From fa0cdd6234aa73ab0680c37f23664ff8c73cc1cb Mon Sep 17 00:00:00 2001
From: David Robillard <d@drobilla.net>
Date: Sat, 20 Jun 2009 06:08:23 +0000
Subject: Garbage collection of code-allocated stack frames.

git-svn-id: http://svn.drobilla.net/resp/tuplr@130 ad02d1e2-f140-0410-9f75-f8b11f17cedd
---
 llvm.cpp | 41 ++++++++++++++++++++++++++---------------
 1 file changed, 26 insertions(+), 15 deletions(-)

(limited to 'llvm.cpp')

diff --git a/llvm.cpp b/llvm.cpp
index 85e4a14..80aaafb 100644
--- a/llvm.cpp
+++ b/llvm.cpp
@@ -241,11 +241,16 @@ AClosure::liftCall(CEnv& cenv, const AType& argsT)
 
 	ATuple* protT = thisType->at(1)->as<ATuple*>();
 
+	vector<string> argNames;
+	for (size_t i = 0; i < prot()->size(); ++i) {
+		argNames.push_back(prot()->at(i)->str());
+	}
+
 	// Write function declaration
 	const string name = (this->name == "") ? cenv.gensym("_fn") : this->name;
 	Function* f = compileFunction(cenv, name,
 			lltype(thisType->at(thisType->size()-1)->to<AType*>()),
-			*protT, loc);
+			*protT, loc, argNames);
 
 	llvm::IRBuilder<>& builder = llengine(cenv)->builder;
 
@@ -253,12 +258,13 @@ AClosure::liftCall(CEnv& cenv, const AType& argsT)
 	Subst oldSubst = cenv.tsubst;
 	cenv.tsubst = Subst::compose(cenv.tsubst, Subst::compose(argsSubst, subst));
 
-//#define EXPLICIT_STACK_FRAME 1
+//#define EXPLICIT_STACK_FRAMES 1
 
 #ifdef EXPLICIT_STACK_FRAMES
 	vector<const Type*> types;
-	types.push_back(PointerType::get(Type::VoidTy, 0));
-	size_t s = 0;
+	types.push_back(Type::Int8Ty);
+	types.push_back(Type::Int8Ty);
+	size_t s = 16; // stack frame size in bits
 #endif
 
 	// Bind argument values in CEnv
@@ -290,16 +296,20 @@ AClosure::liftCall(CEnv& cenv, const AType& argsT)
 	}
 
 	// Create stack frame
-	StructType* sT = StructType::get(types, false);
-	PointerType* pT = PointerType::get(sT, 0);
-	Value* frameSize = ConstantInt::get(Type::Int32Ty, (s + pT->getPrimitiveSizeInBits()) / 8);
-	Value* mem = builder.CreateCall(LLVal(cenv.alloc), frameSize, "mem");
-	Value* frame = builder.CreateBitCast(mem, pT, "frame");
+	StructType*  frameT    = StructType::get(types, false);
+	PointerType* framePtrT = PointerType::get(frameT, 0);
+
+	Value* tag = ConstantInt::get(Type::Int8Ty, (uint8_t)GC::TAG_FRAME);
+
+	Value* frameSize = ConstantInt::get(Type::Int32Ty, s / 8);
+	Value* frame     = builder.CreateCall2(LLVal(cenv.alloc), frameSize, tag, "frame");
+
+	Value* framePtr  = builder.CreateBitCast(frame, framePtrT, "frameptr");
 
 	// Bind parameter values in stack frame
-	i = 1;
+	i = 2;
 	for (Function::arg_iterator a = f->arg_begin(); a != f->arg_end(); ++a, ++i) {
-		Value* v = builder.CreateStructGEP(frame, i);
+		Value* v = builder.CreateStructGEP(framePtr, i, "arg");
 		builder.CreateStore(&*a, v);
 	}
 #endif
@@ -550,7 +560,7 @@ eval(CEnv& cenv, const string& name, istream& is)
 		cenv.out << call(resultType, llengine(cenv)->engine->getPointerToFunction(f))
 		    << " : " << resultType << endl;
 
-		Object::pool.collect(cenv, Object::pool.roots());
+		Object::pool.collect(Object::pool.roots());
 
 		if (cenv.args.find("-d") != cenv.args.end())
 			cenv.write(cenv.out);
@@ -608,7 +618,7 @@ repl(CEnv& cenv)
 			if (body->to<ADefinition*>())
 				cenv.lock(body);
 
-			Object::pool.collect(cenv, Object::pool.roots());
+			Object::pool.collect(Object::pool.roots());
 
 			cenv.tsubst = oldSubst;
 			if (cenv.args.find("-d") != cenv.args.end())
@@ -628,7 +638,8 @@ newCenv(PEnv& penv, TEnv& tenv)
 	CEnv*       cenv   = new CEnv(penv, tenv, engine);
 
 	// Host provided allocation primitive prototypes
-	std::vector<const Type*> argsT(1, Type::Int32Ty);
+	std::vector<const Type*> argsT(1, Type::Int32Ty); // size
+	argsT.push_back(Type::Int8Ty); // tag
 	FunctionType* funcT = FunctionType::get(PointerType::get(Type::Int8Ty, 0), argsT, false);
 	cenv->alloc = Function::Create(funcT, Function::ExternalLinkage,
 			"tuplr_gc_allocate", engine->module);
@@ -639,7 +650,7 @@ newCenv(PEnv& penv, TEnv& tenv)
 void
 freeCenv(CEnv* cenv)
 {
-	Object::pool.collect(*cenv, ::GC::Roots());
+	Object::pool.collect(GC::Roots());
 	delete (LLVMEngine*)cenv->engine();
 	delete cenv;
 }
-- 
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