• Paolo Severini's avatar
    Add initial support for Wasm debugging with LLDB: implements a GDB-remote stub · 03fc4149
    Paolo Severini authored
    This is the first piece of the wasm debugging prototype (besides the changes to
    add/remove breakpoints in WasmModuleObject made with
    https://chromium.googlesource.com/v8/v8.git/+/e699f39caed9a23f8e20bd3a0386a3236e272737).
    
    This changelist adds the infrastructure for a GDB-remote stub that will be used
    to manage debugging sessions via the gdb-remote protocol.
    It enables the creation and termination of debugging sessions over TCP
    connections that are managed in a separate thread.
    The logic to actually send, receive and decode GDB-remote packets will be part
    of a future changelist.
    
    Build with: v8_enable_wasm_gdb_remote_debugging = true
    Run with:
      --wasm-gdb-remote                  Enables Wasm debugging with LLDB
                                         (default: false)
      --wasm-gdb-remote-port             TCP port to be used for debugging
                                         (default: 8765)
      --wasm-pause-waiting-for-debugger  Pauses the execution of Wasm code waiting
                                         for a debugger (default: false)
      --trace-wasm-gdb-remote            Enables tracing of Gdb-remote packets
                                         (default: false)
    
    Note that most of this code is "borrowed" from the code of the Chromium NaCL
    GDB-remote stub (located in Chromium in src\native_client\src\trusted\debug_stub).
    
    Implementation details:
    - class GdbServer acts as a singleton manager for the gdb-remote stub. It is
      instantiated as soon as the first Wasm module is loaded in the Wasm engine.
    - class GdbServerThread spawns the worker thread for the TCP connection.
    - class Transport manages the socket connection, in a portable way.
    - class Session represents a remote debugging session.
    - class Target represents a debugging target and it’s the place where the
      debugging packets will be processed and will implement the logic to debug
      a Wasm engine.
    
    Bug: chromium:1010467
    Change-Id: Ib2324e5901f5ae1d855b96b99ef0995d407322b6
    Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1923407Reviewed-by: 's avatarClemens Backes <clemensb@chromium.org>
    Reviewed-by: 's avatarBenedikt Meurer <bmeurer@chromium.org>
    Reviewed-by: 's avatarMichael Achenbach <machenbach@chromium.org>
    Commit-Queue: Paolo Severini <paolosev@microsoft.com>
    Cr-Commit-Position: refs/heads/master@{#66379}
    03fc4149
gdb-server-thread.cc 3.49 KB