Add support of Windows Trace Logging macros

Consider the following code:

    #include <windows.h>
    #include <TraceLoggingActivity.h>
    #include <TraceLoggingProvider.h>
    #include <winmeta.h>

    TRACELOGGING_DEFINE_PROVIDER(
        g_hMyComponentProvider,
        "SimpleTraceLoggingProvider",
        // {0205c616-cf97-5c11-9756-56a2cee02ca7}
        (0x0205c616,0xcf97,0x5c11,0x97,0x56,0x56,0xa2,0xce,0xe0,0x2c,0xa7));

    void test()
    {
        TraceLoggingFunction(g_hMyComponentProvider);
    }

    int main()
    {
        TraceLoggingRegister(g_hMyComponentProvider);
        test();
        TraceLoggingUnregister(g_hMyComponentProvider);
    }

It compiles with MSVC, but clang-cl reports an error:

    C:\Program Files (x86)\Windows Kits\10\\include\10.0.22621.0\\shared/TraceLoggingActivity.h(377,30): note: expanded from macro '_tlgThisFunctionName'
    #define _tlgThisFunctionName __FUNCTION__
                                 ^
    .\tl.cpp(14,5): error: cannot initialize an array element of type 'char' with an lvalue of type 'const char[5]'
        TraceLoggingFunction(g_hMyComponentProvider);
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The second commit is not needed to support above code, however, during isolated tests in ms_predefined_expr.cpp
I found that MSVC accepts code with constexpr, whereas clang-cl does not.
I see that in most places PredefinedExpr is supported in constant evaluation, so I didn't wrap my code with ``if(MicrosoftExt)``.

Reviewed By: cor3ntin

Differential Revision: https://reviews.llvm.org/D158591

clang/docs/ReleaseNotes.rst

@@ -211,6 +211,8 @@ Bug Fixes in This Version
 - Clang now reports ``-Wformat`` for bool value and char specifier confusion
   in scanf. Fixes
   (`#64987 <https://github.com/llvm/llvm-project/issues/64987>`_)
+- Support MSVC predefined macro expressions in constant expressions and in
+  local structs.
 
 Bug Fixes to Compiler Builtins
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

clang/include/clang/Sema/Sema.h

@@ -3620,10 +3620,6 @@ public:
   /// in a 'block', this returns the containing context.
   NamedDecl *getCurFunctionOrMethodDecl() const;
 
-  /// getCurLocalScopeDecl - Return the Decl for either of:
-  /// block, lambda, captured statement, function, or nullptr.
-  Decl *getCurLocalScopeDecl();
-
   /// Add this decl to the scope shadowed decl chains.
   void PushOnScopeChains(NamedDecl *D, Scope *S, bool AddToContext = true);
 

clang/lib/AST/ExprConstant.cpp

@@ -7528,6 +7528,9 @@ public:
     return Error(E);
   }
 
+  bool VisitPredefinedExpr(const PredefinedExpr *E) {
+    return StmtVisitorTy::Visit(E->getFunctionName());
+  }
   bool VisitConstantExpr(const ConstantExpr *E) {
     if (E->hasAPValueResult())
       return DerivedSuccess(E->getAPValueResult(), E);

clang/lib/Sema/Sema.cpp

@@ -1491,18 +1491,6 @@ NamedDecl *Sema::getCurFunctionOrMethodDecl() const {
   return nullptr;
 }
 
-Decl *Sema::getCurLocalScopeDecl() {
-  if (const BlockScopeInfo *BSI = getCurBlock())
-    return BSI->TheDecl;
-  if (const LambdaScopeInfo *LSI = getCurLambda())
-    return LSI->CallOperator;
-  if (const CapturedRegionScopeInfo *CSI = getCurCapturedRegion())
-    return CSI->TheCapturedDecl;
-  if (NamedDecl *ND = getCurFunctionOrMethodDecl())
-    return ND;
-  return nullptr;
-}
-
 LangAS Sema::getDefaultCXXMethodAddrSpace() const {
   if (getLangOpts().OpenCL)
     return getASTContext().getDefaultOpenCLPointeeAddrSpace();

clang/lib/Sema/SemaExpr.cpp

@@ -1904,6 +1904,15 @@ static PredefinedExpr::IdentKind getPredefinedExprKind(tok::TokenKind Kind) {
   }
 }
 
+/// getPredefinedExprDecl - Returns Decl of a given DeclContext that can be used
+/// to determine the value of a PredefinedExpr. This can be either a
+/// block, lambda, captured statement, function, otherwise a nullptr.
+static Decl *getPredefinedExprDecl(DeclContext *DC) {
+  while (DC && !isa<BlockDecl, CapturedDecl, FunctionDecl, ObjCMethodDecl>(DC))
+    DC = DC->getParent();
+  return cast_or_null<Decl>(DC);
+}
+
 /// getUDSuffixLoc - Create a SourceLocation for a ud-suffix, given the
 /// location of the token and the offset of the ud-suffix within it.
 static SourceLocation getUDSuffixLoc(Sema &S, SourceLocation TokLoc,
@@ -1984,7 +1993,7 @@ Sema::ExpandFunctionLocalPredefinedMacros(ArrayRef<Token> Toks) {
   // Note: Although function local macros are defined only inside functions,
   // we ensure a valid `CurrentDecl` even outside of a function. This allows
   // expansion of macros into empty string literals without additional checks.
-  Decl *CurrentDecl = getCurLocalScopeDecl();
+  Decl *CurrentDecl = getPredefinedExprDecl(CurContext);
   if (!CurrentDecl)
     CurrentDecl = Context.getTranslationUnitDecl();
 
@@ -3705,7 +3714,7 @@ static void ConvertUTF8ToWideString(unsigned CharByteWidth, StringRef Source,
 
 ExprResult Sema::BuildPredefinedExpr(SourceLocation Loc,
                                      PredefinedExpr::IdentKind IK) {
-  Decl *currentDecl = getCurLocalScopeDecl();
+  Decl *currentDecl = getPredefinedExprDecl(CurContext);
   if (!currentDecl) {
     Diag(Loc, diag::ext_predef_outside_function);
     currentDecl = Context.getTranslationUnitDecl();

clang/test/Sema/ms_predefined_expr.cpp

@@ -168,3 +168,40 @@ void test_static_assert() {
 void test_char_injection(decltype(sizeof('"')), decltype(sizeof("()"))) {
   unused("" __FUNCSIG__); // expected-warning{{expansion of predefined identifier '__FUNCSIG__' to a string literal is a Microsoft extension}}
 }
+
+void test_in_struct_init() {
+  struct {
+    char F[sizeof(__FUNCTION__)];
+  } s1 = { __FUNCTION__ }; // expected-warning{{initializing an array from a '__FUNCTION__' predefined identifier is a Microsoft extension}}
+
+  struct {
+    char F[sizeof("F:" __FUNCTION__)]; // expected-warning{{expansion of predefined identifier '__FUNCTION__' to a string literal is a Microsoft extension}}
+  } s2 = { "F:" __FUNCTION__ }; // expected-warning{{expansion of predefined identifier '__FUNCTION__' to a string literal is a Microsoft extension}}
+
+  class C {
+    public:
+      struct {
+        char F[sizeof(__FUNCTION__)];
+      } s;
+  } c1 = { { __FUNCTION__ } }; // expected-warning{{initializing an array from a '__FUNCTION__' predefined identifier is a Microsoft extension}}
+}
+
+void test_in_constexpr_struct_init() {
+  struct {
+    char F[sizeof(__FUNCTION__)];
+  } constexpr s1 = { __FUNCTION__ }; // expected-warning{{initializing an array from a '__FUNCTION__' predefined identifier is a Microsoft extension}}
+  ASSERT_EQ(__FUNCTION__, s1.F);
+
+  struct {
+    char F[sizeof("F:" __FUNCTION__)]; // expected-warning{{expansion of predefined identifier '__FUNCTION__' to a string literal is a Microsoft extension}}
+  } constexpr s2 = { "F:" __FUNCTION__ }; // expected-warning{{expansion of predefined identifier '__FUNCTION__' to a string literal is a Microsoft extension}}
+  ASSERT_EQ("F:" __FUNCTION__, s2.F); // expected-warning{{expansion of predefined identifier '__FUNCTION__' to a string literal is a Microsoft extension}}
+
+  class C {
+    public:
+      struct {
+        char F[sizeof("F:" __FUNCTION__)]; // expected-warning{{expansion of predefined identifier '__FUNCTION__' to a string literal is a Microsoft extension}}
+      } s;
+  } constexpr c1 = { { "F:" __FUNCTION__ } }; // expected-warning{{expansion of predefined identifier '__FUNCTION__' to a string literal is a Microsoft extension}}
+  ASSERT_EQ("F:" __FUNCTION__, c1.s.F); // expected-warning{{expansion of predefined identifier '__FUNCTION__' to a string literal is a Microsoft extension}}
+}