From: Volodymyr Sapsai <vsapsai@apple.com>
Date: Tue, 26 Jun 2018 17:56:48 +0000 (+0000)
Subject: [Sema] Fix infinite typo correction loop.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=4d1c54646bd2e3bcb05ff96c7373f1069aed9f9a;p=clang

[Sema] Fix infinite typo correction loop.

NumTypos guard value ~0U doesn't prevent from creating new delayed typos. When
you create new delayed typos during typo correction, value ~0U wraps around to
0. When NumTypos is 0 we can miss some typos and treat an expression as it can
be typo-corrected. But if the expression is still invalid after correction, we
can get stuck in infinite loop trying to correct it.

Fix by not using value ~0U so that NumTypos correctly reflects the number of
typos.

rdar://problem/38642201

Reviewers: arphaman, majnemer, rsmith

Reviewed By: rsmith

Subscribers: rsmith, nicholas, cfe-commits

Differential Revision: https://reviews.llvm.org/D47341



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@335638 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Sema/SemaExprCXX.cpp b/lib/Sema/SemaExprCXX.cpp
index 59066ee34f..02cb78b9de 100644
--- a/lib/Sema/SemaExprCXX.cpp
+++ b/lib/Sema/SemaExprCXX.cpp
@@ -7727,12 +7727,8 @@ Sema::CorrectDelayedTyposInExpr(Expr *E, VarDecl *InitDecl,
   if (E && !ExprEvalContexts.empty() && ExprEvalContexts.back().NumTypos &&
       (E->isTypeDependent() || E->isValueDependent() ||
        E->isInstantiationDependent())) {
-    auto TyposInContext = ExprEvalContexts.back().NumTypos;
-    assert(TyposInContext < ~0U && "Recursive call of CorrectDelayedTyposInExpr");
-    ExprEvalContexts.back().NumTypos = ~0U;
     auto TyposResolved = DelayedTypos.size();
     auto Result = TransformTypos(*this, InitDecl, Filter).Transform(E);
-    ExprEvalContexts.back().NumTypos = TyposInContext;
     TyposResolved -= DelayedTypos.size();
     if (Result.isInvalid() || Result.get() != E) {
       ExprEvalContexts.back().NumTypos -= TyposResolved;
diff --git a/test/Sema/typo-correction.c b/test/Sema/typo-correction.c
index 78007015dc..e7992ac90b 100644
--- a/test/Sema/typo-correction.c
+++ b/test/Sema/typo-correction.c
@@ -87,3 +87,16 @@ __attribute__((overloadable)) void func_overloadable(float);
 void overloadable_callexpr(int arg) {
 	func_overloadable(ar); //expected-error{{use of undeclared identifier}}
 }
+
+// rdar://problem/38642201
+struct rdar38642201 {
+  int fieldName;
+};
+
+void rdar38642201_callee(int x, int y);
+void rdar38642201_caller() {
+  struct rdar38642201 structVar;
+  rdar38642201_callee(
+      structVar1.fieldName1.member1, //expected-error{{use of undeclared identifier 'structVar1'}}
+      structVar2.fieldName2.member2); //expected-error{{use of undeclared identifier 'structVar2'}}
+}