Embecosm Debug Server

This contains the source for the Embecosm Debug Server which can be used alongside GDB or LLDB to debug bare-metal targets.

The Embecosm Debug Server is open source and available under the GPLv3+ license, with an exception for the target interface, which is available under the MIT license. The terms of the license can be found in LICENSE.

Minimum requirements

MSVC 2015, Clang 3.4, or GCC 5
cmake 3.4.3

Building the debug server without a target

_NOTE: These are basic steps to build the debug server however this does not include a target for the server, which in this case would need to be built separately. See below for building the server and the target in a single step.

A more complete guide with an example target (ri5cy for a 32-bit RISC-V system) can be found in:_ docs/Ri5cyTutorial

The cmake build system is used to build the project. Running the follow steps from the build directory are sufficient to build and install the debug server:

cmake -DCMAKE_INSTALL_PREFIX=<install_dir> <source_dir>
cmake --build .
cmake --build . --target install

The result of the build is the embdebug program, which is used to start a server which GDB or LLDB can connect to.

Build options

This is a quick reference for options which can be provided to cmake:

Flag	Description
`-DCMAKE_INSTALL_PREFIX`	Directory the debug server will be installed to.
`-DEMBDEBUG_ENABLE_WERROR`	Enable `-Werror` (or equivalent) when building
`-DEMBDEBUG_ENABLE_DOXYGEN`	Enable generation of API docs using `doxygen`.
`-DEMBDEBUG_ENABLE_DOCS`	Enable generation of project documentation using `sphinx`
`-DEMBDEBUG_TARGETS_TO_BUILD`	Comma separated list of directories in `targets/` to be built alongside the debug server.

For more complete build options, see docs/Building

Building the debug server with a target

To build the target as well as the server, you just need to link the source tree of the target into the targets directory of Embdebug. The target should use Cmake for configuration, and have its own CMakeLists.txt at the top level.

Build and configure is then identical to the steps for the debug server without a target. The only change is that you can also add build options specific to the target to the initial cmake command.

Running

The debug server can be started with the following command:

embdebug --soname <libtarget.so> --rsp-port <port_number>

This will expose a debug server on the provided port which can be connected to from GDB or LLDB.

For more detail about options to the embdebug command, see docs/Running

Connecting to a local debug server

To connect with the debug server, first it needs to be running locally:

embdebug --soname <libtarget.so> --rsp-port <port_number>

Now the debug server is waiting for a connection from a debugger. Attaching from the debugger depends on the debugger being used.

Connecting from GDB

(gdb) target remote :<port_number>

or using the pipe interface

(gdb) target remote |embdebug -s <soname>

(you can add any other embdebug command line options).

Connecting from LLDB

(lldb) gdb-remote <port_number>

Run options

A quick reference for options which can be provided to embdebug:

Flag	Description
`--rsp-port <portnum>`	Port number that the debugger will connect to.
`--soname <shared_object>`	Shared object containing a target exposing the target interface.
`--version`	Print the version number of the debug server.
`--stdin`	Communicate with the debugger over standard input/output instead of over a socket.

Testing

The debug server contains a test suite which can be executed using gtest:

cmake --build . --target test

chuanjinpang/gdbserver_general