Search for llvm-symbolizer binary in the same directory as argv[0], before

looking for it along $PATH. This allows installs of LLVM tools outside of
$PATH to find the symbolizer and produce pretty backtraces if they crash.

llvm-svn: 272232

Author: zygoloid

llvm/include/llvm/Support/Signals.h

@@ -38,8 +38,14 @@ namespace sys {
 
   /// When an error signal (such as SIBABRT or SIGSEGV) is delivered to the
   /// process, print a stack trace and then exit.
-  /// @brief Print a stack trace if a fatal signal occurs.
-  void PrintStackTraceOnErrorSignal(bool DisableCrashReporting = false);
+  /// \brief Print a stack trace if a fatal signal occurs.
+  /// \param Argv0 the current binary name, used to find the symbolizer
+  ///        relative to the current binary before searching $PATH; can be
+  ///        StringRef(), in which case we will only search $PATH.
+  /// \param DisableCrashReporting if \c true, disable the normal crash
+  ///        reporting mechanisms on the underlying operating system.
+  void PrintStackTraceOnErrorSignal(StringRef Argv0,
+                                    bool DisableCrashReporting = false);
 
   /// Disable all system dialog boxes that appear when the process crashes.
   void DisableSystemDialogsOnCrash();

llvm/lib/Support/Signals.cpp

@@ -62,28 +62,40 @@ static FormattedNumber format_ptr(void *PC) {
   return format_hex((uint64_t)PC, PtrWidth);
 }
 
-static bool printSymbolizedStackTrace(void **StackTrace, int Depth,
+static bool printSymbolizedStackTrace(StringRef Argv0,
+                                      void **StackTrace, int Depth,
                                       llvm::raw_ostream &OS)
   LLVM_ATTRIBUTE_USED;
 
 /// Helper that launches llvm-symbolizer and symbolizes a backtrace.
-static bool printSymbolizedStackTrace(void **StackTrace, int Depth,
+static bool printSymbolizedStackTrace(StringRef Argv0,
+                                      void **StackTrace, int Depth,
                                       llvm::raw_ostream &OS) {
+  // Don't recursively invoke the llvm-symbolizer binary.
+  if (Argv0.find("llvm-symbolizer") != std::string::npos)
+    return false;
+
   // FIXME: Subtract necessary number from StackTrace entries to turn return addresses
   // into actual instruction addresses.
-  // Use llvm-symbolizer tool to symbolize the stack traces.
-  ErrorOr<std::string> LLVMSymbolizerPathOrErr =
-      sys::findProgramByName("llvm-symbolizer");
+  // Use llvm-symbolizer tool to symbolize the stack traces. First look for it
+  // alongside our binary, then in $PATH.
+  ErrorOr<std::string> LLVMSymbolizerPathOrErr = std::error_code();
+  if (!Argv0.empty()) {
+    StringRef Parent = llvm::sys::path::parent_path(Argv0);
+    if (!Parent.empty())
+      LLVMSymbolizerPathOrErr = sys::findProgramByName("llvm-symbolizer", Parent);
+  }
+  if (!LLVMSymbolizerPathOrErr)
+    LLVMSymbolizerPathOrErr = sys::findProgramByName("llvm-symbolizer");
   if (!LLVMSymbolizerPathOrErr)
     return false;
   const std::string &LLVMSymbolizerPath = *LLVMSymbolizerPathOrErr;
-  // We don't know argv0 or the address of main() at this point, but try
-  // to guess it anyway (it's possible on some platforms).
-  std::string MainExecutableName = sys::fs::getMainExecutable(nullptr, nullptr);
-  if (MainExecutableName.empty() ||
-      MainExecutableName.find("llvm-symbolizer") != std::string::npos)
-    return false;
 
+  // If we don't know argv0 or the address of main() at this point, try
+  // to guess it anyway (it's possible on some platforms).
+  std::string MainExecutableName =
+      Argv0.empty() ? sys::fs::getMainExecutable(nullptr, nullptr)
+                    : (std::string)Argv0;
   BumpPtrAllocator Allocator;
   StringSaver StrPool(Allocator);
   std::vector<const char *> Modules(Depth, nullptr);

llvm/lib/Support/Unix/Signals.inc

@@ -68,6 +68,8 @@ static void (*InterruptFunction)() = nullptr;
 
 static ManagedStatic<std::vector<std::string>> FilesToRemove;
 
+static StringRef Argv0;
+
 // IntSigs - Signals that represent requested termination. There's no bug
 // or failure, or if there is, it's not our direct responsibility. For whatever
 // reason, our continued execution is no longer desirable.
@@ -408,7 +410,7 @@ void llvm::sys::PrintStackTrace(raw_ostream &OS) {
   if (!depth)
     return;
 
-  if (printSymbolizedStackTrace(StackTrace, depth, OS))
+  if (printSymbolizedStackTrace(Argv0, StackTrace, depth, OS))
     return;
 #if HAVE_DLFCN_H && __GNUG__
   int width = 0;
@@ -471,7 +473,10 @@ void llvm::sys::DisableSystemDialogsOnCrash() {}
 
 /// PrintStackTraceOnErrorSignal - When an error signal (such as SIGABRT or
 /// SIGSEGV) is delivered to the process, print a stack trace and then exit.
-void llvm::sys::PrintStackTraceOnErrorSignal(bool DisableCrashReporting) {
+void llvm::sys::PrintStackTraceOnErrorSignal(StringRef Argv0,
+                                             bool DisableCrashReporting) {
+  ::Argv0 = Argv0;
+
   AddSignalHandler(PrintStackTraceSignalHandler, nullptr);
 
 #if defined(__APPLE__) && defined(ENABLE_CRASH_OVERRIDES)

llvm/lib/Support/Windows/Signals.inc

@@ -206,6 +206,8 @@ static PTOP_LEVEL_EXCEPTION_FILTER OldFilter = NULL;
 static CRITICAL_SECTION CriticalSection;
 static bool CriticalSectionInitialized = false;
 
+static StringRef Argv0;
+
 enum {
 #if defined(_M_X64)
   NativeMachineType = IMAGE_FILE_MACHINE_AMD64
@@ -240,7 +242,7 @@ static bool printStackTraceWithLLVMSymbolizer(llvm::raw_ostream &OS,
       break;
   }
 
-  return printSymbolizedStackTrace(&StackTrace[0], Depth, OS);
+  return printSymbolizedStackTrace(Argv0, &StackTrace[0], Depth, OS);
 }
 
 namespace {
@@ -496,7 +498,10 @@ void sys::DisableSystemDialogsOnCrash() {
 
 /// PrintStackTraceOnErrorSignal - When an error signal (such as SIBABRT or
 /// SIGSEGV) is delivered to the process, print a stack trace and then exit.
-void sys::PrintStackTraceOnErrorSignal(bool DisableCrashReporting) {
+void sys::PrintStackTraceOnErrorSignal(StringRef Argv0,
+                                       bool DisableCrashReporting) {
+  ::Argv0 = Argv0;
+
   if (DisableCrashReporting || getenv("LLVM_DISABLE_CRASH_REPORT"))
     Process::PreventCoreFiles();
 

llvm/tools/bugpoint/bugpoint.cpp

@@ -113,7 +113,7 @@ void initializePollyPasses(llvm::PassRegistry &Registry);
 
 int main(int argc, char **argv) {
 #ifndef DEBUG_BUGPOINT
-  llvm::sys::PrintStackTraceOnErrorSignal();
+  llvm::sys::PrintStackTraceOnErrorSignal(argv[0]);
   llvm::PrettyStackTraceProgram X(argc, argv);
   llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
 #endif

llvm/tools/dsymutil/dsymutil.cpp

@@ -237,7 +237,7 @@ void llvm::dsymutil::exitDsymutil(int ExitStatus) {
 }
 
 int main(int argc, char **argv) {
-  llvm::sys::PrintStackTraceOnErrorSignal();
+  llvm::sys::PrintStackTraceOnErrorSignal(argv[0]);
   llvm::PrettyStackTraceProgram StackPrinter(argc, argv);
   llvm::llvm_shutdown_obj Shutdown;
   LinkOptions Options;

llvm/tools/llc/llc.cpp

@@ -202,7 +202,7 @@ static void DiagnosticHandler(const DiagnosticInfo &DI, void *Context) {
 // main - Entry point for the llc compiler.
 //
 int main(int argc, char **argv) {
-  sys::PrintStackTraceOnErrorSignal();
+  sys::PrintStackTraceOnErrorSignal(argv[0]);
   PrettyStackTraceProgram X(argc, argv);
 
   // Enable debug stream buffering.

llvm/tools/lli/lli.cpp

@@ -365,7 +365,7 @@ CodeGenOpt::Level getOptLevel() {
 // main Driver function
 //
 int main(int argc, char **argv, char * const *envp) {
-  sys::PrintStackTraceOnErrorSignal();
+  sys::PrintStackTraceOnErrorSignal(argv[0]);
   PrettyStackTraceProgram X(argc, argv);
 
   atexit(llvm_shutdown); // Call llvm_shutdown() on exit.

llvm/tools/llvm-ar/llvm-ar.cpp

@@ -773,7 +773,7 @@ static int ranlib_main() {
 int main(int argc, char **argv) {
   ToolName = argv[0];
   // Print a stack trace if we signal out.
-  sys::PrintStackTraceOnErrorSignal();
+  sys::PrintStackTraceOnErrorSignal(argv[0]);
   PrettyStackTraceProgram X(argc, argv);
   llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
 

llvm/tools/llvm-as/llvm-as.cpp

@@ -89,7 +89,7 @@ static void WriteOutputFile(const Module *M) {
 
 int main(int argc, char **argv) {
   // Print a stack trace if we signal out.
-  sys::PrintStackTraceOnErrorSignal();
+  sys::PrintStackTraceOnErrorSignal(argv[0]);
   PrettyStackTraceProgram X(argc, argv);
   LLVMContext Context;
   llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.