[llvm-commits] [llvm] r65776 - in /llvm/trunk: include/llvm/Function.h lib/VMCore/Function.cpp

[Gabor Greif]

Author: ggreif
Date: Sun Mar  1 10:38:10 2009
New Revision: 65776

URL: http://llvm.org/viewvc/llvm-project?rev=65776&view=rev
Log:
Reuse a technique (pioneered for BasicBlocks) of superposing ilist with
its sentinel. This is quite a win when a function really has a basic block.                  
When the function is just a declaration (and stays so) the old way did not
allocate a sentinel. So this change is most beneficial when the ratio of
function definition to declaration is high. I.e. linkers etc. Incidentally  
these are the most resource demanding applications, so I expect that the
reduced malloc traffic, locality and space savings outweigh the cost of
addition of two pointers to Function.

Modified:
    llvm/trunk/include/llvm/Function.h
    llvm/trunk/lib/VMCore/Function.cpp

Modified: llvm/trunk/include/llvm/Function.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Function.h?rev=65776&r1=65775&r2=65776&view=diff

==============================================================================
--- llvm/trunk/include/llvm/Function.h (original)
+++ llvm/trunk/include/llvm/Function.h Sun Mar  1 10:38:10 2009
@@ -32,12 +32,17 @@
 template<> struct ilist_traits<BasicBlock>
   : public SymbolTableListTraits<BasicBlock, Function> {
 
-  // createSentinel is used to create a node that marks the end of the list...
-  static BasicBlock *createSentinel();
-  static void destroySentinel(BasicBlock *BB) { delete BB; }
+  // createSentinel is used to get hold of the node that marks the end of the
+  // list... (same trick used here as in ilist_traits<Instruction>)
+  BasicBlock *createSentinel() const {
+    return const_cast<BasicBlock*>(static_cast<const BasicBlock*>(&Sentinel));
+  }
+  static void destroySentinel(BasicBlock*) {}
   static iplist<BasicBlock> &getList(Function *F);
   static ValueSymbolTable *getSymTab(Function *ItemParent);
   static int getListOffset();
+private:
+  ilist_node<BasicBlock> Sentinel;
 };
 
 template<> struct ilist_traits<Argument>

Modified: llvm/trunk/lib/VMCore/Function.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/VMCore/Function.cpp?rev=65776&r1=65775&r2=65776&view=diff

==============================================================================
--- llvm/trunk/lib/VMCore/Function.cpp (original)
+++ llvm/trunk/lib/VMCore/Function.cpp Sun Mar  1 10:38:10 2009
@@ -22,13 +22,6 @@
 #include "llvm/ADT/StringExtras.h"
 using namespace llvm;
 
-BasicBlock *ilist_traits<BasicBlock>::createSentinel() {
-  BasicBlock *Ret = BasicBlock::Create();
-  // This should not be garbage monitored.
-  LeakDetector::removeGarbageObject(Ret);
-  return Ret;
-}
-
 iplist<BasicBlock> &ilist_traits<BasicBlock>::getList(Function *F) {
   return F->getBasicBlockList();
 }