Author: David Goldman
Date: 2020-07-24T17:02:06-04:00
New Revision: 3c1fca803bc14617b67ba2125e1b4b77190e9f86
URL:
https://github.com/llvm/llvm-project/commit/3c1fca803bc14617b67ba2125e1b4b77190e9f86
DIFF:
https://github.com/llvm/llvm-project/commit/3c1fca803bc14617b67ba2125e1b4b77190e9f86.diff
LOG: Fix issue in typo handling which could lead clang to hang
Summary:
We need to detect when certain TypoExprs are not being transformed
due to invalid trees, otherwise we risk endlessly trying to fix it.
Reviewers: rsmith
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D84067
(cherry picked from commit dde98c82c0ad02410229e7e5c9efcbb0ab42a995)
Added:
clang/test/Sema/typo-correction-no-hang.cpp
Modified:
clang/include/clang/Sema/SemaInternal.h
clang/lib/Sema/SemaExprCXX.cpp
clang/test/Sema/typo-correction-recursive.cpp
Removed:
diff --git a/clang/include/clang/Sema/SemaInternal.h
b/clang/include/clang/Sema/SemaInternal.h
index cdaf7b70a92f..842eec099540 100644
--- a/clang/include/clang/Sema/SemaInternal.h
+++ b/clang/include/clang/Sema/SemaInternal.h
@@ -168,6 +168,11 @@ class TypoCorrectionConsumer : public VisibleDeclConsumer {
return TC;
}
+ /// In the case of deeply invalid expressions, `getNextCorrection()` will
+ /// never be called since the transform never makes progress. If we don't
+ /// detect this we risk trying to correct typos forever.
+ bool hasMadeAnyCorrectionProgress() const { return CurrentTCIndex != 0; }
+
/// Reset the consumer's position in the stream of viable corrections
/// (i.e. getNextCorrection() will return each of the previously returned
/// corrections in order before returning any new corrections).
diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index d885920b6c14..77bd1ab360b2 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -7977,19 +7977,26 @@ class TransformTypos : public
TreeTransform {
}
}
- /// If corrections for the first TypoExpr have been exhausted for a
- /// given combination of the other TypoExprs, retry those corrections against
- /// the next combination of substitutions for the other TypoExprs by
advancing
- /// to the next potential correction of the second TypoExpr. For the second
- /// and subsequent TypoExprs, if its stream of corrections has been
exhausted,
- /// the stream is reset and the next TypoExpr's stream is advanced by one (a
- /// TypoExpr's correction stream is advanced by removing the TypoExpr from
the
- /// TransformCache). Returns true if there is still any untried combinations
- /// of corrections.
+ /// Try to advance the typo correction state of the first unfinished
TypoExpr.
+ /// We allow advancement of the correction stream by removing it from the
+ /// TransformCache which allows `TransformTypoExpr` to advance during the
+ /// next transformation attempt.
+ ///
+ /// Any substitution attempts for the previous TypoExprs (which must have
been
+ /// finished) will need to be retried since it's possible that they will now
+ /// be invalid given the latest advancement.
+ ///
+ /// We need to be sure that we're making progress - it's possible that the
+ /// tree is so malformed that the transform never makes it to the
+ /// `TransformTypoExpr`.
+ ///
+ /// Returns true if there are any untried correction combinations.
bool CheckAndAdvanceTypoExprCorrectionStreams() {
for (auto TE : TypoExprs) {
auto &State = SemaRef.getTypoExprState(TE);
TransformCache.erase(TE);
+ if (!State.Consumer->hasMadeAnyCorrectionProgress())
+return false;
if (!State.Consumer->finished())
return true;
State.Consumer->resetCorrectionStream();
diff --git a/clang/test/Sema/typo-correction-no-hang.cpp
b/clang/test/Sema/typo-correction-no-hang.cpp
new file mode 100644
index ..3c591645be25
--- /dev/null
+++ b/clang/test/Sema/typo-correction-no-hang.cpp
@@ -0,0 +1,40 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+// From `test/Sema/typo-correction.c` but for C++ since the behavior varies
+// between the two languages.
+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'}}
+}
+
+// Similar reproducer.
+class A {
+public:
+ int minut() const = delete;
+ int hour() const = delete;
+
+ int longit() const; //expected-note{{'longit' declared here}}
+ int latit() const;
+};
+
+class B {
+public:
+ A depar() const { return A(); }
+};
+
+int Foo(const B &b) {
+ return b.deparT().hours() * 60 + //expected-
