//===-- toconstelem.cpp ---------------------------------------------------===// // // LDC – the LLVM D compiler // // This file is distributed under the BSD-style LDC license. See the LICENSE // file for details. // //===----------------------------------------------------------------------===// #include "dmd/ctfe.h" #include "dmd/errors.h" #include "dmd/template.h" #include "gen/arrays.h" #include "gen/binops.h" #include "gen/classes.h" #include "gen/complex.h" #include "gen/irstate.h" #include "gen/llvm.h" #include "gen/llvmhelpers.h" #include "gen/logger.h" #include "gen/structs.h" #include "gen/tollvm.h" #include "gen/typinf.h" #include "ir/irfunction.h" #include "ir/irtypeclass.h" #include "ir/irtypestruct.h" /// Emits an LLVM constant corresponding to the expression. /// /// Due to the current implementation of AssocArrayLiteralExp::toElem, the /// implementations have to be able to handle being called on expressions /// that are not actually constant. In such a case, an LLVM undef of the /// expected type should be returned (_not_ null). class ToConstElemVisitor : public Visitor { IRState *p; LLConstant *result; public: explicit ToConstElemVisitor(IRState *p_) : p(p_) {} // Import all functions from class Visitor using Visitor::visit; ////////////////////////////////////////////////////////////////////////////// LLConstant *toConstElem(Expression *e) { result = nullptr; e->accept(this); return result; } ////////////////////////////////////////////////////////////////////////////// void fatalError(Expression *e) { if (!global.gag) { fatal(); } // Do not return null here, as AssocArrayLiteralExp::toElem determines // whether it can allocate the needed arrays statically by just invoking // toConstElem on its key/value expressions, and handling the null value // consequently would require error-prone adaptions in all other code. result = llvm::UndefValue::get(DtoType(e->type)); } ////////////////////////////////////////////////////////////////////////////// void visit(VarExp *e) override { IF_LOG Logger::print("VarExp::toConstElem: %s @ %s\n", e->toChars(), e->type->toChars()); LOG_SCOPE; if (SymbolDeclaration *sdecl = e->var->isSymbolDeclaration()) { // this seems to be the static initialiser for structs Type *sdecltype = sdecl->type->toBasetype(); IF_LOG Logger::print("Sym: type=%s\n", sdecltype->toChars()); assert(sdecltype->ty == Tstruct); TypeStruct *ts = static_cast(sdecltype); DtoResolveStruct(ts->sym); result = getIrAggr(ts->sym)->getDefaultInit(); return; } if (TypeInfoDeclaration *ti = e->var->isTypeInfoDeclaration()) { result = DtoTypeInfoOf(e->loc, ti->tinfo, /*base=*/false); result = DtoBitCast(result, DtoType(e->type)); return; } VarDeclaration *vd = e->var->isVarDeclaration(); if (vd && vd->isConst() && vd->_init) { if (vd->inuse) { e->error("recursive reference `%s`", e->toChars()); result = llvm::UndefValue::get(DtoType(e->type)); } else { vd->inuse++; // return the initializer result = DtoConstInitializer(e->loc, e->type, vd->_init); vd->inuse--; } } // fail else { e->error("non-constant expression `%s`", e->toChars()); result = llvm::UndefValue::get(DtoType(e->type)); } } ////////////////////////////////////////////////////////////////////////////// void visit(IntegerExp *e) override { IF_LOG Logger::print("IntegerExp::toConstElem: %s @ %s\n", e->toChars(), e->type->toChars()); LOG_SCOPE; LLType *t = DtoType(e->type); if (isaPointer(t)) { Logger::println("pointer"); LLConstant *i = LLConstantInt::get( DtoSize_t(), static_cast(e->getInteger()), false); result = llvm::ConstantExpr::getIntToPtr(i, t); } else { assert(llvm::isa(t)); result = LLConstantInt::get(t, static_cast(e->getInteger()), !e->type->isunsigned()); assert(result); IF_LOG Logger::cout() << "value = " << *result << '\n'; } } ////////////////////////////////////////////////////////////////////////////// void visit(RealExp *e) override { IF_LOG Logger::print("RealExp::toConstElem: %s @ %s | %La\n", e->toChars(), e->type->toChars(), e->value); LOG_SCOPE; Type *t = e->type->toBasetype(); result = DtoConstFP(t, e->value); } ////////////////////////////////////////////////////////////////////////////// void visit(NullExp *e) override { IF_LOG Logger::print("NullExp::toConstElem(type=%s): %s\n", e->type->toChars(), e->toChars()); LOG_SCOPE; LLType *t = DtoType(e->type); if (e->type->ty == Tarray) { assert(isaStruct(t)); result = llvm::ConstantAggregateZero::get(t); } else { result = LLConstant::getNullValue(t); } } ////////////////////////////////////////////////////////////////////////////// void visit(ComplexExp *e) override { IF_LOG Logger::print("ComplexExp::toConstElem(): %s @ %s\n", e->toChars(), e->type->toChars()); LOG_SCOPE; result = DtoConstComplex(e->type, e->value.re, e->value.im); } ////////////////////////////////////////////////////////////////////////////// void visit(StringExp *e) override { IF_LOG Logger::print("StringExp::toConstElem: %s @ %s\n", e->toChars(), e->type->toChars()); LOG_SCOPE; Type *const t = e->type->toBasetype(); if (t->ty == Tsarray) { result = buildStringLiteralConstant(e, false); return; } llvm::GlobalVariable *gvar = p->getCachedStringLiteral(e); llvm::ConstantInt *zero = LLConstantInt::get(LLType::getInt32Ty(gIR->context()), 0, false); LLConstant *idxs[2] = {zero, zero}; LLConstant *arrptr = llvm::ConstantExpr::getGetElementPtr( isaPointer(gvar)->getElementType(), gvar, idxs, true); if (t->ty == Tpointer) { result = arrptr; } else if (t->ty == Tarray) { LLConstant *clen = LLConstantInt::get(DtoSize_t(), e->numberOfCodeUnits(), false); result = DtoConstSlice(clen, arrptr, e->type); } else { llvm_unreachable("Unknown type for StringExp."); } } ////////////////////////////////////////////////////////////////////////////// void visit(AddExp *e) override { IF_LOG Logger::print("AddExp::toConstElem: %s @ %s\n", e->toChars(), e->type->toChars()); LOG_SCOPE; // add to pointer Type *t1b = e->e1->type->toBasetype(); if (t1b->ty == Tpointer && e->e2->type->isintegral()) { llvm::Constant *ptr = toConstElem(e->e1); dinteger_t idx = undoStrideMul(e->loc, t1b, e->e2->toInteger()); result = llvm::ConstantExpr::getGetElementPtr( isaPointer(ptr)->getElementType(), ptr, DtoConstSize_t(idx)); return; } visit(static_cast(e)); } void visit(MinExp *e) override { IF_LOG Logger::print("MinExp::toConstElem: %s @ %s\n", e->toChars(), e->type->toChars()); LOG_SCOPE; Type *t1b = e->e1->type->toBasetype(); if (t1b->ty == Tpointer && e->e2->type->isintegral()) { llvm::Constant *ptr = toConstElem(e->e1); dinteger_t idx = undoStrideMul(e->loc, t1b, e->e2->toInteger()); llvm::Constant *negIdx = llvm::ConstantExpr::getNeg(DtoConstSize_t(idx)); result = llvm::ConstantExpr::getGetElementPtr( isaPointer(ptr)->getElementType(), ptr, negIdx); return; } visit(static_cast(e)); } ////////////////////////////////////////////////////////////////////////////// void visit(CastExp *e) override { IF_LOG Logger::print("CastExp::toConstElem: %s @ %s\n", e->toChars(), e->type->toChars()); LOG_SCOPE; LLType *lltype = DtoType(e->type); Type *tb = e->to->toBasetype(); // string literal to dyn array: // reinterpret the string data as an array, calculate the length if (e->e1->op == TOKstring && tb->ty == Tarray) { #if 0 StringExp *strexp = static_cast(e1); size_t datalen = strexp->sz * strexp->len; Type* eltype = tb->nextOf()->toBasetype(); if (datalen % eltype->size() != 0) { error("the sizes don't line up"); return e1->toConstElem(p); } size_t arrlen = datalen / eltype->size(); #endif e->error("ct cast of `string` to dynamic array not fully implemented"); result = toConstElem(e->e1); } // pointer to pointer else if (tb->ty == Tpointer && e->e1->type->toBasetype()->ty == Tpointer) { result = llvm::ConstantExpr::getBitCast(toConstElem(e->e1), lltype); } // global variable to pointer else if (tb->ty == Tpointer && e->e1->op == TOKvar) { VarDeclaration *vd = static_cast(e->e1)->var->isVarDeclaration(); assert(vd); DtoResolveVariable(vd); LLConstant *value = isIrGlobalCreated(vd) ? isaConstant(getIrGlobal(vd)->value) : nullptr; if (!value) { goto Lerr; } Type *type = vd->type->toBasetype(); if (type->ty == Tarray || type->ty == Tdelegate) { LLConstant *idxs[2] = {DtoConstSize_t(0), DtoConstSize_t(1)}; value = llvm::ConstantExpr::getGetElementPtr( isaPointer(value)->getElementType(), value, idxs, true); } result = DtoBitCast(value, DtoType(tb)); } else if (tb->ty == Tclass && e->e1->type->ty == Tclass && e->e1->op == TOKclassreference) { auto cd = static_cast(e->e1)->originalClass(); llvm::Constant *instance = toConstElem(e->e1); if (InterfaceDeclaration *it = static_cast(tb)->sym->isInterfaceDeclaration()) { assert(it->isBaseOf(cd, NULL)); IrTypeClass *typeclass = getIrType(cd->type)->isClass(); // find interface impl size_t i_index = typeclass->getInterfaceIndex(it); assert(i_index != ~0UL); // offset pointer instance = DtoGEP(instance, 0, i_index); } result = DtoBitCast(instance, DtoType(tb)); } else { goto Lerr; } return; Lerr: e->error("cannot cast `%s` to `%s` at compile time", e->e1->type->toChars(), e->type->toChars()); fatalError(e); } ////////////////////////////////////////////////////////////////////////////// void visit(SymOffExp *e) override { IF_LOG Logger::println("SymOffExp::toConstElem: %s @ %s", e->toChars(), e->type->toChars()); LOG_SCOPE; llvm::Constant *base = DtoConstSymbolAddress(e->loc, e->var); if (base == nullptr) { result = llvm::UndefValue::get(DtoType(e->type)); return; } if (e->offset == 0) { result = base; } else { const unsigned elemSize = gDataLayout->getTypeStoreSize(base->getType()->getContainedType(0)); IF_LOG Logger::println("adding offset: %llu (elem size: %u)", static_cast(e->offset), elemSize); if (e->offset % elemSize == 0) { // We can turn this into a "nice" GEP. result = llvm::ConstantExpr::getGetElementPtr(nullptr, base, DtoConstSize_t(e->offset / elemSize)); } else { // Offset isn't a multiple of base type size, just cast to i8* and // apply the byte offset. result = llvm::ConstantExpr::getGetElementPtr(nullptr, DtoBitCast(base, getVoidPtrType()), DtoConstSize_t(e->offset)); } } result = DtoBitCast(result, DtoType(e->type)); } ////////////////////////////////////////////////////////////////////////////// void visit(AddrExp *e) override { IF_LOG Logger::println("AddrExp::toConstElem: %s @ %s", e->toChars(), e->type->toChars()); LOG_SCOPE; // FIXME: this should probably be generalized more so we don't // need to have a case for each thing we can take the address of // address of global variable if (auto vexp = e->e1->isVarExp()) { LLConstant *c = DtoConstSymbolAddress(e->loc, vexp->var); result = c ? DtoBitCast(c, DtoType(e->type)) : nullptr; return; } // address of indexExp if (auto iexp = e->e1->isIndexExp()) { // indexee must be global static array var VarExp *vexp = iexp->e1->isVarExp(); assert(vexp); VarDeclaration *vd = vexp->var->isVarDeclaration(); assert(vd); assert(vd->type->toBasetype()->ty == Tsarray); DtoResolveVariable(vd); assert(isIrGlobalCreated(vd)); // get index LLConstant *index = toConstElem(iexp->e2); assert(index->getType() == DtoSize_t()); // gep LLConstant *idxs[2] = {DtoConstSize_t(0), index}; LLConstant *val = isaConstant(getIrGlobal(vd)->value); val = DtoBitCast(val, DtoType(vd->type->pointerTo())); LLConstant *gep = llvm::ConstantExpr::getGetElementPtr( isaPointer(val)->getElementType(), val, idxs, true); // bitcast to requested type assert(e->type->toBasetype()->ty == Tpointer); result = DtoBitCast(gep, DtoType(e->type)); return; } if (auto se = e->e1->isStructLiteralExp()) { result = p->getStructLiteralConstant(se); if (result) { IF_LOG Logger::cout() << "Returning existing global: " << *result << '\n'; return; } auto globalVar = new llvm::GlobalVariable( p->module, DtoType(se->type), false, llvm::GlobalValue::InternalLinkage, nullptr, ".structliteral"); globalVar->setAlignment(LLMaybeAlign(DtoAlignment(se->type))); p->setStructLiteralConstant(se, globalVar); llvm::Constant *constValue = toConstElem(se); constValue = p->setGlobalVarInitializer(globalVar, constValue, nullptr); p->setStructLiteralConstant(se, constValue); result = constValue; return; } if (e->e1->op == TOKslice || e->e1->op == TOKdotvar) { visit(static_cast(e)); return; } llvm_unreachable("unsupported AddrExp in ToConstElemVisitor"); } ////////////////////////////////////////////////////////////////////////////// void visit(FuncExp *e) override { IF_LOG Logger::print("FuncExp::toConstElem: %s @ %s\n", e->toChars(), e->type->toChars()); LOG_SCOPE; FuncLiteralDeclaration *fd = e->fd; assert(fd); if (fd->tok == TOKreserved && e->type->ty == Tpointer) { // This is a lambda that was inferred to be a function literal instead // of a delegate, so set tok here in order to get correct types/mangling. // Horrible hack, but DMD does the same thing in FuncExp::toElem and // other random places. fd->tok = TOKfunction; fd->vthis = nullptr; } if (fd->tok != TOKfunction) { assert(fd->tok == TOKdelegate || fd->tok == TOKreserved); // Only if the function doesn't access its nested context, we can emit a // constant delegate with context pointer being null. // FIXME: Find a proper way to check whether the context is used. // For now, just enable it for literals declared at module scope. if (!fd->toParent2()->isModule()) { e->error("non-constant nested delegate literal expression `%s`", e->toChars()); fatalError(e); return; } } // We need to actually codegen the function here, as literals are not // added to the module member list. Declaration_codegen(fd, p); result = DtoCallee(fd, false); assert(result); if (fd->tok != TOKfunction) { auto contextPtr = getNullPtr(getVoidPtrType()); result = LLConstantStruct::getAnon(gIR->context(), {contextPtr, result}); } } ////////////////////////////////////////////////////////////////////////////// void visit(ArrayLiteralExp *e) override { IF_LOG Logger::print("ArrayLiteralExp::toConstElem: %s @ %s\n", e->toChars(), e->type->toChars()); LOG_SCOPE; // extract D types Type *bt = e->type->toBasetype(); Type *elemt = bt->nextOf(); // build llvm array type LLArrayType *arrtype = LLArrayType::get(DtoMemType(elemt), e->elements->length); // dynamic arrays can occur here as well ... bool dyn = (bt->ty != Tsarray); llvm::Constant *initval = arrayLiteralToConst(p, e); // if static array, we're done if (!dyn) { result = initval; return; } bool canBeConst = e->type->isConst() || e->type->isImmutable(); auto gvar = new llvm::GlobalVariable( gIR->module, initval->getType(), canBeConst, llvm::GlobalValue::InternalLinkage, initval, ".dynarrayStorage"); gvar->setUnnamedAddr(canBeConst ? llvm::GlobalValue::UnnamedAddr::Global : llvm::GlobalValue::UnnamedAddr::None); llvm::Constant *store = DtoBitCast(gvar, getPtrToType(arrtype)); if (bt->ty == Tpointer) { // we need to return pointer to the static array. result = store; return; } // build a constant dynamic array reference with the .ptr field pointing // into store LLConstant *idxs[2] = {DtoConstUint(0), DtoConstUint(0)}; LLConstant *globalstorePtr = llvm::ConstantExpr::getGetElementPtr( isaPointer(store)->getElementType(), store, idxs, true); result = DtoConstSlice(DtoConstSize_t(e->elements->length), globalstorePtr); } ////////////////////////////////////////////////////////////////////////////// void visit(StructLiteralExp *e) override { // type can legitimately be null for ClassReferenceExp::value. IF_LOG Logger::print("StructLiteralExp::toConstElem: %s @ %s\n", e->toChars(), e->type ? e->type->toChars() : "(null)"); LOG_SCOPE; if (e->useStaticInit) { DtoResolveStruct(e->sd); result = getIrAggr(e->sd)->getDefaultInit(); } else { // make sure the struct is resolved DtoResolveStruct(e->sd); std::map varInits; const size_t nexprs = e->elements->length; for (size_t i = 0; i < nexprs; i++) { if (auto elem = (*e->elements)[i]) { LLConstant *c = toConstElem(elem); // extend i1 to i8 if (c->getType() == LLType::getInt1Ty(p->context())) c = llvm::ConstantExpr::getZExt(c, LLType::getInt8Ty(p->context())); varInits[e->sd->fields[i]] = c; } } result = getIrAggr(e->sd)->createInitializerConstant(varInits); } } ////////////////////////////////////////////////////////////////////////////// void visit(ClassReferenceExp *e) override { IF_LOG Logger::print("ClassReferenceExp::toConstElem: %s @ %s\n", e->toChars(), e->type->toChars()); LOG_SCOPE; ClassDeclaration *origClass = e->originalClass(); DtoResolveClass(origClass); StructLiteralExp *value = e->value; result = p->getStructLiteralConstant(value); if (result) { IF_LOG Logger::cout() << "Using existing global: " << *result << '\n'; } else { auto globalVar = new llvm::GlobalVariable( p->module, getIrType(origClass->type)->isClass()->getMemoryLLType(), false, llvm::GlobalValue::InternalLinkage, nullptr, ".classref"); p->setStructLiteralConstant(value, globalVar); std::map varInits; // Unfortunately, ClassReferenceExp::getFieldAt is badly broken – it // places the base class fields _after_ those of the subclass. { const size_t nexprs = value->elements->length; std::stack classHierachy; ClassDeclaration *cur = origClass; while (cur) { classHierachy.push(cur); cur = cur->baseClass; } size_t i = 0; while (!classHierachy.empty()) { cur = classHierachy.top(); classHierachy.pop(); for (size_t j = 0; j < cur->fields.length; ++j) { if (auto elem = (*value->elements)[i]) { VarDeclaration *field = cur->fields[j]; IF_LOG Logger::println("Getting initializer for: %s", field->toChars()); LOG_SCOPE; varInits[field] = toConstElem(elem); } ++i; } } (void)nexprs; assert(i == nexprs); } llvm::Constant *constValue = getIrAggr(origClass)->createInitializerConstant(varInits); constValue = p->setGlobalVarInitializer(globalVar, constValue, nullptr); p->setStructLiteralConstant(value, constValue); result = constValue; } if (e->type->ty == Tclass) { ClassDeclaration *targetClass = static_cast(e->type)->sym; if (InterfaceDeclaration *it = targetClass->isInterfaceDeclaration()) { assert(it->isBaseOf(origClass, NULL)); // find interface impl size_t i_index = getIrType(origClass->type)->isClass()->getInterfaceIndex(it); assert(i_index != ~0UL); // offset pointer result = DtoGEP(result, 0, i_index); } } assert(e->type->ty == Tclass || e->type->ty == Tenum); result = DtoBitCast(result, DtoType(e->type)); } ////////////////////////////////////////////////////////////////////////////// void visit(VectorExp *e) override { IF_LOG Logger::print("VectorExp::toConstElem: %s @ %s\n", e->toChars(), e->type->toChars()); LOG_SCOPE; TypeVector *tv = static_cast(e->to->toBasetype()); assert(tv->ty == Tvector); const auto elemCount = static_cast(tv->basetype)->dim->toInteger(); // Array literals are assigned element-for-element; other expressions splat // across the whole vector. if (auto ale = e->e1->isArrayLiteralExp()) { llvm::SmallVector elements; elements.reserve(elemCount); for (size_t i = 0; i < elemCount; ++i) { elements.push_back(toConstElem(indexArrayLiteral(ale, i))); } result = llvm::ConstantVector::get(elements); } else { // The AST for // static immutable ubyte16 vec1 = 123; // differs from // static immutable ubyte[16] vec1 = 123; // In the vector case the AST contains an IntegerExp (of type int) and a // CastExp to type ubyte. In the static array case the AST only contains // an IntegerExp of type ubyte. Simply call optimize to get rid of the // cast. // FIXME: Check DMD source to understand why two different ASTs are // constructed. #if LDC_LLVM_VER >= 1100 const auto elementCount = llvm::ElementCount(elemCount, false); #else const auto elementCount = elemCount; #endif result = llvm::ConstantVector::getSplat( elementCount, toConstElem(e->e1->optimize(WANTvalue))); } } ////////////////////////////////////////////////////////////////////////////// void visit(TypeidExp *e) override { IF_LOG Logger::print("TypeidExp::toConstElem: %s @ %s\n", e->toChars(), e->type->toChars()); Type *t = isType(e->obj); if (!t) { visit(static_cast(e)); return; } result = DtoTypeInfoOf(e->loc, t, /*base=*/false); result = DtoBitCast(result, DtoType(e->type)); } ////////////////////////////////////////////////////////////////////////////// void visit(Expression *e) override { e->error("expression `%s` is not a constant", e->toChars()); fatalError(e); } }; LLConstant *toConstElem(Expression *e, IRState *p) { return ToConstElemVisitor(p).toConstElem(e); }