Coverage Report

Created: 2020-11-24 06:42

/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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//
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// This file defines FunctionScopeInfo and its subclasses, which contain
10
// 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"
20
#include "clang/Basic/CapturedStmt.h"
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#include "clang/Basic/LLVM.h"
22
#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"
27
#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"
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#include "llvm/ADT/StringSwitch.h"
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#include "llvm/ADT/TinyPtrVector.h"
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#include "llvm/Support/Casting.h"
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#include "llvm/Support/ErrorHandling.h"
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#include <algorithm>
39
#include <cassert>
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#include <utility>
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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
4.19M
  CompoundScopeInfo(bool IsStmtExpr) : IsStmtExpr(IsStmtExpr) {}
79
80
24.9k
  void setHasEmptyLoopBodies() {
81
24.9k
    HasEmptyLoopBodies = true;
82
24.9k
  }
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
76.8k
      : 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
  };
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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;
114
115
  /// Whether this function contains any switches or direct gotos.
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  bool HasBranchIntoScope : 1;
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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;
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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 this function uses constrained floating point intrinsics
131
  bool UsesFPIntrin : 1;
132
133
  /// Whether we make reference to a declaration that could be
134
  /// unavailable.
135
  bool HasPotentialAvailabilityViolations : 1;
136
137
  /// A flag that is set when parsing a method that must call super's
138
  /// implementation, such as \c -dealloc, \c -finalize, or any method marked
139
  /// with \c __attribute__((objc_requires_super)).
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  bool ObjCShouldCallSuper : 1;
141
142
  /// True when this is a method marked as a designated initializer.
143
  bool ObjCIsDesignatedInit : 1;
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145
  /// This starts true for a method marked as designated initializer and will
146
  /// be set to false if there is an invocation to a designated initializer of
147
  /// the super class.
148
  bool ObjCWarnForNoDesignatedInitChain : 1;
149
150
  /// True when this is an initializer method not marked as a designated
151
  /// initializer within a class that has at least one initializer marked as a
152
  /// designated initializer.
153
  bool ObjCIsSecondaryInit : 1;
154
155
  /// This starts true for a secondary initializer method and will be set to
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  /// false if there is an invocation of an initializer on 'self'.
157
  bool ObjCWarnForNoInitDelegation : 1;
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159
  /// 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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  /// An enumeration represeting the kind of the first coroutine statement
164
  /// in the function. One of co_return, co_await, or co_yield.
165
  unsigned char FirstCoroutineStmtKind : 2;
166
167
  /// First coroutine statement in the current function.
168
  /// (ex co_return, co_await, co_yield)
169
  SourceLocation FirstCoroutineStmtLoc;
170
171
  /// First 'return' statement in the current function.
172
  SourceLocation FirstReturnLoc;
173
174
  /// First C++ 'try' statement in the current function.
175
  SourceLocation FirstCXXTryLoc;
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  /// First SEH '__try' statement in the current function.
178
  SourceLocation FirstSEHTryLoc;
179
180
private:
181
  /// Used to determine if errors occurred in this function or block.
182
  DiagnosticErrorTrap ErrorTrap;
183
184
public:
185
  /// A SwitchStmt, along with a flag indicating if its list of case statements
186
  /// is incomplete (because we dropped an invalid one while parsing).
187
  using SwitchInfo = llvm::PointerIntPair<SwitchStmt*, 1, bool>;
188
189
  /// SwitchStack - This is the current set of active switch statements in the
190
  /// block.
191
  SmallVector<SwitchInfo, 8> SwitchStack;
192
193
  /// The list of return statements that occur within the function or
194
  /// block, if there is any chance of applying the named return value
195
  /// optimization, or if we need to infer a return type.
196
  SmallVector<ReturnStmt*, 4> Returns;
197
198
  /// The promise object for this coroutine, if any.
199
  VarDecl *CoroutinePromise = nullptr;
200
201
  /// A mapping between the coroutine function parameters that were moved
202
  /// to the coroutine frame, and their move statements.
203
  llvm::SmallMapVector<ParmVarDecl *, Stmt *, 4> CoroutineParameterMoves;
204
205
  /// The initial and final coroutine suspend points.
206
  std::pair<Stmt *, Stmt *> CoroutineSuspends;
207
208
  /// The stack of currently active compound stamement scopes in the
209
  /// function.
210
  SmallVector<CompoundScopeInfo, 4> CompoundScopes;
211
212
  /// The set of blocks that are introduced in this function.
213
  llvm::SmallPtrSet<const BlockDecl *, 1> Blocks;
214
215
  /// The set of __block variables that are introduced in this function.
216
  llvm::TinyPtrVector<VarDecl *> ByrefBlockVars;
217
218
  /// A list of PartialDiagnostics created but delayed within the
219
  /// current function scope.  These diagnostics are vetted for reachability
220
  /// prior to being emitted.
221
  SmallVector<PossiblyUnreachableDiag, 4> PossiblyUnreachableDiags;
222
223
  /// A list of parameters which have the nonnull attribute and are
224
  /// modified in the function.
225
  llvm::SmallPtrSet<const ParmVarDecl *, 8> ModifiedNonNullParams;
226
227
public:
228
  /// Represents a simple identification of a weak object.
229
  ///
230
  /// Part of the implementation of -Wrepeated-use-of-weak.
231
  ///
232
  /// This is used to determine if two weak accesses refer to the same object.
233
  /// Here are some examples of how various accesses are "profiled":
234
  ///
235
  /// Access Expression |     "Base" Decl     |          "Property" Decl
236
  /// :---------------: | :-----------------: | :------------------------------:
237
  /// self.property     | self (VarDecl)      | property (ObjCPropertyDecl)
238
  /// self.implicitProp | self (VarDecl)      | -implicitProp (ObjCMethodDecl)
239
  /// self->ivar.prop   | ivar (ObjCIvarDecl) | prop (ObjCPropertyDecl)
240
  /// cxxObj.obj.prop   | obj (FieldDecl)     | prop (ObjCPropertyDecl)
241
  /// [self foo].prop   | 0 (unknown)         | prop (ObjCPropertyDecl)
242
  /// self.prop1.prop2  | prop1 (ObjCPropertyDecl)    | prop2 (ObjCPropertyDecl)
243
  /// MyClass.prop      | MyClass (ObjCInterfaceDecl) | -prop (ObjCMethodDecl)
244
  /// MyClass.foo.prop  | +foo (ObjCMethodDecl)       | -prop (ObjCPropertyDecl)
245
  /// weakVar           | 0 (known)           | weakVar (VarDecl)
246
  /// self->weakIvar    | self (VarDecl)      | weakIvar (ObjCIvarDecl)
247
  ///
248
  /// Objects are identified with only two Decls to make it reasonably fast to
249
  /// compare them.
250
  class WeakObjectProfileTy {
251
    /// The base object decl, as described in the class documentation.
252
    ///
253
    /// The extra flag is "true" if the Base and Property are enough to uniquely
254
    /// identify the object in memory.
255
    ///
256
    /// \sa isExactProfile()
257
    using BaseInfoTy = llvm::PointerIntPair<const NamedDecl *, 1, bool>;
258
    BaseInfoTy Base;
259
260
    /// The "property" decl, as described in the class documentation.
261
    ///
262
    /// Note that this may not actually be an ObjCPropertyDecl, e.g. in the
263
    /// case of "implicit" properties (regular methods accessed via dot syntax).
264
    const NamedDecl *Property = nullptr;
265
266
    /// Used to find the proper base profile for a given base expression.
267
    static BaseInfoTy getBaseInfo(const Expr *BaseE);
268
269
    inline WeakObjectProfileTy();
270
    static inline WeakObjectProfileTy getSentinel();
271
272
  public:
273
    WeakObjectProfileTy(const ObjCPropertyRefExpr *RE);
274
    WeakObjectProfileTy(const Expr *Base, const ObjCPropertyDecl *Property);
275
    WeakObjectProfileTy(const DeclRefExpr *RE);
276
    WeakObjectProfileTy(const ObjCIvarRefExpr *RE);
277
278
18
    const NamedDecl *getBase() const { return Base.getPointer(); }
279
84
    const NamedDecl *getProperty() const { return Property; }
280
281
    /// Returns true if the object base specifies a known object in memory,
282
    /// rather than, say, an instance variable or property of another object.
283
    ///
284
    /// Note that this ignores the effects of aliasing; that is, \c foo.bar is
285
    /// considered an exact profile if \c foo is a local variable, even if
286
    /// another variable \c foo2 refers to the same object as \c foo.
287
    ///
288
    /// For increased precision, accesses with base variables that are
289
    /// properties or ivars of 'self' (e.g. self.prop1.prop2) are considered to
290
    /// be exact, though this is not true for arbitrary variables
291
    /// (foo.prop1.prop2).
292
102
    bool isExactProfile() const {
293
102
      return Base.getInt();
294
102
    }
295
296
6.13M
    bool operator==(const WeakObjectProfileTy &Other) const {
297
6.13M
      return Base == Other.Base && 
Property == Other.Property6.13M
;
298
6.13M
    }
299
300
    // For use in DenseMap.
301
    // We can't specialize the usual llvm::DenseMapInfo at the end of the file
302
    // because by that point the DenseMap in FunctionScopeInfo has already been
303
    // instantiated.
304
    class DenseMapInfo {
305
    public:
306
1.58M
      static inline WeakObjectProfileTy getEmptyKey() {
307
1.58M
        return WeakObjectProfileTy();
308
1.58M
      }
309
310
757k
      static inline WeakObjectProfileTy getTombstoneKey() {
311
757k
        return WeakObjectProfileTy::getSentinel();
312
757k
      }
313
314
346
      static unsigned getHashValue(const WeakObjectProfileTy &Val) {
315
346
        using Pair = std::pair<BaseInfoTy, const NamedDecl *>;
316
317
346
        return llvm::DenseMapInfo<Pair>::getHashValue(Pair(Val.Base,
318
346
                                                           Val.Property));
319
346
      }
320
321
      static bool isEqual(const WeakObjectProfileTy &LHS,
322
6.13M
                          const WeakObjectProfileTy &RHS) {
323
6.13M
        return LHS == RHS;
324
6.13M
      }
325
    };
326
  };
327
328
  /// Represents a single use of a weak object.
329
  ///
330
  /// Stores both the expression and whether the access is potentially unsafe
331
  /// (i.e. it could potentially be warned about).
332
  ///
333
  /// Part of the implementation of -Wrepeated-use-of-weak.
334
  class WeakUseTy {
335
    llvm::PointerIntPair<const Expr *, 1, bool> Rep;
336
337
  public:
338
326
    WeakUseTy(const Expr *Use, bool IsRead) : Rep(Use, IsRead) {}
339
340
487
    const Expr *getUseExpr() const { return Rep.getPointer(); }
341
271
    bool isUnsafe() const { return Rep.getInt(); }
342
44
    void markSafe() { Rep.setInt(false); }
343
344
50
    bool operator==(const WeakUseTy &Other) const {
345
50
      return Rep == Other.Rep;
346
50
    }
347
  };
348
349
  /// Used to collect uses of a particular weak object in a function body.
350
  ///
351
  /// Part of the implementation of -Wrepeated-use-of-weak.
352
  using WeakUseVector = SmallVector<WeakUseTy, 4>;
353
354
  /// Used to collect all uses of weak objects in a function body.
355
  ///
356
  /// Part of the implementation of -Wrepeated-use-of-weak.
357
  using WeakObjectUseMap =
358
      llvm::SmallDenseMap<WeakObjectProfileTy, WeakUseVector, 8,
359
                          WeakObjectProfileTy::DenseMapInfo>;
360
361
private:
362
  /// Used to collect all uses of weak objects in this function body.
363
  ///
364
  /// Part of the implementation of -Wrepeated-use-of-weak.
365
  WeakObjectUseMap WeakObjectUses;
366
367
protected:
368
9.42k
  FunctionScopeInfo(const FunctionScopeInfo&) = default;
369
370
public:
371
  FunctionScopeInfo(DiagnosticsEngine &Diag)
372
      : Kind(SK_Function), HasBranchProtectedScope(false),
373
        HasBranchIntoScope(false), HasIndirectGoto(false),
374
        HasDroppedStmt(false), HasOMPDeclareReductionCombiner(false),
375
        HasFallthroughStmt(false), UsesFPIntrin(false),
376
        HasPotentialAvailabilityViolations(false),
377
        ObjCShouldCallSuper(false), ObjCIsDesignatedInit(false),
378
        ObjCWarnForNoDesignatedInitChain(false), ObjCIsSecondaryInit(false),
379
        ObjCWarnForNoInitDelegation(false), NeedsCoroutineSuspends(true),
380
741k
        ErrorTrap(Diag) {}
381
382
  virtual ~FunctionScopeInfo();
383
384
  /// Determine whether an unrecoverable error has occurred within this
385
  /// function. Note that this may return false even if the function body is
386
  /// invalid, because the errors may be suppressed if they're caused by prior
387
  /// invalid declarations.
388
  ///
389
  /// FIXME: Migrate the caller of this to use containsErrors() instead once
390
  /// it's ready.
391
17.1k
  bool hasUnrecoverableErrorOccurred() const {
392
17.1k
    return ErrorTrap.hasUnrecoverableErrorOccurred();
393
17.1k
  }
394
395
  /// Record that a weak object was accessed.
396
  ///
397
  /// Part of the implementation of -Wrepeated-use-of-weak.
398
  template <typename ExprT>
399
  inline void recordUseOfWeak(const ExprT *E, bool IsRead = true);
400
401
  void recordUseOfWeak(const ObjCMessageExpr *Msg,
402
                       const ObjCPropertyDecl *Prop);
403
404
  /// Record that a given expression is a "safe" access of a weak object (e.g.
405
  /// assigning it to a strong variable.)
406
  ///
407
  /// Part of the implementation of -Wrepeated-use-of-weak.
408
  void markSafeWeakUse(const Expr *E);
409
410
112
  const WeakObjectUseMap &getWeakObjectUses() const {
411
112
    return WeakObjectUses;
412
112
  }
413
414
13.5k
  void setHasBranchIntoScope() {
415
13.5k
    HasBranchIntoScope = true;
416
13.5k
  }
417
418
1.51M
  void setHasBranchProtectedScope() {
419
1.51M
    HasBranchProtectedScope = true;
420
1.51M
  }
421
422
127
  void setHasIndirectGoto() {
423
127
    HasIndirectGoto = true;
424
127
  }
425
426
0
  void setHasDroppedStmt() {
427
0
    HasDroppedStmt = true;
428
0
  }
429
430
752
  void setHasOMPDeclareReductionCombiner() {
431
752
    HasOMPDeclareReductionCombiner = true;
432
752
  }
433
434
965
  void setHasFallthroughStmt() {
435
965
    HasFallthroughStmt = true;
436
965
  }
437
438
96.5k
  void setUsesFPIntrin() {
439
96.5k
    UsesFPIntrin = true;
440
96.5k
  }
441
442
10.5k
  void setHasCXXTry(SourceLocation TryLoc) {
443
10.5k
    setHasBranchProtectedScope();
444
10.5k
    FirstCXXTryLoc = TryLoc;
445
10.5k
  }
446
447
267
  void setHasSEHTry(SourceLocation TryLoc) {
448
267
    setHasBranchProtectedScope();
449
267
    FirstSEHTryLoc = TryLoc;
450
267
  }
451
452
3.38M
  bool NeedsScopeChecking() const {
453
3.38M
    return !HasDroppedStmt &&
454
3.38M
        (HasIndirectGoto ||
455
3.38M
          (HasBranchProtectedScope && 
HasBranchIntoScope223k
));
456
3.38M
  }
457
458
  // Add a block introduced in this function.
459
2.63k
  void addBlock(const BlockDecl *BD) {
460
2.63k
    Blocks.insert(BD);
461
2.63k
  }
462
463
  // Add a __block variable introduced in this function.
464
135
  void addByrefBlockVar(VarDecl *VD) {
465
135
    ByrefBlockVars.push_back(VD);
466
135
  }
467
468
408k
  bool isCoroutine() const { return !FirstCoroutineStmtLoc.isInvalid(); }
469
470
285
  void setFirstCoroutineStmt(SourceLocation Loc, StringRef Keyword) {
471
285
    assert(FirstCoroutineStmtLoc.isInvalid() &&
472
285
                   "first coroutine statement location already set");
473
285
    FirstCoroutineStmtLoc = Loc;
474
285
    FirstCoroutineStmtKind = llvm::StringSwitch<unsigned char>(Keyword)
475
285
            .Case("co_return", 0)
476
285
            .Case("co_await", 1)
477
285
            .Case("co_yield", 2);
478
285
  }
479
480
19
  StringRef getFirstCoroutineStmtKeyword() const {
481
19
    assert(FirstCoroutineStmtLoc.isValid()
482
19
                   && "no coroutine statement available");
483
19
    switch (FirstCoroutineStmtKind) {
484
10
    case 0: return "co_return";
485
4
    case 1: return "co_await";
486
5
    case 2: return "co_yield";
487
0
    default:
488
0
      llvm_unreachable("FirstCoroutineStmtKind has an invalid value");
489
0
    };
490
0
  }
491
492
273
  void setNeedsCoroutineSuspends(bool value = true) {
493
273
    assert((!value || CoroutineSuspends.first == nullptr) &&
494
273
            "we already have valid suspend points");
495
273
    NeedsCoroutineSuspends = value;
496
273
  }
497
498
264
  bool hasInvalidCoroutineSuspends() const {
499
264
    return !NeedsCoroutineSuspends && CoroutineSuspends.first == nullptr;
500
264
  }
501
502
262
  void setCoroutineSuspends(Stmt *Initial, Stmt *Final) {
503
262
    assert(Initial && Final && "suspend points cannot be null");
504
262
    assert(CoroutineSuspends.first == nullptr && "suspend points already set");
505
262
    NeedsCoroutineSuspends = false;
506
262
    CoroutineSuspends.first = Initial;
507
262
    CoroutineSuspends.second = Final;
508
262
  }
509
510
  /// Clear out the information in this function scope, making it
511
  /// suitable for reuse.
512
  void Clear();
513
514
4.01M
  bool isPlainFunction() const { return Kind == SK_Function; }
515
};
516
517
class Capture {
518
  // There are three categories of capture: capturing 'this', capturing
519
  // local variables, and C++1y initialized captures (which can have an
520
  // arbitrary initializer, and don't really capture in the traditional
521
  // sense at all).
522
  //
523
  // There are three ways to capture a local variable:
524
  //  - capture by copy in the C++11 sense,
525
  //  - capture by reference in the C++11 sense, and
526
  //  - __block capture.
527
  // Lambdas explicitly specify capture by copy or capture by reference.
528
  // For blocks, __block capture applies to variables with that annotation,
529
  // variables of reference type are captured by reference, and other
530
  // variables are captured by copy.
531
  enum CaptureKind {
532
    Cap_ByCopy, Cap_ByRef, Cap_Block, Cap_VLA
533
  };
534
535
  union {
536
    /// If Kind == Cap_VLA, the captured type.
537
    const VariableArrayType *CapturedVLA;
538
539
    /// Otherwise, the captured variable (if any).
540
    VarDecl *CapturedVar;
541
  };
542
543
  /// The source location at which the first capture occurred.
544
  SourceLocation Loc;
545
546
  /// The location of the ellipsis that expands a parameter pack.
547
  SourceLocation EllipsisLoc;
548
549
  /// The type as it was captured, which is the type of the non-static data
550
  /// member that would hold the capture.
551
  QualType CaptureType;
552
553
  /// The CaptureKind of this capture.
554
  unsigned Kind : 2;
555
556
  /// Whether this is a nested capture (a capture of an enclosing capturing
557
  /// scope's capture).
558
  unsigned Nested : 1;
559
560
  /// Whether this is a capture of '*this'.
561
  unsigned CapturesThis : 1;
562
563
  /// Whether an explicit capture has been odr-used in the body of the
564
  /// lambda.
565
  unsigned ODRUsed : 1;
566
567
  /// Whether an explicit capture has been non-odr-used in the body of
568
  /// the lambda.
569
  unsigned NonODRUsed : 1;
570
571
  /// Whether the capture is invalid (a capture was required but the entity is
572
  /// non-capturable).
573
  unsigned Invalid : 1;
574
575
public:
576
  Capture(VarDecl *Var, bool Block, bool ByRef, bool IsNested,
577
          SourceLocation Loc, SourceLocation EllipsisLoc, QualType CaptureType,
578
          bool Invalid)
579
      : CapturedVar(Var), Loc(Loc), EllipsisLoc(EllipsisLoc),
580
        CaptureType(CaptureType),
581
        Kind(Block ? Cap_Block : ByRef ? Cap_ByRef : Cap_ByCopy),
582
        Nested(IsNested), CapturesThis(false), ODRUsed(false),
583
399k
        NonODRUsed(false), Invalid(Invalid) {}
584
585
  enum IsThisCapture { ThisCapture };
586
  Capture(IsThisCapture, bool IsNested, SourceLocation Loc,
587
          QualType CaptureType, const bool ByCopy, bool Invalid)
588
      : Loc(Loc), CaptureType(CaptureType),
589
        Kind(ByCopy ? Cap_ByCopy : Cap_ByRef), Nested(IsNested),
590
        CapturesThis(true), ODRUsed(false), NonODRUsed(false),
591
11.4k
        Invalid(Invalid) {}
592
593
  enum IsVLACapture { VLACapture };
594
  Capture(IsVLACapture, const VariableArrayType *VLA, bool IsNested,
595
          SourceLocation Loc, QualType CaptureType)
596
      : CapturedVLA(VLA), Loc(Loc), CaptureType(CaptureType), Kind(Cap_VLA),
597
        Nested(IsNested), CapturesThis(false), ODRUsed(false),
598
8.82k
        NonODRUsed(false), Invalid(false) {}
599
600
3.64M
  bool isThisCapture() const { return CapturesThis; }
601
2.87M
  bool isVariableCapture() const {
602
2.87M
    return !isThisCapture() && 
!isVLATypeCapture()2.86M
;
603
2.87M
  }
604
605
970k
  bool isCopyCapture() const { return Kind == Cap_ByCopy; }
606
364k
  bool isReferenceCapture() const { return Kind == Cap_ByRef; }
607
8.42k
  bool isBlockCapture() const { return Kind == Cap_Block; }
608
4.13M
  bool isVLATypeCapture() const { return Kind == Cap_VLA; }
609
610
383k
  bool isNested() const { return Nested; }
611
612
391k
  bool isInvalid() const { return Invalid; }
613
614
  /// Determine whether this capture is an init-capture.
615
  bool isInitCapture() const;
616
617
1.38k
  bool isODRUsed() const { return ODRUsed; }
618
593
  bool isNonODRUsed() const { return NonODRUsed; }
619
960k
  void markUsed(bool IsODRUse) {
620
960k
    if (IsODRUse)
621
346k
      ODRUsed = true;
622
614k
    else
623
614k
      NonODRUsed = true;
624
960k
  }
625
626
1.61M
  VarDecl *getVariable() const {
627
1.61M
    assert(isVariableCapture());
628
1.61M
    return CapturedVar;
629
1.61M
  }
630
631
39.8k
  const VariableArrayType *getCapturedVLAType() const {
632
39.8k
    assert(isVLATypeCapture());
633
39.8k
    return CapturedVLA;
634
39.8k
  }
635
636
  /// Retrieve the location at which this variable was captured.
637
1.16M
  SourceLocation getLocation() const { return Loc; }
638
639
  /// Retrieve the source location of the ellipsis, whose presence
640
  /// indicates that the capture is a pack expansion.
641
4.57k
  SourceLocation getEllipsisLoc() const { return EllipsisLoc; }
642
643
  /// Retrieve the capture type for this capture, which is effectively
644
  /// the type of the non-static data member in the lambda/block structure
645
  /// that would store this capture.
646
1.34M
  QualType getCaptureType() const { return CaptureType; }
647
};
648
649
class CapturingScopeInfo : public FunctionScopeInfo {
650
protected:
651
9.42k
  CapturingScopeInfo(const CapturingScopeInfo&) = default;
652
653
public:
654
  enum ImplicitCaptureStyle {
655
    ImpCap_None, ImpCap_LambdaByval, ImpCap_LambdaByref, ImpCap_Block,
656
    ImpCap_CapturedRegion
657
  };
658
659
  ImplicitCaptureStyle ImpCaptureStyle;
660
661
  CapturingScopeInfo(DiagnosticsEngine &Diag, ImplicitCaptureStyle Style)
662
568k
      : FunctionScopeInfo(Diag), ImpCaptureStyle(Style) {}
663
664
  /// CaptureMap - A map of captured variables to (index+1) into Captures.
665
  llvm::DenseMap<VarDecl*, unsigned> CaptureMap;
666
667
  /// CXXThisCaptureIndex - The (index+1) of the capture of 'this';
668
  /// zero if 'this' is not captured.
669
  unsigned CXXThisCaptureIndex = 0;
670
671
  /// Captures - The captures.
672
  SmallVector<Capture, 4> Captures;
673
674
  /// - Whether the target type of return statements in this context
675
  /// is deduced (e.g. a lambda or block with omitted return type).
676
  bool HasImplicitReturnType = false;
677
678
  /// ReturnType - The target type of return statements in this context,
679
  /// or null if unknown.
680
  QualType ReturnType;
681
682
  void addCapture(VarDecl *Var, bool isBlock, bool isByref, bool isNested,
683
                  SourceLocation Loc, SourceLocation EllipsisLoc,
684
399k
                  QualType CaptureType, bool Invalid) {
685
399k
    Captures.push_back(Capture(Var, isBlock, isByref, isNested, Loc,
686
399k
                               EllipsisLoc, CaptureType, Invalid));
687
399k
    CaptureMap[Var] = Captures.size();
688
399k
  }
689
690
  void addVLATypeCapture(SourceLocation Loc, const VariableArrayType *VLAType,
691
8.82k
                         QualType CaptureType) {
692
8.82k
    Captures.push_back(Capture(Capture::VLACapture, VLAType,
693
8.82k
                               /*FIXME: IsNested*/ false, Loc, CaptureType));
694
8.82k
  }
695
696
  void addThisCapture(bool isNested, SourceLocation Loc, QualType CaptureType,
697
                      bool ByCopy);
698
699
  /// Determine whether the C++ 'this' is captured.
700
7.36k
  bool isCXXThisCaptured() const { return CXXThisCaptureIndex != 0; }
701
702
  /// Retrieve the capture of C++ 'this', if it has been captured.
703
2.52k
  Capture &getCXXThisCapture() {
704
2.52k
    assert(isCXXThisCaptured() && "this has not been captured");
705
2.52k
    return Captures[CXXThisCaptureIndex - 1];
706
2.52k
  }
707
708
  /// Determine whether the given variable has been captured.
709
2.84M
  bool isCaptured(VarDecl *Var) const {
710
2.84M
    return CaptureMap.count(Var);
711
2.84M
  }
712
713
  /// Determine whether the given variable-array type has been captured.
714
  bool isVLATypeCaptured(const VariableArrayType *VAT) const;
715
716
  /// Retrieve the capture of the given variable, if it has been
717
  /// captured already.
718
2.84M
  Capture &getCapture(VarDecl *Var) {
719
2.84M
    assert(isCaptured(Var) && "Variable has not been captured");
720
2.84M
    return Captures[CaptureMap[Var] - 1];
721
2.84M
  }
722
723
0
  const Capture &getCapture(VarDecl *Var) const {
724
0
    llvm::DenseMap<VarDecl*, unsigned>::const_iterator Known
725
0
      = CaptureMap.find(Var);
726
0
    assert(Known != CaptureMap.end() && "Variable has not been captured");
727
0
    return Captures[Known->second - 1];
728
0
  }
729
730
22.5M
  static bool classof(const FunctionScopeInfo *FSI) {
731
22.5M
    return FSI->Kind == SK_Block || 
FSI->Kind == SK_Lambda22.5M
732
22.4M
                                 || FSI->Kind == SK_CapturedRegion;
733
22.5M
  }
734
};
735
736
/// Retains information about a block that is currently being parsed.
737
class BlockScopeInfo final : public CapturingScopeInfo {
738
public:
739
  BlockDecl *TheDecl;
740
741
  /// TheScope - This is the scope for the block itself, which contains
742
  /// arguments etc.
743
  Scope *TheScope;
744
745
  /// BlockType - The function type of the block, if one was given.
746
  /// Its return type may be BuiltinType::Dependent.
747
  QualType FunctionType;
748
749
  BlockScopeInfo(DiagnosticsEngine &Diag, Scope *BlockScope, BlockDecl *Block)
750
      : CapturingScopeInfo(Diag, ImpCap_Block), TheDecl(Block),
751
2.89k
        TheScope(BlockScope) {
752
2.89k
    Kind = SK_Block;
753
2.89k
  }
754
755
  ~BlockScopeInfo() override;
756
757
2.92M
  static bool classof(const FunctionScopeInfo *FSI) {
758
2.92M
    return FSI->Kind == SK_Block;
759
2.92M
  }
760
};
761
762
/// Retains information about a captured region.
763
class CapturedRegionScopeInfo final : public CapturingScopeInfo {
764
public:
765
  /// The CapturedDecl for this statement.
766
  CapturedDecl *TheCapturedDecl;
767
768
  /// The captured record type.
769
  RecordDecl *TheRecordDecl;
770
771
  /// This is the enclosing scope of the captured region.
772
  Scope *TheScope;
773
774
  /// The implicit parameter for the captured variables.
775
  ImplicitParamDecl *ContextParam;
776
777
  /// The kind of captured region.
778
  unsigned short CapRegionKind;
779
780
  unsigned short OpenMPLevel;
781
  unsigned short OpenMPCaptureLevel;
782
783
  CapturedRegionScopeInfo(DiagnosticsEngine &Diag, Scope *S, CapturedDecl *CD,
784
                          RecordDecl *RD, ImplicitParamDecl *Context,
785
                          CapturedRegionKind K, unsigned OpenMPLevel,
786
                          unsigned OpenMPCaptureLevel)
787
      : CapturingScopeInfo(Diag, ImpCap_CapturedRegion),
788
        TheCapturedDecl(CD), TheRecordDecl(RD), TheScope(S),
789
        ContextParam(Context), CapRegionKind(K), OpenMPLevel(OpenMPLevel),
790
553k
        OpenMPCaptureLevel(OpenMPCaptureLevel) {
791
553k
    Kind = SK_CapturedRegion;
792
553k
  }
793
794
  ~CapturedRegionScopeInfo() override;
795
796
  /// A descriptive name for the kind of captured region this is.
797
239
  StringRef getRegionName() const {
798
239
    switch (CapRegionKind) {
799
1
    case CR_Default:
800
1
      return "default captured statement";
801
0
    case CR_ObjCAtFinally:
802
0
      return "Objective-C @finally statement";
803
238
    case CR_OpenMP:
804
238
      return "OpenMP region";
805
0
    }
806
0
    llvm_unreachable("Invalid captured region kind!");
807
0
  }
808
809
8.60M
  static bool classof(const FunctionScopeInfo *FSI) {
810
8.60M
    return FSI->Kind == SK_CapturedRegion;
811
8.60M
  }
812
};
813
814
class LambdaScopeInfo final :
815
    public CapturingScopeInfo, public InventedTemplateParameterInfo {
816
public:
817
  /// The class that describes the lambda.
818
  CXXRecordDecl *Lambda = nullptr;
819
820
  /// The lambda's compiler-generated \c operator().
821
  CXXMethodDecl *CallOperator = nullptr;
822
823
  /// Source range covering the lambda introducer [...].
824
  SourceRange IntroducerRange;
825
826
  /// Source location of the '&' or '=' specifying the default capture
827
  /// type, if any.
828
  SourceLocation CaptureDefaultLoc;
829
830
  /// The number of captures in the \c Captures list that are
831
  /// explicit captures.
832
  unsigned NumExplicitCaptures = 0;
833
834
  /// Whether this is a mutable lambda.
835
  bool Mutable = false;
836
837
  /// Whether the (empty) parameter list is explicit.
838
  bool ExplicitParams = false;
839
840
  /// Whether any of the capture expressions requires cleanups.
841
  CleanupInfo Cleanup;
842
843
  /// Whether the lambda contains an unexpanded parameter pack.
844
  bool ContainsUnexpandedParameterPack = false;
845
846
  /// Packs introduced by this lambda, if any.
847
  SmallVector<NamedDecl*, 4> LocalPacks;
848
849
  /// Source range covering the explicit template parameter list (if it exists).
850
  SourceRange ExplicitTemplateParamsRange;
851
852
  /// If this is a generic lambda, and the template parameter
853
  /// list has been created (from the TemplateParams) then store
854
  /// a reference to it (cache it to avoid reconstructing it).
855
  TemplateParameterList *GLTemplateParameterList = nullptr;
856
857
  /// Contains all variable-referring-expressions (i.e. DeclRefExprs
858
  ///  or MemberExprs) that refer to local variables in a generic lambda
859
  ///  or a lambda in a potentially-evaluated-if-used context.
860
  ///
861
  ///  Potentially capturable variables of a nested lambda that might need
862
  ///   to be captured by the lambda are housed here.
863
  ///  This is specifically useful for generic lambdas or
864
  ///  lambdas within a potentially evaluated-if-used context.
865
  ///  If an enclosing variable is named in an expression of a lambda nested
866
  ///  within a generic lambda, we don't always know know whether the variable
867
  ///  will truly be odr-used (i.e. need to be captured) by that nested lambda,
868
  ///  until its instantiation. But we still need to capture it in the
869
  ///  enclosing lambda if all intervening lambdas can capture the variable.
870
  llvm::SmallVector<Expr*, 4> PotentiallyCapturingExprs;
871
872
  /// Contains all variable-referring-expressions that refer
873
  ///  to local variables that are usable as constant expressions and
874
  ///  do not involve an odr-use (they may still need to be captured
875
  ///  if the enclosing full-expression is instantiation dependent).
876
  llvm::SmallSet<Expr *, 8> NonODRUsedCapturingExprs;
877
878
  /// A map of explicit capture indices to their introducer source ranges.
879
  llvm::DenseMap<unsigned, SourceRange> ExplicitCaptureRanges;
880
881
  /// Contains all of the variables defined in this lambda that shadow variables
882
  /// that were defined in parent contexts. Used to avoid warnings when the
883
  /// shadowed variables are uncaptured by this lambda.
884
  struct ShadowedOuterDecl {
885
    const VarDecl *VD;
886
    const VarDecl *ShadowedDecl;
887
  };
888
  llvm::SmallVector<ShadowedOuterDecl, 4> ShadowingDecls;
889
890
  SourceLocation PotentialThisCaptureLocation;
891
892
  LambdaScopeInfo(DiagnosticsEngine &Diag)
893
12.0k
      : CapturingScopeInfo(Diag, ImpCap_None) {
894
12.0k
    Kind = SK_Lambda;
895
12.0k
  }
896
897
  /// Note when all explicit captures have been added.
898
9.61k
  void finishedExplicitCaptures() {
899
9.61k
    NumExplicitCaptures = Captures.size();
900
9.61k
  }
901
902
16.3M
  static bool classof(const FunctionScopeInfo *FSI) {
903
16.3M
    return FSI->Kind == SK_Lambda;
904
16.3M
  }
905
906
  /// Is this scope known to be for a generic lambda? (This will be false until
907
  /// we parse a template parameter list or the first 'auto'-typed parameter).
908
0
  bool isGenericLambda() const {
909
0
    return !TemplateParams.empty() || GLTemplateParameterList;
910
0
  }
911
912
  /// Add a variable that might potentially be captured by the
913
  /// lambda and therefore the enclosing lambdas.
914
  ///
915
  /// This is also used by enclosing lambda's to speculatively capture
916
  /// variables that nested lambda's - depending on their enclosing
917
  /// specialization - might need to capture.
918
  /// Consider:
919
  /// void f(int, int); <-- don't capture
920
  /// void f(const int&, double); <-- capture
921
  /// void foo() {
922
  ///   const int x = 10;
923
  ///   auto L = [=](auto a) { // capture 'x'
924
  ///      return [=](auto b) {
925
  ///        f(x, a);  // we may or may not need to capture 'x'
926
  ///      };
927
  ///   };
928
  /// }
929
920
  void addPotentialCapture(Expr *VarExpr) {
930
920
    assert(isa<DeclRefExpr>(VarExpr) || isa<MemberExpr>(VarExpr) ||
931
920
           isa<FunctionParmPackExpr>(VarExpr));
932
920
    PotentiallyCapturingExprs.push_back(VarExpr);
933
920
  }
934
935
76
  void addPotentialThisCapture(SourceLocation Loc) {
936
76
    PotentialThisCaptureLocation = Loc;
937
76
  }
938
939
813
  bool hasPotentialThisCapture() const {
940
813
    return PotentialThisCaptureLocation.isValid();
941
813
  }
942
943
  /// Mark a variable's reference in a lambda as non-odr using.
944
  ///
945
  /// For generic lambdas, if a variable is named in a potentially evaluated
946
  /// expression, where the enclosing full expression is dependent then we
947
  /// must capture the variable (given a default capture).
948
  /// This is accomplished by recording all references to variables
949
  /// (DeclRefExprs or MemberExprs) within said nested lambda in its array of
950
  /// PotentialCaptures. All such variables have to be captured by that lambda,
951
  /// except for as described below.
952
  /// If that variable is usable as a constant expression and is named in a
953
  /// manner that does not involve its odr-use (e.g. undergoes
954
  /// lvalue-to-rvalue conversion, or discarded) record that it is so. Upon the
955
  /// act of analyzing the enclosing full expression (ActOnFinishFullExpr)
956
  /// if we can determine that the full expression is not instantiation-
957
  /// dependent, then we can entirely avoid its capture.
958
  ///
959
  ///   const int n = 0;
960
  ///   [&] (auto x) {
961
  ///     (void)+n + x;
962
  ///   };
963
  /// Interestingly, this strategy would involve a capture of n, even though
964
  /// it's obviously not odr-used here, because the full-expression is
965
  /// instantiation-dependent.  It could be useful to avoid capturing such
966
  /// variables, even when they are referred to in an instantiation-dependent
967
  /// expression, if we can unambiguously determine that they shall never be
968
  /// odr-used.  This would involve removal of the variable-referring-expression
969
  /// from the array of PotentialCaptures during the lvalue-to-rvalue
970
  /// conversions.  But per the working draft N3797, (post-chicago 2013) we must
971
  /// capture such variables.
972
  /// Before anyone is tempted to implement a strategy for not-capturing 'n',
973
  /// consider the insightful warning in:
974
  ///    /cfe-commits/Week-of-Mon-20131104/092596.html
975
  /// "The problem is that the set of captures for a lambda is part of the ABI
976
  ///  (since lambda layout can be made visible through inline functions and the
977
  ///  like), and there are no guarantees as to which cases we'll manage to build
978
  ///  an lvalue-to-rvalue conversion in, when parsing a template -- some
979
  ///  seemingly harmless change elsewhere in Sema could cause us to start or stop
980
  ///  building such a node. So we need a rule that anyone can implement and get
981
  ///  exactly the same result".
982
455
  void markVariableExprAsNonODRUsed(Expr *CapturingVarExpr) {
983
455
    assert(isa<DeclRefExpr>(CapturingVarExpr) ||
984
455
           isa<MemberExpr>(CapturingVarExpr) ||
985
455
           isa<FunctionParmPackExpr>(CapturingVarExpr));
986
455
    NonODRUsedCapturingExprs.insert(CapturingVarExpr);
987
455
  }
988
944
  bool isVariableExprMarkedAsNonODRUsed(Expr *CapturingVarExpr) const {
989
944
    assert(isa<DeclRefExpr>(CapturingVarExpr) ||
990
944
           isa<MemberExpr>(CapturingVarExpr) ||
991
944
           isa<FunctionParmPackExpr>(CapturingVarExpr));
992
944
    return NonODRUsedCapturingExprs.count(CapturingVarExpr);
993
944
  }
994
0
  void removePotentialCapture(Expr *E) {
995
0
    PotentiallyCapturingExprs.erase(
996
0
        std::remove(PotentiallyCapturingExprs.begin(),
997
0
            PotentiallyCapturingExprs.end(), E),
998
0
        PotentiallyCapturingExprs.end());
999
0
  }
1000
813
  void clearPotentialCaptures() {
1001
813
    PotentiallyCapturingExprs.clear();
1002
813
    PotentialThisCaptureLocation = SourceLocation();
1003
813
  }
1004
31.7k
  unsigned getNumPotentialVariableCaptures() const {
1005
31.7k
    return PotentiallyCapturingExprs.size();
1006
31.7k
  }
1007
1008
31.7k
  bool hasPotentialCaptures() const {
1009
31.7k
    return getNumPotentialVariableCaptures() ||
1010
30.9k
                                  PotentialThisCaptureLocation.isValid();
1011
31.7k
  }
1012
1013
  void visitPotentialCaptures(
1014
      llvm::function_ref<void(VarDecl *, Expr *)> Callback) const;
1015
};
1016
1017
FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy()
1018
2.34M
    : Base(nullptr, false) {}
1019
1020
FunctionScopeInfo::WeakObjectProfileTy
1021
757k
FunctionScopeInfo::WeakObjectProfileTy::getSentinel() {
1022
757k
  FunctionScopeInfo::WeakObjectProfileTy Result;
1023
757k
  Result.Base.setInt(true);
1024
757k
  return Result;
1025
757k
}
1026
1027
template <typename ExprT>
1028
256
void FunctionScopeInfo::recordUseOfWeak(const ExprT *E, bool IsRead) {
1029
256
  assert(E);
1030
256
  WeakUseVector &Uses = WeakObjectUses[WeakObjectProfileTy(E)];
1031
256
  Uses.push_back(WeakUseTy(E, IsRead));
1032
256
}
void clang::sema::FunctionScopeInfo::recordUseOfWeak<clang::DeclRefExpr>(clang::DeclRefExpr const*, bool)
Line
Count
Source
1028
26
void FunctionScopeInfo::recordUseOfWeak(const ExprT *E, bool IsRead) {
1029
26
  assert(E);
1030
26
  WeakUseVector &Uses = WeakObjectUses[WeakObjectProfileTy(E)];
1031
26
  Uses.push_back(WeakUseTy(E, IsRead));
1032
26
}
void clang::sema::FunctionScopeInfo::recordUseOfWeak<clang::ObjCIvarRefExpr>(clang::ObjCIvarRefExpr const*, bool)
Line
Count
Source
1028
24
void FunctionScopeInfo::recordUseOfWeak(const ExprT *E, bool IsRead) {
1029
24
  assert(E);
1030
24
  WeakUseVector &Uses = WeakObjectUses[WeakObjectProfileTy(E)];
1031
24
  Uses.push_back(WeakUseTy(E, IsRead));
1032
24
}
void clang::sema::FunctionScopeInfo::recordUseOfWeak<clang::ObjCPropertyRefExpr>(clang::ObjCPropertyRefExpr const*, bool)
Line
Count
Source
1028
206
void FunctionScopeInfo::recordUseOfWeak(const ExprT *E, bool IsRead) {
1029
206
  assert(E);
1030
206
  WeakUseVector &Uses = WeakObjectUses[WeakObjectProfileTy(E)];
1031
206
  Uses.push_back(WeakUseTy(E, IsRead));
1032
206
}
1033
1034
inline void CapturingScopeInfo::addThisCapture(bool isNested,
1035
                                               SourceLocation Loc,
1036
                                               QualType CaptureType,
1037
11.4k
                                               bool ByCopy) {
1038
11.4k
  Captures.push_back(Capture(Capture::ThisCapture, isNested, Loc, CaptureType,
1039
11.4k
                             ByCopy, /*Invalid*/ false));
1040
11.4k
  CXXThisCaptureIndex = Captures.size();
1041
11.4k
}
1042
1043
} // namespace sema
1044
1045
} // namespace clang
1046
1047
#endif // LLVM_CLANG_SEMA_SCOPEINFO_H