Gcov (Source Code Coverage)

[中文]

Gcov is a source code coverage analysis tool. In ESP-IDF, coverage data generated on the target is dumped to the host over apptrace (JTAG or UART), where it is turned into standard .gcda files and processed with the usual host-side tools.

Report generation also needs the .gcno notes files that the compiler generates at build time for each source compiled with --coverage. The host-side tools combine the runtime .gcda counts with the .gcno files and the original sources to produce the coverage report.

Gcov uses the tracing infrastructure for host data transfer, but it does not yet fully follow the esp_trace encoder/transport model. In particular, it is tied to the apptrace transport (JTAG or UART) and does not support selecting a custom transport.

Coverage support is provided by the managed component espressif/esp_gcov. Add it to your project's idf_component.yml:

dependencies:
  espressif/esp_gcov: ^1

Coverage data can be dumped either at a hard-coded point in your application (over apptrace via JTAG or UART) or on demand from the host via the OpenOCD esp gcov command (JTAG only). For the full setup, configuration options, and command usage, see README of the component linked above.

Application Example

  • system/gcov demonstrates how to add code coverage to a project and collect coverage data over JTAG.

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