[Clang] [Sema] Handle this in __restrict-qualified member functions properly by Sirraide · Pull Request #83187 · llvm/llvm-project (original) (raw)

@llvm/pr-subscribers-clang

Author: None (Sirraide)

Changes

When resolving the type of this inside a member function, we were attaching all qualifiers present on the member function to the class type and then making it a pointer; however, __restrict, unlike const and volatile, needs to be attached to the pointer type rather than the pointee type.

This fixes #82941.

Full diff: https://github.com/llvm/llvm-project/pull/83187.diff

4 Files Affected:

• (modified) clang/docs/ReleaseNotes.rst (+3)
• (modified) clang/lib/AST/DeclCXX.cpp (+13-2)
• (modified) clang/lib/Sema/SemaExprCXX.cpp (+1-1)
• (added) clang/test/SemaCXX/restrict-this.cpp (+51)

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 7e16b9f0c67dbd..d420f572a84487 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -290,6 +290,9 @@ Bug Fixes to C++ Support lookup searches the bases of an incomplete class.

• Fix a crash when an unresolved overload set is encountered on the RHS of a .* operator. (#53815 <https://github.com/llvm/llvm-project/issues/53815>_) +- In __restrict-qualified member functions, attach __restrict to the pointer type of

• this rather than the pointee type.
• Fixes (#82941 <https://github.com/llvm/llvm-project/issues/82941>_).

Bug Fixes to AST Handling ^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/clang/lib/AST/DeclCXX.cpp b/clang/lib/AST/DeclCXX.cpp index 117e802dae2d9d..b4f2327d9c560a 100644 --- a/clang/lib/AST/DeclCXX.cpp +++ b/clang/lib/AST/DeclCXX.cpp @@ -2543,8 +2543,19 @@ QualType CXXMethodDecl::getThisType(const FunctionProtoType *FPT, const CXXRecordDecl *Decl) { ASTContext &C = Decl->getASTContext(); QualType ObjectTy = ::getThisObjectType(C, FPT, Decl);

• return C.getLangOpts().HLSL ? C.getLValueReferenceType(ObjectTy)

•                          : C.getPointerType(ObjectTy);

• // Unlike 'const' and 'volatile', a '__restrict' qualifier must be
• // attached to the pointer type, not the pointee.
• bool Restrict = FPT->getMethodQuals().hasRestrict();
• if (Restrict)
• ObjectTy.removeLocalRestrict();
• ObjectTy = C.getLangOpts().HLSL ? C.getLValueReferenceType(ObjectTy)

•                              : C.getPointerType(ObjectTy);

• if (Restrict)
• ObjectTy.addRestrict();
• return ObjectTy; }

QualType CXXMethodDecl::getThisType() const { diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp index 59758d3bd6d1a3..c4750ce78fa9c1 100644 --- a/clang/lib/Sema/SemaExprCXX.cpp +++ b/clang/lib/Sema/SemaExprCXX.cpp @@ -1220,7 +1220,7 @@ static QualType adjustCVQualifiersForCXXThisWithinLambda( : nullptr; } }

• return ASTCtx.getPointerType(ClassType);

• return ThisTy; }

QualType Sema::getCurrentThisType() { diff --git a/clang/test/SemaCXX/restrict-this.cpp b/clang/test/SemaCXX/restrict-this.cpp new file mode 100644 index 00000000000000..8cd89f0f36a76c --- /dev/null +++ b/clang/test/SemaCXX/restrict-this.cpp @@ -0,0 +1,51 @@ +// RUN: %clang_cc1 -verify -fsyntax-only %s +// expected-no-diagnostics + +struct C {

• void f() __restrict {
• static_assert(__is_same(decltype(this), C *__restrict));
• (void) this {

•  static_assert(__is_same(decltype(this), C *__restrict));

•  (void) [this]() { static_assert(__is_same(decltype(this), C *__restrict)); };

•  // By-value capture means 'this' is now a different object; do not

•  // make it __restrict.

•  (void) [*this]() { static_assert(__is_same(decltype(this), const C *)); };

•  (void) [*this]() mutable { static_assert(__is_same(decltype(this), C *)); };

• };
• } +};
• +template struct TC {
• void f() __restrict {
• static_assert(__is_same(decltype(this), TC *__restrict));
• (void) this {

•  static_assert(__is_same(decltype(this), TC<int> *__restrict));

•  (void) [this]() { static_assert(__is_same(decltype(this), TC<int> *__restrict)); };

•  // By-value capture means 'this' is now a different object; do not

•  // make it __restrict.

•  (void) [*this]() { static_assert(__is_same(decltype(this), const TC<int> *)); };

•  (void) [*this]() mutable { static_assert(__is_same(decltype(this), TC<int> *)); };

• };
• } +};
• +void f() {
• TC{}.f(); +}
• +namespace gh82941 { +void f(int& x) {
• (void)x;

+} + +class C {

• int x;
• void g() __restrict;

+}; + +void C::g() __restrict {

• f(this->x);

+} +}