1 //===--- TransProtectedScope.cpp - Transformations to ARC mode ------------===//
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 // Adds brackets in case statements that "contain" initialization of retaining
10 // variable, thus emitting the "switch case is in protected scope" error.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "Internals.h"
15 #include "Transforms.h"
16 #include "clang/AST/ASTContext.h"
17 #include "clang/Basic/SourceManager.h"
18 #include "clang/Sema/SemaDiagnostic.h"
19
20 using namespace clang;
21 using namespace arcmt;
22 using namespace trans;
23
24 namespace {
25
26 class LocalRefsCollector : public RecursiveASTVisitor<LocalRefsCollector> {
27 SmallVectorImpl<DeclRefExpr *> &Refs;
28
29 public:
LocalRefsCollector(SmallVectorImpl<DeclRefExpr * > & refs)30 LocalRefsCollector(SmallVectorImpl<DeclRefExpr *> &refs)
31 : Refs(refs) { }
32
VisitDeclRefExpr(DeclRefExpr * E)33 bool VisitDeclRefExpr(DeclRefExpr *E) {
34 if (ValueDecl *D = E->getDecl())
35 if (D->getDeclContext()->getRedeclContext()->isFunctionOrMethod())
36 Refs.push_back(E);
37 return true;
38 }
39 };
40
41 struct CaseInfo {
42 SwitchCase *SC;
43 SourceRange Range;
44 enum {
45 St_Unchecked,
46 St_CannotFix,
47 St_Fixed
48 } State;
49
CaseInfo__anon2f6a04b40111::CaseInfo50 CaseInfo() : SC(nullptr), State(St_Unchecked) {}
CaseInfo__anon2f6a04b40111::CaseInfo51 CaseInfo(SwitchCase *S, SourceRange Range)
52 : SC(S), Range(Range), State(St_Unchecked) {}
53 };
54
55 class CaseCollector : public RecursiveASTVisitor<CaseCollector> {
56 ParentMap &PMap;
57 SmallVectorImpl<CaseInfo> &Cases;
58
59 public:
CaseCollector(ParentMap & PMap,SmallVectorImpl<CaseInfo> & Cases)60 CaseCollector(ParentMap &PMap, SmallVectorImpl<CaseInfo> &Cases)
61 : PMap(PMap), Cases(Cases) { }
62
VisitSwitchStmt(SwitchStmt * S)63 bool VisitSwitchStmt(SwitchStmt *S) {
64 SwitchCase *Curr = S->getSwitchCaseList();
65 if (!Curr)
66 return true;
67 Stmt *Parent = getCaseParent(Curr);
68 Curr = Curr->getNextSwitchCase();
69 // Make sure all case statements are in the same scope.
70 while (Curr) {
71 if (getCaseParent(Curr) != Parent)
72 return true;
73 Curr = Curr->getNextSwitchCase();
74 }
75
76 SourceLocation NextLoc = S->getEndLoc();
77 Curr = S->getSwitchCaseList();
78 // We iterate over case statements in reverse source-order.
79 while (Curr) {
80 Cases.push_back(
81 CaseInfo(Curr, SourceRange(Curr->getBeginLoc(), NextLoc)));
82 NextLoc = Curr->getBeginLoc();
83 Curr = Curr->getNextSwitchCase();
84 }
85 return true;
86 }
87
getCaseParent(SwitchCase * S)88 Stmt *getCaseParent(SwitchCase *S) {
89 Stmt *Parent = PMap.getParent(S);
90 while (Parent && (isa<SwitchCase>(Parent) || isa<LabelStmt>(Parent)))
91 Parent = PMap.getParent(Parent);
92 return Parent;
93 }
94 };
95
96 class ProtectedScopeFixer {
97 MigrationPass &Pass;
98 SourceManager &SM;
99 SmallVector<CaseInfo, 16> Cases;
100 SmallVector<DeclRefExpr *, 16> LocalRefs;
101
102 public:
ProtectedScopeFixer(BodyContext & BodyCtx)103 ProtectedScopeFixer(BodyContext &BodyCtx)
104 : Pass(BodyCtx.getMigrationContext().Pass),
105 SM(Pass.Ctx.getSourceManager()) {
106
107 CaseCollector(BodyCtx.getParentMap(), Cases)
108 .TraverseStmt(BodyCtx.getTopStmt());
109 LocalRefsCollector(LocalRefs).TraverseStmt(BodyCtx.getTopStmt());
110
111 SourceRange BodyRange = BodyCtx.getTopStmt()->getSourceRange();
112 const CapturedDiagList &DiagList = Pass.getDiags();
113 // Copy the diagnostics so we don't have to worry about invaliding iterators
114 // from the diagnostic list.
115 SmallVector<StoredDiagnostic, 16> StoredDiags;
116 StoredDiags.append(DiagList.begin(), DiagList.end());
117 SmallVectorImpl<StoredDiagnostic>::iterator
118 I = StoredDiags.begin(), E = StoredDiags.end();
119 while (I != E) {
120 if (I->getID() == diag::err_switch_into_protected_scope &&
121 isInRange(I->getLocation(), BodyRange)) {
122 handleProtectedScopeError(I, E);
123 continue;
124 }
125 ++I;
126 }
127 }
128
handleProtectedScopeError(SmallVectorImpl<StoredDiagnostic>::iterator & DiagI,SmallVectorImpl<StoredDiagnostic>::iterator DiagE)129 void handleProtectedScopeError(
130 SmallVectorImpl<StoredDiagnostic>::iterator &DiagI,
131 SmallVectorImpl<StoredDiagnostic>::iterator DiagE){
132 Transaction Trans(Pass.TA);
133 assert(DiagI->getID() == diag::err_switch_into_protected_scope);
134 SourceLocation ErrLoc = DiagI->getLocation();
135 bool handledAllNotes = true;
136 ++DiagI;
137 for (; DiagI != DiagE && DiagI->getLevel() == DiagnosticsEngine::Note;
138 ++DiagI) {
139 if (!handleProtectedNote(*DiagI))
140 handledAllNotes = false;
141 }
142
143 if (handledAllNotes)
144 Pass.TA.clearDiagnostic(diag::err_switch_into_protected_scope, ErrLoc);
145 }
146
handleProtectedNote(const StoredDiagnostic & Diag)147 bool handleProtectedNote(const StoredDiagnostic &Diag) {
148 assert(Diag.getLevel() == DiagnosticsEngine::Note);
149
150 for (unsigned i = 0; i != Cases.size(); i++) {
151 CaseInfo &info = Cases[i];
152 if (isInRange(Diag.getLocation(), info.Range)) {
153
154 if (info.State == CaseInfo::St_Unchecked)
155 tryFixing(info);
156 assert(info.State != CaseInfo::St_Unchecked);
157
158 if (info.State == CaseInfo::St_Fixed) {
159 Pass.TA.clearDiagnostic(Diag.getID(), Diag.getLocation());
160 return true;
161 }
162 return false;
163 }
164 }
165
166 return false;
167 }
168
tryFixing(CaseInfo & info)169 void tryFixing(CaseInfo &info) {
170 assert(info.State == CaseInfo::St_Unchecked);
171 if (hasVarReferencedOutside(info)) {
172 info.State = CaseInfo::St_CannotFix;
173 return;
174 }
175
176 Pass.TA.insertAfterToken(info.SC->getColonLoc(), " {");
177 Pass.TA.insert(info.Range.getEnd(), "}\n");
178 info.State = CaseInfo::St_Fixed;
179 }
180
hasVarReferencedOutside(CaseInfo & info)181 bool hasVarReferencedOutside(CaseInfo &info) {
182 for (unsigned i = 0, e = LocalRefs.size(); i != e; ++i) {
183 DeclRefExpr *DRE = LocalRefs[i];
184 if (isInRange(DRE->getDecl()->getLocation(), info.Range) &&
185 !isInRange(DRE->getLocation(), info.Range))
186 return true;
187 }
188 return false;
189 }
190
isInRange(SourceLocation Loc,SourceRange R)191 bool isInRange(SourceLocation Loc, SourceRange R) {
192 if (Loc.isInvalid())
193 return false;
194 return !SM.isBeforeInTranslationUnit(Loc, R.getBegin()) &&
195 SM.isBeforeInTranslationUnit(Loc, R.getEnd());
196 }
197 };
198
199 } // anonymous namespace
200
traverseBody(BodyContext & BodyCtx)201 void ProtectedScopeTraverser::traverseBody(BodyContext &BodyCtx) {
202 ProtectedScopeFixer Fix(BodyCtx);
203 }
204