Hi Jonathan,
Thank you for the suggestion. I have just attached the updated the
patch. It works as before.
Is this Okay to commit?
Regards,
Renlin Li
On 22/04/15 11:19, Jonathan Wakely wrote:
On 21/04/15 15:29 +0100, Renlin Li wrote:
Hi all,
This patch defines a new dg-require-thread-fence directive. And three
test cases are updated to use it.
The new directive are used to check whether the target support thread
fence either by the target back-end or external library function call.
A thread fence is required to expand atomic load/store.
There is a case that a call to some external __sync_synchronize will
be emitted, and it's not implemented. You will get linking errors like
this: undefined reference to `__sync_synchronize`. Test cases which
are gated by this directive will be skipped if no thread fence is
available. For example the three test cases updated here. They fail on
arm-none-eabi target where __sync_synchronize() isn't implemented and
target cpu has no memory_barrier.
___sync_synchronize () is used to check whether thread-fence is
available. In GCC sync_synchronize is expanded as
expand_mem_thread_fence (MEMMODEL_SEQ_CST).
I don't like making the directive depend directly on the legacy
__sync_synchronize function, because that function is not required on
most targets, AFAICT it's only needed for ARM and MIPS.
Could you make the directive check
__atomic_thread_fence(__ATOMIC_SEQ_CST) instead? I think that will
still expand to __sync_synchronize() for ARM, so should still test the
same thing, but that way we aren't adding a dependency on
__sync_synchronize for all targets.
diff --git a/libstdc++-v3/testsuite/29_atomics/atomic_flag/clear/1.cc b/libstdc++-v3/testsuite/29_atomics/atomic_flag/clear/1.cc
index 0a4219c..a6e2299 100644
--- a/libstdc++-v3/testsuite/29_atomics/atomic_flag/clear/1.cc
+++ b/libstdc++-v3/testsuite/29_atomics/atomic_flag/clear/1.cc
@@ -1,4 +1,5 @@
// { dg-options "-std=gnu++11" }
+// { dg-require-thread-fence "" }
// Copyright (C) 2009-2015 Free Software Foundation, Inc.
//
diff --git a/libstdc++-v3/testsuite/29_atomics/atomic_flag/test_and_set/explicit.cc b/libstdc++-v3/testsuite/29_atomics/atomic_flag/test_and_set/explicit.cc
index 2ff740b..0655be4 100644
--- a/libstdc++-v3/testsuite/29_atomics/atomic_flag/test_and_set/explicit.cc
+++ b/libstdc++-v3/testsuite/29_atomics/atomic_flag/test_and_set/explicit.cc
@@ -1,4 +1,5 @@
// { dg-options "-std=gnu++11" }
+// { dg-require-thread-fence "" }
// Copyright (C) 2008-2015 Free Software Foundation, Inc.
//
diff --git a/libstdc++-v3/testsuite/29_atomics/atomic_flag/test_and_set/implicit.cc b/libstdc++-v3/testsuite/29_atomics/atomic_flag/test_and_set/implicit.cc
index 6ac20c0..a867da2 100644
--- a/libstdc++-v3/testsuite/29_atomics/atomic_flag/test_and_set/implicit.cc
+++ b/libstdc++-v3/testsuite/29_atomics/atomic_flag/test_and_set/implicit.cc
@@ -1,4 +1,5 @@
// { dg-options "-std=gnu++11" }
+// { dg-require-thread-fence "" }
// Copyright (C) 2008-2015 Free Software Foundation, Inc.
//
diff --git a/libstdc++-v3/testsuite/lib/dg-options.exp b/libstdc++-v3/testsuite/lib/dg-options.exp
index 38c8206..56ca896 100644
--- a/libstdc++-v3/testsuite/lib/dg-options.exp
+++ b/libstdc++-v3/testsuite/lib/dg-options.exp
@@ -115,6 +115,15 @@ proc dg-require-cmath { args } {
return
}
+proc dg-require-thread-fence { args } {
+ if { ![ check_v3_target_thread_fence ] } {
+ upvar dg-do-what dg-do-what
+ set dg-do-what [list [lindex ${dg-do-what} 0] "N" "P"]
+ return
+ }
+ return
+}
+
proc dg-require-atomic-builtins { args } {
if { ![ check_v3_target_atomic_builtins ] } {
upvar dg-do-what dg-do-what
diff --git a/libstdc++-v3/testsuite/lib/libstdc++.exp b/libstdc++-v3/testsuite/lib/libstdc++.exp
index b2f7d00..9e395e2 100644
--- a/libstdc++-v3/testsuite/lib/libstdc++.exp
+++ b/libstdc++-v3/testsuite/lib/libstdc++.exp
@@ -1221,6 +1221,62 @@ proc check_v3_target_cmath { } {
return $et_c99_math
}
+proc check_v3_target_thread_fence { } {
+ global cxxflags
+ global DEFAULT_CXXFLAGS
+ global et_thread_fence
+
+ global tool
+
+ if { ![info exists et_thread_fence_target_name] } {
+ set et_thread_fence_target_name ""
+ }
+
+ # If the target has changed since we set the cached value, clear it.
+ set current_target [current_target_name]
+ if { $current_target != $et_thread_fence_target_name } {
+ verbose "check_v3_target_thread_fence: `$et_thread_fence_target_name'" 2
+ set et_thread_fence_target_name $current_target
+ if [info exists et_thread_fence] {
+ verbose "check_v3_target_thread_fence: removing cached result" 2
+ unset et_thread_fence
+ }
+ }
+
+ if [info exists et_thread_fence] {
+ verbose "check_v3_target_thread_fence: using cached result" 2
+ } else {
+ set et_thread_fence 0
+
+ # Set up and preprocess a C++11 test program that depends
+ # on the thread fence to be available.
+ set src thread_fence[pid].cc
+
+ set f [open $src "w"]
+ puts $f "int main() {"
+ puts $f "__atomic_thread_fence (__ATOMIC_SEQ_CST);"
+ puts $f "return 0;"
+ puts $f "}"
+ close $f
+
+ set cxxflags_saved $cxxflags
+ set cxxflags "$cxxflags $DEFAULT_CXXFLAGS -Werror -std=gnu++11"
+
+ set lines [v3_target_compile $src /dev/null executable ""]
+ set cxxflags $cxxflags_saved
+ file delete $src
+
+ if [string match "" $lines] {
+ # No error message, linking succeeded.
+ set et_thread_fence 1
+ } else {
+ verbose "check_v3_target_thread_fence: compilation failed" 2
+ }
+ }
+ verbose "check_v3_target_thread_fence: $et_thread_fence" 2
+ return $et_thread_fence
+}
+
proc check_v3_target_atomic_builtins { } {
global cxxflags
global DEFAULT_CXXFLAGS
