Expression *scanVar(Dsymbol *s, InlineScanState *iss)
{
    //printf("scanVar(%s %s)\n", s->kind(), s->toPrettyChars());
    VarDeclaration *vd = s->isVarDeclaration();
    if (vd)
    {
        TupleDeclaration *td = vd->toAlias()->isTupleDeclaration();
        if (td)
        {
            for (size_t i = 0; i < td->objects->dim; i++)
            {
                DsymbolExp *se = (DsymbolExp *)(*td->objects)[i];
                assert(se->op == TOKdsymbol);
                scanVar(se->s, iss);    // TODO
            }
        }
        else if (vd->init)
        {
            if (ExpInitializer *ie = vd->init->isExpInitializer())
            {
                Expression *e = ie->exp->inlineScan(iss);
                if (vd->init != ie)     // DeclareExp with vd appears in e
                    return e;
                ie->exp = e;
            }
        }
    }
    else
    {
        s->inlineScan();
    }
    return NULL;
}

/***************************************
 * Return true if struct is POD (Plain Old Data).
 * This is defined as:
 *      not nested
 *      no postblits, constructors, destructors, or assignment operators
 *      no fields with with any of those
 * The idea being these are compatible with C structs.
 *
 * Note that D struct constructors can mean POD, since there is always default
 * construction with no ctor, but that interferes with OPstrpar which wants it
 * on the stack in memory, not in registers.
 */
bool StructDeclaration::isPOD()
{
    if (enclosing || cpctor || postblit || ctor || dtor)
        return false;

    /* Recursively check any fields have a constructor.
     * We should cache the results of this.
     */
    for (size_t i = 0; i < fields.dim; i++)
    {
        Dsymbol *s = fields[i];
        VarDeclaration *v = s->isVarDeclaration();
        assert(v && v->isField());
        if (v->storage_class & STCref)
            continue;
        Type *tv = v->type->toBasetype();
        while (tv->ty == Tsarray)
        {   TypeSArray *ta = (TypeSArray *)tv;
            tv = tv->nextOf()->toBasetype();
        }
        if (tv->ty == Tstruct)
        {   TypeStruct *ts = (TypeStruct *)tv;
            StructDeclaration *sd = ts->sym;
            if (!sd->isPOD())
                return false;
        }
    }
    return true;
}

        void visit(DeclarationExp *e)
        {
            VarDeclaration *v = e->declaration->isVarDeclaration();
            if (v)
            {
                result = v->checkNestedReference(sc, Loc());
                if (result)
                    return;

                /* Some expressions cause the frontend to create a temporary.
                 * For example, structs with cpctors replace the original
                 * expression e with:
                 *  __cpcttmp = __cpcttmp.cpctor(e);
                 *
                 * In this instance, we need to ensure that the original
                 * expression e does not have any nested references by
                 * checking the declaration initializer too.
                 */
                if (v->_init && v->_init->isExpInitializer())
                {
                    Expression *ie = initializerToExpression(v->_init);
                    result = lambdaCheckForNestedRef(ie, sc);
                }
            }
        }

        void visit(IndexExp *e)
        {
            if (e->e1->op == TOKvar)
            {
                VarDeclaration *v = ((VarExp *)e->e1)->var->isVarDeclaration();
                if (v && v->toParent2() == sc->func)
                {
                    Type *tb = v->type->toBasetype();
                    if (tb->ty == Tarray || tb->ty == Tsarray)
                    {
                        if (v->storage_class & STCvariadic)
                        {
                            error(e->loc, "escaping reference to the payload of variadic parameter %s", v);
                            return;
                        }
                    }
                }
            }

            Type *tb = e->e1->type->toBasetype();
            if (tb->ty == Tsarray)
            {
                e->e1->accept(this);
            }
        }

void VarExp::scanForNestedRef(Scope *sc)
{
    //printf("VarExp::scanForNestedRef(%s)\n", toChars());
    VarDeclaration *v = var->isVarDeclaration();
    if (v)
	v->checkNestedReference(sc, 0);
}

Expression *DeclarationExp::doInline(InlineDoState *ids)
{   DeclarationExp *de = (DeclarationExp *)copy();
    VarDeclaration *vd;

    //printf("DeclarationExp::doInline(%s)\n", toChars());
    vd = declaration->isVarDeclaration();
    if (vd)
    {
#if 0
        // Need to figure this out before inlining can work for tuples
        TupleDeclaration *td = vd->toAlias()->isTupleDeclaration();
        if (td)
        {
            for (size_t i = 0; i < td->objects->dim; i++)
            {   DsymbolExp *se = (DsymbolExp *)td->objects->data[i];
                assert(se->op == TOKdsymbol);
                se->s;
            }
            return st->objects->dim;
        }
#endif
        if (vd->isStatic() || vd->isConst())
            ;
        else
        {
            VarDeclaration *vto;

            vto = new VarDeclaration(vd->loc, vd->type, vd->ident, vd->init);
            *vto = *vd;
            vto->parent = ids->parent;
#if IN_DMD
            vto->csym = NULL;
            vto->isym = NULL;
#endif

            ids->from.push(vd);
            ids->to.push(vto);

            if (vd->init)
            {
                if (vd->init->isVoidInitializer())
                {
                    vto->init = new VoidInitializer(vd->init->loc);
                }
                else
                {
                    ExpInitializer *ie = vd->init->isExpInitializer();
                    assert(ie);
                    vto->init = new ExpInitializer(ie->loc, ie->exp->doInline(ids));
                }
            }
            de->declaration = (Dsymbol *) (void *)vto;
        }
    }
    /* This needs work, like DeclarationExp::toElem(), if we are
     * to handle TemplateMixin's. For now, we just don't inline them.
     */
    return de;
}

int DeclarationExp::inlineCost3(InlineCostState *ics)
{   int cost = 0;
    VarDeclaration *vd;

    //printf("DeclarationExp::inlineCost3()\n");
    vd = declaration->isVarDeclaration();
    if (vd)
    {
        TupleDeclaration *td = vd->toAlias()->isTupleDeclaration();
        if (td)
        {
#if 1
            return COST_MAX;    // finish DeclarationExp::doInline
#else
            for (size_t i = 0; i < td->objects->dim; i++)
            {   Object *o = (*td->objects)[i];
                if (o->dyncast() != DYNCAST_EXPRESSION)
                    return COST_MAX;
                Expression *eo = (Expression *)o;
                if (eo->op != TOKdsymbol)
                    return COST_MAX;
            }
            return td->objects->dim;
#endif
        }
        if (!ics->hdrscan && vd->isDataseg())
            return COST_MAX;
        cost += 1;

#if DMDV2
        if (vd->edtor)                  // if destructor required
            return COST_MAX;            // needs work to make this work
#endif
        // Scan initializer (vd->init)
        if (vd->init)
        {
            ExpInitializer *ie = vd->init->isExpInitializer();

            if (ie)
            {
                cost += expressionInlineCost(ie->exp, ics);
            }
        }
    }

    // These can contain functions, which when copied, get output twice.
    if (declaration->isStructDeclaration() ||
        declaration->isClassDeclaration() ||
        declaration->isFuncDeclaration() ||
        declaration->isTypedefDeclaration() ||
#if DMDV2
        declaration->isAttribDeclaration() ||
#endif
        declaration->isTemplateMixin())
        return COST_MAX;

    //printf("DeclarationExp::inlineCost3('%s')\n", toChars());
    return cost;
}

void StructDeclaration::toDt(dt_t **pdt)
{
    unsigned offset;
    unsigned i;
    dt_t *dt;

    //printf("StructDeclaration::toDt(), this='%s'\n", toChars());
    offset = 0;

    // Note equivalence of this loop to class's
    for (i = 0; i < fields.dim; i++)
    {
        VarDeclaration *v = (VarDeclaration *)fields.data[i];
        //printf("\tfield '%s' voffset %d, offset = %d\n", v->toChars(), v->offset, offset);
        dt = NULL;
        int sz;

        if (v->storage_class & STCref)
        {
            sz = PTRSIZE;
            if (v->offset >= offset)
                dtnzeros(&dt, sz);
        }
        else
        {
            sz = v->type->size();
            Initializer *init = v->init;
            if (init)
            {   //printf("\t\thas initializer %s\n", init->toChars());
                ExpInitializer *ei = init->isExpInitializer();
                Type *tb = v->type->toBasetype();
                if (ei && tb->ty == Tsarray)
                    ((TypeSArray *)tb)->toDtElem(&dt, ei->exp);
                else
                    dt = init->toDt();
            }
            else if (v->offset >= offset)
                v->type->toDt(&dt);
        }
        if (dt)
        {
            if (v->offset < offset)
                error("overlapping initialization for struct %s.%s", toChars(), v->toChars());
            else
            {
                if (offset < v->offset)
                    dtnzeros(pdt, v->offset - offset);
                dtcat(pdt, dt);
                offset = v->offset + sz;
            }
        }
    }

    if (offset < structsize)
        dtnzeros(pdt, structsize - offset);

    dt_optimize(*pdt);
}

int DeclarationExp::inlineCost(InlineCostState *ics)
{   int cost = 0;
    VarDeclaration *vd;

    //printf("DeclarationExp::inlineCost()\n");
    vd = declaration->isVarDeclaration();
    if (vd)
    {
        TupleDeclaration *td = vd->toAlias()->isTupleDeclaration();
        if (td)
        {
#if 1
            return COST_MAX;    // finish DeclarationExp::doInline
#else
            for (size_t i = 0; i < td->objects->dim; i++)
            {   Object *o = (*td->objects)[i];
                if (o->dyncast() != DYNCAST_EXPRESSION)
                    return COST_MAX;
                Expression *eo = (Expression *)o;
                if (eo->op != TOKdsymbol)
                    return COST_MAX;
            }
            return td->objects->dim;
#endif
        }
        // This breaks on LDC too, since nested static variables have internal
        // linkage and thus can't be referenced from other objects.
        if (!ics->hdrscan && vd->isDataseg())
            return COST_MAX;
        cost += 1;

        // Scan initializer (vd->init)
        if (vd->init)
        {
            ExpInitializer *ie = vd->init->isExpInitializer();

            if (ie)
            {
                cost += ie->exp->inlineCost(ics);
            }
        }
    }

    // These can contain functions, which when copied, get output twice.
    // These break on LDC too, since nested static variables and functions have
    // internal linkage and thus can't be referenced from other objects.
    if (declaration->isStructDeclaration() ||
            declaration->isClassDeclaration() ||
            declaration->isFuncDeclaration() ||
            declaration->isTypedefDeclaration() ||
            declaration->isTemplateMixin())
        return COST_MAX;

    //printf("DeclarationExp::inlineCost('%s')\n", toChars());
    return cost;
}

        void check(Loc loc, Declaration *d)
        {
            assert(d);
            VarDeclaration *v = d->isVarDeclaration();
            if (v && v->toParent2() == sc->func)
            {
                if (v->isDataseg())
                    return;
                if ((v->storage_class & (STCref | STCout)) == 0)
                {
                    error(loc, "escaping reference to local variable %s", v);
                    return;
                }

                if (global.params.useDIP25 &&
                        (v->storage_class & (STCref | STCout)) && !(v->storage_class & (STCreturn | STCforeach)))
                {
                    if (sc->func->flags & FUNCFLAGreturnInprocess)
                    {
                        //printf("inferring 'return' for variable '%s'\n", v->toChars());
                        v->storage_class |= STCreturn;
                        if (v == sc->func->vthis)
                        {
                            TypeFunction *tf = (TypeFunction *)sc->func->type;
                            if (tf->ty == Tfunction)
                            {
                                //printf("'this' too\n");
                                tf->isreturn = true;
                            }
                        }
                    }
                    else if (sc->module && sc->module->isRoot())
                    {
                        //printf("escaping reference to local ref variable %s\n", v->toChars());
                        //printf("storage class = x%llx\n", v->storage_class);
                        error(loc, "escaping reference to local ref variable %s", v);
                    }
                    return;
                }

                if (v->storage_class & STCref &&
                        v->storage_class & (STCforeach | STCtemp) &&
                        v->init)
                {
                    // (ref v = ex; ex)
                    if (ExpInitializer *ez = v->init->isExpInitializer())
                    {
                        assert(ez->exp && ez->exp->op == TOKconstruct);
                        Expression *ex = ((ConstructExp *)ez->exp)->e2;
                        ex->accept(this);
                        return;
                    }
                }
            }
        }

/***************************************
 * Fit elements[] to the corresponding type of field[].
 * Input:
 *      loc
 *      sc
 *      elements    The explicit arguments that given to construct object.
 *      stype       The constructed object type.
 * Returns false if any errors occur.
 * Otherwise, returns true and elements[] are rewritten for the output.
 */
bool StructDeclaration::fit(Loc loc, Scope *sc, Expressions *elements, Type *stype)
{
    if (!elements)
        return true;

    size_t nfields = fields.dim - isNested();
    size_t offset = 0;
    for (size_t i = 0; i < elements->dim; i++)
    {
        Expression *e = (*elements)[i];
        if (!e)
            continue;

        e = resolveProperties(sc, e);
        if (i >= nfields)
        {
            if (i == fields.dim - 1 && isNested() && e->op == TOKnull)
            {
                // CTFE sometimes creates null as hidden pointer; we'll allow this.
                continue;
            }
            ::error(loc, "more initializers than fields (%d) of %s", nfields, toChars());
            return false;
        }
        VarDeclaration *v = fields[i];
        if (v->offset < offset)
        {
            ::error(loc, "overlapping initialization for %s", v->toChars());
            return false;
        }
        offset = (unsigned)(v->offset + v->type->size());

        Type *telem = v->type;
        if (stype)
            telem = telem->addMod(stype->mod);
        Type *origType = telem;
        while (!e->implicitConvTo(telem) && telem->toBasetype()->ty == Tsarray)
        {
            /* Static array initialization, as in:
             *  T[3][5] = e;
             */
            telem = telem->toBasetype()->nextOf();
        }

        if (!e->implicitConvTo(telem))
            telem = origType;  // restore type for better diagnostic

        e = e->implicitCastTo(sc, telem);
        if (e->op == TOKerror)
            return false;

        (*elements)[i] = e->isLvalue() ? callCpCtor(sc, e) : valueNoDtor(e);
    }
    return true;
}

void scanVar(Dsymbol *s, InlineScanState *iss)
{
    VarDeclaration *vd = s->isVarDeclaration();
    if (vd)
    {
        TupleDeclaration *td = vd->toAlias()->isTupleDeclaration();
        if (td)
        {
            for (size_t i = 0; i < td->objects->dim; i++)
            {   DsymbolExp *se = (DsymbolExp *)td->objects->tdata()[i];
                assert(se->op == TOKdsymbol);
                scanVar(se->s, iss);
            }
        }
        else
        {
            // Scan initializer (vd->init)
            if (vd->init)
            {
                ExpInitializer *ie = vd->init->isExpInitializer();

                if (ie)
                {
#if DMDV2
                    if (vd->type)
                    {   Type *tb = vd->type->toBasetype();
                        if (tb->ty == Tstruct)
                        {   StructDeclaration *sd = ((TypeStruct *)tb)->sym;
                            if (sd->cpctor)
                            {   /* The problem here is that if the initializer is a
                                 * function call that returns a struct S with a cpctor:
                                 *   S s = foo();
                                 * the postblit is done by the return statement in foo()
                                 * in s2ir.c, the intermediate code generator.
                                 * But, if foo() is inlined and now the code looks like:
                                 *   S s = x;
                                 * the postblit is not there, because such assignments
                                 * are rewritten as s.cpctor(&x) by the front end.
                                 * So, the inlining won't get the postblit called.
                                 * Work around by not inlining these cases.
                                 * A proper fix would be to move all the postblit
                                 * additions to the front end.
                                 */
                                return;
                            }
                        }
                    }
#endif
                    ie->exp = ie->exp->inlineScan(iss);
                }
            }
        }
    }
}

int StructDeclaration::needOpEquals()
{
#define X 0
    if (X) printf("StructDeclaration::needOpEquals() %s\n", toChars());

    if (hasIdentityEquals)
        goto Lneed;

#if 0
    if (isUnionDeclaration())
        goto Ldontneed;
#endif

    /* If any of the fields has an opEquals, then we
     * need it too.
     */
    for (size_t i = 0; i < fields.dim; i++)
    {
        Dsymbol *s = fields[i];
        VarDeclaration *v = s->isVarDeclaration();
        assert(v && v->isField());
        if (v->storage_class & STCref)
            continue;
        Type *tv = v->type->toBasetype();
#if 0
        if (tv->isfloating())
            goto Lneed;
        if (tv->ty == Tarray)
            goto Lneed;
        if (tv->ty == Tclass)
            goto Lneed;
#endif
        while (tv->ty == Tsarray)
        {   TypeSArray *ta = (TypeSArray *)tv;
            tv = tv->nextOf()->toBasetype();
        }
        if (tv->ty == Tstruct)
        {   TypeStruct *ts = (TypeStruct *)tv;
            StructDeclaration *sd = ts->sym;
            if (sd->needOpEquals())
                goto Lneed;
        }
    }
Ldontneed:
    if (X) printf("\tdontneed\n");
    return 0;

Lneed:
    if (X) printf("\tneed\n");
    return 1;
#undef X
}

    void visit(DeclarationExp *e)
    {
        //printf("DeclarationExp::inlineCost3()\n");
        VarDeclaration *vd = e->declaration->isVarDeclaration();
        if (vd)
        {
            TupleDeclaration *td = vd->toAlias()->isTupleDeclaration();
            if (td)
            {
                cost = COST_MAX;    // finish DeclarationExp::doInline
                return;
            }
            if (!hdrscan && vd->isDataseg())
            {
                cost = COST_MAX;
                return;
            }

            if (vd->edtor)
            {
                // if destructor required
                // needs work to make this work
                cost = COST_MAX;
                return;
            }
            // Scan initializer (vd->init)
            if (vd->_init)
            {
                ExpInitializer *ie = vd->_init->isExpInitializer();

                if (ie)
                {
                    expressionInlineCost(ie->exp);
                }
            }
            cost += 1;
        }

        // These can contain functions, which when copied, get output twice.
        if (e->declaration->isStructDeclaration() ||
            e->declaration->isClassDeclaration() ||
            e->declaration->isFuncDeclaration() ||
            e->declaration->isAttribDeclaration() ||
            e->declaration->isTemplateMixin())
        {
            cost = COST_MAX;
            return;
        }

        //printf("DeclarationExp::inlineCost3('%s')\n", toChars());
    }

 /* Returns:
  *  0       this member doesn't need further processing to determine struct size
  *  1       this member does
  */
 static int func(Dsymbol *s, void *param)
 {   SV *psv = (SV *)param;
     VarDeclaration *v = s->isVarDeclaration();
     if (v)
     {
         if (v->scope)
             v->semantic(NULL);
         if (v->storage_class & (STCstatic | STCextern | STCtls | STCgshared | STCmanifest | STCctfe | STCtemplateparameter))
             return 0;
         if (v->isField() && v->sem >= SemanticDone)
             return 0;
         return 1;
     }
     return 0;
 }

Expression *fromConstInitializer(Expression *e1)
{
    //printf("fromConstInitializer(%s)\n", e1->toChars());
    if (e1->op == TOKvar)
    {   VarExp *ve = (VarExp *)e1;
        VarDeclaration *v = ve->var->isVarDeclaration();
        if (v && !v->originalType && v->scope)  // semantic() not yet run
            v->semantic (v->scope);
        if (v && v->isConst() && v->init)
        {   Expression *ei = v->init->toExpression();
            if (ei && ei->type)
                e1 = ei;
        }
    }
    return e1;
}

void ldc::DIBuilder::AddBaseFields(ClassDeclaration *sd, llvm::DIFile file,
                                     std::vector<llvm::Value*> &elems)
{
    if (sd->baseClass)
    {
        AddBaseFields(sd->baseClass, file, elems);
    }

    ArrayIter<VarDeclaration> it(sd->fields);
    size_t narr = sd->fields.dim;
    elems.reserve(narr);
    for (; !it.done(); it.next())
    {
        VarDeclaration* vd = it.get();
        elems.push_back(CreateMemberType(vd->loc.linnum, vd->type, file, vd->toChars(), vd->offset));
    }
}

  void visit(ExpStatement *stmt) override {
    IF_LOG Logger::println("ExpStatement::toNakedIR(): %s",
                           stmt->loc.toChars());
    LOG_SCOPE;

    // This happens only if there is a ; at the end:
    // asm { naked; ... };
    // Is this a legal AST?
    if (!stmt->exp) {
      return;
    }

    // only expstmt supported in declarations
    if (!stmt->exp || stmt->exp->op != TOKdeclaration) {
      visit(static_cast<Statement *>(stmt));
      return;
    }

    DeclarationExp *d = static_cast<DeclarationExp *>(stmt->exp);
    VarDeclaration *vd = d->declaration->isVarDeclaration();
    FuncDeclaration *fd = d->declaration->isFuncDeclaration();
    EnumDeclaration *ed = d->declaration->isEnumDeclaration();

    // and only static variable/function declaration
    // no locals or nested stuffies!
    if (!vd && !fd && !ed) {
      visit(static_cast<Statement *>(stmt));
      return;
    }
    if (vd && !(vd->storage_class & (STCstatic | STCmanifest))) {
      error(vd->loc, "non-static variable `%s` not allowed in naked function",
            vd->toChars());
      return;
    }
    if (fd && !fd->isStatic()) {
      error(fd->loc,
            "non-static nested function `%s` not allowed in naked function",
            fd->toChars());
      return;
    }
    // enum decls should always be safe

    // make sure the symbols gets processed
    // TODO: codegen() here is likely incorrect
    Declaration_codegen(d->declaration, irs);
  }

 void visit(DeclarationExp *e)
 {
     // Note that, walkPostorder does not support DeclarationExp today.
     VarDeclaration *v = e->declaration->isVarDeclaration();
     if (v && !(v->storage_class & STCmanifest) && !v->isDataseg() && v->init)
     {
         if (v->init->isVoidInitializer())
         {
         }
         else
         {
             ExpInitializer *ei = v->init->isExpInitializer();
             assert(ei);
             doCond(ei->exp);
         }
     }
 }

int StructDeclaration::needOpAssign()
{
#define X 0
    if (X) printf("StructDeclaration::needOpAssign() %s\n", toChars());

    if (hasIdentityAssign)
        goto Lneed;         // because has identity==elaborate opAssign

    if (dtor || postblit)
        goto Lneed;

    /* If any of the fields need an opAssign, then we
     * need it too.
     */
    for (size_t i = 0; i < fields.dim; i++)
    {
        Dsymbol *s = fields[i];
        VarDeclaration *v = s->isVarDeclaration();
        assert(v && v->isField());
        if (v->storage_class & STCref)
            continue;
        Type *tv = v->type->toBasetype();
        while (tv->ty == Tsarray)
        {   TypeSArray *ta = (TypeSArray *)tv;
            tv = tv->nextOf()->toBasetype();
        }
        if (tv->ty == Tstruct)
        {   TypeStruct *ts = (TypeStruct *)tv;
            StructDeclaration *sd = ts->sym;
            if (sd->needOpAssign())
                goto Lneed;
        }
    }
Ldontneed:
    if (X) printf("\tdontneed\n");
    return 0;

Lneed:
    if (X) printf("\tneed\n");
    return 1;
#undef X
}