Coverage Report

Created: 2022-07-16 07:03

/Users/buildslave/jenkins/workspace/coverage/llvm-project/clang/lib/AST/ItaniumCXXABI.cpp
Line
Count
Source (jump to first uncovered line)
1
//===------- ItaniumCXXABI.cpp - AST support for the Itanium C++ ABI ------===//
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 provides C++ AST support targeting the Itanium C++ ABI, which is
10
// documented at:
11
//  http://www.codesourcery.com/public/cxx-abi/abi.html
12
//  http://www.codesourcery.com/public/cxx-abi/abi-eh.html
13
//
14
// It also supports the closely-related ARM C++ ABI, documented at:
15
// http://infocenter.arm.com/help/topic/com.arm.doc.ihi0041c/IHI0041C_cppabi.pdf
16
//
17
//===----------------------------------------------------------------------===//
18
19
#include "CXXABI.h"
20
#include "clang/AST/ASTContext.h"
21
#include "clang/AST/DeclCXX.h"
22
#include "clang/AST/Mangle.h"
23
#include "clang/AST/MangleNumberingContext.h"
24
#include "clang/AST/RecordLayout.h"
25
#include "clang/AST/Type.h"
26
#include "clang/Basic/TargetInfo.h"
27
#include "llvm/ADT/FoldingSet.h"
28
#include "llvm/ADT/iterator.h"
29
30
using namespace clang;
31
32
namespace {
33
34
/// According to Itanium C++ ABI 5.1.2:
35
/// the name of an anonymous union is considered to be
36
/// the name of the first named data member found by a pre-order,
37
/// depth-first, declaration-order walk of the data members of
38
/// the anonymous union.
39
/// If there is no such data member (i.e., if all of the data members
40
/// in the union are unnamed), then there is no way for a program to
41
/// refer to the anonymous union, and there is therefore no need to mangle its name.
42
///
43
/// Returns the name of anonymous union VarDecl or nullptr if it is not found.
44
6
static const IdentifierInfo *findAnonymousUnionVarDeclName(const VarDecl& VD) {
45
6
  const RecordType *RT = VD.getType()->getAs<RecordType>();
46
6
  assert(RT && "type of VarDecl is expected to be RecordType.");
47
0
  assert(RT->getDecl()->isUnion() && "RecordType is expected to be a union.");
48
6
  if (const FieldDecl *FD = RT->getDecl()->findFirstNamedDataMember()) {
49
5
    return FD->getIdentifier();
50
5
  }
51
52
1
  return nullptr;
53
6
}
54
55
/// The name of a decomposition declaration.
56
struct DecompositionDeclName {
57
  using BindingArray = ArrayRef<const BindingDecl*>;
58
59
  /// Representative example of a set of bindings with these names.
60
  BindingArray Bindings;
61
62
  /// Iterators over the sequence of identifiers in the name.
63
  struct Iterator
64
      : llvm::iterator_adaptor_base<Iterator, BindingArray::const_iterator,
65
                                    std::random_access_iterator_tag,
66
                                    const IdentifierInfo *> {
67
2
    Iterator(BindingArray::const_iterator It) : iterator_adaptor_base(It) {}
68
1
    const IdentifierInfo *operator*() const {
69
1
      return (*this->I)->getIdentifier();
70
1
    }
71
  };
72
1
  Iterator begin() const { return Iterator(Bindings.begin()); }
73
1
  Iterator end() const { return Iterator(Bindings.end()); }
74
};
75
}
76
77
namespace llvm {
78
144
template<typename T> bool isDenseMapKeyEmpty(T V) {
79
144
  return llvm::DenseMapInfo<T>::isEqual(
80
144
      V, llvm::DenseMapInfo<T>::getEmptyKey());
81
144
}
82
6
template<typename T> bool isDenseMapKeyTombstone(T V) {
83
6
  return llvm::DenseMapInfo<T>::isEqual(
84
6
      V, llvm::DenseMapInfo<T>::getTombstoneKey());
85
6
}
86
87
template<typename T>
88
72
Optional<bool> areDenseMapKeysEqualSpecialValues(T LHS, T RHS) {
89
72
  bool LHSEmpty = isDenseMapKeyEmpty(LHS);
90
72
  bool RHSEmpty = isDenseMapKeyEmpty(RHS);
91
72
  if (LHSEmpty || 
RHSEmpty7
)
92
69
    return LHSEmpty && 
RHSEmpty65
;
93
94
3
  bool LHSTombstone = isDenseMapKeyTombstone(LHS);
95
3
  bool RHSTombstone = isDenseMapKeyTombstone(RHS);
96
3
  if (LHSTombstone || RHSTombstone)
97
3
    return LHSTombstone && 
RHSTombstone0
;
98
99
0
  return None;
100
3
}
101
102
template<>
103
struct DenseMapInfo<DecompositionDeclName> {
104
  using ArrayInfo = llvm::DenseMapInfo<ArrayRef<const BindingDecl*>>;
105
5
  static DecompositionDeclName getEmptyKey() {
106
5
    return {ArrayInfo::getEmptyKey()};
107
5
  }
108
3
  static DecompositionDeclName getTombstoneKey() {
109
3
    return {ArrayInfo::getTombstoneKey()};
110
3
  }
111
1
  static unsigned getHashValue(DecompositionDeclName Key) {
112
1
    assert(!isEqual(Key, getEmptyKey()) && !isEqual(Key, getTombstoneKey()));
113
0
    return llvm::hash_combine_range(Key.begin(), Key.end());
114
1
  }
115
72
  static bool isEqual(DecompositionDeclName LHS, DecompositionDeclName RHS) {
116
72
    if (Optional<bool> Result = areDenseMapKeysEqualSpecialValues(
117
72
            LHS.Bindings, RHS.Bindings))
118
72
      return *Result;
119
120
0
    return LHS.Bindings.size() == RHS.Bindings.size() &&
121
0
           std::equal(LHS.begin(), LHS.end(), RHS.begin());
122
72
  }
123
};
124
}
125
126
namespace {
127
128
/// Keeps track of the mangled names of lambda expressions and block
129
/// literals within a particular context.
130
class ItaniumNumberingContext : public MangleNumberingContext {
131
  ItaniumMangleContext *Mangler;
132
  llvm::StringMap<unsigned> LambdaManglingNumbers;
133
  unsigned BlockManglingNumber = 0;
134
  llvm::DenseMap<const IdentifierInfo *, unsigned> VarManglingNumbers;
135
  llvm::DenseMap<const IdentifierInfo *, unsigned> TagManglingNumbers;
136
  llvm::DenseMap<DecompositionDeclName, unsigned>
137
      DecompsitionDeclManglingNumbers;
138
139
public:
140
37.3k
  ItaniumNumberingContext(ItaniumMangleContext *Mangler) : Mangler(Mangler) {}
141
142
5.17k
  unsigned getManglingNumber(const CXXMethodDecl *CallOperator) override {
143
5.17k
    const CXXRecordDecl *Lambda = CallOperator->getParent();
144
5.17k
    assert(Lambda->isLambda());
145
146
    // Computation of the <lambda-sig> is non-trivial and subtle. Rather than
147
    // duplicating it here, just mangle the <lambda-sig> directly.
148
0
    llvm::SmallString<128> LambdaSig;
149
5.17k
    llvm::raw_svector_ostream Out(LambdaSig);
150
5.17k
    Mangler->mangleLambdaSig(Lambda, Out);
151
152
5.17k
    return ++LambdaManglingNumbers[LambdaSig];
153
5.17k
  }
154
155
307
  unsigned getManglingNumber(const BlockDecl *BD) override {
156
307
    return ++BlockManglingNumber;
157
307
  }
158
159
5.22k
  unsigned getStaticLocalNumber(const VarDecl *VD) override {
160
5.22k
    return 0;
161
5.22k
  }
162
163
  /// Variable decls are numbered by identifier.
164
5.22k
  unsigned getManglingNumber(const VarDecl *VD, unsigned) override {
165
5.22k
    if (auto *DD = dyn_cast<DecompositionDecl>(VD)) {
166
1
      DecompositionDeclName Name{DD->bindings()};
167
1
      return ++DecompsitionDeclManglingNumbers[Name];
168
1
    }
169
170
5.22k
    const IdentifierInfo *Identifier = VD->getIdentifier();
171
5.22k
    if (!Identifier) {
172
      // VarDecl without an identifier represents an anonymous union
173
      // declaration.
174
6
      Identifier = findAnonymousUnionVarDeclName(*VD);
175
6
    }
176
5.22k
    return ++VarManglingNumbers[Identifier];
177
5.22k
  }
178
179
47.4k
  unsigned getManglingNumber(const TagDecl *TD, unsigned) override {
180
47.4k
    return ++TagManglingNumbers[TD->getIdentifier()];
181
47.4k
  }
182
};
183
184
// A version of this for SYCL that makes sure that 'device' mangling context
185
// matches the lambda mangling number, so that __builtin_sycl_unique_stable_name
186
// can be consistently generated between a MS and Itanium host by just referring
187
// to the device mangling number.
188
class ItaniumSYCLNumberingContext : public ItaniumNumberingContext {
189
  llvm::DenseMap<const CXXMethodDecl *, unsigned> ManglingNumbers;
190
  using ManglingItr = decltype(ManglingNumbers)::iterator;
191
192
public:
193
  ItaniumSYCLNumberingContext(ItaniumMangleContext *Mangler)
194
37
      : ItaniumNumberingContext(Mangler) {}
195
196
75
  unsigned getManglingNumber(const CXXMethodDecl *CallOperator) override {
197
75
    unsigned Number = ItaniumNumberingContext::getManglingNumber(CallOperator);
198
75
    std::pair<ManglingItr, bool> emplace_result =
199
75
        ManglingNumbers.try_emplace(CallOperator, Number);
200
75
    (void)emplace_result;
201
75
    assert(emplace_result.second && "Lambda number set multiple times?");
202
0
    return Number;
203
75
  }
204
205
  using ItaniumNumberingContext::getManglingNumber;
206
207
75
  unsigned getDeviceManglingNumber(const CXXMethodDecl *CallOperator) override {
208
75
    ManglingItr Itr = ManglingNumbers.find(CallOperator);
209
75
    assert(Itr != ManglingNumbers.end() && "Lambda not yet mangled?");
210
211
0
    return Itr->second;
212
75
  }
213
};
214
215
class ItaniumCXXABI : public CXXABI {
216
private:
217
  std::unique_ptr<MangleContext> Mangler;
218
protected:
219
  ASTContext &Context;
220
public:
221
  ItaniumCXXABI(ASTContext &Ctx)
222
69.9k
      : Mangler(Ctx.createMangleContext()), Context(Ctx) {}
223
224
  MemberPointerInfo
225
819
  getMemberPointerInfo(const MemberPointerType *MPT) const override {
226
819
    const TargetInfo &Target = Context.getTargetInfo();
227
819
    TargetInfo::IntType PtrDiff = Target.getPtrDiffType(0);
228
819
    MemberPointerInfo MPI;
229
819
    MPI.Width = Target.getTypeWidth(PtrDiff);
230
819
    MPI.Align = Target.getTypeAlign(PtrDiff);
231
819
    MPI.HasPadding = false;
232
819
    if (MPT->isMemberFunctionPointer())
233
675
      MPI.Width *= 2;
234
819
    return MPI;
235
819
  }
236
237
2.82M
  CallingConv getDefaultMethodCallConv(bool isVariadic) const override {
238
2.82M
    const llvm::Triple &T = Context.getTargetInfo().getTriple();
239
2.82M
    if (!isVariadic && 
T.isWindowsGNUEnvironment()2.81M
&&
240
2.82M
        
T.getArch() == llvm::Triple::x867.33k
)
241
4.05k
      return CC_X86ThisCall;
242
2.82M
    return Context.getTargetInfo().getDefaultCallingConv();
243
2.82M
  }
244
245
  // We cheat and just check that the class has a vtable pointer, and that it's
246
  // only big enough to have a vtable pointer and nothing more (or less).
247
2.12k
  bool isNearlyEmpty(const CXXRecordDecl *RD) const override {
248
249
    // Check that the class has a vtable pointer.
250
2.12k
    if (!RD->isDynamicClass())
251
683
      return false;
252
253
1.44k
    const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
254
1.44k
    CharUnits PointerSize =
255
1.44k
      Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerWidth(0));
256
1.44k
    return Layout.getNonVirtualSize() == PointerSize;
257
2.12k
  }
258
259
  const CXXConstructorDecl *
260
0
  getCopyConstructorForExceptionObject(CXXRecordDecl *RD) override {
261
0
    return nullptr;
262
0
  }
263
264
  void addCopyConstructorForExceptionObject(CXXRecordDecl *RD,
265
0
                                            CXXConstructorDecl *CD) override {}
266
267
  void addTypedefNameForUnnamedTagDecl(TagDecl *TD,
268
151
                                       TypedefNameDecl *DD) override {}
269
270
948k
  TypedefNameDecl *getTypedefNameForUnnamedTagDecl(const TagDecl *TD) override {
271
948k
    return nullptr;
272
948k
  }
273
274
  void addDeclaratorForUnnamedTagDecl(TagDecl *TD,
275
10.5k
                                      DeclaratorDecl *DD) override {}
276
277
948k
  DeclaratorDecl *getDeclaratorForUnnamedTagDecl(const TagDecl *TD) override {
278
948k
    return nullptr;
279
948k
  }
280
281
  std::unique_ptr<MangleNumberingContext>
282
37.3k
  createMangleNumberingContext() const override {
283
37.3k
    if (Context.getLangOpts().isSYCL())
284
37
      return std::make_unique<ItaniumSYCLNumberingContext>(
285
37
          cast<ItaniumMangleContext>(Mangler.get()));
286
37.2k
    return std::make_unique<ItaniumNumberingContext>(
287
37.2k
        cast<ItaniumMangleContext>(Mangler.get()));
288
37.3k
  }
289
};
290
}
291
292
69.9k
CXXABI *clang::CreateItaniumCXXABI(ASTContext &Ctx) {
293
69.9k
  return new ItaniumCXXABI(Ctx);
294
69.9k
}
295
296
std::unique_ptr<MangleNumberingContext>
297
16
clang::createItaniumNumberingContext(MangleContext *Mangler) {
298
16
  return std::make_unique<ItaniumNumberingContext>(
299
16
      cast<ItaniumMangleContext>(Mangler));
300
16
}