include/clang/AST/RecordLayout.h - third_party/swift-clang - Git at Google

 //===--- RecordLayout.h - Layout information for a struct/union -*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 //  This file defines the RecordLayout interface.
 //
 //===----------------------------------------------------------------------===//

 #ifndef LLVM_CLANG_AST_RECORDLAYOUT_H
 #define LLVM_CLANG_AST_RECORDLAYOUT_H

 #include "clang/AST/CharUnits.h"
 #include "clang/AST/DeclCXX.h"
 #include "llvm/ADT/DenseMap.h"

 namespace clang {
   class ASTContext;
   class FieldDecl;
   class RecordDecl;
   class CXXRecordDecl;

 /// ASTRecordLayout -
 /// This class contains layout information for one RecordDecl,
 /// which is a struct/union/class.  The decl represented must be a definition,
 /// not a forward declaration.
 /// This class is also used to contain layout information for one
 /// ObjCInterfaceDecl. FIXME - Find appropriate name.
 /// These objects are managed by ASTContext.
 class ASTRecordLayout {
 public:
   struct VBaseInfo {
     /// The offset to this virtual base in the complete-object layout
     /// of this class.
     CharUnits VBaseOffset;

   private:
     /// Whether this virtual base requires a vtordisp field in the
     /// Microsoft ABI.  These fields are required for certain operations
     /// in constructors and destructors.
     bool HasVtorDisp;

   public:
     bool hasVtorDisp() const { return HasVtorDisp; }

     VBaseInfo() : HasVtorDisp(false) {}

     VBaseInfo(CharUnits VBaseOffset, bool hasVtorDisp) :
      VBaseOffset(VBaseOffset), HasVtorDisp(hasVtorDisp) {}
   };

   typedef llvm::DenseMap<const CXXRecordDecl *, VBaseInfo>
     VBaseOffsetsMapTy;

 private:
   /// Size - Size of record in characters.
   CharUnits Size;

   /// DataSize - Size of record in characters without tail padding.
   CharUnits DataSize;

   // Alignment - Alignment of record in characters.
   CharUnits Alignment;

   /// RequiredAlignment - The required alignment of the object.  In the MS-ABI
   /// the __declspec(align()) trumps #pramga pack and must always be obeyed.
   CharUnits RequiredAlignment;

   /// FieldOffsets - Array of field offsets in bits.
   ASTVector<uint64_t> FieldOffsets;

   /// CXXRecordLayoutInfo - Contains C++ specific layout information.
   struct CXXRecordLayoutInfo {
     /// NonVirtualSize - The non-virtual size (in chars) of an object, which is
     /// the size of the object without virtual bases.
     CharUnits NonVirtualSize;

     /// NonVirtualAlignment - The non-virtual alignment (in chars) of an object,
     /// which is the alignment of the object without virtual bases.
     CharUnits NonVirtualAlignment;

     /// SizeOfLargestEmptySubobject - The size of the largest empty subobject
     /// (either a base or a member). Will be zero if the class doesn't contain
     /// any empty subobjects.
     CharUnits SizeOfLargestEmptySubobject;

     /// VBPtrOffset - Virtual base table offset (Microsoft-only).
     CharUnits VBPtrOffset;

     /// HasOwnVFPtr - Does this class provide a virtual function table
     /// (vtable in Itanium, vftbl in Microsoft) that is independent from
     /// its base classes?
     bool HasOwnVFPtr : 1;

     /// HasVFPtr - Does this class have a vftable that could be extended by
     /// a derived class.  The class may have inherited this pointer from
     /// a primary base class.
     bool HasExtendableVFPtr : 1;

     /// EndsWithZeroSizedObject - True if this class contains a zero sized
     /// member or base or a base with a zero sized member or base.
     /// Only used for MS-ABI.
     bool EndsWithZeroSizedObject : 1;

     /// \brief True if this class is zero sized or first base is zero sized or
     /// has this property.  Only used for MS-ABI.
     bool LeadsWithZeroSizedBase : 1;

     /// PrimaryBase - The primary base info for this record.
     llvm::PointerIntPair<const CXXRecordDecl *, 1, bool> PrimaryBase;

     /// BaseSharingVBPtr - The base we share vbptr with.
     const CXXRecordDecl *BaseSharingVBPtr;

     /// FIXME: This should really use a SmallPtrMap, once we have one in LLVM :)
     typedef llvm::DenseMap<const CXXRecordDecl *, CharUnits> BaseOffsetsMapTy;

     /// BaseOffsets - Contains a map from base classes to their offset.
     BaseOffsetsMapTy BaseOffsets;

     /// VBaseOffsets - Contains a map from vbase classes to their offset.
     VBaseOffsetsMapTy VBaseOffsets;
   };

   /// CXXInfo - If the record layout is for a C++ record, this will have
   /// C++ specific information about the record.
   CXXRecordLayoutInfo *CXXInfo;

   friend class ASTContext;

   ASTRecordLayout(const ASTContext &Ctx, CharUnits size, CharUnits alignment,
                   CharUnits requiredAlignment, CharUnits datasize,
                   ArrayRef<uint64_t> fieldoffsets);

   // Constructor for C++ records.
   typedef CXXRecordLayoutInfo::BaseOffsetsMapTy BaseOffsetsMapTy;
   ASTRecordLayout(const ASTContext &Ctx,
                   CharUnits size, CharUnits alignment,
                   CharUnits requiredAlignment,
                   bool hasOwnVFPtr, bool hasExtendableVFPtr,
                   CharUnits vbptroffset,
                   CharUnits datasize,
                   ArrayRef<uint64_t> fieldoffsets,
                   CharUnits nonvirtualsize, CharUnits nonvirtualalignment,
                   CharUnits SizeOfLargestEmptySubobject,
                   const CXXRecordDecl *PrimaryBase,
                   bool IsPrimaryBaseVirtual,
                   const CXXRecordDecl *BaseSharingVBPtr,
                   bool EndsWithZeroSizedObject,
                   bool LeadsWithZeroSizedBase,
                   const BaseOffsetsMapTy& BaseOffsets,
                   const VBaseOffsetsMapTy& VBaseOffsets);

   ~ASTRecordLayout() = default;

   void Destroy(ASTContext &Ctx);

   ASTRecordLayout(const ASTRecordLayout &) = delete;
   void operator=(const ASTRecordLayout &) = delete;
 public:

   /// getAlignment - Get the record alignment in characters.
   CharUnits getAlignment() const { return Alignment; }

   /// getSize - Get the record size in characters.
   CharUnits getSize() const { return Size; }

   /// getFieldCount - Get the number of fields in the layout.
   unsigned getFieldCount() const { return FieldOffsets.size(); }

   /// getFieldOffset - Get the offset of the given field index, in
   /// bits.
   uint64_t getFieldOffset(unsigned FieldNo) const {
     return FieldOffsets[FieldNo];
   }

   /// getDataSize() - Get the record data size, which is the record size
   /// without tail padding, in characters.
   CharUnits getDataSize() const {
     return DataSize;
   }

   /// getNonVirtualSize - Get the non-virtual size (in chars) of an object,
   /// which is the size of the object without virtual bases.
   CharUnits getNonVirtualSize() const {
     assert(CXXInfo && "Record layout does not have C++ specific info!");

     return CXXInfo->NonVirtualSize;
   }

   /// getNonVirtualSize - Get the non-virtual alignment (in chars) of an object,
   /// which is the alignment of the object without virtual bases.
   CharUnits getNonVirtualAlignment() const {
     assert(CXXInfo && "Record layout does not have C++ specific info!");

     return CXXInfo->NonVirtualAlignment;
   }

   /// getPrimaryBase - Get the primary base for this record.
   const CXXRecordDecl *getPrimaryBase() const {
     assert(CXXInfo && "Record layout does not have C++ specific info!");

     return CXXInfo->PrimaryBase.getPointer();
   }

   /// isPrimaryBaseVirtual - Get whether the primary base for this record
   /// is virtual or not.
   bool isPrimaryBaseVirtual() const {
     assert(CXXInfo && "Record layout does not have C++ specific info!");

     return CXXInfo->PrimaryBase.getInt();
   }

   /// getBaseClassOffset - Get the offset, in chars, for the given base class.
   CharUnits getBaseClassOffset(const CXXRecordDecl *Base) const {
     assert(CXXInfo && "Record layout does not have C++ specific info!");
     assert(CXXInfo->BaseOffsets.count(Base) && "Did not find base!");

     return CXXInfo->BaseOffsets[Base];
   }

   /// getVBaseClassOffset - Get the offset, in chars, for the given base class.
   CharUnits getVBaseClassOffset(const CXXRecordDecl *VBase) const {
     assert(CXXInfo && "Record layout does not have C++ specific info!");
     assert(CXXInfo->VBaseOffsets.count(VBase) && "Did not find base!");

     return CXXInfo->VBaseOffsets[VBase].VBaseOffset;
   }

   CharUnits getSizeOfLargestEmptySubobject() const {
     assert(CXXInfo && "Record layout does not have C++ specific info!");
     return CXXInfo->SizeOfLargestEmptySubobject;
   }

   /// hasOwnVFPtr - Does this class provide its own virtual-function
   /// table pointer, rather than inheriting one from a primary base
   /// class?  If so, it is at offset zero.
   ///
   /// This implies that the ABI has no primary base class, meaning
   /// that it has no base classes that are suitable under the conditions
   /// of the ABI.
   bool hasOwnVFPtr() const {
     assert(CXXInfo && "Record layout does not have C++ specific info!");
     return CXXInfo->HasOwnVFPtr;
   }

   /// hasVFPtr - Does this class have a virtual function table pointer
   /// that can be extended by a derived class?  This is synonymous with
   /// this class having a VFPtr at offset zero.
   bool hasExtendableVFPtr() const {
     assert(CXXInfo && "Record layout does not have C++ specific info!");
     return CXXInfo->HasExtendableVFPtr;
   }

   /// hasOwnVBPtr - Does this class provide its own virtual-base
   /// table pointer, rather than inheriting one from a primary base
   /// class?
   ///
   /// This implies that the ABI has no primary base class, meaning
   /// that it has no base classes that are suitable under the conditions
   /// of the ABI.
   bool hasOwnVBPtr() const {
     assert(CXXInfo && "Record layout does not have C++ specific info!");
     return hasVBPtr() && !CXXInfo->BaseSharingVBPtr;
   }

   /// hasVBPtr - Does this class have a virtual function table pointer.
   bool hasVBPtr() const {
     assert(CXXInfo && "Record layout does not have C++ specific info!");
     return !CXXInfo->VBPtrOffset.isNegative();
   }

   CharUnits getRequiredAlignment() const {
     return RequiredAlignment;
   }

   bool endsWithZeroSizedObject() const {
     return CXXInfo && CXXInfo->EndsWithZeroSizedObject;
   }

   bool leadsWithZeroSizedBase() const {
     assert(CXXInfo && "Record layout does not have C++ specific info!");
     return CXXInfo->LeadsWithZeroSizedBase;
   }

   /// getVBPtrOffset - Get the offset for virtual base table pointer.
   /// This is only meaningful with the Microsoft ABI.
   CharUnits getVBPtrOffset() const {
     assert(CXXInfo && "Record layout does not have C++ specific info!");
     return CXXInfo->VBPtrOffset;
   }

   const CXXRecordDecl *getBaseSharingVBPtr() const {
     assert(CXXInfo && "Record layout does not have C++ specific info!");
     return CXXInfo->BaseSharingVBPtr;
   }

   const VBaseOffsetsMapTy &getVBaseOffsetsMap() const {
     assert(CXXInfo && "Record layout does not have C++ specific info!");
     return CXXInfo->VBaseOffsets;
   }
 };

 }  // end namespace clang

 #endif
	//===--- RecordLayout.h - Layout information for a struct/union -- C++ --===//
	//
	// The LLVM Compiler Infrastructure
	//
	// This file is distributed under the University of Illinois Open Source
	// License. See LICENSE.TXT for details.
	//
	//===----------------------------------------------------------------------===//
	//
	// This file defines the RecordLayout interface.
	//
	//===----------------------------------------------------------------------===//

	#ifndef LLVM_CLANG_AST_RECORDLAYOUT_H
	#define LLVM_CLANG_AST_RECORDLAYOUT_H

	#include "clang/AST/CharUnits.h"
	#include "clang/AST/DeclCXX.h"
	#include "llvm/ADT/DenseMap.h"

	namespace clang {
	class ASTContext;
	class FieldDecl;
	class RecordDecl;
	class CXXRecordDecl;

	/// ASTRecordLayout -
	/// This class contains layout information for one RecordDecl,
	/// which is a struct/union/class. The decl represented must be a definition,
	/// not a forward declaration.
	/// This class is also used to contain layout information for one
	/// ObjCInterfaceDecl. FIXME - Find appropriate name.
	/// These objects are managed by ASTContext.
	class ASTRecordLayout {
	public:
	struct VBaseInfo {
	/// The offset to this virtual base in the complete-object layout
	/// of this class.
	CharUnits VBaseOffset;

	private:
	/// Whether this virtual base requires a vtordisp field in the
	/// Microsoft ABI. These fields are required for certain operations
	/// in constructors and destructors.
	bool HasVtorDisp;

	public:
	bool hasVtorDisp() const { return HasVtorDisp; }

	VBaseInfo() : HasVtorDisp(false) {}

	VBaseInfo(CharUnits VBaseOffset, bool hasVtorDisp) :
	VBaseOffset(VBaseOffset), HasVtorDisp(hasVtorDisp) {}
	};

	typedef llvm::DenseMap<const CXXRecordDecl *, VBaseInfo>
	VBaseOffsetsMapTy;

	private:
	/// Size - Size of record in characters.
	CharUnits Size;

	/// DataSize - Size of record in characters without tail padding.
	CharUnits DataSize;

	// Alignment - Alignment of record in characters.
	CharUnits Alignment;

	/// RequiredAlignment - The required alignment of the object. In the MS-ABI
	/// the __declspec(align()) trumps #pramga pack and must always be obeyed.
	CharUnits RequiredAlignment;

	/// FieldOffsets - Array of field offsets in bits.
	ASTVector<uint64_t> FieldOffsets;

	/// CXXRecordLayoutInfo - Contains C++ specific layout information.
	struct CXXRecordLayoutInfo {
	/// NonVirtualSize - The non-virtual size (in chars) of an object, which is
	/// the size of the object without virtual bases.
	CharUnits NonVirtualSize;

	/// NonVirtualAlignment - The non-virtual alignment (in chars) of an object,
	/// which is the alignment of the object without virtual bases.
	CharUnits NonVirtualAlignment;

	/// SizeOfLargestEmptySubobject - The size of the largest empty subobject
	/// (either a base or a member). Will be zero if the class doesn't contain
	/// any empty subobjects.
	CharUnits SizeOfLargestEmptySubobject;

	/// VBPtrOffset - Virtual base table offset (Microsoft-only).
	CharUnits VBPtrOffset;

	/// HasOwnVFPtr - Does this class provide a virtual function table
	/// (vtable in Itanium, vftbl in Microsoft) that is independent from
	/// its base classes?
	bool HasOwnVFPtr : 1;

	/// HasVFPtr - Does this class have a vftable that could be extended by
	/// a derived class. The class may have inherited this pointer from
	/// a primary base class.
	bool HasExtendableVFPtr : 1;

	/// EndsWithZeroSizedObject - True if this class contains a zero sized
	/// member or base or a base with a zero sized member or base.
	/// Only used for MS-ABI.
	bool EndsWithZeroSizedObject : 1;

	/// \brief True if this class is zero sized or first base is zero sized or
	/// has this property. Only used for MS-ABI.
	bool LeadsWithZeroSizedBase : 1;

	/// PrimaryBase - The primary base info for this record.
	llvm::PointerIntPair<const CXXRecordDecl *, 1, bool> PrimaryBase;

	/// BaseSharingVBPtr - The base we share vbptr with.
	const CXXRecordDecl *BaseSharingVBPtr;

	/// FIXME: This should really use a SmallPtrMap, once we have one in LLVM :)
	typedef llvm::DenseMap<const CXXRecordDecl *, CharUnits> BaseOffsetsMapTy;

	/// BaseOffsets - Contains a map from base classes to their offset.
	BaseOffsetsMapTy BaseOffsets;

	/// VBaseOffsets - Contains a map from vbase classes to their offset.
	VBaseOffsetsMapTy VBaseOffsets;
	};

	/// CXXInfo - If the record layout is for a C++ record, this will have
	/// C++ specific information about the record.
	CXXRecordLayoutInfo *CXXInfo;

	friend class ASTContext;

	ASTRecordLayout(const ASTContext &Ctx, CharUnits size, CharUnits alignment,
	CharUnits requiredAlignment, CharUnits datasize,
	ArrayRef<uint64_t> fieldoffsets);

	// Constructor for C++ records.
	typedef CXXRecordLayoutInfo::BaseOffsetsMapTy BaseOffsetsMapTy;
	ASTRecordLayout(const ASTContext &Ctx,
	CharUnits size, CharUnits alignment,
	CharUnits requiredAlignment,
	bool hasOwnVFPtr, bool hasExtendableVFPtr,
	CharUnits vbptroffset,
	CharUnits datasize,
	ArrayRef<uint64_t> fieldoffsets,
	CharUnits nonvirtualsize, CharUnits nonvirtualalignment,
	CharUnits SizeOfLargestEmptySubobject,
	const CXXRecordDecl *PrimaryBase,
	bool IsPrimaryBaseVirtual,
	const CXXRecordDecl *BaseSharingVBPtr,
	bool EndsWithZeroSizedObject,
	bool LeadsWithZeroSizedBase,
	const BaseOffsetsMapTy& BaseOffsets,
	const VBaseOffsetsMapTy& VBaseOffsets);

	~ASTRecordLayout() = default;

	void Destroy(ASTContext &Ctx);

	ASTRecordLayout(const ASTRecordLayout &) = delete;
	void operator=(const ASTRecordLayout &) = delete;
	public:

	/// getAlignment - Get the record alignment in characters.
	CharUnits getAlignment() const { return Alignment; }

	/// getSize - Get the record size in characters.
	CharUnits getSize() const { return Size; }

	/// getFieldCount - Get the number of fields in the layout.
	unsigned getFieldCount() const { return FieldOffsets.size(); }

	/// getFieldOffset - Get the offset of the given field index, in
	/// bits.
	uint64_t getFieldOffset(unsigned FieldNo) const {
	return FieldOffsets[FieldNo];
	}

	/// getDataSize() - Get the record data size, which is the record size
	/// without tail padding, in characters.
	CharUnits getDataSize() const {
	return DataSize;
	}

	/// getNonVirtualSize - Get the non-virtual size (in chars) of an object,
	/// which is the size of the object without virtual bases.
	CharUnits getNonVirtualSize() const {
	assert(CXXInfo && "Record layout does not have C++ specific info!");

	return CXXInfo->NonVirtualSize;
	}

	/// getNonVirtualSize - Get the non-virtual alignment (in chars) of an object,
	/// which is the alignment of the object without virtual bases.
	CharUnits getNonVirtualAlignment() const {
	assert(CXXInfo && "Record layout does not have C++ specific info!");

	return CXXInfo->NonVirtualAlignment;
	}

	/// getPrimaryBase - Get the primary base for this record.
	const CXXRecordDecl *getPrimaryBase() const {
	assert(CXXInfo && "Record layout does not have C++ specific info!");

	return CXXInfo->PrimaryBase.getPointer();
	}

	/// isPrimaryBaseVirtual - Get whether the primary base for this record
	/// is virtual or not.
	bool isPrimaryBaseVirtual() const {
	assert(CXXInfo && "Record layout does not have C++ specific info!");

	return CXXInfo->PrimaryBase.getInt();
	}

	/// getBaseClassOffset - Get the offset, in chars, for the given base class.
	CharUnits getBaseClassOffset(const CXXRecordDecl *Base) const {
	assert(CXXInfo && "Record layout does not have C++ specific info!");
	assert(CXXInfo->BaseOffsets.count(Base) && "Did not find base!");

	return CXXInfo->BaseOffsets[Base];
	}

	/// getVBaseClassOffset - Get the offset, in chars, for the given base class.
	CharUnits getVBaseClassOffset(const CXXRecordDecl *VBase) const {
	assert(CXXInfo && "Record layout does not have C++ specific info!");
	assert(CXXInfo->VBaseOffsets.count(VBase) && "Did not find base!");

	return CXXInfo->VBaseOffsets[VBase].VBaseOffset;
	}

	CharUnits getSizeOfLargestEmptySubobject() const {
	assert(CXXInfo && "Record layout does not have C++ specific info!");
	return CXXInfo->SizeOfLargestEmptySubobject;
	}

	/// hasOwnVFPtr - Does this class provide its own virtual-function
	/// table pointer, rather than inheriting one from a primary base
	/// class? If so, it is at offset zero.
	///
	/// This implies that the ABI has no primary base class, meaning
	/// that it has no base classes that are suitable under the conditions
	/// of the ABI.
	bool hasOwnVFPtr() const {
	assert(CXXInfo && "Record layout does not have C++ specific info!");
	return CXXInfo->HasOwnVFPtr;
	}

	/// hasVFPtr - Does this class have a virtual function table pointer
	/// that can be extended by a derived class? This is synonymous with
	/// this class having a VFPtr at offset zero.
	bool hasExtendableVFPtr() const {
	assert(CXXInfo && "Record layout does not have C++ specific info!");
	return CXXInfo->HasExtendableVFPtr;
	}

	/// hasOwnVBPtr - Does this class provide its own virtual-base
	/// table pointer, rather than inheriting one from a primary base
	/// class?
	///
	/// This implies that the ABI has no primary base class, meaning
	/// that it has no base classes that are suitable under the conditions
	/// of the ABI.
	bool hasOwnVBPtr() const {
	assert(CXXInfo && "Record layout does not have C++ specific info!");
	return hasVBPtr() && !CXXInfo->BaseSharingVBPtr;
	}

	/// hasVBPtr - Does this class have a virtual function table pointer.
	bool hasVBPtr() const {
	assert(CXXInfo && "Record layout does not have C++ specific info!");
	return !CXXInfo->VBPtrOffset.isNegative();
	}

	CharUnits getRequiredAlignment() const {
	return RequiredAlignment;
	}

	bool endsWithZeroSizedObject() const {
	return CXXInfo && CXXInfo->EndsWithZeroSizedObject;
	}

	bool leadsWithZeroSizedBase() const {
	assert(CXXInfo && "Record layout does not have C++ specific info!");
	return CXXInfo->LeadsWithZeroSizedBase;
	}

	/// getVBPtrOffset - Get the offset for virtual base table pointer.
	/// This is only meaningful with the Microsoft ABI.
	CharUnits getVBPtrOffset() const {
	assert(CXXInfo && "Record layout does not have C++ specific info!");
	return CXXInfo->VBPtrOffset;
	}

	const CXXRecordDecl *getBaseSharingVBPtr() const {
	assert(CXXInfo && "Record layout does not have C++ specific info!");
	return CXXInfo->BaseSharingVBPtr;
	}

	const VBaseOffsetsMapTy &getVBaseOffsetsMap() const {
	assert(CXXInfo && "Record layout does not have C++ specific info!");
	return CXXInfo->VBaseOffsets;
	}
	};

	} // end namespace clang

	#endif