Refactor SymbolTableListTraits to only have a single pointer in it, instead

of two.  This shrinkifies Function by 8 bytes (104->96) and Module by 8
bytes (68->60).  On a testcase of mine, this reduces the memory used to
read a module header from 565680b to 561024, a little over 4K.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36188 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 77 insertions, 59 deletions

diff --git a/lib/VMCore/BasicBlock.cpp b/lib/VMCore/BasicBlock.cpp
index 2e3b426e2b..e10948e2ad 100644
--- a/lib/VMCore/BasicBlock.cpp
+++ b/lib/VMCore/BasicBlock.cpp
@@ -22,6 +22,15 @@
 #include <algorithm>
 using namespace llvm;
 
+inline ValueSymbolTable *
+ilist_traits<Instruction>::getSymTab(BasicBlock *BB) {
+  if (BB)
+    if (Function *F = BB->getParent())
+      return &F->getValueSymbolTable();
+  return 0;
+}
+
+
 namespace {
   /// DummyInst - An instance of this class is used to mark the end of the
   /// instruction list.  This is not a real instruction.
@@ -57,24 +66,24 @@ iplist<Instruction> &ilist_traits<Instruction>::getList(BasicBlock *BB) {
 
 // Explicit instantiation of SymbolTableListTraits since some of the methods
 // are not in the public header file...
-template class SymbolTableListTraits<Instruction, BasicBlock, Function>;
+template class SymbolTableListTraits<Instruction, BasicBlock>;
 
 
-BasicBlock::BasicBlock(const std::string &Name, Function *Parent,
+BasicBlock::BasicBlock(const std::string &Name, Function *NewParent,
                        BasicBlock *InsertBefore)
-  : Value(Type::LabelTy, Value::BasicBlockVal) {
-  // Initialize the instlist...
+  : Value(Type::LabelTy, Value::BasicBlockVal), Parent(0) {
+  // Initialize the instlist.
   InstList.setItemParent(this);
 
   // Make sure that we get added to a function
   LeakDetector::addGarbageObject(this);
 
   if (InsertBefore) {
-    assert(Parent &&
+    assert(NewParent &&
            "Cannot insert block before another block with no function!");
-    Parent->getBasicBlockList().insert(InsertBefore, this);
-  } else if (Parent) {
-    Parent->getBasicBlockList().push_back(this);
+    NewParent->getBasicBlockList().insert(InsertBefore, this);
+  } else if (NewParent) {
+    NewParent->getBasicBlockList().push_back(this);
   }
   
   setName(Name);
@@ -91,7 +100,8 @@ void BasicBlock::setParent(Function *parent) {
   if (getParent())
     LeakDetector::addGarbageObject(this);
 
-  InstList.setParent(parent);
+  // Set Parent=parent, updating instruction symtab entries as appropriate.
+  InstList.setSymTabObject(&Parent, parent);
 
   if (getParent())
     LeakDetector::removeGarbageObject(this);
diff --git a/lib/VMCore/Function.cpp b/lib/VMCore/Function.cpp
index edce58d6aa..7949e39f84 100644
--- a/lib/VMCore/Function.cpp
+++ b/lib/VMCore/Function.cpp
@@ -44,8 +44,8 @@ iplist<Argument> &ilist_traits<Argument>::getList(Function *F) {
 
 // Explicit instantiations of SymbolTableListTraits since some of the methods
 // are not in the public header file...
-template class SymbolTableListTraits<Argument, Function, Function>;
-template class SymbolTableListTraits<BasicBlock, Function, Function>;
+template class SymbolTableListTraits<Argument, Function>;
+template class SymbolTableListTraits<BasicBlock, Function>;
 
 //===----------------------------------------------------------------------===//
 // Argument Implementation
@@ -144,9 +144,7 @@ Function::Function(const FunctionType *Ty, LinkageTypes Linkage,
   ParamAttrs = 0;
   CallingConvention = 0;
   BasicBlocks.setItemParent(this);
-  BasicBlocks.setParent(this);
   ArgumentList.setItemParent(this);
-  ArgumentList.setParent(this);
   SymTab = new ValueSymbolTable();
 
   assert((getReturnType()->isFirstClassType() ||getReturnType() == Type::VoidTy)
@@ -171,7 +169,6 @@ Function::~Function() {
 
   // Delete all of the method arguments and unlink from symbol table...
   ArgumentList.clear();
-  ArgumentList.setParent(0);
   delete SymTab;
 }
 
diff --git a/lib/VMCore/Module.cpp b/lib/VMCore/Module.cpp
index 016ab16ff5..465cb69445 100644
--- a/lib/VMCore/Module.cpp
+++ b/lib/VMCore/Module.cpp
@@ -55,8 +55,8 @@ iplist<GlobalVariable> &ilist_traits<GlobalVariable>::getList(Module *M) {
 
 // Explicit instantiations of SymbolTableListTraits since some of the methods
 // are not in the public header file.
-template class SymbolTableListTraits<GlobalVariable, Module, Module>;
-template class SymbolTableListTraits<Function, Module, Module>;
+template class SymbolTableListTraits<GlobalVariable, Module>;
+template class SymbolTableListTraits<Function, Module>;
 
 //===----------------------------------------------------------------------===//
 // Primitive Module methods.
@@ -65,9 +65,7 @@ template class SymbolTableListTraits<Function, Module, Module>;
 Module::Module(const std::string &MID)
   : ModuleID(MID), DataLayout("") {
   FunctionList.setItemParent(this);
-  FunctionList.setParent(this);
   GlobalList.setItemParent(this);
-  GlobalList.setParent(this);
   ValSymTab = new ValueSymbolTable();
   TypeSymTab = new TypeSymbolTable();
 }
@@ -75,9 +73,7 @@ Module::Module(const std::string &MID)
 Module::~Module() {
   dropAllReferences();
   GlobalList.clear();
-  GlobalList.setParent(0);
   FunctionList.clear();
-  FunctionList.setParent(0);
   LibraryList.clear();
   delete ValSymTab;
   delete TypeSymTab;
diff --git a/lib/VMCore/SymbolTableListTraitsImpl.h b/lib/VMCore/SymbolTableListTraitsImpl.h
index 9c3d2525cf..ce2c0c0cc7 100644
--- a/lib/VMCore/SymbolTableListTraitsImpl.h
+++ b/lib/VMCore/SymbolTableListTraitsImpl.h
@@ -21,53 +21,68 @@
 
 namespace llvm {
 
-template<typename ValueSubClass, typename ItemParentClass,typename SymTabClass,
-         typename SubClass>
-void SymbolTableListTraits<ValueSubClass,ItemParentClass,SymTabClass,SubClass>
-::setParent(SymTabClass *STO) {
-  iplist<ValueSubClass> &List = SubClass::getList(ItemParent);
+/// setSymTabObject - This is called when (f.e.) the parent of a basic block
+/// changes.  This requires us to remove all the instruction symtab entries from
+/// the current function and reinsert them into the new function.
+template<typename ValueSubClass, typename ItemParentClass>
+template<typename TPtr>
+void SymbolTableListTraits<ValueSubClass,ItemParentClass>
+::setSymTabObject(TPtr *Dest, TPtr Src) {
+  // Get the old symtab and value list before doing the assignment.
+  ValueSymbolTable *OldST = TraitsClass::getSymTab(ItemParent);
 
-  // Remove all of the items from the old symtab..
-  if (SymTabObject && !List.empty()) {
-    ValueSymbolTable &SymTab = SymTabObject->getValueSymbolTable();
-    for (typename iplist<ValueSubClass>::iterator I = List.begin();
-         I != List.end(); ++I)
-      if (I->hasName()) SymTab.removeValueName(I->getValueName());
+  // Do it.
+  *Dest = Src;
+  
+  // Get the new SymTab object.
+  ValueSymbolTable *NewST = TraitsClass::getSymTab(ItemParent);
+  
+  // If there is nothing to do, quick exit.
+  if (OldST == NewST) return;
+  
+  // Move all the elements from the old symtab to the new one.
+  iplist<ValueSubClass> &ItemList = TraitsClass::getList(ItemParent);
+  if (ItemList.empty()) return;
+  
+  if (OldST) {
+    // Remove all entries from the previous symtab.
+    for (typename iplist<ValueSubClass>::iterator I = ItemList.begin();
+         I != ItemList.end(); ++I)
+      if (I->hasName())
+        OldST->removeValueName(I->getValueName());
   }
 
-  SymTabObject = STO;
-
-  // Add all of the items to the new symtab...
-  if (SymTabObject && !List.empty()) {
-    ValueSymbolTable &SymTab = SymTabObject->getValueSymbolTable();
-    for (typename iplist<ValueSubClass>::iterator I = List.begin();
-         I != List.end(); ++I)
-      if (I->hasName()) SymTab.reinsertValue(I);
+  if (NewST) {
+    // Add all of the items to the new symtab.
+    for (typename iplist<ValueSubClass>::iterator I = ItemList.begin();
+         I != ItemList.end(); ++I)
+      if (I->hasName())
+        NewST->reinsertValue(I);
   }
+  
 }
 
-template<typename ValueSubClass, typename ItemParentClass, typename SymTabClass,
-         typename SubClass>
-void SymbolTableListTraits<ValueSubClass,ItemParentClass,SymTabClass,SubClass>
+template<typename ValueSubClass, typename ItemParentClass>
+void SymbolTableListTraits<ValueSubClass,ItemParentClass>
 ::addNodeToList(ValueSubClass *V) {
   assert(V->getParent() == 0 && "Value already in a container!!");
   V->setParent(ItemParent);
-  if (V->hasName() && SymTabObject)
-    SymTabObject->getValueSymbolTable().reinsertValue(V);
+  if (V->hasName())
+    if (ValueSymbolTable *ST = TraitsClass::getSymTab(ItemParent))
+      ST->reinsertValue(V);
 }
 
-template<typename ValueSubClass, typename ItemParentClass, typename SymTabClass,
-         typename SubClass>
-void SymbolTableListTraits<ValueSubClass,ItemParentClass,SymTabClass,SubClass>
+template<typename ValueSubClass, typename ItemParentClass>
+void SymbolTableListTraits<ValueSubClass,ItemParentClass>
 ::removeNodeFromList(ValueSubClass *V) {
   V->setParent(0);
-  if (V->hasName() && SymTabObject)
-    SymTabObject->getValueSymbolTable().removeValueName(V->getValueName());
+  if (V->hasName())
+    if (ValueSymbolTable *ST = TraitsClass::getSymTab(ItemParent))
+      ST->removeValueName(V->getValueName());
 }
 
-template<typename ValueSubClass, typename ItemParentClass, typename SymTabClass,
-         typename SubClass>
-void SymbolTableListTraits<ValueSubClass,ItemParentClass,SymTabClass,SubClass>
+template<typename ValueSubClass, typename ItemParentClass>
+void SymbolTableListTraits<ValueSubClass,ItemParentClass>
 ::transferNodesFromList(iplist<ValueSubClass, ilist_traits<ValueSubClass> > &L2,
                         ilist_iterator<ValueSubClass> first,
                         ilist_iterator<ValueSubClass> last) {
@@ -77,16 +92,17 @@ void SymbolTableListTraits<ValueSubClass,ItemParentClass,SymTabClass,SubClass>
 
   // We only have to update symbol table entries if we are transferring the
   // instructions to a different symtab object...
-  SymTabClass *NewSTO = SymTabObject, *OldSTO = L2.SymTabObject;
-  if (NewSTO != OldSTO) {
+  ValueSymbolTable *NewST = TraitsClass::getSymTab(ItemParent);
+  ValueSymbolTable *OldST = TraitsClass::getSymTab(OldIP);
+  if (NewST != OldST) {
     for (; first != last; ++first) {
       ValueSubClass &V = *first;
       bool HasName = V.hasName();
-      if (OldSTO && HasName)
-        OldSTO->getValueSymbolTable().removeValueName(V.getValueName());
+      if (OldST && HasName)
+        OldST->removeValueName(V.getValueName());
       V.setParent(NewIP);
-      if (NewSTO && HasName)
-        NewSTO->getValueSymbolTable().reinsertValue(&V);
+      if (NewST && HasName)
+        NewST->reinsertValue(&V);
     }
   } else {
     // Just transferring between blocks in the same function, simply update the
diff --git a/lib/VMCore/Type.cpp b/lib/VMCore/Type.cpp
index 10063126e5..e4c89f182a 100644
--- a/lib/VMCore/Type.cpp
+++ b/lib/VMCore/Type.cpp
@@ -433,7 +433,6 @@ FunctionType::FunctionType(const Type *Result,
 
   // Calculate whether or not this type is abstract
   setAbstract(isAbstract);
-
 }
 
 StructType::StructType(const std::vector<const Type*> &Types, bool isPacked)