Coverage Report

Created: 2019-07-24 05:18

/Users/buildslave/jenkins/workspace/clang-stage2-coverage-R/llvm/tools/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
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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"
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#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 "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"
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#include "llvm/ADT/SmallSet.h"
31
#include "llvm/ADT/SmallVector.h"
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#include "llvm/ADT/StringRef.h"
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#include "llvm/ADT/StringSwitch.h"
34
#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>
38
#include <cassert>
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#include <utility>
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namespace clang {
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43
class BlockDecl;
44
class CapturedDecl;
45
class CXXMethodDecl;
46
class CXXRecordDecl;
47
class ImplicitParamDecl;
48
class NamedDecl;
49
class ObjCIvarRefExpr;
50
class ObjCMessageExpr;
51
class ObjCPropertyDecl;
52
class ObjCPropertyRefExpr;
53
class ParmVarDecl;
54
class RecordDecl;
55
class ReturnStmt;
56
class Scope;
57
class Stmt;
58
class SwitchStmt;
59
class TemplateParameterList;
60
class TemplateTypeParmDecl;
61
class VarDecl;
62
63
namespace sema {
64
65
/// Contains information about the compound statement currently being
66
/// parsed.
67
class CompoundScopeInfo {
68
public:
69
  /// Whether this compound stamement contains `for' or `while' loops
70
  /// with empty bodies.
71
  bool HasEmptyLoopBodies = false;
72
73
  /// Whether this compound statement corresponds to a GNU statement
74
  /// expression.
75
  bool IsStmtExpr;
76
77
4.70M
  CompoundScopeInfo(bool IsStmtExpr) : IsStmtExpr(IsStmtExpr) {}
78
79
14.0k
  void setHasEmptyLoopBodies() {
80
14.0k
    HasEmptyLoopBodies = true;
81
14.0k
  }
82
};
83
84
class PossiblyUnreachableDiag {
85
public:
86
  PartialDiagnostic PD;
87
  SourceLocation Loc;
88
  llvm::TinyPtrVector<const Stmt*> Stmts;
89
90
  PossiblyUnreachableDiag(const PartialDiagnostic &PD, SourceLocation Loc,
91
                          ArrayRef<const Stmt *> Stmts)
92
66.1k
      : PD(PD), Loc(Loc), Stmts(Stmts) {}
93
};
94
95
/// Retains information about a function, method, or block that is
96
/// currently being parsed.
97
class FunctionScopeInfo {
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protected:
99
  enum ScopeKind {
100
    SK_Function,
101
    SK_Block,
102
    SK_Lambda,
103
    SK_CapturedRegion
104
  };
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106
public:
107
  /// What kind of scope we are describing.
108
  ScopeKind Kind : 3;
109
110
  /// Whether this function contains a VLA, \@try, try, C++
111
  /// initializer, or anything else that can't be jumped past.
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  bool HasBranchProtectedScope : 1;
113
114
  /// Whether this function contains any switches or direct gotos.
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  bool HasBranchIntoScope : 1;
116
117
  /// Whether this function contains any indirect gotos.
118
  bool HasIndirectGoto : 1;
119
120
  /// Whether a statement was dropped because it was invalid.
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  bool HasDroppedStmt : 1;
122
123
  /// True if current scope is for OpenMP declare reduction combiner.
124
  bool HasOMPDeclareReductionCombiner : 1;
125
126
  /// Whether there is a fallthrough statement in this function.
127
  bool HasFallthroughStmt : 1;
128
129
  /// Whether we make reference to a declaration that could be
130
  /// unavailable.
131
  bool HasPotentialAvailabilityViolations : 1;
132
133
  /// A flag that is set when parsing a method that must call super's
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  /// implementation, such as \c -dealloc, \c -finalize, or any method marked
135
  /// with \c __attribute__((objc_requires_super)).
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  bool ObjCShouldCallSuper : 1;
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138
  /// True when this is a method marked as a designated initializer.
139
  bool ObjCIsDesignatedInit : 1;
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141
  /// This starts true for a method marked as designated initializer and will
142
  /// be set to false if there is an invocation to a designated initializer of
143
  /// the super class.
144
  bool ObjCWarnForNoDesignatedInitChain : 1;
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146
  /// True when this is an initializer method not marked as a designated
147
  /// initializer within a class that has at least one initializer marked as a
148
  /// designated initializer.
149
  bool ObjCIsSecondaryInit : 1;
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151
  /// 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'.
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  bool ObjCWarnForNoInitDelegation : 1;
154
155
  /// 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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159
  /// An enumeration represeting the kind of the first coroutine statement
160
  /// in the function. One of co_return, co_await, or co_yield.
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  unsigned char FirstCoroutineStmtKind : 2;
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  /// First coroutine statement in the current function.
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  /// (ex co_return, co_await, co_yield)
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  SourceLocation FirstCoroutineStmtLoc;
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  /// First 'return' statement in the current function.
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  SourceLocation FirstReturnLoc;
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  /// First C++ 'try' statement in the current function.
171
  SourceLocation FirstCXXTryLoc;
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  /// First SEH '__try' statement in the current function.
174
  SourceLocation FirstSEHTryLoc;
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176
  /// Used to determine if errors occurred in this function or block.
177
  DiagnosticErrorTrap ErrorTrap;
178
179
  /// A SwitchStmt, along with a flag indicating if its list of case statements
180
  /// is incomplete (because we dropped an invalid one while parsing).
181
  using SwitchInfo = llvm::PointerIntPair<SwitchStmt*, 1, bool>;
182
183
  /// SwitchStack - This is the current set of active switch statements in the
184
  /// block.
185
  SmallVector<SwitchInfo, 8> SwitchStack;
186
187
  /// The list of return statements that occur within the function or
188
  /// block, if there is any chance of applying the named return value
189
  /// optimization, or if we need to infer a return type.
190
  SmallVector<ReturnStmt*, 4> Returns;
191
192
  /// The promise object for this coroutine, if any.
193
  VarDecl *CoroutinePromise = nullptr;
194
195
  /// A mapping between the coroutine function parameters that were moved
196
  /// to the coroutine frame, and their move statements.
197
  llvm::SmallMapVector<ParmVarDecl *, Stmt *, 4> CoroutineParameterMoves;
198
199
  /// The initial and final coroutine suspend points.
200
  std::pair<Stmt *, Stmt *> CoroutineSuspends;
201
202
  /// The stack of currently active compound stamement scopes in the
203
  /// function.
204
  SmallVector<CompoundScopeInfo, 4> CompoundScopes;
205
206
  /// The set of blocks that are introduced in this function.
207
  llvm::SmallPtrSet<const BlockDecl *, 1> Blocks;
208
209
  /// The set of __block variables that are introduced in this function.
210
  llvm::TinyPtrVector<VarDecl *> ByrefBlockVars;
211
212
  /// A list of PartialDiagnostics created but delayed within the
213
  /// current function scope.  These diagnostics are vetted for reachability
214
  /// prior to being emitted.
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  SmallVector<PossiblyUnreachableDiag, 4> PossiblyUnreachableDiags;
216
217
  /// A list of parameters which have the nonnull attribute and are
218
  /// modified in the function.
219
  llvm::SmallPtrSet<const ParmVarDecl *, 8> ModifiedNonNullParams;
220
221
public:
222
  /// Represents a simple identification of a weak object.
223
  ///
224
  /// Part of the implementation of -Wrepeated-use-of-weak.
225
  ///
226
  /// This is used to determine if two weak accesses refer to the same object.
227
  /// Here are some examples of how various accesses are "profiled":
228
  ///
229
  /// Access Expression |     "Base" Decl     |          "Property" Decl
230
  /// :---------------: | :-----------------: | :------------------------------:
231
  /// self.property     | self (VarDecl)      | property (ObjCPropertyDecl)
232
  /// self.implicitProp | self (VarDecl)      | -implicitProp (ObjCMethodDecl)
233
  /// self->ivar.prop   | ivar (ObjCIvarDecl) | prop (ObjCPropertyDecl)
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  /// cxxObj.obj.prop   | obj (FieldDecl)     | prop (ObjCPropertyDecl)
235
  /// [self foo].prop   | 0 (unknown)         | prop (ObjCPropertyDecl)
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  /// self.prop1.prop2  | prop1 (ObjCPropertyDecl)    | prop2 (ObjCPropertyDecl)
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  /// MyClass.prop      | MyClass (ObjCInterfaceDecl) | -prop (ObjCMethodDecl)
238
  /// MyClass.foo.prop  | +foo (ObjCMethodDecl)       | -prop (ObjCPropertyDecl)
239
  /// weakVar           | 0 (known)           | weakVar (VarDecl)
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  /// self->weakIvar    | self (VarDecl)      | weakIvar (ObjCIvarDecl)
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  ///
242
  /// Objects are identified with only two Decls to make it reasonably fast to
243
  /// compare them.
244
  class WeakObjectProfileTy {
245
    /// The base object decl, as described in the class documentation.
246
    ///
247
    /// The extra flag is "true" if the Base and Property are enough to uniquely
248
    /// identify the object in memory.
249
    ///
250
    /// \sa isExactProfile()
251
    using BaseInfoTy = llvm::PointerIntPair<const NamedDecl *, 1, bool>;
252
    BaseInfoTy Base;
253
254
    /// The "property" decl, as described in the class documentation.
255
    ///
256
    /// Note that this may not actually be an ObjCPropertyDecl, e.g. in the
257
    /// case of "implicit" properties (regular methods accessed via dot syntax).
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    const NamedDecl *Property = nullptr;
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260
    /// Used to find the proper base profile for a given base expression.
261
    static BaseInfoTy getBaseInfo(const Expr *BaseE);
262
263
    inline WeakObjectProfileTy();
264
    static inline WeakObjectProfileTy getSentinel();
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266
  public:
267
    WeakObjectProfileTy(const ObjCPropertyRefExpr *RE);
268
    WeakObjectProfileTy(const Expr *Base, const ObjCPropertyDecl *Property);
269
    WeakObjectProfileTy(const DeclRefExpr *RE);
270
    WeakObjectProfileTy(const ObjCIvarRefExpr *RE);
271
272
18
    const NamedDecl *getBase() const { return Base.getPointer(); }
273
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    const NamedDecl *getProperty() const { return Property; }
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275
    /// Returns true if the object base specifies a known object in memory,
276
    /// rather than, say, an instance variable or property of another object.
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    ///
278
    /// Note that this ignores the effects of aliasing; that is, \c foo.bar is
279
    /// considered an exact profile if \c foo is a local variable, even if
280
    /// another variable \c foo2 refers to the same object as \c foo.
281
    ///
282
    /// For increased precision, accesses with base variables that are
283
    /// properties or ivars of 'self' (e.g. self.prop1.prop2) are considered to
284
    /// be exact, though this is not true for arbitrary variables
285
    /// (foo.prop1.prop2).
286
102
    bool isExactProfile() const {
287
102
      return Base.getInt();
288
102
    }
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290
3.83M
    bool operator==(const WeakObjectProfileTy &Other) const {
291
3.83M
      return Base == Other.Base && 
Property == Other.Property3.83M
;
292
3.83M
    }
293
294
    // For use in DenseMap.
295
    // We can't specialize the usual llvm::DenseMapInfo at the end of the file
296
    // because by that point the DenseMap in FunctionScopeInfo has already been
297
    // instantiated.
298
    class DenseMapInfo {
299
    public:
300
998k
      static inline WeakObjectProfileTy getEmptyKey() {
301
998k
        return WeakObjectProfileTy();
302
998k
      }
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304
472k
      static inline WeakObjectProfileTy getTombstoneKey() {
305
472k
        return WeakObjectProfileTy::getSentinel();
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472k
      }
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308
344
      static unsigned getHashValue(const WeakObjectProfileTy &Val) {
309
344
        using Pair = std::pair<BaseInfoTy, const NamedDecl *>;
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344
311
344
        return llvm::DenseMapInfo<Pair>::getHashValue(Pair(Val.Base,
312
344
                                                           Val.Property));
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344
      }
314
315
      static bool isEqual(const WeakObjectProfileTy &LHS,
316
3.83M
                          const WeakObjectProfileTy &RHS) {
317
3.83M
        return LHS == RHS;
318
3.83M
      }
319
    };
320
  };
321
322
  /// Represents a single use of a weak object.
323
  ///
324
  /// Stores both the expression and whether the access is potentially unsafe
325
  /// (i.e. it could potentially be warned about).
326
  ///
327
  /// Part of the implementation of -Wrepeated-use-of-weak.
328
  class WeakUseTy {
329
    llvm::PointerIntPair<const Expr *, 1, bool> Rep;
330
331
  public:
332
324
    WeakUseTy(const Expr *Use, bool IsRead) : Rep(Use, IsRead) {}
333
334
486
    const Expr *getUseExpr() const { return Rep.getPointer(); }
335
270
    bool isUnsafe() const { return Rep.getInt(); }
336
44
    void markSafe() { Rep.setInt(false); }
337
338
50
    bool operator==(const WeakUseTy &Other) const {
339
50
      return Rep == Other.Rep;
340
50
    }
341
  };
342
343
  /// Used to collect uses of a particular weak object in a function body.
344
  ///
345
  /// Part of the implementation of -Wrepeated-use-of-weak.
346
  using WeakUseVector = SmallVector<WeakUseTy, 4>;
347
348
  /// Used to collect all uses of weak objects in a function body.
349
  ///
350
  /// Part of the implementation of -Wrepeated-use-of-weak.
351
  using WeakObjectUseMap =
352
      llvm::SmallDenseMap<WeakObjectProfileTy, WeakUseVector, 8,
353
                          WeakObjectProfileTy::DenseMapInfo>;
354
355
private:
356
  /// Used to collect all uses of weak objects in this function body.
357
  ///
358
  /// Part of the implementation of -Wrepeated-use-of-weak.
359
  WeakObjectUseMap WeakObjectUses;
360
361
protected:
362
6.71k
  FunctionScopeInfo(const FunctionScopeInfo&) = default;
363
364
public:
365
  FunctionScopeInfo(DiagnosticsEngine &Diag)
366
      : Kind(SK_Function), HasBranchProtectedScope(false),
367
        HasBranchIntoScope(false), HasIndirectGoto(false),
368
        HasDroppedStmt(false), HasOMPDeclareReductionCombiner(false),
369
        HasFallthroughStmt(false), HasPotentialAvailabilityViolations(false),
370
        ObjCShouldCallSuper(false), ObjCIsDesignatedInit(false),
371
        ObjCWarnForNoDesignatedInitChain(false), ObjCIsSecondaryInit(false),
372
        ObjCWarnForNoInitDelegation(false), NeedsCoroutineSuspends(true),
373
465k
        ErrorTrap(Diag) {}
374
375
  virtual ~FunctionScopeInfo();
376
377
  /// Record that a weak object was accessed.
378
  ///
379
  /// Part of the implementation of -Wrepeated-use-of-weak.
380
  template <typename ExprT>
381
  inline void recordUseOfWeak(const ExprT *E, bool IsRead = true);
382
383
  void recordUseOfWeak(const ObjCMessageExpr *Msg,
384
                       const ObjCPropertyDecl *Prop);
385
386
  /// Record that a given expression is a "safe" access of a weak object (e.g.
387
  /// assigning it to a strong variable.)
388
  ///
389
  /// Part of the implementation of -Wrepeated-use-of-weak.
390
  void markSafeWeakUse(const Expr *E);
391
392
111
  const WeakObjectUseMap &getWeakObjectUses() const {
393
111
    return WeakObjectUses;
394
111
  }
395
396
23.5k
  void setHasBranchIntoScope() {
397
23.5k
    HasBranchIntoScope = true;
398
23.5k
  }
399
400
1.76M
  void setHasBranchProtectedScope() {
401
1.76M
    HasBranchProtectedScope = true;
402
1.76M
  }
403
404
143
  void setHasIndirectGoto() {
405
143
    HasIndirectGoto = true;
406
143
  }
407
408
0
  void setHasDroppedStmt() {
409
0
    HasDroppedStmt = true;
410
0
  }
411
412
632
  void setHasOMPDeclareReductionCombiner() {
413
632
    HasOMPDeclareReductionCombiner = true;
414
632
  }
415
416
881
  void setHasFallthroughStmt() {
417
881
    HasFallthroughStmt = true;
418
881
  }
419
420
11.6k
  void setHasCXXTry(SourceLocation TryLoc) {
421
11.6k
    setHasBranchProtectedScope();
422
11.6k
    FirstCXXTryLoc = TryLoc;
423
11.6k
  }
424
425
258
  void setHasSEHTry(SourceLocation TryLoc) {
426
258
    setHasBranchProtectedScope();
427
258
    FirstSEHTryLoc = TryLoc;
428
258
  }
429
430
3.54M
  bool NeedsScopeChecking() const {
431
3.54M
    return !HasDroppedStmt &&
432
3.54M
        (HasIndirectGoto ||
433
3.54M
          
(3.54M
HasBranchProtectedScope3.54M
&&
HasBranchIntoScope417k
));
434
3.54M
  }
435
436
  // Add a block introduced in this function.
437
2.62k
  void addBlock(const BlockDecl *BD) {
438
2.62k
    Blocks.insert(BD);
439
2.62k
  }
440
441
  // Add a __block variable introduced in this function.
442
255
  void addByrefBlockVar(VarDecl *VD) {
443
255
    ByrefBlockVars.push_back(VD);
444
255
  }
445
446
867k
  bool isCoroutine() const { return !FirstCoroutineStmtLoc.isInvalid(); }
447
448
260
  void setFirstCoroutineStmt(SourceLocation Loc, StringRef Keyword) {
449
260
    assert(FirstCoroutineStmtLoc.isInvalid() &&
450
260
                   "first coroutine statement location already set");
451
260
    FirstCoroutineStmtLoc = Loc;
452
260
    FirstCoroutineStmtKind = llvm::StringSwitch<unsigned char>(Keyword)
453
260
            .Case("co_return", 0)
454
260
            .Case("co_await", 1)
455
260
            .Case("co_yield", 2);
456
260
  }
457
458
19
  StringRef getFirstCoroutineStmtKeyword() const {
459
19
    assert(FirstCoroutineStmtLoc.isValid()
460
19
                   && "no coroutine statement available");
461
19
    switch (FirstCoroutineStmtKind) {
462
19
    
case 0: return "co_return"10
;
463
19
    
case 1: return "co_await"4
;
464
19
    
case 2: return "co_yield"5
;
465
19
    default:
466
0
      llvm_unreachable("FirstCoroutineStmtKind has an invalid value");
467
0
    };
468
0
  }
469
470
248
  void setNeedsCoroutineSuspends(bool value = true) {
471
248
    assert((!value || CoroutineSuspends.first == nullptr) &&
472
248
            "we already have valid suspend points");
473
248
    NeedsCoroutineSuspends = value;
474
248
  }
475
476
240
  bool hasInvalidCoroutineSuspends() const {
477
240
    return !NeedsCoroutineSuspends && CoroutineSuspends.first == nullptr;
478
240
  }
479
480
239
  void setCoroutineSuspends(Stmt *Initial, Stmt *Final) {
481
239
    assert(Initial && Final && "suspend points cannot be null");
482
239
    assert(CoroutineSuspends.first == nullptr && "suspend points already set");
483
239
    NeedsCoroutineSuspends = false;
484
239
    CoroutineSuspends.first = Initial;
485
239
    CoroutineSuspends.second = Final;
486
239
  }
487
488
  /// Clear out the information in this function scope, making it
489
  /// suitable for reuse.
490
  void Clear();
491
492
3.94M
  bool isPlainFunction() const { return Kind == SK_Function; }
493
};
494
495
class Capture {
496
  // There are three categories of capture: capturing 'this', capturing
497
  // local variables, and C++1y initialized captures (which can have an
498
  // arbitrary initializer, and don't really capture in the traditional
499
  // sense at all).
500
  //
501
  // There are three ways to capture a local variable:
502
  //  - capture by copy in the C++11 sense,
503
  //  - capture by reference in the C++11 sense, and
504
  //  - __block capture.
505
  // Lambdas explicitly specify capture by copy or capture by reference.
506
  // For blocks, __block capture applies to variables with that annotation,
507
  // variables of reference type are captured by reference, and other
508
  // variables are captured by copy.
509
  enum CaptureKind {
510
    Cap_ByCopy, Cap_ByRef, Cap_Block, Cap_VLA
511
  };
512
513
  union {
514
    /// If Kind == Cap_VLA, the captured type.
515
    const VariableArrayType *CapturedVLA;
516
517
    /// Otherwise, the captured variable (if any).
518
    VarDecl *CapturedVar;
519
  };
520
521
  /// The source location at which the first capture occurred.
522
  SourceLocation Loc;
523
524
  /// The location of the ellipsis that expands a parameter pack.
525
  SourceLocation EllipsisLoc;
526
527
  /// The type as it was captured, which is the type of the non-static data
528
  /// member that would hold the capture.
529
  QualType CaptureType;
530
531
  /// The CaptureKind of this capture.
532
  unsigned Kind : 2;
533
534
  /// Whether this is a nested capture (a capture of an enclosing capturing
535
  /// scope's capture).
536
  unsigned Nested : 1;
537
538
  /// Whether this is a capture of '*this'.
539
  unsigned CapturesThis : 1;
540
541
  /// Whether an explicit capture has been odr-used in the body of the
542
  /// lambda.
543
  unsigned ODRUsed : 1;
544
545
  /// Whether an explicit capture has been non-odr-used in the body of
546
  /// the lambda.
547
  unsigned NonODRUsed : 1;
548
549
  /// Whether the capture is invalid (a capture was required but the entity is
550
  /// non-capturable).
551
  unsigned Invalid : 1;
552
553
public:
554
  Capture(VarDecl *Var, bool Block, bool ByRef, bool IsNested,
555
          SourceLocation Loc, SourceLocation EllipsisLoc, QualType CaptureType,
556
          bool Invalid)
557
      : CapturedVar(Var), Loc(Loc), EllipsisLoc(EllipsisLoc),
558
        CaptureType(CaptureType),
559
        Kind(Block ? Cap_Block : ByRef ? Cap_ByRef : Cap_ByCopy),
560
        Nested(IsNested), CapturesThis(false), ODRUsed(false),
561
234k
        NonODRUsed(false), Invalid(Invalid) {}
562
563
  enum IsThisCapture { ThisCapture };
564
  Capture(IsThisCapture, bool IsNested, SourceLocation Loc,
565
          QualType CaptureType, const bool ByCopy, bool Invalid)
566
      : Loc(Loc), CaptureType(CaptureType),
567
        Kind(ByCopy ? Cap_ByCopy : Cap_ByRef), Nested(IsNested),
568
        CapturesThis(true), ODRUsed(false), NonODRUsed(false),
569
8.19k
        Invalid(Invalid) {}
570
571
  enum IsVLACapture { VLACapture };
572
  Capture(IsVLACapture, const VariableArrayType *VLA, bool IsNested,
573
          SourceLocation Loc, QualType CaptureType)
574
      : CapturedVLA(VLA), Loc(Loc), CaptureType(CaptureType), Kind(Cap_VLA),
575
        Nested(IsNested), CapturesThis(false), ODRUsed(false),
576
5.58k
        NonODRUsed(false), Invalid(false) {}
577
578
772k
  bool isThisCapture() const { return CapturesThis; }
579
315k
  bool isVariableCapture() const {
580
315k
    return !isThisCapture() && 
!isVLATypeCapture()303k
;
581
315k
  }
582
583
593k
  bool isCopyCapture() const { return Kind == Cap_ByCopy; }
584
211k
  bool isReferenceCapture() const { return Kind == Cap_ByRef; }
585
2.87k
  bool isBlockCapture() const { return Kind == Cap_Block; }
586
1.03M
  bool isVLATypeCapture() const { return Kind == Cap_VLA; }
587
588
227k
  bool isNested() const { return Nested; }
589
590
232k
  bool isInvalid() const { return Invalid; }
591
592
  /// Determine whether this capture is an init-capture.
593
  bool isInitCapture() const;
594
595
1.14k
  bool isODRUsed() const { return ODRUsed; }
596
460
  bool isNonODRUsed() const { return NonODRUsed; }
597
584k
  void markUsed(bool IsODRUse) {
598
584k
    if (IsODRUse)
599
211k
      ODRUsed = true;
600
372k
    else
601
372k
      NonODRUsed = true;
602
584k
  }
603
604
945k
  VarDecl *getVariable() const {
605
945k
    assert(isVariableCapture());
606
945k
    return CapturedVar;
607
945k
  }
608
609
24.5k
  const VariableArrayType *getCapturedVLAType() const {
610
24.5k
    assert(isVLATypeCapture());
611
24.5k
    return CapturedVLA;
612
24.5k
  }
613
614
  /// Retrieve the location at which this variable was captured.
615
685k
  SourceLocation getLocation() const { return Loc; }
616
617
  /// Retrieve the source location of the ellipsis, whose presence
618
  /// indicates that the capture is a pack expansion.
619
4.61k
  SourceLocation getEllipsisLoc() const { return EllipsisLoc; }
620
621
  /// Retrieve the capture type for this capture, which is effectively
622
  /// the type of the non-static data member in the lambda/block structure
623
  /// that would store this capture.
624
812k
  QualType getCaptureType() const { return CaptureType; }
625
};
626
627
class CapturingScopeInfo : public FunctionScopeInfo {
628
protected:
629
6.71k
  CapturingScopeInfo(const CapturingScopeInfo&) = default;
630
631
public:
632
  enum ImplicitCaptureStyle {
633
    ImpCap_None, ImpCap_LambdaByval, ImpCap_LambdaByref, ImpCap_Block,
634
    ImpCap_CapturedRegion
635
  };
636
637
  ImplicitCaptureStyle ImpCaptureStyle;
638
639
  CapturingScopeInfo(DiagnosticsEngine &Diag, ImplicitCaptureStyle Style)
640
306k
      : FunctionScopeInfo(Diag), ImpCaptureStyle(Style) {}
641
642
  /// CaptureMap - A map of captured variables to (index+1) into Captures.
643
  llvm::DenseMap<VarDecl*, unsigned> CaptureMap;
644
645
  /// CXXThisCaptureIndex - The (index+1) of the capture of 'this';
646
  /// zero if 'this' is not captured.
647
  unsigned CXXThisCaptureIndex = 0;
648
649
  /// Captures - The captures.
650
  SmallVector<Capture, 4> Captures;
651
652
  /// - Whether the target type of return statements in this context
653
  /// is deduced (e.g. a lambda or block with omitted return type).
654
  bool HasImplicitReturnType = false;
655
656
  /// ReturnType - The target type of return statements in this context,
657
  /// or null if unknown.
658
  QualType ReturnType;
659
660
  void addCapture(VarDecl *Var, bool isBlock, bool isByref, bool isNested,
661
                  SourceLocation Loc, SourceLocation EllipsisLoc,
662
234k
                  QualType CaptureType, bool Invalid) {
663
234k
    Captures.push_back(Capture(Var, isBlock, isByref, isNested, Loc,
664
234k
                               EllipsisLoc, CaptureType, Invalid));
665
234k
    CaptureMap[Var] = Captures.size();
666
234k
  }
667
668
  void addVLATypeCapture(SourceLocation Loc, const VariableArrayType *VLAType,
669
5.58k
                         QualType CaptureType) {
670
5.58k
    Captures.push_back(Capture(Capture::VLACapture, VLAType,
671
5.58k
                               /*FIXME: IsNested*/ false, Loc, CaptureType));
672
5.58k
  }
673
674
  void addThisCapture(bool isNested, SourceLocation Loc, QualType CaptureType,
675
                      bool ByCopy);
676
677
  /// Determine whether the C++ 'this' is captured.
678
4.18k
  bool isCXXThisCaptured() const { return CXXThisCaptureIndex != 0; }
679
680
  /// Retrieve the capture of C++ 'this', if it has been captured.
681
2.30k
  Capture &getCXXThisCapture() {
682
2.30k
    assert(isCXXThisCaptured() && "this has not been captured");
683
2.30k
    return Captures[CXXThisCaptureIndex - 1];
684
2.30k
  }
685
686
  /// Determine whether the given variable has been captured.
687
153
  bool isCaptured(VarDecl *Var) const {
688
153
    return CaptureMap.count(Var);
689
153
  }
690
691
  /// Determine whether the given variable-array type has been captured.
692
  bool isVLATypeCaptured(const VariableArrayType *VAT) const;
693
694
  /// Retrieve the capture of the given variable, if it has been
695
  /// captured already.
696
1.72M
  Capture &getCapture(VarDecl *Var) {
697
1.72M
    assert(isCaptured(Var) && "Variable has not been captured");
698
1.72M
    return Captures[CaptureMap[Var] - 1];
699
1.72M
  }
700
701
0
  const Capture &getCapture(VarDecl *Var) const {
702
0
    llvm::DenseMap<VarDecl*, unsigned>::const_iterator Known
703
0
      = CaptureMap.find(Var);
704
0
    assert(Known != CaptureMap.end() && "Variable has not been captured");
705
0
    return Captures[Known->second - 1];
706
0
  }
707
708
18.5M
  static bool classof(const FunctionScopeInfo *FSI) {
709
18.5M
    return FSI->Kind == SK_Block || 
FSI->Kind == SK_Lambda18.5M
710
18.5M
                                 || 
FSI->Kind == SK_CapturedRegion18.5M
;
711
18.5M
  }
712
};
713
714
/// Retains information about a block that is currently being parsed.
715
class BlockScopeInfo final : public CapturingScopeInfo {
716
public:
717
  BlockDecl *TheDecl;
718
719
  /// TheScope - This is the scope for the block itself, which contains
720
  /// arguments etc.
721
  Scope *TheScope;
722
723
  /// BlockType - The function type of the block, if one was given.
724
  /// Its return type may be BuiltinType::Dependent.
725
  QualType FunctionType;
726
727
  BlockScopeInfo(DiagnosticsEngine &Diag, Scope *BlockScope, BlockDecl *Block)
728
      : CapturingScopeInfo(Diag, ImpCap_Block), TheDecl(Block),
729
2.75k
        TheScope(BlockScope) {
730
2.75k
    Kind = SK_Block;
731
2.75k
  }
732
733
  ~BlockScopeInfo() override;
734
735
1.69M
  static bool classof(const FunctionScopeInfo *FSI) {
736
1.69M
    return FSI->Kind == SK_Block;
737
1.69M
  }
738
};
739
740
/// Retains information about a captured region.
741
class CapturedRegionScopeInfo final : public CapturingScopeInfo {
742
public:
743
  /// The CapturedDecl for this statement.
744
  CapturedDecl *TheCapturedDecl;
745
746
  /// The captured record type.
747
  RecordDecl *TheRecordDecl;
748
749
  /// This is the enclosing scope of the captured region.
750
  Scope *TheScope;
751
752
  /// The implicit parameter for the captured variables.
753
  ImplicitParamDecl *ContextParam;
754
755
  /// The kind of captured region.
756
  unsigned short CapRegionKind;
757
758
  unsigned short OpenMPLevel;
759
760
  CapturedRegionScopeInfo(DiagnosticsEngine &Diag, Scope *S, CapturedDecl *CD,
761
                          RecordDecl *RD, ImplicitParamDecl *Context,
762
                          CapturedRegionKind K, unsigned OpenMPLevel)
763
      : CapturingScopeInfo(Diag, ImpCap_CapturedRegion),
764
        TheCapturedDecl(CD), TheRecordDecl(RD), TheScope(S),
765
295k
        ContextParam(Context), CapRegionKind(K), OpenMPLevel(OpenMPLevel) {
766
295k
    Kind = SK_CapturedRegion;
767
295k
  }
768
769
  ~CapturedRegionScopeInfo() override;
770
771
  /// A descriptive name for the kind of captured region this is.
772
125
  StringRef getRegionName() const {
773
125
    switch (CapRegionKind) {
774
125
    case CR_Default:
775
1
      return "default captured statement";
776
125
    case CR_ObjCAtFinally:
777
0
      return "Objective-C @finally statement";
778
125
    case CR_OpenMP:
779
124
      return "OpenMP region";
780
0
    }
781
0
    llvm_unreachable("Invalid captured region kind!");
782
0
  }
783
784
2.30M
  static bool classof(const FunctionScopeInfo *FSI) {
785
2.30M
    return FSI->Kind == SK_CapturedRegion;
786
2.30M
  }
787
};
788
789
class LambdaScopeInfo final : public CapturingScopeInfo {
790
public:
791
  /// The class that describes the lambda.
792
  CXXRecordDecl *Lambda = nullptr;
793
794
  /// The lambda's compiler-generated \c operator().
795
  CXXMethodDecl *CallOperator = nullptr;
796
797
  /// Source range covering the lambda introducer [...].
798
  SourceRange IntroducerRange;
799
800
  /// Source location of the '&' or '=' specifying the default capture
801
  /// type, if any.
802
  SourceLocation CaptureDefaultLoc;
803
804
  /// The number of captures in the \c Captures list that are
805
  /// explicit captures.
806
  unsigned NumExplicitCaptures = 0;
807
808
  /// Whether this is a mutable lambda.
809
  bool Mutable = false;
810
811
  /// Whether the (empty) parameter list is explicit.
812
  bool ExplicitParams = false;
813
814
  /// Whether any of the capture expressions requires cleanups.
815
  CleanupInfo Cleanup;
816
817
  /// Whether the lambda contains an unexpanded parameter pack.
818
  bool ContainsUnexpandedParameterPack = false;
819
820
  /// If this is a generic lambda, use this as the depth of
821
  /// each 'auto' parameter, during initial AST construction.
822
  unsigned AutoTemplateParameterDepth = 0;
823
824
  /// The number of parameters in the template parameter list that were
825
  /// explicitly specified by the user, as opposed to being invented by use
826
  /// of an auto parameter.
827
  unsigned NumExplicitTemplateParams = 0;
828
829
  /// Source range covering the explicit template parameter list (if it exists).
830
  SourceRange ExplicitTemplateParamsRange;
831
832
  /// Store the list of the template parameters for a generic lambda.
833
  /// If this is a generic lambda, this holds the explicit template parameters
834
  /// followed by the auto parameters converted into TemplateTypeParmDecls.
835
  /// It can be used to construct the generic lambda's template parameter list
836
  /// during initial AST construction.
837
  SmallVector<NamedDecl*, 4> TemplateParams;
838
839
  /// If this is a generic lambda, and the template parameter
840
  /// list has been created (from the TemplateParams) then store
841
  /// a reference to it (cache it to avoid reconstructing it).
842
  TemplateParameterList *GLTemplateParameterList = nullptr;
843
844
  /// Contains all variable-referring-expressions (i.e. DeclRefExprs
845
  ///  or MemberExprs) that refer to local variables in a generic lambda
846
  ///  or a lambda in a potentially-evaluated-if-used context.
847
  ///
848
  ///  Potentially capturable variables of a nested lambda that might need
849
  ///   to be captured by the lambda are housed here.
850
  ///  This is specifically useful for generic lambdas or
851
  ///  lambdas within a potentially evaluated-if-used context.
852
  ///  If an enclosing variable is named in an expression of a lambda nested
853
  ///  within a generic lambda, we don't always know know whether the variable
854
  ///  will truly be odr-used (i.e. need to be captured) by that nested lambda,
855
  ///  until its instantiation. But we still need to capture it in the
856
  ///  enclosing lambda if all intervening lambdas can capture the variable.
857
  llvm::SmallVector<Expr*, 4> PotentiallyCapturingExprs;
858
859
  /// Contains all variable-referring-expressions that refer
860
  ///  to local variables that are usable as constant expressions and
861
  ///  do not involve an odr-use (they may still need to be captured
862
  ///  if the enclosing full-expression is instantiation dependent).
863
  llvm::SmallSet<Expr *, 8> NonODRUsedCapturingExprs;
864
865
  /// A map of explicit capture indices to their introducer source ranges.
866
  llvm::DenseMap<unsigned, SourceRange> ExplicitCaptureRanges;
867
868
  /// Contains all of the variables defined in this lambda that shadow variables
869
  /// that were defined in parent contexts. Used to avoid warnings when the
870
  /// shadowed variables are uncaptured by this lambda.
871
  struct ShadowedOuterDecl {
872
    const VarDecl *VD;
873
    const VarDecl *ShadowedDecl;
874
  };
875
  llvm::SmallVector<ShadowedOuterDecl, 4> ShadowingDecls;
876
877
  SourceLocation PotentialThisCaptureLocation;
878
879
  LambdaScopeInfo(DiagnosticsEngine &Diag)
880
7.99k
      : CapturingScopeInfo(Diag, ImpCap_None) {
881
7.99k
    Kind = SK_Lambda;
882
7.99k
  }
883
884
  /// Note when all explicit captures have been added.
885
6.75k
  void finishedExplicitCaptures() {
886
6.75k
    NumExplicitCaptures = Captures.size();
887
6.75k
  }
888
889
15.1M
  static bool classof(const FunctionScopeInfo *FSI) {
890
15.1M
    return FSI->Kind == SK_Lambda;
891
15.1M
  }
892
893
  /// Is this scope known to be for a generic lambda? (This will be false until
894
  /// we parse a template parameter list or the first 'auto'-typed parameter).
895
0
  bool isGenericLambda() const {
896
0
    return !TemplateParams.empty() || GLTemplateParameterList;
897
0
  }
898
899
  /// Add a variable that might potentially be captured by the
900
  /// lambda and therefore the enclosing lambdas.
901
  ///
902
  /// This is also used by enclosing lambda's to speculatively capture
903
  /// variables that nested lambda's - depending on their enclosing
904
  /// specialization - might need to capture.
905
  /// Consider:
906
  /// void f(int, int); <-- don't capture
907
  /// void f(const int&, double); <-- capture
908
  /// void foo() {
909
  ///   const int x = 10;
910
  ///   auto L = [=](auto a) { // capture 'x'
911
  ///      return [=](auto b) {
912
  ///        f(x, a);  // we may or may not need to capture 'x'
913
  ///      };
914
  ///   };
915
  /// }
916
733
  void addPotentialCapture(Expr *VarExpr) {
917
733
    assert(isa<DeclRefExpr>(VarExpr) || isa<MemberExpr>(VarExpr) ||
918
733
           isa<FunctionParmPackExpr>(VarExpr));
919
733
    PotentiallyCapturingExprs.push_back(VarExpr);
920
733
  }
921
922
38
  void addPotentialThisCapture(SourceLocation Loc) {
923
38
    PotentialThisCaptureLocation = Loc;
924
38
  }
925
926
597
  bool hasPotentialThisCapture() const {
927
597
    return PotentialThisCaptureLocation.isValid();
928
597
  }
929
930
  /// Mark a variable's reference in a lambda as non-odr using.
931
  ///
932
  /// For generic lambdas, if a variable is named in a potentially evaluated
933
  /// expression, where the enclosing full expression is dependent then we
934
  /// must capture the variable (given a default capture).
935
  /// This is accomplished by recording all references to variables
936
  /// (DeclRefExprs or MemberExprs) within said nested lambda in its array of
937
  /// PotentialCaptures. All such variables have to be captured by that lambda,
938
  /// except for as described below.
939
  /// If that variable is usable as a constant expression and is named in a
940
  /// manner that does not involve its odr-use (e.g. undergoes
941
  /// lvalue-to-rvalue conversion, or discarded) record that it is so. Upon the
942
  /// act of analyzing the enclosing full expression (ActOnFinishFullExpr)
943
  /// if we can determine that the full expression is not instantiation-
944
  /// dependent, then we can entirely avoid its capture.
945
  ///
946
  ///   const int n = 0;
947
  ///   [&] (auto x) {
948
  ///     (void)+n + x;
949
  ///   };
950
  /// Interestingly, this strategy would involve a capture of n, even though
951
  /// it's obviously not odr-used here, because the full-expression is
952
  /// instantiation-dependent.  It could be useful to avoid capturing such
953
  /// variables, even when they are referred to in an instantiation-dependent
954
  /// expression, if we can unambiguously determine that they shall never be
955
  /// odr-used.  This would involve removal of the variable-referring-expression
956
  /// from the array of PotentialCaptures during the lvalue-to-rvalue
957
  /// conversions.  But per the working draft N3797, (post-chicago 2013) we must
958
  /// capture such variables.
959
  /// Before anyone is tempted to implement a strategy for not-capturing 'n',
960
  /// consider the insightful warning in:
961
  ///    /cfe-commits/Week-of-Mon-20131104/092596.html
962
  /// "The problem is that the set of captures for a lambda is part of the ABI
963
  ///  (since lambda layout can be made visible through inline functions and the
964
  ///  like), and there are no guarantees as to which cases we'll manage to build
965
  ///  an lvalue-to-rvalue conversion in, when parsing a template -- some
966
  ///  seemingly harmless change elsewhere in Sema could cause us to start or stop
967
  ///  building such a node. So we need a rule that anyone can implement and get
968
  ///  exactly the same result".
969
582
  void markVariableExprAsNonODRUsed(Expr *CapturingVarExpr) {
970
582
    assert(isa<DeclRefExpr>(CapturingVarExpr) ||
971
582
           isa<MemberExpr>(CapturingVarExpr) ||
972
582
           isa<FunctionParmPackExpr>(CapturingVarExpr));
973
582
    NonODRUsedCapturingExprs.insert(CapturingVarExpr);
974
582
  }
975
746
  bool isVariableExprMarkedAsNonODRUsed(Expr *CapturingVarExpr) const {
976
746
    assert(isa<DeclRefExpr>(CapturingVarExpr) ||
977
746
           isa<MemberExpr>(CapturingVarExpr) ||
978
746
           isa<FunctionParmPackExpr>(CapturingVarExpr));
979
746
    return NonODRUsedCapturingExprs.count(CapturingVarExpr);
980
746
  }
981
0
  void removePotentialCapture(Expr *E) {
982
0
    PotentiallyCapturingExprs.erase(
983
0
        std::remove(PotentiallyCapturingExprs.begin(),
984
0
            PotentiallyCapturingExprs.end(), E),
985
0
        PotentiallyCapturingExprs.end());
986
0
  }
987
597
  void clearPotentialCaptures() {
988
597
    PotentiallyCapturingExprs.clear();
989
597
    PotentialThisCaptureLocation = SourceLocation();
990
597
  }
991
25.0k
  unsigned getNumPotentialVariableCaptures() const {
992
25.0k
    return PotentiallyCapturingExprs.size();
993
25.0k
  }
994
995
25.0k
  bool hasPotentialCaptures() const {
996
25.0k
    return getNumPotentialVariableCaptures() ||
997
25.0k
                                  
PotentialThisCaptureLocation.isValid()24.5k
;
998
25.0k
  }
999
1000
  void visitPotentialCaptures(
1001
      llvm::function_ref<void(VarDecl *, Expr *)> Callback) const;
1002
};
1003
1004
FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy()
1005
1.47M
    : Base(nullptr, false) {}
1006
1007
FunctionScopeInfo::WeakObjectProfileTy
1008
472k
FunctionScopeInfo::WeakObjectProfileTy::getSentinel() {
1009
472k
  FunctionScopeInfo::WeakObjectProfileTy Result;
1010
472k
  Result.Base.setInt(true);
1011
472k
  return Result;
1012
472k
}
1013
1014
template <typename ExprT>
1015
254
void FunctionScopeInfo::recordUseOfWeak(const ExprT *E, bool IsRead) {
1016
254
  assert(E);
1017
254
  WeakUseVector &Uses = WeakObjectUses[WeakObjectProfileTy(E)];
1018
254
  Uses.push_back(WeakUseTy(E, IsRead));
1019
254
}
void clang::sema::FunctionScopeInfo::recordUseOfWeak<clang::DeclRefExpr>(clang::DeclRefExpr const*, bool)
Line
Count
Source
1015
26
void FunctionScopeInfo::recordUseOfWeak(const ExprT *E, bool IsRead) {
1016
26
  assert(E);
1017
26
  WeakUseVector &Uses = WeakObjectUses[WeakObjectProfileTy(E)];
1018
26
  Uses.push_back(WeakUseTy(E, IsRead));
1019
26
}
void clang::sema::FunctionScopeInfo::recordUseOfWeak<clang::ObjCIvarRefExpr>(clang::ObjCIvarRefExpr const*, bool)
Line
Count
Source
1015
24
void FunctionScopeInfo::recordUseOfWeak(const ExprT *E, bool IsRead) {
1016
24
  assert(E);
1017
24
  WeakUseVector &Uses = WeakObjectUses[WeakObjectProfileTy(E)];
1018
24
  Uses.push_back(WeakUseTy(E, IsRead));
1019
24
}
void clang::sema::FunctionScopeInfo::recordUseOfWeak<clang::ObjCPropertyRefExpr>(clang::ObjCPropertyRefExpr const*, bool)
Line
Count
Source
1015
204
void FunctionScopeInfo::recordUseOfWeak(const ExprT *E, bool IsRead) {
1016
204
  assert(E);
1017
204
  WeakUseVector &Uses = WeakObjectUses[WeakObjectProfileTy(E)];
1018
204
  Uses.push_back(WeakUseTy(E, IsRead));
1019
204
}
1020
1021
inline void CapturingScopeInfo::addThisCapture(bool isNested,
1022
                                               SourceLocation Loc,
1023
                                               QualType CaptureType,
1024
8.19k
                                               bool ByCopy) {
1025
8.19k
  Captures.push_back(Capture(Capture::ThisCapture, isNested, Loc, CaptureType,
1026
8.19k
                             ByCopy, /*Invalid*/ false));
1027
8.19k
  CXXThisCaptureIndex = Captures.size();
1028
8.19k
}
1029
1030
} // namespace sema
1031
1032
} // namespace clang
1033
1034
#endif // LLVM_CLANG_SEMA_SCOPEINFO_H