Clang Project

clang_source_code/lib/Sema/ScopeInfo.cpp
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
22using namespace clang;
23using namespace sema;
24
25void FunctionScopeInfo::Clear() {
26  HasBranchProtectedScope = false;
27  HasBranchIntoScope = false;
28  HasIndirectGoto = false;
29  HasDroppedStmt = false;
30  HasOMPDeclareReductionCombiner = false;
31  HasFallthroughStmt = false;
32  HasPotentialAvailabilityViolations = false;
33  ObjCShouldCallSuper = false;
34  ObjCIsDesignatedInit = false;
35  ObjCWarnForNoDesignatedInitChain = false;
36  ObjCIsSecondaryInit = false;
37  ObjCWarnForNoInitDelegation = false;
38  FirstReturnLoc = SourceLocation();
39  FirstCXXTryLoc = SourceLocation();
40  FirstSEHTryLoc = SourceLocation();
41
42  // Coroutine state
43  FirstCoroutineStmtLoc = SourceLocation();
44  CoroutinePromise = nullptr;
45  CoroutineParameterMoves.clear();
46  NeedsCoroutineSuspends = true;
47  CoroutineSuspends.first = nullptr;
48  CoroutineSuspends.second = nullptr;
49
50  SwitchStack.clear();
51  Returns.clear();
52  ErrorTrap.reset();
53  PossiblyUnreachableDiags.clear();
54  WeakObjectUses.clear();
55  ModifiedNonNullParams.clear();
56  Blocks.clear();
57  ByrefBlockVars.clear();
58}
59
60static const NamedDecl *getBestPropertyDecl(const ObjCPropertyRefExpr *PropE) {
61  if (PropE->isExplicitProperty())
62    return PropE->getExplicitProperty();
63
64  return PropE->getImplicitPropertyGetter();
65}
66
67FunctionScopeInfo::WeakObjectProfileTy::BaseInfoTy
68FunctionScopeInfo::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
115bool CapturingScopeInfo::isVLATypeCaptured(const VariableArrayType *VAT) const {
116  RecordDecl *RD = nullptr;
117  if (auto *LSI = dyn_cast<LambdaScopeInfo>(this))
118    RD = LSI->Lambda;
119  else if (auto CRSI = dyn_cast<CapturedRegionScopeInfo>(this))
120    RD = CRSI->TheRecordDecl;
121
122  if (RD)
123    for (auto *FD : RD->fields()) {
124      if (FD->hasCapturedVLAType() && FD->getCapturedVLAType() == VAT)
125        return true;
126    }
127  return false;
128}
129
130FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(
131                                          const ObjCPropertyRefExpr *PropE)
132    : Base(nullptr, true), Property(getBestPropertyDecl(PropE)) {
133
134  if (PropE->isObjectReceiver()) {
135    const OpaqueValueExpr *OVE = cast<OpaqueValueExpr>(PropE->getBase());
136    const Expr *E = OVE->getSourceExpr();
137    Base = getBaseInfo(E);
138  } else if (PropE->isClassReceiver()) {
139    Base.setPointer(PropE->getClassReceiver());
140  } else {
141    isSuperReceiver()", "/home/seafit/code_projects/clang_source/clang/lib/Sema/ScopeInfo.cpp", 141, __PRETTY_FUNCTION__))" file_link="../../../include/assert.h.html#88" macro="true">assert(PropE->isSuperReceiver());
142  }
143}
144
145FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(const Expr *BaseE,
146                                                const ObjCPropertyDecl *Prop)
147    : Base(nullptr, true), Property(Prop) {
148  if (BaseE)
149    Base = getBaseInfo(BaseE);
150  // else, this is a message accessing a property on super.
151}
152
153FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(
154                                                      const DeclRefExpr *DRE)
155  : Base(nullptr, true), Property(DRE->getDecl()) {
156  (Property)", "/home/seafit/code_projects/clang_source/clang/lib/Sema/ScopeInfo.cpp", 156, __PRETTY_FUNCTION__))" file_link="../../../include/assert.h.html#88" macro="true">assert(isa<VarDecl>(Property));
157}
158
159FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy(
160                                                  const ObjCIvarRefExpr *IvarE)
161  : Base(getBaseInfo(IvarE->getBase())), Property(IvarE->getDecl()) {
162}
163
164void FunctionScopeInfo::recordUseOfWeak(const ObjCMessageExpr *Msg,
165                                        const ObjCPropertyDecl *Prop) {
166  assert(Msg && Prop);
167  WeakUseVector &Uses =
168    WeakObjectUses[WeakObjectProfileTy(Msg->getInstanceReceiver(), Prop)];
169  Uses.push_back(WeakUseTy(Msg, Msg->getNumArgs() == 0));
170}
171
172void FunctionScopeInfo::markSafeWeakUse(const Expr *E) {
173  E = E->IgnoreParenCasts();
174
175  if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(E)) {
176    markSafeWeakUse(POE->getSyntacticForm());
177    return;
178  }
179
180  if (const ConditionalOperator *Cond = dyn_cast<ConditionalOperator>(E)) {
181    markSafeWeakUse(Cond->getTrueExpr());
182    markSafeWeakUse(Cond->getFalseExpr());
183    return;
184  }
185
186  if (const BinaryConditionalOperator *Cond =
187        dyn_cast<BinaryConditionalOperator>(E)) {
188    markSafeWeakUse(Cond->getCommon());
189    markSafeWeakUse(Cond->getFalseExpr());
190    return;
191  }
192
193  // Has this weak object been seen before?
194  FunctionScopeInfo::WeakObjectUseMap::iterator Uses = WeakObjectUses.end();
195  if (const ObjCPropertyRefExpr *RefExpr = dyn_cast<ObjCPropertyRefExpr>(E)) {
196    if (!RefExpr->isObjectReceiver())
197      return;
198    if (isa<OpaqueValueExpr>(RefExpr->getBase()))
199     Uses = WeakObjectUses.find(WeakObjectProfileTy(RefExpr));
200    else {
201      markSafeWeakUse(RefExpr->getBase());
202      return;
203    }
204  }
205  else if (const ObjCIvarRefExpr *IvarE = dyn_cast<ObjCIvarRefExpr>(E))
206    Uses = WeakObjectUses.find(WeakObjectProfileTy(IvarE));
207  else if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
208    if (isa<VarDecl>(DRE->getDecl()))
209      Uses = WeakObjectUses.find(WeakObjectProfileTy(DRE));
210  } else if (const ObjCMessageExpr *MsgE = dyn_cast<ObjCMessageExpr>(E)) {
211    if (const ObjCMethodDecl *MD = MsgE->getMethodDecl()) {
212      if (const ObjCPropertyDecl *Prop = MD->findPropertyDecl()) {
213        Uses =
214          WeakObjectUses.find(WeakObjectProfileTy(MsgE->getInstanceReceiver(),
215                                                  Prop));
216      }
217    }
218  }
219  else
220    return;
221
222  if (Uses == WeakObjectUses.end())
223    return;
224
225  // Has there been a read from the object using this Expr?
226  FunctionScopeInfo::WeakUseVector::reverse_iterator ThisUse =
227      llvm::find(llvm::reverse(Uses->second), WeakUseTy(E, true));
228  if (ThisUse == Uses->second.rend())
229    return;
230
231  ThisUse->markSafe();
232}
233
234void LambdaScopeInfo::getPotentialVariableCapture(unsigned Idx, VarDecl *&VD,
235                                                  Expr *&E) const {
236   (0) . __assert_fail ("Idx < getNumPotentialVariableCaptures() && \"Index of potential capture must be within 0 to less than the \" \"number of captures!\"", "/home/seafit/code_projects/clang_source/clang/lib/Sema/ScopeInfo.cpp", 238, __PRETTY_FUNCTION__))" file_link="../../../include/assert.h.html#88" macro="true">assert(Idx < getNumPotentialVariableCaptures() &&
237 (0) . __assert_fail ("Idx < getNumPotentialVariableCaptures() && \"Index of potential capture must be within 0 to less than the \" \"number of captures!\"", "/home/seafit/code_projects/clang_source/clang/lib/Sema/ScopeInfo.cpp", 238, __PRETTY_FUNCTION__))" file_link="../../../include/assert.h.html#88" macro="true">         "Index of potential capture must be within 0 to less than the "
238 (0) . __assert_fail ("Idx < getNumPotentialVariableCaptures() && \"Index of potential capture must be within 0 to less than the \" \"number of captures!\"", "/home/seafit/code_projects/clang_source/clang/lib/Sema/ScopeInfo.cpp", 238, __PRETTY_FUNCTION__))" file_link="../../../include/assert.h.html#88" macro="true">         "number of captures!");
239  E = PotentiallyCapturingExprs[Idx];
240  if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
241    VD = dyn_cast<VarDecl>(DRE->getFoundDecl());
242  else if (MemberExpr *ME = dyn_cast<MemberExpr>(E))
243    VD = dyn_cast<VarDecl>(ME->getMemberDecl());
244  else
245    llvm_unreachable("Only DeclRefExprs or MemberExprs should be added for "
246    "potential captures");
247  assert(VD);
248}
249
250FunctionScopeInfo::~FunctionScopeInfo() { }
251BlockScopeInfo::~BlockScopeInfo() { }
252CapturedRegionScopeInfo::~CapturedRegionScopeInfo() { }
253
clang::sema::FunctionScopeInfo::Clear
clang::sema::FunctionScopeInfo::WeakObjectProfileTy::getBaseInfo
clang::sema::CapturingScopeInfo::isVLATypeCaptured
clang::sema::FunctionScopeInfo::recordUseOfWeak
clang::sema::FunctionScopeInfo::markSafeWeakUse
clang::sema::LambdaScopeInfo::getPotentialVariableCapture
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