Add 'enum_select' diagnostic selection to clang. (#122505)

erichkeane · AaronBallman · web-flow · commit bf17016a92bc · 2025-01-15T12:59:08.000-08:00
This causes us to generate an enum to go along with the select
diagnostic, which allows for clearer diagnostic error emit lines.

The syntax for this is:

%enum_select&lt;EnumerationName&gt;{%OptionalEnumeratorName{Text}|{Text2}}0

Where the curley brackets around the select-text are only required if an
Enumerator name is provided.

The TableGen here emits this as a normal 'select' to the frontend, which
permits us to reuse all of the existing 'select' infrastructure.
Documentation is the same as well.

---------

Co-authored-by: Aaron Ballman &lt;aaron@aaronballman.com&gt;
diff --git a/clang/docs/InternalsManual.rst b/clang/docs/InternalsManual.rst
@@ -276,6 +276,21 @@ Description:
   diagnostic instead of having to do things textually.  The selected string
   does undergo formatting.
 
+**"enum_select format**
+
+Example:
+  ``unknown frobbling of a %enum_select<FrobbleKind>{%VarDecl{variable declaration}|%FuncDecl{function declaration}}0 when blarging``
+Class:
+  Integers
+Description:
+  This format specifier is used exactly like a ``select`` specifier, except it
+  additionally generates a namespace, enumeration, and enumerator list based on
+  the format string given. In the above case, a namespace is generated named
+  ``FrobbleKind`` that has an unscoped enumeration with the enumerators
+  ``VarDecl`` and ``FuncDecl`` which correspond to the values 0 and 1. This
+  permits a clearer use of the ``Diag`` in source code, as the above could be
+  called as: ``Diag(Loc, diag::frobble) << diag::FrobbleKind::VarDecl``.
+
 **"plural" format**
 
 Example:
diff --git a/clang/include/clang/Basic/CMakeLists.txt b/clang/include/clang/Basic/CMakeLists.txt
@@ -3,6 +3,11 @@ macro(clang_diag_gen component)
     -gen-clang-diags-defs -clang-component=${component}
     SOURCE Diagnostic.td
     TARGET ClangDiagnostic${component})
+
+  clang_tablegen(Diagnostic${component}Enums.inc
+    -gen-clang-diags-enums -clang-component=${component}
+    SOURCE Diagnostic.td
+    TARGET ClangDiagnostic${component}Enums)
 endmacro(clang_diag_gen)
 
 clang_diag_gen(Analysis)
diff --git a/clang/include/clang/Basic/DiagnosticAST.h b/clang/include/clang/Basic/DiagnosticAST.h
@@ -22,6 +22,19 @@ enum {
 #undef DIAG
   NUM_BUILTIN_AST_DIAGNOSTICS
 };
+
+#define DIAG_ENUM(ENUM_NAME)                                                   \
+  namespace ENUM_NAME {                                                        \
+  enum {
+#define DIAG_ENUM_ITEM(IDX, NAME) NAME = IDX,
+#define DIAG_ENUM_END()                                                        \
+  }                                                                            \
+  ;                                                                            \
+  }
+#include "clang/Basic/DiagnosticASTEnums.inc"
+#undef DIAG_ENUM_END
+#undef DIAG_ENUM_ITEM
+#undef DIAG_ENUM
 } // end namespace diag
 } // end namespace clang
 
diff --git a/clang/include/clang/Basic/DiagnosticAnalysis.h b/clang/include/clang/Basic/DiagnosticAnalysis.h
@@ -22,6 +22,18 @@ enum {
 #undef DIAG
   NUM_BUILTIN_ANALYSIS_DIAGNOSTICS
 };
+#define DIAG_ENUM(ENUM_NAME)                                                   \
+  namespace ENUM_NAME {                                                        \
+  enum {
+#define DIAG_ENUM_ITEM(IDX, NAME) NAME = IDX,
+#define DIAG_ENUM_END()                                                        \
+  }                                                                            \
+  ;                                                                            \
+  }
+#include "clang/Basic/DiagnosticAnalysisEnums.inc"
+#undef DIAG_ENUM_END
+#undef DIAG_ENUM_ITEM
+#undef DIAG_ENUM
 } // end namespace diag
 } // end namespace clang
 
diff --git a/clang/include/clang/Basic/DiagnosticComment.h b/clang/include/clang/Basic/DiagnosticComment.h
@@ -22,6 +22,19 @@ enum {
 #undef DIAG
   NUM_BUILTIN_COMMENT_DIAGNOSTICS
 };
+
+#define DIAG_ENUM(ENUM_NAME)                                                   \
+  namespace ENUM_NAME {                                                        \
+  enum {
+#define DIAG_ENUM_ITEM(IDX, NAME) NAME = IDX,
+#define DIAG_ENUM_END()                                                        \
+  }                                                                            \
+  ;                                                                            \
+  }
+#include "clang/Basic/DiagnosticCommentEnums.inc"
+#undef DIAG_ENUM_END
+#undef DIAG_ENUM_ITEM
+#undef DIAG_ENUM
 } // end namespace diag
 } // end namespace clang
 
diff --git a/clang/include/clang/Basic/DiagnosticCrossTU.h b/clang/include/clang/Basic/DiagnosticCrossTU.h
@@ -22,6 +22,19 @@ enum {
 #undef DIAG
   NUM_BUILTIN_CROSSTU_DIAGNOSTICS
 };
+
+#define DIAG_ENUM(ENUM_NAME)                                                   \
+  namespace ENUM_NAME {                                                        \
+  enum {
+#define DIAG_ENUM_ITEM(IDX, NAME) NAME = IDX,
+#define DIAG_ENUM_END()                                                        \
+  }                                                                            \
+  ;                                                                            \
+  }
+#include "clang/Basic/DiagnosticCrossTUEnums.inc"
+#undef DIAG_ENUM_END
+#undef DIAG_ENUM_ITEM
+#undef DIAG_ENUM
 } // end namespace diag
 } // end namespace clang
 
diff --git a/clang/include/clang/Basic/DiagnosticDriver.h b/clang/include/clang/Basic/DiagnosticDriver.h
@@ -22,6 +22,19 @@ enum {
 #undef DIAG
   NUM_BUILTIN_DRIVER_DIAGNOSTICS
 };
+
+#define DIAG_ENUM(ENUM_NAME)                                                   \
+  namespace ENUM_NAME {                                                        \
+  enum {
+#define DIAG_ENUM_ITEM(IDX, NAME) NAME = IDX,
+#define DIAG_ENUM_END()                                                        \
+  }                                                                            \
+  ;                                                                            \
+  }
+#include "clang/Basic/DiagnosticDriverEnums.inc"
+#undef DIAG_ENUM_END
+#undef DIAG_ENUM_ITEM
+#undef DIAG_ENUM
 } // end namespace diag
 } // end namespace clang
 
diff --git a/clang/include/clang/Basic/DiagnosticFrontend.h b/clang/include/clang/Basic/DiagnosticFrontend.h
@@ -22,6 +22,19 @@ enum {
 #undef DIAG
   NUM_BUILTIN_FRONTEND_DIAGNOSTICS
 };
+
+#define DIAG_ENUM(ENUM_NAME)                                                   \
+  namespace ENUM_NAME {                                                        \
+  enum {
+#define DIAG_ENUM_ITEM(IDX, NAME) NAME = IDX,
+#define DIAG_ENUM_END()                                                        \
+  }                                                                            \
+  ;                                                                            \
+  }
+#include "clang/Basic/DiagnosticFrontendEnums.inc"
+#undef DIAG_ENUM_END
+#undef DIAG_ENUM_ITEM
+#undef DIAG_ENUM
 } // end namespace diag
 } // end namespace clang
 
diff --git a/clang/include/clang/Basic/DiagnosticInstallAPI.h b/clang/include/clang/Basic/DiagnosticInstallAPI.h
@@ -21,6 +21,19 @@ enum {
 #undef DIAG
   NUM_BUILTIN_INSTALLAPI_DIAGNOSTICS
 };
+
+#define DIAG_ENUM(ENUM_NAME)                                                   \
+  namespace ENUM_NAME {                                                        \
+  enum {
+#define DIAG_ENUM_ITEM(IDX, NAME) NAME = IDX,
+#define DIAG_ENUM_END()                                                        \
+  }                                                                            \
+  ;                                                                            \
+  }
+#include "clang/Basic/DiagnosticInstallAPIEnums.inc"
+#undef DIAG_ENUM_END
+#undef DIAG_ENUM_ITEM
+#undef DIAG_ENUM
 } // namespace diag
 } // namespace clang
 #endif // LLVM_CLANG_BASIC_DIAGNOSTICINSTALLAPI_H
diff --git a/clang/include/clang/Basic/DiagnosticLex.h b/clang/include/clang/Basic/DiagnosticLex.h
@@ -22,6 +22,18 @@ enum {
 #undef DIAG
   NUM_BUILTIN_LEX_DIAGNOSTICS
 };
+#define DIAG_ENUM(ENUM_NAME)                                                   \
+  namespace ENUM_NAME {                                                        \
+  enum {
+#define DIAG_ENUM_ITEM(IDX, NAME) NAME = IDX,
+#define DIAG_ENUM_END()                                                        \
+  }                                                                            \
+  ;                                                                            \
+  }
+#include "clang/Basic/DiagnosticLexEnums.inc"
+#undef DIAG_ENUM_END
+#undef DIAG_ENUM_ITEM
+#undef DIAG_ENUM
 } // end namespace diag
 } // end namespace clang
 
diff --git a/clang/include/clang/Basic/DiagnosticParse.h b/clang/include/clang/Basic/DiagnosticParse.h
@@ -22,6 +22,19 @@ enum {
 #undef DIAG
   NUM_BUILTIN_PARSE_DIAGNOSTICS
 };
+
+#define DIAG_ENUM(ENUM_NAME)                                                   \
+  namespace ENUM_NAME {                                                        \
+  enum {
+#define DIAG_ENUM_ITEM(IDX, NAME) NAME = IDX,
+#define DIAG_ENUM_END()                                                        \
+  }                                                                            \
+  ;                                                                            \
+  }
+#include "clang/Basic/DiagnosticParseEnums.inc"
+#undef DIAG_ENUM_END
+#undef DIAG_ENUM_ITEM
+#undef DIAG_ENUM
 } // end namespace diag
 } // end namespace clang
 
diff --git a/clang/include/clang/Basic/DiagnosticRefactoring.h b/clang/include/clang/Basic/DiagnosticRefactoring.h
@@ -22,6 +22,19 @@ enum {
 #undef DIAG
   NUM_BUILTIN_REFACTORING_DIAGNOSTICS
 };
+
+#define DIAG_ENUM(ENUM_NAME)                                                   \
+  namespace ENUM_NAME {                                                        \
+  enum {
+#define DIAG_ENUM_ITEM(IDX, NAME) NAME = IDX,
+#define DIAG_ENUM_END()                                                        \
+  }                                                                            \
+  ;                                                                            \
+  }
+#include "clang/Basic/DiagnosticRefactoringEnums.inc"
+#undef DIAG_ENUM_END
+#undef DIAG_ENUM_ITEM
+#undef DIAG_ENUM
 } // end namespace diag
 } // end namespace clang
 
diff --git a/clang/include/clang/Basic/DiagnosticSema.h b/clang/include/clang/Basic/DiagnosticSema.h
@@ -22,6 +22,19 @@ enum {
 #undef DIAG
   NUM_BUILTIN_SEMA_DIAGNOSTICS
 };
+
+#define DIAG_ENUM(ENUM_NAME)                                                   \
+  namespace ENUM_NAME {                                                        \
+  enum {
+#define DIAG_ENUM_ITEM(IDX, NAME) NAME = IDX,
+#define DIAG_ENUM_END()                                                        \
+  }                                                                            \
+  ;                                                                            \
+  }
+#include "clang/Basic/DiagnosticSemaEnums.inc"
+#undef DIAG_ENUM_END
+#undef DIAG_ENUM_ITEM
+#undef DIAG_ENUM
 } // end namespace diag
 } // end namespace clang
 
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -617,9 +617,11 @@ def err_ambiguous_inherited_constructor : Error<
   "constructor of %0 inherited from multiple base class subobjects">;
 def note_ambiguous_inherited_constructor_using : Note<
   "inherited from base class %0 here">;
-def note_using_decl_class_member_workaround : Note<
-  "use %select{an alias declaration|a typedef declaration|a reference|"
-  "a const variable|a constexpr variable}0 instead">;
+def note_using_decl_class_member_workaround
+    : Note<"use %enum_select<MemClassWorkaround>{%AliasDecl{an alias "
+           "declaration}|%TypedefDecl{a typedef declaration}|%ReferenceDecl{a "
+           "reference}|%ConstVar{a const variable}|%ConstexprVar{a constexpr "
+           "variable}}0 instead">;
 def err_using_decl_can_not_refer_to_namespace : Error<
   "using declaration cannot refer to a namespace">;
 def note_namespace_using_decl : Note<
diff --git a/clang/include/clang/Basic/DiagnosticSerialization.h b/clang/include/clang/Basic/DiagnosticSerialization.h
@@ -22,6 +22,19 @@ enum {
 #undef DIAG
   NUM_BUILTIN_SERIALIZATION_DIAGNOSTICS
 };
+
+#define DIAG_ENUM(ENUM_NAME)                                                   \
+  namespace ENUM_NAME {                                                        \
+  enum {
+#define DIAG_ENUM_ITEM(IDX, NAME) NAME = IDX,
+#define DIAG_ENUM_END()                                                        \
+  }                                                                            \
+  ;                                                                            \
+  }
+#include "clang/Basic/DiagnosticSerializationEnums.inc"
+#undef DIAG_ENUM_END
+#undef DIAG_ENUM_ITEM
+#undef DIAG_ENUM
 } // end namespace diag
 } // end namespace clang
 
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -13217,18 +13217,18 @@ bool Sema::CheckUsingDeclQualifier(SourceLocation UsingLoc, bool HasTypename,
         if (getLangOpts().CPlusPlus11) {
           // Convert 'using X::Y;' to 'using Y = X::Y;'.
           Diag(SS.getBeginLoc(), diag::note_using_decl_class_member_workaround)
-            << 0 // alias declaration
-            << FixItHint::CreateInsertion(SS.getBeginLoc(),
-                                          NameInfo.getName().getAsString() +
-                                              " = ");
+              << diag::MemClassWorkaround::AliasDecl
+              << FixItHint::CreateInsertion(SS.getBeginLoc(),
+                                            NameInfo.getName().getAsString() +
+                                                " = ");
         } else {
           // Convert 'using X::Y;' to 'typedef X::Y Y;'.
           SourceLocation InsertLoc = getLocForEndOfToken(NameInfo.getEndLoc());
           Diag(InsertLoc, diag::note_using_decl_class_member_workaround)
-            << 1 // typedef declaration
-            << FixItHint::CreateReplacement(UsingLoc, "typedef")
-            << FixItHint::CreateInsertion(
-                   InsertLoc, " " + NameInfo.getName().getAsString());
+              << diag::MemClassWorkaround::TypedefDecl
+              << FixItHint::CreateReplacement(UsingLoc, "typedef")
+              << FixItHint::CreateInsertion(
+                     InsertLoc, " " + NameInfo.getName().getAsString());
         }
       } else if (R->getAsSingle<VarDecl>()) {
         // Don't provide a fixit outside C++11 mode; we don't want to suggest
@@ -13241,8 +13241,7 @@ bool Sema::CheckUsingDeclQualifier(SourceLocation UsingLoc, bool HasTypename,
         }
 
         Diag(UsingLoc, diag::note_using_decl_class_member_workaround)
-          << 2 // reference declaration
-          << FixIt;
+            << diag::MemClassWorkaround::ReferenceDecl << FixIt;
       } else if (R->getAsSingle<EnumConstantDecl>()) {
         // Don't provide a fixit outside C++11 mode; we don't want to suggest
         // repeating the type of the enumeration here, and we can't do so if
@@ -13256,8 +13255,10 @@ bool Sema::CheckUsingDeclQualifier(SourceLocation UsingLoc, bool HasTypename,
         }
 
         Diag(UsingLoc, diag::note_using_decl_class_member_workaround)
-          << (getLangOpts().CPlusPlus11 ? 4 : 3) // const[expr] variable
-          << FixIt;
+            << (getLangOpts().CPlusPlus11
+                    ? diag::MemClassWorkaround::ConstexprVar
+                    : diag::MemClassWorkaround::ConstVar)
+            << FixIt;
       }
     }
 
diff --git a/clang/test/TableGen/select-enum-errors.td b/clang/test/TableGen/select-enum-errors.td
@@ -0,0 +1,45 @@
+// RUN: not clang-tblgen --gen-clang-diags-enums -DERROR1 -I%S %s 2>&1 | FileCheck %s --check-prefixes=CHECK,C1
+// RUN: not clang-tblgen --gen-clang-diags-enums -DERROR2 -I%S %s 2>&1 | FileCheck %s --check-prefixes=CHECK,C2
+// RUN: not clang-tblgen --gen-clang-diags-enums -DERROR3 -I%S %s 2>&1 | FileCheck %s --check-prefixes=CHECK,C3
+// RUN: not clang-tblgen --gen-clang-diags-enums -DERROR4 -I%S %s 2>&1 | FileCheck %s --check-prefixes=CHECK,C4
+include "DiagnosticBase.inc"
+
+// No real reason to diagnose these, the namespace generated as the
+// 'enumeration' name will never conflict with the enumerator.
+def EnumerationEnumeratorDupe : Error<"%enum_select<Matchy>{%Matchy{haha}}0">;
+
+// Enumerator values aren't required, though this does seem kind of silly/not
+// particularly useful?
+def NoEnumerators : Error<"%enum_select<Name>{foo|bar|baz}0">;
+
+def DupeNames1 : Error<"%enum_select<DupeName>{}0">;
+def DupeNames2 : Error<"%enum_select<DupeName>{}0">;
+// CHECK: error: Duplicate enumeration name 'DupeName'
+// CHECK-NEXT: def DupeNames2
+// CHECK: note: Previous diagnostic is here
+// CHECK-NEXT: def DupeNames1
+
+def DupeValue : Error<"%enum_select<DupeValue>{%DName{V1}|%DName{V2}}0">;
+// CHECK: error: Duplicate enumerator name 'DName'
+
+#ifdef ERROR1
+def EnumValNotExpected : Error<"%enum_select{V1|%Val2{V2}}0">;
+// C1: expected '<' after enum_select
+#endif
+
+#ifdef ERROR2
+def SelectWithArrow : Error<"%select<Something>{V1|%Val2{V2}}0">;
+// C2: modifier '<' syntax not valid with %select
+#endif
+
+#ifdef ERROR3
+// Missing closing > after the name of the enumeration
+def MissingClosing : Error<"%enum_select<MissingClosingName{}0">;
+// C3: expected '>' while parsing %enum_select
+#endif
+
+#ifdef ERROR4
+// Missing { after the name of an enumerator
+def MissingTextAfterEnumerator: Error<"%enum_select<Name>{%OtherName|foo}0">;
+// C4: expected '{' while parsing %enum_select
+#endif
diff --git a/clang/test/TableGen/select-enum.td b/clang/test/TableGen/select-enum.td
diff --git a/clang/utils/TableGen/ClangDiagnosticsEmitter.cpp b/clang/utils/TableGen/ClangDiagnosticsEmitter.cpp
diff --git a/clang/utils/TableGen/TableGen.cpp b/clang/utils/TableGen/TableGen.cpp
diff --git a/clang/utils/TableGen/TableGenBackends.h b/clang/utils/TableGen/TableGenBackends.h
