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Diffstat (limited to 'gnu/llvm/tools/clang/lib/CodeGen/CGRecordLayout.h')
| -rw-r--r-- | gnu/llvm/tools/clang/lib/CodeGen/CGRecordLayout.h | 220 |
1 files changed, 0 insertions, 220 deletions
diff --git a/gnu/llvm/tools/clang/lib/CodeGen/CGRecordLayout.h b/gnu/llvm/tools/clang/lib/CodeGen/CGRecordLayout.h deleted file mode 100644 index 41084294ab9..00000000000 --- a/gnu/llvm/tools/clang/lib/CodeGen/CGRecordLayout.h +++ /dev/null @@ -1,220 +0,0 @@ -//===--- CGRecordLayout.h - LLVM Record Layout Information ------*- C++ -*-===// -// -// The LLVM Compiler Infrastructure -// -// This file is distributed under the University of Illinois Open Source -// License. See LICENSE.TXT for details. -// -//===----------------------------------------------------------------------===// - -#ifndef LLVM_CLANG_LIB_CODEGEN_CGRECORDLAYOUT_H -#define LLVM_CLANG_LIB_CODEGEN_CGRECORDLAYOUT_H - -#include "clang/AST/CharUnits.h" -#include "clang/AST/DeclCXX.h" -#include "clang/Basic/LLVM.h" -#include "llvm/ADT/DenseMap.h" -#include "llvm/IR/DerivedTypes.h" - -namespace llvm { - class StructType; -} - -namespace clang { -namespace CodeGen { - -/// Structure with information about how a bitfield should be accessed. -/// -/// Often we layout a sequence of bitfields as a contiguous sequence of bits. -/// When the AST record layout does this, we represent it in the LLVM IR's type -/// as either a sequence of i8 members or a byte array to reserve the number of -/// bytes touched without forcing any particular alignment beyond the basic -/// character alignment. -/// -/// Then accessing a particular bitfield involves converting this byte array -/// into a single integer of that size (i24 or i40 -- may not be power-of-two -/// size), loading it, and shifting and masking to extract the particular -/// subsequence of bits which make up that particular bitfield. This structure -/// encodes the information used to construct the extraction code sequences. -/// The CGRecordLayout also has a field index which encodes which byte-sequence -/// this bitfield falls within. Let's assume the following C struct: -/// -/// struct S { -/// char a, b, c; -/// unsigned bits : 3; -/// unsigned more_bits : 4; -/// unsigned still_more_bits : 7; -/// }; -/// -/// This will end up as the following LLVM type. The first array is the -/// bitfield, and the second is the padding out to a 4-byte alignmnet. -/// -/// %t = type { i8, i8, i8, i8, i8, [3 x i8] } -/// -/// When generating code to access more_bits, we'll generate something -/// essentially like this: -/// -/// define i32 @foo(%t* %base) { -/// %0 = gep %t* %base, i32 0, i32 3 -/// %2 = load i8* %1 -/// %3 = lshr i8 %2, 3 -/// %4 = and i8 %3, 15 -/// %5 = zext i8 %4 to i32 -/// ret i32 %i -/// } -/// -struct CGBitFieldInfo { - /// The offset within a contiguous run of bitfields that are represented as - /// a single "field" within the LLVM struct type. This offset is in bits. - unsigned Offset : 16; - - /// The total size of the bit-field, in bits. - unsigned Size : 15; - - /// Whether the bit-field is signed. - unsigned IsSigned : 1; - - /// The storage size in bits which should be used when accessing this - /// bitfield. - unsigned StorageSize; - - /// The offset of the bitfield storage from the start of the struct. - CharUnits StorageOffset; - - CGBitFieldInfo() - : Offset(), Size(), IsSigned(), StorageSize(), StorageOffset() {} - - CGBitFieldInfo(unsigned Offset, unsigned Size, bool IsSigned, - unsigned StorageSize, CharUnits StorageOffset) - : Offset(Offset), Size(Size), IsSigned(IsSigned), - StorageSize(StorageSize), StorageOffset(StorageOffset) {} - - void print(raw_ostream &OS) const; - void dump() const; - - /// Given a bit-field decl, build an appropriate helper object for - /// accessing that field (which is expected to have the given offset and - /// size). - static CGBitFieldInfo MakeInfo(class CodeGenTypes &Types, - const FieldDecl *FD, - uint64_t Offset, uint64_t Size, - uint64_t StorageSize, - CharUnits StorageOffset); -}; - -/// CGRecordLayout - This class handles struct and union layout info while -/// lowering AST types to LLVM types. -/// -/// These layout objects are only created on demand as IR generation requires. -class CGRecordLayout { - friend class CodeGenTypes; - - CGRecordLayout(const CGRecordLayout &) = delete; - void operator=(const CGRecordLayout &) = delete; - -private: - /// The LLVM type corresponding to this record layout; used when - /// laying it out as a complete object. - llvm::StructType *CompleteObjectType; - - /// The LLVM type for the non-virtual part of this record layout; - /// used when laying it out as a base subobject. - llvm::StructType *BaseSubobjectType; - - /// Map from (non-bit-field) struct field to the corresponding llvm struct - /// type field no. This info is populated by record builder. - llvm::DenseMap<const FieldDecl *, unsigned> FieldInfo; - - /// Map from (bit-field) struct field to the corresponding llvm struct type - /// field no. This info is populated by record builder. - llvm::DenseMap<const FieldDecl *, CGBitFieldInfo> BitFields; - - // FIXME: Maybe we could use a CXXBaseSpecifier as the key and use a single - // map for both virtual and non-virtual bases. - llvm::DenseMap<const CXXRecordDecl *, unsigned> NonVirtualBases; - - /// Map from virtual bases to their field index in the complete object. - llvm::DenseMap<const CXXRecordDecl *, unsigned> CompleteObjectVirtualBases; - - /// False if any direct or indirect subobject of this class, when - /// considered as a complete object, requires a non-zero bitpattern - /// when zero-initialized. - bool IsZeroInitializable : 1; - - /// False if any direct or indirect subobject of this class, when - /// considered as a base subobject, requires a non-zero bitpattern - /// when zero-initialized. - bool IsZeroInitializableAsBase : 1; - -public: - CGRecordLayout(llvm::StructType *CompleteObjectType, - llvm::StructType *BaseSubobjectType, - bool IsZeroInitializable, - bool IsZeroInitializableAsBase) - : CompleteObjectType(CompleteObjectType), - BaseSubobjectType(BaseSubobjectType), - IsZeroInitializable(IsZeroInitializable), - IsZeroInitializableAsBase(IsZeroInitializableAsBase) {} - - /// Return the "complete object" LLVM type associated with - /// this record. - llvm::StructType *getLLVMType() const { - return CompleteObjectType; - } - - /// Return the "base subobject" LLVM type associated with - /// this record. - llvm::StructType *getBaseSubobjectLLVMType() const { - return BaseSubobjectType; - } - - /// Check whether this struct can be C++ zero-initialized - /// with a zeroinitializer. - bool isZeroInitializable() const { - return IsZeroInitializable; - } - - /// Check whether this struct can be C++ zero-initialized - /// with a zeroinitializer when considered as a base subobject. - bool isZeroInitializableAsBase() const { - return IsZeroInitializableAsBase; - } - - /// Return llvm::StructType element number that corresponds to the - /// field FD. - unsigned getLLVMFieldNo(const FieldDecl *FD) const { - FD = FD->getCanonicalDecl(); - assert(FieldInfo.count(FD) && "Invalid field for record!"); - return FieldInfo.lookup(FD); - } - - unsigned getNonVirtualBaseLLVMFieldNo(const CXXRecordDecl *RD) const { - assert(NonVirtualBases.count(RD) && "Invalid non-virtual base!"); - return NonVirtualBases.lookup(RD); - } - - /// Return the LLVM field index corresponding to the given - /// virtual base. Only valid when operating on the complete object. - unsigned getVirtualBaseIndex(const CXXRecordDecl *base) const { - assert(CompleteObjectVirtualBases.count(base) && "Invalid virtual base!"); - return CompleteObjectVirtualBases.lookup(base); - } - - /// Return the BitFieldInfo that corresponds to the field FD. - const CGBitFieldInfo &getBitFieldInfo(const FieldDecl *FD) const { - FD = FD->getCanonicalDecl(); - assert(FD->isBitField() && "Invalid call for non-bit-field decl!"); - llvm::DenseMap<const FieldDecl *, CGBitFieldInfo>::const_iterator - it = BitFields.find(FD); - assert(it != BitFields.end() && "Unable to find bitfield info"); - return it->second; - } - - void print(raw_ostream &OS) const; - void dump() const; -}; - -} // end namespace CodeGen -} // end namespace clang - -#endif |