From 4c4a24547561be4785ff36a1a86b87ada9a67c67 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Tue, 24 Jul 2007 06:57:14 +0000
Subject: [PATCH] Use a smallstring instead of an std::string in FileChanged to
 avoid some malloc traffic.

This speeds up -E on xalancbmk by 2.4%

llvm-svn: 40461
---
 clang/Basic/SourceManager.cpp             |  2 +-
 clang/Driver/PrintPreprocessedOutput.cpp  |  9 ++++++---
 clang/Lex/Lexer.cpp                       | 11 +++++++++++
 clang/include/clang/Basic/SourceManager.h |  2 +-
 clang/include/clang/Lex/Lexer.h           |  5 +++++
 5 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/clang/Basic/SourceManager.cpp b/clang/Basic/SourceManager.cpp
index e53547087df0..df13fad37c31 100644
--- a/clang/Basic/SourceManager.cpp
+++ b/clang/Basic/SourceManager.cpp
@@ -231,7 +231,7 @@ unsigned SourceManager::getColumnNumber(SourceLocation Loc) const {
 /// getSourceName - This method returns the name of the file or buffer that
 /// the SourceLocation specifies.  This can be modified with #line directives,
 /// etc.
-std::string SourceManager::getSourceName(SourceLocation Loc) {
+const char *SourceManager::getSourceName(SourceLocation Loc) {
   unsigned FileID = Loc.getFileID();
   if (FileID == 0) return "";
   return getFileInfo(FileID)->Buffer->getBufferIdentifier();
diff --git a/clang/Driver/PrintPreprocessedOutput.cpp b/clang/Driver/PrintPreprocessedOutput.cpp
index d5c5b9a08bb3..a8bc4e40d222 100644
--- a/clang/Driver/PrintPreprocessedOutput.cpp
+++ b/clang/Driver/PrintPreprocessedOutput.cpp
@@ -18,6 +18,7 @@
 #include "clang/Lex/Pragma.h"
 #include "clang/Basic/SourceManager.h"
 #include "llvm/Support/CommandLine.h"
+#include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/Config/config.h"
 #include <cstdio>
@@ -123,13 +124,13 @@ namespace {
 class PrintPPOutputPPCallbacks : public PPCallbacks {
   Preprocessor &PP;
   unsigned CurLine;
-  std::string CurFilename;
   bool EmittedTokensOnThisLine;
   DirectoryLookup::DirType FileType;
+  llvm::SmallString<512> CurFilename;
 public:
   PrintPPOutputPPCallbacks(Preprocessor &pp) : PP(pp) {
     CurLine = 0;
-    CurFilename = "<uninit>";
+    CurFilename += "<uninit>";
     EmittedTokensOnThisLine = false;
     FileType = DirectoryLookup::NormalHeaderDir;
   }
@@ -237,7 +238,9 @@ void PrintPPOutputPPCallbacks::FileChanged(SourceLocation Loc,
   
   Loc = SourceMgr.getLogicalLoc(Loc);
   CurLine = SourceMgr.getLineNumber(Loc);
-  CurFilename = Lexer::Stringify(SourceMgr.getSourceName(Loc));
+  CurFilename.clear();
+  CurFilename += SourceMgr.getSourceName(Loc);
+  Lexer::Stringify(CurFilename);
   FileType = FileType;
   
   if (EmittedTokensOnThisLine) {
diff --git a/clang/Lex/Lexer.cpp b/clang/Lex/Lexer.cpp
index f23d34ed422f..c45a36a9a59f 100644
--- a/clang/Lex/Lexer.cpp
+++ b/clang/Lex/Lexer.cpp
@@ -92,6 +92,17 @@ std::string Lexer::Stringify(const std::string &Str, bool Charify) {
   return Result;
 }
 
+/// Stringify - Convert the specified string into a C string by escaping '\'
+/// and " characters.  This does not add surrounding ""'s to the string.
+void Lexer::Stringify(llvm::SmallVectorImpl<char> &Str) {
+  for (unsigned i = 0, e = Str.size(); i != e; ++i) {
+    if (Str[i] == '\\' || Str[i] == '"') {
+      Str.insert(Str.begin()+i, '\\');
+      ++i; ++e;
+    }
+  }
+}
+
 
 //===----------------------------------------------------------------------===//
 // Character information.
diff --git a/clang/include/clang/Basic/SourceManager.h b/clang/include/clang/Basic/SourceManager.h
index dd8a86cc7e98..825e7dee65ab 100644
--- a/clang/include/clang/Basic/SourceManager.h
+++ b/clang/include/clang/Basic/SourceManager.h
@@ -240,7 +240,7 @@ public:
   /// getSourceName - This method returns the name of the file or buffer that
   /// the SourceLocation specifies.  This can be modified with #line directives,
   /// etc.
-  std::string getSourceName(SourceLocation Loc);
+  const char *getSourceName(SourceLocation Loc);
 
   /// Given a SourceLocation object, return the logical location referenced by
   /// the ID.  This logical location is subject to #line directives, etc.
diff --git a/clang/include/clang/Lex/Lexer.h b/clang/include/clang/Lex/Lexer.h
index 6cff00020784..18c2fca31aac 100644
--- a/clang/include/clang/Lex/Lexer.h
+++ b/clang/include/clang/Lex/Lexer.h
@@ -17,6 +17,7 @@
 #include "clang/Lex/Token.h"
 #include "clang/Lex/MultipleIncludeOpt.h"
 #include "clang/Basic/LangOptions.h"
+#include "llvm/ADT/SmallVector.h"
 #include <string>
 #include <vector>
 #include <cassert>
@@ -173,6 +174,10 @@ public:
   /// If Charify is true, this escapes the ' character instead of ".
   static std::string Stringify(const std::string &Str, bool Charify = false);
   
+  /// Stringify - Convert the specified string into a C string by escaping '\'
+  /// and " characters.  This does not add surrounding ""'s to the string.
+  static void Stringify(llvm::SmallVectorImpl<char> &Str);
+  
   //===--------------------------------------------------------------------===//
   // Internal implementation interfaces.
 private: