[compiler-rt] r343153 - [sanitizer] AndroidGetApiLevel for static executables.

[Evgeniy Stepanov via llvm-commits]

Author: eugenis
Date: Wed Sep 26 16:48:13 2018
New Revision: 343153

URL: http://llvm.org/viewvc/llvm-project?rev=343153&view=rev
Log:
[sanitizer] AndroidGetApiLevel for static executables.

A version of AndroidGetApiLevel for static executables that is
completely compile-time.

The generic version uses dl_iterate_phdr which, even though it works
in static executables, crashes if called before libc is initialized.

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

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=343153&r1=343152&r2=343153&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.cc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.cc Wed Sep 26 16:48:13 2018
@@ -1671,6 +1671,16 @@ static int dl_iterate_phdr_test_cb(struc
 
 static atomic_uint32_t android_api_level;
 
+static AndroidApiLevel AndroidDetectApiLevelStatic() {
+#if __ANDROID_API__ <= 19
+  return ANDROID_KITKAT;
+#elif __ANDROID_API__ <= 22
+  return ANDROID_LOLLIPOP_MR1;
+#else
+  return ANDROID_POST_LOLLIPOP;
+#endif
+}
+
 static AndroidApiLevel AndroidDetectApiLevel() {
   if (!&dl_iterate_phdr)
     return ANDROID_KITKAT; // K or lower
@@ -1683,11 +1693,14 @@ static AndroidApiLevel AndroidDetectApiL
   // interesting to detect.
 }
 
+extern "C" __attribute__((weak)) void* _DYNAMIC;
+
 AndroidApiLevel AndroidGetApiLevel() {
   AndroidApiLevel level =
       (AndroidApiLevel)atomic_load(&android_api_level, memory_order_relaxed);
   if (level) return level;
-  level = AndroidDetectApiLevel();
+  level = &_DYNAMIC == nullptr ? AndroidDetectApiLevelStatic()
+                               : AndroidDetectApiLevel();
   atomic_store(&android_api_level, level, memory_order_relaxed);
   return level;
 }