clang  10.0.0svn
ScopeInfo.cpp
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1 //===--- ScopeInfo.cpp - Information about a semantic context -------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file implements FunctionScopeInfo and its subclasses, which contain
10 // information about a single function, block, lambda, or method body.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "clang/Sema/ScopeInfo.h"
15 #include "clang/AST/Decl.h"
16 #include "clang/AST/DeclCXX.h"
17 #include "clang/AST/DeclObjC.h"
18 #include "clang/AST/Expr.h"
19 #include "clang/AST/ExprCXX.h"
20 #include "clang/AST/ExprObjC.h"
21 
22 using namespace clang;
23 using namespace sema;
24 
27  HasBranchIntoScope = false;
28  HasIndirectGoto = false;
29  HasDroppedStmt = false;
31  HasFallthroughStmt = false;
33  ObjCShouldCallSuper = false;
34  ObjCIsDesignatedInit = false;
36  ObjCIsSecondaryInit = false;
41 
42  // Coroutine state
44  CoroutinePromise = nullptr;
47  CoroutineSuspends.first = nullptr;
48  CoroutineSuspends.second = nullptr;
49 
50  SwitchStack.clear();
51  Returns.clear();
52  ErrorTrap.reset();
54  WeakObjectUses.clear();
55  ModifiedNonNullParams.clear();
56  Blocks.clear();
57  ByrefBlockVars.clear();
58 }
59 
60 static const NamedDecl *getBestPropertyDecl(const ObjCPropertyRefExpr *PropE) {
61  if (PropE->isExplicitProperty())
62  return PropE->getExplicitProperty();
63 
64  return PropE->getImplicitPropertyGetter();
65 }
66 
67 FunctionScopeInfo::WeakObjectProfileTy::BaseInfoTy
68 FunctionScopeInfo::WeakObjectProfileTy::getBaseInfo(const Expr *E) {
69  E = E->IgnoreParenCasts();
70 
71  const NamedDecl *D = nullptr;
72  bool IsExact = false;
73 
74  switch (E->getStmtClass()) {
75  case Stmt::DeclRefExprClass:
76  D = cast<DeclRefExpr>(E)->getDecl();
77  IsExact = isa<VarDecl>(D);
78  break;
79  case Stmt::MemberExprClass: {
80  const MemberExpr *ME = cast<MemberExpr>(E);
81  D = ME->getMemberDecl();
82  IsExact = isa<CXXThisExpr>(ME->getBase()->IgnoreParenImpCasts());
83  break;
84  }
85  case Stmt::ObjCIvarRefExprClass: {
86  const ObjCIvarRefExpr *IE = cast<ObjCIvarRefExpr>(E);
87  D = IE->getDecl();
88  IsExact = IE->getBase()->isObjCSelfExpr();
89  break;
90  }
91  case Stmt::PseudoObjectExprClass: {
92  const PseudoObjectExpr *POE = cast<PseudoObjectExpr>(E);
93  const ObjCPropertyRefExpr *BaseProp =
94  dyn_cast<ObjCPropertyRefExpr>(POE->getSyntacticForm());
95  if (BaseProp) {
96  D = getBestPropertyDecl(BaseProp);
97 
98  if (BaseProp->isObjectReceiver()) {
99  const Expr *DoubleBase = BaseProp->getBase();
100  if (const OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(DoubleBase))
101  DoubleBase = OVE->getSourceExpr();
102 
103  IsExact = DoubleBase->isObjCSelfExpr();
104  }
105  }
106  break;
107  }
108  default:
109  break;
110  }
111 
112  return BaseInfoTy(D, IsExact);
113 }
114 
115 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(
116  const ObjCPropertyRefExpr *PropE)
117  : Base(nullptr, true), Property(getBestPropertyDecl(PropE)) {
118 
119  if (PropE->isObjectReceiver()) {
120  const OpaqueValueExpr *OVE = cast<OpaqueValueExpr>(PropE->getBase());
121  const Expr *E = OVE->getSourceExpr();
122  Base = getBaseInfo(E);
123  } else if (PropE->isClassReceiver()) {
124  Base.setPointer(PropE->getClassReceiver());
125  } else {
126  assert(PropE->isSuperReceiver());
127  }
128 }
129 
130 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(const Expr *BaseE,
131  const ObjCPropertyDecl *Prop)
132  : Base(nullptr, true), Property(Prop) {
133  if (BaseE)
134  Base = getBaseInfo(BaseE);
135  // else, this is a message accessing a property on super.
136 }
137 
138 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(
139  const DeclRefExpr *DRE)
140  : Base(nullptr, true), Property(DRE->getDecl()) {
141  assert(isa<VarDecl>(Property));
142 }
143 
144 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(
145  const ObjCIvarRefExpr *IvarE)
146  : Base(getBaseInfo(IvarE->getBase())), Property(IvarE->getDecl()) {
147 }
148 
150  const ObjCPropertyDecl *Prop) {
151  assert(Msg && Prop);
152  WeakUseVector &Uses =
153  WeakObjectUses[WeakObjectProfileTy(Msg->getInstanceReceiver(), Prop)];
154  Uses.push_back(WeakUseTy(Msg, Msg->getNumArgs() == 0));
155 }
156 
158  E = E->IgnoreParenCasts();
159 
160  if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(E)) {
161  markSafeWeakUse(POE->getSyntacticForm());
162  return;
163  }
164 
165  if (const ConditionalOperator *Cond = dyn_cast<ConditionalOperator>(E)) {
166  markSafeWeakUse(Cond->getTrueExpr());
167  markSafeWeakUse(Cond->getFalseExpr());
168  return;
169  }
170 
171  if (const BinaryConditionalOperator *Cond =
172  dyn_cast<BinaryConditionalOperator>(E)) {
173  markSafeWeakUse(Cond->getCommon());
174  markSafeWeakUse(Cond->getFalseExpr());
175  return;
176  }
177 
178  // Has this weak object been seen before?
179  FunctionScopeInfo::WeakObjectUseMap::iterator Uses = WeakObjectUses.end();
180  if (const ObjCPropertyRefExpr *RefExpr = dyn_cast<ObjCPropertyRefExpr>(E)) {
181  if (!RefExpr->isObjectReceiver())
182  return;
183  if (isa<OpaqueValueExpr>(RefExpr->getBase()))
184  Uses = WeakObjectUses.find(WeakObjectProfileTy(RefExpr));
185  else {
186  markSafeWeakUse(RefExpr->getBase());
187  return;
188  }
189  }
190  else if (const ObjCIvarRefExpr *IvarE = dyn_cast<ObjCIvarRefExpr>(E))
191  Uses = WeakObjectUses.find(WeakObjectProfileTy(IvarE));
192  else if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
193  if (isa<VarDecl>(DRE->getDecl()))
194  Uses = WeakObjectUses.find(WeakObjectProfileTy(DRE));
195  } else if (const ObjCMessageExpr *MsgE = dyn_cast<ObjCMessageExpr>(E)) {
196  if (const ObjCMethodDecl *MD = MsgE->getMethodDecl()) {
197  if (const ObjCPropertyDecl *Prop = MD->findPropertyDecl()) {
198  Uses =
199  WeakObjectUses.find(WeakObjectProfileTy(MsgE->getInstanceReceiver(),
200  Prop));
201  }
202  }
203  }
204  else
205  return;
206 
207  if (Uses == WeakObjectUses.end())
208  return;
209 
210  // Has there been a read from the object using this Expr?
211  FunctionScopeInfo::WeakUseVector::reverse_iterator ThisUse =
212  llvm::find(llvm::reverse(Uses->second), WeakUseTy(E, true));
213  if (ThisUse == Uses->second.rend())
214  return;
215 
216  ThisUse->markSafe();
217 }
218 
220  // Note that a nested capture of an init-capture is not itself an
221  // init-capture.
222  return !isNested() && isVariableCapture() && getVariable()->isInitCapture();
223 }
224 
226  for (auto &Cap : Captures)
227  if (Cap.isVLATypeCapture() && Cap.getCapturedVLAType() == VAT)
228  return true;
229  return false;
230 }
231 
233  llvm::function_ref<void(VarDecl *, Expr *)> Callback) const {
234  for (Expr *E : PotentiallyCapturingExprs) {
235  if (auto *DRE = dyn_cast<DeclRefExpr>(E)) {
236  Callback(cast<VarDecl>(DRE->getFoundDecl()), E);
237  } else if (auto *ME = dyn_cast<MemberExpr>(E)) {
238  Callback(cast<VarDecl>(ME->getMemberDecl()), E);
239  } else if (auto *FP = dyn_cast<FunctionParmPackExpr>(E)) {
240  for (VarDecl *VD : *FP)
241  Callback(VD, E);
242  } else {
243  llvm_unreachable("unexpected expression in potential captures list");
244  }
245  }
246 }
247 
ObjCPropertyRefExpr - A dot-syntax expression to access an ObjC property.
Definition: ExprObjC.h:614
Expr * getSyntacticForm()
Return the syntactic form of this expression, i.e.
Definition: Expr.h:5717
ValueDecl * getMemberDecl() const
Retrieve the member declaration to which this expression refers.
Definition: Expr.h:2894
bool HasFallthroughStmt
Whether there is a fallthrough statement in this function.
Definition: ScopeInfo.h:127
bool isSuperReceiver() const
Definition: ExprObjC.h:776
bool isVLATypeCaptured(const VariableArrayType *VAT) const
Determine whether the given variable-array type has been captured.
Definition: ScopeInfo.cpp:225
Expr * getBase() const
Definition: Expr.h:2888
static const NamedDecl * getBestPropertyDecl(const ObjCPropertyRefExpr *PropE)
Definition: ScopeInfo.cpp:60
std::pair< Stmt *, Stmt * > CoroutineSuspends
The initial and final coroutine suspend points.
Definition: ScopeInfo.h:200
Represents a variable declaration or definition.
Definition: Decl.h:827
ObjCInterfaceDecl * getClassReceiver() const
Definition: ExprObjC.h:771
ObjCMethodDecl - Represents an instance or class method declaration.
Definition: DeclObjC.h:138
static ObjCPropertyDecl * findPropertyDecl(const DeclContext *DC, const IdentifierInfo *propertyID, ObjCPropertyQueryKind queryKind)
Lookup a property by name in the specified DeclContext.
Definition: DeclObjC.cpp:176
bool NeedsCoroutineSuspends
True only when this function has not already built, or attempted to build, the initial and final coro...
Definition: ScopeInfo.h:157
Defines the clang::Expr interface and subclasses for C++ expressions.
bool HasDroppedStmt
Whether a statement was dropped because it was invalid.
Definition: ScopeInfo.h:121
ObjCPropertyDecl * getExplicitProperty() const
Definition: ExprObjC.h:707
llvm::SmallMapVector< ParmVarDecl *, Stmt *, 4 > CoroutineParameterMoves
A mapping between the coroutine function parameters that were moved to the coroutine frame...
Definition: ScopeInfo.h:197
void visitPotentialCaptures(llvm::function_ref< void(VarDecl *, Expr *)> Callback) const
Definition: ScopeInfo.cpp:232
bool isExplicitProperty() const
Definition: ExprObjC.h:705
llvm::SmallPtrSet< const BlockDecl *, 1 > Blocks
The set of blocks that are introduced in this function.
Definition: ScopeInfo.h:207
Expr * getSourceExpr() const
The source expression of an opaque value expression is the expression which originally generated the ...
Definition: Expr.h:1108
SourceLocation FirstSEHTryLoc
First SEH &#39;__try&#39; statement in the current function.
Definition: ScopeInfo.h:174
DiagnosticErrorTrap ErrorTrap
Used to determine if errors occurred in this function or block.
Definition: ScopeInfo.h:177
bool isClassReceiver() const
Definition: ExprObjC.h:777
Expr * IgnoreParenCasts() LLVM_READONLY
Skip past any parentheses and casts which might surround this expression until reaching a fixed point...
Definition: Expr.cpp:2971
bool isObjCSelfExpr() const
Check if this expression is the ObjC &#39;self&#39; implicit parameter.
Definition: Expr.cpp:3823
SourceLocation FirstCXXTryLoc
First C++ &#39;try&#39; statement in the current function.
Definition: ScopeInfo.h:171
ObjCIvarDecl * getDecl()
Definition: ExprObjC.h:576
ConditionalOperator - The ?: ternary operator.
Definition: Expr.h:3707
SmallVector< ReturnStmt *, 4 > Returns
The list of return statements that occur within the function or block, if there is any chance of appl...
Definition: ScopeInfo.h:190
void recordUseOfWeak(const ExprT *E, bool IsRead=true)
Record that a weak object was accessed.
Definition: ScopeInfo.h:1021
This represents one expression.
Definition: Expr.h:108
SmallVector< SwitchInfo, 8 > SwitchStack
SwitchStack - This is the current set of active switch statements in the block.
Definition: ScopeInfo.h:185
bool HasBranchProtectedScope
Whether this function contains a VLA, @try, try, C++ initializer, or anything else that can&#39;t be jump...
Definition: ScopeInfo.h:112
An expression that sends a message to the given Objective-C object or class.
Definition: ExprObjC.h:950
ObjCMethodDecl * getImplicitPropertyGetter() const
Definition: ExprObjC.h:712
VarDecl * CoroutinePromise
The promise object for this coroutine, if any.
Definition: ScopeInfo.h:193
OpaqueValueExpr - An expression referring to an opaque object of a fixed type and value class...
Definition: Expr.h:1050
unsigned getNumArgs() const
Return the number of actual arguments in this message, not counting the receiver. ...
Definition: ExprObjC.h:1382
PseudoObjectExpr - An expression which accesses a pseudo-object l-value.
Definition: Expr.h:5673
bool HasPotentialAvailabilityViolations
Whether we make reference to a declaration that could be unavailable.
Definition: ScopeInfo.h:131
Encodes a location in the source.
bool ObjCWarnForNoDesignatedInitChain
This starts true for a method marked as designated initializer and will be set to false if there is a...
Definition: ScopeInfo.h:144
void reset()
Set to initial state of "no errors occurred".
Definition: Diagnostic.h:1021
SourceLocation FirstCoroutineStmtLoc
First coroutine statement in the current function.
Definition: ScopeInfo.h:165
Represents one property declaration in an Objective-C interface.
Definition: DeclObjC.h:728
bool ObjCIsDesignatedInit
True when this is a method marked as a designated initializer.
Definition: ScopeInfo.h:139
bool ObjCShouldCallSuper
A flag that is set when parsing a method that must call super&#39;s implementation, such as -dealloc...
Definition: ScopeInfo.h:136
bool HasOMPDeclareReductionCombiner
True if current scope is for OpenMP declare reduction combiner.
Definition: ScopeInfo.h:124
Expr * getInstanceReceiver()
Returns the object expression (receiver) for an instance message, or null for a message that is not a...
Definition: ExprObjC.h:1260
Dataflow Directional Tag Classes.
bool ObjCIsSecondaryInit
True when this is an initializer method not marked as a designated initializer within a class that ha...
Definition: ScopeInfo.h:149
bool HasIndirectGoto
Whether this function contains any indirect gotos.
Definition: ScopeInfo.h:118
StmtClass getStmtClass() const
Definition: Stmt.h:1097
Represents a simple identification of a weak object.
Definition: ScopeInfo.h:244
bool ObjCWarnForNoInitDelegation
This starts true for a secondary initializer method and will be set to false if there is an invocatio...
Definition: ScopeInfo.h:153
Expr * IgnoreParenImpCasts() LLVM_READONLY
Skip past any parentheses and implicit casts which might surround this expression until reaching a fi...
Definition: Expr.cpp:2966
SourceLocation FirstReturnLoc
First &#39;return&#39; statement in the current function.
Definition: ScopeInfo.h:168
void markSafeWeakUse(const Expr *E)
Record that a given expression is a "safe" access of a weak object (e.g.
Definition: ScopeInfo.cpp:157
const Expr * getBase() const
Definition: ExprObjC.h:580
ObjCIvarRefExpr - A reference to an ObjC instance variable.
Definition: ExprObjC.h:546
bool isInitCapture() const
Determine whether this capture is an init-capture.
Definition: ScopeInfo.cpp:219
Defines the C++ Decl subclasses, other than those for templates (found in DeclTemplate.h) and friends (in DeclFriend.h).
MemberExpr - [C99 6.5.2.3] Structure and Union Members.
Definition: Expr.h:2811
SmallVector< PossiblyUnreachableDiag, 4 > PossiblyUnreachableDiags
A list of PartialDiagnostics created but delayed within the current function scope.
Definition: ScopeInfo.h:215
BinaryConditionalOperator - The GNU extension to the conditional operator which allows the middle ope...
Definition: Expr.h:3780
llvm::SmallPtrSet< const ParmVarDecl *, 8 > ModifiedNonNullParams
A list of parameters which have the nonnull attribute and are modified in the function.
Definition: ScopeInfo.h:219
Represents a single use of a weak object.
Definition: ScopeInfo.h:328
bool isObjectReceiver() const
Definition: ExprObjC.h:775
A reference to a declared variable, function, enum, etc.
Definition: Expr.h:1146
#define true
Definition: stdbool.h:16
const Expr * getBase() const
Definition: ExprObjC.h:756
llvm::TinyPtrVector< VarDecl * > ByrefBlockVars
The set of __block variables that are introduced in this function.
Definition: ScopeInfo.h:210
This represents a decl that may have a name.
Definition: Decl.h:248
Represents a C array with a specified size that is not an integer-constant-expression.
Definition: Type.h:3010
void Clear()
Clear out the information in this function scope, making it suitable for reuse.
Definition: ScopeInfo.cpp:25
bool HasBranchIntoScope
Whether this function contains any switches or direct gotos.
Definition: ScopeInfo.h:115