[llvm-commits] CVS: llvm/lib/VMCore/Type.cpp

[Chris Lattner]

Changes in directory llvm/lib/VMCore:

Type.cpp updated: 1.69 -> 1.70

---
Log message:

Make the PATypeHolder use a simple union-find implementation to handle
merging of types.  This makes it MUCH more efficient than before, also
making things simpler.


---
Diffs of the changes:

Index: llvm/lib/VMCore/Type.cpp
diff -u llvm/lib/VMCore/Type.cpp:1.69 llvm/lib/VMCore/Type.cpp:1.70
--- llvm/lib/VMCore/Type.cpp:1.69	Wed Sep 10 00:29:06 2003
+++ llvm/lib/VMCore/Type.cpp	Thu Oct  2 18:35:57 2003
@@ -32,13 +32,8 @@
 static std::map<const Type*, std::string> ConcreteTypeDescriptions;
 static std::map<const Type*, std::string> AbstractTypeDescriptions;
 
-void PATypeHolder::dump() const {
-  std::cerr << "PATypeHolder(" << (void*)this << ")\n";
-}
-
-
 Type::Type(const std::string &name, PrimitiveID id)
-  : Value(Type::TypeTy, Value::TypeVal) {
+  : Value(Type::TypeTy, Value::TypeVal), ForwardType(0) {
   if (!name.empty())
     ConcreteTypeDescriptions[this] = name;
   ID = id;
@@ -122,6 +117,30 @@
 }
 
 
+/// getForwardedTypeInternal - This method is used to implement the union-find
+/// algorithm for when a type is being forwarded to another type.
+const Type *Type::getForwardedTypeInternal() const {
+  assert(ForwardType && "This type is not being forwarded to another type!");
+  
+  // Check to see if the forwarded type has been forwarded on.  If so, collapse
+  // the forwarding links.
+  const Type *RealForwardedType = ForwardType->getForwardedType();
+  if (!RealForwardedType)
+    return ForwardType;  // No it's not forwarded again
+
+  // Yes, it is forwarded again.  First thing, add the reference to the new
+  // forward type.
+  if (RealForwardedType->isAbstract())
+    cast<DerivedType>(RealForwardedType)->addRef();
+
+  // Now drop the old reference.  This could cause ForwardType to get deleted.
+  cast<DerivedType>(ForwardType)->dropRef();
+  
+  // Return the updated type.
+  ForwardType = RealForwardedType;
+  return ForwardType;
+}
+
 // getTypeDescription - This is a recursive function that walks a type hierarchy
 // calculating the description for a type.
 //
@@ -950,21 +969,6 @@
 //                     Derived Type Refinement Functions
 //===----------------------------------------------------------------------===//
 
-// addAbstractTypeUser - Notify an abstract type that there is a new user of
-// it.  This function is called primarily by the PATypeHandle class.
-//
-void DerivedType::addAbstractTypeUser(AbstractTypeUser *U) const {
-  assert(isAbstract() && "addAbstractTypeUser: Current type not abstract!");
-
-#if DEBUG_MERGE_TYPES
-  std::cerr << "  addAbstractTypeUser[" << (void*)this << ", "
-            << *this << "][" << AbstractTypeUsers.size()
-            << "] User = " << U << "\n";
-#endif
-  AbstractTypeUsers.push_back(U);
-}
-
-
 // removeAbstractTypeUser - Notify an abstract type that a user of the class
 // no longer has a handle to the type.  This function is called primarily by
 // the PATypeHandle class.  When there are no users of the abstract type, it
@@ -989,7 +993,7 @@
             << *this << "][" << i << "] User = " << U << "\n";
 #endif
     
-  if (AbstractTypeUsers.empty() && isAbstract()) {
+  if (AbstractTypeUsers.empty() && RefCount == 0 && isAbstract()) {
 #ifdef DEBUG_MERGE_TYPES
     std::cerr << "DELETEing unused abstract type: <" << *this
               << ">[" << (void*)this << "]" << "\n";
@@ -1022,6 +1026,10 @@
   // refined, that we will not continue using a dead reference...
   //
   PATypeHolder NewTy(NewType);
+
+  ForwardType = NewType;
+  if (NewType->isAbstract())
+    cast<DerivedType>(NewType)->addRef();
 
   // Add a self use of the current type so that we don't delete ourself until
   // after this while loop.  We are careful to never invoke refine on ourself,