DwarfDebug: Allocate DIEValues with a BumpPtrAllocator. Most of them are
POD-like anyway, so we don't even care about calling their d'tors (DIEBlock
being the exception).

~6% less mallocs and ~1% compile time improvement on clang -O0 -g oggenc.c



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100035 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.h b/lib/CodeGen/AsmPrinter/DwarfDebug.h
index 5ab2a0c..ad6b0c2 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -19,6 +19,7 @@
 #include "llvm/CodeGen/AsmPrinter.h"
 #include "llvm/CodeGen/MachineLocation.h"
 #include "llvm/Analysis/DebugInfo.h"
+#include "llvm/Support/Allocator.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/FoldingSet.h"
@@ -98,9 +99,11 @@
   /// Lines - List of source line correspondence.
   std::vector<SrcLineInfo> Lines;
 
-  /// DIEValues - A list of all the unique values in use.
-  ///
-  std::vector<DIEValue *> DIEValues;
+  /// DIEBlocks - A list of all the DIEBlocks in use.
+  std::vector<DIEBlock *> DIEBlocks;
+
+  // DIEValueAllocator - All DIEValues are allocated through this allocator.
+  BumpPtrAllocator DIEValueAllocator;
 
   /// StringPool - A String->Symbol mapping of strings used by indirect
   /// references.