From 926717e50953413e0156e77c483cf748ee8ab814 Mon Sep 17 00:00:00 2001
From: zebullon <zebulax@gmail.com>
Date: Sun, 5 Jan 2025 11:09:55 +0900
Subject: [PATCH] Add flag

---
 clang/include/clang/Basic/DiagnosticFrontendKinds.td |  3 +++
 clang/include/clang/Basic/Features.def               |  1 +
 clang/include/clang/Basic/LangOptions.def            |  1 +
 clang/include/clang/Driver/Options.td                |  5 +++++
 clang/lib/Frontend/CompilerInvocation.cpp            |  8 ++++++--
 clang/lib/Parse/ParseDeclCXX.cpp                     | 11 +++++++++--
 6 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/clang/include/clang/Basic/DiagnosticFrontendKinds.td b/clang/include/clang/Basic/DiagnosticFrontendKinds.td
index 68d0e844780b4..9a8faa3e38aa0 100644
--- a/clang/include/clang/Basic/DiagnosticFrontendKinds.td
+++ b/clang/include/clang/Basic/DiagnosticFrontendKinds.td
@@ -105,6 +105,9 @@ def err_fe_reflection_incompatible_with_blocks : Error<
 def err_fe_parameter_reflection_without_reflection : Error<
     "cannot specify '-fparameter-reflection' without '-freflection'">,
     DefaultFatal;
+def err_fe_attribute_reflection_without_reflection : Error<
+    "cannot specify '-fattribute-reflection' without '-freflection'">,
+    DefaultFatal;
 def err_fe_dependency_file_requires_MT : Error<
     "-dependency-file requires at least one -MT or -MQ option">;
 def err_fe_invalid_plugin_name : Error<
diff --git a/clang/include/clang/Basic/Features.def b/clang/include/clang/Basic/Features.def
index 4f826ac0b1cc0..f0941542cbfbe 100644
--- a/clang/include/clang/Basic/Features.def
+++ b/clang/include/clang/Basic/Features.def
@@ -310,6 +310,7 @@ FEATURE(cxx_abi_relative_vtable, LangOpts.CPlusPlus && LangOpts.RelativeCXXABIVT
 FEATURE(reflection, LangOpts.Reflection)
 FEATURE(reflection_new_syntax, LangOpts.ReflectionNewSyntax)
 FEATURE(parameter_reflection, LangOpts.ParameterReflection)
+FEATURE(attribute_reflection, LangOpts.AttributeReflection)
 FEATURE(expansion_statements, LangOpts.ExpansionStatements)
 FEATURE(annotation_attributes, LangOpts.AnnotationAttributes)
 FEATURE(consteval_blocks, LangOpts.ConstevalBlocks)
diff --git a/clang/include/clang/Basic/LangOptions.def b/clang/include/clang/Basic/LangOptions.def
index b30ecdf17175c..e0ed057032c07 100644
--- a/clang/include/clang/Basic/LangOptions.def
+++ b/clang/include/clang/Basic/LangOptions.def
@@ -314,6 +314,7 @@ LANGOPT(OpenACC           , 1, 0, "OpenACC Enabled")
 LANGOPT(Reflection          , 1, 0, "Experimental C++26 Reflection")
 LANGOPT(ReflectionNewSyntax , 1, 0, "New syntax for C++26 Reflection")
 LANGOPT(ParameterReflection , 1, 0, "Augments C++26 Reflection with function parameter reflection")
+LANGOPT(AttributeReflection , 1, 0, "Augments C++26 Reflection with standard attribute reflection")
 LANGOPT(ExpansionStatements , 1, 0, "Experimental C++26 Expansion Statements")
 LANGOPT(AnnotationAttributes, 1, 0, "Experimental C++26 support for annotations")
 LANGOPT(ConstevalBlocks,      1, 0, "Experimental C++26 support for consteval blocks")
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 255d2ef84a55a..67a6f1056d30b 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -3504,6 +3504,11 @@ defm parameter_reflection : BoolFOption<"parameter-reflection",
   PosFlag<SetTrue, [], [ClangOption, CC1Option],
           "Enable proposed parameter reflection as described by P3096">,
   NegFlag<SetFalse>>;
+defm attribute_reflection : BoolFOption<"attribute-reflection",
+  LangOpts<"AttributeReflection">, DefaultFalse,
+  PosFlag<SetTrue, [], [ClangOption, CC1Option],
+          "Enable proposed parameter reflection as described by P3385">,
+  NegFlag<SetFalse>>;
 defm expansion_statements : BoolFOption<"expansion-statements",
   LangOpts<"ExpansionStatements">, DefaultFalse,
   PosFlag<SetTrue, [], [ClangOption, CC1Option],
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 7e9119f27857b..c40a7d4cb122f 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -615,8 +615,12 @@ static bool FixupInvocation(CompilerInvocation &Invocation,
   if (LangOpts.Reflection) {
     if (LangOpts.Blocks && !LangOpts.ReflectionNewSyntax)
       Diags.Report(diag::err_fe_reflection_incompatible_with_blocks);
-  } else if (LangOpts.ParameterReflection) {
-    Diags.Report(diag::err_fe_parameter_reflection_without_reflection);
+  } else {
+    if (LangOpts.ParameterReflection) {
+      Diags.Report(diag::err_fe_parameter_reflection_without_reflection);
+    } else if (LangOpts.AttributeReflection) {
+      Diags.Report(diag::err_fe_attribute_reflection_without_reflection);
+    }
   }
 
   // The -f[no-]raw-string-literals option is only valid in C and in C++
diff --git a/clang/lib/Parse/ParseDeclCXX.cpp b/clang/lib/Parse/ParseDeclCXX.cpp
index 96bba3244a03d..461f94a9477be 100644
--- a/clang/lib/Parse/ParseDeclCXX.cpp
+++ b/clang/lib/Parse/ParseDeclCXX.cpp
@@ -5088,11 +5088,18 @@ bool Parser::tryParseSpliceAttrSpecifier(ParsedAttributes &Attrs,
   if (!Tok.is(tok::l_splice)) {
     return true;
   }
+  if(!getLangOpts().AttributeReflection) {
+    Diag(Tok.getLocation(), diag::p3385_err_attribute_splicing_error)
+        << "attribute splicing is gated behind -fattribute-reflection";
+    SkipUntil(tok::r_splice);
+    ExpectAndConsume(tok::r_splice);
+  }
+
   if (ParseCXXSpliceSpecifier()) {
     // FIXME diagnostic is terrible...
     Diag(Tok.getLocation(), diag::p3385_err_attribute_splicing_error)
         << "invalid expression in attribute splicing";
-    return true; // yea...Dont know what kind of convention that is
+    return true;
   }
   if (!Tok.is(tok::annot_splice)) {
     return true;
@@ -5106,7 +5113,7 @@ bool Parser::tryParseSpliceAttrSpecifier(ParsedAttributes &Attrs,
   ExprResult Result = getExprAnnotation(Tok);
   ConsumeAnnotationToken();
 
-  // TODO export to ActOnBlablabla() is the `iDiOmAtIc WaY`
+  // TODO offload to ActOnBlablabla() is the `iDiOmAtIc WaY`
   //
   auto *SpliceExpr = cast<CXXSpliceSpecifierExpr>(Result.get());
   Expr::EvalResult ER;