[MSan] Print current stack on CHECK violation

Summary:
Print current stack on CHECK violation to aid debugging and
match other sanitizers functionality.

Reviewers: eugenis

Subscribers: delcypher, llvm-commits, #sanitizers

Differential Revision: https://reviews.llvm.org/D43692

llvm-svn: 326105

compiler-rt/lib/msan/msan.cc

@@ -379,6 +379,14 @@ static void MsanOnDeadlySignal(int signo, void *siginfo, void *context) {
   HandleDeadlySignal(siginfo, context, GetTid(), &OnStackUnwind, nullptr);
 }
 
+static void MsanCheckFailed(const char *file, int line, const char *cond,
+                            u64 v1, u64 v2) {
+  Report("MemorySanitizer CHECK failed: %s:%d \"%s\" (0x%zx, 0x%zx)\n", file,
+         line, cond, (uptr)v1, (uptr)v2);
+  PRINT_CURRENT_STACK_CHECK();
+  Die();
+}
+
 void __msan_init() {
   CHECK(!msan_init_is_running);
   if (msan_inited) return;
@@ -391,6 +399,9 @@ void __msan_init() {
   CacheBinaryName();
   InitializeFlags();
 
+  // Install tool-specific callbacks in sanitizer_common.
+  SetCheckFailedCallback(MsanCheckFailed);
+
   __sanitizer_set_report_path(common_flags()->log_path);
 
   InitializeInterceptors();

compiler-rt/lib/msan/msan.h

@@ -356,14 +356,23 @@ const int STACK_TRACE_TAG_POISON = StackTrace::TAG_CUSTOM + 1;
                     common_flags()->fast_unwind_on_malloc);               \
   }
 
+#define GET_STORE_STACK_TRACE \
+  GET_STORE_STACK_TRACE_PC_BP(StackTrace::GetCurrentPc(), GET_CURRENT_FRAME())
+
 #define GET_FATAL_STACK_TRACE_PC_BP(pc, bp)              \
   BufferedStackTrace stack;                              \
   if (msan_inited)                                       \
   GetStackTrace(&stack, kStackTraceMax, pc, bp, nullptr, \
                 common_flags()->fast_unwind_on_fatal)
 
-#define GET_STORE_STACK_TRACE \
-  GET_STORE_STACK_TRACE_PC_BP(StackTrace::GetCurrentPc(), GET_CURRENT_FRAME())
+#define GET_FATAL_STACK_TRACE_HERE \
+  GET_FATAL_STACK_TRACE_PC_BP(StackTrace::GetCurrentPc(), GET_CURRENT_FRAME())
+
+#define PRINT_CURRENT_STACK_CHECK() \
+  {                                 \
+    GET_FATAL_STACK_TRACE_HERE;     \
+    stack.Print();                  \
+  }
 
 class ScopedThreadLocalStateBackup {
  public:

compiler-rt/test/msan/check-handler.cc

@@ -0,0 +1,16 @@
+// RUN: %clangxx_msan -O0 -g %s -o %t && not %run %t 2>&1 | FileCheck %s
+
+// Verify that CHECK handler prints a stack on CHECK fail.
+
+#include <stdlib.h>
+
+int main(void) {
+  // Allocate chunk from the secondary allocator to trigger CHECK(IsALigned())
+  // in its free() path.
+  void *p = malloc(8 << 20);
+  free(reinterpret_cast<char*>(p) + 1);
+  // CHECK: MemorySanitizer: bad pointer
+  // CHECK: MemorySanitizer CHECK failed
+  // CHECK: #0
+  return 0;
+}