CFG: Add CFGElement for automatic variables that leave the scope

Summary:
This mimics the implementation for the implicit destructors. The
generation of this scope leaving elements is hidden behind
a flag to the CFGBuilder, thus it should not affect existing code.

Currently, I'm missing a test (it's implicitly tested by the clang-tidy
lifetime checker that I'm proposing).
I though about a test using debug.DumpCFG, but then I would
have to add an option to StaticAnalyzer/Core/AnalyzerOptions
to enable the scope leaving CFGElement,
which would only be useful to that particular test.

Any other ideas how I could make a test for this feature?

Reviewers: krememek, jordan_rose

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D15031

llvm-svn: 307759

4 files changed, 16 insertions, 1 deletions

diff --git a/clang/lib/StaticAnalyzer/Core/AnalysisManager.cpp b/clang/lib/StaticAnalyzer/Core/AnalysisManager.cpp
index 54634fdffeb..83e67662e61 100644
--- a/clang/lib/StaticAnalyzer/Core/AnalysisManager.cpp
+++ b/clang/lib/StaticAnalyzer/Core/AnalysisManager.cpp
@@ -23,9 +23,10 @@ AnalysisManager::AnalysisManager(ASTContext &ctx, DiagnosticsEngine &diags,
                                  AnalyzerOptions &Options,
                                  CodeInjector *injector)
   : AnaCtxMgr(Options.UnoptimizedCFG,
-              /*AddImplicitDtors=*/true,
+              Options.includeImplicitDtorsInCFG(),
               /*AddInitializers=*/true,
               Options.includeTemporaryDtorsInCFG(),
+	      Options.includeLifetimeInCFG(),
               Options.shouldSynthesizeBodies(),
               Options.shouldConditionalizeStaticInitializers(),
               /*addCXXNewAllocator=*/true,
diff --git a/clang/lib/StaticAnalyzer/Core/AnalyzerOptions.cpp b/clang/lib/StaticAnalyzer/Core/AnalyzerOptions.cpp
index 11b9f8c4f72..6f48fcb9e20 100644
--- a/clang/lib/StaticAnalyzer/Core/AnalyzerOptions.cpp
+++ b/clang/lib/StaticAnalyzer/Core/AnalyzerOptions.cpp
@@ -172,6 +172,17 @@ bool AnalyzerOptions::includeTemporaryDtorsInCFG() {
                           /* Default = */ false);
 }
 
+bool AnalyzerOptions::includeImplicitDtorsInCFG() {
+  return getBooleanOption(IncludeImplicitDtorsInCFG,
+                          "cfg-implicit-dtors",
+                          /* Default = */ true);
+}
+
+bool AnalyzerOptions::includeLifetimeInCFG() {
+  return getBooleanOption(IncludeLifetimeInCFG, "cfg-lifetime",
+                          /* Default = */ false);
+}
+
 bool AnalyzerOptions::mayInlineCXXStandardLibrary() {
   return getBooleanOption(InlineCXXStandardLibrary,
                           "c++-stdlib-inlining",
diff --git a/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp b/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
index f84c0ee800a..eee5400fe17 100644
--- a/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
+++ b/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
@@ -362,6 +362,8 @@ void ExprEngine::processCFGElement(const CFGElement E, ExplodedNode *Pred,
     case CFGElement::TemporaryDtor:
       ProcessImplicitDtor(E.castAs<CFGImplicitDtor>(), Pred);
       return;
+    case CFGElement::LifetimeEnds:
+      return;
   }
 }
 
diff --git a/clang/lib/StaticAnalyzer/Core/PathDiagnostic.cpp b/clang/lib/StaticAnalyzer/Core/PathDiagnostic.cpp
index 6aa6da560e6..d91786f7491 100644
--- a/clang/lib/StaticAnalyzer/Core/PathDiagnostic.cpp
+++ b/clang/lib/StaticAnalyzer/Core/PathDiagnostic.cpp
@@ -578,6 +578,7 @@ getLocationForCaller(const StackFrameContext *SFC,
   }
   case CFGElement::TemporaryDtor:
   case CFGElement::NewAllocator:
+  case CFGElement::LifetimeEnds:
     llvm_unreachable("not yet implemented!");
   }