clang  6.0.0svn
ScopeInfo.cpp
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1 //===--- ScopeInfo.cpp - Information about a semantic context -------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements FunctionScopeInfo and its subclasses, which contain
11 // information about a single function, block, lambda, or method body.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "clang/Sema/ScopeInfo.h"
16 #include "clang/AST/Decl.h"
17 #include "clang/AST/DeclCXX.h"
18 #include "clang/AST/DeclObjC.h"
19 #include "clang/AST/Expr.h"
20 #include "clang/AST/ExprCXX.h"
21 #include "clang/AST/ExprObjC.h"
22 
23 using namespace clang;
24 using namespace sema;
25 
28  HasBranchIntoScope = false;
29  HasIndirectGoto = false;
30  HasDroppedStmt = false;
32  HasFallthroughStmt = false;
34  ObjCShouldCallSuper = false;
35  ObjCIsDesignatedInit = false;
37  ObjCIsSecondaryInit = false;
42 
43  // Coroutine state
45  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 }
57 
58 static const NamedDecl *getBestPropertyDecl(const ObjCPropertyRefExpr *PropE) {
59  if (PropE->isExplicitProperty())
60  return PropE->getExplicitProperty();
61 
62  return PropE->getImplicitPropertyGetter();
63 }
64 
65 FunctionScopeInfo::WeakObjectProfileTy::BaseInfoTy
66 FunctionScopeInfo::WeakObjectProfileTy::getBaseInfo(const Expr *E) {
67  E = E->IgnoreParenCasts();
68 
69  const NamedDecl *D = nullptr;
70  bool IsExact = false;
71 
72  switch (E->getStmtClass()) {
73  case Stmt::DeclRefExprClass:
74  D = cast<DeclRefExpr>(E)->getDecl();
75  IsExact = isa<VarDecl>(D);
76  break;
77  case Stmt::MemberExprClass: {
78  const MemberExpr *ME = cast<MemberExpr>(E);
79  D = ME->getMemberDecl();
80  IsExact = isa<CXXThisExpr>(ME->getBase()->IgnoreParenImpCasts());
81  break;
82  }
83  case Stmt::ObjCIvarRefExprClass: {
84  const ObjCIvarRefExpr *IE = cast<ObjCIvarRefExpr>(E);
85  D = IE->getDecl();
86  IsExact = IE->getBase()->isObjCSelfExpr();
87  break;
88  }
89  case Stmt::PseudoObjectExprClass: {
90  const PseudoObjectExpr *POE = cast<PseudoObjectExpr>(E);
91  const ObjCPropertyRefExpr *BaseProp =
92  dyn_cast<ObjCPropertyRefExpr>(POE->getSyntacticForm());
93  if (BaseProp) {
94  D = getBestPropertyDecl(BaseProp);
95 
96  if (BaseProp->isObjectReceiver()) {
97  const Expr *DoubleBase = BaseProp->getBase();
98  if (const OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(DoubleBase))
99  DoubleBase = OVE->getSourceExpr();
100 
101  IsExact = DoubleBase->isObjCSelfExpr();
102  }
103  }
104  break;
105  }
106  default:
107  break;
108  }
109 
110  return BaseInfoTy(D, IsExact);
111 }
112 
114  RecordDecl *RD = nullptr;
115  if (auto *LSI = dyn_cast<LambdaScopeInfo>(this))
116  RD = LSI->Lambda;
117  else if (auto CRSI = dyn_cast<CapturedRegionScopeInfo>(this))
118  RD = CRSI->TheRecordDecl;
119 
120  if (RD)
121  for (auto *FD : RD->fields()) {
122  if (FD->hasCapturedVLAType() && FD->getCapturedVLAType() == VAT)
123  return true;
124  }
125  return false;
126 }
127 
128 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(
129  const ObjCPropertyRefExpr *PropE)
130  : Base(nullptr, true), Property(getBestPropertyDecl(PropE)) {
131 
132  if (PropE->isObjectReceiver()) {
133  const OpaqueValueExpr *OVE = cast<OpaqueValueExpr>(PropE->getBase());
134  const Expr *E = OVE->getSourceExpr();
135  Base = getBaseInfo(E);
136  } else if (PropE->isClassReceiver()) {
137  Base.setPointer(PropE->getClassReceiver());
138  } else {
139  assert(PropE->isSuperReceiver());
140  }
141 }
142 
143 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(const Expr *BaseE,
144  const ObjCPropertyDecl *Prop)
145  : Base(nullptr, true), Property(Prop) {
146  if (BaseE)
147  Base = getBaseInfo(BaseE);
148  // else, this is a message accessing a property on super.
149 }
150 
151 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(
152  const DeclRefExpr *DRE)
153  : Base(nullptr, true), Property(DRE->getDecl()) {
154  assert(isa<VarDecl>(Property));
155 }
156 
157 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(
158  const ObjCIvarRefExpr *IvarE)
159  : Base(getBaseInfo(IvarE->getBase())), Property(IvarE->getDecl()) {
160 }
161 
163  const ObjCPropertyDecl *Prop) {
164  assert(Msg && Prop);
165  WeakUseVector &Uses =
166  WeakObjectUses[WeakObjectProfileTy(Msg->getInstanceReceiver(), Prop)];
167  Uses.push_back(WeakUseTy(Msg, Msg->getNumArgs() == 0));
168 }
169 
171  E = E->IgnoreParenCasts();
172 
173  if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(E)) {
174  markSafeWeakUse(POE->getSyntacticForm());
175  return;
176  }
177 
178  if (const ConditionalOperator *Cond = dyn_cast<ConditionalOperator>(E)) {
179  markSafeWeakUse(Cond->getTrueExpr());
180  markSafeWeakUse(Cond->getFalseExpr());
181  return;
182  }
183 
184  if (const BinaryConditionalOperator *Cond =
185  dyn_cast<BinaryConditionalOperator>(E)) {
186  markSafeWeakUse(Cond->getCommon());
187  markSafeWeakUse(Cond->getFalseExpr());
188  return;
189  }
190 
191  // Has this weak object been seen before?
192  FunctionScopeInfo::WeakObjectUseMap::iterator Uses = WeakObjectUses.end();
193  if (const ObjCPropertyRefExpr *RefExpr = dyn_cast<ObjCPropertyRefExpr>(E)) {
194  if (!RefExpr->isObjectReceiver())
195  return;
196  if (isa<OpaqueValueExpr>(RefExpr->getBase()))
197  Uses = WeakObjectUses.find(WeakObjectProfileTy(RefExpr));
198  else {
199  markSafeWeakUse(RefExpr->getBase());
200  return;
201  }
202  }
203  else if (const ObjCIvarRefExpr *IvarE = dyn_cast<ObjCIvarRefExpr>(E))
204  Uses = WeakObjectUses.find(WeakObjectProfileTy(IvarE));
205  else if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
206  if (isa<VarDecl>(DRE->getDecl()))
207  Uses = WeakObjectUses.find(WeakObjectProfileTy(DRE));
208  } else if (const ObjCMessageExpr *MsgE = dyn_cast<ObjCMessageExpr>(E)) {
209  if (const ObjCMethodDecl *MD = MsgE->getMethodDecl()) {
210  if (const ObjCPropertyDecl *Prop = MD->findPropertyDecl()) {
211  Uses =
212  WeakObjectUses.find(WeakObjectProfileTy(MsgE->getInstanceReceiver(),
213  Prop));
214  }
215  }
216  }
217  else
218  return;
219 
220  if (Uses == WeakObjectUses.end())
221  return;
222 
223  // Has there been a read from the object using this Expr?
224  FunctionScopeInfo::WeakUseVector::reverse_iterator ThisUse =
225  llvm::find(llvm::reverse(Uses->second), WeakUseTy(E, true));
226  if (ThisUse == Uses->second.rend())
227  return;
228 
229  ThisUse->markSafe();
230 }
231 
233  Expr *&E) const {
234  assert(Idx < getNumPotentialVariableCaptures() &&
235  "Index of potential capture must be within 0 to less than the "
236  "number of captures!");
237  E = PotentiallyCapturingExprs[Idx];
238  if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
239  VD = dyn_cast<VarDecl>(DRE->getFoundDecl());
240  else if (MemberExpr *ME = dyn_cast<MemberExpr>(E))
241  VD = dyn_cast<VarDecl>(ME->getMemberDecl());
242  else
243  llvm_unreachable("Only DeclRefExprs or MemberExprs should be added for "
244  "potential captures");
245  assert(VD);
246 }
247 
ObjCPropertyRefExpr - A dot-syntax expression to access an ObjC property.
Definition: ExprObjC.h:577
Expr * getSyntacticForm()
Return the syntactic form of this expression, i.e.
Definition: Expr.h:5013
ValueDecl * getMemberDecl() const
Retrieve the member declaration to which this expression refers.
Definition: Expr.h:2483
void getPotentialVariableCapture(unsigned Idx, VarDecl *&VD, Expr *&E) const
Definition: ScopeInfo.cpp:232
bool HasFallthroughStmt
Whether there is a fallthrough statement in this function.
Definition: ScopeInfo.h:113
bool isSuperReceiver() const
Definition: ExprObjC.h:739
bool isVLATypeCaptured(const VariableArrayType *VAT) const
Determine whether the given variable-array type has been captured.
Definition: ScopeInfo.cpp:113
Expr * getBase() const
Definition: Expr.h:2477
static const NamedDecl * getBestPropertyDecl(const ObjCPropertyRefExpr *PropE)
Definition: ScopeInfo.cpp:58
std::pair< Stmt *, Stmt * > CoroutineSuspends
The initial and final coroutine suspend points.
Definition: ScopeInfo.h:176
VarDecl - An instance of this class is created to represent a variable declaration or definition...
Definition: Decl.h:807
SmallVector< SwitchStmt *, 8 > SwitchStack
SwitchStack - This is the current set of active switch statements in the block.
Definition: ScopeInfo.h:165
ObjCInterfaceDecl * getClassReceiver() const
Definition: ExprObjC.h:734
ObjCMethodDecl - Represents an instance or class method declaration.
Definition: DeclObjC.h:139
static ObjCPropertyDecl * findPropertyDecl(const DeclContext *DC, const IdentifierInfo *propertyID, ObjCPropertyQueryKind queryKind)
Lookup a property by name in the specified DeclContext.
Definition: DeclObjC.cpp:170
bool NeedsCoroutineSuspends
True only when this function has not already built, or attempted to build, the initial and final coro...
Definition: ScopeInfo.h:141
Defines the clang::Expr interface and subclasses for C++ expressions.
bool HasDroppedStmt
Whether a statement was dropped because it was invalid.
Definition: ScopeInfo.h:107
ObjCPropertyDecl * getExplicitProperty() const
Definition: ExprObjC.h:670
RecordDecl - Represents a struct/union/class.
Definition: Decl.h:3482
bool isExplicitProperty() const
Definition: ExprObjC.h:668
field_range fields() const
Definition: Decl.h:3613
Expr * getSourceExpr() const
The source expression of an opaque value expression is the expression which originally generated the ...
Definition: Expr.h:926
SourceLocation FirstSEHTryLoc
First SEH &#39;__try&#39; statement in the current function.
Definition: ScopeInfo.h:158
DiagnosticErrorTrap ErrorTrap
Used to determine if errors occurred in this function or block.
Definition: ScopeInfo.h:161
bool isClassReceiver() const
Definition: ExprObjC.h:740
Expr * IgnoreParenCasts() LLVM_READONLY
IgnoreParenCasts - Ignore parentheses and casts.
Definition: Expr.cpp:2463
bool isObjCSelfExpr() const
Check if this expression is the ObjC &#39;self&#39; implicit parameter.
Definition: Expr.cpp:3412
SourceLocation FirstCXXTryLoc
First C++ &#39;try&#39; statement in the current function.
Definition: ScopeInfo.h:155
ObjCIvarDecl * getDecl()
Definition: ExprObjC.h:543
ConditionalOperator - The ?: ternary operator.
Definition: Expr.h:3269
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:170
void recordUseOfWeak(const ExprT *E, bool IsRead=true)
Record that a weak object was accessed.
Definition: ScopeInfo.h:958
Expr - This represents one expression.
Definition: Expr.h:106
bool HasBranchProtectedScope
Whether this function contains a VLA, @try, try, C++ initializer, or anything else that can&#39;t be jump...
Definition: ScopeInfo.h:98
An expression that sends a message to the given Objective-C object or class.
Definition: ExprObjC.h:903
ObjCMethodDecl * getImplicitPropertyGetter() const
Definition: ExprObjC.h:675
llvm::SmallPtrSet< const ParmVarDecl *, 8 > ModifiedNonNullParams
A list of parameters which have the nonnull attribute and are modified in the function.
Definition: ScopeInfo.h:189
VarDecl * CoroutinePromise
The promise object for this coroutine, if any.
Definition: ScopeInfo.h:173
OpaqueValueExpr - An expression referring to an opaque object of a fixed type and value class...
Definition: Expr.h:868
unsigned getNumArgs() const
Return the number of actual arguments in this message, not counting the receiver. ...
Definition: ExprObjC.h:1328
PseudoObjectExpr - An expression which accesses a pseudo-object l-value.
Definition: Expr.h:4969
bool HasPotentialAvailabilityViolations
Whether we make reference to a declaration that could be unavailable.
Definition: ScopeInfo.h:117
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:129
void reset()
Set to initial state of "no errors occurred".
Definition: Diagnostic.h:933
SourceLocation FirstCoroutineStmtLoc
First coroutine statement in the current function.
Definition: ScopeInfo.h:149
Represents one property declaration in an Objective-C interface.
Definition: DeclObjC.h:746
bool ObjCIsDesignatedInit
True when this is a method marked as a designated initializer.
Definition: ScopeInfo.h:125
bool ObjCShouldCallSuper
A flag that is set when parsing a method that must call super&#39;s implementation, such as -dealloc...
Definition: ScopeInfo.h:122
bool HasOMPDeclareReductionCombiner
True if current scope is for OpenMP declare reduction combiner.
Definition: ScopeInfo.h:110
Expr * getInstanceReceiver()
Returns the object expression (receiver) for an instance message, or null for a message that is not a...
Definition: ExprObjC.h:1206
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:134
bool HasIndirectGoto
Whether this function contains any indirect gotos.
Definition: ScopeInfo.h:104
StmtClass getStmtClass() const
Definition: Stmt.h:378
Represents a simple identification of a weak object.
Definition: ScopeInfo.h:214
bool ObjCWarnForNoInitDelegation
This starts true for a secondary initializer method and will be set to false if there is an invocatio...
Definition: ScopeInfo.h:137
Expr * IgnoreParenImpCasts() LLVM_READONLY
IgnoreParenImpCasts - Ignore parentheses and implicit casts.
Definition: Expr.cpp:2550
SourceLocation FirstReturnLoc
First &#39;return&#39; statement in the current function.
Definition: ScopeInfo.h:152
void markSafeWeakUse(const Expr *E)
Record that a given expression is a "safe" access of a weak object (e.g.
Definition: ScopeInfo.cpp:170
const Expr * getBase() const
Definition: ExprObjC.h:547
ObjCIvarRefExpr - A reference to an ObjC instance variable.
Definition: ExprObjC.h:513
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:2387
SmallVector< PossiblyUnreachableDiag, 4 > PossiblyUnreachableDiags
A list of PartialDiagnostics created but delayed within the current function scope.
Definition: ScopeInfo.h:185
BinaryConditionalOperator - The GNU extension to the conditional operator which allows the middle ope...
Definition: Expr.h:3342
Represents a single use of a weak object.
Definition: ScopeInfo.h:296
bool isObjectReceiver() const
Definition: ExprObjC.h:738
A reference to a declared variable, function, enum, etc.
Definition: Expr.h:956
#define true
Definition: stdbool.h:32
const Expr * getBase() const
Definition: ExprObjC.h:719
NamedDecl - This represents a decl with a name.
Definition: Decl.h:245
Represents a C array with a specified size that is not an integer-constant-expression.
Definition: Type.h:2719
void Clear()
Clear out the information in this function scope, making it suitable for reuse.
Definition: ScopeInfo.cpp:26
bool HasBranchIntoScope
Whether this function contains any switches or direct gotos.
Definition: ScopeInfo.h:101