1 //===--- LayoutOverrideSource.h --Override Record Layouts -------*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #ifndef LLVM_CLANG_FRONTEND_LAYOUTOVERRIDESOURCE_H 10 #define LLVM_CLANG_FRONTEND_LAYOUTOVERRIDESOURCE_H 11 12 #include "clang/AST/ExternalASTSource.h" 13 #include "clang/Basic/LLVM.h" 14 #include "llvm/ADT/StringMap.h" 15 #include "llvm/ADT/StringRef.h" 16 17 namespace clang { 18 /// An external AST source that overrides the layout of 19 /// a specified set of record types. 20 /// 21 /// This class is used only for testing the ability of external AST sources 22 /// to override the layout of record types. Its input is the output format 23 /// of the command-line argument -fdump-record-layouts. 24 class LayoutOverrideSource : public ExternalASTSource { 25 /// The layout of a given record. 26 struct Layout { 27 /// The size of the record. 28 uint64_t Size; 29 30 /// The alignment of the record. 31 uint64_t Align; 32 33 /// The offsets of non-virtual base classes in the record. 34 SmallVector<CharUnits, 8> BaseOffsets; 35 36 /// The offsets of virtual base classes in the record. 37 SmallVector<CharUnits, 8> VBaseOffsets; 38 39 /// The offsets of the fields, in source order. 40 SmallVector<uint64_t, 8> FieldOffsets; 41 }; 42 43 /// The set of layouts that will be overridden. 44 llvm::StringMap<Layout> Layouts; 45 46 public: 47 /// Create a new AST source that overrides the layout of some 48 /// set of record types. 49 /// 50 /// The file is the result of passing -fdump-record-layouts to a file. 51 explicit LayoutOverrideSource(StringRef Filename); 52 53 /// If this particular record type has an overridden layout, 54 /// return that layout. 55 bool 56 layoutRecordType(const RecordDecl *Record, 57 uint64_t &Size, uint64_t &Alignment, 58 llvm::DenseMap<const FieldDecl *, uint64_t> &FieldOffsets, 59 llvm::DenseMap<const CXXRecordDecl *, CharUnits> &BaseOffsets, 60 llvm::DenseMap<const CXXRecordDecl *, 61 CharUnits> &VirtualBaseOffsets) override; 62 63 /// Dump the overridden layouts. 64 void dump(); 65 }; 66 } 67 68 #endif 69