ldc/gen/nested.cpp

#include "gen/nested.h"

#include "gen/dvalue.h"
#include "gen/irstate.h"
#include "gen/llvmhelpers.h"
#include "gen/logger.h"
#include "gen/tollvm.h"

/****************************************************************************************/
/*////////////////////////////////////////////////////////////////////////////////////////
// NESTED VARIABLE HELPERS
////////////////////////////////////////////////////////////////////////////////////////*/

DValue* DtoNestedVariable(Loc loc, Type* astype, VarDeclaration* vd)
{
    Dsymbol* vdparent = vd->toParent2();
    assert(vdparent);
    
    IrFunction* irfunc = gIR->func();
    
    // is the nested variable in this scope?
    if (vdparent == irfunc->decl)
    {
        LLValue* val = vd->ir.getIrValue();
        return new DVarValue(astype, vd, val);
    }
    
    // get it from the nested context
    LLValue* ctx = 0;
    if (irfunc->decl->isMember2())
    {
        ClassDeclaration* cd = irfunc->decl->isMember2()->isClassDeclaration();
        LLValue* val = DtoLoad(irfunc->thisArg);
        ctx = DtoLoad(DtoGEPi(val, 0,cd->vthis->ir.irField->index, ".vthis"));
    }
    else
        ctx = irfunc->nestArg;
    assert(ctx);
    
    assert(vd->ir.irLocal);
    LLValue* val = DtoBitCast(ctx, getPtrToType(getVoidPtrType()));
    val = DtoGEPi1(val, vd->ir.irLocal->nestedIndex);
    val = DtoLoad(val);
    assert(vd->ir.irLocal->value);
    val = DtoBitCast(val, vd->ir.irLocal->value->getType(), vd->toChars());
    return new DVarValue(astype, vd, val);
}

void DtoNestedInit(VarDeclaration* vd)
{
    // alloca as usual if no value already
    if (!vd->ir.irLocal->value)
        vd->ir.irLocal->value = DtoAlloca(DtoType(vd->type), vd->toChars());
    
    // store the address into the nested vars array
    assert(vd->ir.irLocal->nestedIndex >= 0);
    LLValue* gep = DtoGEPi(gIR->func()->decl->ir.irFunc->nestedVar, 0, vd->ir.irLocal->nestedIndex);
    
    assert(isaPointer(vd->ir.irLocal->value));
    LLValue* val = DtoBitCast(vd->ir.irLocal->value, getVoidPtrType());
    
    DtoStore(val, gep);
}

LLValue* DtoNestedContext(Loc loc, Dsymbol* sym)
{
    Logger::println("DtoNestedContext for %s", sym->toPrettyChars());
    LOG_SCOPE;

    IrFunction* irfunc = gIR->func();

    // if this func has its own vars that are accessed by nested funcs
    // use its own context
    if (irfunc->nestedVar)
        return irfunc->nestedVar;
    // otherwise, it may have gotten a context from the caller
    else if (irfunc->nestArg)
        return irfunc->nestArg;
    // or just have a this argument
    else if (irfunc->thisArg)
    {
        ClassDeclaration* cd = irfunc->decl->isMember2()->isClassDeclaration();
        if (!cd || !cd->vthis)
            return getNullPtr(getVoidPtrType());
        LLValue* val = DtoLoad(irfunc->thisArg);
        return DtoLoad(DtoGEPi(val, 0,cd->vthis->ir.irField->index, ".vthis"));
    }
    else
    {
        return getNullPtr(getVoidPtrType());
    }
}

void DtoCreateNestedContext(FuncDeclaration* fd) {
    // 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");
        
        IrFunction* irfunction = fd->ir.irFunc;
        
        // 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);
        }
    }
}