How to debug c++ code using Bazel on Windows 10 OS

Question

Recently I start to play with the Bazel and I face a problem with debugging the app, I can debug with g++ but I can't debug the Bazel generated .exe file.

Thank you for looking on this.

Also, I build the source code with the Bazel and VsCode tasks.

1. What .exe file should I target to debug my application?
2. Is my setup Ok.?
3. It is possible to debug a c++ source code using Bazel on Windows.?
4. Should I use minGW for debugin a bazel generated executable or some othertools or debuggers.?

Versions

• OS: Windows 10
• Bazel version: Build label: 0.20.0

I have this project structure:

|-- CPP_TESTS
    |-- .gitignore
    |-- a.exe  <-- I generated this with g++ minGW
    |-- readme.md
    |-- WORKSPACE
    |-- .vscode
    |   |-- c_cpp_properties.json
    |   |-- launch.json
    |   |-- settings.json
    |   |-- tasks.json
    |-- project
        |-- WORKSPACE
        |-- main
            |-- app.cc
            |-- BUILD
            |-- readme.md

app.cc

#include <iostream>

int main(int argc, char const *argv[])
{
    int a = 3;
    int b = 5;
    int c = a + b;

    /* code */
    std::cout << "Hello world" << std::endl;
    std::cout << c << std::endl;
    return 0;
}

BUILD file

cc_binary(
    name = "app",
    srcs = ["app.cc"]
)

And then I run this command on the root of the ./CPP_TESTS

bazel build //project/main:app

this command will generate some files and folders

Some of the folders contain the app.exe file for example inside the bazel-bin dir I have this files and folder

|-- bazel-bin
    |-- project
    |   |-- main
    |       |-- app.exe
    |       |-- app.exe-2.params
    |       |-- app.exe.runfiles_manifest
    |       |-- app.pdb
    |       |-- app.exe.runfiles
    |       |   |-- MANIFEST
    |       |-- _objs
    |           |-- app
    |               |-- app.obj
    |-- project-name
        |-- main
            |-- app.exe
            |-- app.exe-2.params
            |-- app.exe.runfiles_manifest
            |-- app.pdb
            |-- app.exe.runfiles
            |   |-- MANIFEST
            |-- _objs
                |-- app
                    |-- app.obj

so If I run the app.exe inside the

|-- bazel-bin
    |-- project
    |   |-- main
    |       |-- app.exe   <=========

I get this output

INFO: Elapsed time: 0,145s, Critical Path: 0,01s
INFO: 0 processes.
INFO: Build completed successfully, 1 total action
INFO: Build completed successfully, 1 total action
Hello world
8
PS C:\dev\tests\cpp_tests>

if I debug the app I get this error.

before I start this is my tasks/json

{
    // See https://go.microsoft.com/fwlink/?LinkId=733558
    // for the documentation about the tasks.json format
    "version": "2.0.0",
    "tasks": [
        {
            "label": "bazel_run",
            "type": "shell",
            "command": "bazel run //project/main:app",
            "args": [],
            "group": {
                "kind": "build",
                "isDefault": true
            }
        },
        {
            "label": "bazel_build",
            "type": "shell",
            "command": "bazel build //project/main:app",
            "args": [],
            "group": {
                "kind": "build",
                "isDefault": true
            }
        },
        {
            "label": "bazel_debug_build",
            "type": "shell",
            "command": "bazel",
            "args": [
                "build",
                "//project/main:app",
                "--compilation_mode=dbg"
            ],
            "group": {
                "kind": "build",
                "isDefault": true
            },
            "problemMatcher": [
                "$gcc"
            ]
        }
    ]
}

launch.json

{
    // Use IntelliSense to learn about possible attributes.
    // Hover to view descriptions of existing attributes.
    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
    "version": "0.2.0",
    "configurations": [
        {                                
            "name": "(gdb) Launch",
            "type": "cppdbg",
            "request": "launch",
            // "program": "${workspaceFolder}/a.exe",
            "program": "${workspaceFolder}\\bazel-bin\\project\\main\\app.exe",
            "args": [],
            "stopAtEntry": false,
            "cwd": "${workspaceFolder}",
            "environment": [],
            "externalConsole": true,
            "MIMode": "gdb",
            "miDebuggerPath": "C:/MinGW/bin/gdb.exe",
            "preLaunchTask": "bazel_debug_build",
            "setupCommands": [
                {
                    "description": "Enable pretty-printing for gdb",
                    "text": "-enable-pretty-printing",
                    "ignoreFailures": true
                }
            ]
        }
    ]
}

So I run the bazel build //project/main:app command

Error message.

But the app.exe is there?

Answer 1

First, you need to add some bazel options to debug. Manual is in here:enter link description here

If you want to debug your program, you need and options such as:

bazel build --copt="-g" --strip="never" ... 

Answer 2

You should use the executable located in the build folder bazel-out/x64_windows-dbg/project/main/app.exe.

If you are setting breakpoints, you may need the --strip=never argument as well.

If it does not work, try "cppvsdbg" rather than "cppdbg" as configuration type in your launch.json.

Answer 3

Please see my answer on the related question: https://stackoverflow.com/a/54007919/7778502

While I can't tell whether your setup is correct (I'd need to know more, such as what VSCode plugins you have installed, what's the content of the other .json files), I can say for sure that it looks wrong that you have two WORKSPACE files.

You should remove project\WORKSPACE, because Bazel considers every directory tree with a WORKSPACE file to be a unique workspace. Every workspace needs just one WORKSPACE file in its root directory. If a subdirectory has its own WORKSPACE file, then it's a separate workspace, and Bazel won't use targets from it in the "parent" workspace.