for (CFGBlock::const_reverse_iterator I = B->rbegin(), E = B->rend();
I != E; ++I) {
if (Optional<CFGStmt> CS = I->getAs<CFGStmt>()) {
- if (const CallExpr *CE = dyn_cast<CallExpr>(CS->getStmt())) {
+ const Stmt *S = CS->getStmt();
+ if (const ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(S))
+ S = EWC->getSubExpr();
+ if (const CallExpr *CE = dyn_cast<CallExpr>(S)) {
QualType CalleeType = CE->getCallee()->getType();
if (getFunctionExtInfo(*CalleeType).getNoReturn())
return true;
return isa<EnumConstantDecl>(DR->getDecl());
}
+static const Expr *stripStdStringCtor(const Expr *Ex) {
+ // Go crazy pattern matching an implicit construction of std::string("").
+ const ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(Ex);
+ if (!EWC)
+ return 0;
+ const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(EWC->getSubExpr());
+ if (!CCE)
+ return 0;
+ QualType Ty = CCE->getType();
+ if (const ElaboratedType *ET = dyn_cast<ElaboratedType>(Ty))
+ Ty = ET->getNamedType();
+ const TypedefType *TT = dyn_cast<TypedefType>(Ty);
+ StringRef Name = TT->getDecl()->getName();
+ if (Name != "string")
+ return 0;
+ if (CCE->getNumArgs() != 1)
+ return 0;
+ const MaterializeTemporaryExpr *MTE =
+ dyn_cast<MaterializeTemporaryExpr>(CCE->getArg(0));
+ if (!MTE)
+ return 0;
+ CXXBindTemporaryExpr *CBT =
+ dyn_cast<CXXBindTemporaryExpr>(MTE->GetTemporaryExpr()->IgnoreParenCasts());
+ if (!CBT)
+ return 0;
+ Ex = CBT->getSubExpr()->IgnoreParenCasts();
+ CCE = dyn_cast<CXXConstructExpr>(Ex);
+ if (!CCE)
+ return 0;
+ if (CCE->getNumArgs() != 1)
+ return 0;
+ return dyn_cast<StringLiteral>(CCE->getArg(0)->IgnoreParenCasts());
+}
+
+/// Strip away "sugar" around trivial expressions that are for the
+/// purpose of this analysis considered uninteresting for dead code warnings.
+static const Expr *stripExprSugar(const Expr *Ex) {
+ Ex = Ex->IgnoreParenCasts();
+ // If 'Ex' is a constructor for a std::string, strip that
+ // away. We can only get here if the trivial expression was
+ // something like a C string literal, with the std::string
+ // just wrapping that value.
+ if (const Expr *StdStringVal = stripStdStringCtor(Ex))
+ return StdStringVal;
+ return Ex;
+}
+
static bool isTrivialExpression(const Expr *Ex) {
Ex = Ex->IgnoreParenCasts();
return isa<IntegerLiteral>(Ex) || isa<StringLiteral>(Ex) ||
if (Optional<CFGStmt> CS = I->getAs<CFGStmt>()) {
if (const ReturnStmt *RS = dyn_cast<ReturnStmt>(CS->getStmt())) {
const Expr *RE = RS->getRetValue();
- if (RE && RE->IgnoreParenCasts() == Ex)
+ if (RE && stripExprSugar(RE->IgnoreParenCasts()) == Ex)
return bodyEndsWithNoReturn(*B->pred_begin());
}
break;