Espressif-IDE LSP Support for C/C++ Editor

[中文]

The Espressif-IDE 3.0.0 or later now includes the Eclipse CDT-LSP, enabling support for the latest C/C++ standards and providing an LSP-based C/C++ Editor. This editor, powered by the LLVM clangd C/C++ language server, offers advanced functionality for ESP-IDF developers.

In line with this enhancement, we have discontinued support for the standard CDT Editor/Indexer, as it only supports up to C++ 14. This has been replaced with a new LSP editor, especially considering that ESP-IDF now utilizes C++ 20 (with GCC 11.2) in v5.0.x, transitions to C++ 23 (with GCC 12.1) in v5.1, and to C++ 23 (with GCC 13.1) in v5.2.

The LSP powered C/C++ editor greatly benefits ESP-IDF developers by aligning with the latest language standards and compiler versions, enhancing productivity, and improving code quality.

You can find more details on the LSP based C/C++ editor features in the documentation of the Eclipse cdt-lsp repository.

Prerequisites

• You need Espressif-IDE 3.0.0 or later to access the LSP-powered C/C++ editor.

• If you are updating Eclipse CDT or Espressif-IDE via the update site, you need to select the ESP-IDF Eclipse Plugin and its dependencies, as shown below:

  

Clangd Configuration

By default, the esp-clang toolchain is installed as a part of the ESP-IDF tools installation process, and clangd Path is configured in the preferences.

The Drivers path and --compile-commands-dir path will be configured based on the selected target (esp32, esp32c6, etc.) and the project being built.

However, if there are any issues in configuration, this can be configured in the following way:

1. Go to Window > Preferences > C/C++ > Editor(LSP).

2. Navigate to clangd node.

3. Provide Drivers path as shown in the screenshot.

4. Set --compile-commands-dir=/project/build in the additional argument section.

5. Click on Apply and Close.

   

By default, when you create a new project, a .clangd configuration file is generated automatically.

If you are migrating a project from an older version, you need to create a .clangd file manually in the project root and add the following content:

CompileFlags:
    CompilationDatabase: build
    Remove: [-m*, -f*]

How to Fix the “Unknown Argument” Error When Navigating to ESP-IDF Components

If you see the following error markers while navigating to the ESP-IDF component source code:

Multiple markers at this line
- Unknown argument: '-fno-tree-switch-conversion' [drv_unknown_argument]
- Unknown argument: '-fno-shrink-wrap' [drv_unknown_argument]
- Unknown argument: '-fstrict-volatile-bitfields' [drv_unknown_argument]

Please follow the steps below to fix it:

1. Download the script fix_compile_commands.py.

2. Invoke the script from the project post build step. Here is example for CMakeLists.txt:

   if(EXISTS "${CMAKE_SOURCE_DIR}/fix_compile_commands.py")
       add_custom_target(
           fix_clangd ALL
           COMMAND ${CMAKE_COMMAND} -E echo "Running fix_compile_commands.py..."
           COMMAND ${CMAKE_COMMAND} -E env python3 ${CMAKE_SOURCE_DIR}/fix_compile_commands.py
           COMMENT "Cleaning compile_commands.json for clangd"
           VERBATIM
       )
   endif()
   

3. Run the build, the script will remove the -m* and -f* flags from the compile_commands.json file which are unknown to clangd.

4. Now, you can navigate to the ESP-IDF components source code without any errors.

Disable CDT Indexer

With Espressif-IDE 3.0.0 or later, the CDT Indexer is disabled by default; instead, the LSP Indexer server is used for code analysis.

If, for any reason, it is not disabled, follow the steps below to disable it.

1. Go to Window > Preferences > C/C++ > Indexer.

2. Uncheck Enable Indexer option and then click on Apply and Close.