Add an implicit dtor CFG node just before C++ 'delete' expressions.

This paves the way for adding support for modeling the destructor of a
region before it is deleted. The statement "delete <expr>" now generates
this series of CFG elements:

  1. <expr>
  2. [B1.1]->~Foo() (Implicit destructor)
  3. delete [B1.1]

Patch by Karthik Bhat!

llvm-svn: 189828

1 files changed, 41 insertions, 0 deletions

diff --git a/clang/lib/Analysis/CFG.cpp b/clang/lib/Analysis/CFG.cpp
index ad0acb7abe5..5e03f4377d3 100644
--- a/clang/lib/Analysis/CFG.cpp
+++ b/clang/lib/Analysis/CFG.cpp
@@ -363,6 +363,7 @@ private:
                                       AddStmtChoice asc);
   CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S);
   CFGBlock *VisitCXXConstructExpr(CXXConstructExpr *C, AddStmtChoice asc);
+  CFGBlock *VisitCXXDeleteExpr(CXXDeleteExpr *DE, AddStmtChoice asc);
   CFGBlock *VisitCXXForRangeStmt(CXXForRangeStmt *S);
   CFGBlock *VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
                                        AddStmtChoice asc);
@@ -471,6 +472,10 @@ private:
     B->appendAutomaticObjDtor(VD, S, cfg->getBumpVectorContext());
   }
 
+  void appendDeleteDtor(CFGBlock *B, CXXRecordDecl *RD, CXXDeleteExpr *DE) {
+    B->appendDeleteDtor(RD, DE, cfg->getBumpVectorContext());
+  }
+
   void prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk,
       LocalScope::const_iterator B, LocalScope::const_iterator E);
 
@@ -1117,6 +1122,9 @@ CFGBlock *CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) {
     case Stmt::CXXConstructExprClass:
       return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc);
 
+    case Stmt::CXXDeleteExprClass:
+      return VisitCXXDeleteExpr(cast<CXXDeleteExpr>(S), asc);
+
     case Stmt::CXXFunctionalCastExprClass:
       return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc);
 
@@ -3113,6 +3121,22 @@ CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C,
   return VisitChildren(C);
 }
 
+
+CFGBlock *CFGBuilder::VisitCXXDeleteExpr(CXXDeleteExpr *DE,
+                                         AddStmtChoice asc) {
+  autoCreateBlock();
+  appendStmt(Block, DE);
+  QualType DTy = DE->getDestroyedType();
+  DTy = DTy.getNonReferenceType();
+  CXXRecordDecl *RD = Context->getBaseElementType(DTy)->getAsCXXRecordDecl();
+  if (RD) {
+    if (!RD->hasTrivialDestructor())
+      appendDeleteDtor(Block, RD, DE);
+  }
+
+  return VisitChildren(DE);
+}
+
 CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
                                                  AddStmtChoice asc) {
   if (asc.alwaysAdd(*this, E)) {
@@ -3413,6 +3437,14 @@ CFGImplicitDtor::getDestructorDecl(ASTContext &astContext) const {
       cast<CXXRecordDecl>(recordType->getDecl());
       return classDecl->getDestructor();      
     }
+    case CFGElement::DeleteDtor: {
+      const CXXDeleteExpr *DE = castAs<CFGDeleteDtor>().getDeleteExpr();
+      QualType DTy = DE->getDestroyedType();
+      DTy = DTy.getNonReferenceType();
+      const CXXRecordDecl *classDecl =
+          astContext.getBaseElementType(DTy)->getAsCXXRecordDecl();
+      return classDecl->getDestructor();
+    }
     case CFGElement::TemporaryDtor: {
       const CXXBindTemporaryExpr *bindExpr =
         castAs<CFGTemporaryDtor>().getBindTemporaryExpr();
@@ -3751,6 +3783,15 @@ static void print_elem(raw_ostream &OS, StmtPrinterHelper* Helper,
     OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()";
     OS << " (Implicit destructor)\n";
 
+  } else if (Optional<CFGDeleteDtor> DE = E.getAs<CFGDeleteDtor>()) {
+    const CXXRecordDecl *RD = DE->getCXXRecordDecl();
+    if (!RD)
+      return;
+    CXXDeleteExpr *DelExpr =
+        const_cast<CXXDeleteExpr*>(DE->getDeleteExpr());
+    Helper->handledStmt(cast<Stmt>(DelExpr->getArgument()), OS);
+    OS << "->~" << RD->getName().str() << "()";
+    OS << " (Implicit destructor)\n";
   } else if (Optional<CFGBaseDtor> BE = E.getAs<CFGBaseDtor>()) {
     const CXXBaseSpecifier *BS = BE->getBaseSpecifier();
     OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()";