Compute the argument list as lazily as possible. This ensures that clients

that don't use it don't have to pay the memory cost for the arguments.  This
allows us to avoid creating Argument nodes for many prototypes and for clients
who lazily deserialize code from a bytecode file.

llvm-svn: 41166

1 files changed, 24 insertions, 7 deletions

diff --git a/llvm/lib/VMCore/Function.cpp b/llvm/lib/VMCore/Function.cpp
index 1374d55e7d9..04541dfbfdc 100644
--- a/llvm/lib/VMCore/Function.cpp
+++ b/llvm/lib/VMCore/Function.cpp
@@ -152,13 +152,10 @@ Function::Function(const FunctionType *Ty, LinkageTypes Linkage,
   assert((getReturnType()->isFirstClassType() ||getReturnType() == Type::VoidTy)
          && "LLVM functions cannot return aggregate values!");
 
-  // Create the arguments vector, all arguments start out unnamed.
-  for (unsigned i = 0, e = Ty->getNumParams(); i != e; ++i) {
-    assert(Ty->getParamType(i) != Type::VoidTy &&
-           "Cannot have void typed arguments!");
-    ArgumentList.push_back(new Argument(Ty->getParamType(i)));
-  }
-
+  // If the function has arguments, mark them as lazily built.
+  if (Ty->getNumParams())
+    SubclassData = 1;   // Set the "has lazy arguments" bit.
+  
   // Make sure that we get added to a function
   LeakDetector::addGarbageObject(this);
 
@@ -178,6 +175,26 @@ Function::~Function() {
     ParamAttrs->dropRef();
 }
 
+void Function::BuildLazyArguments() const {
+  // Create the arguments vector, all arguments start out unnamed.
+  const FunctionType *FT = getFunctionType();
+  for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i) {
+    assert(FT->getParamType(i) != Type::VoidTy &&
+           "Cannot have void typed arguments!");
+    ArgumentList.push_back(new Argument(FT->getParamType(i)));
+  }
+  
+  // Clear the lazy arguments bit.
+  const_cast<Function*>(this)->SubclassData &= ~1;
+}
+
+size_t Function::arg_size() const {
+  return getFunctionType()->getNumParams();
+}
+bool Function::arg_empty() const {
+  return getFunctionType()->getNumParams() == 0;
+}
+
 void Function::setParent(Module *parent) {
   if (getParent())
     LeakDetector::addGarbageObject(this);