Plan for LLDB Fortran

Author: krystophny

BACKLOG.md

@@ -22,8 +22,9 @@
 
 ### Story 1.2: Test Infrastructure Foundation
 - [ ] Set up basic test structure in `lldb/test/API/lang/fortran/`
-- [ ] Create simple Fortran test programs (.f90 files)
-- [ ] Establish lit test configuration
+- [ ] Create simple Fortran test programs (.f90 files) with Makefile
+- [ ] Add Python test classes inheriting from `lldbsuite.test.TestBase`
+- [ ] Configure lit test discovery for Fortran API tests
 - [ ] Add CMake integration for Fortran tests
 
 **Acceptance Criteria**:
@@ -55,23 +56,27 @@
 
 ### Story 2.1: Plugin Registration Infrastructure (RED)
 - [ ] Create `lldb/source/Plugins/Language/Fortran/` directory structure
-- [ ] Implement basic `FortranLanguage.h` class declaration
-- [ ] Add plugin registration in PluginManager
+- [ ] Implement basic `FortranLanguage.h` class declaration inheriting from `Language`
+- [ ] Add `LLDB_PLUGIN_DEFINE(FortranLanguage)` macro
+- [ ] Register plugin with PluginManager using standard pattern
+- [ ] Add to `lldb/source/Plugins/Language/CMakeLists.txt`
 - [ ] Write failing test for language recognition
 
 **Acceptance Criteria**:
 - LLDB recognizes Fortran as a supported language
 - No "unsupported language" warnings for Fortran files
 - Plugin loads without errors
+- Follows LLVM coding standards (C++17, proper includes, naming)
 
 **Test Cases (RED phase)**:
 ```python
-# Test: test_fortran_language_recognition.py
-def test_fortran_language_detected(self):
-    """Test that LLDB recognizes Fortran source files"""
-    # This should FAIL initially
-    self.expect("settings show target.language", 
-                substrs=["fortran"])
+# Test: test_fortran_language_recognition.py (in lldb/test/API/lang/fortran/)
+class FortranLanguageTestCase(TestBase):
+    def test_fortran_language_detected(self):
+        """Test that LLDB recognizes Fortran source files"""
+        # This should FAIL initially
+        self.expect("settings show target.language", 
+                    substrs=["fortran"])
 ```
 
 ### Story 2.2: Language Type Recognition (GREEN)

CLAUDE.md

@@ -170,13 +170,18 @@ llvm-lit --filter="NamePattern" test/directory/
 
 **LLDB Build Configuration for Development:**
 ```bash
-# Minimal LLDB build for language plugin development
+# Recommended LLDB build for language plugin development
 cmake -S llvm -B build -G Ninja \
   -DLLVM_ENABLE_PROJECTS="clang;lldb;flang" \
   -DLLVM_TARGETS_TO_BUILD="X86" \
-  -DCMAKE_BUILD_TYPE=Debug \
+  -DCMAKE_BUILD_TYPE=RelWithDebInfo \
   -DLLVM_ENABLE_ASSERTIONS=ON \
-  -DLLDB_INCLUDE_TESTS=ON
+  -DLLDB_INCLUDE_TESTS=ON \
+  -DLLVM_INSTALL_UTILS=ON \
+  -DLLVM_USE_LINKER=lld
+
+# For debugging LLDB itself, use Debug instead of RelWithDebInfo
+# cmake -S llvm -B build -G Ninja -DCMAKE_BUILD_TYPE=Debug ...
 ```
 
 **LLDB Testing:**
@@ -198,9 +203,11 @@ lldb-dotest lldb/test/API/functionalities/breakpoint/
 **Language Plugin Development Pattern:**
 1. Create plugin directory: `lldb/source/Plugins/Language/LanguageName/`
 2. Implement `LanguageName.h` and `LanguageName.cpp` inheriting from `Language`
-3. Register plugin in `lldb/source/Plugins/Language/CMakeLists.txt`
-4. Add plugin initialization in appropriate registry
-5. Create tests in `lldb/test/API/lang/languagename/`
+3. Use `LLDB_PLUGIN_DEFINE(LanguageName)` macro for plugin definition
+4. Register with PluginManager in Initialize/Terminate methods
+5. Add to `lldb/source/Plugins/Language/CMakeLists.txt` using `add_subdirectory()`
+6. Create tests in `lldb/test/API/lang/languagename/` with proper Python test classes
+7. Follow LLVM coding standards: C++17, CamelCase types, lowerCamelCase variables
 
 **Key LLDB Classes for Language Plugins:**
 - `Language`: Base class for language-specific functionality
@@ -212,5 +219,14 @@ lldb-dotest lldb/test/API/functionalities/breakpoint/
 **Fortran Development Workflow:**
 - Use TDD: Write failing test first, implement to pass, refactor
 - Build only LLDB components: `ninja -C build lldb lldb-test`
-- Test frequently: `ninja -C build check-lldb-api-lang-fortran`
-- Use selective building to save time on large codebase
+- Test frequently: `llvm-lit lldb/test/API/lang/fortran/`
+- Format code: `git clang-format HEAD~1` before committing
+- Follow LLVM conventions: single commit per PR, no unrelated changes
+- Use selective building to save time on large codebase
+
+**LLVM Contribution Guidelines:**
+- Base patches on recent `main` branch commit
+- Include test cases with all patches
+- Format code with clang-format
+- Follow C++17 standards and LLVM data structures (SmallVector, DenseMap)
+- Use LLVM error handling (Expected<T>, Error) over exceptions

LLDB_FORTRAN.md

@@ -56,11 +56,11 @@ lldb/source/Plugins/Language/Fortran/
 ├── CMakeLists.txt
 ├── FortranLanguage.h
 ├── FortranLanguage.cpp
-├── FortranFormatters.h
-├── FortranFormatters.cpp
-└── FortranExpressionParser.h
+└── FortranFormatters.cpp
 ```
 
+**Plugin Registration**: Use `LLDB_PLUGIN_DEFINE(FortranLanguage)` macro and register with PluginManager following the pattern from CPlusPlusLanguage and ObjCLanguage.
+
 ### DWARF Integration Points
 
 Leverage existing Fortran-specific DWARF features:
@@ -127,18 +127,22 @@ Leverage existing Fortran-specific DWARF features:
 ## Build System Integration
 
 ### Selective Building Strategy
-Given the massive LLVM codebase, we need a minimal build configuration:
+Following LLVM best practices for focused development:
 
 ```bash
-# Minimal LLDB build for Fortran development
+# Recommended LLDB build for Fortran development
 cmake -S llvm -B build -G Ninja \
   -DLLVM_ENABLE_PROJECTS="clang;lldb;flang" \
   -DLLVM_TARGETS_TO_BUILD="X86" \
-  -DCMAKE_BUILD_TYPE=Debug \
+  -DCMAKE_BUILD_TYPE=RelWithDebInfo \
   -DLLVM_ENABLE_ASSERTIONS=ON \
-  -DLLDB_INCLUDE_TESTS=ON
+  -DLLDB_INCLUDE_TESTS=ON \
+  -DLLVM_INSTALL_UTILS=ON \
+  -DLLVM_USE_LINKER=lld
 ```
 
+**Note**: Using `RelWithDebInfo` provides better performance than `Debug` while maintaining debug symbols. Use `Debug` only when debugging LLDB itself.
+
 ### Test-Driven Development Workflow
 1. Write failing test for new functionality
 2. Implement minimal code to pass test