Revert "Support RAII in wrapped_clang"

This reverts commit 202658759, which does
not correctly propagate Clang error codes.

PiperOrigin-RevId: 204991287

1 files changed, 50 insertions, 48 deletions

diff --git a/tools/osx/crosstool/wrapped_clang.cc b/tools/osx/crosstool/wrapped_clang.cc
index 232f082dc1..5f283a37fa 100644
--- a/tools/osx/crosstool/wrapped_clang.cc
+++ b/tools/osx/crosstool/wrapped_clang.cc
@@ -81,10 +81,19 @@ std::vector<const char *> ConvertToCArgs(const std::vector<std::string> &args) {
   return c_args;
 }
 
-// Spawns a subprocess for given arguments args. The first argument is used for
-// the executable path. Returns zero on success and an appropriate error number
-// otherwise.
-int RunSubProcess(const std::vector<std::string> &args) {
+// Turn our current process into a new process. Avoids fork overhead.
+// Never returns.
+void ExecProcess(const std::vector<std::string> &args) {
+  std::vector<const char *> exec_argv = ConvertToCArgs(args);
+  execv(args[0].c_str(), const_cast<char **>(exec_argv.data()));
+  std::cerr << "Error executing child process.'" <<  args[0] << "'. "
+            << strerror(errno) << "\n";
+  abort();
+}
+
+// Spawns a subprocess for given arguments args. The first argument is used
+// for the executable path.
+void RunSubProcess(const std::vector<std::string> &args) {
   std::vector<const char *> exec_argv = ConvertToCArgs(args);
   pid_t pid;
   int status = posix_spawn(&pid, args[0].c_str(), NULL, NULL,
@@ -97,19 +106,18 @@ int RunSubProcess(const std::vector<std::string> &args) {
     if (wait_status < 0) {
       std::cerr << "Error waiting on child process '" <<  args[0] << "'. "
                 << strerror(errno) << "\n";
-      return errno;
+      abort();
     }
     if (WEXITSTATUS(status) != 0) {
       std::cerr << "Error in child process '" <<  args[0] << "'. "
                 << WEXITSTATUS(status) << "\n";
-      return errno;
+      abort();
     }
   } else {
     std::cerr << "Error forking process '" <<  args[0] << "'. "
               << strerror(status) << "\n";
-    return status;
+    abort();
   }
-  return 0;
 }
 
 // Finds and replaces all instances of oldsub with newsub, in-place on str.
@@ -135,13 +143,13 @@ bool SetArgIfFlagPresent(const std::string &arg, const std::string &flagname,
   return false;
 }
 
-// Gets an environment variable in the current process environment. Logs an
-// error and returns the empty string if the variable is undefined.
+// Returns the DEVELOPER_DIR environment variable in the current process
+// environment. Aborts if this variable is unset.
 std::string GetMandatoryEnvVar(const std::string &var_name) {
   char *env_value = getenv(var_name.c_str());
-  if (env_value == nullptr || *env_value == '\0') {
+  if (env_value == nullptr) {
     std::cerr << "Error: " << var_name << " not set.\n";
-    return "";
+    abort();
   }
   return env_value;
 }
@@ -160,17 +168,11 @@ int main(int argc, char *argv[]) {
     std::cerr << "Binary must either be named 'wrapped_clang' or "
                  "'wrapped_clang_pp', not "
               << binary_name << "\n";
-    return EXIT_FAILURE;
+    abort();
   }
 
   std::string developer_dir = GetMandatoryEnvVar("DEVELOPER_DIR");
-  if (developer_dir.empty()) {
-    return EXIT_FAILURE;
-  }
   std::string sdk_root = GetMandatoryEnvVar("SDKROOT");
-  if (sdk_root.empty()) {
-    return EXIT_FAILURE;
-  }
 
   std::vector<std::string> processed_args = {"/usr/bin/xcrun", tool_name};
 
@@ -214,47 +216,47 @@ int main(int argc, char *argv[]) {
       std::cerr << "Error in clang wrapper: If any dsym "
               "hint is defined, then "
            << missing_dsym_flag << " must be defined\n";
-      return EXIT_FAILURE;
+      abort();
     } else {
       postprocess = true;
       dsyms_use_zip_file = !(dsym_bundle_zip.empty());
     }
   }
 
-  if (RunSubProcess(processed_args) != 0) {
-    return EXIT_FAILURE;
+  if (!postprocess) {
+    ExecProcess(processed_args);
+    std::cerr << "ExecProcess should not return. Please fix!\n";
+    abort();
   }
 
-  if (postprocess) {
-    std::vector<std::string> dsymutil_args = {"/usr/bin/xcrun", "dsymutil",
-                                              linked_binary, "-o", dsym_path};
-    if (!dsyms_use_zip_file) {
-      dsymutil_args.push_back("--flat");
-    }
+  RunSubProcess(processed_args);
 
-    if (RunSubProcess(dsymutil_args) != 0) {
-      return EXIT_FAILURE;
-    }
+  std::vector<std::string> dsymutil_args = {"/usr/bin/xcrun", "dsymutil",
+                                            linked_binary, "-o", dsym_path};
+  if (!dsyms_use_zip_file) {
+    dsymutil_args.push_back("--flat");
+  }
 
-    if (dsyms_use_zip_file) {
-      std::unique_ptr<char, decltype(std::free) *> cwd{getcwd(nullptr, 0),
-                                                       std::free};
-      if (cwd == nullptr) {
-        std::cerr << "Error determining current working directory\n";
-        return EXIT_FAILURE;
-      }
-      std::vector<std::string> zip_args = {
-          "/usr/bin/zip", "-q", "-r",
-          std::string(cwd.get()) + "/" + dsym_bundle_zip, "."};
-      if (chdir(dsym_path.c_str()) < 0) {
-        std::cerr << "Error changing directory to '" << dsym_path << "'\n";
-        return EXIT_FAILURE;
-      }
+  RunSubProcess(dsymutil_args);
 
-      if (RunSubProcess(zip_args) != 0) {
-        return EXIT_FAILURE;
-      }
+  if (dsyms_use_zip_file) {
+    std::unique_ptr<char, decltype(std::free) *> cwd{getcwd(nullptr, 0),
+                                                     std::free};
+    if (cwd == nullptr) {
+      std::cerr << "Error determining current working directory\n";
+      abort();
+    }
+    std::vector<std::string> zip_args = {
+        "/usr/bin/zip", "-q", "-r",
+        std::string(cwd.get()) + "/" + dsym_bundle_zip, "."};
+    if (chdir(dsym_path.c_str()) < 0) {
+      std::cerr << "Error changing directory to '" << dsym_path << "'\n";
+      abort();
     }
+
+    ExecProcess(zip_args);
+    std::cerr << "ExecProcess should not return. Please fix!\n";
+    abort();
   }
 
   return 0;