libsanitizer/

	* All source files: Merge from upstream 285547.
	* configure.tgt (SANITIZER_COMMON_TARGET_DEPENDENT_OBJECTS): New
	variable.
	* configure.ac (SANITIZER_COMMON_TARGET_DEPENDENT_OBJECTS): Handle it.
	* asan/Makefile.am (asan_files): Add new files.
	* asan/Makefile.in: Regenerate.
	* ubsan/Makefile.in: Likewise.
	* lsan/Makefile.in: Likewise.
	* tsan/Makefile.am (tsan_files): Add new files.
	* tsan/Makefile.in: Regenerate.
	* sanitizer_common/Makefile.am (sanitizer_common_files): Add new files.
	(EXTRA_libsanitizer_common_la_SOURCES): Define.
	(libsanitizer_common_la_LIBADD): Likewise.
	(libsanitizer_common_la_DEPENDENCIES): Likewise.
	* sanitizer_common/Makefile.in: Regenerate.
	* interception/Makefile.in: Likewise.
	* libbacktace/Makefile.in: Likewise.
	* Makefile.in: Likewise.
	* configure: Likewise.
	* merge.sh: Handle builtins/assembly.h merging.
	* builtins/assembly.h: New file.
	* asan/libtool-version: Bump the libasan SONAME.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@241977 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 10 insertions, 0 deletions

diff --git a/libsanitizer/sanitizer_common/sanitizer_unwind_linux_libcdep.cc b/libsanitizer/sanitizer_common/sanitizer_unwind_linux_libcdep.cc
index 408c21c913bb..eb1c133e4f4e 100644
--- a/libsanitizer/sanitizer_common/sanitizer_unwind_linux_libcdep.cc
+++ b/libsanitizer/sanitizer_common/sanitizer_unwind_linux_libcdep.cc
@@ -46,6 +46,11 @@ unwind_backtrace_signal_arch_func unwind_backtrace_signal_arch;
 
 #if SANITIZER_ANDROID
 void SanitizerInitializeUnwinder() {
+  if (AndroidGetApiLevel() >= ANDROID_LOLLIPOP_MR1) return;
+
+  // Pre-lollipop Android can not unwind through signal handler frames with
+  // libgcc unwinder, but it has a libcorkscrew.so library with the necessary
+  // workarounds.
   void *p = dlopen("libcorkscrew.so", RTLD_LAZY);
   if (!p) {
     VReport(1,
@@ -101,6 +106,11 @@ _Unwind_Reason_Code Unwind_Trace(struct _Unwind_Context *ctx, void *param) {
   UnwindTraceArg *arg = (UnwindTraceArg*)param;
   CHECK_LT(arg->stack->size, arg->max_depth);
   uptr pc = Unwind_GetIP(ctx);
+  const uptr kPageSize = GetPageSizeCached();
+  // Let's assume that any pointer in the 0th page (i.e. <0x1000 on i386 and
+  // x86_64) is invalid and stop unwinding here.  If we're adding support for
+  // a platform where this isn't true, we need to reconsider this check.
+  if (pc < kPageSize) return UNWIND_STOP;
   arg->stack->trace_buffer[arg->stack->size++] = pc;
   if (arg->stack->size == arg->max_depth) return UNWIND_STOP;
   return UNWIND_CONTINUE;