view gen/functions.cpp @ 1083:c1e9f612e2e2

Fix for dual operand form of fistp, also make reg ST(0) explicit and fix lindquists previous code that allowed dual operand form of fstp but dissallowed the single operand form accidently
author Kelly Wilson <wilsonk cpsc.ucalgary.ca>
date Tue, 10 Mar 2009 06:23:26 -0600
parents 802d508f66f1
children 4c20fcc4252b
line wrap: on
line source

#include "gen/llvm.h"
#include "llvm/Support/CFG.h"
#include "llvm/Intrinsics.h"

#include "mtype.h"
#include "aggregate.h"
#include "init.h"
#include "declaration.h"
#include "template.h"
#include "module.h"
#include "statement.h"

#include "gen/irstate.h"
#include "gen/tollvm.h"
#include "gen/llvmhelpers.h"
#include "gen/runtime.h"
#include "gen/arrays.h"
#include "gen/logger.h"
#include "gen/functions.h"
#include "gen/todebug.h"
#include "gen/classes.h"
#include "gen/dvalue.h"
#include "gen/abi.h"

const llvm::FunctionType* DtoFunctionType(Type* type, Type* thistype, Type* nesttype, bool ismain)
{
    if (Logger::enabled())
        Logger::println("DtoFunctionType(%s)", type->toChars());
    LOG_SCOPE
    // sanity check
    assert(type->ty == Tfunction);
    TypeFunction* f = (TypeFunction*)type;

    // already built ?
    if (type->ir.type != NULL) {
        //assert(f->fty != NULL);
        return llvm::cast<llvm::FunctionType>(type->ir.type->get());
    }

    if (f->linkage != LINKintrinsic) {
        // Tell the ABI we're resolving a new function type
        gABI->newFunctionType(f);
    }

    // start new ir funcTy
    f->fty.reset();

    // llvm idx counter
    size_t lidx = 0;

    // main needs a little special handling
    if (ismain)
    {
        f->fty.ret = new IrFuncTyArg(Type::tint32, false);
    }
    // sane return value
    else
    {
        Type* rt = f->next;
        unsigned a = 0;
        // sret return
        if (f->linkage != LINKintrinsic)
            if (gABI->returnInArg(f))
            {
                f->fty.arg_sret = new IrFuncTyArg(rt, true, llvm::Attribute::StructRet);
                rt = Type::tvoid;
                lidx++;
            }
            // sext/zext return
            else if (unsigned se = DtoShouldExtend(rt))
            {
                a = se;
            }
        f->fty.ret = new IrFuncTyArg(rt, false, a);
    }
    lidx++;

    // member functions
    if (thistype)
    {
        bool toref = (thistype->toBasetype()->ty == Tstruct);
        f->fty.arg_this = new IrFuncTyArg(thistype, toref);
        lidx++;
    }

    // and nested functions
    else if (nesttype)
    {
        f->fty.arg_nest = new IrFuncTyArg(nesttype, false);
        lidx++;
    }

    // vararg functions are special too
    if (f->varargs)
    {
        if (f->linkage == LINKd)
        {
            // d style with hidden args
            // 2 (array) is handled by the frontend
            if (f->varargs == 1)
            {
                // _arguments
                f->fty.arg_arguments = new IrFuncTyArg(Type::typeinfo->type->arrayOf(), false);
                lidx++;
                // _argptr
                f->fty.arg_argptr = new IrFuncTyArg(Type::tvoid->pointerTo(), false);
                lidx++;
            }
        }
        else if (f->linkage == LINKc)
        {
            f->fty.c_vararg = true;
        }
        else
        {
            type->error(0, "invalid linkage for variadic function");
            fatal();
        }
    }

    // if this _Dmain() doesn't have an argument, we force it to have one
    int nargs = Argument::dim(f->parameters);

    if (ismain && nargs == 0)
    {
        Type* mainargs = Type::tchar->arrayOf()->arrayOf();
        f->fty.args.push_back(new IrFuncTyArg(mainargs, false));
        lidx++;
    }
    // add explicit parameters
    else for (int i = 0; i < nargs; i++)
    {
        // get argument
        Argument* arg = Argument::getNth(f->parameters, i);

        // reference semantics? ref, out and static arrays are
        bool byref = (arg->storageClass & (STCref|STCout)) || (arg->type->toBasetype()->ty == Tsarray);

        Type* argtype = arg->type;
        unsigned a = 0;

        // handle lazy args
        if (arg->storageClass & STClazy)
        {
            Logger::println("lazy param");
            TypeFunction *ltf = new TypeFunction(NULL, arg->type, 0, LINKd);
            TypeDelegate *ltd = new TypeDelegate(ltf);
            argtype = ltd;
        }
        // byval
        else if (f->linkage != LINKintrinsic
                && gABI->passByVal(argtype))
        {
            if (!byref) a |= llvm::Attribute::ByVal;
            byref = true;
        }
        // sext/zext
        else if (!byref)
        {
            a |= DtoShouldExtend(argtype);
        }

        f->fty.args.push_back(new IrFuncTyArg(argtype, byref, a));
        lidx++;
    }

    if (f->linkage != LINKintrinsic) {
        // let the abi rewrite the types as necesary
        gABI->rewriteFunctionType(f);

        // Tell the ABI we're done with this function type
        gABI->doneWithFunctionType();
    }

    // build the function type
    std::vector<const LLType*> argtypes;
    argtypes.reserve(lidx);

    if (f->fty.arg_sret) argtypes.push_back(f->fty.arg_sret->ltype);
    if (f->fty.arg_this) argtypes.push_back(f->fty.arg_this->ltype);
    if (f->fty.arg_nest) argtypes.push_back(f->fty.arg_nest->ltype);
    if (f->fty.arg_arguments) argtypes.push_back(f->fty.arg_arguments->ltype);
    if (f->fty.arg_argptr) argtypes.push_back(f->fty.arg_argptr->ltype);

    size_t beg = argtypes.size();
    size_t nargs2 = f->fty.args.size();
    for (size_t i = 0; i < nargs2; i++)
    {
        argtypes.push_back(f->fty.args[i]->ltype);
    }

    // reverse params?
    if (f->fty.reverseParams && nargs2 > 1)
    {
        std::reverse(argtypes.begin() + beg, argtypes.end());
    }

    llvm::FunctionType* functype = llvm::FunctionType::get(f->fty.ret->ltype, argtypes, f->fty.c_vararg);
    f->ir.type = new llvm::PATypeHolder(functype);

    Logger::cout() << "Final function type: " << *functype << "\n";

    return functype;
}

//////////////////////////////////////////////////////////////////////////////////////////

static const llvm::FunctionType* DtoVaFunctionType(FuncDeclaration* fdecl)
{
    // type has already been resolved
    if (fdecl->type->ir.type != 0) {
        return llvm::cast<llvm::FunctionType>(fdecl->type->ir.type->get());
    }

    TypeFunction* f = (TypeFunction*)fdecl->type;
    const llvm::FunctionType* fty = 0;

    // create new ir funcTy
    f->fty.reset();
    f->fty.ret = new IrFuncTyArg(Type::tvoid, false);

    f->fty.args.push_back(new IrFuncTyArg(Type::tvoid->pointerTo(), false));

    if (fdecl->llvmInternal == LLVMva_start)
        fty = GET_INTRINSIC_DECL(vastart)->getFunctionType();
    else if (fdecl->llvmInternal == LLVMva_copy) {
        fty = GET_INTRINSIC_DECL(vacopy)->getFunctionType();
        f->fty.args.push_back(new IrFuncTyArg(Type::tvoid->pointerTo(), false));
    }
    else if (fdecl->llvmInternal == LLVMva_end)
        fty = GET_INTRINSIC_DECL(vaend)->getFunctionType();
    assert(fty);

    f->ir.type = new llvm::PATypeHolder(fty);
    return fty;
}

//////////////////////////////////////////////////////////////////////////////////////////

const llvm::FunctionType* DtoFunctionType(FuncDeclaration* fdecl)
{
    // handle for C vararg intrinsics
    if (fdecl->isVaIntrinsic())
        return DtoVaFunctionType(fdecl);

    // type has already been resolved
    if (fdecl->type->ir.type != 0)
        return llvm::cast<llvm::FunctionType>(fdecl->type->ir.type->get());

    Type *dthis=0, *dnest=0;

    if (fdecl->needThis()) {
        if (AggregateDeclaration* ad = fdecl->isMember2()) {
            Logger::println("isMember = this is: %s", ad->type->toChars());
            dthis = ad->type;
            const LLType* thisty = DtoType(dthis);
            //Logger::cout() << "this llvm type: " << *thisty << '\n';
            if (isaStruct(thisty) || (!gIR->structs.empty() && thisty == gIR->topstruct()->type->ir.type->get()))
                thisty = getPtrToType(thisty);
        }
        else {
            Logger::println("chars: %s type: %s kind: %s", fdecl->toChars(), fdecl->type->toChars(), fdecl->kind());
            assert(0);
        }
    }
    else if (fdecl->isNested()) {
        dnest = Type::tvoid->pointerTo();
    }

    const llvm::FunctionType* functype = DtoFunctionType(fdecl->type, dthis, dnest, fdecl->isMain());

    return functype;
}

//////////////////////////////////////////////////////////////////////////////////////////

static llvm::Function* DtoDeclareVaFunction(FuncDeclaration* fdecl)
{
    TypeFunction* f = (TypeFunction*)fdecl->type->toBasetype();
    const llvm::FunctionType* fty = DtoVaFunctionType(fdecl);
    llvm::Function* func = 0;

    if (fdecl->llvmInternal == LLVMva_start)
        func = GET_INTRINSIC_DECL(vastart);
    else if (fdecl->llvmInternal == LLVMva_copy)
        func = GET_INTRINSIC_DECL(vacopy);
    else if (fdecl->llvmInternal == LLVMva_end)
        func = GET_INTRINSIC_DECL(vaend);
    assert(func);

    fdecl->ir.irFunc->func = func;
    return func;
}

//////////////////////////////////////////////////////////////////////////////////////////

void DtoResolveFunction(FuncDeclaration* fdecl)
{
    if (!global.params.useUnitTests && fdecl->isUnitTestDeclaration()) {
        return; // ignore declaration completely
    }

    // is imported and we don't have access?
    if (fdecl->getModule() != gIR->dmodule)
    {
        if (fdecl->prot() == PROTprivate)
            return;
    }

    if (fdecl->ir.resolved) return;
    fdecl->ir.resolved = true;

    Logger::println("DtoResolveFunction(%s): %s", fdecl->toPrettyChars(), fdecl->loc.toChars());
    LOG_SCOPE;

    //printf("resolve function: %s\n", fdecl->toPrettyChars());

    if (fdecl->parent)
    if (TemplateInstance* tinst = fdecl->parent->isTemplateInstance())
    {
        TemplateDeclaration* tempdecl = tinst->tempdecl;
        if (tempdecl->llvmInternal == LLVMva_arg)
        {
            Logger::println("magic va_arg found");
            fdecl->llvmInternal = LLVMva_arg;
            fdecl->ir.declared = true;
            fdecl->ir.initialized = true;
            fdecl->ir.defined = true;
            return; // this gets mapped to an instruction so a declaration makes no sence
        }
        else if (tempdecl->llvmInternal == LLVMva_start)
        {
            Logger::println("magic va_start found");
            fdecl->llvmInternal = LLVMva_start;
        }
        else if (tempdecl->llvmInternal == LLVMintrinsic)
        {
            Logger::println("overloaded intrinsic found");
            fdecl->llvmInternal = LLVMintrinsic;
            DtoOverloadedIntrinsicName(tinst, tempdecl, fdecl->intrinsicName);
            fdecl->linkage = LINKintrinsic;
            ((TypeFunction*)fdecl->type)->linkage = LINKintrinsic;
        }
    }

    DtoFunctionType(fdecl);

    // queue declaration
    if (!fdecl->isAbstract())
        gIR->declareList.push_back(fdecl);
}

//////////////////////////////////////////////////////////////////////////////////////////

static void set_param_attrs(TypeFunction* f, llvm::Function* func, FuncDeclaration* fdecl)
{
    int funcNumArgs = func->getArgumentList().size();

    LLSmallVector<llvm::AttributeWithIndex, 9> attrs;
    llvm::AttributeWithIndex PAWI;

    int idx = 0;

    // handle implicit args
    #define ADD_PA(X) \
    if (f->fty.X) { \
        if (f->fty.X->attrs) { \
            PAWI.Index = idx; \
            PAWI.Attrs = f->fty.X->attrs; \
            attrs.push_back(PAWI); \
        } \
        idx++; \
    }

    ADD_PA(ret)
    ADD_PA(arg_sret)
    ADD_PA(arg_this)
    ADD_PA(arg_nest)
    ADD_PA(arg_arguments)
    ADD_PA(arg_argptr)

    #undef ADD_PA

    // set attrs on the rest of the arguments
    size_t n = Argument::dim(f->parameters);
    LLSmallVector<unsigned,8> attrptr(n, 0);

    for (size_t k = 0; k < n; ++k)
    {
        Argument* fnarg = Argument::getNth(f->parameters, k);
        assert(fnarg);

        attrptr[k] = f->fty.args[k]->attrs;
    }

    // reverse params?
    if (f->fty.reverseParams)
    {
        std::reverse(attrptr.begin(), attrptr.end());
    }

    // build rest of attrs list
    for (int i = 0; i < n; i++)
    {
        if (attrptr[i])
        {
            PAWI.Index = idx+i;
            PAWI.Attrs = attrptr[i];
            attrs.push_back(PAWI);
        }
    }

    llvm::AttrListPtr attrlist = llvm::AttrListPtr::get(attrs.begin(), attrs.end());
    func->setAttributes(attrlist);
}

//////////////////////////////////////////////////////////////////////////////////////////

void DtoDeclareFunction(FuncDeclaration* fdecl)
{
    if (fdecl->ir.declared) return;
    fdecl->ir.declared = true;

    Logger::println("DtoDeclareFunction(%s): %s", fdecl->toPrettyChars(), fdecl->loc.toChars());
    LOG_SCOPE;

    //printf("declare function: %s\n", fdecl->toPrettyChars());

    // intrinsic sanity check
    if (fdecl->llvmInternal == LLVMintrinsic && fdecl->fbody) {
        error(fdecl->loc, "intrinsics cannot have function bodies");
        fatal();
    }

    // get TypeFunction*
    Type* t = fdecl->type->toBasetype();
    TypeFunction* f = (TypeFunction*)t;

    bool declareOnly = !mustDefineSymbol(fdecl);

    if (fdecl->llvmInternal == LLVMva_start)
        declareOnly = true;

    if (!fdecl->ir.irFunc) {
        fdecl->ir.irFunc = new IrFunction(fdecl);
    }

    // mangled name
    const char* mangled_name;
    if (fdecl->llvmInternal == LLVMintrinsic)
        mangled_name = fdecl->intrinsicName.c_str();
    else
        mangled_name = fdecl->mangle();

    llvm::Function* vafunc = 0;
    if (fdecl->isVaIntrinsic())
        vafunc = DtoDeclareVaFunction(fdecl);

    // construct function
    const llvm::FunctionType* functype = DtoFunctionType(fdecl);
    llvm::Function* func = vafunc ? vafunc : gIR->module->getFunction(mangled_name);
    if (!func)
        func = llvm::Function::Create(functype, DtoLinkage(fdecl), mangled_name, gIR->module);

    // add func to IRFunc
    fdecl->ir.irFunc->func = func;

    // calling convention
    if (!vafunc && fdecl->llvmInternal != LLVMintrinsic)
        func->setCallingConv(DtoCallingConv(fdecl->loc, f->linkage));
    else // fall back to C, it should be the right thing to do
        func->setCallingConv(llvm::CallingConv::C);

    fdecl->ir.irFunc->func = func;
    assert(llvm::isa<llvm::FunctionType>(f->ir.type->get()));

    // parameter attributes
    if (!fdecl->isIntrinsic()) {
        set_param_attrs(f, func, fdecl);
    }

    // main
    if (fdecl->isMain()) {
        gIR->mainFunc = func;
    }

    // static ctor
    if (fdecl->isStaticCtorDeclaration()) {
        if (mustDefineSymbol(fdecl)) {
            gIR->ctors.push_back(fdecl);
        }
    }
    // static dtor
    else if (fdecl->isStaticDtorDeclaration()) {
        if (mustDefineSymbol(fdecl)) {
            gIR->dtors.push_back(fdecl);
        }
    }

    // we never reference parameters of function prototypes
    std::string str;
    if (!declareOnly)
    {
        // name parameters
        llvm::Function::arg_iterator iarg = func->arg_begin();

        if (f->fty.arg_sret) {
            iarg->setName(".sret_arg");
            fdecl->ir.irFunc->retArg = iarg;
            ++iarg;
        }

        if (f->fty.arg_this) {
            iarg->setName(".this_arg");
            fdecl->ir.irFunc->thisArg = iarg;
            assert(fdecl->ir.irFunc->thisArg);
            ++iarg;
        }
        else if (f->fty.arg_nest) {
            iarg->setName(".nest_arg");
            fdecl->ir.irFunc->nestArg = iarg;
            assert(fdecl->ir.irFunc->nestArg);
            ++iarg;
        }

        if (f->fty.arg_argptr) {
            iarg->setName("._arguments");
            fdecl->ir.irFunc->_arguments = iarg;
            ++iarg;
            iarg->setName("._argptr");
            fdecl->ir.irFunc->_argptr = iarg;
            ++iarg;
        }

        int k = 0;

        for (; iarg != func->arg_end(); ++iarg)
        {
            if (fdecl->parameters && fdecl->parameters->dim > k)
            {
                Dsymbol* argsym;
                if (f->fty.reverseParams)
                    argsym = (Dsymbol*)fdecl->parameters->data[fdecl->parameters->dim-k-1];
                else
                    argsym = (Dsymbol*)fdecl->parameters->data[k];

                VarDeclaration* argvd = argsym->isVarDeclaration();
                assert(argvd);
                assert(!argvd->ir.irLocal);
                argvd->ir.irLocal = new IrLocal(argvd);
                argvd->ir.irLocal->value = iarg;

                str = argvd->ident->toChars();
                str.append("_arg");
                iarg->setName(str);

                k++;
            }
            else
            {
                iarg->setName("unnamed");
            }
        }
    }

    if (fdecl->isUnitTestDeclaration() && !declareOnly)
        gIR->unitTests.push_back(fdecl);

    if (!declareOnly)
        gIR->defineList.push_back(fdecl);
    else
        assert(func->getLinkage() != llvm::GlobalValue::InternalLinkage);

    if (Logger::enabled())
        Logger::cout() << "func decl: " << *func << '\n';
}

//////////////////////////////////////////////////////////////////////////////////////////

// FIXME: this isn't too pretty!

void DtoDefineFunction(FuncDeclaration* fd)
{
    if (fd->ir.defined) return;
    fd->ir.defined = true;

    assert(fd->ir.declared);

    if (Logger::enabled())
        Logger::println("DtoDefineFunc(%s): %s", fd->toPrettyChars(), fd->loc.toChars());
    LOG_SCOPE;

    // if this function is naked, we take over right away! no standard processing!
    if (fd->naked)
    {
        DtoDefineNakedFunction(fd);
        return;
    }

    // debug info
    if (global.params.symdebug) {
        fd->ir.irFunc->diSubprogram = DtoDwarfSubProgram(fd);
    }

    Type* t = fd->type->toBasetype();
    TypeFunction* f = (TypeFunction*)t;
    assert(f->ir.type);

    llvm::Function* func = fd->ir.irFunc->func;
    const llvm::FunctionType* functype = func->getFunctionType();

    // sanity check
    assert(mustDefineSymbol(fd));

    // set module owner
    fd->ir.DModule = gIR->dmodule;

    // is there a body?
    if (fd->fbody == NULL)
        return;

    Logger::println("Doing function body for: %s", fd->toChars());
    assert(fd->ir.irFunc);
    IrFunction* irfunction = fd->ir.irFunc;
    gIR->functions.push_back(irfunction);

    if (fd->isMain())
        gIR->emitMain = true;

    std::string entryname("entry");

    llvm::BasicBlock* beginbb = llvm::BasicBlock::Create(entryname,func);
    llvm::BasicBlock* endbb = llvm::BasicBlock::Create("endentry",func);

    //assert(gIR->scopes.empty());
    gIR->scopes.push_back(IRScope(beginbb, endbb));

    // create alloca point
    llvm::Instruction* allocaPoint = new llvm::AllocaInst(LLType::Int32Ty, "alloca point", beginbb);
    irfunction->allocapoint = allocaPoint;

    // debug info - after all allocas, but before any llvm.dbg.declare etc
    if (global.params.symdebug) DtoDwarfFuncStart(fd);

    // need result variable?
    if (fd->vresult) {
        Logger::println("vresult value");
        fd->vresult->ir.irLocal = new IrLocal(fd->vresult);
        fd->vresult->ir.irLocal->value = DtoAlloca(DtoType(fd->vresult->type), "function_vresult");
    }
    
    // this hack makes sure the frame pointer elimination optimization is disabled.
    // this this eliminates a bunch of inline asm related issues.
    if (fd->inlineAsm)
    {
        // emit a call to llvm_eh_unwind_init
        LLFunction* hack = GET_INTRINSIC_DECL(eh_unwind_init);
        gIR->ir->CreateCall(hack, "");
    }

    // give the 'this' argument storage and debug info
    if (f->fty.arg_this)
    {
        LLValue* thisvar = irfunction->thisArg;
        assert(thisvar);

        LLValue* thismem = DtoAlloca(thisvar->getType(), "this");
        DtoStore(thisvar, thismem);
        irfunction->thisArg = thismem;
        
        assert(!fd->vthis->ir.irLocal);
        fd->vthis->ir.irLocal = new IrLocal(fd->vthis);
        fd->vthis->ir.irLocal->value = thismem;

        if (global.params.symdebug)
            DtoDwarfLocalVariable(thismem, fd->vthis);

    #if DMDV2
        if (fd->vthis->nestedrefs.dim)
    #else
        if (fd->vthis->nestedref)
    #endif
        {
            fd->nestedVars.insert(fd->vthis);
        }
    }

    // give arguments storage
    // and debug info
    if (fd->parameters)
    {
        size_t n = f->fty.args.size();
        assert(n == fd->parameters->dim);
        for (int i=0; i < n; ++i)
        {
            Dsymbol* argsym = (Dsymbol*)fd->parameters->data[i];
            VarDeclaration* vd = argsym->isVarDeclaration();
            assert(vd);

            IrLocal* irloc = vd->ir.irLocal;
            assert(irloc);

        #if DMDV2
            if (vd->nestedrefs.dim)
        #else
            if (vd->nestedref)
        #endif
            {
                fd->nestedVars.insert(vd);
            }

            bool refout = vd->storage_class & (STCref | STCout);
            bool lazy = vd->storage_class & STClazy;

            if (!refout && (!f->fty.args[i]->byref || lazy))
            {
                // alloca a stack slot for this first class value arg
                const LLType* argt;
                if (lazy)
                    argt = irloc->value->getType();
                else
                    argt = DtoType(vd->type);
                LLValue* mem = DtoAlloca(argt, vd->ident->toChars());

                // let the abi transform the argument back first
                DImValue arg_dval(vd->type, irloc->value);
                f->fty.getParam(vd->type, i, &arg_dval, mem);

                // set the arg var value to the alloca
                irloc->value = mem;
            }

            if (global.params.symdebug && !(isaArgument(irloc->value) && !isaArgument(irloc->value)->hasByValAttr()) && !refout)
                DtoDwarfLocalVariable(irloc->value, vd);
        }
    }

// need result variable? (nested)
#if DMDV2
    if (fd->vresult && fd->vresult->nestedrefs.dim) {
#else
    if (fd->vresult && fd->vresult->nestedref) {
#endif
        Logger::println("nested vresult value: %s", fd->vresult->toChars());
        fd->nestedVars.insert(fd->vresult);
    }

    // construct nested variables array
    if (!fd->nestedVars.empty())
    {
        Logger::println("has nested frame");
        // start with adding all enclosing parent frames until a static parent is reached
        int nparelems = 0;
        if (!fd->isStatic())
        {
            Dsymbol* par = fd->toParent2();
            while (par)
            {
                if (FuncDeclaration* parfd = par->isFuncDeclaration())
                {
                    nparelems += parfd->nestedVars.size();
                    // stop at first static
                    if (parfd->isStatic())
                        break;
                }
                else if (ClassDeclaration* parcd = par->isClassDeclaration())
                {
                    // nothing needed
                }
                else
                {
                    break;
                }

                par = par->toParent2();
            }
        }
        int nelems = fd->nestedVars.size() + nparelems;
        
        // make array type for nested vars
        const LLType* nestedVarsTy = LLArrayType::get(getVoidPtrType(), nelems);
    
        // alloca it
        LLValue* nestedVars = DtoAlloca(nestedVarsTy, ".nested_vars");
        
        // copy parent frame into beginning
        if (nparelems)
        {
            LLValue* src = irfunction->nestArg;
            if (!src)
            {
                assert(irfunction->thisArg);
                assert(fd->isMember2());
                LLValue* thisval = DtoLoad(irfunction->thisArg);
                ClassDeclaration* cd = fd->isMember2()->isClassDeclaration();
                assert(cd);
                assert(cd->vthis);
                src = DtoLoad(DtoGEPi(thisval, 0,cd->vthis->ir.irField->index, ".vthis"));
            }
            DtoMemCpy(nestedVars, src, DtoConstSize_t(nparelems*PTRSIZE));
        }
        
        // store in IrFunction
        irfunction->nestedVar = nestedVars;
        
        // go through all nested vars and assign indices
        int idx = nparelems;
        for (std::set<VarDeclaration*>::iterator i=fd->nestedVars.begin(); i!=fd->nestedVars.end(); ++i)
        {
            VarDeclaration* vd = *i;
            if (!vd->ir.irLocal)
                vd->ir.irLocal = new IrLocal(vd);

            if (vd->isParameter())
            {
                Logger::println("nested param: %s", vd->toChars());
                LLValue* gep = DtoGEPi(nestedVars, 0, idx);
                LLValue* val = DtoBitCast(vd->ir.irLocal->value, getVoidPtrType());
                DtoStore(val, gep);
            }
            else
            {
                Logger::println("nested var:   %s", vd->toChars());
            }

            vd->ir.irLocal->nestedIndex = idx++;
        }

        // fixup nested result variable
    #if DMDV2
        if (fd->vresult && fd->vresult->nestedrefs.dim) {
    #else
        if (fd->vresult && fd->vresult->nestedref) {
    #endif
            Logger::println("nested vresult value: %s", fd->vresult->toChars());
            LLValue* gep = DtoGEPi(nestedVars, 0, fd->vresult->ir.irLocal->nestedIndex);
            LLValue* val = DtoBitCast(fd->vresult->ir.irLocal->value, getVoidPtrType());
            DtoStore(val, gep);
        }
    }

    // copy _argptr and _arguments to a memory location
    if (f->linkage == LINKd && f->varargs == 1)
    {
        // _argptr
        LLValue* argptrmem = DtoAlloca(fd->ir.irFunc->_argptr->getType(), "_argptr_mem");
        new llvm::StoreInst(fd->ir.irFunc->_argptr, argptrmem, gIR->scopebb());
        fd->ir.irFunc->_argptr = argptrmem;

        // _arguments
        LLValue* argumentsmem = DtoAlloca(fd->ir.irFunc->_arguments->getType(), "_arguments_mem");
        new llvm::StoreInst(fd->ir.irFunc->_arguments, argumentsmem, gIR->scopebb());
        fd->ir.irFunc->_arguments = argumentsmem;
    }

    // output function body
    fd->fbody->toIR(gIR);

    // TODO: clean up this mess

//     std::cout << *func << std::endl;

    // llvm requires all basic blocks to end with a TerminatorInst but DMD does not put a return statement
    // in automatically, so we do it here.
    if (!gIR->scopereturned()) {
        // pass the previous block into this block
        if (global.params.symdebug) DtoDwarfFuncEnd(fd);
        if (func->getReturnType() == LLType::VoidTy) {
            llvm::ReturnInst::Create(gIR->scopebb());
        }
        else {
            if (!fd->isMain())
            {
                AsmBlockStatement* asmb = fd->fbody->endsWithAsm();
                if (asmb) {
                    assert(asmb->abiret);
                    llvm::ReturnInst::Create(asmb->abiret, gIR->scopebb());
                }
                else {
                    llvm::ReturnInst::Create(llvm::UndefValue::get(func->getReturnType()), gIR->scopebb());
                }
            }
            else
                llvm::ReturnInst::Create(llvm::Constant::getNullValue(func->getReturnType()), gIR->scopebb());
        }
    }

//     std::cout << *func << std::endl;

    // erase alloca point
    allocaPoint->eraseFromParent();
    allocaPoint = 0;
    gIR->func()->allocapoint = 0;

    gIR->scopes.pop_back();

    // get rid of the endentry block, it's never used
    assert(!func->getBasicBlockList().empty());
    func->getBasicBlockList().pop_back();

    gIR->functions.pop_back();

//     std::cout << *func << std::endl;
}

//////////////////////////////////////////////////////////////////////////////////////////

const llvm::FunctionType* DtoBaseFunctionType(FuncDeclaration* fdecl)
{
    Dsymbol* parent = fdecl->toParent();
    ClassDeclaration* cd = parent->isClassDeclaration();
    assert(cd);

    FuncDeclaration* f = fdecl;

    while (cd)
    {
        ClassDeclaration* base = cd->baseClass;
        if (!base)
            break;
        FuncDeclaration* f2 = base->findFunc(fdecl->ident, (TypeFunction*)fdecl->type);
        if (f2) {
            f = f2;
            cd = base;
        }
        else
            break;
    }

    DtoResolveDsymbol(f);
    return llvm::cast<llvm::FunctionType>(DtoType(f->type));
}

//////////////////////////////////////////////////////////////////////////////////////////

DValue* DtoArgument(Argument* fnarg, Expression* argexp)
{
    Logger::println("DtoArgument");
    LOG_SCOPE;

    DValue* arg = argexp->toElem(gIR);

    // ref/out arg
    if (fnarg && (fnarg->storageClass & (STCref | STCout)))
    {
        if (arg->isVar() || arg->isLRValue())
            arg = new DImValue(argexp->type, arg->getLVal());
        else
            arg = new DImValue(argexp->type, arg->getRVal());
    }
    // lazy arg
    else if (fnarg && (fnarg->storageClass & STClazy))
    {
        assert(argexp->type->toBasetype()->ty == Tdelegate);
        assert(!arg->isLVal());
        return arg;
    }
    // byval arg, but expr has no storage yet
    else if (DtoIsPassedByRef(argexp->type) && (arg->isSlice() || arg->isNull()))
    {
        LLValue* alloc = DtoAlloca(DtoType(argexp->type), ".tmp_arg");
        DVarValue* vv = new DVarValue(argexp->type, alloc);
        DtoAssign(argexp->loc, vv, arg);
        arg = vv;
    }

    return arg;
}

//////////////////////////////////////////////////////////////////////////////////////////

void DtoVariadicArgument(Expression* argexp, LLValue* dst)
{
    Logger::println("DtoVariadicArgument");
    LOG_SCOPE;
    DVarValue vv(argexp->type, dst);
    DtoAssign(argexp->loc, &vv, argexp->toElem(gIR));
}

//////////////////////////////////////////////////////////////////////////////////////////

bool FuncDeclaration::isIntrinsic()
{
    return (llvmInternal == LLVMintrinsic || isVaIntrinsic());
}

bool FuncDeclaration::isVaIntrinsic()
{
    return (llvmInternal == LLVMva_start ||
            llvmInternal == LLVMva_copy ||
            llvmInternal == LLVMva_end);
}