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* [PATCH 1/2] testsuite: Add and use thread_fence effective-target
@ 2023-09-10 19:30 Christophe Lyon
  2023-09-10 19:30 ` [PATCH 2/2] libstdc++: Add dg-require-thread-fence in several tests Christophe Lyon
  0 siblings, 1 reply; 16+ messages in thread
From: Christophe Lyon @ 2023-09-10 19:30 UTC (permalink / raw)
  To: gcc-patches, jwakely, libstdc++, kyrylo.tkachov, richard.earnshaw
  Cc: Christophe Lyon

Some targets like arm-eabi with newlib and default settings rely on
__sync_synchronize() to ensure synchronization.  Newlib does not
implement it by default, to make users aware they have to take special
care.

This makes a few tests fail to link.

This patch adds a new thread_fence effective target (similar to the
corresponding one in libstdc++ testsuite), and uses it in the tests
that need it, making them UNSUPPORTED instead of FAIL and UNRESOLVED.

2023-09-10  Christophe Lyon  <christophe.lyon@linaro.org>

	gcc/
	* doc/sourcebuild.texi (Other attributes): Document thread_fence
	effective-target.

	gcc/testsuite/
	* g++.dg/init/array54.C: Require thread_fence.
	* gcc.dg/c2x-nullptr-1.c: Likewise.
	* gcc.dg/pr103721-2.c: Likewise.
	* lib/target-supports.exp (check_effective_target_thread_fence):
	New.
---
 gcc/doc/sourcebuild.texi              |  4 ++++
 gcc/testsuite/g++.dg/init/array54.C   |  1 +
 gcc/testsuite/gcc.dg/c2x-nullptr-1.c  |  1 +
 gcc/testsuite/gcc.dg/pr103721-2.c     |  1 +
 gcc/testsuite/lib/target-supports.exp | 12 ++++++++++++
 5 files changed, 19 insertions(+)

diff --git a/gcc/doc/sourcebuild.texi b/gcc/doc/sourcebuild.texi
index 1a78b3c1abb..a5f61c29f3b 100644
--- a/gcc/doc/sourcebuild.texi
+++ b/gcc/doc/sourcebuild.texi
@@ -2860,6 +2860,10 @@ Compiler has been configured to support link-time optimization (LTO).
 Compiler and linker support link-time optimization relocatable linking
 with @option{-r} and @option{-flto} options.
 
+@item thread_fence
+Target implements @code{__atomic_thread_fence} without relying on
+non-implemented @code{__sync_synchronize()}.
+
 @item naked_functions
 Target supports the @code{naked} function attribute.
 
diff --git a/gcc/testsuite/g++.dg/init/array54.C b/gcc/testsuite/g++.dg/init/array54.C
index f6be350ba72..5241e451d6d 100644
--- a/gcc/testsuite/g++.dg/init/array54.C
+++ b/gcc/testsuite/g++.dg/init/array54.C
@@ -1,5 +1,6 @@
 // PR c++/90947
 // { dg-do run { target c++11 } }
+// { dg-require-effective-target thread_fence }
 
 #include <atomic>
 
diff --git a/gcc/testsuite/gcc.dg/c2x-nullptr-1.c b/gcc/testsuite/gcc.dg/c2x-nullptr-1.c
index 4e440234d52..97a31c27409 100644
--- a/gcc/testsuite/gcc.dg/c2x-nullptr-1.c
+++ b/gcc/testsuite/gcc.dg/c2x-nullptr-1.c
@@ -1,5 +1,6 @@
 /* Test valid usage of C23 nullptr.  */
 /* { dg-do run } */
+// { dg-require-effective-target thread_fence }
 /* { dg-options "-std=c2x -pedantic-errors -Wall -Wextra -Wno-unused-variable" } */
 
 #include <stdarg.h>
diff --git a/gcc/testsuite/gcc.dg/pr103721-2.c b/gcc/testsuite/gcc.dg/pr103721-2.c
index aefa1f0f147..e059b1cfc2d 100644
--- a/gcc/testsuite/gcc.dg/pr103721-2.c
+++ b/gcc/testsuite/gcc.dg/pr103721-2.c
@@ -1,4 +1,5 @@
 // { dg-do run }
+// { dg-require-effective-target thread_fence }
 // { dg-options "-O2" }
 
 extern void abort ();
diff --git a/gcc/testsuite/lib/target-supports.exp b/gcc/testsuite/lib/target-supports.exp
index d353cc0aaf0..7ac9e7530cc 100644
--- a/gcc/testsuite/lib/target-supports.exp
+++ b/gcc/testsuite/lib/target-supports.exp
@@ -9107,6 +9107,18 @@ proc check_effective_target_sync_char_short { } {
 	     || [check_effective_target_mips_llsc] }}]
 }
 
+# Return 1 if thread_fence does not rely on __sync_synchronize
+# library function
+
+proc check_effective_target_thread_fence {} {
+    return [check_no_compiler_messages thread_fence executable {
+	int main () {
+	    __atomic_thread_fence (__ATOMIC_SEQ_CST);
+	    return 0;
+	}
+    } ""]
+}
+
 # Return 1 if the target uses a ColdFire FPU.
 
 proc check_effective_target_coldfire_fpu { } {
-- 
2.34.1


^ permalink raw reply	[flat|nested] 16+ messages in thread
end of thread, other threads:[~2023-09-14  9:25 UTC | newest]

Thread overview: 16+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-09-10 19:30 [PATCH 1/2] testsuite: Add and use thread_fence effective-target Christophe Lyon
2023-09-10 19:30 ` [PATCH 2/2] libstdc++: Add dg-require-thread-fence in several tests Christophe Lyon
2023-09-11 10:59   ` Jonathan Wakely
2023-09-11 12:36     ` Christophe Lyon
2023-09-11 13:10       ` Jonathan Wakely
2023-09-11 13:57         ` Christophe Lyon
2023-09-11 15:22           ` Jonathan Wakely
2023-09-11 15:27             ` Richard Earnshaw (lists)
2023-09-11 15:39             ` Christophe Lyon
2023-09-11 16:11               ` Jonathan Wakely
2023-09-12  7:59                 ` Christophe Lyon
2023-09-12  9:07                   ` Jonathan Wakely
2023-09-13 15:37                     ` Christophe Lyon
2023-09-13 15:56                       ` Jonathan Wakely
2023-09-14  9:09                         ` [PATCH v2 " Christophe Lyon
2023-09-14  9:25                           ` Jonathan Wakely

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