevel version.  This is analogous to
+   __GNUC_PATCHLEVEL__ in C code.
+
+.. note:: These entry points has been added with ``LIBGCCJIT_ABI_13``
+          (see below).
+
 ABI symbol tags
 ***************
 
@@ -182,3 +204,14 @@ entrypoints:
 --------------------
 ``LIBGCCJIT_ABI_12`` covers the addition of
 :func:`gcc_jit_context_new_bitfield`
+
+``LIBGCCJIT_ABI_13``
+--------------------
+``LIBGCCJIT_ABI_13`` covers the addition of version functions via API
+entrypoints:
+
+  * :func:`gcc_jit_version_major`
+
+  * :func:`gcc_jit_version_minor`
+
+  * :func:`gcc_jit_version_patchlevel`
diff --git a/gcc/jit/libgccjit++.h b/gcc/jit/libgccjit++.h
index 82a62d614c5..69e67766640 100644
--- a/gcc/jit/libgccjit++.h
+++ b/gcc/jit/libgccjit++.h
@@ -49,6 +49,8 @@ namespace gccjit
   class timer;
   class auto_time;
 
+  namespace version {};
+
   /* Errors within the API become C++ exceptions of this class.  */
   class error
   {
@@ -1913,6 +1915,26 @@ auto_time::~auto_time ()
   m_timer.pop (m_item_name);
 }
 
+namespace version
+{
+inline int
+major_v ()
+{
+  return gcc_jit_version_major ();
+}
+
+inline int
+minor_v ()
+{
+  return gcc_jit_version_minor ();
+}
+
+inline int
+patchlevel_v ()
+{
+  return gcc_jit_version_patchlevel ();
+}
+} // namespace version
 } // namespace gccjit
 
 #endif /* #ifndef LIBGCCJIT_PLUS_PLUS_H */
diff --git a/gcc/jit/libgccjit.h b/gcc/jit/libgccjit.h
index 21a0dc09b03..1c5a12e9c01 100644
--- a/gcc/jit/libgccjit.h
+++ b/gcc/jit/libgccjit.h
@@ -1487,6 +1487,22 @@ gcc_jit_context_new_rvalue_from_vector (gcc_jit_context *ctxt,
 					size_t num_elements,
 					gcc_jit_rvalue **elements);
 
+#define LIBGCCJIT_HAVE_gcc_jit_version
+
+/* Functions to retrive libgccjit version.
+   Analogous to __GNUC__, __GNUC_MINOR__, __GNUC_PATCHLEVEL__ in C code.
+
+   These API entrypoints were added in LIBGCCJIT_ABI_13; you can test for their
+   presence using
+     #ifdef LIBGCCJIT_HAVE_gcc_jit_version
+ */
+extern int
+gcc_jit_version_major (void);
+extern int
+gcc_jit_version_minor (void);
+extern int
+gcc_jit_version_patchlevel (void);
+
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */
diff --git a/gcc/jit/libgccjit.c b/gcc/jit/libgccjit.c
index 83055fc297b..a29e9885e59 100644
--- a/gcc/jit/libgccjit.c
+++ b/gcc/jit/libgccjit.c
@@ -23,6 +23,8 @@ along with GCC; see the file COPYING3.  If not see
 #include "coretypes.h"
 #include "timevar.h"
 #include "typed-splay-tree.h"
+#include "cppbuiltin.h"
+#include <pthread.h>
 
 #include "libgccjit.h"
 #include "jit-recording.h"
@@ -3175,3 +3177,47 @@ gcc_jit_context_new_rvalue_from_vector (gcc_jit_context *ctxt,
      as_vec_type,
      (gcc::jit::recording::rvalue **)elements);
 }
+
+/* A mutex around the cached state in parse_basever.
+   Ideally this would be within parse_basever, but the mutex is only needed
+   by libgccjit.  */
+
+static pthread_mutex_t version_mutex = PTHREAD_MUTEX_INITIALIZER;
+
+struct version_info
+{
+  /* Default constructor.  Populate via parse_basever,
+     guarded by version_mutex.  */
+  version_info ()
+  {
+    pthread_mutex_lock (&version_mutex);
+    parse_basever (&major, &minor, &patchlevel);
+    pthread_mutex_unlock (&version_mutex);
+  }
+
+  int major;
+  int minor;
+  int patchlevel;
+};
+
+
+extern int
+gcc_jit_version_major (void)
+{
+  version_info vi;
+  return vi.major;
+}
+
+extern int
+gcc_jit_version_minor (void)
+{
+  version_info vi;
+  return vi.minor;
+}
+
+extern int
+gcc_jit_version_patchlevel (void)
+{
+  version_info vi;
+  return vi.patchlevel;
+}
diff --git a/gcc/jit/libgccjit.map b/gcc/jit/libgccjit.map
index 4514bd3aa33..6137dd4b4b0 100644
--- a/gcc/jit/libgccjit.map
+++ b/gcc/jit/libgccjit.map
@@ -179,4 +179,11 @@ LIBGCCJIT_ABI_11 {
 LIBGCCJIT_ABI_12 {
   global:
     gcc_jit_context_new_bitfield;
-} LIBGCCJIT_ABI_11;
\ No newline at end of file
+} LIBGCCJIT_ABI_11;
+
+LIBGCCJIT_ABI_13 {
+  global:
+    gcc_jit_version_major;
+    gcc_jit_version_minor;
+    gcc_jit_version_patchlevel;
+} LIBGCCJIT_ABI_12;
\ No newline at end of file
diff --git a/gcc/testsuite/jit.dg/all-non-failing-tests.h b/gcc/testsuite/jit.dg/all-non-failing-tests.h
index 0272e6f846f..cba4ac51cc9 100644
--- a/gcc/testsuite/jit.dg/all-non-failing-tests.h
+++ b/gcc/testsuite/jit.dg/all-non-failing-tests.h
@@ -8,6 +8,13 @@
    hooks provided by each test case.  */
 #define COMBINED_TEST
 
+/* test-version.c */
+#define create_code create_code_version
+#define verify_code verify_code_version
+#include "test-version.c"
+#undef create_code
+#undef verify_code
+
 /* test-accessing-bitfield.c */
 #define create_code create_code_accessing_bitfield
 #define verify_code verify_code_accessing_bitfield
diff --git a/gcc/testsuite/jit.dg/test-version.c b/gcc/testsuite/jit.dg/test-version.c
new file mode 100644
index 00000000000..4338a00018b
--- /dev/null
+++ b/gcc/testsuite/jit.dg/test-version.c
@@ -0,0 +1,26 @@
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "libgccjit.h"
+
+#include "harness.h"
+
+#ifndef LIBGCCJIT_HAVE_gcc_jit_version
+#error LIBGCCJIT_HAVE_gcc_jit_version was not defined
+#endif
+
+void
+create_code (gcc_jit_context *ctxt, void *user_data)
+{
+  /* Do nothing.  */
+}
+
+void
+verify_code (gcc_jit_context *ctxt, gcc_jit_result *result)
+{
+  if (!gcc_jit_version_major ())
+    fail ("Major version is zero");
+  /* Minor and patchlevel can be zero.  */
+  gcc_jit_version_minor ();
+  gcc_jit_version_patchlevel ();
+}
-- 
2.17.1