[CrashRecovery] Use SEH __try instead of VEH when available

Summary:
It avoids problems when other libraries raise exceptions. In particular,
OutputDebugString raises an exception that the debugger is supposed to
catch and suppress. VEH kicks in first right now, and that is entirely
incorrect.

Unfortunately, GCC does not support SEH, so I've kept the old buggy VEH
codepath around. We could fix it with SetUnhandledExceptionFilter, but
that is not per-thread, so a well-behaved library shouldn't set it.

Reviewers: zturner

Subscribers: llvm-commits, mgorny

Differential Revision: https://reviews.llvm.org/D33261

llvm-svn: 303274

1 files changed, 83 insertions, 0 deletions

diff --git a/llvm/unittests/Support/CrashRecoveryTest.cpp b/llvm/unittests/Support/CrashRecoveryTest.cpp
new file mode 100644
index 00000000000..dbb0db57679
--- /dev/null
+++ b/llvm/unittests/Support/CrashRecoveryTest.cpp
@@ -0,0 +1,83 @@
+//===- llvm/unittest/Support/CrashRecoveryTest.cpp ------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/CrashRecoveryContext.h"
+#include "llvm/Support/Compiler.h"
+#include "gtest/gtest.h"
+
+#ifdef LLVM_ON_WIN32
+#define WIN32_LEAN_AND_MEAN
+#define NOGDI
+#include <windows.h>
+#endif
+
+using namespace llvm;
+using namespace llvm::sys;
+
+static int GlobalInt = 0;
+static void nullDeref() { *(volatile int *)nullptr = 0; }
+static void incrementGlobal() { ++GlobalInt; }
+static void llvmTrap() { LLVM_BUILTIN_TRAP; }
+
+TEST(CrashRecoveryTest, Basic) {
+  llvm::CrashRecoveryContext::Enable();
+  GlobalInt = 0;
+  EXPECT_TRUE(CrashRecoveryContext().RunSafely(incrementGlobal));
+  EXPECT_EQ(1, GlobalInt);
+  EXPECT_FALSE(CrashRecoveryContext().RunSafely(nullDeref));
+  EXPECT_FALSE(CrashRecoveryContext().RunSafely(llvmTrap));
+}
+
+struct IncrementGlobalCleanup : CrashRecoveryContextCleanup {
+  IncrementGlobalCleanup(CrashRecoveryContext *CRC)
+      : CrashRecoveryContextCleanup(CRC) {}
+  virtual void recoverResources() { ++GlobalInt; }
+};
+
+static void noop() {}
+
+TEST(CrashRecoveryTest, Cleanup) {
+  llvm::CrashRecoveryContext::Enable();
+  GlobalInt = 0;
+  {
+    CrashRecoveryContext CRC;
+    CRC.registerCleanup(new IncrementGlobalCleanup(&CRC));
+    EXPECT_TRUE(CRC.RunSafely(noop));
+  } // run cleanups
+  EXPECT_EQ(1, GlobalInt);
+
+  GlobalInt = 0;
+  {
+    CrashRecoveryContext CRC;
+    CRC.registerCleanup(new IncrementGlobalCleanup(&CRC));
+    EXPECT_FALSE(CRC.RunSafely(nullDeref));
+  } // run cleanups
+  EXPECT_EQ(1, GlobalInt);
+}
+
+#ifdef LLVM_ON_WIN32
+static void raiseIt() {
+  RaiseException(123, EXCEPTION_NONCONTINUABLE, 0, NULL);
+}
+
+TEST(CrashRecoveryTest, RaiseException) {
+  llvm::CrashRecoveryContext::Enable();
+  EXPECT_FALSE(CrashRecoveryContext().RunSafely(raiseIt));
+}
+
+static void outputString() {
+  OutputDebugStringA("output for debugger\n");
+}
+
+TEST(CrashRecoveryTest, CallOutputDebugString) {
+  llvm::CrashRecoveryContext::Enable();
+  EXPECT_TRUE(CrashRecoveryContext().RunSafely(outputString));
+}
+
+#endif