Teach CFG building how to deal with CXXMemberCallExprs and BoundMemberTy,

then teach -Wreturn-type to handle the same.  Net effect:  we now correctly
handle noreturn attributes on member calls in the CFG.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@131178 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Analysis/CFG.cpp

@@ -320,7 +320,6 @@ private:
                                        AddStmtChoice asc);
   CFGBlock *VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 
                                         AddStmtChoice asc);
-  CFGBlock *VisitCXXMemberCallExpr(CXXMemberCallExpr *C, AddStmtChoice asc);
   CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc);
   CFGBlock *VisitCaseStmt(CaseStmt *C);
   CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc);
@@ -868,6 +867,7 @@ tryAgain:
 
     case Stmt::CallExprClass:
     case Stmt::CXXOperatorCallExprClass:
+    case Stmt::CXXMemberCallExprClass:
       return VisitCallExpr(cast<CallExpr>(S), asc);
 
     case Stmt::CaseStmtClass:
@@ -903,9 +903,6 @@ tryAgain:
     case Stmt::CXXTemporaryObjectExprClass:
       return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc);
 
-    case Stmt::CXXMemberCallExprClass:
-      return VisitCXXMemberCallExpr(cast<CXXMemberCallExpr>(S), asc);
-
     case Stmt::CXXThrowExprClass:
       return VisitCXXThrowExpr(cast<CXXThrowExpr>(S));
 
@@ -1153,12 +1150,19 @@ static bool CanThrow(Expr *E, ASTContext &Ctx) {
 }
 
 CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) {
-  // If this is a call to a no-return function, this stops the block here.
-  bool NoReturn = false;
-  if (getFunctionExtInfo(*C->getCallee()->getType()).getNoReturn()) {
-    NoReturn = true;
+  // Compute the callee type.
+  QualType calleeType = C->getCallee()->getType();
+  if (calleeType == Context->BoundMemberTy) {
+    QualType boundType = Expr::findBoundMemberType(C->getCallee());
+
+    // We should only get a null bound type if processing a dependent
+    // CFG.  Recover by assuming nothing.
+    if (!boundType.isNull()) calleeType = boundType;
   }
 
+  // If this is a call to a no-return function, this stops the block here.
+  bool NoReturn = getFunctionExtInfo(*calleeType).getNoReturn();
+
   bool AddEHEdge = false;
 
   // Languages without exceptions are assumed to not throw.
@@ -2691,13 +2695,6 @@ CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C,
   return VisitChildren(C);
 }
 
-CFGBlock *CFGBuilder::VisitCXXMemberCallExpr(CXXMemberCallExpr *C,
-                                             AddStmtChoice asc) {
-  autoCreateBlock();
-  appendStmt(Block, C);
-  return VisitChildren(C);
-}
-
 CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E,
                                             AddStmtChoice asc) {
   if (asc.alwaysAdd(*this, E)) {

lib/Sema/AnalysisBasedWarnings.cpp

@@ -196,7 +196,12 @@ static ControlFlowKind CheckFallThrough(AnalysisContext &AC) {
         continue;
       }
       Expr *CEE = C->getCallee()->IgnoreParenCasts();
-      if (getFunctionExtInfo(CEE->getType()).getNoReturn()) {
+      QualType calleeType = CEE->getType();
+      if (calleeType == AC.getASTContext().BoundMemberTy) {
+        calleeType = Expr::findBoundMemberType(CEE);
+        assert(!calleeType.isNull() && "analyzing unresolved call?");
+      }
+      if (getFunctionExtInfo(calleeType).getNoReturn()) {
         NoReturnEdge = true;
         HasFakeEdge = true;
       } else if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(CEE)) {

test/SemaCXX/attr-noreturn.cpp

 // RUN: %clang_cc1 -fsyntax-only -verify %s
 
+// Reachability tests have to come first because they get suppressed
+// if any errors have occurred.
+namespace test5 {
+  struct A {
+    __attribute__((noreturn)) void fail();
+    void nofail();
+  } a;
+
+  int &test1() {
+    a.nofail();
+  } // expected-warning {{control reaches end of non-void function}}
+
+  int &test2() {
+    a.fail();
+  }
+}
+
 // PR5620
 void f0() __attribute__((__noreturn__));
 void f1(void (*)());