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//===--- TransProtectedScope.cpp - Transformations to ARC mode ------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Adds brackets in case statements that "contain" initialization of retaining
// variable, thus emitting the "switch case is in protected scope" error.
//
//===----------------------------------------------------------------------===//
#include "Internals.h"
#include "Transforms.h"
#include "clang/AST/ASTContext.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Sema/SemaDiagnostic.h"
using namespace clang;
using namespace arcmt;
using namespace trans;
namespace {
class LocalRefsCollector : public RecursiveASTVisitor<LocalRefsCollector> {
SmallVectorImpl<DeclRefExpr *> &Refs;
public:
LocalRefsCollector(SmallVectorImpl<DeclRefExpr *> &refs)
: Refs(refs) { }
bool VisitDeclRefExpr(DeclRefExpr *E) {
if (ValueDecl *D = E->getDecl())
if (D->getDeclContext()->getRedeclContext()->isFunctionOrMethod())
Refs.push_back(E);
return true;
}
};
struct CaseInfo {
SwitchCase *SC;
SourceRange Range;
enum {
St_Unchecked,
St_CannotFix,
St_Fixed
} State;
CaseInfo() : SC(nullptr), State(St_Unchecked) {}
CaseInfo(SwitchCase *S, SourceRange Range)
: SC(S), Range(Range), State(St_Unchecked) {}
};
class CaseCollector : public RecursiveASTVisitor<CaseCollector> {
ParentMap &PMap;
SmallVectorImpl<CaseInfo> &Cases;
public:
CaseCollector(ParentMap &PMap, SmallVectorImpl<CaseInfo> &Cases)
: PMap(PMap), Cases(Cases) { }
bool VisitSwitchStmt(SwitchStmt *S) {
SwitchCase *Curr = S->getSwitchCaseList();
if (!Curr)
return true;
Stmt *Parent = getCaseParent(Curr);
Curr = Curr->getNextSwitchCase();
// Make sure all case statements are in the same scope.
while (Curr) {
if (getCaseParent(Curr) != Parent)
return true;
Curr = Curr->getNextSwitchCase();
}
SourceLocation NextLoc = S->getEndLoc();
Curr = S->getSwitchCaseList();
// We iterate over case statements in reverse source-order.
while (Curr) {
Cases.push_back(
CaseInfo(Curr, SourceRange(Curr->getBeginLoc(), NextLoc)));
NextLoc = Curr->getBeginLoc();
Curr = Curr->getNextSwitchCase();
}
return true;
}
Stmt *getCaseParent(SwitchCase *S) {
Stmt *Parent = PMap.getParent(S);
while (Parent && (isa<SwitchCase>(Parent) || isa<LabelStmt>(Parent)))
Parent = PMap.getParent(Parent);
return Parent;
}
};
class ProtectedScopeFixer {
MigrationPass &Pass;
SourceManager &SM;
SmallVector<CaseInfo, 16> Cases;
SmallVector<DeclRefExpr *, 16> LocalRefs;
public:
ProtectedScopeFixer(BodyContext &BodyCtx)
: Pass(BodyCtx.getMigrationContext().Pass),
SM(Pass.Ctx.getSourceManager()) {
CaseCollector(BodyCtx.getParentMap(), Cases)
.TraverseStmt(BodyCtx.getTopStmt());
LocalRefsCollector(LocalRefs).TraverseStmt(BodyCtx.getTopStmt());
SourceRange BodyRange = BodyCtx.getTopStmt()->getSourceRange();
const CapturedDiagList &DiagList = Pass.getDiags();
// Copy the diagnostics so we don't have to worry about invaliding iterators
// from the diagnostic list.
SmallVector<StoredDiagnostic, 16> StoredDiags;
StoredDiags.append(DiagList.begin(), DiagList.end());
SmallVectorImpl<StoredDiagnostic>::iterator
I = StoredDiags.begin(), E = StoredDiags.end();
while (I != E) {
if (I->getID() == diag::err_switch_into_protected_scope &&
isInRange(I->getLocation(), BodyRange)) {
handleProtectedScopeError(I, E);
continue;
}
++I;
}
}
void handleProtectedScopeError(
SmallVectorImpl<StoredDiagnostic>::iterator &DiagI,
SmallVectorImpl<StoredDiagnostic>::iterator DiagE){
Transaction Trans(Pass.TA);
assert(DiagI->getID() == diag::err_switch_into_protected_scope);
SourceLocation ErrLoc = DiagI->getLocation();
bool handledAllNotes = true;
++DiagI;
for (; DiagI != DiagE && DiagI->getLevel() == DiagnosticsEngine::Note;
++DiagI) {
if (!handleProtectedNote(*DiagI))
handledAllNotes = false;
}
if (handledAllNotes)
Pass.TA.clearDiagnostic(diag::err_switch_into_protected_scope, ErrLoc);
}
bool handleProtectedNote(const StoredDiagnostic &Diag) {
assert(Diag.getLevel() == DiagnosticsEngine::Note);
for (unsigned i = 0; i != Cases.size(); i++) {
CaseInfo &info = Cases[i];
if (isInRange(Diag.getLocation(), info.Range)) {
if (info.State == CaseInfo::St_Unchecked)
tryFixing(info);
assert(info.State != CaseInfo::St_Unchecked);
if (info.State == CaseInfo::St_Fixed) {
Pass.TA.clearDiagnostic(Diag.getID(), Diag.getLocation());
return true;
}
return false;
}
}
return false;
}
void tryFixing(CaseInfo &info) {
assert(info.State == CaseInfo::St_Unchecked);
if (hasVarReferencedOutside(info)) {
info.State = CaseInfo::St_CannotFix;
return;
}
Pass.TA.insertAfterToken(info.SC->getColonLoc(), " {");
Pass.TA.insert(info.Range.getEnd(), "}\n");
info.State = CaseInfo::St_Fixed;
}
bool hasVarReferencedOutside(CaseInfo &info) {
for (unsigned i = 0, e = LocalRefs.size(); i != e; ++i) {
DeclRefExpr *DRE = LocalRefs[i];
if (isInRange(DRE->getDecl()->getLocation(), info.Range) &&
!isInRange(DRE->getLocation(), info.Range))
return true;
}
return false;
}
bool isInRange(SourceLocation Loc, SourceRange R) {
if (Loc.isInvalid())
return false;
return !SM.isBeforeInTranslationUnit(Loc, R.getBegin()) &&
SM.isBeforeInTranslationUnit(Loc, R.getEnd());
}
};
} // anonymous namespace
void ProtectedScopeTraverser::traverseBody(BodyContext &BodyCtx) {
ProtectedScopeFixer Fix(BodyCtx);
}
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