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
17namespace 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