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

3 files changed, 37 insertions, 15 deletions

diff --git a/llvm/lib/Support/Signals.cpp b/llvm/lib/Support/Signals.cpp
index 3dc6b7c99d0..e5e38f59c04 100644
--- a/llvm/lib/Support/Signals.cpp
+++ b/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);
diff --git a/llvm/lib/Support/Unix/Signals.inc b/llvm/lib/Support/Unix/Signals.inc
index b49b8aae4ff..117d4e8bcb5 100644
--- a/llvm/lib/Support/Unix/Signals.inc
+++ b/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)
diff --git a/llvm/lib/Support/Windows/Signals.inc b/llvm/lib/Support/Windows/Signals.inc
index 3a0e5569f93..834f50ad10e 100644
--- a/llvm/lib/Support/Windows/Signals.inc
+++ b/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();