[compiler-rt] r217764 - [asan] Delay system log initialization on Android.

[Evgeniy Stepanov]

Author: eugenis
Date: Mon Sep 15 06:37:40 2014
New Revision: 217764

URL: http://llvm.org/viewvc/llvm-project?rev=217764&view=rev
Log:
[asan] Delay system log initialization on Android.

Writing to system log requires libc interceptors to be initialized.
Fixes crashes with verbosity=1 on newer Android builds.

Modified:
    compiler-rt/trunk/lib/asan/asan_rtl.cc
    compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h
    compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.cc

Modified: compiler-rt/trunk/lib/asan/asan_rtl.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/asan_rtl.cc?rev=217764&r1=217763&r2=217764&view=diff
==============================================================================
--- compiler-rt/trunk/lib/asan/asan_rtl.cc (original)
+++ compiler-rt/trunk/lib/asan/asan_rtl.cc Mon Sep 15 06:37:40 2014
@@ -592,6 +592,11 @@ static void AsanInitInternal() {
 
   InitializeAsanInterceptors();
 
+  // Enable system log ("adb logcat") on Android.
+  // Doing this before interceptors are initialized crashes in:
+  // AsanInitInternal -> android_log_write -> __interceptor_strcmp
+  AndroidLogInit();
+
   ReplaceSystemMalloc();
 
   uptr shadow_start = kLowShadowBeg;

Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h?rev=217764&r1=217763&r2=217764&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h Mon Sep 15 06:37:40 2014
@@ -544,10 +544,13 @@ F IndirectExternCall(F f) {
 #endif
 
 #if SANITIZER_ANDROID
+// Initialize Android logging. Any writes before this are silently lost.
+void AndroidLogInit();
 void AndroidLogWrite(const char *buffer);
 void GetExtraActivationFlags(char *buf, uptr size);
 void SanitizerInitializeUnwinder();
 #else
+INLINE void AndroidLogInit() {}
 INLINE void AndroidLogWrite(const char *buffer_unused) {}
 INLINE void GetExtraActivationFlags(char *buf, uptr size) { *buf = '\0'; }
 INLINE void SanitizerInitializeUnwinder() {}

Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.cc?rev=217764&r1=217763&r2=217764&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.cc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.cc Mon Sep 15 06:37:40 2014
@@ -836,11 +836,19 @@ uptr internal_clone(int (*fn)(void *), v
 #endif  // defined(__x86_64__) && SANITIZER_LINUX
 
 #if SANITIZER_ANDROID
+static atomic_uint8_t android_log_initialized;
+
+void AndroidLogInit() {
+  atomic_store(&android_log_initialized, 1, memory_order_release);
+}
 // This thing is not, strictly speaking, async signal safe, but it does not seem
 // to cause any issues. Alternative is writing to log devices directly, but
 // their location and message format might change in the future, so we'd really
 // like to avoid that.
 void AndroidLogWrite(const char *buffer) {
+  if (!atomic_load(&android_log_initialized, memory_order_acquire))
+    return;
+
   char *copy = internal_strdup(buffer);
   char *p = copy;
   char *q;