[arcmt] Adds brackets in case statements that "contain" initialization of retaining

variable, thus emitting the "switch case is in protected scope" error.

rdar://12952016

llvm-svn: 171484

1 files changed, 118 insertions, 0 deletions

diff --git a/clang/lib/ARCMigrate/TransProtectedScope.cpp b/clang/lib/ARCMigrate/TransProtectedScope.cpp
new file mode 100644
index 00000000000..b2026006256
--- /dev/null
+++ b/clang/lib/ARCMigrate/TransProtectedScope.cpp
@@ -0,0 +1,118 @@
+//===--- TransProtectedScope.cpp - Transformations to ARC mode ------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Adds brackets in case statements that "contain" initialization of retaining
+// variable, thus emitting the "switch case is in protected scope" error.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Transforms.h"
+#include "Internals.h"
+#include "clang/Sema/SemaDiagnostic.h"
+
+using namespace clang;
+using namespace arcmt;
+using namespace trans;
+
+namespace {
+
+struct CaseInfo {
+  SwitchCase *SC;
+  SourceRange Range;
+  bool FixedBypass;
+  
+  CaseInfo() : SC(0), FixedBypass(false) {}
+  CaseInfo(SwitchCase *S, SourceRange Range)
+    : SC(S), Range(Range), FixedBypass(false) {}
+};
+
+class CaseCollector : public RecursiveASTVisitor<CaseCollector> {
+  llvm::SmallVectorImpl<CaseInfo> &Cases;
+
+public:
+  CaseCollector(llvm::SmallVectorImpl<CaseInfo> &Cases)
+    : Cases(Cases) { }
+
+  bool VisitSwitchStmt(SwitchStmt *S) {
+    SourceLocation NextLoc = S->getLocEnd();
+    SwitchCase *Curr = S->getSwitchCaseList();
+    // We iterate over case statements in reverse source-order.
+    while (Curr) {
+      Cases.push_back(CaseInfo(Curr,SourceRange(Curr->getLocStart(), NextLoc)));
+      NextLoc = Curr->getLocStart();
+      Curr = Curr->getNextSwitchCase();
+    }
+    return true;
+  }
+};
+
+} // anonymous namespace
+
+static bool isInRange(FullSourceLoc Loc, SourceRange R) {
+  return !Loc.isBeforeInTranslationUnitThan(R.getBegin()) &&
+          Loc.isBeforeInTranslationUnitThan(R.getEnd());
+}
+
+static bool handleProtectedNote(const StoredDiagnostic &Diag,
+                                llvm::SmallVectorImpl<CaseInfo> &Cases,
+                                TransformActions &TA) {
+  assert(Diag.getLevel() == DiagnosticsEngine::Note);
+
+  for (unsigned i = 0; i != Cases.size(); i++) {
+    CaseInfo &info = Cases[i];
+    if (isInRange(Diag.getLocation(), info.Range)) {
+      TA.clearDiagnostic(Diag.getID(), Diag.getLocation());
+      if (!info.FixedBypass) {
+        TA.insertAfterToken(info.SC->getColonLoc(), " {");
+        TA.insert(info.Range.getEnd(), "}\n");
+        info.FixedBypass = true;
+      }
+      return true;
+    }
+  }
+
+  return false;
+}
+
+static void handleProtectedScopeError(CapturedDiagList::iterator &DiagI,
+                                      CapturedDiagList::iterator DiagE,
+                                      llvm::SmallVectorImpl<CaseInfo> &Cases,
+                                      TransformActions &TA) {
+  Transaction Trans(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, Cases, TA))
+      handledAllNotes = false;
+  }
+
+  if (handledAllNotes)
+    TA.clearDiagnostic(diag::err_switch_into_protected_scope, ErrLoc);
+}
+
+void ProtectedScopeTraverser::traverseBody(BodyContext &BodyCtx) {
+  MigrationPass &Pass = BodyCtx.getMigrationContext().Pass;
+  SmallVector<CaseInfo, 16> Cases;
+  CaseCollector(Cases).TraverseStmt(BodyCtx.getTopStmt());
+
+  SourceRange BodyRange = BodyCtx.getTopStmt()->getSourceRange();
+  const CapturedDiagList &DiagList = Pass.getDiags();
+  CapturedDiagList::iterator I = DiagList.begin(), E = DiagList.end();
+  while (I != E) {
+    if (I->getID() == diag::err_switch_into_protected_scope &&
+        isInRange(I->getLocation(), BodyRange)) {
+      handleProtectedScopeError(I, E, Cases, Pass.TA);
+      continue;
+    }
+    ++I;
+  }
+}