make the token lexer allocate its temporary token buffers for
preexpanded macro arguments from the preprocessor's bump pointer.
This reduces # mallocs from 12444 to 11792.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@66025 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/Lex/Preprocessor.h b/include/clang/Lex/Preprocessor.h
index ae7d3b6..4f5def5 100644
--- a/include/clang/Lex/Preprocessor.h
+++ b/include/clang/Lex/Preprocessor.h
@@ -205,6 +205,8 @@
 
   IdentifierTable &getIdentifierTable() { return Identifiers; }
   SelectorTable &getSelectorTable() { return Selectors; }
+  llvm::BumpPtrAllocator &getPreprocessorAllocator() { return BP; }
+  
   
   void setPTHManager(PTHManager* pm);
 
diff --git a/include/clang/Lex/TokenLexer.h b/include/clang/Lex/TokenLexer.h
index a3004b1..c0a61cf 100644
--- a/include/clang/Lex/TokenLexer.h
+++ b/include/clang/Lex/TokenLexer.h
@@ -42,7 +42,10 @@
 
   /// Tokens - This is the pointer to an array of tokens that the macro is
   /// defined to, with arguments expanded for function-like macros.  If this is
-  /// a token stream, these are the tokens we are returning.
+  /// a token stream, these are the tokens we are returning.  This points into
+  /// the macro definition we are lexing from, a scratch buffer allocated from
+  /// the preprocessor's bump pointer allocator, or some other buffer that we
+  /// may or may not own (depending on OwnsTokens).
   const Token *Tokens;
   
   /// NumTokens - This is the length of the Tokens array.
diff --git a/lib/Lex/TokenLexer.cpp b/lib/Lex/TokenLexer.cpp
index f0e2fbd..898b3a7 100644
--- a/lib/Lex/TokenLexer.cpp
+++ b/lib/Lex/TokenLexer.cpp
@@ -88,6 +88,7 @@
   if (OwnsTokens) {
     delete [] Tokens;
     Tokens = 0;
+    OwnsTokens = false;
   }
   
   // TokenLexer owns its formal arguments.
@@ -264,13 +265,19 @@
   
   // If anything changed, install this as the new Tokens list.
   if (MadeChange) {
+    assert(!OwnsTokens && "This would leak if we already own the token list");
     // This is deleted in the dtor.
     NumTokens = ResultToks.size();
-    Token *Res = new Token[ResultToks.size()];
+    llvm::BumpPtrAllocator &Alloc = PP.getPreprocessorAllocator();
+    Token *Res =
+      static_cast<Token *>(Alloc.Allocate(sizeof(Token)*ResultToks.size(),
+                                          llvm::alignof<Token>()));
     if (NumTokens)
       memcpy(Res, &ResultToks[0], NumTokens*sizeof(Token));
     Tokens = Res;
-    OwnsTokens = true;
+    
+    // The preprocessor bump pointer owns these tokens, not us.
+    OwnsTokens = false;
   }
 }