C++ VarDeclaration::isParameter方法代码示例

//.........这里部分代码省略.........
            {
                // reference parameters are just pointers
                memsize = Target::ptrsize;
                memalignsize = memsize;
                xalign = STRUCTALIGN_DEFAULT;
            }
            else
            {
                memsize = v->type->size();
                memalignsize = v->type->alignsize();
                xalign = v->alignment;
            }
            AggregateDeclaration::alignmember(xalign, memalignsize, &offset);
            v->offset = offset;
            offset += memsize;

            /* Set Sscope to closure */
            Symbol *vsym = toSymbol(v);
            assert(vsym->Sscope == NULL);
            vsym->Sscope = sclosure;

            /* Add variable as closure type member */
            symbol_struct_addField(Closstru->Ttag, vsym->Sident, vsym->Stype, v->offset);
            //printf("closure field %s: memalignsize: %i, offset: %i\n", vsym->Sident, memalignsize, v->offset);

            /* Can't do nrvo if the variable is put in a closure, since
             * what the shidden points to may no longer exist.
             */
            if (fd->nrvo_can && fd->nrvo_var == v)
            {
                fd->nrvo_can = 0;
            }
        }
        // offset is now the size of the closure
        Closstru->Ttag->Sstruct->Sstructsize = offset;

        // Allocate memory for the closure
        elem *e = el_long(TYsize_t, offset);
        e = el_bin(OPcall, TYnptr, el_var(getRtlsym(RTLSYM_ALLOCMEMORY)), e);
        toTraceGC(irs, e, &fd->loc);

        // Assign block of memory to sclosure
        //    sclosure = allocmemory(sz);
        e = el_bin(OPeq, TYvoid, el_var(sclosure), e);

        // Set the first element to sthis
        //    *(sclosure + 0) = sthis;
        elem *ethis;
        if (irs->sthis)
            ethis = el_var(irs->sthis);
        else
            ethis = el_long(TYnptr, 0);
        elem *ex = el_una(OPind, TYnptr, el_var(sclosure));
        ex = el_bin(OPeq, TYnptr, ex, ethis);
        e = el_combine(e, ex);

        // Copy function parameters into closure
        for (size_t i = 0; i < fd->closureVars.dim; i++)
        {
            VarDeclaration *v = fd->closureVars[i];

            if (!v->isParameter())
                continue;
            tym_t tym = totym(v->type);
            bool win64ref = ISWIN64REF(v);
            if (win64ref)
            {
                if (v->storage_class & STClazy)
                    tym = TYdelegate;
            }
            else if (ISREF(v, NULL))
                tym = TYnptr;   // reference parameters are just pointers
            else if (v->storage_class & STClazy)
                tym = TYdelegate;
            ex = el_bin(OPadd, TYnptr, el_var(sclosure), el_long(TYsize_t, v->offset));
            ex = el_una(OPind, tym, ex);
            elem *ev = el_var(toSymbol(v));
            if (win64ref)
            {
                ev->Ety = TYnptr;
                ev = el_una(OPind, tym, ev);
                if (tybasic(ev->Ety) == TYstruct || tybasic(ev->Ety) == TYarray)
                    ev->ET = Type_toCtype(v->type);
            }
            if (tybasic(ex->Ety) == TYstruct || tybasic(ex->Ety) == TYarray)
            {
                ::type *t = Type_toCtype(v->type);
                ex->ET = t;
                ex = el_bin(OPstreq, tym, ex, ev);
                ex->ET = t;
            }
            else
                ex = el_bin(OPeq, tym, ex, ev);

            e = el_combine(e, ex);
        }

        block_appendexp(irs->blx->curblock, e);
    }
}

//.........这里部分代码省略.........
                v->error("cannot reference variadic arguments from closure");
#endif
            /* Align and allocate space for v in the closure
             * just like AggregateDeclaration::addField() does.
             */
            unsigned memsize;
            unsigned memalignsize;
            structalign_t xalign;
#if DMDV2
            if (v->storage_class & STClazy)
            {
                /* Lazy variables are really delegates,
                 * so give same answers that TypeDelegate would
                 */
                memsize = PTRSIZE * 2;
                memalignsize = memsize;
                xalign = global.structalign;
            }
            else if (v->isRef() || v->isOut())
            {    // reference parameters are just pointers
                memsize = PTRSIZE;
                memalignsize = memsize;
                xalign = global.structalign;
            }
            else
#endif
            {
                memsize = v->type->size();
                memalignsize = v->type->alignsize();
                xalign = v->alignment;
            }
            AggregateDeclaration::alignmember(xalign, memalignsize, &offset);
            v->offset = offset;
            offset += memsize;

            /* Can't do nrvo if the variable is put in a closure, since
             * what the shidden points to may no longer exist.
             */
            if (nrvo_can && nrvo_var == v)
            {
                nrvo_can = 0;
            }
        }
        // offset is now the size of the closure

        // Allocate memory for the closure
        elem *e;
        e = el_long(TYsize_t, offset);
        e = el_bin(OPcall, TYnptr, el_var(rtlsym[RTLSYM_ALLOCMEMORY]), e);

        // Assign block of memory to sclosure
        //    sclosure = allocmemory(sz);
        e = el_bin(OPeq, TYvoid, el_var(sclosure), e);

        // Set the first element to sthis
        //    *(sclosure + 0) = sthis;
        elem *ethis;
        if (irs->sthis)
            ethis = el_var(irs->sthis);
        else
            ethis = el_long(TYnptr, 0);
        elem *ex = el_una(OPind, TYnptr, el_var(sclosure));
        ex = el_bin(OPeq, TYnptr, ex, ethis);
        e = el_combine(e, ex);

        // Copy function parameters into closure
        for (size_t i = 0; i < closureVars.dim; i++)
        {   VarDeclaration *v = closureVars[i];

            if (!v->isParameter())
                continue;
            tym_t tym = v->type->totym();
            if (
#if !SARRAYVALUE
                v->type->toBasetype()->ty == Tsarray ||
#endif
                v->isOut() || v->isRef())
                tym = TYnptr;   // reference parameters are just pointers
#if DMDV2
            else if (v->storage_class & STClazy)
                tym = TYdelegate;
#endif
            ex = el_bin(OPadd, TYnptr, el_var(sclosure), el_long(TYsize_t, v->offset));
            ex = el_una(OPind, tym, ex);
            if (tybasic(ex->Ety) == TYstruct || tybasic(ex->Ety) == TYarray)
            {
                ::type *t = v->type->toCtype();
                ex->ET = t;
                ex = el_bin(OPstreq, tym, ex, el_var(v->toSymbol()));
                ex->ET = t;
            }
            else
                ex = el_bin(OPeq, tym, ex, el_var(v->toSymbol()));

            e = el_combine(e, ex);
        }

        block_appendexp(irs->blx->curblock, e);
    }
}

static bool checkReturnEscapeImpl(Scope *sc, Expression *e, bool refs, bool gag)
{
    //printf("[%s] checkReturnEscapeImpl, e = %s\n", e->loc->toChars(), e->toChars());
    EscapeByResults er;

    if (refs)
        escapeByRef(e, &er);
    else
        escapeByValue(e, &er);

    if (!er.byref.dim && !er.byvalue.dim && !er.byexp.dim)
        return false;

    bool result = false;
    for (size_t i = 0; i < er.byvalue.dim; i++)
    {
        VarDeclaration *v = er.byvalue[i];
        //printf("byvalue %s\n", v->toChars());
        if (v->isDataseg())
            continue;

        Dsymbol *p = v->toParent2();

        if ((v->isScope() || (v->storage_class & STCmaybescope)) &&
            !(v->storage_class & STCreturn) &&
            v->isParameter() &&
            sc->func->flags & FUNCFLAGreturnInprocess &&
            p == sc->func)
        {
            inferReturn(sc->func, v);        // infer addition of 'return'
            continue;
        }

        if (v->isScope())
        {
            if (v->storage_class & STCreturn)
                continue;

            if (sc->_module && sc->_module->isRoot() &&
                /* This case comes up when the ReturnStatement of a __foreachbody is
                 * checked for escapes by the caller of __foreachbody. Skip it.
                 *
                 * struct S { static int opApply(int delegate(S*) dg); }
                 * S* foo() {
                 *    foreach (S* s; S) // create __foreachbody for body of foreach
                 *        return s;     // s is inferred as 'scope' but incorrectly tested in foo()
                 *    return null; }
                 */
                !(!refs && p->parent == sc->func))
            {
                // Only look for errors if in module listed on command line
                if (global.params.vsafe) // https://issues.dlang.org/show_bug.cgi?id=17029
                {
                    if (!gag)
                        error(e->loc, "scope variable %s may not be returned", v->toChars());
                    result = true;
                }
                continue;
            }
        }
        else if (v->storage_class & STCvariadic && p == sc->func)
        {
            Type *tb = v->type->toBasetype();
            if (tb->ty == Tarray || tb->ty == Tsarray)
            {
                if (!gag)
                    error(e->loc, "returning `%s` escapes a reference to variadic parameter `%s`", e->toChars(), v->toChars());
                result = false;
            }
        }
        else
        {
            //printf("no infer for %s\n", v->toChars());
            v->doNotInferScope = true;
        }
    }

    for (size_t i = 0; i < er.byref.dim; i++)
    {
        VarDeclaration *v = er.byref[i];
        //printf("byref %s\n", v->toChars());
        if (v->isDataseg())
            continue;

        Dsymbol *p = v->toParent2();

        if ((v->storage_class & (STCref | STCout)) == 0)
        {
            if (p == sc->func)
            {
                escapingRef(v, e, result, gag);
                continue;
            }
            FuncDeclaration *fd = p->isFuncDeclaration();
            if (fd && sc->func->flags & FUNCFLAGreturnInprocess)
            {
                /* Code like:
                 *   int x;
                 *   auto dg = () { return &x; }
                 * Making it:
//.........这里部分代码省略.........

void DtoCreateNestedContext(FuncDeclaration* fd) {
    Logger::println("DtoCreateNestedContext for %s", fd->toChars());
    LOG_SCOPE

    DtoCreateNestedContextType(fd);

    // construct nested variables array
    if (!fd->nestedVars.empty())
    {
        IrFunction* irfunction = fd->ir.irFunc;
        unsigned depth = irfunction->depth;
        LLStructType *frameType = irfunction->frameType;
        // Create frame for current function and append to frames list
        // FIXME: alignment ?
        LLValue* frame = 0;
        if (fd->needsClosure())
            frame = DtoGcMalloc(frameType, ".frame");
        else
            frame = DtoRawAlloca(frameType, 0, ".frame");

        // copy parent frames into beginning
        if (depth != 0) {
            LLValue* src = irfunction->nestArg;
            if (!src) {
                assert(irfunction->thisArg);
                assert(fd->isMember2());
                LLValue* thisval = DtoLoad(irfunction->thisArg);
                AggregateDeclaration* cd = fd->isMember2();
                assert(cd);
                assert(cd->vthis);
                Logger::println("Indexing to 'this'");
                if (cd->isStructDeclaration())
                    src = DtoExtractValue(thisval, cd->vthis->ir.irField->index, ".vthis");
                else
                    src = DtoLoad(DtoGEPi(thisval, 0, cd->vthis->ir.irField->index, ".vthis"));
            } else {
                src = DtoLoad(src);
            }
            if (depth > 1) {
                src = DtoBitCast(src, getVoidPtrType());
                LLValue* dst = DtoBitCast(frame, getVoidPtrType());
                DtoMemCpy(dst, src, DtoConstSize_t((depth-1) * PTRSIZE),
                    getABITypeAlign(getVoidPtrType()));
            }
            // Copy nestArg into framelist; the outer frame is not in the list of pointers
            src = DtoBitCast(src, frameType->getContainedType(depth-1));
            LLValue* gep = DtoGEPi(frame, 0, depth-1);
            DtoAlignedStore(src, gep);
        }

        // store context in IrFunction
        irfunction->nestedVar = frame;

        // go through all nested vars and assign addresses where possible.
        for (std::set<VarDeclaration*>::iterator i=fd->nestedVars.begin(); i!=fd->nestedVars.end(); ++i)
        {
            VarDeclaration* vd = *i;

            LLValue* gep = DtoGEPi(frame, 0, vd->ir.irLocal->nestedIndex, vd->toChars());
            if (vd->isParameter()) {
                Logger::println("nested param: %s", vd->toChars());
                LOG_SCOPE
                IrParameter* parm = vd->ir.irParam;

                if (parm->arg->byref)
                {
                    storeVariable(vd, gep);
                }
                else
                {
                    Logger::println("Copying to nested frame");
                    // The parameter value is an alloca'd stack slot.
                    // Copy to the nesting frame and leave the alloca for
                    // the optimizers to clean up.
                    DtoStore(DtoLoad(parm->value), gep);
                    gep->takeName(parm->value);
                    parm->value = gep;
                }
            } else {
                Logger::println("nested var:   %s", vd->toChars());
                assert(!vd->ir.irLocal->value);
                vd->ir.irLocal->value = gep;
            }

            if (global.params.symdebug) {
                LLSmallVector<LLValue*, 2> addr;
                dwarfOpOffset(addr, frameType, vd->ir.irLocal->nestedIndex);
                DtoDwarfLocalVariable(frame, vd, addr);
            }
        }
    }
}

static void DtoCreateNestedContextType(FuncDeclaration* fd) {
    Logger::println("DtoCreateNestedContextType for %s", fd->toChars());
    LOG_SCOPE

    DtoDeclareFunction(fd);

    if (fd->ir.irFunc->nestedContextCreated)
        return;
    fd->ir.irFunc->nestedContextCreated = true;

    if (fd->nestedVars.empty()) {
        // fill nestedVars
        size_t nnest = fd->closureVars.dim;
        for (size_t i = 0; i < nnest; ++i)
        {
            VarDeclaration* vd = static_cast<VarDeclaration*>(fd->closureVars.data[i]);
            fd->nestedVars.insert(vd);
        }
    }

    // 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

        LLStructType* innerFrameType = NULL;
        unsigned depth = -1;
        if (!fd->isStatic()) {
            if (FuncDeclaration* parfd = getParentFunc(fd, true)) {
                // Make sure the parent has already been analyzed.
                DtoCreateNestedContextType(parfd);

                innerFrameType = parfd->ir.irFunc->frameType;
                if (innerFrameType)
                    depth = parfd->ir.irFunc->depth;
            }
        }
        fd->ir.irFunc->depth = ++depth;

        Logger::cout() << "Function " << fd->toChars() << " has depth " << depth << '\n';

        typedef std::vector<LLType*> TypeVec;
        TypeVec types;
        if (depth != 0) {
            assert(innerFrameType);
            // Add frame pointer types for all but last frame
            if (depth > 1) {
                for (unsigned i = 0; i < (depth - 1); ++i) {
                    types.push_back(innerFrameType->getElementType(i));
                }
            }
            // Add frame pointer type for last frame
            types.push_back(LLPointerType::getUnqual(innerFrameType));
        }

        if (Logger::enabled() && depth != 0) {
            Logger::println("Frame types: ");
            LOG_SCOPE;
            for (TypeVec::iterator i = types.begin(); i != types.end(); ++i)
                Logger::cout() << **i << '\n';
        }

        // Add the direct nested variables of this function, and update their indices to match.
        // TODO: optimize ordering for minimal space usage?
        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);

            vd->ir.irLocal->nestedIndex = types.size();
            vd->ir.irLocal->nestedDepth = depth;
            if (vd->isParameter()) {
                // Parameters will have storage associated with them (to handle byref etc.),
                // so handle those cases specially by storing a pointer instead of a value.
                const IrParameter* irparam = vd->ir.irParam;
                const bool refout = vd->storage_class & (STCref | STCout);
                const bool lazy = vd->storage_class & STClazy;
                const bool byref = irparam->arg->byref;
                const bool isVthisPtr = irparam->isVthis && !byref;
                if (!(refout || (byref && !lazy)) || isVthisPtr) {
                    // This will be copied to the nesting frame.
                    if (lazy)
                        types.push_back(irparam->value->getType()->getContainedType(0));
                    else
                        types.push_back(DtoType(vd->type));
                } else {
                    types.push_back(irparam->value->getType());
                }
            } else if (isSpecialRefVar(vd)) {
                types.push_back(DtoType(vd->type->pointerTo()));
            } else {
                types.push_back(DtoType(vd->type));
            }
            if (Logger::enabled()) {
                Logger::cout() << "Nested var '" << vd->toChars() <<
                    "' of type " << *types.back() << "\n";
            }
        }
//.........这里部分代码省略.........

void DtoCreateNestedContext(FuncDeclaration* fd) {
    Logger::println("DtoCreateNestedContext for %s", fd->toChars());
    LOG_SCOPE

    DtoCreateNestedContextType(fd);

    if (nestedCtx == NCArray) {
        // 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 (par->isClassDeclaration())
                    {
                        // nothing needed
                    }
                    else
                    {
                        break;
                    }

                    par = par->toParent2();
                }
            }
            int nelems = fd->nestedVars.size() + nparelems;

            // make array type for nested vars
            LLType* nestedVarsTy = LLArrayType::get(getVoidPtrType(), nelems);

            // alloca it
            // FIXME align ?
            LLValue* nestedVars = DtoRawAlloca(nestedVarsTy, 0, ".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"));
                } else {
                    src = DtoLoad(src);
                }
                DtoMemCpy(nestedVars, src, DtoConstSize_t(nparelems*PTRSIZE),
                    getABITypeAlign(getVoidPtrType()));
            }

            // 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());
                    DtoAlignedStore(val, gep);
                }
                else
                {
                    Logger::println("nested var:   %s", vd->toChars());
                }

                vd->ir.irLocal->nestedIndex = idx++;
            }
        }
    }
    else if (nestedCtx == NCHybrid) {
        // construct nested variables array
        if (!fd->nestedVars.empty())
        {
            IrFunction* irfunction = fd->ir.irFunc;
//.........这里部分代码省略.........