src: print backtrace on failed CHECK/ASSERT

Print a C backtrace on fatal errors to make it easier to debug issues.

PR-URL: https://github.com/nodejs/node/pull/6734
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

src/node.cc

@@ -1795,6 +1795,31 @@ NO_RETURN void Abort() {
 }
 
 
+NO_RETURN void Assert(const char* const (*args)[4]) {
+  auto filename = (*args)[0];
+  auto linenum = (*args)[1];
+  auto message = (*args)[2];
+  auto function = (*args)[3];
+
+  char exepath[256];
+  size_t exepath_size = sizeof(exepath);
+  if (uv_exepath(exepath, &exepath_size))
+    snprintf(exepath, sizeof(exepath), "node");
+
+  char pid[12] = {0};
+#ifndef _WIN32
+  snprintf(pid, sizeof(pid), "[%u]", getpid());
+#endif
+
+  fprintf(stderr, "%s%s: %s:%s:%s%s Assertion `%s' failed.\n",
+          exepath, pid, filename, linenum,
+          function, *function ? ":" : "", message);
+  fflush(stderr);
+
+  Abort();
+}
+
+
 static void Abort(const FunctionCallbackInfo<Value>& args) {
   Abort();
 }

src/util.h

@@ -25,7 +25,10 @@ namespace node {
 #define NO_RETURN
 #endif
 
+// The slightly odd function signature for Assert() is to ease
+// instruction cache pressure in calls from ASSERT and CHECK.
 NO_RETURN void Abort();
+NO_RETURN void Assert(const char* const (*args)[4]);
 void DumpBacktrace(FILE* fp);
 
 #ifdef __APPLE__
@@ -52,15 +55,40 @@ template <typename T> using remove_reference = std::remove_reference<T>;
 
 #define ABORT() node::Abort()
 
-#if defined(NDEBUG)
+#ifdef __GNUC__
-# define ASSERT(expression)
+#define LIKELY(expr) __builtin_expect(!!(expr), 1)
-# define CHECK(expression)                                                    \
+#define UNLIKELY(expr) __builtin_expect(!!(expr), 0)
+#define PRETTY_FUNCTION_NAME __PRETTY_FUNCTION__
+#else
+#define LIKELY(expr) expr
+#define UNLIKELY(expr) expr
+#define PRETTY_FUNCTION_NAME ""
+#endif
+
+#define STRINGIFY_(x) #x
+#define STRINGIFY(x) STRINGIFY_(x)
+
+#define CHECK(expr)                                                           \
   do {                                                                        \
-    if (!(expression)) ABORT();                                               \
+    if (UNLIKELY(!(expr))) {                                                  \
+      static const char* const args[] = { __FILE__, STRINGIFY(__LINE__),      \
+                                          #expr, PRETTY_FUNCTION_NAME };      \
+      node::Assert(&args);                                                    \
+    }                                                                         \
   } while (0)
+
+// FIXME(bnoordhuis) cctests don't link in node::Abort() and node::Assert().
+#ifdef GTEST_DONT_DEFINE_ASSERT_EQ
+#undef ABORT
+#undef CHECK
+#define ABORT ABORT_NO_BACKTRACE
+#define CHECK assert
+#endif
+
+#ifdef NDEBUG
+#define ASSERT(expr)
 #else
-# define ASSERT(expression)  assert(expression)
+#define ASSERT(expr) CHECK(expr)
-# define CHECK(expression)   assert(expression)
 #endif
 
 #define ASSERT_EQ(a, b) ASSERT((a) == (b))