Dump stack trace on segfault in the VM.

Install a signal handler in the standalone VM that dumps a backtrace
similar to what we already do on assertion failures.

For now only Linux and MacOS are supported.

BUG=
R=asiva@google.com

Review URL: https://codereview.chromium.org/2514113002 .

runtime/bin/platform_linux.cc

@@ -22,6 +22,12 @@ char* Platform::resolved_executable_name_ = NULL;
 int Platform::script_index_ = 1;
 char** Platform::argv_ = NULL;
 
+
+static void segv_handler(int signal, siginfo_t* siginfo, void* context) {
+  Dart_DumpNativeStackTrace(context);
+  abort();
+}
+
 bool Platform::Initialize() {
   // Turn off the signal handler for SIGPIPE as it causes the process
   // to terminate on writing to a closed pipe. Without the signal
@@ -33,6 +39,21 @@ bool Platform::Initialize() {
     perror("Setting signal handler failed");
     return false;
   }
+
+  act.sa_flags = SA_SIGINFO;
+  act.sa_sigaction = &segv_handler;
+  if (sigemptyset(&act.sa_mask) != 0) {
+    perror("sigemptyset() failed.");
+    return false;
+  }
+  if (sigaddset(&act.sa_mask, SIGPROF) != 0) {
+    perror("sigaddset() failed");
+    return false;
+  }
+  if (sigaction(SIGSEGV, &act, NULL) != 0) {
+    perror("sigaction() failed.");
+    return false;
+  }
   return true;
 }
 

runtime/bin/platform_macos.cc

@@ -39,6 +39,20 @@ bool Platform::Initialize() {
     perror("Setting signal handler failed");
     return false;
   }
+  act.sa_flags = SA_SIGINFO;
+  act.sa_sigaction = &segv_handler;
+  if (sigemptyset(&act.sa_mask) != 0) {
+    perror("sigemptyset() failed.");
+    return false;
+  }
+  if (sigaddset(&act.sa_mask, SIGPROF) != 0) {
+    perror("sigaddset() failed");
+    return false;
+  }
+  if (sigaction(SIGSEGV, &act, NULL) != 0) {
+    perror("sigaction() failed.");
+    return false;
+  }
   return true;
 }
 

runtime/include/dart_api.h

@@ -3281,4 +3281,10 @@ Dart_CreateAppJITSnapshot(uint8_t** vm_isolate_snapshot_buffer,
  */
 DART_EXPORT bool Dart_IsPrecompiledRuntime();
 
+
+/**
+ *  Print a native stack trace. Used for crash handling.
+ */
+DART_EXPORT void Dart_DumpNativeStackTrace(void* context);
+
 #endif /* INCLUDE_DART_API_H_ */ /* NOLINT */

runtime/vm/dart_api_impl.cc

@@ -6671,4 +6671,9 @@ DART_EXPORT bool Dart_IsPrecompiledRuntime() {
 #endif
 }
 
+
+DART_EXPORT void Dart_DumpNativeStackTrace(void* context) {
+  Profiler::DumpStackTrace(context);
+}
+
 }  // namespace dart

runtime/vm/profiler.cc

@@ -944,7 +944,36 @@ static uintptr_t __attribute__((noinline)) GetProgramCounter() {
 #endif
 
 
+void Profiler::DumpStackTrace(void* context) {
+#if defined(TARGET_OS_LINUX) || defined(TARGET_OS_MACOS)
+  ucontext_t* ucontext = reinterpret_cast<ucontext_t*>(context);
+  mcontext_t mcontext = ucontext->uc_mcontext;
+  uword pc = SignalHandler::GetProgramCounter(mcontext);
+  uword fp = SignalHandler::GetFramePointer(mcontext);
+  uword sp = SignalHandler::GetCStackPointer(mcontext);
+  DumpStackTrace(/* native_stack_trace = */ true, sp, fp, pc);
+#else
+// TODO(fschneider): Add support for more platforms.
+// Do nothing on unsupported platforms.
+#endif
+}
+
+
 void Profiler::DumpStackTrace(bool native_stack_trace) {
+  uintptr_t sp = Thread::GetCurrentStackPointer();
+  uintptr_t fp = 0;
+  uintptr_t pc = GetProgramCounter();
+
+  COPY_FP_REGISTER(fp);
+
+  DumpStackTrace(native_stack_trace, sp, fp, pc);
+}
+
+
+void Profiler::DumpStackTrace(bool native_stack_trace,
+                              uword sp,
+                              uword fp,
+                              uword pc) {
   // Allow only one stack trace to prevent recursively printing stack traces if
   // we hit an assert while printing the stack.
   static uintptr_t started_dump = 0;
@@ -970,12 +999,6 @@ void Profiler::DumpStackTrace(bool native_stack_trace) {
                native_stack_trace ? "native" : "dart-only",
                OSThread::ThreadIdToIntPtr(os_thread->trace_id()));
 
-  uintptr_t sp = Thread::GetCurrentStackPointer();
-  uintptr_t fp = 0;
-  uintptr_t pc = GetProgramCounter();
-
-  COPY_FP_REGISTER(fp);
-
   uword stack_lower = 0;
   uword stack_upper = 0;
 

runtime/vm/profiler.h

@@ -54,6 +54,7 @@ class Profiler : public AllStatic {
 
   static SampleBuffer* sample_buffer() { return sample_buffer_; }
 
+  static void DumpStackTrace(void* context);
   static void DumpStackTrace(bool native_stack_trace = true);
 
   static void SampleAllocation(Thread* thread, intptr_t cid);
@@ -74,6 +75,11 @@ class Profiler : public AllStatic {
   }
 
  private:
+  static void DumpStackTrace(bool native_stack_trace,
+                             uword sp,
+                             uword fp,
+                             uword pc);
+
   // Does not walk the thread's stack.
   static void SampleThreadSingleFrame(Thread* thread, uintptr_t pc);
   static bool initialized_;