From 80f470ce8859ddff5114a0cc9c0280663ada0fbc Mon Sep 17 00:00:00 2001
From: sys_ce_bb <sys_ce_bb@intel.com>
Date: Sun, 21 Jan 2024 06:30:34 -0800
Subject: [PATCH] Revert "[Clang] Fix dependency of SourceLocExpr. (#78436)"

This reverts commit 8c2b0d4175dcfe669a43d0173fd00ed3c16dbdaa.
---
 clang/docs/ReleaseNotes.rst            |  4 ----
 clang/include/clang/AST/Expr.h         | 11 -----------
 clang/lib/AST/Expr.cpp                 |  5 +----
 clang/lib/Sema/TreeTransform.h         |  2 +-
 clang/test/SemaCXX/source_location.cpp | 27 --------------------------
 5 files changed, 2 insertions(+), 47 deletions(-)

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 0ea6f93a1f5df..cf52c1e66b91b 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/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.
diff --git a/clang/include/clang/AST/Expr.h b/clang/include/clang/AST/Expr.h
index ff674f07275e8..2cca5b35478ce 100644
--- a/clang/include/clang/AST/Expr.h
+++ b/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;
 };
diff --git a/clang/lib/AST/Expr.cpp b/clang/lib/AST/Expr.cpp
index e6919e03fd246..0458c8a4f6c2e 100644
--- a/clang/lib/AST/Expr.cpp
+++ b/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 {
diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
index 36b68b2272273..30431fa350f46 100644
--- a/clang/lib/Sema/TreeTransform.h
+++ b/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)
diff --git a/clang/test/SemaCXX/source_location.cpp b/clang/test/SemaCXX/source_location.cpp
index 7414fbce7828d..e92fb35b653a8 100644
--- a/clang/test/SemaCXX/source_location.cpp
+++ b/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>();
-}
-
-}