1 //===- RecordLayout.cpp - Layout information for a struct/union -----------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 //  This file defines the RecordLayout interface.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "clang/AST/RecordLayout.h"
15 #include "clang/AST/ASTContext.h"
16 #include "clang/Basic/TargetCXXABI.h"
17 #include "clang/Basic/TargetInfo.h"
18 #include <cassert>
19 
20 using namespace clang;
21 
22 void ASTRecordLayout::Destroy(ASTContext &Ctx) {
23   if (CXXInfo) {
24     CXXInfo->~CXXRecordLayoutInfo();
25     Ctx.Deallocate(CXXInfo);
26   }
27   this->~ASTRecordLayout();
28   Ctx.Deallocate(this);
29 }
30 
31 ASTRecordLayout::ASTRecordLayout(const ASTContext &Ctx, CharUnits size,
32                                  CharUnits alignment,
33                                  CharUnits requiredAlignment,
34                                  CharUnits datasize,
35                                  ArrayRef<uint64_t> fieldoffsets)
36     : Size(size), DataSize(datasize), Alignment(alignment),
37       RequiredAlignment(requiredAlignment) {
38   FieldOffsets.append(Ctx, fieldoffsets.begin(), fieldoffsets.end());
39 }
40 
41 // Constructor for C++ records.
42 ASTRecordLayout::ASTRecordLayout(const ASTContext &Ctx,
43                                  CharUnits size, CharUnits alignment,
44                                  CharUnits requiredAlignment,
45                                  bool hasOwnVFPtr, bool hasExtendableVFPtr,
46                                  CharUnits vbptroffset,
47                                  CharUnits datasize,
48                                  ArrayRef<uint64_t> fieldoffsets,
49                                  CharUnits nonvirtualsize,
50                                  CharUnits nonvirtualalignment,
51                                  CharUnits SizeOfLargestEmptySubobject,
52                                  const CXXRecordDecl *PrimaryBase,
53                                  bool IsPrimaryBaseVirtual,
54                                  const CXXRecordDecl *BaseSharingVBPtr,
55                                  bool EndsWithZeroSizedObject,
56                                  bool LeadsWithZeroSizedBase,
57                                  const BaseOffsetsMapTy& BaseOffsets,
58                                  const VBaseOffsetsMapTy& VBaseOffsets)
59   : Size(size), DataSize(datasize), Alignment(alignment),
60     RequiredAlignment(requiredAlignment), CXXInfo(new (Ctx) CXXRecordLayoutInfo)
61 {
62   FieldOffsets.append(Ctx, fieldoffsets.begin(), fieldoffsets.end());
63 
64   CXXInfo->PrimaryBase.setPointer(PrimaryBase);
65   CXXInfo->PrimaryBase.setInt(IsPrimaryBaseVirtual);
66   CXXInfo->NonVirtualSize = nonvirtualsize;
67   CXXInfo->NonVirtualAlignment = nonvirtualalignment;
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