add __sync_synchronize. Needed by compiler when emitting thumb1 with -fno-builtin

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@95132 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 33 insertions, 0 deletions

diff --git a/lib/arm/sync_synchronize.S b/lib/arm/sync_synchronize.S
new file mode 100644
index 000000000..40b584e10
--- /dev/null
+++ b/lib/arm/sync_synchronize.S
@@ -0,0 +1,33 @@
+//===-- sync_synchronize - Implement memory barrier * ----------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "../assembly.h"
+
+//
+// When compiling a use of the gcc built-in __sync_synchronize() in thumb1 mode
+// the compiler may emit a call to __sync_synchronize.  
+// On Darwin the implementation jumps to an OS supplied function named 
+// OSMemoryBarrier
+//
+
+	.text
+	.syntax unified
+
+#if __APPLE__
+
+DEFINE_COMPILERRT_PRIVATE_FUNCTION(__sync_synchronize)
+	stmfd	sp!, {r7, lr}
+	add		r7, sp, #0
+	bl		_OSMemoryBarrier
+	ldmfd	sp!, {r7, pc}
+
+	// tell linker it can break up file at label boundaries
+	.subsections_via_symbols
+		
+#endif