Move GHC from source to its own topic, online

mpilgrem · mpilgrem · commit ca76ced74146 · 2025-11-13T21:58:49.000Z
diff --git a/doc/configure/global_flags.md b/doc/configure/global_flags.md
@@ -174,8 +174,8 @@ for the [`skip-msys`](yaml/non-project.md#skip-msys) configuration option.
 Pass the option `--jobs <number_of_jobs>` to specify the number of concurrent
 jobs (Stack actions during building) to run.
 
-When [building GHC from source](yaml/non-project.md#building-ghc-from-source),
-specifies the `-j[<n>]` flag of GHC's Hadrian build system.
+When [building GHC from source](../topics/GHC_from_source.md), specifies the
+`-j[<n>]` flag of GHC's Hadrian build system.
 
 By default, Stack specifies a number of concurrent jobs equal to the number of
 CPUs (cores) that the machine has. In some circumstances, that default can cause
diff --git a/doc/configure/yaml/non-project.md b/doc/configure/yaml/non-project.md
@@ -305,164 +305,13 @@ compiler: ghc-9.8.3
 compiler-check: match-exact
 ~~~
 
-### Building GHC from source
-
 :octicons-beaker-24: Experimental
 
 [:octicons-tag-24: 2.1.1](https://github.com/commercialhaskell/stack/releases/tag/v2.1.1)
 
-Stack supports building the GHC compiler from source, using
-[Hadrian](https://gitlab.haskell.org/ghc/ghc/blob/master/hadrian/README.md) (the
-build system for GHC). The GHC version to build and to use is defined by a a Git
-commit ID and a Hadrian "flavour", with the following syntax:
-
-~~~yaml
-compiler: ghc-git-<commit_id>-<Hadrian_flavour>
-~~~
-
-In the following example the commit ID is "5be7ad..." and the flavour is
-"quick":
-
-~~~yaml
-compiler: ghc-git-5be7ad7861c8d39f60b7101fd8d8e816ff50353a-quick
-~~~
-
-By default, the code is retrieved from the main GHC repository. If you want to
-select another repository, use the `compiler-repository` option:
-
-~~~yaml
-compiler-repository: git://my/ghc/repository
-# default
-# compiler-repository: https://gitlab.haskell.org/ghc/ghc.git
-~~~
-
-Stack does not check the compiler version when it uses a compiler built from
-source. It is assumed that the built compiler is recent enough as Stack does not
-enable any known workaround to make older compilers work.
-
-Building the compiler can take a very long time (more than one hour). For faster
-build times, use Hadrian flavours that disable documentation generation.
-
-### Bootstrap compiler
-
-Building GHC from source requires a working GHC (known as the bootstrap
-compiler). As we use a Stack based version of Hadrian (`hadrian/build-stack` in
-GHC sources), the bootstrap compiler is configured into `hadrian/stack.yaml` and
-fully managed by Stack.
-
-!!! note
-
-    For some commit IDs, the snapshot specified in `hadrian/stack.yaml`
-    specifies a version of GHC that cannot be used to build GHC. This results in
-    GHC's `configure` script reporting messages similar to the following before
-    aborting:
-
-    ~~~text
-    checking version of ghc... 9.0.2
-    configure: error: GHC version 9.2 or later is required to compile GHC.
-    ~~~
-
-    The resolution is: (1) to specify an alternative snapshot (one that
-    specifies a sufficiently recent version of GHC) on the command line, using
-    Stack's option `--snapshot <snapshot>`. Stack will use that snapshot when
-    running GHC's `configure` script; and (2) to set the contents of the `STACK`
-    environment variable to be `stack --snapshot <snapshot>`. Hadrian's
-    `build-stack` script wil refer to that environment variable for the Stack
-    command it uses.
-
-### Hadrian prerequisites
-
-The Hadrian build system has certain
-[prerequisites](https://gitlab.haskell.org/ghc/ghc/-/wikis/building/preparation).
-It requires certain versions of the `happy` and `alex` executables on the PATH.
-Stack will build and install `happy` and `alex`, if not already on the PATH.
-
-=== "macOS"
-
-    Hadrian requires, or case use, certain tools or Python packages that do not
-    come with macOS by default and that need to be installed using `brew` or
-    `pip3` (Python). Hadrian's LaTeX documentation also requires the
-    [DejaVu fonts](https://dejavu-fonts.github.io/) to be installed.
-
-    ~~~zsh
-    brew install python@3.11
-    # GHC uses a Python script named `boot`.
-    brew install automake
-    # Tool for generating GNU Standards-compliant Makefiles.
-    brew install texinfo
-    # Official documentation format of the GNU project.
-    pip3 install -U sphinx
-    # Sphinx is the Python documentation generator.
-    brew install --cask mactex
-    # MacTeX: Full TeX Live distribution with GUI applications
-    ~~~
-
-=== "Windows"
-
-    Hadrian requires, or can use, certain MSYS2 or Python packages that do not
-    come with the Stack-supplied MSYS2 by default and need to be installed
-    using `pacman` (MSYS2) or `pip` (Python). Hadrian's LaTeX documentation also
-    requires the [DejaVu fonts](https://dejavu-fonts.github.io/) to be
-    installed.
-
-    ~~~pwsh
-    stack exec -- pacman --sync --refresh
-    # Synchronize MSYS2 package databases
-    stack exec -- pacman --sync mingw-w64-x86_64-python-pip
-    # The PyPA recommended tool (pip) for installing Python packages. Also
-    # installs Python as a dependency. GHC uses a Python script named `boot`.
-    # The package must be the one from the `mingw64` MSYS2 repository, as Python
-    # from the `msys` repository cannot interpret Windows file paths correctly.
-    stack exec -- pacman --sync mingw-w64-x86_64-autotools
-    # The GNU autotools build system, including `autoreconf`, `aclocal`
-    # and `make`. GHC uses a sh script named `configure` which is itself created
-    # from a file named `configure.ac`.
-    stack exec -- pacman --sync patch
-    # A utility to apply patch files to original sources.
-    stack exec -- pacman --sync texinfo
-    # Utilities to work with and produce manuals, ASCII text, and on-line
-    # documentation from a single source file, including `makeinfo`.
-    stack exec -- pacman --sync mingw-w64-x86_64-ca-certificates
-    # Common CA (certificate authority) certificates.
-    stack exec -- pip install -U sphinx
-    # Sphinx is the Python documentation generator.
-    ~~~
-
-    Hadrian may require certain LaTeX packages and may prompt for these to be
-    installed duing the build process.
-
-### Global packages
-
-The GHC compiler you build from sources may depend on unreleased versions of
-some global packages (e.g. Cabal). It may be an issue if a package you try to
-build with this compiler depends on such global packages because Stack may not
-be able to find versions of those packages (on Hackage, etc.) that are
-compatible with the compiler.
-
-The easiest way to deal with this issue is to use the
-[`drop-packages`](project.md#drop-packages) project-specific configuration
-option to drop the offending packages as follows. Instead of using the packages
-specified in the snapshot, the global packages bundled with GHC will be used.
-
-~~~yaml
-drop-packages:
-- Cabal
-- ...
-~~~
-
-Another way to deal with this issue is to add the relevant packages as
-[`extra-deps`](project.md#extra-deps) built from source. To avoid mismatching
-versions, you can use exactly the same commit id you used to build GHC as
-follows:
-
-~~~
-extra-deps:
-- git: https://gitlab.haskell.org/ghc/ghc.git
-  commit: '5be7ad7861c8d39f60b7101fd8d8e816ff50353a'
-  subdirs:
-    - libraries/Cabal/Cabal
-    - libraries/...
-~~~
+Stack also supports building the GHC compiler from source. For further
+information, see the [building GHC from source](../../topics/GHC_from_source.md)
+documentation.
 
 ## compiler-check
 
@@ -915,7 +764,7 @@ Command line equivalent (takes precedence):
 Specifies the number of concurrent jobs (principally, Stack actions during
 building - see further below) to run.
 
-When [building GHC from source](#building-ghc-from-source), specifies the
+When [building GHC from source](../../topics/GHC_from_source.md), specifies the
 `-j[<n>]` flag of GHC's Hadrian build system.
 
 In some circumstances, the default can cause some machines to run out of memory
diff --git a/doc/topics/GHC_from_source.md b/doc/topics/GHC_from_source.md
@@ -0,0 +1,163 @@
+<div class="hidden-warning"><a href="https://docs.haskellstack.org/"><img src="https://cdn.jsdelivr.net/gh/commercialhaskell/stack/doc/img/hidden-warning.svg"></a></div>
+
+# Building GHC from source
+
+:octicons-beaker-24: Experimental
+
+[:octicons-tag-24: 2.1.1](https://github.com/commercialhaskell/stack/releases/tag/v2.1.1)
+
+Stack supports building the GHC compiler from source, using
+[Hadrian](https://gitlab.haskell.org/ghc/ghc/blob/master/hadrian/README.md) (the
+build system for GHC). The GHC version to build and to use is defined by a a Git
+commit ID and a Hadrian "flavour", with the following syntax in a YAML
+configuration file:
+
+~~~yaml
+compiler: ghc-git-<commit_id>-<Hadrian_flavour>
+~~~
+
+In the following example the commit ID is "5be7ad..." and the flavour is
+"quick":
+
+~~~yaml
+compiler: ghc-git-5be7ad7861c8d39f60b7101fd8d8e816ff50353a-quick
+~~~
+
+By default, the code is retrieved from the main GHC repository. If you want to
+select another repository, use the `compiler-repository` option in a YAML
+configuration file:
+
+~~~yaml
+compiler-repository: git://my/ghc/repository
+# default
+# compiler-repository: https://gitlab.haskell.org/ghc/ghc.git
+~~~
+
+Stack does not check the compiler version when it uses a compiler built from
+source. It is assumed that the built compiler is recent enough as Stack does not
+enable any known workaround to make older compilers work.
+
+Building the compiler can take a very long time (more than one hour). For faster
+build times, use Hadrian flavours that disable documentation generation.
+
+### Bootstrap compiler
+
+Building GHC from source requires a working GHC (known as the bootstrap
+compiler). As we use a Stack based version of Hadrian (`hadrian/build-stack` in
+GHC sources), the bootstrap compiler is configured into `hadrian/stack.yaml` and
+fully managed by Stack.
+
+!!! note
+
+    For some commit IDs, the snapshot specified in `hadrian/stack.yaml`
+    specifies a version of GHC that cannot be used to build GHC. This results in
+    GHC's `configure` script reporting messages similar to the following before
+    aborting:
+
+    ~~~text
+    checking version of ghc... 9.0.2
+    configure: error: GHC version 9.2 or later is required to compile GHC.
+    ~~~
+
+    The resolution is: (1) to specify an alternative snapshot (one that
+    specifies a sufficiently recent version of GHC) on the command line, using
+    Stack's option `--snapshot <snapshot>`. Stack will use that snapshot when
+    running GHC's `configure` script; and (2) to set the contents of the `STACK`
+    environment variable to be `stack --snapshot <snapshot>`. Hadrian's
+    `build-stack` script wil refer to that environment variable for the Stack
+    command it uses.
+
+### Hadrian prerequisites
+
+The Hadrian build system has certain
+[prerequisites](https://gitlab.haskell.org/ghc/ghc/-/wikis/building/preparation).
+It requires certain versions of the `happy` and `alex` executables on the PATH.
+Stack will build and install `happy` and `alex`, if not already on the PATH.
+
+=== "macOS"
+
+    Hadrian requires, or case use, certain tools or Python packages that do not
+    come with macOS by default and that need to be installed using `brew` or
+    `pip3` (Python). Hadrian's LaTeX documentation also requires the
+    [DejaVu fonts](https://dejavu-fonts.github.io/) to be installed.
+
+    ~~~zsh
+    brew install python@3.11
+    # GHC uses a Python script named `boot`.
+    brew install automake
+    # Tool for generating GNU Standards-compliant Makefiles.
+    brew install texinfo
+    # Official documentation format of the GNU project.
+    pip3 install -U sphinx
+    # Sphinx is the Python documentation generator.
+    brew install --cask mactex
+    # MacTeX: Full TeX Live distribution with GUI applications
+    ~~~
+
+=== "Windows"
+
+    Hadrian requires, or can use, certain MSYS2 or Python packages that do not
+    come with the Stack-supplied MSYS2 by default and need to be installed
+    using `pacman` (MSYS2) or `pip` (Python). Hadrian's LaTeX documentation also
+    requires the [DejaVu fonts](https://dejavu-fonts.github.io/) to be
+    installed.
+
+    ~~~pwsh
+    stack exec -- pacman --sync --refresh
+    # Synchronize MSYS2 package databases
+    stack exec -- pacman --sync mingw-w64-x86_64-python-pip
+    # The PyPA recommended tool (pip) for installing Python packages. Also
+    # installs Python as a dependency. GHC uses a Python script named `boot`.
+    # The package must be the one from the `mingw64` MSYS2 repository, as Python
+    # from the `msys` repository cannot interpret Windows file paths correctly.
+    stack exec -- pacman --sync mingw-w64-x86_64-autotools
+    # The GNU autotools build system, including `autoreconf`, `aclocal`
+    # and `make`. GHC uses a sh script named `configure` which is itself created
+    # from a file named `configure.ac`.
+    stack exec -- pacman --sync patch
+    # A utility to apply patch files to original sources.
+    stack exec -- pacman --sync texinfo
+    # Utilities to work with and produce manuals, ASCII text, and on-line
+    # documentation from a single source file, including `makeinfo`.
+    stack exec -- pacman --sync mingw-w64-x86_64-ca-certificates
+    # Common CA (certificate authority) certificates.
+    stack exec -- pip install -U sphinx
+    # Sphinx is the Python documentation generator.
+    ~~~
+
+    Hadrian may require certain LaTeX packages and may prompt for these to be
+    installed duing the build process.
+
+### Global packages
+
+The GHC compiler you build from sources may depend on unreleased versions of
+some global packages (e.g. Cabal). It may be an issue if a package you try to
+build with this compiler depends on such global packages because Stack may not
+be able to find versions of those packages (on Hackage, etc.) that are
+compatible with the compiler.
+
+The easiest way to deal with this issue is to use the
+[`drop-packages`](../configure/yaml/project.md#drop-packages)
+project-specific configuration option to drop the offending packages as follows.
+Instead of using the packages specified in the snapshot, the global packages
+bundled with GHC will be used.
+
+~~~yaml
+drop-packages:
+- Cabal
+- ...
+~~~
+
+Another way to deal with this issue is to add the relevant packages as
+[`extra-deps`](../configure/yaml/project.md#extra-deps) built from source. To
+avoid mismatching versions, you can use exactly the same commit id you used to
+build GHC as follows:
+
+~~~
+extra-deps:
+- git: https://gitlab.haskell.org/ghc/ghc.git
+  commit: '5be7ad7861c8d39f60b7101fd8d8e816ff50353a'
+  subdirs:
+    - libraries/Cabal/Cabal
+    - libraries/...
+~~~
diff --git a/mkdocs.yml b/mkdocs.yml
@@ -114,6 +114,7 @@ nav:
   - Docker integration: topics/docker_integration.md
   - Nix integration: topics/nix_integration.md
   - Non-standard project initialization: topics/nonstandard_project_init.md
+  - Building GHC from source: topics/GHC_from_source.md
   - Debugging: topics/debugging.md
   - Editor integration: topics/editor_integration.md
   - Stack and Visual Studio Code: topics/Stack_and_VS_Code.md
