Subzero: Tweaks to reduce malloc use.

src/IceBrowserCompileServer.cpp

 //===- subzero/src/IceBrowserCompileServer.cpp - Browser compile server ---===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 154 matching lines @@
 void BrowserCompileServer::getParsedFlags(uint32_t NumThreads, int argc,
                                           char **argv) {
   ClFlags::parseFlags(argc, argv);
   ClFlags::getParsedClFlags(*Flags);
   ClFlags::getParsedClFlagsExtra(*ExtraFlags);
   // Set some defaults which aren't specified via the argv string.
   Flags->setNumTranslationThreads(NumThreads);
   Flags->setUseSandboxing(true);
   Flags->setOutFileType(FT_Elf);
   Flags->setTargetArch(getTargetArch());
+  // Make the prefixes short to reduce the chance that string construction will
+  // have to resort to malloc().  Note that this won't change anything if the
+  // pexe was finalize with "--no-strip-syms".  TODO(stichnot): This will be
+  // unnecessary when we stop directly constructing strings that are used for
+  // names and lookup keys.
+  Flags->setDefaultFunctionPrefix("F");
+  Flags->setDefaultGlobalPrefix("G");
   ExtraFlags->setBuildOnRead(true);
   ExtraFlags->setInputFileFormat(llvm::PNaClFormat);
 }
 
 bool BrowserCompileServer::pushInputBytes(const void *Data, size_t NumBytes) {
   // If there was an earlier error, do not attempt to push bytes to the
   // QueueStreamer. Otherwise the thread could become blocked.
   if (HadError.load())
     return true;
   return InputStream->PutBytes(
@@ skipping 56 matching lines @@
   llvm::report_fatal_error("no browser hookups");
 }
 
 ErrorCode &BrowserCompileServer::getErrorCode() {
   llvm::report_fatal_error("no browser hookups");
 }
 
 } // end of namespace Ice
 
 #endif // PNACL_BROWSER_TRANSLATOR