Use multithread while compiling LLVM bitcode.
Since the LLVM multithread issue has been resolved,
we can use multithreaded compilation instead of
multi-process with pipe.
With this CL, we can reduce the strange deadlock
between "main" and "Compile Worker" process.
Change-Id: Ib2db7eb371347d6631a0dfc51a959a6237b5e513
diff --git a/src/compiler_llvm/compilation_unit.cc b/src/compiler_llvm/compilation_unit.cc
index 598a8b3..b8e8850 100644
--- a/src/compiler_llvm/compilation_unit.cc
+++ b/src/compiler_llvm/compilation_unit.cc
@@ -206,98 +206,17 @@
bool CompilationUnit::Materialize(size_t thread_count) {
MutexLock GUARD(cunit_lock_);
- if (thread_count == 1) {
- llvm::raw_string_ostream str_os(elf_image_);
- bool success = MaterializeToFile(str_os);
- LOG(INFO) << "Compilation Unit: " << elf_idx_ << (success ? " (done)" : " (failed)");
+ // Materialize the bitcode to elf_image_
+ llvm::raw_string_ostream str_os(elf_image_);
+ bool success = MaterializeToFile(str_os);
+ LOG(INFO) << "Compilation Unit: " << elf_idx_ << (success ? " (done)" : " (failed)");
- // Free the resources
- context_.reset(NULL);
- irb_.reset(NULL);
- module_ = NULL;
+ // Free the resources
+ context_.reset(NULL);
+ irb_.reset(NULL);
+ module_ = NULL;
- return success;
- }
-
- // Prepare the pipe between parent process and child process
- int pipe_fd[2];
- if (pipe(pipe_fd) == -1) {
- PLOG(FATAL) << "Failed to create pipe for CompilerWorker";
- return false;
- }
-
- // Fork a process to do the compilation
- pid_t pid = fork();
- if (pid < 0) {
- close(pipe_fd[0]);
- close(pipe_fd[1]);
- PLOG(FATAL) << "Failed to fork a process to do the compilation";
- return false;
-
- } else if (pid == 0) { // Child process
- // Close the unused pipe read end
- close(pipe_fd[0]);
-
- // Change process groups, so we don't get ripped by ProcessManager
- setpgid(0, 0);
-
- llvm::raw_fd_ostream fd_os(pipe_fd[1], /* shouldClose */true);
-
- // TODO: Should use exec* family instead of invoking a function.
- // Forward our compilation request to bcc.
- exit(static_cast<int>(!MaterializeToFile(fd_os)));
-
- } else { // Parent process
- // Close the unused pipe write end
- close(pipe_fd[1]);
-
- // Free the resources
- context_.reset(NULL);
- irb_.reset(NULL);
- module_ = NULL;
-
- // Read the result out from the pipe read end (until failure)
- const size_t buf_size = 1024;
- std::vector<uint8_t> buf(buf_size);
- while (true) {
- // Read from the pipe
- ssize_t nread = read(pipe_fd[0], &*buf.begin(), buf_size);
- if (nread < 0) {
- if (errno == EAGAIN || errno == EINTR) {
- continue;
- } else {
- LOG(ERROR) << "Unexpected error during IPC: " << strerror(errno);
- }
- }
-
- // Append to the end of the elf_image_
- elf_image_.append(buf.begin(), buf.begin() + nread);
-
- if (nread < static_cast<ssize_t>(buf_size)) { // EOF reached!
- break;
- }
- }
-
- close(pipe_fd[0]);
-
- // Wait for child to finish
- int status;
- pid_t got_pid = TEMP_FAILURE_RETRY(waitpid(pid, &status, 0));
- if (got_pid != pid) {
- PLOG(ERROR) << "waitpid failed: wanted " << pid << ", got " << got_pid;
- elf_image_.clear();
- return false;
- }
-
- if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
- LOG(ERROR) << "Failed to compile the bitcode: " << WEXITSTATUS(status);
- elf_image_.clear();
- return false;
- }
-
- LOG(INFO) << "Compilation Unit: " << elf_idx_ << " (done)";
- return true;
- }
+ return success;
}