[fuchsia] Add debug symbols when running test suites

This also updates the Fuchsia debugging documentation instructions.

Bug: 1254560
Change-Id: I1351d47762504a41557f13caa2b3fc1794789bc2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3199373
Commit-Queue: Fabrice de Gans <[email protected]>
Reviewed-by: Kevin Marshall <[email protected]>
Cr-Commit-Position: refs/heads/main@{#928433}

build/fuchsia/common_args.py

@@ -83,6 +83,7 @@ def AddCommonArgs(arg_parser):
       help=('Path to the directory in which build files are located. '
             'Defaults to current directory.'))
   common_args.add_argument('--fuchsia-out-dir',
+                           default=None,
                            help='Path to a Fuchsia build output directory. '
                            'Setting the GN arg '
                            '"default_fuchsia_build_dir_for_installation" '

build/fuchsia/test_runner.py

@@ -13,10 +13,10 @@
 
 from common_args import AddCommonArgs, AddTargetSpecificArgs, \
                         ConfigureLogging, GetDeploymentTargetForArgs
+from deploy_to_pkg_repo import InstallSymbols
 from net_test_server import SetupTestServer
 from run_test_package import RunTestPackage, RunTestPackageArgs
 from runner_exceptions import HandleExceptionAndReturnExitCode
-from symbolizer import BuildIdsPaths
 
 DEFAULT_TEST_SERVER_CONCURRENCY = 4
 
@@ -221,6 +221,12 @@ def main():
         test_server = SetupTestServer(target, test_concurrency,
                                       args.package_name, test_realms)
 
+      if args.device is not None and args.fuchsia_out_dir is not None:
+        build_ids_path = os.path.join(args.fuchsia_out_dir, '.build-id')
+        for package in args.package:
+          InstallSymbols(os.path.join(os.path.dirname(package), 'ids.txt'),
+                         build_ids_path)
+
       run_package_args = RunTestPackageArgs.FromCommonArgs(args)
       if args.use_run_test_component:
         run_package_args.test_realm_label = TEST_REALM_NAME

docs/fuchsia/debug_instructions.md

@@ -1,49 +1,100 @@
 # Debugging
 
-It is possible to debug Fuchsia binaries using `zxdb`. For the sake of this
-example, we will be using `base_unittests` as the test suite we wish to execute:
+It is possible to debug Fuchsia binaries using `zxdb`. For the sake of these
+examples, we will be using `base_unittests` as the test suite we wish to
+execute. These instructions assume that your Chromium build has the following gn
+arguments:
+
+```
+is_debug = true
+is_component_build = true
+target_os = "fuchsia"
+symbol_level = 2
+```
+
+## Manual debugging via the command line
 
 1. (From Chromium) Install your package(s) and its symbols onto the device.
 
    ```bash
-   $ out/fuchsia/bin/install_base_unittests
+   out/fuchsia/bin/install_base_unittests --fuchsia-out-dir=/path/to/fuchsia/out/directory
    ```
 
 2. (From Fuchsia source tree) Run the debugger.
 
-  ```bash
-  $ fx debug
-  ```
+   ```bash
+   fx debug -- --build-dir /path/to/chromium/src/out/directory
+   ```
 
 3. Set up the debugger to attach to the process.
 
-  ```
-  [zxdb] attach base_unittests.cmx
-  ```
+   ```
+   [zxdb] attach base_unittests.cmx
+   ```
 
 4. Configure breakpoint(s).
 
-  ```
-  [zxdb] break base::GetDefaultJob
-  ```
+   ```
+   [zxdb] break base::GetDefaultJob
+   ```
 
 5. (In another terminal, from Fuchsia source tree) Run the test package.
 
-  ```bash
-  $ fx shell run fuchsia-pkg://fuchsia.com/base_unittests#meta/base_unittests.cmx
-  ```
+   ```bash
+   fx shell run fuchsia-pkg://fuchsia.com/base_unittests#meta/base_unittests.cmx
+   ```
 
 6. At this point, you should hit a breakpoint in `zxdb`.
 
-  ```
-  [zxdb] f
-  ▶ 0 base::GetDefaultJob() • default_job.cc:18
-    1 base::$anon::LaunchChildTestProcessWithOptions(…) • test_launcher.cc:335
-    2 base::$anon::DoLaunchChildTestProcess(…) • test_launcher.cc:528
-    3 base::TestLauncher::LaunchChildGTestProcess(…) • test_launcher.cc:877
-    ...
-  ```
+   ```
+   [zxdb] f
+   ▶ 0 base::GetDefaultJob() • default_job.cc:18
+     1 base::$anon::LaunchChildTestProcessWithOptions(…) • test_launcher.cc:335
+     2 base::$anon::DoLaunchChildTestProcess(…) • test_launcher.cc:528
+     3 base::TestLauncher::LaunchChildGTestProcess(…) • test_launcher.cc:877
+     ...
+   ```
 
 7. Enjoy debugging! Steps 2 through 6 will also work for things like services
    which aren't run directly from the command line, such as WebEngine.
-   Run `help` inside ZXDB to see what debugger commands are available.
+   Run `help` inside ZXDB to see what debugger commands are available.
+
+## VS Code integration
+
+1. Install the [zxdb](https://marketplace.visualstudio.com/items?itemName=fuchsia-authors.zxdb)
+   extension.
+
+2. Modify the `zxdb.command` setting in your Chromium workspace to this value:
+
+   ```bash
+   (cd /path/to/fuchsia ; fx debug -- --enable-debug-adapter --build-dir /path/to/chromium/src/out/directory)
+   ```
+
+3. Edit your debug launch configurations in `.vscode/launch.json`:
+
+   ```json
+   {
+       "version": "0.2.0",
+       "configurations": [
+           {
+               "name": "Attach to base_unittests",
+               "type": "zxdb",
+               "request": "attach",
+               "process": "base_unittests.cmx"
+           }
+       ]
+   }
+   ```
+
+   You can add more configurations as needed.
+
+4. Start the debug configuration in VS Code. You should get a terminal with zxdb
+   running.
+
+5. Launch the test suite in a terminal.
+
+   ```bash
+   out/fuchsia/bin/run_base_unittests -d --fuchsia-out-dir=/path/to/fuchsia/out/directory
+   ```
+
+6. Breakpoints set in the IDE should work.