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swift-mirror/lib/IRGen/GenDecl.cpp
John McCall 06c65464cf Don't crash if an error is emitted by Clang IR-generation. 
Clang IR-generation can fail.  When it does this, it destroys the
module. Previously, we were blithely assuming this couldn't happen,
and so we would crash on the deallocated module.  Delay the
finalization of the Clang code generator until our own module
finalization, which is a more appropriate place for it anyway,
and then just bail out of the last few steps if Clang fails.
2016-05-17 12:38:53 -07:00

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//===--- GenDecl.cpp - IR Generation for Declarations ---------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See http://swift.org/LICENSE.txt for license information
// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
//
// This file implements IR generation for local and global
// declarations in Swift.
//
//===----------------------------------------------------------------------===//
#include "swift/AST/ASTContext.h"
#include "swift/AST/Decl.h"
#include "swift/AST/DiagnosticEngine.h"
#include "swift/AST/DiagnosticsIRGen.h"
#include "swift/AST/IRGenOptions.h"
#include "swift/AST/Module.h"
#include "swift/AST/NameLookup.h"
#include "swift/AST/Pattern.h"
#include "swift/AST/TypeMemberVisitor.h"
#include "swift/AST/Types.h"
#include "swift/Basic/Fallthrough.h"
#include "swift/ClangImporter/ClangModule.h"
#include "swift/SIL/FormalLinkage.h"
#include "swift/SIL/SILDebugScope.h"
#include "swift/SIL/SILModule.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/TypeBuilder.h"
#include "llvm/IR/Value.h"
#include "llvm/IR/GlobalAlias.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/ConvertUTF.h"
#include "Explosion.h"
#include "FixedTypeInfo.h"
#include "GenCall.h"
#include "GenClass.h"
#include "GenObjC.h"
#include "GenOpaque.h"
#include "GenMeta.h"
#include "GenType.h"
#include "IRGenDebugInfo.h"
#include "IRGenFunction.h"
#include "IRGenModule.h"
#include "Linking.h"
using namespace swift;
using namespace irgen;
static bool isTypeMetadataEmittedLazily(CanType type) {
// All classes have eagerly-emitted metadata (at least for now).
if (type.getClassOrBoundGenericClass()) return false;
// Non-nominal metadata (e.g. for builtins) is provided by the runtime and
// doesn't need lazy instantiation.
auto nom = type->getAnyNominal();
if (!nom)
return false;
switch (getDeclLinkage(nom)) {
case FormalLinkage::PublicUnique:
case FormalLinkage::HiddenUnique:
case FormalLinkage::Private:
// Maybe this *should* be lazy for private types?
return false;
case FormalLinkage::PublicNonUnique:
case FormalLinkage::HiddenNonUnique:
return true;
}
llvm_unreachable("bad formal linkage");
}
namespace {
/// Add methods, properties, and protocol conformances from a JITed extension
/// to an ObjC class using the ObjC runtime.
///
/// This must happen after ObjCProtocolInitializerVisitor if any @objc protocols
/// were defined in the TU.
class CategoryInitializerVisitor
: public ClassMemberVisitor<CategoryInitializerVisitor>
{
IRGenFunction &IGF;
IRGenModule &IGM = IGF.IGM;
IRBuilder &Builder = IGF.Builder;
llvm::Constant *class_replaceMethod;
llvm::Constant *class_addProtocol;
llvm::Constant *classMetadata;
llvm::Constant *metaclassMetadata;
public:
CategoryInitializerVisitor(IRGenFunction &IGF, ExtensionDecl *ext)
: IGF(IGF)
{
class_replaceMethod = IGM.getClassReplaceMethodFn();
class_addProtocol = IGM.getClassAddProtocolFn();
CanType origTy = ext->getDeclaredTypeOfContext()->getCanonicalType();
classMetadata =
tryEmitConstantHeapMetadataRef(IGM, origTy, /*allowUninit*/ true);
assert(classMetadata &&
"extended objc class doesn't have constant metadata?!");
classMetadata = llvm::ConstantExpr::getBitCast(classMetadata,
IGM.ObjCClassPtrTy);
metaclassMetadata = IGM.getAddrOfMetaclassObject(
origTy.getClassOrBoundGenericClass(),
NotForDefinition);
metaclassMetadata = llvm::ConstantExpr::getBitCast(metaclassMetadata,
IGM.ObjCClassPtrTy);
// We need to make sure the Objective-C runtime has initialized our
// class. If you try to add or replace a method to a class that isn't
// initialized yet, the Objective-C runtime will crash in the calls
// to class_replaceMethod or class_addProtocol.
Builder.CreateCall(IGM.getGetInitializedObjCClassFn(), classMetadata);
// Register ObjC protocol conformances.
for (auto *p : ext->getLocalProtocols()) {
if (!p->isObjC())
continue;
llvm::Value *protoRef = IGM.getAddrOfObjCProtocolRef(p, NotForDefinition);
auto proto = Builder.CreateLoad(protoRef, IGM.getPointerAlignment());
Builder.CreateCall(class_addProtocol, {classMetadata, proto});
}
}
void visitMembers(ExtensionDecl *ext) {
for (Decl *member : ext->getMembers())
visit(member);
}
void visitTypeDecl(TypeDecl *type) {
// We'll visit nested types separately if necessary.
}
void visitFuncDecl(FuncDecl *method) {
if (!requiresObjCMethodDescriptor(method)) return;
// Don't emit getters/setters for @NSManaged methods.
if (method->getAttrs().hasAttribute<NSManagedAttr>())
return;
llvm::Constant *name, *imp, *types;
emitObjCMethodDescriptorParts(IGM, method,
/*extended*/false,
/*concrete*/true,
name, types, imp);
// When generating JIT'd code, we need to call sel_registerName() to force
// the runtime to unique the selector.
llvm::Value *sel = Builder.CreateCall(IGM.getObjCSelRegisterNameFn(),
name);
llvm::Value *args[] = {
method->isStatic() ? metaclassMetadata : classMetadata,
sel,
imp,
types
};
Builder.CreateCall(class_replaceMethod, args);
}
// Can't be added in an extension.
void visitDestructorDecl(DestructorDecl *dtor) {}
void visitConstructorDecl(ConstructorDecl *constructor) {
if (!requiresObjCMethodDescriptor(constructor)) return;
llvm::Constant *name, *imp, *types;
emitObjCMethodDescriptorParts(IGM, constructor, /*extended*/false,
/*concrete*/true,
name, types, imp);
// When generating JIT'd code, we need to call sel_registerName() to force
// the runtime to unique the selector.
llvm::Value *sel = Builder.CreateCall(IGM.getObjCSelRegisterNameFn(),
name);
llvm::Value *args[] = {
classMetadata,
sel,
imp,
types
};
Builder.CreateCall(class_replaceMethod, args);
}
void visitPatternBindingDecl(PatternBindingDecl *binding) {
// Ignore the PBD and just handle the individual vars.
}
void visitVarDecl(VarDecl *prop) {
if (!requiresObjCPropertyDescriptor(IGM, prop)) return;
// FIXME: register property metadata in addition to the methods.
// ObjC doesn't have a notion of class properties, so we'd only do this
// for instance properties.
// Don't emit getters/setters for @NSManaged properties.
if (prop->getAttrs().hasAttribute<NSManagedAttr>())
return;
llvm::Constant *name, *imp, *types;
emitObjCGetterDescriptorParts(IGM, prop,
name, types, imp);
// When generating JIT'd code, we need to call sel_registerName() to force
// the runtime to unique the selector.
llvm::Value *sel = Builder.CreateCall(IGM.getObjCSelRegisterNameFn(),
name);
auto theClass = prop->isStatic() ? metaclassMetadata : classMetadata;
llvm::Value *getterArgs[] = {theClass, sel, imp, types};
Builder.CreateCall(class_replaceMethod, getterArgs);
if (prop->isSettable(prop->getDeclContext())) {
emitObjCSetterDescriptorParts(IGM, prop,
name, types, imp);
sel = Builder.CreateCall(IGM.getObjCSelRegisterNameFn(),
name);
llvm::Value *setterArgs[] = {theClass, sel, imp, types};
Builder.CreateCall(class_replaceMethod, setterArgs);
}
}
void visitSubscriptDecl(SubscriptDecl *subscript) {
assert(!subscript->isStatic() && "objc doesn't support class subscripts");
if (!requiresObjCSubscriptDescriptor(IGM, subscript)) return;
llvm::Constant *name, *imp, *types;
emitObjCGetterDescriptorParts(IGM, subscript,
name, types, imp);
// When generating JIT'd code, we need to call sel_registerName() to force
// the runtime to unique the selector.
llvm::Value *sel = Builder.CreateCall(IGM.getObjCSelRegisterNameFn(),
name);
llvm::Value *getterArgs[] = {classMetadata, sel, imp, types};
Builder.CreateCall(class_replaceMethod, getterArgs);
if (subscript->isSettable()) {
emitObjCSetterDescriptorParts(IGM, subscript,
name, types, imp);
sel = Builder.CreateCall(IGM.getObjCSelRegisterNameFn(),
name);
llvm::Value *setterArgs[] = {classMetadata, sel, imp, types};
Builder.CreateCall(class_replaceMethod, setterArgs);
}
}
};
/// Create a descriptor for JITed @objc protocol using the ObjC runtime.
class ObjCProtocolInitializerVisitor
: public ClassMemberVisitor<ObjCProtocolInitializerVisitor>
{
IRGenFunction &IGF;
IRGenModule &IGM = IGF.IGM;
IRBuilder &Builder = IGF.Builder;
llvm::Constant *objc_getProtocol,
*objc_allocateProtocol,
*objc_registerProtocol,
*protocol_addMethodDescription,
*protocol_addProtocol;
llvm::Value *NewProto = nullptr;
public:
ObjCProtocolInitializerVisitor(IRGenFunction &IGF)
: IGF(IGF)
{
objc_getProtocol = IGM.getGetObjCProtocolFn();
objc_allocateProtocol = IGM.getAllocateObjCProtocolFn();
objc_registerProtocol = IGM.getRegisterObjCProtocolFn();
protocol_addMethodDescription = IGM.getProtocolAddMethodDescriptionFn();
protocol_addProtocol = IGM.getProtocolAddProtocolFn();
}
void visitMembers(ProtocolDecl *proto) {
// Check if the ObjC runtime already has a descriptor for this
// protocol. If so, use it.
SmallString<32> buf;
auto protocolName
= IGM.getAddrOfGlobalString(proto->getObjCRuntimeName(buf));
auto existing = Builder.CreateCall(objc_getProtocol, protocolName);
auto isNull = Builder.CreateICmpEQ(existing,
llvm::ConstantPointerNull::get(IGM.ProtocolDescriptorPtrTy));
auto existingBB = IGF.createBasicBlock("existing_protocol");
auto newBB = IGF.createBasicBlock("new_protocol");
auto contBB = IGF.createBasicBlock("cont");
Builder.CreateCondBr(isNull, newBB, existingBB);
// Nothing to do if there's already a descriptor.
Builder.emitBlock(existingBB);
Builder.CreateBr(contBB);
Builder.emitBlock(newBB);
// Allocate the protocol descriptor.
NewProto = Builder.CreateCall(objc_allocateProtocol, protocolName);
// Add the parent protocols.
for (auto inherited : proto->getInherited()) {
SmallVector<ProtocolDecl*, 4> protocols;
if (!inherited.getType()->isAnyExistentialType(protocols))
continue;
for (auto parentProto : protocols) {
if (!parentProto->isObjC())
continue;
llvm::Value *parentRef
= IGM.getAddrOfObjCProtocolRef(parentProto, NotForDefinition);
parentRef = IGF.Builder.CreateBitCast(parentRef,
IGM.ProtocolDescriptorPtrTy->getPointerTo());
auto parent = Builder.CreateLoad(parentRef,
IGM.getPointerAlignment());
Builder.CreateCall(protocol_addProtocol, {NewProto, parent});
}
}
// Add the members.
for (Decl *member : proto->getMembers())
visit(member);
// Register it.
Builder.CreateCall(objc_registerProtocol, NewProto);
Builder.CreateBr(contBB);
// Store the reference to the runtime's idea of the protocol descriptor.
Builder.emitBlock(contBB);
auto result = Builder.CreatePHI(IGM.ProtocolDescriptorPtrTy, 2);
result->addIncoming(existing, existingBB);
result->addIncoming(NewProto, newBB);
llvm::Value *ref = IGM.getAddrOfObjCProtocolRef(proto, NotForDefinition);
ref = IGF.Builder.CreateBitCast(ref,
IGM.ProtocolDescriptorPtrTy->getPointerTo());
Builder.CreateStore(result, ref, IGM.getPointerAlignment());
}
void visitTypeDecl(TypeDecl *type) {
// We'll visit nested types separately if necessary.
}
void visitAbstractFunctionDecl(AbstractFunctionDecl *method) {
llvm::Constant *name, *imp, *types;
emitObjCMethodDescriptorParts(IGM, method, /*extended*/true,
/*concrete*/false,
name, types, imp);
// When generating JIT'd code, we need to call sel_registerName() to force
// the runtime to unique the selector.
llvm::Value *sel = Builder.CreateCall(IGM.getObjCSelRegisterNameFn(), name);
llvm::Value *args[] = {
NewProto, sel, types,
// required?
llvm::ConstantInt::get(IGM.ObjCBoolTy,
!method->getAttrs().hasAttribute<OptionalAttr>()),
// instance?
llvm::ConstantInt::get(IGM.ObjCBoolTy,
isa<ConstructorDecl>(method) || method->isInstanceMember()),
};
Builder.CreateCall(protocol_addMethodDescription, args);
}
void visitPatternBindingDecl(PatternBindingDecl *binding) {
// Ignore the PBD and just handle the individual vars.
}
void visitAbstractStorageDecl(AbstractStorageDecl *prop) {
// TODO: Add properties to protocol.
llvm::Constant *name, *imp, *types;
emitObjCGetterDescriptorParts(IGM, prop,
name, types, imp);
// When generating JIT'd code, we need to call sel_registerName() to force
// the runtime to unique the selector.
llvm::Value *sel = Builder.CreateCall(IGM.getObjCSelRegisterNameFn(), name);
llvm::Value *getterArgs[] = {
NewProto, sel, types,
// required?
llvm::ConstantInt::get(IGM.ObjCBoolTy,
!prop->getAttrs().hasAttribute<OptionalAttr>()),
// instance?
llvm::ConstantInt::get(IGM.ObjCBoolTy,
prop->isInstanceMember()),
};
Builder.CreateCall(protocol_addMethodDescription, getterArgs);
if (prop->isSettable(nullptr)) {
emitObjCSetterDescriptorParts(IGM, prop, name, types, imp);
sel = Builder.CreateCall(IGM.getObjCSelRegisterNameFn(), name);
llvm::Value *setterArgs[] = {
NewProto, sel, types,
// required?
llvm::ConstantInt::get(IGM.ObjCBoolTy,
!prop->getAttrs().hasAttribute<OptionalAttr>()),
// instance?
llvm::ConstantInt::get(IGM.ObjCBoolTy,
prop->isInstanceMember()),
};
Builder.CreateCall(protocol_addMethodDescription, setterArgs);
}
}
};
} // end anonymous namespace
namespace {
class PrettySourceFileEmission : public llvm::PrettyStackTraceEntry {
const SourceFile &SF;
public:
explicit PrettySourceFileEmission(const SourceFile &SF) : SF(SF) {}
virtual void print(raw_ostream &os) const override {
os << "While emitting IR for source file " << SF.getFilename() << '\n';
}
};
} // end anonymous namespace
/// Emit all the top-level code in the source file.
void IRGenModule::emitSourceFile(SourceFile &SF, unsigned StartElem) {
PrettySourceFileEmission StackEntry(SF);
// Emit types and other global decls.
for (unsigned i = StartElem, e = SF.Decls.size(); i != e; ++i)
emitGlobalDecl(SF.Decls[i]);
for (auto *localDecl : SF.LocalTypeDecls)
emitGlobalDecl(localDecl);
SF.forAllVisibleModules([&](swift::Module::ImportedModule import) {
swift::Module *next = import.second;
if (next->getName() == SF.getParentModule()->getName())
return;
next->collectLinkLibraries([this](LinkLibrary linkLib) {
this->addLinkLibrary(linkLib);
});
});
if (ObjCInterop)
this->addLinkLibrary(LinkLibrary("objc", LibraryKind::Library));
}
/// Collect elements of an already-existing global list with the given
/// \c name into \c list.
///
/// We use this when Clang code generation might populate the list.
static void collectGlobalList(IRGenModule &IGM,
SmallVectorImpl<llvm::WeakVH> &list,
StringRef name) {
if (auto *existing = IGM.Module.getGlobalVariable(name)) {
auto *globals = cast<llvm::ConstantArray>(existing->getInitializer());
for (auto &use : globals->operands()) {
auto *global = use.get();
list.push_back(global);
}
existing->eraseFromParent();
}
std::for_each(list.begin(), list.end(),
[](const llvm::WeakVH &global) {
assert(!isa<llvm::GlobalValue>(global) ||
!cast<llvm::GlobalValue>(global)->isDeclaration() &&
"all globals in the 'used' list must be definitions");
});
}
/// Emit a global list, i.e. a global constant array holding all of a
/// list of values. Generally these lists are for various LLVM
/// metadata or runtime purposes.
static llvm::GlobalVariable *
emitGlobalList(IRGenModule &IGM, ArrayRef<llvm::WeakVH> handles,
StringRef name, StringRef section,
llvm::GlobalValue::LinkageTypes linkage,
llvm::Type *eltTy,
bool isConstant) {
// Do nothing if the list is empty.
if (handles.empty()) return nullptr;
// For global lists that actually get linked (as opposed to notional
// ones like @llvm.used), it's important to set an explicit alignment
// so that the linker doesn't accidentally put padding in the list.
Alignment alignment = IGM.getPointerAlignment();
// We have an array of value handles, but we need an array of constants.
SmallVector<llvm::Constant*, 8> elts;
elts.reserve(handles.size());
for (auto &handle : handles) {
auto elt = cast<llvm::Constant>(&*handle);
if (elt->getType() != eltTy)
elt = llvm::ConstantExpr::getBitCast(elt, eltTy);
elts.push_back(elt);
}
auto varTy = llvm::ArrayType::get(eltTy, elts.size());
auto init = llvm::ConstantArray::get(varTy, elts);
auto var = new llvm::GlobalVariable(IGM.Module, varTy, isConstant, linkage,
init, name);
var->setSection(section);
var->setAlignment(alignment.getValue());
// Mark the variable as used if doesn't have external linkage.
// (Note that we'd specifically like to not put @llvm.used in itself.)
if (llvm::GlobalValue::isLocalLinkage(linkage))
IGM.addUsedGlobal(var);
return var;
}
void IRGenModule::emitRuntimeRegistration() {
// Duck out early if we have nothing to register.
if (ProtocolConformances.empty()
&& RuntimeResolvableTypes.empty()
&& (!ObjCInterop || (ObjCProtocols.empty() &&
ObjCClasses.empty() &&
ObjCCategoryDecls.empty())))
return;
// Find the entry point.
SILFunction *EntryPoint =
getSILModule().lookUpFunction(SWIFT_ENTRY_POINT_FUNCTION);
// If we're debugging, we probably don't have a main. Find a
// function marked with the LLDBDebuggerFunction attribute instead.
if (!EntryPoint && Context.LangOpts.DebuggerSupport) {
for (SILFunction &SF : getSILModule()) {
if (SF.hasLocation()) {
if (Decl* D = SF.getLocation().getAsASTNode<Decl>()) {
if (FuncDecl *FD = dyn_cast<FuncDecl>(D)) {
if (FD->getAttrs().hasAttribute<LLDBDebuggerFunctionAttr>()) {
EntryPoint = &SF;
break;
}
}
}
}
}
}
if (!EntryPoint)
return;
llvm::Function *EntryFunction = Module.getFunction(EntryPoint->getName());
if (!EntryFunction)
return;
// Create a new function to contain our logic.
auto fnTy = llvm::FunctionType::get(VoidTy, /*varArg*/ false);
auto RegistrationFunction = llvm::Function::Create(fnTy,
llvm::GlobalValue::PrivateLinkage,
"runtime_registration",
getModule());
RegistrationFunction->setAttributes(constructInitialAttributes());
// Insert a call into the entry function.
{
llvm::BasicBlock *EntryBB = &EntryFunction->getEntryBlock();
llvm::BasicBlock::iterator IP = EntryBB->getFirstInsertionPt();
IRBuilder Builder(getLLVMContext());
Builder.llvm::IRBuilderBase::SetInsertPoint(EntryBB, IP);
Builder.CreateCall(RegistrationFunction, {});
}
IRGenFunction RegIGF(*this, RegistrationFunction);
// Register ObjC protocols, classes, and extensions we added.
if (ObjCInterop) {
if (!ObjCProtocols.empty()) {
// We need to initialize ObjC protocols in inheritance order, parents
// first.
llvm::DenseSet<ProtocolDecl*> protos;
for (auto &proto : ObjCProtocols)
protos.insert(proto.first);
llvm::SmallVector<ProtocolDecl*, 4> protoInitOrder;
std::function<void(ProtocolDecl*)> orderProtocol
= [&](ProtocolDecl *proto) {
// Recursively put parents first.
for (auto &inherited : proto->getInherited()) {
SmallVector<ProtocolDecl*, 4> parents;
if (!inherited.getType()->isAnyExistentialType(parents))
continue;
for (auto parent : parents)
orderProtocol(parent);
}
// Skip if we don't need to reify this protocol.
auto found = protos.find(proto);
if (found == protos.end())
return;
protos.erase(found);
protoInitOrder.push_back(proto);
};
while (!protos.empty()) {
orderProtocol(*protos.begin());
}
// Visit the protocols in the order we established.
for (auto *proto : protoInitOrder) {
ObjCProtocolInitializerVisitor(RegIGF)
.visitMembers(proto);
}
}
for (llvm::WeakVH &ObjCClass : ObjCClasses) {
RegIGF.Builder.CreateCall(getInstantiateObjCClassFn(), {ObjCClass});
}
for (ExtensionDecl *ext : ObjCCategoryDecls) {
CategoryInitializerVisitor(RegIGF, ext).visitMembers(ext);
}
}
// Register Swift protocol conformances if we added any.
if (!ProtocolConformances.empty()) {
llvm::Constant *conformances = emitProtocolConformances();
llvm::Constant *beginIndices[] = {
llvm::ConstantInt::get(Int32Ty, 0),
llvm::ConstantInt::get(Int32Ty, 0),
};
auto begin = llvm::ConstantExpr::getGetElementPtr(
/*Ty=*/nullptr, conformances, beginIndices);
llvm::Constant *endIndices[] = {
llvm::ConstantInt::get(Int32Ty, 0),
llvm::ConstantInt::get(Int32Ty, ProtocolConformances.size()),
};
auto end = llvm::ConstantExpr::getGetElementPtr(
/*Ty=*/nullptr, conformances, endIndices);
RegIGF.Builder.CreateCall(getRegisterProtocolConformancesFn(), {begin, end});
}
if (!RuntimeResolvableTypes.empty()) {
llvm::Constant *records = emitTypeMetadataRecords();
llvm::Constant *beginIndices[] = {
llvm::ConstantInt::get(Int32Ty, 0),
llvm::ConstantInt::get(Int32Ty, 0),
};
auto begin = llvm::ConstantExpr::getGetElementPtr(
/*Ty=*/nullptr, records, beginIndices);
llvm::Constant *endIndices[] = {
llvm::ConstantInt::get(Int32Ty, 0),
llvm::ConstantInt::get(Int32Ty, RuntimeResolvableTypes.size()),
};
auto end = llvm::ConstantExpr::getGetElementPtr(
/*Ty=*/nullptr, records, endIndices);
RegIGF.Builder.CreateCall(getRegisterTypeMetadataRecordsFn(), {begin, end});
}
RegIGF.Builder.CreateRetVoid();
}
/// Add the given global value to @llvm.used.
///
/// This value must have a definition by the time the module is finalized.
void IRGenModule::addUsedGlobal(llvm::GlobalValue *global) {
LLVMUsed.push_back(global);
}
/// Add the given global value to @llvm.compiler.used.
///
/// This value must have a definition by the time the module is finalized.
void IRGenModule::addCompilerUsedGlobal(llvm::GlobalValue *global) {
LLVMCompilerUsed.push_back(global);
}
/// Add the given global value to the Objective-C class list.
void IRGenModule::addObjCClass(llvm::Constant *classPtr, bool nonlazy) {
ObjCClasses.push_back(classPtr);
if (nonlazy)
ObjCNonLazyClasses.push_back(classPtr);
}
/// Add the given protocol conformance to the list of conformances for which
/// runtime records will be emitted in this translation unit.
void IRGenModule::addProtocolConformanceRecord(
NormalProtocolConformance *conformance) {
ProtocolConformances.push_back(conformance);
}
static bool
hasExplicitProtocolConformance(NominalTypeDecl *decl) {
auto conformances = decl->getAllConformances();
for (auto conformance : conformances) {
// inherited protocols do not emit explicit conformance records
// TODO any special handling required for Specialized conformances?
if (conformance->getKind() == ProtocolConformanceKind::Inherited)
continue;
auto P = conformance->getProtocol();
// @objc protocols do not have conformance records
if (P->isObjC())
continue;
// neither does AnyObject
if (P->getKnownProtocolKind().hasValue() &&
*P->getKnownProtocolKind() == KnownProtocolKind::AnyObject)
continue;
return true;
}
return false;
}
void IRGenModule::addRuntimeResolvableType(CanType type) {
// Don't emit type metadata records for types that can be found in the protocol
// conformance table as the runtime will search both tables when resolving a
// type by name.
if (auto nom = type->getAnyNominal()) {
if (!hasExplicitProtocolConformance(nom))
RuntimeResolvableTypes.push_back(type);
}
}
void IRGenModule::emitGlobalLists() {
if (ObjCInterop) {
assert(TargetInfo.OutputObjectFormat == llvm::Triple::MachO);
// Objective-C class references go in a variable with a meaningless
// name but a magic section.
emitGlobalList(*this, ObjCClasses, "objc_classes",
"__DATA, __objc_classlist, regular, no_dead_strip",
llvm::GlobalValue::InternalLinkage,
Int8PtrTy,
false);
// So do categories.
emitGlobalList(*this, ObjCCategories, "objc_categories",
"__DATA, __objc_catlist, regular, no_dead_strip",
llvm::GlobalValue::InternalLinkage,
Int8PtrTy,
false);
// Emit nonlazily realized class references in a second magic section to make
// sure they are realized by the Objective-C runtime before any instances
// are allocated.
emitGlobalList(*this, ObjCNonLazyClasses, "objc_non_lazy_classes",
"__DATA, __objc_nlclslist, regular, no_dead_strip",
llvm::GlobalValue::InternalLinkage,
Int8PtrTy,
false);
}
// @llvm.used
// Collect llvm.used globals already in the module (coming from ClangCodeGen).
collectGlobalList(*this, LLVMUsed, "llvm.used");
emitGlobalList(*this, LLVMUsed, "llvm.used", "llvm.metadata",
llvm::GlobalValue::AppendingLinkage,
Int8PtrTy,
false);
// Collect llvm.compiler.used globals already in the module (coming
// from ClangCodeGen).
collectGlobalList(*this, LLVMCompilerUsed, "llvm.compiler.used");
emitGlobalList(*this, LLVMCompilerUsed, "llvm.compiler.used", "llvm.metadata",
llvm::GlobalValue::AppendingLinkage,
Int8PtrTy,
false);
}
void IRGenerator::emitGlobalTopLevel() {
// Generate order numbers for the functions in the SIL module that
// correspond to definitions in the LLVM module.
unsigned nextOrderNumber = 0;
for (auto &silFn : PrimaryIGM->getSILModule().getFunctions()) {
// Don't bother adding external declarations to the function order.
if (!silFn.isDefinition()) continue;
FunctionOrder.insert(std::make_pair(&silFn, nextOrderNumber++));
}
for (SILGlobalVariable &v : PrimaryIGM->getSILModule().getSILGlobals()) {
Decl *decl = v.getDecl();
CurrentIGMPtr IGM = getGenModule(decl ? decl->getDeclContext() : nullptr);
IGM->emitSILGlobalVariable(&v);
}
PrimaryIGM->emitCoverageMapping();
// Emit SIL functions.
bool isWholeModule = PrimaryIGM->getSILModule().isWholeModule();
for (SILFunction &f : PrimaryIGM->getSILModule()) {
// Only eagerly emit functions that are externally visible.
if (!isPossiblyUsedExternally(f.getLinkage(), isWholeModule))
continue;
CurrentIGMPtr IGM = getGenModule(&f);
IGM->emitSILFunction(&f);
}
// Emit static initializers.
for (auto Iter : *this) {
IRGenModule *IGM = Iter.second;
IGM->emitSILStaticInitializers();
}
// Emit witness tables.
for (SILWitnessTable &wt : PrimaryIGM->getSILModule().getWitnessTableList()) {
CurrentIGMPtr IGM = getGenModule(wt.getConformance()->getDeclContext());
IGM->emitSILWitnessTable(&wt);
}
for (auto Iter : *this) {
IRGenModule *IGM = Iter.second;
IGM->finishEmitAfterTopLevel();
}
}
void IRGenModule::finishEmitAfterTopLevel() {
// Emit the implicit import of the swift standard library.
if (DebugInfo) {
std::pair<swift::Identifier, swift::SourceLoc> AccessPath[] = {
{ Context.StdlibModuleName, swift::SourceLoc() }
};
auto Imp = ImportDecl::create(Context,
getSwiftModule(),
SourceLoc(),
ImportKind::Module, SourceLoc(),
AccessPath);
DebugInfo->emitImport(Imp);
}
// Emit external definitions used by this module.
for (auto def : Context.ExternalDefinitions) {
emitExternalDefinition(def);
}
}
static void emitLazyTypeMetadata(IRGenModule &IGM, CanType type) {
auto decl = type.getAnyNominal();
assert(decl);
if (auto sd = dyn_cast<StructDecl>(decl)) {
return emitStructMetadata(IGM, sd);
} else if (auto ed = dyn_cast<EnumDecl>(decl)) {
emitEnumMetadata(IGM, ed);
} else if (auto pd = dyn_cast<ProtocolDecl>(decl)) {
IGM.emitProtocolDecl(pd);
} else {
llvm_unreachable("should not have enqueued a class decl here!");
}
}
void IRGenerator::emitProtocolConformances() {
for (auto &m : *this) {
m.second->emitProtocolConformances();
}
}
void IRGenerator::emitTypeMetadataRecords() {
for (auto &m : *this) {
m.second->emitTypeMetadataRecords();
}
}
/// Emit any lazy definitions (of globals or functions or whatever
/// else) that we require.
void IRGenerator::emitLazyDefinitions() {
while (!LazyTypeMetadata.empty() ||
!LazyFunctionDefinitions.empty() ||
!LazyFieldTypeAccessors.empty()) {
// Emit any lazy type metadata we require.
while (!LazyTypeMetadata.empty()) {
CanType type = LazyTypeMetadata.pop_back_val();
assert(isTypeMetadataEmittedLazily(type));
auto nom = type->getAnyNominal();
CurrentIGMPtr IGM = getGenModule(nom->getDeclContext());
emitLazyTypeMetadata(*IGM.get(), type);
}
while (!LazyFieldTypeAccessors.empty()) {
auto accessor = LazyFieldTypeAccessors.pop_back_val();
emitFieldTypeAccessor(*accessor.IGM, accessor.type, accessor.fn,
accessor.fieldTypes);
}
// Emit any lazy function definitions we require.
while (!LazyFunctionDefinitions.empty()) {
SILFunction *f = LazyFunctionDefinitions.pop_back_val();
CurrentIGMPtr IGM = getGenModule(f);
assert(!isPossiblyUsedExternally(f->getLinkage(),
IGM->getSILModule().isWholeModule())
&& "function with externally-visible linkage emitted lazily?");
IGM->emitSILFunction(f);
}
}
}
/// Emit symbols for eliminated dead methods, which can still be referenced
/// from other modules. This happens e.g. if a public class contains a (dead)
/// private method.
void IRGenModule::emitVTableStubs() {
llvm::Function *stub = nullptr;
for (auto I = getSILModule().zombies_begin();
I != getSILModule().zombies_end(); ++I) {
const SILFunction &F = *I;
if (! F.isExternallyUsedSymbol())
continue;
if (!stub) {
// Create a single stub function which calls swift_deletedMethodError().
stub = llvm::Function::Create(llvm::FunctionType::get(VoidTy, false),
llvm::GlobalValue::InternalLinkage,
"_swift_dead_method_stub");
stub->setAttributes(constructInitialAttributes());
Module.getFunctionList().push_back(stub);
stub->setCallingConv(DefaultCC);
auto *entry = llvm::BasicBlock::Create(getLLVMContext(), "entry", stub);
auto *errorFunc = getDeletedMethodErrorFn();
llvm::CallInst::Create(errorFunc, ArrayRef<llvm::Value *>(), "", entry);
new llvm::UnreachableInst(getLLVMContext(), entry);
}
// For each eliminated method symbol create an alias to the stub.
llvm::GlobalAlias::create(llvm::GlobalValue::ExternalLinkage, F.getName(),
stub);
}
}
void IRGenModule::emitTypeVerifier() {
// Look up the types to verify.
SmallVector<CanType, 4> TypesToVerify;
for (auto name : IRGen.Opts.VerifyTypeLayoutNames) {
// Look up the name in the module.
SmallVector<ValueDecl*, 1> lookup;
swift::Module *M = getSwiftModule();
M->lookupMember(lookup, M, DeclName(Context.getIdentifier(name)),
Identifier());
if (lookup.empty()) {
Context.Diags.diagnose(SourceLoc(), diag::type_to_verify_not_found,
name);
continue;
}
TypeDecl *typeDecl = nullptr;
for (auto decl : lookup) {
if (auto td = dyn_cast<TypeDecl>(decl)) {
if (typeDecl) {
Context.Diags.diagnose(SourceLoc(), diag::type_to_verify_ambiguous,
name);
goto next;
}
typeDecl = td;
break;
}
}
if (!typeDecl) {
Context.Diags.diagnose(SourceLoc(), diag::type_to_verify_not_found, name);
continue;
}
{
auto type = typeDecl->getDeclaredInterfaceType();
if (type->hasTypeParameter()) {
Context.Diags.diagnose(SourceLoc(), diag::type_to_verify_dependent,
name);
continue;
}
TypesToVerify.push_back(type->getCanonicalType());
}
next:;
}
if (TypesToVerify.empty())
return;
// Find the entry point.
SILFunction *EntryPoint =
getSILModule().lookUpFunction(SWIFT_ENTRY_POINT_FUNCTION);
if (!EntryPoint)
return;
llvm::Function *EntryFunction = Module.getFunction(EntryPoint->getName());
if (!EntryFunction)
return;
// Create a new function to contain our logic.
auto fnTy = llvm::FunctionType::get(VoidTy, /*varArg*/ false);
auto VerifierFunction = llvm::Function::Create(fnTy,
llvm::GlobalValue::PrivateLinkage,
"type_verifier",
getModule());
VerifierFunction->setAttributes(constructInitialAttributes());
// Insert a call into the entry function.
{
llvm::BasicBlock *EntryBB = &EntryFunction->getEntryBlock();
llvm::BasicBlock::iterator IP = EntryBB->getFirstInsertionPt();
IRBuilder Builder(getLLVMContext());
Builder.llvm::IRBuilderBase::SetInsertPoint(EntryBB, IP);
Builder.CreateCall(VerifierFunction, {});
}
IRGenFunction VerifierIGF(*this, VerifierFunction);
emitTypeLayoutVerifier(VerifierIGF, TypesToVerify);
VerifierIGF.Builder.CreateRetVoid();
}
/// Get SIL-linkage for something that's not required to be visible
/// and doesn't actually need to be uniqued.
static SILLinkage getNonUniqueSILLinkage(FormalLinkage linkage,
ForDefinition_t forDefinition) {
switch (linkage) {
case FormalLinkage::PublicUnique:
case FormalLinkage::PublicNonUnique:
return (forDefinition ? SILLinkage::Shared : SILLinkage::PublicExternal);
case FormalLinkage::HiddenUnique:
case FormalLinkage::HiddenNonUnique:
return (forDefinition ? SILLinkage::Shared : SILLinkage::HiddenExternal);
case FormalLinkage::Private:
return SILLinkage::Private;
}
llvm_unreachable("bad formal linkage");
}
static SILLinkage getConformanceLinkage(IRGenModule &IGM,
const ProtocolConformance *conf) {
if (auto wt = IGM.getSILModule().lookUpWitnessTable(conf)) {
return wt->getLinkage();
} else {
return SILLinkage::PublicExternal;
}
}
SILLinkage LinkEntity::getLinkage(IRGenModule &IGM,
ForDefinition_t forDefinition) const {
switch (getKind()) {
// Most type metadata depend on the formal linkage of their type.
case Kind::ValueWitnessTable:
case Kind::TypeMangling:
return getSILLinkage(getTypeLinkage(getType()), forDefinition);
case Kind::TypeMetadata:
switch (getMetadataAddress()) {
case TypeMetadataAddress::FullMetadata:
// The full metadata object is private to the containing module.
return SILLinkage::Private;
case TypeMetadataAddress::AddressPoint:
return getSILLinkage(getTypeLinkage(getType()), forDefinition);
}
// ...but we don't actually expose individual value witnesses (right now).
case Kind::ValueWitness:
return getNonUniqueSILLinkage(getTypeLinkage(getType()), forDefinition);
// Foreign type metadata candidates are always shared; the runtime
// does the uniquing.
case Kind::ForeignTypeMetadataCandidate:
return SILLinkage::Shared;
case Kind::TypeMetadataAccessFunction:
case Kind::TypeMetadataLazyCacheVariable:
switch (getTypeMetadataAccessStrategy(IGM, getType())) {
case MetadataAccessStrategy::PublicUniqueAccessor:
return getSILLinkage(FormalLinkage::PublicUnique, forDefinition);
case MetadataAccessStrategy::HiddenUniqueAccessor:
return getSILLinkage(FormalLinkage::HiddenUnique, forDefinition);
case MetadataAccessStrategy::PrivateAccessor:
return getSILLinkage(FormalLinkage::Private, forDefinition);
case MetadataAccessStrategy::NonUniqueAccessor:
return SILLinkage::Shared;
}
llvm_unreachable("bad metadata access kind");
case Kind::ObjCClassRef:
return SILLinkage::Private;
case Kind::WitnessTableOffset:
case Kind::Function:
case Kind::Other:
case Kind::ObjCClass:
case Kind::ObjCMetaclass:
case Kind::SwiftMetaclassStub:
case Kind::FieldOffset:
case Kind::NominalTypeDescriptor:
case Kind::ProtocolDescriptor:
return getSILLinkage(getDeclLinkage(getDecl()), forDefinition);
case Kind::DirectProtocolWitnessTable:
case Kind::ProtocolWitnessTableAccessFunction:
return getConformanceLinkage(IGM, getProtocolConformance());
case Kind::ProtocolWitnessTableLazyAccessFunction:
case Kind::ProtocolWitnessTableLazyCacheVariable:
if (getTypeLinkage(getType()) == FormalLinkage::Private ||
getConformanceLinkage(IGM, getProtocolConformance())
== SILLinkage::Private) {
return SILLinkage::Private;
} else {
return SILLinkage::Shared;
}
case Kind::AssociatedTypeMetadataAccessFunction:
case Kind::AssociatedTypeWitnessTableAccessFunction:
case Kind::GenericProtocolWitnessTableCache:
case Kind::GenericProtocolWitnessTableInstantiationFunction:
return SILLinkage::Private;
case Kind::SILFunction:
return getSILFunction()->getEffectiveSymbolLinkage();
case Kind::SILGlobalVariable:
return getSILGlobalVariable()->getLinkage();
}
llvm_unreachable("bad link entity kind");
}
static bool isAvailableExternally(IRGenModule &IGM, DeclContext *dc) {
dc = dc->getModuleScopeContext();
if (isa<ClangModuleUnit>(dc) ||
dc == IGM.getSILModule().getAssociatedContext())
return false;
return true;
}
static bool isAvailableExternally(IRGenModule &IGM, Decl *decl) {
return isAvailableExternally(IGM, decl->getDeclContext());
}
static bool isAvailableExternally(IRGenModule &IGM, Type type) {
if (auto decl = type->getAnyNominal())
return isAvailableExternally(IGM, decl->getDeclContext());
return true;
}
bool LinkEntity::isAvailableExternally(IRGenModule &IGM) const {
switch (getKind()) {
case Kind::ValueWitnessTable:
case Kind::TypeMetadata:
return ::isAvailableExternally(IGM, getType());
case Kind::ForeignTypeMetadataCandidate:
assert(!::isAvailableExternally(IGM, getType()));
return false;
case Kind::ObjCClass:
case Kind::ObjCMetaclass:
// FIXME: Removing this triggers a linker bug
return true;
case Kind::SwiftMetaclassStub:
case Kind::NominalTypeDescriptor:
case Kind::ProtocolDescriptor:
return ::isAvailableExternally(IGM, getDecl());
case Kind::DirectProtocolWitnessTable:
return ::isAvailableExternally(IGM, getProtocolConformance()->getDeclContext());
case Kind::ObjCClassRef:
case Kind::TypeMangling:
case Kind::ValueWitness:
case Kind::WitnessTableOffset:
case Kind::TypeMetadataAccessFunction:
case Kind::TypeMetadataLazyCacheVariable:
case Kind::Function:
case Kind::Other:
case Kind::FieldOffset:
case Kind::ProtocolWitnessTableAccessFunction:
case Kind::ProtocolWitnessTableLazyAccessFunction:
case Kind::ProtocolWitnessTableLazyCacheVariable:
case Kind::AssociatedTypeMetadataAccessFunction:
case Kind::AssociatedTypeWitnessTableAccessFunction:
case Kind::GenericProtocolWitnessTableCache:
case Kind::GenericProtocolWitnessTableInstantiationFunction:
case Kind::SILFunction:
case Kind::SILGlobalVariable:
llvm_unreachable("Relative reference to unsupported link entity");
}
llvm_unreachable("bad link entity kind");
}
static std::pair<llvm::GlobalValue::LinkageTypes,
llvm::GlobalValue::VisibilityTypes>
getIRLinkage(IRGenModule &IGM,
SILLinkage linkage, ForDefinition_t isDefinition,
bool isWeakImported) {
#define RESULT(LINKAGE, VISIBILITY) \
{ llvm::GlobalValue::LINKAGE##Linkage, \
llvm::GlobalValue::VISIBILITY##Visibility }
// Public visibility depends on the target object format.
llvm::GlobalValue::VisibilityTypes PublicDefinitionVisibility;
switch (IGM.TargetInfo.OutputObjectFormat) {
case llvm::Triple::ELF:
// Use protected visibility for public symbols we define.
// ld.so doesn't support relative relocations at load time, which interferes
// with our metadata formats.
PublicDefinitionVisibility = llvm::GlobalValue::ProtectedVisibility;
break;
default:
// Default visibility should suffice for other object formats.
PublicDefinitionVisibility = llvm::GlobalValue::DefaultVisibility;
break;
}
switch (linkage) {
case SILLinkage::Public:
return {llvm::GlobalValue::ExternalLinkage, PublicDefinitionVisibility};
case SILLinkage::Shared:
case SILLinkage::SharedExternal:
return RESULT(LinkOnceODR, Hidden);
case SILLinkage::Hidden:
return RESULT(External, Hidden);
case SILLinkage::Private:
if (IGM.IRGen.hasMultipleIGMs()) {
// In case of multiple llvm modules (in multi-threaded compilation) all
// private decls must be visible from other files.
return RESULT(External, Hidden);
}
return RESULT(Internal, Default);
case SILLinkage::PublicExternal:
if (isDefinition) {
return RESULT(AvailableExternally, Default);
}
if (isWeakImported)
return RESULT(ExternalWeak, Default);
return RESULT(External, Default);
case SILLinkage::HiddenExternal:
case SILLinkage::PrivateExternal:
if (isDefinition)
return RESULT(AvailableExternally, Hidden);
return RESULT(External, Hidden);
}
llvm_unreachable("bad SIL linkage");
}
/// Given that we're going to define a global value but already have a
/// forward-declaration of it, update its linkage.
static void updateLinkageForDefinition(IRGenModule &IGM,
llvm::GlobalValue *global,
const LinkEntity &entity) {
// TODO: there are probably cases where we can avoid redoing the
// entire linkage computation.
auto linkage = getIRLinkage(
IGM,
entity.getLinkage(IGM, ForDefinition),
ForDefinition,
entity.isWeakImported(IGM.getSwiftModule()));
global->setLinkage(linkage.first);
global->setVisibility(linkage.second);
// Everything externally visible is considered used in Swift.
// That mostly means we need to be good at not marking things external.
//
// Exclude "main", because it should naturally be used, and because adding it
// to llvm.used leaves a dangling use when the REPL attempts to discard
// intermediate mains.
if (LinkInfo::isUsed(linkage.first, linkage.second) &&
global->getName() != SWIFT_ENTRY_POINT_FUNCTION) {
IGM.addUsedGlobal(global);
}
}
LinkInfo LinkInfo::get(IRGenModule &IGM, const LinkEntity &entity,
ForDefinition_t isDefinition) {
LinkInfo result;
entity.mangle(result.Name);
std::tie(result.Linkage, result.Visibility) =
getIRLinkage(IGM, entity.getLinkage(IGM, isDefinition),
isDefinition,
entity.isWeakImported(IGM.getSwiftModule()));
result.ForDefinition = isDefinition;
return result;
}
static bool isPointerTo(llvm::Type *ptrTy, llvm::Type *objTy) {
return cast<llvm::PointerType>(ptrTy)->getElementType() == objTy;
}
/// Get or create an LLVM function with these linkage rules.
llvm::Function *LinkInfo::createFunction(IRGenModule &IGM,
llvm::FunctionType *fnType,
llvm::CallingConv::ID cc,
const llvm::AttributeSet &attrs,
llvm::Function *insertBefore) {
llvm::Function *existing = IGM.Module.getFunction(getName());
if (existing) {
if (isPointerTo(existing->getType(), fnType))
return cast<llvm::Function>(existing);
IGM.error(SourceLoc(),
"program too clever: function collides with existing symbol "
+ getName());
// Note that this will implicitly unique if the .unique name is also taken.
existing->setName(getName() + ".unique");
}
llvm::Function *fn
= llvm::Function::Create(fnType, getLinkage(), getName());
if (insertBefore) {
IGM.Module.getFunctionList().insert(insertBefore->getIterator(), fn);
} else {
IGM.Module.getFunctionList().push_back(fn);
}
fn->setVisibility(getVisibility());
fn->setCallingConv(cc);
auto initialAttrs = IGM.constructInitialAttributes();
// Merge initialAttrs with attrs.
auto updatedAttrs = attrs.addAttributes(IGM.getLLVMContext(),
llvm::AttributeSet::FunctionIndex, initialAttrs);
if (!updatedAttrs.isEmpty())
fn->setAttributes(updatedAttrs);
// Everything externally visible is considered used in Swift.
// That mostly means we need to be good at not marking things external.
//
// Exclude "main", because it should naturally be used, and because adding it
// to llvm.used leaves a dangling use when the REPL attempts to discard
// intermediate mains.
if (isUsed() &&
getName() != SWIFT_ENTRY_POINT_FUNCTION) {
IGM.addUsedGlobal(fn);
}
return fn;
}
bool LinkInfo::isUsed(llvm::GlobalValue::LinkageTypes Linkage,
llvm::GlobalValue::VisibilityTypes Visibility) {
// Everything externally visible is considered used in Swift.
// That mostly means we need to be good at not marking things external.
return Linkage == llvm::GlobalValue::ExternalLinkage &&
(Visibility == llvm::GlobalValue::DefaultVisibility ||
Visibility == llvm::GlobalValue::ProtectedVisibility);
}
/// Get or create an LLVM global variable with these linkage rules.
llvm::GlobalVariable *LinkInfo::createVariable(IRGenModule &IGM,
llvm::Type *storageType,
Alignment alignment,
DebugTypeInfo DbgTy,
Optional<SILLocation> DebugLoc,
StringRef DebugName) {
llvm::GlobalValue *existingValue = IGM.Module.getNamedGlobal(getName());
if (existingValue) {
auto existingVar = dyn_cast<llvm::GlobalVariable>(existingValue);
if (existingVar && isPointerTo(existingVar->getType(), storageType))
return existingVar;
IGM.error(SourceLoc(),
"program too clever: variable collides with existing symbol "
+ getName());
// Note that this will implicitly unique if the .unique name is also taken.
existingValue->setName(getName() + ".unique");
}
auto var = new llvm::GlobalVariable(IGM.Module, storageType,
/*constant*/ false,
getLinkage(), /*initializer*/ nullptr,
getName());
var->setVisibility(getVisibility());
var->setAlignment(alignment.getValue());
// Everything externally visible is considered used in Swift.
// That mostly means we need to be good at not marking things external.
if (isUsed()) {
IGM.addUsedGlobal(var);
}
if (IGM.DebugInfo && !DbgTy.isNull() && ForDefinition)
IGM.DebugInfo->emitGlobalVariableDeclaration(
var, DebugName.empty() ? getName() : DebugName, getName(), DbgTy,
DebugLoc);
return var;
}
/// Emit a global declaration.
void IRGenModule::emitGlobalDecl(Decl *D) {
switch (D->getKind()) {
case DeclKind::Extension:
return emitExtension(cast<ExtensionDecl>(D));
case DeclKind::Protocol:
return emitProtocolDecl(cast<ProtocolDecl>(D));
case DeclKind::PatternBinding:
// The global initializations are in SIL.
return;
case DeclKind::Param:
llvm_unreachable("there are no global function parameters");
case DeclKind::Subscript:
llvm_unreachable("there are no global subscript operations");
case DeclKind::EnumCase:
case DeclKind::EnumElement:
llvm_unreachable("there are no global enum elements");
case DeclKind::Constructor:
llvm_unreachable("there are no global constructor");
case DeclKind::Destructor:
llvm_unreachable("there are no global destructor");
case DeclKind::TypeAlias:
case DeclKind::GenericTypeParam:
case DeclKind::AssociatedType:
case DeclKind::IfConfig:
return;
case DeclKind::Enum:
return emitEnumDecl(cast<EnumDecl>(D));
case DeclKind::Struct:
return emitStructDecl(cast<StructDecl>(D));
case DeclKind::Class:
return emitClassDecl(cast<ClassDecl>(D));
// These declarations are only included in the debug info.
case DeclKind::Import:
if (DebugInfo)
DebugInfo->emitImport(cast<ImportDecl>(D));
return;
// We emit these as part of the PatternBindingDecl.
case DeclKind::Var:
return;
case DeclKind::Func:
// Handled in SIL.
return;
case DeclKind::TopLevelCode:
// All the top-level code will be lowered separately.
return;
// Operator decls aren't needed for IRGen.
case DeclKind::InfixOperator:
case DeclKind::PrefixOperator:
case DeclKind::PostfixOperator:
return;
case DeclKind::Module:
return;
}
llvm_unreachable("bad decl kind!");
}
void IRGenModule::emitExternalDefinition(Decl *D) {
switch (D->getKind()) {
case DeclKind::Extension:
case DeclKind::PatternBinding:
case DeclKind::EnumCase:
case DeclKind::EnumElement:
case DeclKind::TopLevelCode:
case DeclKind::TypeAlias:
case DeclKind::GenericTypeParam:
case DeclKind::AssociatedType:
case DeclKind::Import:
case DeclKind::Subscript:
case DeclKind::Destructor:
case DeclKind::InfixOperator:
case DeclKind::PrefixOperator:
case DeclKind::PostfixOperator:
case DeclKind::IfConfig:
case DeclKind::Param:
case DeclKind::Module:
llvm_unreachable("Not a valid external definition for IRgen");
case DeclKind::Var:
assert(D->getClangDecl() && "Not a valid external var for IRGen");
return emitClangDecl(const_cast<clang::Decl *>(D->getClangDecl()));
case DeclKind::Func:
if (auto *clangDecl = D->getClangDecl())
emitClangDecl(const_cast<clang::Decl *>(clangDecl));
break;
case DeclKind::Constructor:
// Do nothing.
break;
// No need to eagerly emit Swift metadata for external types.
case DeclKind::Struct:
case DeclKind::Enum:
case DeclKind::Class:
case DeclKind::Protocol:
break;
}
}
Address IRGenModule::getAddrOfSILGlobalVariable(SILGlobalVariable *var,
const TypeInfo &ti,
ForDefinition_t forDefinition) {
LinkEntity entity = LinkEntity::forSILGlobalVariable(var);
ResilienceExpansion expansion = getResilienceExpansionForLayout(var);
llvm::Type *storageType;
Size fixedSize;
Alignment fixedAlignment;
// If the type has a fixed size, allocate static storage. Otherwise, allocate
// a fixed-size buffer and possibly heap-allocate a payload at runtime if the
// runtime size of the type does not fit in the buffer.
if (ti.isFixedSize(expansion)) {
auto &fixedTI = cast<FixedTypeInfo>(ti);
storageType = fixedTI.getStorageType();
fixedSize = fixedTI.getFixedSize();
fixedAlignment = fixedTI.getFixedAlignment();
} else {
storageType = getFixedBufferTy();
fixedSize = Size(DataLayout.getTypeAllocSize(storageType));
fixedAlignment = Alignment(DataLayout.getABITypeAlignment(storageType));
}
// Check whether we've created the global variable already.
// FIXME: We should integrate this into the LinkEntity cache more cleanly.
auto gvar = Module.getGlobalVariable(var->getName(), /*allowInternal*/ true);
if (gvar) {
if (forDefinition)
updateLinkageForDefinition(*this, gvar, entity);
llvm::Constant *addr = gvar;
if (storageType != gvar->getType()->getElementType()) {
auto *expectedTy = storageType->getPointerTo();
addr = llvm::ConstantExpr::getBitCast(addr, expectedTy);
}
return Address(addr, Alignment(gvar->getAlignment()));
}
LinkInfo link = LinkInfo::get(*this, entity, forDefinition);
if (var->getDecl()) {
// If we have the VarDecl, use it for more accurate debugging information.
DebugTypeInfo DbgTy(var->getDecl(),
var->getLoweredType().getSwiftType(),
storageType, fixedSize, fixedAlignment);
gvar = link.createVariable(*this, storageType, fixedAlignment,
DbgTy, SILLocation(var->getDecl()),
var->getDecl()->getName().str());
} else {
// There is no VarDecl for a SILGlobalVariable, and thus also no context.
DeclContext *DeclCtx = nullptr;
DebugTypeInfo DbgTy(var->getLoweredType().getSwiftRValueType(),
storageType, fixedSize, fixedAlignment, DeclCtx);
Optional<SILLocation> loc;
if (var->hasLocation())
loc = var->getLocation();
gvar = link.createVariable(*this, storageType, fixedAlignment,
DbgTy, loc, var->getName());
}
// Set the alignment from the TypeInfo.
Address gvarAddr = Address(gvar, fixedAlignment);
gvar->setAlignment(fixedAlignment.getValue());
return gvarAddr;
}
/// Return True if the function \p f is a 'readonly' function. Checking
/// for the SIL @effects(readonly) attribute is not enough because this
/// definition does not match the definition of the LLVM readonly function
/// attribute. In this function we do the actual check.
static bool isReadOnlyFunction(SILFunction *f) {
// Check if the function has any 'owned' parameters. Owned parameters may
// call the destructor of the object which could violate the readonly-ness
// of the function.
if (f->hasOwnedParameters() || f->hasIndirectResults())
return false;
auto Eff = f->getEffectsKind();
return Eff == EffectsKind::ReadNone ||
Eff == EffectsKind::ReadOnly;
}
/// Find the entry point for a SIL function.
llvm::Function *IRGenModule::getAddrOfSILFunction(SILFunction *f,
ForDefinition_t forDefinition) {
LinkEntity entity = LinkEntity::forSILFunction(f);
// Check whether we've created the function already.
// FIXME: We should integrate this into the LinkEntity cache more cleanly.
llvm::Function *fn = Module.getFunction(f->getName());
if (fn) {
if (forDefinition) updateLinkageForDefinition(*this, fn, entity);
return fn;
}
bool hasOrderNumber = f->isDefinition();
unsigned orderNumber = ~0U;
llvm::Function *insertBefore = nullptr;
// If the SIL function has a definition, we should have an order
// number for it; make sure to insert it in that position relative
// to other ordered functions.
if (hasOrderNumber) {
orderNumber = IRGen.getFunctionOrder(f);
if (auto emittedFunctionIterator
= EmittedFunctionsByOrder.findLeastUpperBound(orderNumber))
insertBefore = *emittedFunctionIterator;
// Also, if we have a lazy definition for it, be sure to queue that up.
if (!forDefinition &&
!isPossiblyUsedExternally(f->getLinkage(),
getSILModule().isWholeModule()))
IRGen.addLazyFunction(f);
}
llvm::AttributeSet attrs;
llvm::FunctionType *fnType = getFunctionType(f->getLoweredFunctionType(),
attrs);
auto cc = expandCallingConv(*this, f->getRepresentation());
LinkInfo link = LinkInfo::get(*this, entity, forDefinition);
if (f->getInlineStrategy() == NoInline) {
attrs = attrs.addAttribute(fnType->getContext(),
llvm::AttributeSet::FunctionIndex, llvm::Attribute::NoInline);
}
if (isReadOnlyFunction(f)) {
attrs = attrs.addAttribute(fnType->getContext(),
llvm::AttributeSet::FunctionIndex, llvm::Attribute::ReadOnly);
}
fn = link.createFunction(*this, fnType, cc, attrs, insertBefore);
// If we have an order number for this function, set it up as appropriate.
if (hasOrderNumber) {
EmittedFunctionsByOrder.insert(orderNumber, fn);
}
return fn;
}
static llvm::GlobalVariable *createGOTEquivalent(IRGenModule &IGM,
llvm::Constant *global,
StringRef globalName) {
auto gotEquivalent = new llvm::GlobalVariable(IGM.Module,
global->getType(),
/*constant*/ true,
llvm::GlobalValue::PrivateLinkage,
global,
llvm::Twine("got.") + globalName);
gotEquivalent->setUnnamedAddr(true);
return gotEquivalent;
}
static llvm::Constant *getElementBitCast(llvm::Constant *ptr,
llvm::Type *newEltType) {
auto ptrType = cast<llvm::PointerType>(ptr->getType());
if (ptrType->getElementType() == newEltType) {
return ptr;
} else {
auto newPtrType = newEltType->getPointerTo(ptrType->getAddressSpace());
return llvm::ConstantExpr::getBitCast(ptr, newPtrType);
}
}
/// Return a reference to an object that's suitable for being used for
/// the given kind of reference.
///
/// Note that, if the requested reference kind is a relative reference.
/// the returned constant will not actually be a relative reference.
/// To form the actual relative reference, you must pass the returned
/// result to emitRelativeReference, passing the correct base-address
/// information.
ConstantReference
IRGenModule::getAddrOfLLVMVariable(LinkEntity entity, Alignment alignment,
llvm::Type *definitionType,
llvm::Type *defaultType,
DebugTypeInfo debugType,
SymbolReferenceKind refKind) {
switch (refKind) {
case SymbolReferenceKind::Relative_Direct:
case SymbolReferenceKind::Far_Relative_Direct:
assert(definitionType == nullptr);
// FIXME: don't just fall through; force the creation of a weak
// definition so that we can emit a relative reference.
SWIFT_FALLTHROUGH;
case SymbolReferenceKind::Absolute:
return { getAddrOfLLVMVariable(entity, alignment, definitionType,
defaultType, debugType),
ConstantReference::Direct };
case SymbolReferenceKind::Relative_Indirectable:
case SymbolReferenceKind::Far_Relative_Indirectable:
assert(definitionType == nullptr);
return getAddrOfLLVMVariableOrGOTEquivalent(entity, alignment, defaultType);
}
llvm_unreachable("bad reference kind");
}
/// A convenient wrapper around getAddrOfLLVMVariable which uses the
/// default type as the definition type.
llvm::Constant *
IRGenModule::getAddrOfLLVMVariable(LinkEntity entity, Alignment alignment,
ForDefinition_t forDefinition,
llvm::Type *defaultType,
DebugTypeInfo debugType) {
llvm::Type *definitionType = (forDefinition ? defaultType : nullptr);
return getAddrOfLLVMVariable(entity, alignment, definitionType,
defaultType, debugType);
}
/// Get or create an llvm::GlobalVariable.
///
/// If a definition type is given, the result will always be an
/// llvm::GlobalVariable of that type. Otherwise, the result will
/// have type pointerToDefaultType and may involve bitcasts.
llvm::Constant *
IRGenModule::getAddrOfLLVMVariable(LinkEntity entity, Alignment alignment,
llvm::Type *definitionType,
llvm::Type *defaultType,
DebugTypeInfo DbgTy) {
// This function assumes that 'globals' only contains GlobalValue
// values for the entities that it will look up.
auto &entry = GlobalVars[entity];
if (entry) {
auto existing = cast<llvm::GlobalValue>(entry);
// If we're looking to define something, we may need to replace a
// forward declaration.
if (definitionType) {
assert(existing->isDeclaration() && "already defined");
assert(entry->getType()->getPointerElementType() == defaultType);
updateLinkageForDefinition(*this, existing, entity);
// If the type is right, we're done.
if (definitionType == defaultType)
return entry;
// Fall out to the case below, clearing the name so that
// createVariable doesn't detect a collision.
entry->setName("");
// Otherwise, we have a previous declaration or definition which
// we need to ensure has the right type.
} else {
return getElementBitCast(entry, defaultType);
}
}
ForDefinition_t forDefinition = (ForDefinition_t) (definitionType != nullptr);
LinkInfo link = LinkInfo::get(*this, entity, forDefinition);
// Clang may have defined the variable already.
if (auto existing = Module.getNamedGlobal(link.getName()))
return getElementBitCast(existing, defaultType);
// If we're not defining the object now, forward declare it with the default
// type.
if (!definitionType) definitionType = defaultType;
// Create the variable.
auto var = link.createVariable(*this, definitionType, alignment, DbgTy);
// If we have an existing entry, destroy it, replacing it with the
// new variable.
if (entry) {
auto existing = cast<llvm::GlobalValue>(entry);
auto castVar = getElementBitCast(var, defaultType);
existing->replaceAllUsesWith(castVar);
existing->eraseFromParent();
}
// If there's also an existing GOT-equivalent entry, rewrite it too, since
// LLVM won't recognize a global with bitcasts in its initializers as GOT-
// equivalent. rdar://problem/22388190
auto foundGOTEntry = GlobalGOTEquivalents.find(entity);
if (foundGOTEntry != GlobalGOTEquivalents.end() && foundGOTEntry->second) {
auto existingGOTEquiv = cast<llvm::GlobalVariable>(foundGOTEntry->second);
// Make a new GOT equivalent referring to the new variable with its
// definition type.
auto newGOTEquiv = createGOTEquivalent(*this, var, var->getName());
auto castGOTEquiv = llvm::ConstantExpr::getBitCast(newGOTEquiv,
existingGOTEquiv->getType());
existingGOTEquiv->replaceAllUsesWith(castGOTEquiv);
existingGOTEquiv->eraseFromParent();
GlobalGOTEquivalents[entity] = newGOTEquiv;
}
// Cache and return.
entry = var;
return var;
}
/// Get or create a "GOT equivalent" llvm::GlobalVariable, if applicable.
///
/// Creates a private, unnamed constant containing the address of another
/// global variable. LLVM can replace relative references to this variable with
/// relative references to the GOT entry for the variable in the object file.
ConstantReference
IRGenModule::getAddrOfLLVMVariableOrGOTEquivalent(LinkEntity entity,
Alignment alignment,
llvm::Type *defaultType) {
// Ensure the variable is at least forward-declared.
if (entity.isForeignTypeMetadataCandidate()) {
auto foreignCandidate
= getAddrOfForeignTypeMetadataCandidate(entity.getType());
(void)foreignCandidate;
} else {
getAddrOfLLVMVariable(entity, alignment, /*definitionType*/ nullptr,
defaultType, DebugTypeInfo());
}
// Guess whether a global entry is a definition from this TU. This isn't
// bulletproof, but at the point we emit conformance tables, we're far enough
// along that we should have emitted any metadata objects we were going to.
auto isDefinition = [&](llvm::Constant *global) -> bool {
// We only emit aliases for definitions. (An extern alias would be an
// extern global.)
if (isa<llvm::GlobalAlias>(global))
return true;
// Global vars are definitions if they have an initializer.
if (auto var = dyn_cast<llvm::GlobalVariable>(global))
return var->hasInitializer();
// Assume anything else isn't a definition.
return false;
};
// If the variable isn't public, or has already been defined in this TU,
// then it definitely doesn't need a GOT entry, and we can
// relative-reference it directly.
//
// TODO: Internal symbols from other TUs we know are destined to be linked
// into the same image as us could use direct
// relative references too, to avoid producing unnecessary GOT entries in
// the final image.
auto entry = GlobalVars[entity];
if (!entity.isAvailableExternally(*this) || isDefinition(entry)) {
// FIXME: Relative references to aliases break MC on 32-bit Mach-O
// platforms (rdar://problem/22450593 ), so substitute an alias with its
// aliasee to work around that.
if (auto alias = dyn_cast<llvm::GlobalAlias>(entry))
entry = alias->getAliasee();
return {entry, ConstantReference::Direct};
}
auto &gotEntry = GlobalGOTEquivalents[entity];
if (gotEntry) {
return {gotEntry, ConstantReference::Indirect};
}
// Look up the global variable.
auto global = cast<llvm::GlobalValue>(entry);
// Use it as the initializer for an anonymous constant. LLVM can treat this as
// equivalent to the global's GOT entry.
llvm::SmallString<64> name;
entity.mangle(name);
auto gotEquivalent = createGOTEquivalent(*this, global, name);
gotEntry = gotEquivalent;
return {gotEquivalent, ConstantReference::Indirect};
}
namespace {
struct TypeEntityInfo {
ProtocolConformanceFlags flags;
LinkEntity entity;
llvm::Type *defaultTy, *defaultPtrTy;
};
} // end anonymous namespace
static TypeEntityInfo
getTypeEntityInfo(IRGenModule &IGM, CanType conformingType) {
TypeMetadataRecordKind typeKind;
Optional<LinkEntity> entity;
llvm::Type *defaultTy, *defaultPtrTy;
auto nom = conformingType->getAnyNominal();
auto clas = dyn_cast<ClassDecl>(nom);
if (nom->isGenericContext() ||
(clas && doesClassMetadataRequireDynamicInitialization(IGM, clas))) {
// Conformances for generics and concrete subclasses of generics
// are represented by referencing the nominal type descriptor.
typeKind = TypeMetadataRecordKind::UniqueNominalTypeDescriptor;
entity = LinkEntity::forNominalTypeDescriptor(nom);
defaultTy = IGM.NominalTypeDescriptorTy;
defaultPtrTy = IGM.NominalTypeDescriptorPtrTy;
} else if (clas) {
if (clas->isForeign()) {
typeKind = TypeMetadataRecordKind::NonuniqueDirectType;
entity = LinkEntity::forForeignTypeMetadataCandidate(conformingType);
defaultTy = IGM.TypeMetadataStructTy;
defaultPtrTy = IGM.TypeMetadataPtrTy;
} else {
// TODO: We should indirectly reference classes. For now directly
// reference the class object, which is totally wrong for ObjC interop.
typeKind = TypeMetadataRecordKind::UniqueDirectClass;
if (hasKnownSwiftMetadata(IGM, clas))
entity = LinkEntity::forTypeMetadata(
conformingType,
TypeMetadataAddress::AddressPoint,
/*isPattern*/ false);
else
entity = LinkEntity::forObjCClass(clas);
defaultTy = IGM.TypeMetadataStructTy;
defaultPtrTy = IGM.TypeMetadataPtrTy;
}
} else {
// Metadata for Clang types should be uniqued like foreign classes.
if (nom->hasClangNode()) {
typeKind = TypeMetadataRecordKind::NonuniqueDirectType;
entity = LinkEntity::forForeignTypeMetadataCandidate(conformingType);
defaultTy = IGM.TypeMetadataStructTy;
defaultPtrTy = IGM.TypeMetadataPtrTy;
} else {
// We can reference the canonical metadata for native value types
// directly.
typeKind = TypeMetadataRecordKind::UniqueDirectType;
entity = LinkEntity::forTypeMetadata(
conformingType,
TypeMetadataAddress::AddressPoint,
/*isPattern*/ false);
defaultTy = IGM.TypeMetadataStructTy;
defaultPtrTy = IGM.TypeMetadataPtrTy;
}
}
auto flags = ProtocolConformanceFlags().withTypeKind(typeKind);
return {flags, *entity, defaultTy, defaultPtrTy};
}
/// Form an LLVM constant for the relative distance between a reference
/// (appearing at gep (0, indices) of `base`) and `target`.
llvm::Constant *
IRGenModule::emitRelativeReference(ConstantReference target,
llvm::Constant *base,
ArrayRef<unsigned> baseIndices) {
llvm::Constant *relativeAddr =
emitDirectRelativeReference(target.getValue(), base, baseIndices);
// If the reference is indirect, flag it by setting the low bit.
// (All of the base, direct target, and GOT entry need to be pointer-aligned
// for this to be OK.)
if (target.isIndirect()) {
relativeAddr = llvm::ConstantExpr::getAdd(relativeAddr,
llvm::ConstantInt::get(RelativeAddressTy, 1));
}
return relativeAddr;
}
/// Form an LLVM constant for the relative distance between a reference
/// (appearing at gep (0, indices...) of `base`) and `target`. For now,
/// for this to succeed portably, both need to be globals defined in the
/// current translation unit.
llvm::Constant *
IRGenModule::emitDirectRelativeReference(llvm::Constant *target,
llvm::Constant *base,
ArrayRef<unsigned> baseIndices) {
// Convert the target to an integer.
auto targetAddr = llvm::ConstantExpr::getPtrToInt(target, SizeTy);
SmallVector<llvm::Constant*, 4> indices;
indices.push_back(llvm::ConstantInt::get(Int32Ty, 0));
for (unsigned baseIndex : baseIndices) {
indices.push_back(llvm::ConstantInt::get(Int32Ty, baseIndex));
};
// Drill down to the appropriate address in the base, then convert
// that to an integer.
auto baseElt = llvm::ConstantExpr::getInBoundsGetElementPtr(
base->getType()->getPointerElementType(), base, indices);
auto baseAddr = llvm::ConstantExpr::getPtrToInt(baseElt, SizeTy);
// The relative address is the difference between those.
auto relativeAddr = llvm::ConstantExpr::getSub(targetAddr, baseAddr);
// Relative addresses can be 32-bit even on 64-bit platforms.
if (SizeTy != RelativeAddressTy)
relativeAddr = llvm::ConstantExpr::getTrunc(relativeAddr,
RelativeAddressTy);
return relativeAddr;
}
/// Emit the protocol conformance list and return it.
llvm::Constant *IRGenModule::emitProtocolConformances() {
std::string sectionName;
switch (TargetInfo.OutputObjectFormat) {
case llvm::Triple::MachO:
sectionName = "__TEXT, __swift2_proto, regular, no_dead_strip";
break;
case llvm::Triple::ELF:
sectionName = ".swift2_protocol_conformances";
break;
case llvm::Triple::COFF:
sectionName = ".sw2prtc";
break;
default:
llvm_unreachable("Don't know how to emit protocol conformances for "
"the selected object format.");
}
// Do nothing if the list is empty.
if (ProtocolConformances.empty())
return nullptr;
// Define the global variable for the conformance list.
// We have to do this before defining the initializer since the entries will
// contain offsets relative to themselves.
auto arrayTy = llvm::ArrayType::get(ProtocolConformanceRecordTy,
ProtocolConformances.size());
// FIXME: This needs to be a linker-local symbol in order for Darwin ld to
// resolve relocations relative to it.
auto var = new llvm::GlobalVariable(Module, arrayTy,
/*isConstant*/ true,
llvm::GlobalValue::PrivateLinkage,
/*initializer*/ nullptr,
"\x01l_protocol_conformances");
SmallVector<llvm::Constant*, 8> elts;
for (auto *conformance : ProtocolConformances) {
auto descriptorRef = getAddrOfLLVMVariableOrGOTEquivalent(
LinkEntity::forProtocolDescriptor(conformance->getProtocol()),
getPointerAlignment(), ProtocolDescriptorStructTy);
auto typeEntity = getTypeEntityInfo(*this,
conformance->getType()->getCanonicalType());
auto flags = typeEntity.flags
.withConformanceKind(ProtocolConformanceReferenceKind::WitnessTable);
// If the conformance is in this object's table, then the witness table
// should also be in this object file, so we can always directly reference
// it.
// TODO: Should use accessor kind for lazy conformances
// TODO: Produce a relative reference to a private generator function
// if the witness table requires lazy initialization, instantiation, or
// conditional conformance checking.
auto witnessTableVar = getAddrOfWitnessTable(conformance);
auto witnessTableRef =
ConstantReference(witnessTableVar, ConstantReference::Direct);
auto typeRef = getAddrOfLLVMVariableOrGOTEquivalent(
typeEntity.entity, getPointerAlignment(), typeEntity.defaultTy);
unsigned arrayIdx = elts.size();
llvm::Constant *recordFields[] = {
emitRelativeReference(descriptorRef, var, { arrayIdx, 0 }),
emitRelativeReference(typeRef, var, { arrayIdx, 1 }),
emitRelativeReference(witnessTableRef, var, { arrayIdx, 2 }),
llvm::ConstantInt::get(Int32Ty, flags.getValue()),
};
auto record = llvm::ConstantStruct::get(ProtocolConformanceRecordTy,
recordFields);
elts.push_back(record);
}
auto initializer = llvm::ConstantArray::get(arrayTy, elts);
var->setInitializer(initializer);
var->setSection(sectionName);
var->setAlignment(getPointerAlignment().getValue());
addUsedGlobal(var);
return var;
}
/// Emit type metadata for types that might not have explicit protocol conformances.
llvm::Constant *IRGenModule::emitTypeMetadataRecords() {
std::string sectionName;
switch (TargetInfo.OutputObjectFormat) {
case llvm::Triple::MachO:
sectionName = "__TEXT, __swift2_types, regular, no_dead_strip";
break;
case llvm::Triple::ELF:
sectionName = ".swift2_type_metadata";
break;
case llvm::Triple::COFF:
sectionName = ".sw2tymd";
break;
default:
llvm_unreachable("Don't know how to emit type metadata table for "
"the selected object format.");
}
// Do nothing if the list is empty.
if (RuntimeResolvableTypes.empty())
return nullptr;
// Define the global variable for the conformance list.
// We have to do this before defining the initializer since the entries will
// contain offsets relative to themselves.
auto arrayTy = llvm::ArrayType::get(TypeMetadataRecordTy,
RuntimeResolvableTypes.size());
// FIXME: This needs to be a linker-local symbol in order for Darwin ld to
// resolve relocations relative to it.
auto var = new llvm::GlobalVariable(Module, arrayTy,
/*isConstant*/ true,
llvm::GlobalValue::PrivateLinkage,
/*initializer*/ nullptr,
"\x01l_type_metadata_table");
SmallVector<llvm::Constant *, 8> elts;
for (auto type : RuntimeResolvableTypes) {
auto typeEntity = getTypeEntityInfo(*this, type);
auto typeRef = getAddrOfLLVMVariableOrGOTEquivalent(
typeEntity.entity, getPointerAlignment(), typeEntity.defaultTy);
unsigned arrayIdx = elts.size();
llvm::Constant *recordFields[] = {
emitRelativeReference(typeRef, var, { arrayIdx, 0 }),
llvm::ConstantInt::get(Int32Ty, typeEntity.flags.getValue()),
};
auto record = llvm::ConstantStruct::get(TypeMetadataRecordTy,
recordFields);
elts.push_back(record);
}
auto initializer = llvm::ConstantArray::get(arrayTy, elts);
var->setInitializer(initializer);
var->setSection(sectionName);
var->setAlignment(getPointerAlignment().getValue());
addUsedGlobal(var);
return var;
}
/// Fetch a global reference to a reference to the given Objective-C class.
/// The result is of type ObjCClassPtrTy->getPointerTo().
Address IRGenModule::getAddrOfObjCClassRef(ClassDecl *theClass) {
assert(ObjCInterop && "getting address of ObjC class ref in no-interop mode");
Alignment alignment = getPointerAlignment();
LinkEntity entity = LinkEntity::forObjCClassRef(theClass);
DebugTypeInfo DbgTy(theClass, ObjCClassPtrTy->getPointerTo(),
getPointerSize(), alignment);
auto addr = getAddrOfLLVMVariable(entity, alignment, NotForDefinition,
ObjCClassPtrTy, DbgTy);
// Define it lazily.
if (auto global = dyn_cast<llvm::GlobalVariable>(addr)) {
if (global->isDeclaration()) {
global->setSection("__DATA,__objc_classrefs,regular,no_dead_strip");
global->setLinkage(llvm::GlobalVariable::PrivateLinkage);
global->setExternallyInitialized(true);
global->setInitializer(getAddrOfObjCClass(theClass, NotForDefinition));
addCompilerUsedGlobal(global);
}
}
return Address(addr, alignment);
}
/// Fetch a global reference to the given Objective-C class. The
/// result is of type ObjCClassPtrTy.
llvm::Constant *IRGenModule::getAddrOfObjCClass(ClassDecl *theClass,
ForDefinition_t forDefinition) {
assert(ObjCInterop && "getting address of ObjC class in no-interop mode");
LinkEntity entity = LinkEntity::forObjCClass(theClass);
DebugTypeInfo DbgTy(theClass, ObjCClassPtrTy,
getPointerSize(), getPointerAlignment());
auto addr = getAddrOfLLVMVariable(entity, getPointerAlignment(),
forDefinition, ObjCClassStructTy, DbgTy);
return addr;
}
/// Fetch a global reference to the given Objective-C metaclass.
/// The result is always a GlobalValue of ObjCClassPtrTy.
llvm::Constant *IRGenModule::getAddrOfObjCMetaclass(ClassDecl *theClass,
ForDefinition_t forDefinition) {
assert(ObjCInterop && "getting address of ObjC metaclass in no-interop mode");
LinkEntity entity = LinkEntity::forObjCMetaclass(theClass);
DebugTypeInfo DbgTy(theClass, ObjCClassPtrTy,
getPointerSize(), getPointerAlignment());
auto addr = getAddrOfLLVMVariable(entity, getPointerAlignment(),
forDefinition, ObjCClassStructTy, DbgTy);
return addr;
}
/// Fetch the declaration of the metaclass stub for the given class type.
/// The result is always a GlobalValue of ObjCClassPtrTy.
llvm::Constant *IRGenModule::getAddrOfSwiftMetaclassStub(ClassDecl *theClass,
ForDefinition_t forDefinition) {
assert(ObjCInterop && "getting address of metaclass stub in no-interop mode");
LinkEntity entity = LinkEntity::forSwiftMetaclassStub(theClass);
DebugTypeInfo DbgTy(theClass, ObjCClassPtrTy,
getPointerSize(), getPointerAlignment());
auto addr = getAddrOfLLVMVariable(entity, getPointerAlignment(),
forDefinition, ObjCClassStructTy, DbgTy);
return addr;
}
/// Fetch the declaration of a metaclass object. This performs either
/// getAddrOfSwiftMetaclassStub or getAddrOfObjCMetaclass, depending
/// on whether the class is published as an ObjC class.
llvm::Constant *IRGenModule::getAddrOfMetaclassObject(ClassDecl *decl,
ForDefinition_t forDefinition) {
assert((!decl->isGenericContext() || decl->hasClangNode())
&& "generic classes do not have a static metaclass object");
if (decl->checkObjCAncestry() != ObjCClassKind::NonObjC ||
decl->hasClangNode()) {
return getAddrOfObjCMetaclass(decl, forDefinition);
} else {
return getAddrOfSwiftMetaclassStub(decl, forDefinition);
}
}
/// Fetch the type metadata access function for a non-generic type.
llvm::Function *
IRGenModule::getAddrOfTypeMetadataAccessFunction(CanType type,
ForDefinition_t forDefinition) {
assert(!type->hasArchetype() && !type->hasTypeParameter());
LinkEntity entity = LinkEntity::forTypeMetadataAccessFunction(type);
llvm::Function *&entry = GlobalFuncs[entity];
if (entry) {
if (forDefinition) updateLinkageForDefinition(*this, entry, entity);
return entry;
}
auto fnType = llvm::FunctionType::get(TypeMetadataPtrTy, false);
LinkInfo link = LinkInfo::get(*this, entity, forDefinition);
entry = link.createFunction(*this, fnType, DefaultCC, llvm::AttributeSet());
return entry;
}
/// Fetch the type metadata access function for the given generic type.
llvm::Function *
IRGenModule::getAddrOfGenericTypeMetadataAccessFunction(
NominalTypeDecl *nominal,
ArrayRef<llvm::Type *> genericArgs,
ForDefinition_t forDefinition) {
assert(!genericArgs.empty());
assert(nominal->isGenericContext());
auto type = nominal->getDeclaredType()->getCanonicalType();
assert(isa<UnboundGenericType>(type));
LinkEntity entity = LinkEntity::forTypeMetadataAccessFunction(type);
llvm::Function *&entry = GlobalFuncs[entity];
if (entry) {
if (forDefinition) updateLinkageForDefinition(*this, entry, entity);
return entry;
}
auto fnType = llvm::FunctionType::get(TypeMetadataPtrTy, genericArgs, false);
LinkInfo link = LinkInfo::get(*this, entity, forDefinition);
entry = link.createFunction(*this, fnType, DefaultCC, llvm::AttributeSet());
return entry;
}
/// Get or create a type metadata cache variable. These are an
/// implementation detail of type metadata access functions.
llvm::Constant *
IRGenModule::getAddrOfTypeMetadataLazyCacheVariable(CanType type,
ForDefinition_t forDefinition) {
assert(!type->hasArchetype() && !type->hasTypeParameter());
LinkEntity entity = LinkEntity::forTypeMetadataLazyCacheVariable(type);
return getAddrOfLLVMVariable(entity, getPointerAlignment(), forDefinition,
TypeMetadataPtrTy, DebugTypeInfo());
}
/// Define the metadata for a type.
///
/// Some type metadata has information before the address point that the
/// public symbol for the metadata references. This function will rewrite any
/// existing external declaration to the address point as an alias into the
/// full metadata object.
llvm::GlobalValue *IRGenModule::defineTypeMetadata(CanType concreteType,
bool isIndirect,
bool isPattern,
bool isConstant,
llvm::Constant *init,
std::unique_ptr<llvm::GlobalVariable> replace,
llvm::StringRef section) {
assert(init);
assert(!isIndirect && "indirect type metadata not used yet");
/// For concrete metadata, we want to use the initializer on the
/// "full metadata", and define the "direct" address point as an alias.
/// For generic metadata patterns, the address point is always at the
/// beginning of the template (for now...).
TypeMetadataAddress addrKind;
llvm::Type *defaultVarTy;
unsigned adjustmentIndex;
Alignment alignment = getPointerAlignment();
if (isPattern) {
addrKind = TypeMetadataAddress::AddressPoint;
defaultVarTy = TypeMetadataPatternStructTy;
adjustmentIndex = MetadataAdjustmentIndex::None;
} else if (concreteType->getClassOrBoundGenericClass()) {
addrKind = TypeMetadataAddress::FullMetadata;
defaultVarTy = FullHeapMetadataStructTy;
adjustmentIndex = MetadataAdjustmentIndex::Class;
} else {
addrKind = TypeMetadataAddress::FullMetadata;
defaultVarTy = FullTypeMetadataStructTy;
adjustmentIndex = MetadataAdjustmentIndex::ValueType;
}
auto entity = LinkEntity::forTypeMetadata(concreteType, addrKind, isPattern);
auto DbgTy = DebugTypeInfo(MetatypeType::get(concreteType),
defaultVarTy->getPointerTo(),
0, 1, nullptr);
// Define the variable.
llvm::GlobalVariable *var = cast<llvm::GlobalVariable>(
getAddrOfLLVMVariable(entity, alignment, init->getType(), defaultVarTy,
DbgTy));
var->setInitializer(init);
var->setConstant(isConstant);
if (!section.empty())
var->setSection(section);
// Replace the placeholder if we were given one.
if (replace) {
auto replacer = llvm::ConstantExpr::getBitCast(var, replace->getType());
replace->replaceAllUsesWith(replacer);
replace.release();
}
// Keep type metadata around for all types, although the runtime can currently
// only perform name lookup of non-generic types.
addRuntimeResolvableType(concreteType);
// For metadata patterns, we're done.
if (isPattern)
return var;
// For concrete metadata, declare the alias to its address point.
auto directEntity = LinkEntity::forTypeMetadata(concreteType,
TypeMetadataAddress::AddressPoint,
/*isPattern*/ false);
llvm::Constant *addr = var;
// Do an adjustment if necessary.
if (adjustmentIndex) {
llvm::Constant *indices[] = {
llvm::ConstantInt::get(Int32Ty, 0),
llvm::ConstantInt::get(Int32Ty, adjustmentIndex)
};
addr = llvm::ConstantExpr::getInBoundsGetElementPtr(/*Ty=*/nullptr,
addr, indices);
}
addr = llvm::ConstantExpr::getBitCast(addr, TypeMetadataPtrTy);
// Check for an existing forward declaration of the address point.
auto &directEntry = GlobalVars[directEntity];
llvm::GlobalValue *existingVal = nullptr;
if (directEntry) {
existingVal = cast<llvm::GlobalValue>(directEntry);
// Clear the existing value's name so we can steal it.
existingVal->setName("");
}
LinkInfo link = LinkInfo::get(*this, directEntity, ForDefinition);
auto *ptrTy = cast<llvm::PointerType>(addr->getType());
auto *alias = llvm::GlobalAlias::create(
ptrTy->getElementType(), ptrTy->getAddressSpace(), link.getLinkage(),
link.getName(), addr, &Module);
alias->setVisibility(link.getVisibility());
// The full metadata is used based on the visibility of the address point,
// not the metadata itself.
if (link.isUsed()) {
addUsedGlobal(var);
addUsedGlobal(alias);
}
// Replace an existing external declaration for the address point.
if (directEntry) {
auto existingVal = cast<llvm::GlobalValue>(directEntry);
// FIXME: MC breaks when emitting alias references on some platforms
// (rdar://problem/22450593 ). Work around this by referring to the aliasee
// instead.
llvm::Constant *aliasCast = alias->getAliasee();
aliasCast = llvm::ConstantExpr::getBitCast(aliasCast,
directEntry->getType());
existingVal->replaceAllUsesWith(aliasCast);
existingVal->eraseFromParent();
}
directEntry = alias;
return alias;
}
/// Fetch the declaration of the metadata (or metadata template) for a
/// type.
///
/// If the definition type is specified, the result will always be a
/// GlobalValue of the given type, which may not be at the
/// canonical address point for a type metadata.
///
/// If the definition type is not specified, then:
/// - if the metadata is indirect, then the result will not be adjusted
/// and it will have the type pointer-to-T, where T is the type
/// of a direct metadata;
/// - if the metadata is a pattern, then the result will not be
/// adjusted and it will have TypeMetadataPatternPtrTy;
/// - otherwise it will be adjusted to the canonical address point
/// for a type metadata and it will have type TypeMetadataPtrTy.
llvm::Constant *IRGenModule::getAddrOfTypeMetadata(CanType concreteType,
bool isPattern) {
return getAddrOfTypeMetadata(concreteType, isPattern,
SymbolReferenceKind::Absolute).getDirectValue();
}
ConstantReference IRGenModule::getAddrOfTypeMetadata(CanType concreteType,
bool isPattern,
SymbolReferenceKind refKind) {
assert(isPattern || !isa<UnboundGenericType>(concreteType));
llvm::Type *defaultVarTy;
unsigned adjustmentIndex;
Alignment alignment = getPointerAlignment();
ClassDecl *ObjCClass = nullptr;
// Patterns use the pattern type and no adjustment.
if (isPattern) {
defaultVarTy = TypeMetadataPatternStructTy;
adjustmentIndex = 0;
// Objective-C classes use the ObjC class object.
} else if (isa<ClassType>(concreteType) &&
!hasKnownSwiftMetadata(*this,
cast<ClassType>(concreteType)->getDecl())) {
defaultVarTy = TypeMetadataStructTy;
adjustmentIndex = 0;
ObjCClass = cast<ClassType>(concreteType)->getDecl();
// The symbol for other nominal type metadata is generated at the address
// point.
} else if (isa<ClassType>(concreteType) ||
isa<BoundGenericClassType>(concreteType)) {
assert(!concreteType->getClassOrBoundGenericClass()->isForeign()
&& "metadata for foreign classes should be emitted as "
"foreign candidate");
defaultVarTy = TypeMetadataStructTy;
adjustmentIndex = 0;
} else if (concreteType->getAnyNominal()) {
auto nom = concreteType->getNominalOrBoundGenericNominal();
assert((!nom || !nom->hasClangNode())
&& "metadata for foreign type should be emitted as "
"foreign candidate");
(void)nom;
defaultVarTy = TypeMetadataStructTy;
adjustmentIndex = 0;
} else {
// FIXME: Non-nominal metadata provided by the C++ runtime is exported
// with the address of the start of the full metadata object, since
// Clang doesn't provide an easy way to emit symbols aliasing into the
// middle of an object.
defaultVarTy = FullTypeMetadataStructTy;
adjustmentIndex = MetadataAdjustmentIndex::ValueType;
}
// If this is a use, and the type metadata is emitted lazily,
// trigger lazy emission of the metadata.
if (isTypeMetadataEmittedLazily(concreteType)) {
IRGen.addLazyTypeMetadata(concreteType);
}
LinkEntity entity
= ObjCClass ? LinkEntity::forObjCClass(ObjCClass)
: LinkEntity::forTypeMetadata(concreteType,
TypeMetadataAddress::AddressPoint,
isPattern);
auto DbgTy = ObjCClass
? DebugTypeInfo(ObjCClass, ObjCClassPtrTy,
getPointerSize(), getPointerAlignment())
: DebugTypeInfo(MetatypeType::get(concreteType),
defaultVarTy->getPointerTo(),
0, 1, nullptr);
auto addr = getAddrOfLLVMVariable(entity, alignment,
nullptr, defaultVarTy, DbgTy, refKind);
// FIXME: MC breaks when emitting alias references on some platforms
// (rdar://problem/22450593 ). Work around this by referring to the aliasee
// instead.
if (auto alias = dyn_cast<llvm::GlobalAlias>(addr.getValue()))
addr = ConstantReference(alias->getAliasee(), addr.isIndirect());
// Adjust if necessary.
if (adjustmentIndex) {
llvm::Constant *indices[] = {
llvm::ConstantInt::get(Int32Ty, 0),
llvm::ConstantInt::get(Int32Ty, adjustmentIndex)
};
addr = ConstantReference(
llvm::ConstantExpr::getInBoundsGetElementPtr(
/*Ty=*/nullptr, addr.getValue(), indices),
addr.isIndirect());
}
return addr;
}
/// Return the address of a nominal type descriptor. Right now, this
/// must always be for purposes of defining it.
llvm::Constant *IRGenModule::getAddrOfNominalTypeDescriptor(NominalTypeDecl *D,
llvm::Type *definitionType) {
assert(definitionType && "not defining nominal type descriptor?");
auto entity = LinkEntity::forNominalTypeDescriptor(D);
return getAddrOfLLVMVariable(entity, getPointerAlignment(),
definitionType, definitionType,
DebugTypeInfo());
}
llvm::Constant *IRGenModule::getAddrOfProtocolDescriptor(ProtocolDecl *D,
ForDefinition_t forDefinition,
llvm::Type *definitionType) {
if (D->isObjC())
return getAddrOfObjCProtocolRecord(D, forDefinition);
auto entity = LinkEntity::forProtocolDescriptor(D);
return getAddrOfLLVMVariable(entity, getPointerAlignment(), definitionType,
ProtocolDescriptorStructTy, DebugTypeInfo());
}
/// Fetch the declaration of the ivar initializer for the given class.
Optional<llvm::Function*> IRGenModule::getAddrOfIVarInitDestroy(
ClassDecl *cd,
bool isDestroyer,
bool isForeign,
ForDefinition_t forDefinition) {
SILDeclRef silRef(cd,
isDestroyer? SILDeclRef::Kind::IVarDestroyer
: SILDeclRef::Kind::IVarInitializer,
ResilienceExpansion::Minimal,
SILDeclRef::ConstructAtNaturalUncurryLevel,
isForeign);
// Find the SILFunction for the ivar initializer or destroyer.
if (auto silFn = getSILModule().lookUpFunction(silRef)) {
return getAddrOfSILFunction(silFn, forDefinition);
}
return None;
}
/// Returns the address of a value-witness function.
llvm::Function *IRGenModule::getAddrOfValueWitness(CanType abstractType,
ValueWitness index,
ForDefinition_t forDefinition) {
// We shouldn't emit value witness symbols for generic type instances.
assert(!isa<BoundGenericType>(abstractType) &&
"emitting value witness for generic type instance?!");
LinkEntity entity = LinkEntity::forValueWitness(abstractType, index);
llvm::Function *&entry = GlobalFuncs[entity];
if (entry) {
if (forDefinition) updateLinkageForDefinition(*this, entry, entity);
return entry;
}
// Find the appropriate function type.
llvm::FunctionType *fnType =
cast<llvm::FunctionType>(
cast<llvm::PointerType>(getValueWitnessTy(index))
->getElementType());
LinkInfo link = LinkInfo::get(*this, entity, forDefinition);
entry = link.createFunction(*this, fnType, DefaultCC, llvm::AttributeSet());
return entry;
}
/// Returns the address of a value-witness table. If a definition
/// type is provided, the table is created with that type; the return
/// value will be an llvm::GlobalValue. Otherwise, the result will
/// have type WitnessTablePtrTy.
llvm::Constant *IRGenModule::getAddrOfValueWitnessTable(CanType concreteType,
llvm::Type *definitionType) {
LinkEntity entity = LinkEntity::forValueWitnessTable(concreteType);
return getAddrOfLLVMVariable(entity, getPointerAlignment(), definitionType,
WitnessTableTy, DebugTypeInfo());
}
static Address getAddrOfSimpleVariable(IRGenModule &IGM,
llvm::DenseMap<LinkEntity, llvm::Constant*> &cache,
LinkEntity entity,
llvm::Type *type,
Alignment alignment,
ForDefinition_t forDefinition) {
// Check whether it's already cached.
llvm::Constant *&entry = cache[entity];
if (entry) {
auto existing = cast<llvm::GlobalValue>(entry);
assert(alignment == Alignment(existing->getAlignment()));
if (forDefinition) updateLinkageForDefinition(IGM, existing, entity);
return Address(entry, alignment);
}
// Otherwise, we need to create it.
LinkInfo link = LinkInfo::get(IGM, entity, forDefinition);
auto addr = link.createVariable(IGM, type, alignment);
addr->setConstant(true);
entry = addr;
return Address(addr, alignment);
}
/// getAddrOfWitnessTableOffset - Get the address of the global
/// variable which contains an offset within a witness table for the
/// value associated with the given function.
Address IRGenModule::getAddrOfWitnessTableOffset(SILDeclRef code,
ForDefinition_t forDefinition) {
LinkEntity entity =
LinkEntity::forWitnessTableOffset(code.getDecl(),
code.uncurryLevel);
return getAddrOfSimpleVariable(*this, GlobalVars, entity,
SizeTy, getPointerAlignment(),
forDefinition);
}
/// getAddrOfWitnessTableOffset - Get the address of the global
/// variable which contains an offset within a witness table for the
/// value associated with the given member variable..
Address IRGenModule::getAddrOfWitnessTableOffset(VarDecl *field,
ForDefinition_t forDefinition) {
LinkEntity entity =
LinkEntity::forWitnessTableOffset(field, 0);
return ::getAddrOfSimpleVariable(*this, GlobalVars, entity,
SizeTy, getPointerAlignment(),
forDefinition);
}
/// getAddrOfFieldOffset - Get the address of the global variable
/// which contains an offset to apply to either an object (if direct)
/// or a metadata object in order to find an offset to apply to an
/// object (if indirect).
///
/// The result is always a GlobalValue.
Address IRGenModule::getAddrOfFieldOffset(VarDecl *var, bool isIndirect,
ForDefinition_t forDefinition) {
LinkEntity entity = LinkEntity::forFieldOffset(var, isIndirect);
return getAddrOfSimpleVariable(*this, GlobalVars, entity,
SizeTy, getPointerAlignment(),
forDefinition);
}
void IRGenModule::emitNestedTypeDecls(DeclRange members) {
for (Decl *member : members) {
switch (member->getKind()) {
case DeclKind::Import:
case DeclKind::TopLevelCode:
case DeclKind::Protocol:
case DeclKind::Extension:
case DeclKind::InfixOperator:
case DeclKind::PrefixOperator:
case DeclKind::PostfixOperator:
case DeclKind::Param:
case DeclKind::Module:
llvm_unreachable("decl not allowed in type context");
case DeclKind::IfConfig:
continue;
case DeclKind::PatternBinding:
case DeclKind::Var:
case DeclKind::Subscript:
case DeclKind::Func:
case DeclKind::Constructor:
case DeclKind::Destructor:
case DeclKind::EnumCase:
case DeclKind::EnumElement:
// Skip non-type members.
continue;
case DeclKind::AssociatedType:
case DeclKind::GenericTypeParam:
// Do nothing.
continue;
case DeclKind::TypeAlias:
// Do nothing.
continue;
case DeclKind::Enum:
emitEnumDecl(cast<EnumDecl>(member));
continue;
case DeclKind::Struct:
emitStructDecl(cast<StructDecl>(member));
continue;
case DeclKind::Class:
emitClassDecl(cast<ClassDecl>(member));
continue;
}
}
}
static bool shouldEmitCategory(IRGenModule &IGM, ExtensionDecl *ext) {
for (auto conformance : ext->getLocalConformances()) {
if (conformance->getProtocol()->isObjC())
return true;
}
for (auto member : ext->getMembers()) {
if (auto func = dyn_cast<FuncDecl>(member)) {
if (requiresObjCMethodDescriptor(func))
return true;
} else if (auto constructor = dyn_cast<ConstructorDecl>(member)) {
if (requiresObjCMethodDescriptor(constructor))
return true;
} else if (auto var = dyn_cast<VarDecl>(member)) {
if (requiresObjCPropertyDescriptor(IGM, var))
return true;
} else if (auto subscript = dyn_cast<SubscriptDecl>(member)) {
if (requiresObjCSubscriptDescriptor(IGM, subscript))
return true;
}
}
return false;
}
void IRGenModule::emitExtension(ExtensionDecl *ext) {
emitAssociatedTypeMetadataRecord(ext);
emitNestedTypeDecls(ext->getMembers());
// Generate a category if the extension either introduces a
// conformance to an ObjC protocol or introduces a method
// that requires an Objective-C entry point.
ClassDecl *origClass = ext->getExtendedType()->getClassOrBoundGenericClass();
if (!origClass)
return;
if (shouldEmitCategory(*this, ext)) {
assert(origClass && !origClass->isForeign() &&
"CF types cannot have categories emitted");
llvm::Constant *category = emitCategoryData(*this, ext);
category = llvm::ConstantExpr::getBitCast(category, Int8PtrTy);
ObjCCategories.push_back(category);
ObjCCategoryDecls.push_back(ext);
}
}
/// Create an allocation on the stack.
Address IRGenFunction::createAlloca(llvm::Type *type,
Alignment alignment,
const llvm::Twine &name) {
llvm::AllocaInst *alloca = new llvm::AllocaInst(type, name, AllocaIP);
alloca->setAlignment(alignment.getValue());
return Address(alloca, alignment);
}
/// Allocate a fixed-size buffer on the stack.
Address IRGenFunction::createFixedSizeBufferAlloca(const llvm::Twine &name) {
return createAlloca(IGM.getFixedBufferTy(),
getFixedBufferAlignment(IGM),
name);
}
/// Get or create a global string constant.
///
/// \returns an i8* with a null terminator; note that embedded nulls
/// are okay
///
/// FIXME: willBeRelativelyAddressed is only needed to work around an ld64 bug
/// resolving relative references to coalesceable symbols.
/// It should be removed when fixed. rdar://problem/22674524
llvm::Constant *IRGenModule::getAddrOfGlobalString(StringRef data,
bool willBeRelativelyAddressed) {
// Check whether this string already exists.
auto &entry = GlobalStrings[data];
if (entry.second) {
// FIXME: Clear unnamed_addr if the global will be relative referenced
// to work around an ld64 bug. rdar://problem/22674524
if (willBeRelativelyAddressed)
entry.first->setUnnamedAddr(false);
return entry.second;
}
entry = createStringConstant(data, willBeRelativelyAddressed);
return entry.second;
}
/// Get or create a global UTF-16 string constant.
///
/// \returns an i16* with a null terminator; note that embedded nulls
/// are okay
llvm::Constant *IRGenModule::getAddrOfGlobalUTF16String(StringRef utf8) {
// Check whether this string already exists.
auto &entry = GlobalUTF16Strings[utf8];
if (entry) return entry;
// If not, first transcode it to UTF16.
SmallVector<UTF16, 128> buffer(utf8.size() + 1); // +1 for ending nulls.
const UTF8 *fromPtr = (const UTF8 *) utf8.data();
UTF16 *toPtr = &buffer[0];
(void) ConvertUTF8toUTF16(&fromPtr, fromPtr + utf8.size(),
&toPtr, toPtr + utf8.size(),
strictConversion);
// The length of the transcoded string in UTF-8 code points.
size_t utf16Length = toPtr - &buffer[0];
// Null-terminate the UTF-16 string.
*toPtr = 0;
ArrayRef<UTF16> utf16(&buffer[0], utf16Length + 1);
auto init = llvm::ConstantDataArray::get(LLVMContext, utf16);
auto global = new llvm::GlobalVariable(Module, init->getType(), true,
llvm::GlobalValue::PrivateLinkage,
init);
global->setUnnamedAddr(true);
// Drill down to make an i16*.
auto zero = llvm::ConstantInt::get(SizeTy, 0);
llvm::Constant *indices[] = { zero, zero };
auto address = llvm::ConstantExpr::getInBoundsGetElementPtr(
global->getValueType(), global, indices);
// Cache and return.
entry = address;
return address;
}
/// Mangle the name of a type.
StringRef IRGenModule::mangleType(CanType type, SmallVectorImpl<char> &buffer) {
LinkEntity::forTypeMangling(type).mangle(buffer);
return StringRef(buffer.data(), buffer.size());
}
/// Do we have to use resilient access patterns when working with this
/// declaration?
///
/// IRGen is primarily concerned with resilient handling of the following:
/// - For structs, a struct's size might change
/// - For enums, new cases can be added
/// - For classes, the superclass might change the size or number
/// of stored properties
bool IRGenModule::isResilient(NominalTypeDecl *D, ResilienceExpansion expansion) {
return !D->hasFixedLayout(getSwiftModule(), expansion);
}
// The most general resilience expansion where the given declaration is visible.
ResilienceExpansion
IRGenModule::getResilienceExpansionForAccess(NominalTypeDecl *decl) {
if (decl->getModuleContext() == getSwiftModule() &&
decl->getEffectiveAccess() != Accessibility::Public)
return ResilienceExpansion::Maximal;
return ResilienceExpansion::Minimal;
}
// The most general resilience expansion which has knowledge of the declaration's
// layout. Calling isResilient() with this scope will always return false.
ResilienceExpansion
IRGenModule::getResilienceExpansionForLayout(NominalTypeDecl *decl) {
if (isResilient(decl, ResilienceExpansion::Minimal))
return ResilienceExpansion::Maximal;
return getResilienceExpansionForAccess(decl);
}
// The most general resilience expansion which has knowledge of the global
// variable's layout.
ResilienceExpansion
IRGenModule::getResilienceExpansionForLayout(SILGlobalVariable *global) {
if (hasPublicVisibility(global->getLinkage()))
return ResilienceExpansion::Minimal;
return ResilienceExpansion::Maximal;
}
llvm::Constant *IRGenModule::
getAddrOfGenericWitnessTableCache(const NormalProtocolConformance *conf,
ForDefinition_t forDefinition) {
auto entity = LinkEntity::forGenericProtocolWitnessTableCache(conf);
auto expectedTy = getGenericWitnessTableCacheTy();
auto storageTy = (forDefinition ? expectedTy : nullptr);
return getAddrOfLLVMVariable(entity, getPointerAlignment(), storageTy,
expectedTy, DebugTypeInfo());
}
llvm::Function *
IRGenModule::getAddrOfGenericWitnessTableInstantiationFunction(
const NormalProtocolConformance *conf) {
auto forDefinition = ForDefinition;
LinkEntity entity =
LinkEntity::forGenericProtocolWitnessTableInstantiationFunction(conf);
llvm::Function *&entry = GlobalFuncs[entity];
if (entry) {
if (forDefinition) updateLinkageForDefinition(*this, entry, entity);
return entry;
}
auto fnType = llvm::FunctionType::get(VoidTy,
{ WitnessTablePtrTy,
TypeMetadataPtrTy,
Int8PtrPtrTy },
/*varargs*/ false);
LinkInfo link = LinkInfo::get(*this, entity, forDefinition);
entry = link.createFunction(*this, fnType, DefaultCC, llvm::AttributeSet());
return entry;
}
llvm::StructType *IRGenModule::getGenericWitnessTableCacheTy() {
if (auto ty = GenericWitnessTableCacheTy) return ty;
GenericWitnessTableCacheTy = llvm::StructType::create(getLLVMContext(),
{
// WitnessTableSizeInWords
Int16Ty,
// WitnessTablePrivateSizeInWords
Int16Ty,
// Protocol
RelativeAddressTy,
// Pattern
RelativeAddressTy,
// Instantiator
RelativeAddressTy,
// PrivateData
llvm::ArrayType::get(Int8PtrTy, swift::NumGenericMetadataPrivateDataWords)
}, "swift.generic_witness_table_cache");
return GenericWitnessTableCacheTy;
}
/// Fetch the witness table access function for a protocol conformance.
llvm::Function *
IRGenModule::getAddrOfWitnessTableAccessFunction(
const NormalProtocolConformance *conf,
ForDefinition_t forDefinition) {
LinkEntity entity = LinkEntity::forProtocolWitnessTableAccessFunction(conf);
llvm::Function *&entry = GlobalFuncs[entity];
if (entry) {
if (forDefinition) updateLinkageForDefinition(*this, entry, entity);
return entry;
}
llvm::FunctionType *fnType;
if (conf->getDeclContext()->isGenericContext()) {
fnType = llvm::FunctionType::get(WitnessTablePtrTy, {TypeMetadataPtrTy},
false);
} else {
fnType = llvm::FunctionType::get(WitnessTablePtrTy, false);
}
LinkInfo link = LinkInfo::get(*this, entity, forDefinition);
entry = link.createFunction(*this, fnType, DefaultCC, llvm::AttributeSet());
return entry;
}
/// Fetch the lazy witness table access function for a protocol conformance.
llvm::Function *
IRGenModule::getAddrOfWitnessTableLazyAccessFunction(
const NormalProtocolConformance *conf,
CanType conformingType,
ForDefinition_t forDefinition) {
LinkEntity entity =
LinkEntity::forProtocolWitnessTableLazyAccessFunction(conf, conformingType);
llvm::Function *&entry = GlobalFuncs[entity];
if (entry) {
if (forDefinition) updateLinkageForDefinition(*this, entry, entity);
return entry;
}
llvm::FunctionType *fnType
= llvm::FunctionType::get(WitnessTablePtrTy, false);
LinkInfo link = LinkInfo::get(*this, entity, forDefinition);
entry = link.createFunction(*this, fnType, DefaultCC, llvm::AttributeSet());
return entry;
}
/// Get or create a witness table cache variable. These are an
/// implementation detail of witness table lazy access functions.
llvm::Constant *
IRGenModule::getAddrOfWitnessTableLazyCacheVariable(
const NormalProtocolConformance *conf,
CanType conformingType,
ForDefinition_t forDefinition) {
assert(!conformingType->hasArchetype());
LinkEntity entity =
LinkEntity::forProtocolWitnessTableLazyCacheVariable(conf, conformingType);
return getAddrOfLLVMVariable(entity, getPointerAlignment(),
forDefinition, WitnessTablePtrTy,
DebugTypeInfo());
}
/// Look up the address of a witness table.
///
/// TODO: This needs to take a flag for the access mode of the witness table,
/// which may be direct, lazy, or a runtime instantiation template.
/// TODO: Use name from witness table here to lookup witness table instead of
/// recomputing it.
llvm::Constant*
IRGenModule::getAddrOfWitnessTable(const NormalProtocolConformance *conf,
llvm::Type *storageTy) {
auto entity = LinkEntity::forDirectProtocolWitnessTable(conf);
return getAddrOfLLVMVariable(entity, getPointerAlignment(), storageTy,
WitnessTableTy, DebugTypeInfo());
}
llvm::Function *
IRGenModule::getAddrOfAssociatedTypeMetadataAccessFunction(
const NormalProtocolConformance *conformance,
AssociatedTypeDecl *associate) {
auto forDefinition = ForDefinition;
LinkEntity entity =
LinkEntity::forAssociatedTypeMetadataAccessFunction(conformance, associate);
llvm::Function *&entry = GlobalFuncs[entity];
if (entry) {
if (forDefinition) updateLinkageForDefinition(*this, entry, entity);
return entry;
}
auto fnType = getAssociatedTypeMetadataAccessFunctionTy();
LinkInfo link = LinkInfo::get(*this, entity, forDefinition);
entry = link.createFunction(*this, fnType, DefaultCC, llvm::AttributeSet());
return entry;
}
llvm::Function *
IRGenModule::getAddrOfAssociatedTypeWitnessTableAccessFunction(
const NormalProtocolConformance *conformance,
AssociatedTypeDecl *associate,
ProtocolDecl *associateProtocol) {
auto forDefinition = ForDefinition;
assert(conformance->getProtocol() == associate->getProtocol());
LinkEntity entity =
LinkEntity::forAssociatedTypeWitnessTableAccessFunction(conformance,
associate,
associateProtocol);
llvm::Function *&entry = GlobalFuncs[entity];
if (entry) {
if (forDefinition) updateLinkageForDefinition(*this, entry, entity);
return entry;
}
auto fnType = getAssociatedTypeWitnessTableAccessFunctionTy();
LinkInfo link = LinkInfo::get(*this, entity, forDefinition);
entry = link.createFunction(*this, fnType, DefaultCC, llvm::AttributeSet());
return entry;
}
/// Should we be defining the given helper function?
static llvm::Function *shouldDefineHelper(IRGenModule &IGM,
llvm::Constant *fn) {
llvm::Function *def = dyn_cast<llvm::Function>(fn);
if (!def) return nullptr;
if (!def->empty()) return nullptr;
def->setLinkage(llvm::Function::LinkOnceODRLinkage);
def->setVisibility(llvm::Function::HiddenVisibility);
def->setDoesNotThrow();
def->setCallingConv(IGM.DefaultCC);
return def;
}
/// Get or create a helper function with the given name and type, lazily
/// using the given generation function to fill in its body.
///
/// The helper function will be shared between translation units within the
/// current linkage unit, so choose the name carefully to ensure that it
/// does not collide with any other helper function. In general, it should
/// be a Swift-specific C reserved name; that is, it should start with
// "__swift".
llvm::Constant *
IRGenModule::getOrCreateHelperFunction(StringRef fnName, llvm::Type *resultTy,
ArrayRef<llvm::Type*> paramTys,
llvm::function_ref<void(IRGenFunction &IGF)> generate) {
llvm::FunctionType *fnTy =
llvm::FunctionType::get(resultTy, paramTys, false);
llvm::Constant *fn = Module.getOrInsertFunction(fnName, fnTy);
if (llvm::Function *def = shouldDefineHelper(*this, fn)) {
IRGenFunction IGF(*this, def);
if (DebugInfo)
DebugInfo->emitArtificialFunction(IGF, def);
generate(IGF);
}
return fn;
}
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