[standalone] Fix finding symbols when argv[0] is not an absolute path or relative to CWD.

TEST=vm/dart/symbolized_crash_test
Change-Id: I941045db6ab78b24bd529e775380be80c1d71121
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/339782
Reviewed-by: Alexander Aprelev <[email protected]>
Commit-Queue: Ryan Macnak <[email protected]>

Author: rmacnak-google

runtime/bin/exe_utils.cc

@@ -122,21 +122,22 @@ Utils::CStringUniquePtr EXEUtils::GetDirectoryPrefixFromExeName() {
 }
 
 #if !defined(DART_HOST_OS_WINDOWS)
-void EXEUtils::LoadDartProfilerSymbols(const char* exepath) {
-  int len = strlen(exepath);
-  char* sympath = reinterpret_cast<char*>(malloc(len + 5));
-  memcpy(sympath, exepath, len);     // NOLINT
-  memcpy(sympath + len, ".sym", 5);  // NOLINT
-  File* file = File::Open(nullptr, sympath, File::kRead);
-  free(sympath);
-  if (file != nullptr) {
-    int64_t size = file->Length();
-    MappedMemory* mapping = file->Map(File::kReadOnly, 0, size);
-    Dart_AddSymbols(exepath, mapping->address(), size);
-    mapping->Leak();  // Let us delete the object but keep the mapping.
-    delete mapping;
-    file->Release();
-  }
+void EXEUtils::LoadDartProfilerSymbols(const char* argv0) {
+  char* path = reinterpret_cast<char*>(malloc(PATH_MAX + 5));
+  if (Platform::ResolveExecutablePathInto(path, PATH_MAX) <= 0) return;
+
+  int len = strlen(path);
+  memcpy(path + len, ".sym", 5);  // NOLINT
+  File* file = File::Open(nullptr, path, File::kRead);
+  free(path);
+  if (file == nullptr) return;
+
+  int64_t size = file->Length();
+  MappedMemory* mapping = file->Map(File::kReadOnly, 0, size);
+  Dart_AddSymbols(argv0, mapping->address(), size);
+  mapping->Leak();  // Let us delete the object but keep the mapping.
+  delete mapping;
+  file->Release();
 }
 #endif  // !defined(DART_HOST_OS_WINDOWS)
 

runtime/tests/vm/dart/symbolized_crash_test.dart

@@ -11,9 +11,13 @@ main() {
   if (Platform.isWindows) return; // posix exit codes
   if (Platform.isAndroid) return; // run_vm_tests not available on test device
 
-  var run_vm_tests =
-      path.join(path.dirname(Platform.resolvedExecutable), "run_vm_tests");
-  var result = Process.runSync(run_vm_tests, ["Fatal"]);
+  // Run such that "cwd/argv[0].sym" does not exist to check .sym properly
+  // resolves against the executable.
+  var dir = path.dirname(Platform.resolvedExecutable);
+  var result = Process.runSync(
+    "/bin/sh",
+    ["-c", "PATH=$dir run_vm_tests Fatal"],
+  );
   print(result.exitCode);
   print(result.stdout);
   print(result.stderr);