[cfe-commits] r111983 - in /cfe/trunk: include/clang/Driver/CC1Options.td include/clang/Frontend/PreprocessorOutputOptions.h lib/Driver/Tools.cpp lib/Frontend/CompilerInvocation.cpp lib/Frontend/PrintPreprocessedOutput.cpp test/Frontend/Inputs/ t

[Daniel Dunbar]

On Tue, Sep 7, 2010 at 6:03 PM,  <dawn at burble.org> wrote:
> I would like to see a more general solution that all of clang can
> beneefit from.  Are we planning to live with llvm::errs()'s "horrible
> buffering behavior" forever?  If not, it would be good to encapsulate
> work-arounds like this SmallString use so that all parts of the compiler
> will benefit, and it will be easy to undo later.  At a minimum, I would like
> to see a comment explaining why the SmallString buffer was used here.

Added a comment in r113379.

 - Daniel

> Thanks!
> -Dawn
>
> On Sat, Sep 04, 2010 at 01:57:46PM -0700, Daniel Dunbar wrote:
>> On Fri, Sep 3, 2010 at 9:49 AM, Chris Lattner <clattner at apple.com> wrote:
>> >
>> > On Aug 24, 2010, at 3:44 PM, Daniel Dunbar wrote:
>> >
>> >> +  // Dump the header include information, if enabled and we are past the
>> >> +  // predefines buffer.
>> >> +  if (DumpHeaderIncludes && HasProcessedPredefines &&
>> >> +      Reason == PPCallbacks::EnterFile) {
>> >> +    llvm::SmallString<256> Msg;
>> >> +    llvm::raw_svector_ostream OS(Msg);
>> >> +    for (unsigned i = 0; i != CurrentIncludeDepth; ++i)
>> >> +      OS << '.';
>> >> +    OS << ' ' << CurFilename << '\n';
>> >> +    llvm::errs() << OS.str();
>> >
>> > Why the temporary SmallString?
>>
>> It writes on llvm::errs() directly, which has horrible buffering
>> behavior. I didn't want to be flushing out one character at a time. A
>> generally solution to this problem would make more sense, but there
>> aren't so many places that output substantial text to stderr.
>>
>>  - Daniel
>>
>> > -Chris
>> >
>> >
>>
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>