//===--- 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;

  CGCXXABI &TheCXXABI;

  // This should not be moved earlier, since its initialization depends on some

  // of the previous reference members being already initialized

  const ABIInfo &TheABIInfo;

  /// 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};

  /// This set keeps track of records that we're currently converting

  /// to an IR type.  For example, when converting:

  /// struct A { struct B { int x; } } when processing 'x', the 'A' and 'B'

  /// types will be in this set.

  llvm::SmallPtrSet<const Type*, 4> RecordsBeingLaidOut;

  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;

  SmallVector<const RecordDecl *, 8> DeferredRecords;

  /// 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();

  }

  ASTContext &getContext() const { return Context; }

  const ABIInfo &getABIInfo() const { return TheABIInfo; }

  const TargetInfo &getTarget() const { return Target; }

  CGCXXABI &getCXXABI() const { return TheCXXABI; }

  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, bool ForBitField = false);

  /// 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,

                                                bool instanceMethod,

                                                bool chainCall,

                                                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 isRecordLayoutComplete(const Type *Ty) const;

  bool noRecordsBeingLaidOut() const {

    return RecordsBeingLaidOut.empty();

  }

  bool isRecordBeingLaidOut(const Type *Ty) const {

    return RecordsBeingLaidOut.count(Ty);

  }

};

}  // end namespace CodeGen

}  // end namespace clang

#endif