[clang] bb764ec - [Clang] Fix CXXRewrittenBinaryOperator::getDecomposedForm to handle case when spaceship operator returns comparison category by reference (#66270)

[via cfe-commits]

Author: Shafik Yaghmour
Date: 2023-09-25T13:08:10-07:00
New Revision: bb764eccf8053244d64270df29c2e0bd3606f6c0

URL: https://github.com/llvm/llvm-project/commit/bb764eccf8053244d64270df29c2e0bd3606f6c0
DIFF: https://github.com/llvm/llvm-project/commit/bb764eccf8053244d64270df29c2e0bd3606f6c0.diff

LOG: [Clang] Fix CXXRewrittenBinaryOperator::getDecomposedForm to handle case when spaceship operator returns comparison category by reference (#66270)

Currently CXXRewrittenBinaryOperator::getDecomposedForm(...) may crash
if the spaceship operator returns a comparison category by reference. This
because IgnoreImplicitAsWritten() does not look through CXXConstructExpr. The
fix is to use IgnoreUnlessSpelledInSource() which will look though
CXXConstructExpr.

This fixes: https://github.com/llvm/llvm-project/issues/64162

Added: 
    

Modified: 
    clang/docs/ReleaseNotes.rst
    clang/lib/AST/ExprCXX.cpp
    clang/test/SemaCXX/compare-cxx2a.cpp

Removed: 
    


################################################################################
diff  --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 294b77a3e260908..688454d6b562ec3 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -353,6 +353,10 @@ Bug Fixes to C++ Support
   NTTP types are compared with the '
diff ' method.
   (`#66744 https://github.com/llvm/llvm-project/issues/66744`)
 
+- Fix crash caused by a spaceship operator returning a comparision category by
+  reference. Fixes:
+  (`#64162 <https://github.com/llvm/llvm-project/issues/64162>`_)
+
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^
 - Fixed an import failure of recursive friend class template.

diff  --git a/clang/lib/AST/ExprCXX.cpp b/clang/lib/AST/ExprCXX.cpp
index efb64842fb6d96d..06163255f9b5e54 100644
--- a/clang/lib/AST/ExprCXX.cpp
+++ b/clang/lib/AST/ExprCXX.cpp
@@ -111,7 +111,7 @@ CXXRewrittenBinaryOperator::getDecomposedForm() const {
     return Result;
 
   // Otherwise, we expect a <=> to now be on the LHS.
-  E = Result.LHS->IgnoreImplicitAsWritten();
+  E = Result.LHS->IgnoreUnlessSpelledInSource();
   if (auto *BO = dyn_cast<BinaryOperator>(E)) {
     assert(BO->getOpcode() == BO_Cmp);
     Result.LHS = BO->getLHS();

diff  --git a/clang/test/SemaCXX/compare-cxx2a.cpp b/clang/test/SemaCXX/compare-cxx2a.cpp
index 619e16aa7458179..15a0baccfca17a2 100644
--- a/clang/test/SemaCXX/compare-cxx2a.cpp
+++ b/clang/test/SemaCXX/compare-cxx2a.cpp
@@ -479,3 +479,26 @@ void DoSomething() {
                                                   // expected-note  {{undefined function 'operator++' cannot be used in a constant expression}}
 }
 }
+
+namespace GH64162 {
+struct S {
+    const std::strong_ordering& operator<=>(const S&) const = default;
+};
+bool test(S s) {
+    return s < s; // We expect this not to crash anymore
+}
+
+// Following example never crashed but worth adding in because it is related
+struct A {};
+bool operator<(A, int);
+
+struct B {
+    operator A();
+};
+
+struct C {
+    B operator<=>(C);
+};
+
+bool f(C c) { return c < c; }
+}