1 //===- RecordLayout.cpp - Layout information for a struct/union -----------===//
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 //  This file defines the RecordLayout interface.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "clang/AST/RecordLayout.h"
14 #include "clang/AST/ASTContext.h"
15 #include "clang/Basic/TargetCXXABI.h"
16 #include "clang/Basic/TargetInfo.h"
17 #include <cassert>
18 
19 using namespace clang;
20 
21 void ASTRecordLayout::Destroy(ASTContext &Ctx) {
22   if (CXXInfo) {
23     CXXInfo->~CXXRecordLayoutInfo();
24     Ctx.Deallocate(CXXInfo);
25   }
26   this->~ASTRecordLayout();
27   Ctx.Deallocate(this);
28 }
29 
30 ASTRecordLayout::ASTRecordLayout(const ASTContext &Ctx, CharUnits size,
31                                  CharUnits alignment,
32                                  CharUnits preferredAlignment,
33                                  CharUnits unadjustedAlignment,
34                                  CharUnits requiredAlignment,
35                                  CharUnits datasize,
36                                  ArrayRef<uint64_t> fieldoffsets)
37     : Size(size), DataSize(datasize), Alignment(alignment),
38       PreferredAlignment(preferredAlignment),
39       UnadjustedAlignment(unadjustedAlignment),
40       RequiredAlignment(requiredAlignment) {
41   FieldOffsets.append(Ctx, fieldoffsets.begin(), fieldoffsets.end());
42 }
43 
44 // Constructor for C++ records.
45 ASTRecordLayout::ASTRecordLayout(
46     const ASTContext &Ctx, CharUnits size, CharUnits alignment,
47     CharUnits preferredAlignment, CharUnits unadjustedAlignment,
48     CharUnits requiredAlignment, bool hasOwnVFPtr, bool hasExtendableVFPtr,
49     CharUnits vbptroffset, CharUnits datasize, ArrayRef<uint64_t> fieldoffsets,
50     CharUnits nonvirtualsize, CharUnits nonvirtualalignment,
51     CharUnits preferrednvalignment, CharUnits SizeOfLargestEmptySubobject,
52     const CXXRecordDecl *PrimaryBase, bool IsPrimaryBaseVirtual,
53     const CXXRecordDecl *BaseSharingVBPtr, bool EndsWithZeroSizedObject,
54     bool LeadsWithZeroSizedBase, const BaseOffsetsMapTy &BaseOffsets,
55     const VBaseOffsetsMapTy &VBaseOffsets)
56     : Size(size), DataSize(datasize), Alignment(alignment),
57       PreferredAlignment(preferredAlignment),
58       UnadjustedAlignment(unadjustedAlignment),
59       RequiredAlignment(requiredAlignment),
60       CXXInfo(new (Ctx) CXXRecordLayoutInfo) {
61   FieldOffsets.append(Ctx, fieldoffsets.begin(), fieldoffsets.end());
62 
63   CXXInfo->PrimaryBase.setPointer(PrimaryBase);
64   CXXInfo->PrimaryBase.setInt(IsPrimaryBaseVirtual);
65   CXXInfo->NonVirtualSize = nonvirtualsize;
66   CXXInfo->NonVirtualAlignment = nonvirtualalignment;
67   CXXInfo->PreferredNVAlignment = preferrednvalignment;
68   CXXInfo->SizeOfLargestEmptySubobject = SizeOfLargestEmptySubobject;
69   CXXInfo->BaseOffsets = BaseOffsets;
70   CXXInfo->VBaseOffsets = VBaseOffsets;
71   CXXInfo->HasOwnVFPtr = hasOwnVFPtr;
72   CXXInfo->VBPtrOffset = vbptroffset;
73   CXXInfo->HasExtendableVFPtr = hasExtendableVFPtr;
74   CXXInfo->BaseSharingVBPtr = BaseSharingVBPtr;
75   CXXInfo->EndsWithZeroSizedObject = EndsWithZeroSizedObject;
76   CXXInfo->LeadsWithZeroSizedBase = LeadsWithZeroSizedBase;
77 
78 #ifndef NDEBUG
79     if (const CXXRecordDecl *PrimaryBase = getPrimaryBase()) {
80       if (isPrimaryBaseVirtual()) {
81         if (Ctx.getTargetInfo().getCXXABI().hasPrimaryVBases()) {
82           assert(getVBaseClassOffset(PrimaryBase).isZero() &&
83                  "Primary virtual base must be at offset 0!");
84         }
85       } else {
86         assert(getBaseClassOffset(PrimaryBase).isZero() &&
87                "Primary base must be at offset 0!");
88       }
89     }
90 #endif
91 }
92