4. Explore C++ code intelligence#

Sense’s integration with pw_ide enables fast and accurate code navigation, autocompletion based on a deep understanding of the code structure, and instant compiler warnings and errors. Try the code navigation now:

  1. Press Control+Shift+P (Command+Shift+P on macOS) to open the Command Palette.

  2. Start typing Pigweed: Select Code Analysis Target and press Enter to start executing that command.

    https://storage.googleapis.com/pigweed-media/sense/20240802/target.png

    Tip

    You can also select code analysis targets from the bottom-left of your VS Code GUI, in the status bar. In the next image, the mouse cursor is hovering over the GUI element for selecting code analysis targets.

    https://storage.googleapis.com/pigweed-media/sense/20240802/select_target_status_bar.png

  3. Select the rp2040 option.

    Tip

    In the status bar (the bar at the bottom of VS Code) you may see informational messages about clang indexing. You don’t need to wait for that indexing to complete.

    The code intelligence is now set up to help you with physical Pico programming. If you had selected the other option, host_simulator, the code intelligence would be set up to help with programming the simulated app that you will run on your development host in 6. Run the host app. Verify the platform-specific code intelligence now by making sure that pw_log invocations resolve to different backends.

  4. Open //apps/blinky/main.cc.

  5. Right-click the PW_LOG_INFO() invocation and select Go to Definition.

    Selecting "Go to Definition" after right-clicking PW_LOG_INFO()

    This should take you to a file called log.h:

    #ifndef PW_LOG_INFO
#define PW_LOG_INFO(...) \  // Your cursor should be on this line.
  PW_LOG(PW_LOG_LEVEL_INFO, PW_LOG_MODULE_NAME, PW_LOG_FLAGS, __VA_ARGS__)
#endif  // PW_LOG_INFO

  6. Right-click the PW_LOG() invocation (on the line below your cursor) and select Go to Definition again. You should jump here:

    #ifndef PW_LOG
#define PW_LOG(  // Your cursor should be on this line.
  // ...
      PW_HANDLE_LOG(level, module, flags, __VA_ARGS__);
  // ...

  7. Finally, right-click the PW_HANDLE_LOG() invocation and select Go to Definition one last time. You should jump to a pw_log_tokenized backend header. You can hover over the filename in the tab (log_backend.h) to see the full path to the header.

  8. Open the Command Palette, switch your target to host_simulator, and then repeat this Go to Definition workflow again, starting from //apps/blinky/main.cc. You should see the definitions finally resolve to a pw_log_string backend header.

    This proves that code intelligence is working because the original call to PW_LOG_INFO() in //apps/blinky/main.cc is basically a generic API that gets resolved at compile-time. The resolution depends on what platform you’re building for (rp2040 or host_simulator). See Facades & backends.

Here’s a diagram summary of how the code intelligence resolved to different files depending on the code analysis target you selected:

flowchart LR a["main.cc"] --> b["log.h"] b["log.h"] -. rp2040 .-> c["pw_log_tokenized/.../log_backend.h"] b["log.h"] -. host_simulator .-> d["pw_log_string/.../log_backend.h"]

This feature is only supported in VS Code.

Summary#

Portable, hardware-agnostic software abstractions such as pw_log make it easier to reuse code across projects and hardware platforms. But they also make it more difficult to correctly navigate references in your codebase. The Pigweed extension for VS Code can solve this problem; you just need to tell it what hardware platform within your codebase it should focus on.

Next, head over to 5. Run host tests to learn how to run unit tests on your development host so that you can verify that Sense’s logic is correct before attempting to run it.

On this page