[sanitizer] Do not break the CFI unwind chain in clone().
Fixes build on clang 3.2, which doesn't support cfi_undefined. This change
doesn't seem to break the slow unwinder. Even if it does, the worst thing that
could happen is that we would not see a backtrace when a fatal error happens
under StopTheWorld.
git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@192196 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/sanitizer_common/sanitizer_linux.cc b/lib/sanitizer_common/sanitizer_linux.cc
index 10c112a..c1390ff 100644
--- a/lib/sanitizer_common/sanitizer_linux.cc
+++ b/lib/sanitizer_common/sanitizer_linux.cc
@@ -787,7 +787,6 @@
*/
"movq %6,%%r8\n"
"movq %7,%%r10\n"
- ".cfi_endproc\n"
"syscall\n"
/* if (%rax != 0)
@@ -797,8 +796,9 @@
"jnz 1f\n"
/* In the child. Terminate unwind chain. */
- ".cfi_startproc\n"
- ".cfi_undefined %%rip;\n"
+ // XXX: We should also terminate the CFI unwind chain
+ // here. Unfortunately clang 3.2 doesn't support the
+ // necessary CFI directives, so we skip that part.
"xorq %%rbp,%%rbp\n"
/* Call "fn(arg)". */