C++ VarDeclaration::isRef方法代码示例

void FuncDeclaration::buildClosure(IRState *irs)
{
    if (needsClosure())
    {   // Generate closure on the heap
        // BUG: doesn't capture variadic arguments passed to this function

#if DMDV2
        /* BUG: doesn't handle destructors for the local variables.
         * The way to do it is to make the closure variables the fields
         * of a class object:
         *    class Closure
         *    {   vtbl[]
         *        monitor
         *        ptr to destructor
         *        sthis
         *        ... closure variables ...
         *        ~this() { call destructor }
         *    }
         */
#endif
        //printf("FuncDeclaration::buildClosure()\n");
        Symbol *sclosure;
        sclosure = symbol_name("__closptr",SCauto,Type::tvoidptr->toCtype());
        sclosure->Sflags |= SFLtrue | SFLfree;
        symbol_add(sclosure);
        irs->sclosure = sclosure;

        unsigned offset = PTRSIZE;      // leave room for previous sthis
        for (size_t i = 0; i < closureVars.dim; i++)
        {   VarDeclaration *v = closureVars[i];
            assert(v->isVarDeclaration());

#if DMDV2
            if (v->needsAutoDtor())
                /* Because the value needs to survive the end of the scope!
                 */
                v->error("has scoped destruction, cannot build closure");
            if (v->isargptr)
                /* See Bugzilla 2479
                 * This is actually a bug, but better to produce a nice
                 * message at compile time rather than memory corruption at runtime
                 */
                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)
//.........这里部分代码省略.........

//.........这里部分代码省略.........
            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);
#if DMDV2
                    AggregateDeclaration* cd = fd->isMember2();
#else
                    ClassDeclaration* cd = fd->isMember2()->isClassDeclaration();
#endif
                    assert(cd);
                    assert(cd->vthis);
                    Logger::println("Indexing to 'this'");
#if DMDV2
                    if (cd->isStructDeclaration())
                        src = DtoExtractValue(thisval, cd->vthis->ir.irField->index, ".vthis");
                    else
#endif
                    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
                    LLValue* value = vd->ir.irLocal->value;
                    if (llvm::isa<llvm::AllocaInst>(llvm::GetUnderlyingObject(value))) {
                        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.
                        assert(!vd->ir.irLocal->byref);
                        DtoStore(DtoLoad(value), gep);
                        gep->takeName(value);
                        vd->ir.irLocal->value = gep;
                    } else {
                        Logger::println("Adding pointer to nested frame");
                        // The parameter value is something else, such as a
                        // passed-in pointer (for 'ref' or 'out' parameters) or
                        // a pointer arg with byval attribute.
                        // Store the address into the frame.
                        assert(vd->ir.irLocal->byref);
                        storeVariable(vd, gep);
                    }
                } else if (vd->isRef() || vd->isOut()) {
                    // This slot is initialized in DtoNestedInit, to handle things like byref foreach variables
                    // which move around in memory.
                    assert(vd->ir.irLocal->byref);
                } else {
                    Logger::println("nested var:   %s", vd->toChars());
                    if (vd->ir.irLocal->value)
                        Logger::cout() << "Pre-existing value: " << *vd->ir.irLocal->value << '\n';
                    assert(!vd->ir.irLocal->value);
                    vd->ir.irLocal->value = gep;
                    assert(!vd->ir.irLocal->byref);
                }

                if (global.params.symdebug) {
                    LLSmallVector<LLValue*, 2> addr;
                    dwarfOpOffset(addr, frameType, vd->ir.irLocal->nestedIndex);
                    DtoDwarfLocalVariable(frame, vd, addr);
                }
            }
        } else if (FuncDeclaration* parFunc = getParentFunc(fd, true)) {
            // Propagate context arg properties if the context arg is passed on unmodified.
            DtoDeclareFunction(parFunc);
            fd->ir.irFunc->frameType = parFunc->ir.irFunc->frameType;
            fd->ir.irFunc->depth = parFunc->ir.irFunc->depth;
        }
    }
    else {
        assert(0 && "Not implemented yet");
    }
}

//.........这里部分代码省略.........
                    DtoDeclareFunction(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()) {
                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.
                    IrParameter * irparam = vd->ir.irParam;
                    LLValue* value = irparam->value;
                    assert(value);
                    LLType* type = value->getType();
                    bool refout = vd->storage_class & (STCref | STCout);
                    bool lazy = vd->storage_class & STClazy;
                    bool byref = irparam->arg->byref;
                #if STRUCTTHISREF
                    bool isVthisPtr = irparam->isVthis && !byref;
                #else
                    bool isVthisPtr = irparam->isVthis;
                #endif
                    if ((!refout && (!byref || lazy)) || isVthisPtr) {
                        // This will be copied to the nesting frame.
                        if (lazy)
                            type = type->getContainedType(0);
                        else
                            type = DtoType(vd->type);
                        vd->ir.irParam->byref = false;
                    } else {
                        vd->ir.irParam->byref = true;
                    }
                    types.push_back(type);
                } else if (vd->isRef() || vd->isOut()) {
                    // Foreach variables can also be by reference, for instance.
                    types.push_back(DtoType(vd->type->pointerTo()));
                    vd->ir.irLocal->byref = true;
                } else {
                    types.push_back(DtoType(vd->type));
                    vd->ir.irLocal->byref = false;
                }
                if (Logger::enabled()) {
                    Logger::println("Nested var: %s", vd->toChars());
                    Logger::cout() << "of type: " << *types.back() << '\n';
                }
            }

            LLStructType* frameType = LLStructType::create(gIR->context(), types,
                                                           std::string("nest.") + fd->toChars());

            Logger::cout() << "frameType = " << *frameType << '\n';

            // Store type in IrFunction
            fd->ir.irFunc->frameType = frameType;
        } else if (FuncDeclaration* parFunc = getParentFunc(fd, true)) {
            // Propagate context arg properties if the context arg is passed on unmodified.
            DtoCreateNestedContextType(parFunc);
            fd->ir.irFunc->frameType = parFunc->ir.irFunc->frameType;
            fd->ir.irFunc->depth = parFunc->ir.irFunc->depth;
        }
    }
    else {
        assert(0 && "Not implemented yet");
    }
}