Overhaul the symbolizer interface.

This moves away from creating the symbolizer object and initializing the
external symbolizer as separate steps.  Those steps now always take place
together.

Sanitizers with a legacy requirement to specify their own symbolizer path
should use InitSymbolizer to initialize the symbolizer with the desired
path, and GetSymbolizer to access the symbolizer.  Sanitizers with no
such requirement (e.g. UBSan) can use GetOrInitSymbolizer with no need for
initialization.

The symbolizer interface has been made thread-safe (as far as I can
tell) by protecting its member functions with mutexes.

Finally, the symbolizer interface no longer relies on weak externals, the
introduction of which was probably a mistake on my part.

Differential Revision: http://llvm-reviews.chandlerc.com/D1985

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@193448 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 47 insertions, 0 deletions

diff --git a/lib/sanitizer_common/sanitizer_symbolizer_libcdep.cc b/lib/sanitizer_common/sanitizer_symbolizer_libcdep.cc
new file mode 100644
index 00000000..ada7be15
--- /dev/null
+++ b/lib/sanitizer_common/sanitizer_symbolizer_libcdep.cc
@@ -0,0 +1,47 @@
+//===-- sanitizer_symbolizer_libcdep.cc -----------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is shared between AddressSanitizer and ThreadSanitizer
+// run-time libraries.
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_platform.h"
+#include "sanitizer_internal_defs.h"
+#include "sanitizer_placement_new.h"
+#include "sanitizer_symbolizer.h"
+
+namespace __sanitizer {
+
+Symbolizer *Symbolizer::CreateAndStore(const char *path_to_external) {
+  Symbolizer *platform_symbolizer = PlatformInit(path_to_external);
+  if (!platform_symbolizer) return Disable();
+  atomic_store(&symbolizer_, reinterpret_cast<uptr>(platform_symbolizer),
+               memory_order_release);
+  return platform_symbolizer;
+}
+
+Symbolizer *Symbolizer::Init(const char *path_to_external) {
+  CHECK_EQ(0, atomic_load(&symbolizer_, memory_order_acquire));
+  return CreateAndStore(path_to_external);
+}
+
+Symbolizer *Symbolizer::GetOrInit() {
+  static StaticSpinMutex init_mu;
+
+  uptr sym = atomic_load(&symbolizer_, memory_order_acquire);
+  if (!sym) {
+    SpinMutexLock l(&init_mu);
+    sym = atomic_load(&symbolizer_, memory_order_relaxed);
+    if (!sym) return CreateAndStore(0);
+  }
+
+  return reinterpret_cast<Symbolizer *>(sym);
+}
+
+}  // namespace __sanitizer