Use raw_pwrite_stream in clang.

This is a small improvement to -emit-pth and allows llvm to start requiring it.

llvm-svn: 234897

5 files changed, 52 insertions, 43 deletions

diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index 7c443cc8059..4353b30d3c4 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -96,7 +96,7 @@ private:
 
   void CreatePasses();
 
-  /// CreateTargetMachine - Generates the TargetMachine.
+  /// Generates the TargetMachine.
   /// Returns Null if it is unable to create the target machine.
   /// Some of our clang tests specify triples which are not built
   /// into clang. This is okay because these tests check the generated
@@ -106,10 +106,10 @@ private:
   /// the requested target.
   TargetMachine *CreateTargetMachine(bool MustCreateTM);
 
-  /// AddEmitPasses - Add passes necessary to emit assembly or LLVM IR.
+  /// Add passes necessary to emit assembly or LLVM IR.
   ///
   /// \return True on success.
-  bool AddEmitPasses(BackendAction Action, raw_ostream &OS);
+  bool AddEmitPasses(BackendAction Action, raw_pwrite_stream &OS);
 
 public:
   EmitAssemblyHelper(DiagnosticsEngine &_Diags,
@@ -132,7 +132,7 @@ public:
 
   std::unique_ptr<TargetMachine> TM;
 
-  void EmitAssembly(BackendAction Action, raw_ostream *OS);
+  void EmitAssembly(BackendAction Action, raw_pwrite_stream *OS);
 };
 
 // We need this wrapper to access LangOpts and CGOpts from extension functions
@@ -545,7 +545,8 @@ TargetMachine *EmitAssemblyHelper::CreateTargetMachine(bool MustCreateTM) {
   return TM;
 }
 
-bool EmitAssemblyHelper::AddEmitPasses(BackendAction Action, raw_ostream &OS) {
+bool EmitAssemblyHelper::AddEmitPasses(BackendAction Action,
+                                       raw_pwrite_stream &OS) {
 
   // Create the code generator passes.
   legacy::PassManager *PM = getCodeGenPasses();
@@ -582,7 +583,8 @@ bool EmitAssemblyHelper::AddEmitPasses(BackendAction Action, raw_ostream &OS) {
   return true;
 }
 
-void EmitAssemblyHelper::EmitAssembly(BackendAction Action, raw_ostream *OS) {
+void EmitAssemblyHelper::EmitAssembly(BackendAction Action,
+                                      raw_pwrite_stream *OS) {
   TimeRegion Region(llvm::TimePassesIsEnabled ? &CodeGenerationTime : nullptr);
 
   bool UsesCodeGen = (Action != Backend_EmitNothing &&
@@ -644,7 +646,7 @@ void clang::EmitBackendOutput(DiagnosticsEngine &Diags,
                               const clang::TargetOptions &TOpts,
                               const LangOptions &LOpts, StringRef TDesc,
                               Module *M, BackendAction Action,
-                              raw_ostream *OS) {
+                              raw_pwrite_stream *OS) {
   EmitAssemblyHelper AsmHelper(Diags, CGOpts, TOpts, LOpts, M);
 
   AsmHelper.EmitAssembly(Action, OS);
diff --git a/clang/lib/CodeGen/CodeGenAction.cpp b/clang/lib/CodeGen/CodeGenAction.cpp
index b5ed12aee31..60aac0782e2 100644
--- a/clang/lib/CodeGen/CodeGenAction.cpp
+++ b/clang/lib/CodeGen/CodeGenAction.cpp
@@ -46,7 +46,7 @@ namespace clang {
     const CodeGenOptions &CodeGenOpts;
     const TargetOptions &TargetOpts;
     const LangOptions &LangOpts;
-    raw_ostream *AsmOutStream;
+    raw_pwrite_stream *AsmOutStream;
     ASTContext *Context;
 
     Timer LLVMIRGeneration;
@@ -61,7 +61,7 @@ namespace clang {
                     const TargetOptions &targetopts,
                     const LangOptions &langopts, bool TimePasses,
                     const std::string &infile, llvm::Module *LinkModule,
-                    raw_ostream *OS, LLVMContext &C,
+                    raw_pwrite_stream *OS, LLVMContext &C,
                     CoverageSourceInfo *CoverageInfo = nullptr)
         : Diags(_Diags), Action(action), CodeGenOpts(compopts),
           TargetOpts(targetopts), LangOpts(langopts), AsmOutStream(OS),
@@ -601,9 +601,8 @@ llvm::LLVMContext *CodeGenAction::takeLLVMContext() {
   return VMContext;
 }
 
-static raw_ostream *GetOutputStream(CompilerInstance &CI,
-                                    StringRef InFile,
-                                    BackendAction Action) {
+static raw_pwrite_stream *
+GetOutputStream(CompilerInstance &CI, StringRef InFile, BackendAction Action) {
   switch (Action) {
   case Backend_EmitAssembly:
     return CI.createDefaultOutputFile(false, InFile, "s");
@@ -625,7 +624,7 @@ static raw_ostream *GetOutputStream(CompilerInstance &CI,
 std::unique_ptr<ASTConsumer>
 CodeGenAction::CreateASTConsumer(CompilerInstance &CI, StringRef InFile) {
   BackendAction BA = static_cast<BackendAction>(Act);
-  std::unique_ptr<raw_ostream> OS(GetOutputStream(CI, InFile, BA));
+  std::unique_ptr<raw_pwrite_stream> OS(GetOutputStream(CI, InFile, BA));
   if (BA != Backend_EmitNothing && !OS)
     return nullptr;
 
@@ -678,7 +677,7 @@ void CodeGenAction::ExecuteAction() {
   if (getCurrentFileKind() == IK_LLVM_IR) {
     BackendAction BA = static_cast<BackendAction>(Act);
     CompilerInstance &CI = getCompilerInstance();
-    raw_ostream *OS = GetOutputStream(CI, getCurrentFile(), BA);
+    raw_pwrite_stream *OS = GetOutputStream(CI, getCurrentFile(), BA);
     if (BA != Backend_EmitNothing && !OS)
       return;
 
diff --git a/clang/lib/Frontend/CacheTokens.cpp b/clang/lib/Frontend/CacheTokens.cpp
index 68429d9686a..7d2a09cd7ca 100644
--- a/clang/lib/Frontend/CacheTokens.cpp
+++ b/clang/lib/Frontend/CacheTokens.cpp
@@ -183,7 +183,7 @@ class PTHWriter {
   typedef llvm::StringMap<OffsetOpt, llvm::BumpPtrAllocator> CachedStrsTy;
 
   IDMap IM;
-  llvm::raw_fd_ostream& Out;
+  raw_pwrite_stream &Out;
   Preprocessor& PP;
   uint32_t idcount;
   PTHMap PM;
@@ -236,8 +236,8 @@ class PTHWriter {
   Offset EmitCachedSpellings();
 
 public:
-  PTHWriter(llvm::raw_fd_ostream& out, Preprocessor& pp)
-    : Out(out), PP(pp), idcount(0), CurStrOffset(0) {}
+  PTHWriter(raw_pwrite_stream &out, Preprocessor &pp)
+      : Out(out), PP(pp), idcount(0), CurStrOffset(0) {}
 
   PTHMap &getPM() { return PM; }
   void GeneratePTH(const std::string &MainFile);
@@ -468,6 +468,16 @@ Offset PTHWriter::EmitCachedSpellings() {
   return SpellingsOff;
 }
 
+static uint32_t swap32le(uint32_t X) {
+  return llvm::support::endian::byte_swap<uint32_t, llvm::support::little>(X);
+}
+
+static void pwrite32le(raw_pwrite_stream &OS, uint32_t Val, uint64_t &Off) {
+  uint32_t LEVal = swap32le(Val);
+  OS.pwrite(reinterpret_cast<const char *>(&LEVal), 4, Off);
+  Off += 4;
+}
+
 void PTHWriter::GeneratePTH(const std::string &MainFile) {
   // Generate the prologue.
   Out << "cfe-pth" << '\0';
@@ -520,11 +530,11 @@ void PTHWriter::GeneratePTH(const std::string &MainFile) {
   Offset FileTableOff = EmitFileTable();
 
   // Finally, write the prologue.
-  Out.seek(PrologueOffset);
-  Emit32(IdTableOff.first);
-  Emit32(IdTableOff.second);
-  Emit32(FileTableOff);
-  Emit32(SpellingOff);
+  uint64_t Off = PrologueOffset;
+  pwrite32le(Out, IdTableOff.first, Off);
+  pwrite32le(Out, IdTableOff.second, Off);
+  pwrite32le(Out, FileTableOff, Off);
+  pwrite32le(Out, SpellingOff, Off);
 }
 
 namespace {
@@ -559,8 +569,7 @@ public:
 };
 } // end anonymous namespace
 
-
-void clang::CacheTokens(Preprocessor &PP, llvm::raw_fd_ostream* OS) {
+void clang::CacheTokens(Preprocessor &PP, raw_pwrite_stream *OS) {
   // Get the name of the main file.
   const SourceManager &SrcMgr = PP.getSourceManager();
   const FileEntry *MainFile = SrcMgr.getFileEntryForID(SrcMgr.getMainFileID());
diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index 0628442f9b1..fdaf7e2a5f8 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -550,11 +550,11 @@ void CompilerInstance::clearOutputFiles(bool EraseFiles) {
 
   }
   OutputFiles.clear();
+  NonSeekStream.reset();
 }
 
-llvm::raw_fd_ostream *
-CompilerInstance::createDefaultOutputFile(bool Binary,
-                                          StringRef InFile,
+raw_pwrite_stream *
+CompilerInstance::createDefaultOutputFile(bool Binary, StringRef InFile,
                                           StringRef Extension) {
   return createOutputFile(getFrontendOpts().OutputFile, Binary,
                           /*RemoveFileOnSignal=*/true, InFile, Extension,
@@ -568,16 +568,14 @@ llvm::raw_null_ostream *CompilerInstance::createNullOutputFile() {
   return Ret;
 }
 
-llvm::raw_fd_ostream *
-CompilerInstance::createOutputFile(StringRef OutputPath,
-                                   bool Binary, bool RemoveFileOnSignal,
-                                   StringRef InFile,
-                                   StringRef Extension,
-                                   bool UseTemporary,
+raw_pwrite_stream *
+CompilerInstance::createOutputFile(StringRef OutputPath, bool Binary,
+                                   bool RemoveFileOnSignal, StringRef InFile,
+                                   StringRef Extension, bool UseTemporary,
                                    bool CreateMissingDirectories) {
   std::string OutputPathName, TempPathName;
   std::error_code EC;
-  std::unique_ptr<llvm::raw_fd_ostream> OS = createOutputFile(
+  std::unique_ptr<raw_pwrite_stream> OS = createOutputFile(
       OutputPath, EC, Binary, RemoveFileOnSignal, InFile, Extension,
       UseTemporary, CreateMissingDirectories, &OutputPathName, &TempPathName);
   if (!OS) {
@@ -586,7 +584,7 @@ CompilerInstance::createOutputFile(StringRef OutputPath,
     return nullptr;
   }
 
-  llvm::raw_fd_ostream *Ret = OS.get();
+  raw_pwrite_stream *Ret = OS.get();
   // Add the output file -- but don't try to remove "-", since this means we are
   // using stdin.
   addOutputFile(OutputFile((OutputPathName != "-") ? OutputPathName : "",
@@ -595,7 +593,7 @@ CompilerInstance::createOutputFile(StringRef OutputPath,
   return Ret;
 }
 
-std::unique_ptr<llvm::raw_fd_ostream> CompilerInstance::createOutputFile(
+std::unique_ptr<llvm::raw_pwrite_stream> CompilerInstance::createOutputFile(
     StringRef OutputPath, std::error_code &Error, bool Binary,
     bool RemoveFileOnSignal, StringRef InFile, StringRef Extension,
     bool UseTemporary, bool CreateMissingDirectories,
@@ -683,7 +681,13 @@ std::unique_ptr<llvm::raw_fd_ostream> CompilerInstance::createOutputFile(
   if (TempPathName)
     *TempPathName = TempFile;
 
-  return OS;
+  if (!Binary || OS->supportsSeeking())
+    return std::move(OS);
+
+  auto B = llvm::make_unique<llvm::buffer_ostream>(*OS);
+  assert(!NonSeekStream);
+  NonSeekStream = std::move(OS);
+  return std::move(B);
 }
 
 // Initialization Utilities
diff --git a/clang/lib/Frontend/FrontendActions.cpp b/clang/lib/Frontend/FrontendActions.cpp
index 5ffe65f9f2a..0defe5c0c32 100644
--- a/clang/lib/Frontend/FrontendActions.cpp
+++ b/clang/lib/Frontend/FrontendActions.cpp
@@ -599,15 +599,10 @@ void DumpTokensAction::ExecuteAction() {
 
 void GeneratePTHAction::ExecuteAction() {
   CompilerInstance &CI = getCompilerInstance();
-  llvm::raw_fd_ostream *OS = CI.createDefaultOutputFile(true, getCurrentFile());
+  raw_pwrite_stream *OS = CI.createDefaultOutputFile(true, getCurrentFile());
   if (!OS)
     return;
 
-  if (!OS->supportsSeeking()) {
-    // FIXME: Don't fail this way.
-    llvm::report_fatal_error("PTH requires a seekable file for output!");
-  }
-
   CacheTokens(CI.getPreprocessor(), OS);
 }