[asan] Add fallback for Thumb after r350139

[rovka]

Summary

This reverts r350806 which marked some tests as UNSUPPORTED on ARM and
instead reintroduces the old code path only for Thumb, since that seems
to be the only target that broke.

It would still be nice to find the root cause of the breakage, but with
the branch point for LLVM 8.0 scheduled for next week it's better to put
things in a stable state while we investigate.

[krytarowski]

lib/asan/asan_rtl.cc

386 ↗

(On Diff #181245)

I would prefer to additionally specify Linux here, but for now it's good enough.

[krytarowski]

lib/asan/asan_rtl.cc

386 ↗

(On Diff #181245)

Or maybe even better (feel free to pick a better symbol name):

#if defined(__thumb__) && defined(__linux__)
#define START_BACKGROUND_THREAD_IN_ASAN_INTERNAL
#endif

#ifndef START_BACKGROUND_THREAD_IN_ASAN_INTERNAL
static bool UNUSED __local_asan_dyninit = [] {
  MaybeStartBackgroudThread();
  SetSoftRssLimitExceededCallback(AsanSoftRssLimitExceededCallback);

  return false;
}();
#endif

static void AsanInitInternal() {
[...]
MaybeStartBackgroudThread();
SetSoftRssLimitExceededCallback(AsanSoftRssLimitExceededCallback);
[...]
}

BTW. Does it work on thumb if we use here:

 __attribute__((constructor))
void __local_asan_dyninit() {
  MaybeStartBackgroudThread();
  SetSoftRssLimitExceededCallback(AsanSoftRssLimitExceededCallback);
}

[rovka]

Thanks for the review, I'll commit with your suggestions in place.

lib/asan/asan_rtl.cc

386 ↗

(On Diff #181245)

The constructor attribute doesn't work (in fact it breaks even on arm, and in more tests than before).

[krytarowski]

lib/asan/asan_rtl.cc

386 ↗

(On Diff #181245)

This means that something is really wrong. Feel free to land this patch or the proposed one with START_BACKGROUND_THREAD_IN_ASAN_INTERNAL.

compiler-rt/trunk/lib/asan/asan_rtl.cc

void PrintAddressSpaceLayout() {
   Printf("SHADOW_OFFSET: 0x%zx\n", (uptr)SHADOW_OFFSET);
   CHECK(SHADOW_SCALE >= 3 && SHADOW_SCALE <= 7);
   if (kMidMemBeg)
     CHECK(kMidShadowBeg > kLowShadowEnd &&
           kMidMemBeg > kMidShadowEnd &&
           kHighShadowBeg > kMidMemEnd);
 }
 
+#if defined(__thumb__) && defined(__linux__)
+#define START_BACKGROUND_THREAD_IN_ASAN_INTERNAL
+#endif
+
+#ifndef START_BACKGROUND_THREAD_IN_ASAN_INTERNAL
 static bool UNUSED __local_asan_dyninit = [] {
   MaybeStartBackgroudThread();
   SetSoftRssLimitExceededCallback(AsanSoftRssLimitExceededCallback);
 
   return false;
 }();
+#endif
 
 static void AsanInitInternal() {
   if (LIKELY(asan_inited)) return;
   SanitizerToolName = "AddressSanitizer";
   CHECK(!asan_init_is_running && "ASan init calls itself!");
   asan_init_is_running = true;
 
   CacheBinaryName();
static void AsanInitInternal() {
 
   AsanTSDInit(PlatformTSDDtor);
   InstallDeadlySignalHandlers(AsanOnDeadlySignal);
 
   AllocatorOptions allocator_options;
   allocator_options.SetFrom(flags(), common_flags());
   InitializeAllocator(allocator_options);
 
+#ifdef START_BACKGROUND_THREAD_IN_ASAN_INTERNAL
+  MaybeStartBackgroudThread();
+  SetSoftRssLimitExceededCallback(AsanSoftRssLimitExceededCallback);
+#endif
+
   // On Linux AsanThread::ThreadStart() calls malloc() that's why asan_inited
   // should be set to 1 prior to initializing the threads.
   asan_inited = 1;
   asan_init_is_running = false;
 
   if (flags()->atexit)
     Atexit(asan_atexit);
 

compiler-rt/trunk/test/asan/TestCases/Linux/quarantine_size_mb.cc

 // Test quarantine_size_mb (and the deprecated quarantine_size)
 // RUN: %clangxx_asan  %s -o %t
 // RUN: %env_asan_opts=quarantine_size=10485760:verbosity=1:hard_rss_limit_mb=50 %run %t  2>&1 | FileCheck %s  --check-prefix=Q10
 // RUN: %env_asan_opts=quarantine_size_mb=10:verbosity=1:hard_rss_limit_mb=50    %run %t  2>&1 | FileCheck %s  --check-prefix=Q10
 // RUN: %env_asan_opts=quarantine_size_mb=10:quarantine_size=20:verbosity=1  not %run %t  2>&1 | FileCheck %s  --check-prefix=BOTH
 // RUN: %env_asan_opts=quarantine_size_mb=1000:hard_rss_limit_mb=50 not  %run %t          2>&1 | FileCheck %s  --check-prefix=RSS_LIMIT
 // RUN: %env_asan_opts=hard_rss_limit_mb=20                         not  %run %t          2>&1 | FileCheck %s  --check-prefix=RSS_LIMIT
 
 // https://github.com/google/sanitizers/issues/981
-// UNSUPPORTED: android-26, arm
+// UNSUPPORTED: android-26
 
 #include <string.h>
 char *g;
 
 static const int kNumAllocs = 1 << 11;
 static const int kAllocSize = 1 << 20;
 
 int main() {

compiler-rt/trunk/test/sanitizer_common/TestCases/hard_rss_limit_mb_test.cc

 // RUN: %run %t
 //
 // FIXME: make it work for other sanitizers.
 // XFAIL: lsan
 // XFAIL: tsan
 // XFAIL: msan
 // XFAIL: ubsan
 
-// UNSUPPORTED: freebsd, solaris, darwin, arm
+// UNSUPPORTED: freebsd, solaris, darwin
 
 #include <string.h>
 #include <stdio.h>
 #include <unistd.h>
 
 const int kNumAllocs = 200 * 1000;
 const int kAllocSize = 1000;
 volatile char *sink[kNumAllocs];