[gwp_asan] Exclude recoverable tests on Fuchsia

[Caslyn]

Summary

Exclude the set of tests that test recoverable code paths (i.e.
BacktraceGuardedPoolAllocator tests in recoverable.cpp) and always set
the Recoverable testing bool to false on the Fuchsia platform.
Signal handlers used by recoverable tests are unsupported on Fuchsia.

Death tests in backtrace.cpp use EXPECT_DEATH for compatibility
with zxtest.

[hctim]

LGTM w/ nit

compiler-rt/lib/gwp_asan/tests/harness.cpp

50–51

// Fuchsia does not support recoverable GWP-ASan.

[Caslyn]

Modify comment

compiler-rt/lib/gwp_asan/tests/backtrace.cpp

 TEST_P(BacktraceGuardedPoolAllocatorDeathTest, DoubleFree) {
   void *Ptr = AllocateMemory(GPA);
   DeallocateMemory(GPA, Ptr);
 
   std::string DeathRegex = "Double Free.*DeallocateMemory2.*";
   DeathRegex.append("was deallocated.*DeallocateMemory[^2].*");
   DeathRegex.append("was allocated.*AllocateMemory");
   if (!Recoverable) {
-    ASSERT_DEATH(DeallocateMemory2(GPA, Ptr), DeathRegex);
+    EXPECT_DEATH(DeallocateMemory2(GPA, Ptr), DeathRegex);
     return;
   }
 
   // For recoverable, assert that DeallocateMemory2() doesn't crash.
   DeallocateMemory2(GPA, Ptr);
   // Fuchsia's zxtest doesn't have an EXPECT_THAT(testing::MatchesRegex(), ...),
   // so check the regex manually.
   EXPECT_TRUE(std::regex_search(
#endif
   void *Ptr = AllocateMemory(GPA);
   DeallocateMemory(GPA, Ptr);
 
   std::string DeathRegex = "Use After Free.*TouchMemory.*";
   DeathRegex.append("was deallocated.*DeallocateMemory[^2].*");
   DeathRegex.append("was allocated.*AllocateMemory");
 
   if (!Recoverable) {
-    ASSERT_DEATH(TouchMemory(Ptr), DeathRegex);
+    EXPECT_DEATH(TouchMemory(Ptr), DeathRegex);
     return;
   }
 
   // For recoverable, assert that TouchMemory() doesn't crash.
   TouchMemory(Ptr);
   // Fuchsia's zxtest doesn't have an EXPECT_THAT(testing::MatchesRegex(), ...),
   // so check the regex manually.
   EXPECT_TRUE(std::regex_search(

compiler-rt/lib/gwp_asan/tests/harness.cpp

void CheckOnlyOneGwpAsanCrash(const std::string &OutputBuffer) {
   size_t FirstIndex = OutputBuffer.find(kGwpAsanErrorString);
   ASSERT_NE(FirstIndex, std::string::npos) << "Didn't detect a GWP-ASan crash";
   ASSERT_EQ(OutputBuffer.find(kGwpAsanErrorString, FirstIndex + 1),
             std::string::npos)
       << "Detected more than one GWP-ASan crash:\n"
       << OutputBuffer;
 }
 
+// Only test non-recoverable code paths on the Fuchsia platform because Fuchsia
+// does not support signal handlers used by recoverable tests.
+#if defined(__Fuchsia__)
+INSTANTIATE_TEST_SUITE_P(RecoverableAndNonRecoverableTests,
+                         BacktraceGuardedPoolAllocatorDeathTest,
+                         /* Recoverable */ testing::Values(false));
+#else
 INSTANTIATE_TEST_SUITE_P(RecoverableTests, BacktraceGuardedPoolAllocator,
                          /* Recoverable */ testing::Values(true));
 INSTANTIATE_TEST_SUITE_P(RecoverableAndNonRecoverableTests,
                          BacktraceGuardedPoolAllocatorDeathTest,
                          /* Recoverable */ testing::Bool());
+#endif