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swift-mirror/lib/IRGen/GenDecl.cpp
swiftix 2573782c8b Merge pull request #1357 from swiftix/wip-runtime-calling-convention 
Prepare the ground for using a new calling convention for functions from the runtime library
2016-03-01 16:22:37 -08:00

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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 "CallingConvention.h"
#include "Explosion.h"
#include "FixedTypeInfo.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 = tryEmitConstantTypeMetadataRef(IGM, origTy);
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 = SILMod->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 : *SILMod) {
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 IRGenModuleDispatcher::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->SILMod->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->SILMod->getSILGlobals()) {
Decl *decl = v.getDecl();
CurrentIGMPtr IGM = getGenModule(decl ? decl->getDeclContext() : nullptr);
IGM->emitSILGlobalVariable(&v);
}
PrimaryIGM->emitCoverageMapping();
// Emit SIL functions.
bool isWholeModule = PrimaryIGM->SILMod->isWholeModule();
for (SILFunction &f : *PrimaryIGM->SILMod) {
// 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->emitSILStaticInitializer();
}
// Emit witness tables.
for (SILWitnessTable &wt : PrimaryIGM->SILMod->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,
SILMod->getSwiftModule(),
SourceLoc(),
ImportKind::Module, SourceLoc(),
AccessPath);
DebugInfo->emitImport(Imp);
}
// Emit external definitions used by this module.
for (auto def : Context.ExternalDefinitions) {
emitExternalDefinition(def);
}
// Let ClangCodeGen emit its global data structures (llvm.used, debug info,
// etc.)
finalizeClangCodeGen();
}
void IRGenModule::addNominalTypeDecl(const NominalTypeDecl *Decl) {
NominalTypeDecls.push_back(Decl);
}
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 IRGenModuleDispatcher::emitProtocolConformances() {
for (auto &m : *this) {
m.second->emitProtocolConformances();
}
}
void IRGenModuleDispatcher::emitTypeMetadataRecords() {
for (auto &m : *this) {
m.second->emitTypeMetadataRecords();
}
}
void IRGenModuleDispatcher::emitFieldTypeMetadataRecords() {
for (auto &m : *this) {
m.second->emitFieldTypeMetadataRecords();
}
}
void IRGenModuleDispatcher::emitAssociatedTypeMetadataRecords() {
for (auto &m : *this) {
m.second->emitAssociatedTypeMetadataRecords();
}
}
/// Emit any lazy definitions (of globals or functions or whatever
/// else) that we require.
void IRGenModuleDispatcher::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->SILMod->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 = SILMod->zombies_begin(); I != SILMod->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 : Opts.VerifyTypeLayoutNames) {
// Look up the name in the module.
SmallVector<ValueDecl*, 1> lookup;
swift::Module *M = SILMod->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 = SILMod->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.SILMod->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::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");
}
bool LinkEntity::isAvailableExternally(IRGenModule &IGM) const {
// FIXME: Removing this triggers a linker bug
if (getKind() == Kind::ObjCClass ||
getKind() == Kind::ObjCMetaclass)
return true;
// This is a conservative estimate. For now, we say if the decl was defined
// in the same TU (not just the same module), it is not external.
if (isDeclKind(getKind())) {
auto *DC = getDecl()->getDeclContext()->getModuleScopeContext();
if (isa<ClangModuleUnit>(DC) ||
DC == IGM.SILMod->getAssociatedContext())
return false;
}
if (!hasPublicVisibility(getLinkage(IGM, NotForDefinition)))
return false;
return true;
}
bool LinkEntity::isFragile(IRGenModule &IGM) const {
switch (getKind()) {
case Kind::SILFunction:
return getSILFunction()->isFragile();
case Kind::SILGlobalVariable:
return getSILGlobalVariable()->isFragile();
case Kind::DirectProtocolWitnessTable: {
if (auto wt = IGM.SILMod->lookUpWitnessTable(getProtocolConformance())) {
return wt->isFragile();
} else {
return false;
}
}
default:
break;
}
return false;
}
static std::pair<llvm::GlobalValue::LinkageTypes,
llvm::GlobalValue::VisibilityTypes>
getIRLinkage(IRGenModule &IGM,
SILLinkage linkage, bool isFragile, 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;
}
if (isFragile) {
// Fragile functions/globals must be visible from outside, regardless of
// their accessibility. If a caller is also fragile and inlined into another
// module it must be able to access this (not-inlined) function/global.
switch (linkage) {
case SILLinkage::Hidden:
case SILLinkage::Private:
linkage = SILLinkage::Public;
break;
case SILLinkage::Public:
case SILLinkage::Shared:
case SILLinkage::HiddenExternal:
case SILLinkage::PrivateExternal:
case SILLinkage::PublicExternal:
case SILLinkage::SharedExternal:
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.dispatcher.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: {
auto visibility = isFragile ? llvm::GlobalValue::DefaultVisibility
: llvm::GlobalValue::HiddenVisibility;
if (isDefinition) {
return {llvm::GlobalValue::AvailableExternallyLinkage, visibility};
}
return {llvm::GlobalValue::ExternalLinkage, visibility};
}
}
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),
entity.isFragile(IGM),
ForDefinition,
entity.isWeakImported(IGM.SILMod->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),
entity.isFragile(IGM),
isDefinition,
entity.isWeakImported(IGM.SILMod->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 DebugType,
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 && ForDefinition)
IGM.DebugInfo->
emitGlobalVariableDeclaration(var,
DebugName.empty() ? getName() : DebugName,
getName(), DebugType, 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())
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 = dispatcher.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(), SILMod->isWholeModule()))
dispatcher.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);
}
}
/// 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 debugType) {
// 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, debugType);
// 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.
std::pair<llvm::Constant *, IRGenModule::DirectOrGOT>
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, DirectOrGOT::Direct};
}
auto &gotEntry = GlobalGOTEquivalents[entity];
if (gotEntry) {
return {gotEntry, DirectOrGOT::GOT};
}
// 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, DirectOrGOT::GOT};
}
/// If true, we lazily initialize metadata at runtime because the layout
/// is only partially known. Otherwise, we can emit a direct reference a
/// constant metadata symbol.
bool
IRGenModule::hasMetadataPattern(NominalTypeDecl *theDecl) {
assert(theDecl != nullptr);
// Protocols must be special-cased in a few places.
assert(!isa<ProtocolDecl>(theDecl));
// For classes, we already computed this when we did the layout.
// FIXME: Try not to call this for classes of other modules, by referencing
// the metadata accessor instead.
if (auto *theClass = dyn_cast<ClassDecl>(theDecl))
return irgen::getClassHasMetadataPattern(*this, theClass);
// Ok, we have a value type. If it is generic, it is always initialized
// at runtime.
if (theDecl->isGenericContext())
return true;
// If the type is not fixed-size, its size depends on resilient types,
// and the metadata is initialized at runtime.
if (!getTypeInfoForUnlowered(theDecl->getDeclaredType()).isFixedSize())
return true;
return false;
}
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();
if (IGM.hasMetadataPattern(nom)) {
// Conformances for generics, concrete subclasses of generics, and
// resiliently-sized types are represented by referencing the
// nominal type descriptor.
typeKind = TypeMetadataRecordKind::UniqueNominalTypeDescriptor;
entity = LinkEntity::forNominalTypeDescriptor(nom);
defaultTy = IGM.NominalTypeDescriptorTy;
defaultPtrTy = IGM.NominalTypeDescriptorPtrTy;
} else if (auto ct = dyn_cast<ClassType>(conformingType)) {
auto clas = ct->getDecl();
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(std::pair<llvm::Constant *,
IRGenModule::DirectOrGOT> target,
llvm::Constant *base,
ArrayRef<unsigned> baseIndices) {
llvm::Constant *relativeAddr =
emitDirectRelativeReference(target.first, base, baseIndices);
// If the reference is to a GOT entry, 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.second == IRGenModule::DirectOrGOT::GOT) {
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.
std::pair<llvm::Constant*, DirectOrGOT> witnessTableRef;
auto witnessTableVar = getAddrOfWitnessTable(conformance);
witnessTableRef = std::make_pair(witnessTableVar,
DirectOrGOT::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 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()
&& "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());
assert(!type->hasUnboundGenericType());
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) {
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)) {
dispatcher.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);
// 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))
addr = alias->getAliasee();
// Adjust 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);
}
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 = SILMod->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);
DebugTypeInfo DbgTy(concreteType, WitnessTablePtrTy,
getPointerSize(), getPointerAlignment(),
nullptr);
return getAddrOfLLVMVariable(entity, getPointerAlignment(), definitionType,
WitnessTableTy, DbgTy);
}
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) {
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(SILMod->getSwiftModule(), expansion);
}
// The most general resilience expansion where the given declaration is visible.
ResilienceExpansion
IRGenModule::getResilienceExpansionForAccess(NominalTypeDecl *decl) {
if (decl->getModuleContext() == SILMod->getSwiftModule() &&
decl->getFormalAccess() != 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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