This changelist makes the GDB-stub actually execute GDB-remote commands, by
accessing the Wasm engine state. More precisely:
- class GdbServer registers DebugDelegates that receive debug notifications when
a new Wasm module is loaded, when execution suspends at a breakpoint or for an
unhandled exception.
- Since the GDB-remote commands arrive on a separate thread, all
queries from the debugger are transformed into Task objects, that are posted
into a TaskRunner that runs in the Isolate thread.
- class WasmModuleDebug contains the logic to retrieve the value of globals, locals, memory ranges from the
Wasm engine and to add/remove breakpoints.
Build with: v8_enable_wasm_gdb_remote_debugging = true
Run with: --wasm-gdb-remote
Test with: python tools\run-tests.py --outdir=out\debug_x64 debugging -j 1
Bug: chromium:1010467
Change-Id: I9703894620a027d3c920926db92e2ff809d84ab8
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1941139
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Paolo Severini <paolosev@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#67412}
This is the first piece of the wasm debugging prototype (besides the changes to
add/remove breakpoints in WasmModuleObject made with
e699f39cae).
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/+/1923407
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Paolo Severini <paolosev@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#66379}
