Coverage Report

Created: 2020-02-18 08:44

/Users/buildslave/jenkins/workspace/coverage/llvm-project/clang/include/clang/Sema/ScopeInfo.h
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//===- ScopeInfo.h - Information about a semantic context -------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
9
// This file defines FunctionScopeInfo and its subclasses, which contain
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// information about a single function, block, lambda, or method body.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CLANG_SEMA_SCOPEINFO_H
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#define LLVM_CLANG_SEMA_SCOPEINFO_H
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#include "clang/AST/Expr.h"
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#include "clang/AST/ExprCXX.h"
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#include "clang/AST/Type.h"
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#include "clang/Basic/CapturedStmt.h"
21
#include "clang/Basic/LLVM.h"
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#include "clang/Basic/PartialDiagnostic.h"
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#include "clang/Basic/SourceLocation.h"
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#include "clang/Sema/CleanupInfo.h"
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#include "clang/Sema/DeclSpec.h"
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/ADT/DenseMapInfo.h"
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#include "llvm/ADT/MapVector.h"
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#include "llvm/ADT/PointerIntPair.h"
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#include "llvm/ADT/SmallPtrSet.h"
31
#include "llvm/ADT/SmallSet.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/ADT/StringRef.h"
34
#include "llvm/ADT/StringSwitch.h"
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#include "llvm/ADT/TinyPtrVector.h"
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#include "llvm/Support/Casting.h"
37
#include "llvm/Support/ErrorHandling.h"
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#include <algorithm>
39
#include <cassert>
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#include <utility>
41
42
namespace clang {
43
44
class BlockDecl;
45
class CapturedDecl;
46
class CXXMethodDecl;
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class CXXRecordDecl;
48
class ImplicitParamDecl;
49
class NamedDecl;
50
class ObjCIvarRefExpr;
51
class ObjCMessageExpr;
52
class ObjCPropertyDecl;
53
class ObjCPropertyRefExpr;
54
class ParmVarDecl;
55
class RecordDecl;
56
class ReturnStmt;
57
class Scope;
58
class Stmt;
59
class SwitchStmt;
60
class TemplateParameterList;
61
class TemplateTypeParmDecl;
62
class VarDecl;
63
64
namespace sema {
65
66
/// Contains information about the compound statement currently being
67
/// parsed.
68
class CompoundScopeInfo {
69
public:
70
  /// Whether this compound stamement contains `for' or `while' loops
71
  /// with empty bodies.
72
  bool HasEmptyLoopBodies = false;
73
74
  /// Whether this compound statement corresponds to a GNU statement
75
  /// expression.
76
  bool IsStmtExpr;
77
78
3.59M
  CompoundScopeInfo(bool IsStmtExpr) : IsStmtExpr(IsStmtExpr) {}
79
80
23.5k
  void setHasEmptyLoopBodies() {
81
23.5k
    HasEmptyLoopBodies = true;
82
23.5k
  }
83
};
84
85
class PossiblyUnreachableDiag {
86
public:
87
  PartialDiagnostic PD;
88
  SourceLocation Loc;
89
  llvm::TinyPtrVector<const Stmt*> Stmts;
90
91
  PossiblyUnreachableDiag(const PartialDiagnostic &PD, SourceLocation Loc,
92
                          ArrayRef<const Stmt *> Stmts)
93
61.7k
      : PD(PD), Loc(Loc), Stmts(Stmts) {}
94
};
95
96
/// Retains information about a function, method, or block that is
97
/// currently being parsed.
98
class FunctionScopeInfo {
99
protected:
100
  enum ScopeKind {
101
    SK_Function,
102
    SK_Block,
103
    SK_Lambda,
104
    SK_CapturedRegion
105
  };
106
107
public:
108
  /// What kind of scope we are describing.
109
  ScopeKind Kind : 3;
110
111
  /// Whether this function contains a VLA, \@try, try, C++
112
  /// initializer, or anything else that can't be jumped past.
113
  bool HasBranchProtectedScope : 1;
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115
  /// Whether this function contains any switches or direct gotos.
116
  bool HasBranchIntoScope : 1;
117
118
  /// Whether this function contains any indirect gotos.
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  bool HasIndirectGoto : 1;
120
121
  /// Whether a statement was dropped because it was invalid.
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  bool HasDroppedStmt : 1;
123
124
  /// True if current scope is for OpenMP declare reduction combiner.
125
  bool HasOMPDeclareReductionCombiner : 1;
126
127
  /// Whether there is a fallthrough statement in this function.
128
  bool HasFallthroughStmt : 1;
129
130
  /// Whether we make reference to a declaration that could be
131
  /// unavailable.
132
  bool HasPotentialAvailabilityViolations : 1;
133
134
  /// A flag that is set when parsing a method that must call super's
135
  /// implementation, such as \c -dealloc, \c -finalize, or any method marked
136
  /// with \c __attribute__((objc_requires_super)).
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  bool ObjCShouldCallSuper : 1;
138
139
  /// True when this is a method marked as a designated initializer.
140
  bool ObjCIsDesignatedInit : 1;
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142
  /// This starts true for a method marked as designated initializer and will
143
  /// be set to false if there is an invocation to a designated initializer of
144
  /// the super class.
145
  bool ObjCWarnForNoDesignatedInitChain : 1;
146
147
  /// True when this is an initializer method not marked as a designated
148
  /// initializer within a class that has at least one initializer marked as a
149
  /// designated initializer.
150
  bool ObjCIsSecondaryInit : 1;
151
152
  /// This starts true for a secondary initializer method and will be set to
153
  /// false if there is an invocation of an initializer on 'self'.
154
  bool ObjCWarnForNoInitDelegation : 1;
155
156
  /// True only when this function has not already built, or attempted
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  /// to build, the initial and final coroutine suspend points
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  bool NeedsCoroutineSuspends : 1;
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160
  /// An enumeration represeting the kind of the first coroutine statement
161
  /// in the function. One of co_return, co_await, or co_yield.
162
  unsigned char FirstCoroutineStmtKind : 2;
163
164
  /// First coroutine statement in the current function.
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  /// (ex co_return, co_await, co_yield)
166
  SourceLocation FirstCoroutineStmtLoc;
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168
  /// First 'return' statement in the current function.
169
  SourceLocation FirstReturnLoc;
170
171
  /// First C++ 'try' statement in the current function.
172
  SourceLocation FirstCXXTryLoc;
173
174
  /// First SEH '__try' statement in the current function.
175
  SourceLocation FirstSEHTryLoc;
176
177
  /// Used to determine if errors occurred in this function or block.
178
  DiagnosticErrorTrap ErrorTrap;
179
180
  /// A SwitchStmt, along with a flag indicating if its list of case statements
181
  /// is incomplete (because we dropped an invalid one while parsing).
182
  using SwitchInfo = llvm::PointerIntPair<SwitchStmt*, 1, bool>;
183
184
  /// SwitchStack - This is the current set of active switch statements in the
185
  /// block.
186
  SmallVector<SwitchInfo, 8> SwitchStack;
187
188
  /// The list of return statements that occur within the function or
189
  /// block, if there is any chance of applying the named return value
190
  /// optimization, or if we need to infer a return type.
191
  SmallVector<ReturnStmt*, 4> Returns;
192
193
  /// The promise object for this coroutine, if any.
194
  VarDecl *CoroutinePromise = nullptr;
195
196
  /// A mapping between the coroutine function parameters that were moved
197
  /// to the coroutine frame, and their move statements.
198
  llvm::SmallMapVector<ParmVarDecl *, Stmt *, 4> CoroutineParameterMoves;
199
200
  /// The initial and final coroutine suspend points.
201
  std::pair<Stmt *, Stmt *> CoroutineSuspends;
202
203
  /// The stack of currently active compound stamement scopes in the
204
  /// function.
205
  SmallVector<CompoundScopeInfo, 4> CompoundScopes;
206
207
  /// The set of blocks that are introduced in this function.
208
  llvm::SmallPtrSet<const BlockDecl *, 1> Blocks;
209
210
  /// The set of __block variables that are introduced in this function.
211
  llvm::TinyPtrVector<VarDecl *> ByrefBlockVars;
212
213
  /// A list of PartialDiagnostics created but delayed within the
214
  /// current function scope.  These diagnostics are vetted for reachability
215
  /// prior to being emitted.
216
  SmallVector<PossiblyUnreachableDiag, 4> PossiblyUnreachableDiags;
217
218
  /// A list of parameters which have the nonnull attribute and are
219
  /// modified in the function.
220
  llvm::SmallPtrSet<const ParmVarDecl *, 8> ModifiedNonNullParams;
221
222
public:
223
  /// Represents a simple identification of a weak object.
224
  ///
225
  /// Part of the implementation of -Wrepeated-use-of-weak.
226
  ///
227
  /// This is used to determine if two weak accesses refer to the same object.
228
  /// Here are some examples of how various accesses are "profiled":
229
  ///
230
  /// Access Expression |     "Base" Decl     |          "Property" Decl
231
  /// :---------------: | :-----------------: | :------------------------------:
232
  /// self.property     | self (VarDecl)      | property (ObjCPropertyDecl)
233
  /// self.implicitProp | self (VarDecl)      | -implicitProp (ObjCMethodDecl)
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  /// self->ivar.prop   | ivar (ObjCIvarDecl) | prop (ObjCPropertyDecl)
235
  /// cxxObj.obj.prop   | obj (FieldDecl)     | prop (ObjCPropertyDecl)
236
  /// [self foo].prop   | 0 (unknown)         | prop (ObjCPropertyDecl)
237
  /// self.prop1.prop2  | prop1 (ObjCPropertyDecl)    | prop2 (ObjCPropertyDecl)
238
  /// MyClass.prop      | MyClass (ObjCInterfaceDecl) | -prop (ObjCMethodDecl)
239
  /// MyClass.foo.prop  | +foo (ObjCMethodDecl)       | -prop (ObjCPropertyDecl)
240
  /// weakVar           | 0 (known)           | weakVar (VarDecl)
241
  /// self->weakIvar    | self (VarDecl)      | weakIvar (ObjCIvarDecl)
242
  ///
243
  /// Objects are identified with only two Decls to make it reasonably fast to
244
  /// compare them.
245
  class WeakObjectProfileTy {
246
    /// The base object decl, as described in the class documentation.
247
    ///
248
    /// The extra flag is "true" if the Base and Property are enough to uniquely
249
    /// identify the object in memory.
250
    ///
251
    /// \sa isExactProfile()
252
    using BaseInfoTy = llvm::PointerIntPair<const NamedDecl *, 1, bool>;
253
    BaseInfoTy Base;
254
255
    /// The "property" decl, as described in the class documentation.
256
    ///
257
    /// Note that this may not actually be an ObjCPropertyDecl, e.g. in the
258
    /// case of "implicit" properties (regular methods accessed via dot syntax).
259
    const NamedDecl *Property = nullptr;
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261
    /// Used to find the proper base profile for a given base expression.
262
    static BaseInfoTy getBaseInfo(const Expr *BaseE);
263
264
    inline WeakObjectProfileTy();
265
    static inline WeakObjectProfileTy getSentinel();
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267
  public:
268
    WeakObjectProfileTy(const ObjCPropertyRefExpr *RE);
269
    WeakObjectProfileTy(const Expr *Base, const ObjCPropertyDecl *Property);
270
    WeakObjectProfileTy(const DeclRefExpr *RE);
271
    WeakObjectProfileTy(const ObjCIvarRefExpr *RE);
272
273
18
    const NamedDecl *getBase() const { return Base.getPointer(); }
274
84
    const NamedDecl *getProperty() const { return Property; }
275
276
    /// Returns true if the object base specifies a known object in memory,
277
    /// rather than, say, an instance variable or property of another object.
278
    ///
279
    /// Note that this ignores the effects of aliasing; that is, \c foo.bar is
280
    /// considered an exact profile if \c foo is a local variable, even if
281
    /// another variable \c foo2 refers to the same object as \c foo.
282
    ///
283
    /// For increased precision, accesses with base variables that are
284
    /// properties or ivars of 'self' (e.g. self.prop1.prop2) are considered to
285
    /// be exact, though this is not true for arbitrary variables
286
    /// (foo.prop1.prop2).
287
102
    bool isExactProfile() const {
288
102
      return Base.getInt();
289
102
    }
290
291
4.76M
    bool operator==(const WeakObjectProfileTy &Other) const {
292
4.76M
      return Base == Other.Base && 
Property == Other.Property4.75M
;
293
4.76M
    }
294
295
    // For use in DenseMap.
296
    // We can't specialize the usual llvm::DenseMapInfo at the end of the file
297
    // because by that point the DenseMap in FunctionScopeInfo has already been
298
    // instantiated.
299
    class DenseMapInfo {
300
    public:
301
1.22M
      static inline WeakObjectProfileTy getEmptyKey() {
302
1.22M
        return WeakObjectProfileTy();
303
1.22M
      }
304
305
588k
      static inline WeakObjectProfileTy getTombstoneKey() {
306
588k
        return WeakObjectProfileTy::getSentinel();
307
588k
      }
308
309
344
      static unsigned getHashValue(const WeakObjectProfileTy &Val) {
310
344
        using Pair = std::pair<BaseInfoTy, const NamedDecl *>;
311
344
312
344
        return llvm::DenseMapInfo<Pair>::getHashValue(Pair(Val.Base,
313
344
                                                           Val.Property));
314
344
      }
315
316
      static bool isEqual(const WeakObjectProfileTy &LHS,
317
4.76M
                          const WeakObjectProfileTy &RHS) {
318
4.76M
        return LHS == RHS;
319
4.76M
      }
320
    };
321
  };
322
323
  /// Represents a single use of a weak object.
324
  ///
325
  /// Stores both the expression and whether the access is potentially unsafe
326
  /// (i.e. it could potentially be warned about).
327
  ///
328
  /// Part of the implementation of -Wrepeated-use-of-weak.
329
  class WeakUseTy {
330
    llvm::PointerIntPair<const Expr *, 1, bool> Rep;
331
332
  public:
333
324
    WeakUseTy(const Expr *Use, bool IsRead) : Rep(Use, IsRead) {}
334
335
486
    const Expr *getUseExpr() const { return Rep.getPointer(); }
336
270
    bool isUnsafe() const { return Rep.getInt(); }
337
44
    void markSafe() { Rep.setInt(false); }
338
339
50
    bool operator==(const WeakUseTy &Other) const {
340
50
      return Rep == Other.Rep;
341
50
    }
342
  };
343
344
  /// Used to collect uses of a particular weak object in a function body.
345
  ///
346
  /// Part of the implementation of -Wrepeated-use-of-weak.
347
  using WeakUseVector = SmallVector<WeakUseTy, 4>;
348
349
  /// Used to collect all uses of weak objects in a function body.
350
  ///
351
  /// Part of the implementation of -Wrepeated-use-of-weak.
352
  using WeakObjectUseMap =
353
      llvm::SmallDenseMap<WeakObjectProfileTy, WeakUseVector, 8,
354
                          WeakObjectProfileTy::DenseMapInfo>;
355
356
private:
357
  /// Used to collect all uses of weak objects in this function body.
358
  ///
359
  /// Part of the implementation of -Wrepeated-use-of-weak.
360
  WeakObjectUseMap WeakObjectUses;
361
362
protected:
363
6.98k
  FunctionScopeInfo(const FunctionScopeInfo&) = default;
364
365
public:
366
  FunctionScopeInfo(DiagnosticsEngine &Diag)
367
      : Kind(SK_Function), HasBranchProtectedScope(false),
368
        HasBranchIntoScope(false), HasIndirectGoto(false),
369
        HasDroppedStmt(false), HasOMPDeclareReductionCombiner(false),
370
        HasFallthroughStmt(false), HasPotentialAvailabilityViolations(false),
371
        ObjCShouldCallSuper(false), ObjCIsDesignatedInit(false),
372
        ObjCWarnForNoDesignatedInitChain(false), ObjCIsSecondaryInit(false),
373
        ObjCWarnForNoInitDelegation(false), NeedsCoroutineSuspends(true),
374
576k
        ErrorTrap(Diag) {}
375
376
  virtual ~FunctionScopeInfo();
377
378
  /// Record that a weak object was accessed.
379
  ///
380
  /// Part of the implementation of -Wrepeated-use-of-weak.
381
  template <typename ExprT>
382
  inline void recordUseOfWeak(const ExprT *E, bool IsRead = true);
383
384
  void recordUseOfWeak(const ObjCMessageExpr *Msg,
385
                       const ObjCPropertyDecl *Prop);
386
387
  /// Record that a given expression is a "safe" access of a weak object (e.g.
388
  /// assigning it to a strong variable.)
389
  ///
390
  /// Part of the implementation of -Wrepeated-use-of-weak.
391
  void markSafeWeakUse(const Expr *E);
392
393
111
  const WeakObjectUseMap &getWeakObjectUses() const {
394
111
    return WeakObjectUses;
395
111
  }
396
397
13.2k
  void setHasBranchIntoScope() {
398
13.2k
    HasBranchIntoScope = true;
399
13.2k
  }
400
401
1.26M
  void setHasBranchProtectedScope() {
402
1.26M
    HasBranchProtectedScope = true;
403
1.26M
  }
404
405
112
  void setHasIndirectGoto() {
406
112
    HasIndirectGoto = true;
407
112
  }
408
409
0
  void setHasDroppedStmt() {
410
0
    HasDroppedStmt = true;
411
0
  }
412
413
710
  void setHasOMPDeclareReductionCombiner() {
414
710
    HasOMPDeclareReductionCombiner = true;
415
710
  }
416
417
918
  void setHasFallthroughStmt() {
418
918
    HasFallthroughStmt = true;
419
918
  }
420
421
10.6k
  void setHasCXXTry(SourceLocation TryLoc) {
422
10.6k
    setHasBranchProtectedScope();
423
10.6k
    FirstCXXTryLoc = TryLoc;
424
10.6k
  }
425
426
263
  void setHasSEHTry(SourceLocation TryLoc) {
427
263
    setHasBranchProtectedScope();
428
263
    FirstSEHTryLoc = TryLoc;
429
263
  }
430
431
2.90M
  bool NeedsScopeChecking() const {
432
2.90M
    return !HasDroppedStmt &&
433
2.90M
        (HasIndirectGoto ||
434
2.90M
          
(2.90M
HasBranchProtectedScope2.90M
&&
HasBranchIntoScope204k
));
435
2.90M
  }
436
437
  // Add a block introduced in this function.
438
2.54k
  void addBlock(const BlockDecl *BD) {
439
2.54k
    Blocks.insert(BD);
440
2.54k
  }
441
442
  // Add a __block variable introduced in this function.
443
135
  void addByrefBlockVar(VarDecl *VD) {
444
135
    ByrefBlockVars.push_back(VD);
445
135
  }
446
447
311k
  bool isCoroutine() const { return !FirstCoroutineStmtLoc.isInvalid(); }
448
449
267
  void setFirstCoroutineStmt(SourceLocation Loc, StringRef Keyword) {
450
267
    assert(FirstCoroutineStmtLoc.isInvalid() &&
451
267
                   "first coroutine statement location already set");
452
267
    FirstCoroutineStmtLoc = Loc;
453
267
    FirstCoroutineStmtKind = llvm::StringSwitch<unsigned char>(Keyword)
454
267
            .Case("co_return", 0)
455
267
            .Case("co_await", 1)
456
267
            .Case("co_yield", 2);
457
267
  }
458
459
19
  StringRef getFirstCoroutineStmtKeyword() const {
460
19
    assert(FirstCoroutineStmtLoc.isValid()
461
19
                   && "no coroutine statement available");
462
19
    switch (FirstCoroutineStmtKind) {
463
10
    case 0: return "co_return";
464
4
    case 1: return "co_await";
465
5
    case 2: return "co_yield";
466
0
    default:
467
0
      llvm_unreachable("FirstCoroutineStmtKind has an invalid value");
468
0
    };
469
0
  }
470
471
254
  void setNeedsCoroutineSuspends(bool value = true) {
472
254
    assert((!value || CoroutineSuspends.first == nullptr) &&
473
254
            "we already have valid suspend points");
474
254
    NeedsCoroutineSuspends = value;
475
254
  }
476
477
246
  bool hasInvalidCoroutineSuspends() const {
478
246
    return !NeedsCoroutineSuspends && CoroutineSuspends.first == nullptr;
479
246
  }
480
481
245
  void setCoroutineSuspends(Stmt *Initial, Stmt *Final) {
482
245
    assert(Initial && Final && "suspend points cannot be null");
483
245
    assert(CoroutineSuspends.first == nullptr && "suspend points already set");
484
245
    NeedsCoroutineSuspends = false;
485
245
    CoroutineSuspends.first = Initial;
486
245
    CoroutineSuspends.second = Final;
487
245
  }
488
489
  /// Clear out the information in this function scope, making it
490
  /// suitable for reuse.
491
  void Clear();
492
493
3.40M
  bool isPlainFunction() const { return Kind == SK_Function; }
494
};
495
496
class Capture {
497
  // There are three categories of capture: capturing 'this', capturing
498
  // local variables, and C++1y initialized captures (which can have an
499
  // arbitrary initializer, and don't really capture in the traditional
500
  // sense at all).
501
  //
502
  // There are three ways to capture a local variable:
503
  //  - capture by copy in the C++11 sense,
504
  //  - capture by reference in the C++11 sense, and
505
  //  - __block capture.
506
  // Lambdas explicitly specify capture by copy or capture by reference.
507
  // For blocks, __block capture applies to variables with that annotation,
508
  // variables of reference type are captured by reference, and other
509
  // variables are captured by copy.
510
  enum CaptureKind {
511
    Cap_ByCopy, Cap_ByRef, Cap_Block, Cap_VLA
512
  };
513
514
  union {
515
    /// If Kind == Cap_VLA, the captured type.
516
    const VariableArrayType *CapturedVLA;
517
518
    /// Otherwise, the captured variable (if any).
519
    VarDecl *CapturedVar;
520
  };
521
522
  /// The source location at which the first capture occurred.
523
  SourceLocation Loc;
524
525
  /// The location of the ellipsis that expands a parameter pack.
526
  SourceLocation EllipsisLoc;
527
528
  /// The type as it was captured, which is the type of the non-static data
529
  /// member that would hold the capture.
530
  QualType CaptureType;
531
532
  /// The CaptureKind of this capture.
533
  unsigned Kind : 2;
534
535
  /// Whether this is a nested capture (a capture of an enclosing capturing
536
  /// scope's capture).
537
  unsigned Nested : 1;
538
539
  /// Whether this is a capture of '*this'.
540
  unsigned CapturesThis : 1;
541
542
  /// Whether an explicit capture has been odr-used in the body of the
543
  /// lambda.
544
  unsigned ODRUsed : 1;
545
546
  /// Whether an explicit capture has been non-odr-used in the body of
547
  /// the lambda.
548
  unsigned NonODRUsed : 1;
549
550
  /// Whether the capture is invalid (a capture was required but the entity is
551
  /// non-capturable).
552
  unsigned Invalid : 1;
553
554
public:
555
  Capture(VarDecl *Var, bool Block, bool ByRef, bool IsNested,
556
          SourceLocation Loc, SourceLocation EllipsisLoc, QualType CaptureType,
557
          bool Invalid)
558
      : CapturedVar(Var), Loc(Loc), EllipsisLoc(EllipsisLoc),
559
        CaptureType(CaptureType),
560
        Kind(Block ? Cap_Block : ByRef ? Cap_ByRef : Cap_ByCopy),
561
        Nested(IsNested), CapturesThis(false), ODRUsed(false),
562
333k
        NonODRUsed(false), Invalid(Invalid) {}
563
564
  enum IsThisCapture { ThisCapture };
565
  Capture(IsThisCapture, bool IsNested, SourceLocation Loc,
566
          QualType CaptureType, const bool ByCopy, bool Invalid)
567
      : Loc(Loc), CaptureType(CaptureType),
568
        Kind(ByCopy ? Cap_ByCopy : Cap_ByRef), Nested(IsNested),
569
        CapturesThis(true), ODRUsed(false), NonODRUsed(false),
570
9.38k
        Invalid(Invalid) {}
571
572
  enum IsVLACapture { VLACapture };
573
  Capture(IsVLACapture, const VariableArrayType *VLA, bool IsNested,
574
          SourceLocation Loc, QualType CaptureType)
575
      : CapturedVLA(VLA), Loc(Loc), CaptureType(CaptureType), Kind(Cap_VLA),
576
        Nested(IsNested), CapturesThis(false), ODRUsed(false),
577
6.68k
        NonODRUsed(false), Invalid(false) {}
578
579
3.05M
  bool isThisCapture() const { return CapturesThis; }
580
2.41M
  bool isVariableCapture() const {
581
2.41M
    return !isThisCapture() && 
!isVLATypeCapture()2.39M
;
582
2.41M
  }
583
584
835k
  bool isCopyCapture() const { return Kind == Cap_ByCopy; }
585
303k
  bool isReferenceCapture() const { return Kind == Cap_ByRef; }
586
7.95k
  bool isBlockCapture() const { return Kind == Cap_Block; }
587
3.45M
  bool isVLATypeCapture() const { return Kind == Cap_VLA; }
588
589
321k
  bool isNested() const { return Nested; }
590
591
327k
  bool isInvalid() const { return Invalid; }
592
593
  /// Determine whether this capture is an init-capture.
594
  bool isInitCapture() const;
595
596
1.28k
  bool isODRUsed() const { return ODRUsed; }
597
541
  bool isNonODRUsed() const { return NonODRUsed; }
598
826k
  void markUsed(bool IsODRUse) {
599
826k
    if (IsODRUse)
600
298k
      ODRUsed = true;
601
528k
    else
602
528k
      NonODRUsed = true;
603
826k
  }
604
605
1.35M
  VarDecl *getVariable() const {
606
1.35M
    assert(isVariableCapture());
607
1.35M
    return CapturedVar;
608
1.35M
  }
609
610
29.7k
  const VariableArrayType *getCapturedVLAType() const {
611
29.7k
    assert(isVLATypeCapture());
612
29.7k
    return CapturedVLA;
613
29.7k
  }
614
615
  /// Retrieve the location at which this variable was captured.
616
969k
  SourceLocation getLocation() const { return Loc; }
617
618
  /// Retrieve the source location of the ellipsis, whose presence
619
  /// indicates that the capture is a pack expansion.
620
4.25k
  SourceLocation getEllipsisLoc() const { return EllipsisLoc; }
621
622
  /// Retrieve the capture type for this capture, which is effectively
623
  /// the type of the non-static data member in the lambda/block structure
624
  /// that would store this capture.
625
1.14M
  QualType getCaptureType() const { return CaptureType; }
626
};
627
628
class CapturingScopeInfo : public FunctionScopeInfo {
629
protected:
630
6.98k
  CapturingScopeInfo(const CapturingScopeInfo&) = default;
631
632
public:
633
  enum ImplicitCaptureStyle {
634
    ImpCap_None, ImpCap_LambdaByval, ImpCap_LambdaByref, ImpCap_Block,
635
    ImpCap_CapturedRegion
636
  };
637
638
  ImplicitCaptureStyle ImpCaptureStyle;
639
640
  CapturingScopeInfo(DiagnosticsEngine &Diag, ImplicitCaptureStyle Style)
641
438k
      : FunctionScopeInfo(Diag), ImpCaptureStyle(Style) {}
642
643
  /// CaptureMap - A map of captured variables to (index+1) into Captures.
644
  llvm::DenseMap<VarDecl*, unsigned> CaptureMap;
645
646
  /// CXXThisCaptureIndex - The (index+1) of the capture of 'this';
647
  /// zero if 'this' is not captured.
648
  unsigned CXXThisCaptureIndex = 0;
649
650
  /// Captures - The captures.
651
  SmallVector<Capture, 4> Captures;
652
653
  /// - Whether the target type of return statements in this context
654
  /// is deduced (e.g. a lambda or block with omitted return type).
655
  bool HasImplicitReturnType = false;
656
657
  /// ReturnType - The target type of return statements in this context,
658
  /// or null if unknown.
659
  QualType ReturnType;
660
661
  void addCapture(VarDecl *Var, bool isBlock, bool isByref, bool isNested,
662
                  SourceLocation Loc, SourceLocation EllipsisLoc,
663
333k
                  QualType CaptureType, bool Invalid) {
664
333k
    Captures.push_back(Capture(Var, isBlock, isByref, isNested, Loc,
665
333k
                               EllipsisLoc, CaptureType, Invalid));
666
333k
    CaptureMap[Var] = Captures.size();
667
333k
  }
668
669
  void addVLATypeCapture(SourceLocation Loc, const VariableArrayType *VLAType,
670
6.68k
                         QualType CaptureType) {
671
6.68k
    Captures.push_back(Capture(Capture::VLACapture, VLAType,
672
6.68k
                               /*FIXME: IsNested*/ false, Loc, CaptureType));
673
6.68k
  }
674
675
  void addThisCapture(bool isNested, SourceLocation Loc, QualType CaptureType,
676
                      bool ByCopy);
677
678
  /// Determine whether the C++ 'this' is captured.
679
6.45k
  bool isCXXThisCaptured() const { return CXXThisCaptureIndex != 0; }
680
681
  /// Retrieve the capture of C++ 'this', if it has been captured.
682
2.29k
  Capture &getCXXThisCapture() {
683
2.29k
    assert(isCXXThisCaptured() && "this has not been captured");
684
2.29k
    return Captures[CXXThisCaptureIndex - 1];
685
2.29k
  }
686
687
  /// Determine whether the given variable has been captured.
688
2.45M
  bool isCaptured(VarDecl *Var) const {
689
2.45M
    return CaptureMap.count(Var);
690
2.45M
  }
691
692
  /// Determine whether the given variable-array type has been captured.
693
  bool isVLATypeCaptured(const VariableArrayType *VAT) const;
694
695
  /// Retrieve the capture of the given variable, if it has been
696
  /// captured already.
697
2.45M
  Capture &getCapture(VarDecl *Var) {
698
2.45M
    assert(isCaptured(Var) && "Variable has not been captured");
699
2.45M
    return Captures[CaptureMap[Var] - 1];
700
2.45M
  }
701
702
0
  const Capture &getCapture(VarDecl *Var) const {
703
0
    llvm::DenseMap<VarDecl*, unsigned>::const_iterator Known
704
0
      = CaptureMap.find(Var);
705
0
    assert(Known != CaptureMap.end() && "Variable has not been captured");
706
0
    return Captures[Known->second - 1];
707
0
  }
708
709
19.0M
  static bool classof(const FunctionScopeInfo *FSI) {
710
19.0M
    return FSI->Kind == SK_Block || 
FSI->Kind == SK_Lambda18.9M
711
19.0M
                                 || 
FSI->Kind == SK_CapturedRegion18.9M
;
712
19.0M
  }
713
};
714
715
/// Retains information about a block that is currently being parsed.
716
class BlockScopeInfo final : public CapturingScopeInfo {
717
public:
718
  BlockDecl *TheDecl;
719
720
  /// TheScope - This is the scope for the block itself, which contains
721
  /// arguments etc.
722
  Scope *TheScope;
723
724
  /// BlockType - The function type of the block, if one was given.
725
  /// Its return type may be BuiltinType::Dependent.
726
  QualType FunctionType;
727
728
  BlockScopeInfo(DiagnosticsEngine &Diag, Scope *BlockScope, BlockDecl *Block)
729
      : CapturingScopeInfo(Diag, ImpCap_Block), TheDecl(Block),
730
2.80k
        TheScope(BlockScope) {
731
2.80k
    Kind = SK_Block;
732
2.80k
  }
733
734
  ~BlockScopeInfo() override;
735
736
2.32M
  static bool classof(const FunctionScopeInfo *FSI) {
737
2.32M
    return FSI->Kind == SK_Block;
738
2.32M
  }
739
};
740
741
/// Retains information about a captured region.
742
class CapturedRegionScopeInfo final : public CapturingScopeInfo {
743
public:
744
  /// The CapturedDecl for this statement.
745
  CapturedDecl *TheCapturedDecl;
746
747
  /// The captured record type.
748
  RecordDecl *TheRecordDecl;
749
750
  /// This is the enclosing scope of the captured region.
751
  Scope *TheScope;
752
753
  /// The implicit parameter for the captured variables.
754
  ImplicitParamDecl *ContextParam;
755
756
  /// The kind of captured region.
757
  unsigned short CapRegionKind;
758
759
  unsigned short OpenMPLevel;
760
  unsigned short OpenMPCaptureLevel;
761
762
  CapturedRegionScopeInfo(DiagnosticsEngine &Diag, Scope *S, CapturedDecl *CD,
763
                          RecordDecl *RD, ImplicitParamDecl *Context,
764
                          CapturedRegionKind K, unsigned OpenMPLevel,
765
                          unsigned OpenMPCaptureLevel)
766
      : CapturingScopeInfo(Diag, ImpCap_CapturedRegion),
767
        TheCapturedDecl(CD), TheRecordDecl(RD), TheScope(S),
768
        ContextParam(Context), CapRegionKind(K), OpenMPLevel(OpenMPLevel),
769
427k
        OpenMPCaptureLevel(OpenMPCaptureLevel) {
770
427k
    Kind = SK_CapturedRegion;
771
427k
  }
772
773
  ~CapturedRegionScopeInfo() override;
774
775
  /// A descriptive name for the kind of captured region this is.
776
230
  StringRef getRegionName() const {
777
230
    switch (CapRegionKind) {
778
1
    case CR_Default:
779
1
      return "default captured statement";
780
0
    case CR_ObjCAtFinally:
781
0
      return "Objective-C @finally statement";
782
229
    case CR_OpenMP:
783
229
      return "OpenMP region";
784
0
    }
785
0
    llvm_unreachable("Invalid captured region kind!");
786
0
  }
787
788
6.82M
  static bool classof(const FunctionScopeInfo *FSI) {
789
6.82M
    return FSI->Kind == SK_CapturedRegion;
790
6.82M
  }
791
};
792
793
class LambdaScopeInfo final :
794
    public CapturingScopeInfo, public InventedTemplateParameterInfo {
795
public:
796
  /// The class that describes the lambda.
797
  CXXRecordDecl *Lambda = nullptr;
798
799
  /// The lambda's compiler-generated \c operator().
800
  CXXMethodDecl *CallOperator = nullptr;
801
802
  /// Source range covering the lambda introducer [...].
803
  SourceRange IntroducerRange;
804
805
  /// Source location of the '&' or '=' specifying the default capture
806
  /// type, if any.
807
  SourceLocation CaptureDefaultLoc;
808
809
  /// The number of captures in the \c Captures list that are
810
  /// explicit captures.
811
  unsigned NumExplicitCaptures = 0;
812
813
  /// Whether this is a mutable lambda.
814
  bool Mutable = false;
815
816
  /// Whether the (empty) parameter list is explicit.
817
  bool ExplicitParams = false;
818
819
  /// Whether any of the capture expressions requires cleanups.
820
  CleanupInfo Cleanup;
821
822
  /// Whether the lambda contains an unexpanded parameter pack.
823
  bool ContainsUnexpandedParameterPack = false;
824
825
  /// Packs introduced by this lambda, if any.
826
  SmallVector<NamedDecl*, 4> LocalPacks;
827
828
  /// Source range covering the explicit template parameter list (if it exists).
829
  SourceRange ExplicitTemplateParamsRange;
830
831
  /// If this is a generic lambda, and the template parameter
832
  /// list has been created (from the TemplateParams) then store
833
  /// a reference to it (cache it to avoid reconstructing it).
834
  TemplateParameterList *GLTemplateParameterList = nullptr;
835
836
  /// Contains all variable-referring-expressions (i.e. DeclRefExprs
837
  ///  or MemberExprs) that refer to local variables in a generic lambda
838
  ///  or a lambda in a potentially-evaluated-if-used context.
839
  ///
840
  ///  Potentially capturable variables of a nested lambda that might need
841
  ///   to be captured by the lambda are housed here.
842
  ///  This is specifically useful for generic lambdas or
843
  ///  lambdas within a potentially evaluated-if-used context.
844
  ///  If an enclosing variable is named in an expression of a lambda nested
845
  ///  within a generic lambda, we don't always know know whether the variable
846
  ///  will truly be odr-used (i.e. need to be captured) by that nested lambda,
847
  ///  until its instantiation. But we still need to capture it in the
848
  ///  enclosing lambda if all intervening lambdas can capture the variable.
849
  llvm::SmallVector<Expr*, 4> PotentiallyCapturingExprs;
850
851
  /// Contains all variable-referring-expressions that refer
852
  ///  to local variables that are usable as constant expressions and
853
  ///  do not involve an odr-use (they may still need to be captured
854
  ///  if the enclosing full-expression is instantiation dependent).
855
  llvm::SmallSet<Expr *, 8> NonODRUsedCapturingExprs;
856
857
  /// A map of explicit capture indices to their introducer source ranges.
858
  llvm::DenseMap<unsigned, SourceRange> ExplicitCaptureRanges;
859
860
  /// Contains all of the variables defined in this lambda that shadow variables
861
  /// that were defined in parent contexts. Used to avoid warnings when the
862
  /// shadowed variables are uncaptured by this lambda.
863
  struct ShadowedOuterDecl {
864
    const VarDecl *VD;
865
    const VarDecl *ShadowedDecl;
866
  };
867
  llvm::SmallVector<ShadowedOuterDecl, 4> ShadowingDecls;
868
869
  SourceLocation PotentialThisCaptureLocation;
870
871
  LambdaScopeInfo(DiagnosticsEngine &Diag)
872
8.45k
      : CapturingScopeInfo(Diag, ImpCap_None) {
873
8.45k
    Kind = SK_Lambda;
874
8.45k
  }
875
876
  /// Note when all explicit captures have been added.
877
7.15k
  void finishedExplicitCaptures() {
878
7.15k
    NumExplicitCaptures = Captures.size();
879
7.15k
  }
880
881
13.7M
  static bool classof(const FunctionScopeInfo *FSI) {
882
13.7M
    return FSI->Kind == SK_Lambda;
883
13.7M
  }
884
885
  /// Is this scope known to be for a generic lambda? (This will be false until
886
  /// we parse a template parameter list or the first 'auto'-typed parameter).
887
0
  bool isGenericLambda() const {
888
0
    return !TemplateParams.empty() || GLTemplateParameterList;
889
0
  }
890
891
  /// Add a variable that might potentially be captured by the
892
  /// lambda and therefore the enclosing lambdas.
893
  ///
894
  /// This is also used by enclosing lambda's to speculatively capture
895
  /// variables that nested lambda's - depending on their enclosing
896
  /// specialization - might need to capture.
897
  /// Consider:
898
  /// void f(int, int); <-- don't capture
899
  /// void f(const int&, double); <-- capture
900
  /// void foo() {
901
  ///   const int x = 10;
902
  ///   auto L = [=](auto a) { // capture 'x'
903
  ///      return [=](auto b) {
904
  ///        f(x, a);  // we may or may not need to capture 'x'
905
  ///      };
906
  ///   };
907
  /// }
908
546
  void addPotentialCapture(Expr *VarExpr) {
909
546
    assert(isa<DeclRefExpr>(VarExpr) || isa<MemberExpr>(VarExpr) ||
910
546
           isa<FunctionParmPackExpr>(VarExpr));
911
546
    PotentiallyCapturingExprs.push_back(VarExpr);
912
546
  }
913
914
38
  void addPotentialThisCapture(SourceLocation Loc) {
915
38
    PotentialThisCaptureLocation = Loc;
916
38
  }
917
918
486
  bool hasPotentialThisCapture() const {
919
486
    return PotentialThisCaptureLocation.isValid();
920
486
  }
921
922
  /// Mark a variable's reference in a lambda as non-odr using.
923
  ///
924
  /// For generic lambdas, if a variable is named in a potentially evaluated
925
  /// expression, where the enclosing full expression is dependent then we
926
  /// must capture the variable (given a default capture).
927
  /// This is accomplished by recording all references to variables
928
  /// (DeclRefExprs or MemberExprs) within said nested lambda in its array of
929
  /// PotentialCaptures. All such variables have to be captured by that lambda,
930
  /// except for as described below.
931
  /// If that variable is usable as a constant expression and is named in a
932
  /// manner that does not involve its odr-use (e.g. undergoes
933
  /// lvalue-to-rvalue conversion, or discarded) record that it is so. Upon the
934
  /// act of analyzing the enclosing full expression (ActOnFinishFullExpr)
935
  /// if we can determine that the full expression is not instantiation-
936
  /// dependent, then we can entirely avoid its capture.
937
  ///
938
  ///   const int n = 0;
939
  ///   [&] (auto x) {
940
  ///     (void)+n + x;
941
  ///   };
942
  /// Interestingly, this strategy would involve a capture of n, even though
943
  /// it's obviously not odr-used here, because the full-expression is
944
  /// instantiation-dependent.  It could be useful to avoid capturing such
945
  /// variables, even when they are referred to in an instantiation-dependent
946
  /// expression, if we can unambiguously determine that they shall never be
947
  /// odr-used.  This would involve removal of the variable-referring-expression
948
  /// from the array of PotentialCaptures during the lvalue-to-rvalue
949
  /// conversions.  But per the working draft N3797, (post-chicago 2013) we must
950
  /// capture such variables.
951
  /// Before anyone is tempted to implement a strategy for not-capturing 'n',
952
  /// consider the insightful warning in:
953
  ///    /cfe-commits/Week-of-Mon-20131104/092596.html
954
  /// "The problem is that the set of captures for a lambda is part of the ABI
955
  ///  (since lambda layout can be made visible through inline functions and the
956
  ///  like), and there are no guarantees as to which cases we'll manage to build
957
  ///  an lvalue-to-rvalue conversion in, when parsing a template -- some
958
  ///  seemingly harmless change elsewhere in Sema could cause us to start or stop
959
  ///  building such a node. So we need a rule that anyone can implement and get
960
  ///  exactly the same result".
961
359
  void markVariableExprAsNonODRUsed(Expr *CapturingVarExpr) {
962
359
    assert(isa<DeclRefExpr>(CapturingVarExpr) ||
963
359
           isa<MemberExpr>(CapturingVarExpr) ||
964
359
           isa<FunctionParmPackExpr>(CapturingVarExpr));
965
359
    NonODRUsedCapturingExprs.insert(CapturingVarExpr);
966
359
  }
967
558
  bool isVariableExprMarkedAsNonODRUsed(Expr *CapturingVarExpr) const {
968
558
    assert(isa<DeclRefExpr>(CapturingVarExpr) ||
969
558
           isa<MemberExpr>(CapturingVarExpr) ||
970
558
           isa<FunctionParmPackExpr>(CapturingVarExpr));
971
558
    return NonODRUsedCapturingExprs.count(CapturingVarExpr);
972
558
  }
973
0
  void removePotentialCapture(Expr *E) {
974
0
    PotentiallyCapturingExprs.erase(
975
0
        std::remove(PotentiallyCapturingExprs.begin(),
976
0
            PotentiallyCapturingExprs.end(), E),
977
0
        PotentiallyCapturingExprs.end());
978
0
  }
979
486
  void clearPotentialCaptures() {
980
486
    PotentiallyCapturingExprs.clear();
981
486
    PotentialThisCaptureLocation = SourceLocation();
982
486
  }
983
25.9k
  unsigned getNumPotentialVariableCaptures() const {
984
25.9k
    return PotentiallyCapturingExprs.size();
985
25.9k
  }
986
987
25.9k
  bool hasPotentialCaptures() const {
988
25.9k
    return getNumPotentialVariableCaptures() ||
989
25.9k
                                  
PotentialThisCaptureLocation.isValid()25.4k
;
990
25.9k
  }
991
992
  void visitPotentialCaptures(
993
      llvm::function_ref<void(VarDecl *, Expr *)> Callback) const;
994
};
995
996
FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy()
997
1.81M
    : Base(nullptr, false) {}
998
999
FunctionScopeInfo::WeakObjectProfileTy
1000
588k
FunctionScopeInfo::WeakObjectProfileTy::getSentinel() {
1001
588k
  FunctionScopeInfo::WeakObjectProfileTy Result;
1002
588k
  Result.Base.setInt(true);
1003
588k
  return Result;
1004
588k
}
1005
1006
template <typename ExprT>
1007
254
void FunctionScopeInfo::recordUseOfWeak(const ExprT *E, bool IsRead) {
1008
254
  assert(E);
1009
254
  WeakUseVector &Uses = WeakObjectUses[WeakObjectProfileTy(E)];
1010
254
  Uses.push_back(WeakUseTy(E, IsRead));
1011
254
}
void clang::sema::FunctionScopeInfo::recordUseOfWeak<clang::DeclRefExpr>(clang::DeclRefExpr const*, bool)
Line
Count
Source
1007
26
void FunctionScopeInfo::recordUseOfWeak(const ExprT *E, bool IsRead) {
1008
26
  assert(E);
1009
26
  WeakUseVector &Uses = WeakObjectUses[WeakObjectProfileTy(E)];
1010
26
  Uses.push_back(WeakUseTy(E, IsRead));
1011
26
}
void clang::sema::FunctionScopeInfo::recordUseOfWeak<clang::ObjCIvarRefExpr>(clang::ObjCIvarRefExpr const*, bool)
Line
Count
Source
1007
24
void FunctionScopeInfo::recordUseOfWeak(const ExprT *E, bool IsRead) {
1008
24
  assert(E);
1009
24
  WeakUseVector &Uses = WeakObjectUses[WeakObjectProfileTy(E)];
1010
24
  Uses.push_back(WeakUseTy(E, IsRead));
1011
24
}
void clang::sema::FunctionScopeInfo::recordUseOfWeak<clang::ObjCPropertyRefExpr>(clang::ObjCPropertyRefExpr const*, bool)
Line
Count
Source
1007
204
void FunctionScopeInfo::recordUseOfWeak(const ExprT *E, bool IsRead) {
1008
204
  assert(E);
1009
204
  WeakUseVector &Uses = WeakObjectUses[WeakObjectProfileTy(E)];
1010
204
  Uses.push_back(WeakUseTy(E, IsRead));
1011
204
}
1012
1013
inline void CapturingScopeInfo::addThisCapture(bool isNested,
1014
                                               SourceLocation Loc,
1015
                                               QualType CaptureType,
1016
9.38k
                                               bool ByCopy) {
1017
9.38k
  Captures.push_back(Capture(Capture::ThisCapture, isNested, Loc, CaptureType,
1018
9.38k
                             ByCopy, /*Invalid*/ false));
1019
9.38k
  CXXThisCaptureIndex = Captures.size();
1020
9.38k
}
1021
1022
} // namespace sema
1023
1024
} // namespace clang
1025
1026
#endif // LLVM_CLANG_SEMA_SCOPEINFO_H