[uclibc-ng-devel] [RFC PATCH] libpthread/nptl: Use arch-dependent unwind-forcedunwind.c if available

Ignacy Gawędzki ignacy.gawedzki at green-communications.fr
Tue Sep 27 22:11:12 CEST 2016


Using unwind-forcedunwind.c from nptl/sysdeps/pthread doesn't work
well on ARM, see
nptl/sysdeps/unix/sysv/linux/arm/unwind-forcedunwind.c for an
explanation.

The following code example shows what's wrong without the ARM-specific
version.

--------------------------------------------------------------------

struct Foo {
  ~Foo();
};

Foo::~Foo() {}

void f()
{
  Foo	a;
  throw 0;
}

int main()
{
  try {
    f();
  } catch (int) {
    std::cerr << "caught" << std::endl;
  }
  return 0;
}
--------------------------------------------------------------------

Compile without any optimizations (it's important that Foo's
destructor is not inlined) and link with -lpthread.  The thrown
exception is not caught as expected and the program aborts.

Signed-off-by: Ignacy Gawędzki <ignacy.gawedzki at green-communications.fr>
---
 libpthread/nptl/sysdeps/pthread/Makefile.in                   | 4 ++--
 libpthread/nptl/sysdeps/pthread/pthread-unwind-forcedunwind.c | 1 +
 2 files changed, 3 insertions(+), 2 deletions(-)
 create mode 100644 libpthread/nptl/sysdeps/pthread/pthread-unwind-forcedunwind.c

diff --git a/libpthread/nptl/sysdeps/pthread/Makefile.in b/libpthread/nptl/sysdeps/pthread/Makefile.in
index 9d99f31..6325c0d 100644
--- a/libpthread/nptl/sysdeps/pthread/Makefile.in
+++ b/libpthread/nptl/sysdeps/pthread/Makefile.in
@@ -40,7 +40,7 @@ CFLAGS-pthread_barrier_wait.c = -D_GNU_SOURCE
 CFLAGS-pthread_spin_destroy.c = -D_GNU_SOURCE
 CFLAGS-pthread_spin_init.c = -D_GNU_SOURCE
 CFLAGS-pthread_spin_unlock.c = -D_GNU_SOURCE
-CFLAGS-unwind-forcedunwind.c = -fexceptions -fasynchronous-unwind-tables
+CFLAGS-pthread-unwind-forcedunwind.c = -fexceptions -fasynchronous-unwind-tables
 
 CFLAGS-OMIT-librt-cancellation.c = -DIS_IN_libpthread
 CFLAGS-OMIT-rt-unwind-resume.c = -DIS_IN_libpthread
@@ -49,7 +49,7 @@ CFLAGS-librt-cancellation.c = -DIS_IN_librt				\
 CFLAGS-rt-unwind-resume.c = -DIS_IN_librt				\
 			    -fexceptions -fasynchronous-unwind-tables
 
-libpthread-so-y += $(patsubst %,$(libpthread_pthread_OUT)/%.oS, unwind-forcedunwind)
+libpthread-so-y += $(patsubst %,$(libpthread_pthread_OUT)/%.oS, pthread-unwind-forcedunwind)
 
 librt-pt-routines-y = librt-cancellation.c
 librt-pt-shared-only-routines-y = rt-unwind-resume.c
diff --git a/libpthread/nptl/sysdeps/pthread/pthread-unwind-forcedunwind.c b/libpthread/nptl/sysdeps/pthread/pthread-unwind-forcedunwind.c
new file mode 100644
index 0000000..fc04eb4
--- /dev/null
+++ b/libpthread/nptl/sysdeps/pthread/pthread-unwind-forcedunwind.c
@@ -0,0 +1 @@
+#include <unwind-forcedunwind.c>
-- 
2.7.4


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