Re: Running ghc-debug on ghc

This looks really cool! So it’s like a debugger that can also do heap introspection profiling as a consequence of being able to inspect the state as part of debugging? On Tue, Mar 9, 2021 at 10:23 AM Matthew Pickering < matthewtpickering@gmail.com> wrote:

Hi,

I now have some simple instructions for running ghc-debug on GHC.

1. Cherry-pick 4be70967f1f1ab70cbe31aad8ae69aea87c6f4c4

commit 4be70967f1f1ab70cbe31aad8ae69aea87c6f4c4 (HEAD -> wip/ghc-with-debug) Author: Matthew Pickering Date: Fri Jan 8 11:26:17 2021 +0000

Add support for ghc-debug to ghc executable

2. Build GHC * Add the following to _build/hadrian.settings

``` stage1.*.ghc.hs.opts += -finfo-table-map -fdistinct-constructor-tables ```

* Build GHC as normal

``` ./hadrian/build -j8 ```

* The result is a ghc-debug enabled compiler

# Building a debugger

* Use the compiler you just built to build ghc-debug

``` cd ghc-debug cabal update cabal new-build debugger -w ../_build/stage1/bin/ghc ```

# Running the debugger

Modify `test/Test.hs` to implement the debugging thing you want to do. Perhaps start with `p30`, which is a program to generate a profile.

* Start the process you want to debug ``` GHC_DEBUG_SOCKET=/tmp/ghc-debug build-cabal ```

* Start the debugger ``` cabal new-run debugger -w ... ```

* Open a ticket about the memory issue you find.

There is the start of some more documentation here - http://ghc.gitlab.haskell.org/ghc-debug/docs.html

These instructions are also in the instructions.md file in the commit.

Cheers,

Matt _______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs