[Lldb-commits] [clang] [lldb] [lldb] Re-use clang's keyword enable/disable mechanism in CPlusPlusNameParser.cpp (PR #164284)

via lldb-commits lldb-commits at lists.llvm.org
Mon Oct 20 10:25:56 PDT 2025


llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Daniel Sanders (dsandersllvm)

<details>
<summary>Changes</summary>

The problem is that CPlusPlusNameParser doesn't respect the language dialect for `target variable Class::constant`. If `constant` is a keyword in some (downstream in this case) dialects then it lexes `constant` as `kw_constant` instead of `kw_raw_identifier` even if that dialect is not active. As a result:
* `target variable constant` works
* `target variable Class::constant` fails to look up constant because it sees `kw_raw_identifier, kw_coloncolon, kw_constant` instead of `kw_raw_identifier, kw_coloncolon, kw_raw_identifier`
* `expr -l c++ -- Class::constant` works because clang is parsing it

Note: There's seemingly a separate bug where GetLangOptions() does not account for the process/frame language and just uses a pre-defined set of language options. I have not attempted to fix that since, for now, at least hardcoding my dialect to be disabled by that function does the right thing for existing tests.

Also fixed a trivial return-after-else that clangd pointed out in the same area

---
Full diff: https://github.com/llvm/llvm-project/pull/164284.diff


3 Files Affected:

- (modified) clang/include/clang/Basic/IdentifierTable.h (+53) 
- (modified) clang/lib/Basic/IdentifierTable.cpp (+1-52) 
- (modified) lldb/source/Plugins/Language/CPlusPlus/CPlusPlusNameParser.cpp (+13-7) 


``````````diff
diff --git a/clang/include/clang/Basic/IdentifierTable.h b/clang/include/clang/Basic/IdentifierTable.h
index e4044bcdfcc60..8177029f13ca9 100644
--- a/clang/include/clang/Basic/IdentifierTable.h
+++ b/clang/include/clang/Basic/IdentifierTable.h
@@ -46,6 +46,59 @@ class LangOptions;
 class MultiKeywordSelector;
 class SourceLocation;
 
+// This is an inline namespace to allow both clang and lldb to use them without
+// namespace prefixes (via `using namespace` in lldb's case).
+inline namespace TokenKeyEnumerators {
+enum TokenKey : unsigned {
+  KEYC99 = 0x1,
+  KEYCXX = 0x2,
+  KEYCXX11 = 0x4,
+  KEYGNU = 0x8,
+  KEYMS = 0x10,
+  BOOLSUPPORT = 0x20,
+  KEYALTIVEC = 0x40,
+  KEYNOCXX = 0x80,
+  KEYBORLAND = 0x100,
+  KEYOPENCLC = 0x200,
+  KEYC23 = 0x400,
+  KEYNOMS18 = 0x800,
+  KEYNOOPENCL = 0x1000,
+  WCHARSUPPORT = 0x2000,
+  HALFSUPPORT = 0x4000,
+  CHAR8SUPPORT = 0x8000,
+  KEYOBJC = 0x10000,
+  KEYZVECTOR = 0x20000,
+  KEYCOROUTINES = 0x40000,
+  KEYMODULES = 0x80000,
+  KEYCXX20 = 0x100000,
+  KEYOPENCLCXX = 0x200000,
+  KEYMSCOMPAT = 0x400000,
+  KEYSYCL = 0x800000,
+  KEYCUDA = 0x1000000,
+  KEYZOS = 0x2000000,
+  KEYNOZOS = 0x4000000,
+  KEYHLSL = 0x8000000,
+  KEYFIXEDPOINT = 0x10000000,
+  KEYMAX = KEYFIXEDPOINT, // The maximum key
+  KEYALLCXX = KEYCXX | KEYCXX11 | KEYCXX20,
+  KEYALL = (KEYMAX | (KEYMAX - 1)) & ~KEYNOMS18 & ~KEYNOOPENCL &
+           ~KEYNOZOS // KEYNOMS18, KEYNOOPENCL, KEYNOZOS are excluded.
+};
+} // namespace TokenKeyEnumerators
+
+/// How a keyword is treated in the selected standard. This enum is ordered
+/// intentionally so that the value that 'wins' is the most 'permissive'.
+enum KeywordStatus {
+  KS_Unknown,   // Not yet calculated. Used when figuring out the status.
+  KS_Disabled,  // Disabled
+  KS_Future,    // Is a keyword in future standard
+  KS_Extension, // Is an extension
+  KS_Enabled,   // Enabled
+};
+
+KeywordStatus getKeywordStatus(const LangOptions &LangOpts,
+                               unsigned Flags);
+
 enum class ReservedIdentifierStatus {
   NotReserved = 0,
   StartsWithUnderscoreAtGlobalScope,
diff --git a/clang/lib/Basic/IdentifierTable.cpp b/clang/lib/Basic/IdentifierTable.cpp
index 4a2b77cd16bfc..65ed1273350c5 100644
--- a/clang/lib/Basic/IdentifierTable.cpp
+++ b/clang/lib/Basic/IdentifierTable.cpp
@@ -77,57 +77,6 @@ IdentifierTable::IdentifierTable(const LangOptions &LangOpts,
 // Language Keyword Implementation
 //===----------------------------------------------------------------------===//
 
-// Constants for TokenKinds.def
-namespace {
-
-enum TokenKey : unsigned {
-  KEYC99 = 0x1,
-  KEYCXX = 0x2,
-  KEYCXX11 = 0x4,
-  KEYGNU = 0x8,
-  KEYMS = 0x10,
-  BOOLSUPPORT = 0x20,
-  KEYALTIVEC = 0x40,
-  KEYNOCXX = 0x80,
-  KEYBORLAND = 0x100,
-  KEYOPENCLC = 0x200,
-  KEYC23 = 0x400,
-  KEYNOMS18 = 0x800,
-  KEYNOOPENCL = 0x1000,
-  WCHARSUPPORT = 0x2000,
-  HALFSUPPORT = 0x4000,
-  CHAR8SUPPORT = 0x8000,
-  KEYOBJC = 0x10000,
-  KEYZVECTOR = 0x20000,
-  KEYCOROUTINES = 0x40000,
-  KEYMODULES = 0x80000,
-  KEYCXX20 = 0x100000,
-  KEYOPENCLCXX = 0x200000,
-  KEYMSCOMPAT = 0x400000,
-  KEYSYCL = 0x800000,
-  KEYCUDA = 0x1000000,
-  KEYZOS = 0x2000000,
-  KEYNOZOS = 0x4000000,
-  KEYHLSL = 0x8000000,
-  KEYFIXEDPOINT = 0x10000000,
-  KEYMAX = KEYFIXEDPOINT, // The maximum key
-  KEYALLCXX = KEYCXX | KEYCXX11 | KEYCXX20,
-  KEYALL = (KEYMAX | (KEYMAX - 1)) & ~KEYNOMS18 & ~KEYNOOPENCL &
-           ~KEYNOZOS // KEYNOMS18, KEYNOOPENCL, KEYNOZOS are excluded.
-};
-
-/// How a keyword is treated in the selected standard. This enum is ordered
-/// intentionally so that the value that 'wins' is the most 'permissive'.
-enum KeywordStatus {
-  KS_Unknown,   // Not yet calculated. Used when figuring out the status.
-  KS_Disabled,  // Disabled
-  KS_Future,    // Is a keyword in future standard
-  KS_Extension, // Is an extension
-  KS_Enabled,   // Enabled
-};
-
-} // namespace
-
 // This works on a single TokenKey flag and checks the LangOpts to get the
 // KeywordStatus based exclusively on this flag, so that it can be merged in
 // getKeywordStatus. Most should be enabled/disabled, but some might imply
@@ -222,7 +171,7 @@ static KeywordStatus getKeywordStatusHelper(const LangOptions &LangOpts,
 
 /// Translates flags as specified in TokenKinds.def into keyword status
 /// in the given language standard.
-static KeywordStatus getKeywordStatus(const LangOptions &LangOpts,
+KeywordStatus clang::getKeywordStatus(const LangOptions &LangOpts,
                                       unsigned Flags) {
   // KEYALL means always enabled, so special case this one.
   if (Flags == KEYALL) return KS_Enabled;
diff --git a/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusNameParser.cpp b/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusNameParser.cpp
index d8c095d6edeb7..13cea5e513005 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusNameParser.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusNameParser.cpp
@@ -719,9 +719,8 @@ CPlusPlusNameParser::ParseFullNameImpl() {
     }
     start_position.Remove();
     return result;
-  } else {
-    return std::nullopt;
   }
+  return std::nullopt;
 }
 
 llvm::StringRef CPlusPlusNameParser::GetTextForRange(const Range &range) {
@@ -755,12 +754,19 @@ static const clang::LangOptions &GetLangOptions() {
   return g_options;
 }
 
-static const llvm::StringMap<tok::TokenKind> &GetKeywordsMap() {
-  static llvm::StringMap<tok::TokenKind> g_map{
-#define KEYWORD(Name, Flags) {llvm::StringRef(#Name), tok::kw_##Name},
+static const llvm::StringMap<tok::TokenKind> GetKeywordsMap() {
+  using namespace clang::TokenKeyEnumerators;
+  llvm::StringMap<tok::TokenKind> g_map;
+
+  auto LangOpts = GetLangOptions();
+
+  clang::KeywordStatus AddResult;
+#define KEYWORD(NAME, FLAGS)                                                   \
+  AddResult = getKeywordStatus(LangOpts, FLAGS);                               \
+  if (AddResult != clang::KS_Disabled)                                         \
+    g_map[llvm::StringRef(#NAME)] = tok::kw_##NAME;
 #include "clang/Basic/TokenKinds.def"
 #undef KEYWORD
-  };
   return g_map;
 }
 
@@ -769,7 +775,7 @@ void CPlusPlusNameParser::ExtractTokens() {
     return;
   clang::Lexer lexer(clang::SourceLocation(), GetLangOptions(), m_text.data(),
                      m_text.data(), m_text.data() + m_text.size());
-  const auto &kw_map = GetKeywordsMap();
+  const auto kw_map = GetKeywordsMap();
   clang::Token token;
   for (lexer.LexFromRawLexer(token); !token.is(clang::tok::eof);
        lexer.LexFromRawLexer(token)) {

``````````

</details>


https://github.com/llvm/llvm-project/pull/164284


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