On Thu, May 14, 2015 at 11:02 PM, Diego Novillo <dnovi...@google.com> wrote: > I've reverted this change for now (r237391). I am reducing the > original file. I hope to have a test case for you later > today/tomorrow. > > > Thanks. Diego. > > On Thu, May 14, 2015 at 3:20 PM, Diego Novillo <dnovi...@google.com> wrote: >> >> Ismail, >> >> I ran into a segfault inside the new warning you added in >> http://reviews.llvm.org/D4661. I don't have a repro case for you, but I'm >> in a debugging session now and this may help you (and me getting a test case >> for you). >> >> We die in >> >> clang: llvm/llvm/include/llvm/Support/Casting.h:95: static bool >> llvm::isa_impl_cl<const clang::CXXNewExpr, const clang::Expr *>::doit(const >> From *) [To = const clang::CXXNewExpr, From = const clang::Expr *]: >> Assertion `Val && "isa<> used on a null pointer"' failed. >> >> The issue starts in MismatchingNewDeleteDetector::analyzeInClassInitializer. >> The call to Field->getInClassInitializer() returns the expression: >> >> (gdb) call E->dump() >> InitListExpr 0x7ffff6cdf010 'class Cord *' >> `-ImplicitCastExpr 0x7ffff6cdf050 'class Cord *' <NullToPointer> >> `-CXXNullPtrLiteralExpr 0x7ffff6cdefb0 'nullptr_t' >> >> We then call MismatchingNewDeleteDetector::getNewExprFromInitListOrExpr() >> with that expression. The function checks that the initial expression is not >> null, but we then decide to get the first init from the list of inits, which >> returns a nullptr: >> >> 2451 if (ILE->getNumInits() == 1) >> (gdb) call ILE->dump() >> InitListExpr 0x7ffff6cdf010 'class Cord *' >> `-ImplicitCastExpr 0x7ffff6cdf050 'class Cord *' <NullToPointer> >> `-CXXNullPtrLiteralExpr 0x7ffff6cdefb0 'nullptr_t' >> (gdb) n >> 2452 E = dyn_cast<const >> CXXNewExpr>(ILE->getInit(0)->IgnoreParenImpCasts()); >> (gdb) n >> 2453 } >> (gdb) p E >> $6 = (const clang::Expr *) 0x0 >> >> Then we try to dyn_cast<> it, which segfaults: >> >> (gdb) n >> 2455 return dyn_cast<const CXXNewExpr>(E); >> (gdb) n >> clang: third_party/llvm/llvm/include/llvm/Support/Casting.h:95: static bool >> llvm::isa_impl_cl<const clang::CXXNewExpr, const clang::Expr *>::doit(const >> From *) [To = const clang::CXXNewExpr, From = const clang::Expr *]: >> Assertion `Val && "isa<> used on a null pointer"' failed. >> >> Program received signal SIGABRT, Aborted. >> >> >> >> I don't know whether we should just return nil when E gets nullfiied or this >> is a sign of some other problem. >> >> >> Thanks. Diego.
Thank you for detailed analysis, Diego! I was away last few hours. A reduced test case would be perfect. I will try it myself tomorrow, and hopefully fix it during the weekend. Ismail _______________________________________________ cfe-commits mailing list cfe-commits@cs.uiuc.edu http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
