[compiler-rt] r312687 - [asan] Add a note to shadow memory setup error.

[Evgeniy Stepanov via llvm-commits]

Author: eugenis
Date: Wed Sep  6 18:35:59 2017
New Revision: 312687

URL: http://llvm.org/viewvc/llvm-project?rev=312687&view=rev
Log:
[asan] Add a note to shadow memory setup error.

Point to https://github.com/google/sanitizers/issues/856 as a possible cause of the failed mapping.

Modified:
    compiler-rt/trunk/lib/asan/asan_shadow_setup.cc

Modified: compiler-rt/trunk/lib/asan/asan_shadow_setup.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/asan_shadow_setup.cc?rev=312687&r1=312686&r2=312687&view=diff
==============================================================================
--- compiler-rt/trunk/lib/asan/asan_shadow_setup.cc (original)
+++ compiler-rt/trunk/lib/asan/asan_shadow_setup.cc Wed Sep  6 18:35:59 2017
@@ -81,6 +81,15 @@ static void ProtectGap(uptr addr, uptr s
   Die();
 }
 
+static void MaybeReportLinuxPIEBug() {
+#if SANITIZER_LINUX && (defined(__x86_64__) || defined(__aarch64__))
+  Report("This might be related to ELF_ET_DYN_BASE change in Linux 4.12.\n");
+  Report(
+      "See https://github.com/google/sanitizers/issues/837 for possible "
+      "workarounds.\n");
+#endif
+}
+
 void InitializeShadowMemory() {
   // Set the shadow memory address to uninitialized.
   __asan_shadow_memory_dynamic_address = kDefaultShadowSentinel;
@@ -141,6 +150,7 @@ void InitializeShadowMemory() {
         "ASan cannot proceed correctly. ABORTING.\n");
     Report("ASan shadow was supposed to be located in the [%p-%p] range.\n",
            shadow_start, kHighShadowEnd);
+    MaybeReportLinuxPIEBug();
     DumpProcessMap();
     Die();
   }