[lldb] Fix off-by-one error in ToDwarfSourceLanguage

[joshpeterson]

The ToDwarfSourceLanguage function incorrectly excluded languages that equal eLanguageTypeLastStandardLanguage. The comparison used < instead of <=, causing the last standard language to fall through to the default case and return std::nullopt.

This broke language plugins that use eLanguageTypeLastStandardLanguage (currently Mojo at 0x0033) as their language code, preventing proper DWARF language conversion and breaking REPL functionality.

The fix changes the comparison from < to <= to include the last standard language in the automatic conversion to DWARF source language.

This is a regression from commit 7f51a2a which introduced the ToDwarfSourceLanguage function.

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[llvmbot]

@llvm/pr-subscribers-lldb

Author: Joshua Peterson (joshpeterson)

Changes

The ToDwarfSourceLanguage function incorrectly excluded languages that equal eLanguageTypeLastStandardLanguage. The comparison used < instead of <=, causing the last standard language to fall through to the default case and return std::nullopt.

This broke language plugins that use eLanguageTypeLastStandardLanguage (currently Mojo at 0x0033) as their language code, preventing proper DWARF language conversion and breaking REPL functionality.

The fix changes the comparison from < to <= to include the last standard language in the automatic conversion to DWARF source language.

This is a regression from commit 7f51a2a which introduced the ToDwarfSourceLanguage function.

---

Full diff: https://github.com/llvm/llvm-project/pull/162315.diff

1 Files Affected:

• (modified) lldb/source/Target/Language.cpp (+1-1)

diff --git a/lldb/source/Target/Language.cpp b/lldb/source/Target/Language.cpp
index 395718ecbe292..2efd4bc1e2c09 100644
--- a/lldb/source/Target/Language.cpp
+++ b/lldb/source/Target/Language.cpp
@@ -549,7 +549,7 @@ Language::~Language() = default;
 
 static std::optional<llvm::dwarf::SourceLanguage>
 ToDwarfSourceLanguage(lldb::LanguageType language_type) {
-  if (language_type < lldb::eLanguageTypeLastStandardLanguage)
+  if (language_type <= lldb::eLanguageTypeLastStandardLanguage)
     return static_cast<llvm::dwarf::SourceLanguage>(language_type);
 
   switch (language_type) {

[Michael137]

Thanks! Can we add a test to lldb/unittests/Target/Language.cpp? I think i skip a check there for eLanguageTypeLastStandardLanguage. Don't quite remember why that was.

[joshpeterson]

Thanks! Can we add a test to lldb/unittests/Target/Language.cpp? I think i skip a check there for eLanguageTypeLastStandardLanguage. Don't quite remember why that was.

Good suggestion, I'll do that.

[joshpeterson]

I've added a test at 3254a97. Please take a look, thanks!

[JDevlieghere]

LGTM

[Michael137]

LGTM (module last question)

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