Fix tmp files being left on Windows builds.

Clang writes object files by first writing to a .tmp file and then
renaming to the final .obj name. On Windows, if a compile is killed
partway through the .tmp files don't get deleted.

Currently it seems like RemoveFileOnSignal takes care of deleting the
tmp files on Linux, but on Windows we need to call
setDeleteDisposition on tmp files so that they are deleted when
closed.

This patch switches to using TempFile to create the .tmp files we write
when creating object files, since it uses setDeleteDisposition on Windows.
This change applies to both Linux and Windows for consistency.

Differential Revision: https://reviews.llvm.org/D102876

clang/include/clang/Frontend/CompilerInstance.h

@@ -22,6 +22,7 @@
 #include "llvm/ADT/IntrusiveRefCntPtr.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/BuryPointer.h"
+#include "llvm/Support/FileSystem.h"
 #include <cassert>
 #include <list>
 #include <memory>
@@ -165,11 +166,10 @@ class CompilerInstance : public ModuleLoader {
   /// failed.
   struct OutputFile {
     std::string Filename;
-    std::string TempFilename;
+    Optional<llvm::sys::fs::TempFile> File;
 
-    OutputFile(std::string filename, std::string tempFilename)
-        : Filename(std::move(filename)), TempFilename(std::move(tempFilename)) {
-    }
+    OutputFile(std::string filename, Optional<llvm::sys::fs::TempFile> file)
+        : Filename(std::move(filename)), File(std::move(file)) {}
   };
 
   /// The list of active output files.

clang/lib/Frontend/CompilerInstance.cpp

@@ -703,31 +703,37 @@ void CompilerInstance::createSema(TranslationUnitKind TUKind,
 // Output Files
 
 void CompilerInstance::clearOutputFiles(bool EraseFiles) {
+  // Ignore errors that occur when trying to discard the temp file.
   for (OutputFile &OF : OutputFiles) {
     if (EraseFiles) {
-      if (!OF.TempFilename.empty()) {
-        llvm::sys::fs::remove(OF.TempFilename);
-        continue;
-      }
+      if (OF.File)
+        consumeError(OF.File->discard());
       if (!OF.Filename.empty())
         llvm::sys::fs::remove(OF.Filename);
       continue;
     }
 
-    if (OF.TempFilename.empty())
+    if (!OF.File)
       continue;
 
+    if (OF.File->TmpName.empty()) {
+      consumeError(OF.File->discard());
+      continue;
+    }
+
     // If '-working-directory' was passed, the output filename should be
     // relative to that.
     SmallString<128> NewOutFile(OF.Filename);
     FileMgr->FixupRelativePath(NewOutFile);
-    std::error_code EC = llvm::sys::fs::rename(OF.TempFilename, NewOutFile);
-    if (!EC)
-      continue;
-    getDiagnostics().Report(diag::err_unable_to_rename_temp)
-        << OF.TempFilename << OF.Filename << EC.message();
 
-    llvm::sys::fs::remove(OF.TempFilename);
+    llvm::Error E = OF.File->keep(NewOutFile);
+    if (!E)
+      continue;
+
+    getDiagnostics().Report(diag::err_unable_to_rename_temp)
+        << OF.File->TmpName << OF.Filename << std::move(E);
+
+    llvm::sys::fs::remove(OF.File->TmpName);
   }
   OutputFiles.clear();
   if (DeleteBuiltModules) {
@@ -809,7 +815,7 @@ CompilerInstance::createOutputFileImpl(StringRef OutputPath, bool Binary,
     }
   }
 
-  std::string TempFile;
+  Optional<llvm::sys::fs::TempFile> Temp;
   if (UseTemporary) {
     // Create a temporary file.
     // Insert -%%%%%%%% before the extension (if any), and because some tools
@@ -821,25 +827,36 @@ CompilerInstance::createOutputFileImpl(StringRef OutputPath, bool Binary,
     TempPath += "-%%%%%%%%";
     TempPath += OutputExtension;
     TempPath += ".tmp";
-    int fd;
-    std::error_code EC = llvm::sys::fs::createUniqueFile(
-        TempPath, fd, TempPath,
-        Binary ? llvm::sys::fs::OF_None : llvm::sys::fs::OF_Text);
+    Expected<llvm::sys::fs::TempFile> ExpectedFile =
+        llvm::sys::fs::TempFile::create(TempPath);
 
-    if (CreateMissingDirectories &&
-        EC == llvm::errc::no_such_file_or_directory) {
-      StringRef Parent = llvm::sys::path::parent_path(OutputPath);
-      EC = llvm::sys::fs::create_directories(Parent);
-      if (!EC) {
-        EC = llvm::sys::fs::createUniqueFile(TempPath, fd, TempPath,
-                                             Binary ? llvm::sys::fs::OF_None
-                                                    : llvm::sys::fs::OF_Text);
-      }
-    }
+    llvm::Error E = handleErrors(
+        ExpectedFile.takeError(), [&](const llvm::ECError &E) -> llvm::Error {
+          std::error_code EC = E.convertToErrorCode();
+          if (CreateMissingDirectories &&
+              EC == llvm::errc::no_such_file_or_directory) {
+            StringRef Parent = llvm::sys::path::parent_path(OutputPath);
+            EC = llvm::sys::fs::create_directories(Parent);
+            if (!EC) {
+              ExpectedFile = llvm::sys::fs::TempFile::create(TempPath);
+              if (!ExpectedFile)
+                return llvm::errorCodeToError(
+                    llvm::errc::no_such_file_or_directory);
+            }
+          }
+          return llvm::errorCodeToError(EC);
+        });
 
-    if (!EC) {
-      OS.reset(new llvm::raw_fd_ostream(fd, /*shouldClose=*/true));
-      OSFile = TempFile = std::string(TempPath.str());
+    if (E) {
+      consumeError(std::move(E));
+    } else {
+      Temp = std::move(ExpectedFile.get());
+      TempPath = Temp->TmpName;
+
+      OS.reset(new llvm::raw_fd_ostream(Temp->FD, /*shouldClose=*/false,
+                                        Binary ? llvm::sys::fs::OF_None
+                                               : llvm::sys::fs::OF_Text));
+      OSFile = std::string(TempPath.str());
     }
     // If we failed to create the temporary, fallback to writing to the file
     // directly. This handles the corner case where we cannot write to the
@@ -863,7 +880,7 @@ CompilerInstance::createOutputFileImpl(StringRef OutputPath, bool Binary,
   // Add the output file -- but don't try to remove "-", since this means we are
   // using stdin.
   OutputFiles.emplace_back(((OutputPath != "-") ? OutputPath : "").str(),
-                           std::move(TempFile));
+                           std::move(Temp));
 
   if (!Binary || OS->supportsSeeking())
     return std::move(OS);

llvm/lib/Support/Path.cpp

@@ -1229,7 +1229,7 @@ Error TempFile::keep(const Twine &Name) {
   auto H = reinterpret_cast<HANDLE>(_get_osfhandle(FD));
   std::error_code RenameEC = setDeleteDisposition(H, false);
   if (!RenameEC) {
-    RenameEC = rename_fd(FD, Name);
+    RenameEC = rename_handle(H, Name);
     // If rename failed because it's cross-device, copy instead
     if (RenameEC ==
       std::error_code(ERROR_NOT_SAME_DEVICE, std::system_category())) {

llvm/lib/Support/Windows/Path.inc

@@ -560,11 +560,6 @@ static std::error_code rename_handle(HANDLE FromHandle, const Twine &To) {
   return errc::permission_denied;
 }
 
-static std::error_code rename_fd(int FromFD, const Twine &To) {
-  HANDLE FromHandle = reinterpret_cast<HANDLE>(_get_osfhandle(FromFD));
-  return rename_handle(FromHandle, To);
-}
-
 std::error_code rename(const Twine &From, const Twine &To) {
   // Convert to utf-16.
   SmallVector<wchar_t, 128> WideFrom;