//===--- CodeGenTypes.h - Type translation for LLVM CodeGen -----*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This is the code that handles AST -> LLVM type lowering.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CLANG_LIB_CODEGEN_CODEGENTYPES_H
#define LLVM_CLANG_LIB_CODEGEN_CODEGENTYPES_H
#include "CGCall.h"
#include "clang/Basic/ABI.h"
#include "clang/CodeGen/CGFunctionInfo.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/IR/Module.h"
namespace llvm {
class FunctionType;
class DataLayout;
class Type;
class LLVMContext;
class StructType;
}
namespace clang {
class ASTContext;
template <typename> class CanQual;
class CXXConstructorDecl;
class CXXMethodDecl;
class CodeGenOptions;
class FunctionProtoType;
class QualType;
class RecordDecl;
class TagDecl;
class TargetInfo;
class Type;
typedef CanQual<Type> CanQualType;
class GlobalDecl;
namespace CodeGen {
class ABIInfo;
class CGCXXABI;
class CGRecordLayout;
class CodeGenModule;
class RequiredArgs;
/// This class organizes the cross-module state that is used while lowering
/// AST types to LLVM types.
class CodeGenTypes {
CodeGenModule &CGM;
// Some of this stuff should probably be left on the CGM.
ASTContext &Context;
llvm::Module &TheModule;
const TargetInfo &Target;
/// The opaque type map for Objective-C interfaces. All direct
/// manipulation is done by the runtime interfaces, which are
/// responsible for coercing to the appropriate type; these opaque
/// types are never refined.
llvm::DenseMap<const ObjCInterfaceType*, llvm::Type *> InterfaceTypes;
/// Maps clang struct type with corresponding record layout info.
llvm::DenseMap<const Type*, std::unique_ptr<CGRecordLayout>> CGRecordLayouts;
/// Contains the LLVM IR type for any converted RecordDecl.
llvm::DenseMap<const Type*, llvm::StructType *> RecordDeclTypes;
/// Hold memoized CGFunctionInfo results.
llvm::FoldingSet<CGFunctionInfo> FunctionInfos{FunctionInfosLog2InitSize};
llvm::SmallPtrSet<const CGFunctionInfo*, 4> FunctionsBeingProcessed;
/// True if we didn't layout a function due to a being inside
/// a recursive struct conversion, set this to true.
bool SkippedLayout;
/// True if any instance of long double types are used.
bool LongDoubleReferenced;
/// This map keeps cache of llvm::Types and maps clang::Type to
/// corresponding llvm::Type.
llvm::DenseMap<const Type *, llvm::Type *> TypeCache;
llvm::DenseMap<const Type *, llvm::Type *> RecordsWithOpaqueMemberPointers;
static constexpr unsigned FunctionInfosLog2InitSize = 9;
/// Helper for ConvertType.
llvm::Type *ConvertFunctionTypeInternal(QualType FT);
public:
CodeGenTypes(CodeGenModule &cgm);
~CodeGenTypes();
const llvm::DataLayout &getDataLayout() const {
return TheModule.getDataLayout();
}
CodeGenModule &getCGM() const { return CGM; }
ASTContext &getContext() const { return Context; }
const TargetInfo &getTarget() const { return Target; }
CGCXXABI &getCXXABI() const;
llvm::LLVMContext &getLLVMContext() { return TheModule.getContext(); }
const CodeGenOptions &getCodeGenOpts() const;
/// Convert clang calling convention to LLVM callilng convention.
unsigned ClangCallConvToLLVMCallConv(CallingConv CC);
/// Derives the 'this' type for codegen purposes, i.e. ignoring method CVR
/// qualification.
CanQualType DeriveThisType(const CXXRecordDecl *RD, const CXXMethodDecl *MD);
/// ConvertType - Convert type T into a llvm::Type.
llvm::Type *ConvertType(QualType T);
/// ConvertTypeForMem - Convert type T into a llvm::Type. This differs from
/// ConvertType in that it is used to convert to the memory representation for
/// a type. For example, the scalar representation for _Bool is i1, but the
/// memory representation is usually i8 or i32, depending on the target.
llvm::Type *ConvertTypeForMem(QualType T);
/// Check whether the given type needs to be laid out in memory
/// using an opaque byte-array type because its load/store type
/// does not have the correct alloc size in the LLVM data layout.
/// If this is false, the load/store type (convertTypeForLoadStore)
/// and memory representation type (ConvertTypeForMem) will
/// be the same type.
bool typeRequiresSplitIntoByteArray(QualType ASTTy,
llvm::Type *LLVMTy = nullptr);
/// Given that T is a scalar type, return the IR type that should
/// be used for load and store operations. For example, this might
/// be i8 for _Bool or i96 for _BitInt(65). The store size of the
/// load/store type (as reported by LLVM's data layout) is always
/// the same as the alloc size of the memory representation type
/// returned by ConvertTypeForMem.
///
/// As an optimization, if you already know the scalar value type
/// for T (as would be returned by ConvertType), you can pass
/// it as the second argument so that it does not need to be
/// recomputed in common cases where the value type and
/// load/store type are the same.
llvm::Type *convertTypeForLoadStore(QualType T, llvm::Type *LLVMTy = nullptr);
/// GetFunctionType - Get the LLVM function type for \arg Info.
llvm::FunctionType *GetFunctionType(const CGFunctionInfo &Info);
llvm::FunctionType *GetFunctionType(GlobalDecl GD);
/// isFuncTypeConvertible - Utility to check whether a function type can
/// be converted to an LLVM type (i.e. doesn't depend on an incomplete tag
/// type).
bool isFuncTypeConvertible(const FunctionType *FT);
bool isFuncParamTypeConvertible(QualType Ty);
/// Determine if a C++ inheriting constructor should have parameters matching
/// those of its inherited constructor.
bool inheritingCtorHasParams(const InheritedConstructor &Inherited,
CXXCtorType Type);
/// GetFunctionTypeForVTable - Get the LLVM function type for use in a vtable,
/// given a CXXMethodDecl. If the method to has an incomplete return type,
/// and/or incomplete argument types, this will return the opaque type.
llvm::Type *GetFunctionTypeForVTable(GlobalDecl GD);
const CGRecordLayout &getCGRecordLayout(const RecordDecl*);
/// UpdateCompletedType - When we find the full definition for a TagDecl,
/// replace the 'opaque' type we previously made for it if applicable.
void UpdateCompletedType(const TagDecl *TD);
/// Remove stale types from the type cache when an inheritance model
/// gets assigned to a class.
void RefreshTypeCacheForClass(const CXXRecordDecl *RD);
// The arrangement methods are split into three families:
// - those meant to drive the signature and prologue/epilogue
// of a function declaration or definition,
// - those meant for the computation of the LLVM type for an abstract
// appearance of a function, and
// - those meant for performing the IR-generation of a call.
// They differ mainly in how they deal with optional (i.e. variadic)
// arguments, as well as unprototyped functions.
//
// Key points:
// - The CGFunctionInfo for emitting a specific call site must include
// entries for the optional arguments.
// - The function type used at the call site must reflect the formal
// signature of the declaration being called, or else the call will
// go awry.
// - For the most part, unprototyped functions are called by casting to
// a formal signature inferred from the specific argument types used
// at the call-site. However, some targets (e.g. x86-64) screw with
// this for compatibility reasons.
const CGFunctionInfo &arrangeGlobalDeclaration(GlobalDecl GD);
/// Given a function info for a declaration, return the function info
/// for a call with the given arguments.
///
/// Often this will be able to simply return the declaration info.
const CGFunctionInfo &arrangeCall(const CGFunctionInfo &declFI,
const CallArgList &args);
/// Free functions are functions that are compatible with an ordinary
/// C function pointer type.
const CGFunctionInfo &arrangeFunctionDeclaration(const FunctionDecl *FD);
const CGFunctionInfo &arrangeFreeFunctionCall(const CallArgList &Args,
const FunctionType *Ty,
bool ChainCall);
const CGFunctionInfo &arrangeFreeFunctionType(CanQual<FunctionProtoType> Ty);
const CGFunctionInfo &arrangeFreeFunctionType(CanQual<FunctionNoProtoType> Ty);
/// A nullary function is a freestanding function of type 'void ()'.
/// This method works for both calls and declarations.
const CGFunctionInfo &arrangeNullaryFunction();
/// A builtin function is a freestanding function using the default
/// C conventions.
const CGFunctionInfo &
arrangeBuiltinFunctionDeclaration(QualType resultType,
const FunctionArgList &args);
const CGFunctionInfo &
arrangeBuiltinFunctionDeclaration(CanQualType resultType,
ArrayRef<CanQualType> argTypes);
const CGFunctionInfo &arrangeBuiltinFunctionCall(QualType resultType,
const CallArgList &args);
/// Objective-C methods are C functions with some implicit parameters.
const CGFunctionInfo &arrangeObjCMethodDeclaration(const ObjCMethodDecl *MD);
const CGFunctionInfo &arrangeObjCMessageSendSignature(const ObjCMethodDecl *MD,
QualType receiverType);
const CGFunctionInfo &arrangeUnprototypedObjCMessageSend(
QualType returnType,
const CallArgList &args);
/// Block invocation functions are C functions with an implicit parameter.
const CGFunctionInfo &arrangeBlockFunctionDeclaration(
const FunctionProtoType *type,
const FunctionArgList &args);
const CGFunctionInfo &arrangeBlockFunctionCall(const CallArgList &args,
const FunctionType *type);
/// C++ methods have some special rules and also have implicit parameters.
const CGFunctionInfo &arrangeCXXMethodDeclaration(const CXXMethodDecl *MD);
const CGFunctionInfo &arrangeCXXStructorDeclaration(GlobalDecl GD);
const CGFunctionInfo &arrangeCXXConstructorCall(const CallArgList &Args,
const CXXConstructorDecl *D,
CXXCtorType CtorKind,
unsigned ExtraPrefixArgs,
unsigned ExtraSuffixArgs,
bool PassProtoArgs = true);
const CGFunctionInfo &arrangeCXXMethodCall(const CallArgList &args,
const FunctionProtoType *type,
RequiredArgs required,
unsigned numPrefixArgs);
const CGFunctionInfo &
arrangeUnprototypedMustTailThunk(const CXXMethodDecl *MD);
const CGFunctionInfo &arrangeMSCtorClosure(const CXXConstructorDecl *CD,
CXXCtorType CT);
const CGFunctionInfo &arrangeCXXMethodType(const CXXRecordDecl *RD,
const FunctionProtoType *FTP,
const CXXMethodDecl *MD);
/// "Arrange" the LLVM information for a call or type with the given
/// signature. This is largely an internal method; other clients
/// should use one of the above routines, which ultimately defer to
/// this.
///
/// \param argTypes - must all actually be canonical as params
const CGFunctionInfo &arrangeLLVMFunctionInfo(
CanQualType returnType, FnInfoOpts opts, ArrayRef<CanQualType> argTypes,
FunctionType::ExtInfo info,
ArrayRef<FunctionProtoType::ExtParameterInfo> paramInfos,
RequiredArgs args);
/// Compute a new LLVM record layout object for the given record.
std::unique_ptr<CGRecordLayout> ComputeRecordLayout(const RecordDecl *D,
llvm::StructType *Ty);
/// addRecordTypeName - Compute a name from the given record decl with an
/// optional suffix and name the given LLVM type using it.
void addRecordTypeName(const RecordDecl *RD, llvm::StructType *Ty,
StringRef suffix);
public: // These are internal details of CGT that shouldn't be used externally.
/// ConvertRecordDeclType - Lay out a tagged decl type like struct or union.
llvm::StructType *ConvertRecordDeclType(const RecordDecl *TD);
/// getExpandedTypes - Expand the type \arg Ty into the LLVM
/// argument types it would be passed as. See ABIArgInfo::Expand.
void getExpandedTypes(QualType Ty,
SmallVectorImpl<llvm::Type *>::iterator &TI);
/// IsZeroInitializable - Return whether a type can be
/// zero-initialized (in the C++ sense) with an LLVM zeroinitializer.
bool isZeroInitializable(QualType T);
/// Check if the pointer type can be zero-initialized (in the C++ sense)
/// with an LLVM zeroinitializer.
bool isPointerZeroInitializable(QualType T);
/// IsZeroInitializable - Return whether a record type can be
/// zero-initialized (in the C++ sense) with an LLVM zeroinitializer.
bool isZeroInitializable(const RecordDecl *RD);
bool isLongDoubleReferenced() const { return LongDoubleReferenced; }
bool isRecordLayoutComplete(const Type *Ty) const;
unsigned getTargetAddressSpace(QualType T) const;
};
} // end namespace CodeGen
} // end namespace clang
#endif