Use a temporary file for output which gets renamed after all the writing is finished.
This mainly prevents failures and/or crashes when multiple processes try to read/write the same PCH file. (rdar://8392711&8294781); suggestion & review by Daniel!
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@114187 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Frontend/CompilerInstance.cpp b/lib/Frontend/CompilerInstance.cpp
index ce0b072..212a1cf 100644
--- a/lib/Frontend/CompilerInstance.cpp
+++ b/lib/Frontend/CompilerInstance.cpp
@@ -35,6 +35,7 @@
#include "llvm/System/Host.h"
#include "llvm/System/Path.h"
#include "llvm/System/Program.h"
+#include "llvm/System/Signals.h"
using namespace clang;
CompilerInstance::CompilerInstance()
@@ -370,18 +371,30 @@
// Output Files
-void CompilerInstance::addOutputFile(llvm::StringRef Path,
- llvm::raw_ostream *OS) {
- assert(OS && "Attempt to add empty stream to output list!");
- OutputFiles.push_back(std::make_pair(Path, OS));
+void CompilerInstance::addOutputFile(const OutputFile &OutFile) {
+ assert(OutFile.OS && "Attempt to add empty stream to output list!");
+ OutputFiles.push_back(OutFile);
}
void CompilerInstance::clearOutputFiles(bool EraseFiles) {
- for (std::list< std::pair<std::string, llvm::raw_ostream*> >::iterator
+ for (std::list<OutputFile>::iterator
it = OutputFiles.begin(), ie = OutputFiles.end(); it != ie; ++it) {
- delete it->second;
- if (EraseFiles && !it->first.empty())
- llvm::sys::Path(it->first).eraseFromDisk();
+ delete it->OS;
+ if (!it->TempFilename.empty()) {
+ llvm::sys::Path TempPath(it->TempFilename);
+ if (EraseFiles)
+ TempPath.eraseFromDisk();
+ else {
+ std::string Error;
+ if (TempPath.renamePathOnDisk(llvm::sys::Path(it->Filename), &Error)) {
+ getDiagnostics().Report(diag::err_fe_unable_to_rename_temp)
+ << it->TempFilename << it->Filename << Error;
+ TempPath.eraseFromDisk();
+ }
+ }
+ } else if (!it->Filename.empty() && EraseFiles)
+ llvm::sys::Path(it->Filename).eraseFromDisk();
+
}
OutputFiles.clear();
}
@@ -399,10 +412,11 @@
bool Binary,
llvm::StringRef InFile,
llvm::StringRef Extension) {
- std::string Error, OutputPathName;
+ std::string Error, OutputPathName, TempPathName;
llvm::raw_fd_ostream *OS = createOutputFile(OutputPath, Error, Binary,
InFile, Extension,
- &OutputPathName);
+ &OutputPathName,
+ &TempPathName);
if (!OS) {
getDiagnostics().Report(diag::err_fe_unable_to_open_output)
<< OutputPath << Error;
@@ -411,7 +425,8 @@
// Add the output file -- but don't try to remove "-", since this means we are
// using stdin.
- addOutputFile((OutputPathName != "-") ? OutputPathName : "", OS);
+ addOutputFile(OutputFile((OutputPathName != "-") ? OutputPathName : "",
+ TempPathName, OS));
return OS;
}
@@ -422,8 +437,9 @@
bool Binary,
llvm::StringRef InFile,
llvm::StringRef Extension,
- std::string *ResultPathName) {
- std::string OutFile;
+ std::string *ResultPathName,
+ std::string *TempPathName) {
+ std::string OutFile, TempFile;
if (!OutputPath.empty()) {
OutFile = OutputPath;
} else if (InFile == "-") {
@@ -436,15 +452,37 @@
} else {
OutFile = "-";
}
+
+ if (OutFile != "-") {
+ llvm::sys::Path OutPath(OutFile);
+ // Only create the temporary if we can actually write to OutPath, otherwise
+ // we want to fail early.
+ if (!OutPath.exists() ||
+ (OutPath.isRegularFile() && OutPath.canWrite())) {
+ // Create a temporary file.
+ llvm::sys::Path TempPath(OutFile);
+ if (!TempPath.createTemporaryFileOnDisk())
+ TempFile = TempPath.str();
+ }
+ }
+
+ std::string OSFile = OutFile;
+ if (!TempFile.empty())
+ OSFile = TempFile;
llvm::OwningPtr<llvm::raw_fd_ostream> OS(
- new llvm::raw_fd_ostream(OutFile.c_str(), Error,
+ new llvm::raw_fd_ostream(OSFile.c_str(), Error,
(Binary ? llvm::raw_fd_ostream::F_Binary : 0)));
if (!Error.empty())
return 0;
+ // Make sure the out stream file gets removed if we crash.
+ llvm::sys::RemoveFileOnSignal(llvm::sys::Path(OSFile));
+
if (ResultPathName)
*ResultPathName = OutFile;
+ if (TempPathName)
+ *TempPathName = TempFile;
return OS.take();
}