Revert "[Clang] Fix dependency of SourceLocExpr. (#78436)"

This reverts commit 8c2b0d4.

Author: sys-ce-bb

clang/docs/ReleaseNotes.rst

@@ -972,10 +972,6 @@ Bug Fixes to C++ Support
   (`#57410 <https://github.com/llvm/llvm-project/issues/57410>`_) and
   (`#76604 <https://github.com/llvm/llvm-project/issues/57410>`_)
 
-- Fix a bug where clang would produce inconsistent values when
-  ``std::source_location::current()`` was used in a function template.
-  Fixes (`#78128 <https://github.com/llvm/llvm-project/issues/78128>`_)
-
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^
 - Fixed an import failure of recursive friend class template.

clang/include/clang/AST/Expr.h

@@ -4808,17 +4808,6 @@ class SourceLocExpr final : public Expr {
     return T->getStmtClass() == SourceLocExprClass;
   }
 
-  static bool MayBeDependent(SourceLocIdentKind Kind) {
-    switch (Kind) {
-    case SourceLocIdentKind::Function:
-    case SourceLocIdentKind::FuncSig:
-    case SourceLocIdentKind::SourceLocStruct:
-      return true;
-    default:
-      return false;
-    }
-  }
-
 private:
   friend class ASTStmtReader;
 };

clang/lib/AST/Expr.cpp

@@ -2274,10 +2274,7 @@ SourceLocExpr::SourceLocExpr(const ASTContext &Ctx, SourceLocIdentKind Kind,
     : Expr(SourceLocExprClass, ResultTy, VK_PRValue, OK_Ordinary),
       BuiltinLoc(BLoc), RParenLoc(RParenLoc), ParentContext(ParentContext) {
   SourceLocExprBits.Kind = llvm::to_underlying(Kind);
-  // In dependent contexts, function names may change.
-  setDependence(MayBeDependent(Kind) && ParentContext->isDependentContext()
-                    ? ExprDependence::Value
-                    : ExprDependence::None);
+  setDependence(ExprDependence::None);
 }
 
 StringRef SourceLocExpr::getBuiltinStr() const {

clang/lib/Sema/TreeTransform.h

@@ -12200,7 +12200,7 @@ TreeTransform<Derived>::TransformCXXMemberCallExpr(CXXMemberCallExpr *E) {
 
 template <typename Derived>
 ExprResult TreeTransform<Derived>::TransformSourceLocExpr(SourceLocExpr *E) {
-  bool NeedRebuildFunc = SourceLocExpr::MayBeDependent(E->getIdentKind()) &&
+  bool NeedRebuildFunc = E->getIdentKind() == SourceLocIdentKind::Function &&
                          getSema().CurContext != E->getParentContext();
 
   if (!getDerived().AlwaysRebuild() && !NeedRebuildFunc)

clang/test/SemaCXX/source_location.cpp

@@ -805,30 +805,3 @@ static_assert(S(0).j == S{0}.j);
 static_assert(S(0).j == S{0}.i);
 }
 #endif
-
-namespace GH78128 {
-
-template<int N>
-constexpr int f() {
-  return N;
-}
-
-template<typename T>
-void foo() {
-  constexpr auto* F1 = std::source_location::current().function();
-  static_assert(__builtin_strlen(F1) == f<__builtin_strlen(F1)>());
-
-  constexpr auto* F2 = __builtin_FUNCTION();
-  static_assert(__builtin_strlen(F2) == f<__builtin_strlen(F2)>());
-
-#ifdef MS
-  constexpr auto* F3 = __builtin_FUNCSIG();
-  static_assert(__builtin_strlen(F3) == f<__builtin_strlen(F3)>());
-#endif
-}
-
-void test() {
-  foo<int>();
-}
-
-}