Frontend: Switch -header-include-file output to use unbuffered raw_ostreams with

the atomic writes option, since the intent is that this option be set for an
entire build, which may have any number of compiler instances writing to the
same output file.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@124772 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Basic/DiagnosticFrontendKinds.td

@@ -77,6 +77,8 @@ def err_fe_pth_file_has_no_source_header : Error<
     "PTH file '%0' does not designate an original source header file for -include-pth">;
 def warn_fe_macro_contains_embedded_newline : Warning<
     "macro '%0' contains embedded newline, text after the newline is ignored.">;
+def warn_fe_cc_print_header_failure : Warning<
+    "unable to open CC_PRINT_HEADERS file: %0 (using stderr)">;
 
 def err_verify_missing_start : Error<
     "cannot find start ('{{') of expected %0">;

lib/Frontend/HeaderIncludeGen.cpp

@@ -9,14 +9,15 @@
 
 #include "clang/Frontend/Utils.h"
 #include "clang/Basic/SourceManager.h"
+#include "clang/Frontend/FrontendDiagnostic.h"
 #include "clang/Lex/Preprocessor.h"
-#include <cstdio>
+#include "llvm/Support/raw_ostream.h"
 using namespace clang;
 
 namespace {
 class HeaderIncludesCallback : public PPCallbacks {
   SourceManager &SM;
-  FILE *OutputFile;
+  llvm::raw_ostream *OutputFile;
   unsigned CurrentIncludeDepth;
   bool HasProcessedPredefines;
   bool OwnsOutputFile;
@@ -24,14 +25,14 @@ class HeaderIncludesCallback : public PPCallbacks {
 
 public:
   HeaderIncludesCallback(const Preprocessor *PP, bool ShowAllHeaders_,
-                         FILE *OutputFile_, bool OwnsOutputFile_)
+                         llvm::raw_ostream *OutputFile_, bool OwnsOutputFile_)
     : SM(PP->getSourceManager()), OutputFile(OutputFile_),
       CurrentIncludeDepth(0), HasProcessedPredefines(false),
       OwnsOutputFile(OwnsOutputFile_), ShowAllHeaders(ShowAllHeaders_) {}
 
   ~HeaderIncludesCallback() {
     if (OwnsOutputFile)
-      fclose(OutputFile);
+      delete OutputFile;
   }
 
   virtual void FileChanged(SourceLocation Loc, FileChangeReason Reason,
@@ -41,16 +42,24 @@ public:
 
 void clang::AttachHeaderIncludeGen(Preprocessor &PP, bool ShowAllHeaders,
                                    llvm::StringRef OutputPath) {
-  FILE *OutputFile;
-  bool OwnsOutputFile;
+  llvm::raw_ostream *OutputFile = &llvm::errs();
+  bool OwnsOutputFile = false;
 
   // Open the output file, if used.
-  if (OutputPath.empty()) {
-    OutputFile = stderr;
-    OwnsOutputFile = false;
-  } else {
-    OutputFile = fopen(OutputPath.str().c_str(), "a");
-    OwnsOutputFile = true;
+  if (!OutputPath.empty()) {
+    std::string Error;
+    llvm::raw_fd_ostream *OS = new llvm::raw_fd_ostream(
+      OutputPath.str().c_str(), Error, llvm::raw_fd_ostream::F_Append);
+    if (!Error.empty()) {
+      PP.getDiagnostics().Report(
+        clang::diag::warn_fe_cc_print_header_failure) << Error;
+      delete OS;
+    } else {
+      OS->SetUnbuffered();
+      OS->SetUseAtomicWrites(true);
+      OutputFile = OS;
+      OwnsOutputFile = true;
+    }
   }
 
   PP.addPPCallbacks(new HeaderIncludesCallback(&PP, ShowAllHeaders,
@@ -99,7 +108,6 @@ void HeaderIncludesCallback::FileChanged(SourceLocation Loc,
     Msg += Filename;
     Msg += '\n';
 
-    fwrite(Msg.data(), Msg.size(), 1, OutputFile);
+    OutputFile->write(Msg.data(), Msg.size());
   }
 }
-