Fix #6820 Update building GHC from source

Author: mpilgrem

ChangeLog.md

@@ -19,6 +19,9 @@ Behavior changes:
   `ls dependencies` command, so that the nodes of
   `stack dot --external --depth 0` are the same as the packages listed by
   `stack ls dependencies --depth 0`.
+* When building GHC from source, on Windows, the default Hadrian build target is
+  `reloc-binary-dist` and the default path to the GHC built by Hadrian is
+  `_build/reloc-bindist`.
 
 Other enhancements:
 
@@ -33,6 +36,10 @@ Other enhancements:
   specified).
 * Add option `-w` as synonym for `--stack-yaml`.
 * `stack new` now allows `codeberg:` as a service for template downloads
+* In YAML configuration files, the `compiler-target` and
+  `compiler-bindist-path` keys are introduced to allow, when building GHC from
+  source, the Hadrian build target and Hadrian path to the built GHC to be
+  specified.
 
 Bug fixes:
 

doc/topics/GHC_from_source.md

@@ -8,7 +8,7 @@
 
 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
+build system for GHC). The GHC version to build and to use is defined by a Git
 commit ID and a Hadrian "flavour", with the following syntax in a YAML
 configuration file:
 
@@ -23,6 +23,10 @@ In the following example the commit ID is "5be7ad..." and the flavour is
 compiler: ghc-git-5be7ad7861c8d39f60b7101fd8d8e816ff50353a-quick
 ~~~
 
+The [`-j`, `--jobs` option](../configure/global_flags.md#-jobs-or-j-option) at
+the command line or the [`jobs`](../configure/yaml/non-project.md#jobs) option
+in a YAML configuraton file can be used to specify Hadrian's `-j[<n>]` flag.
+
 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:
@@ -33,6 +37,40 @@ compiler-repository: git://my/ghc/repository
 # compiler-repository: https://gitlab.haskell.org/ghc/ghc.git
 ~~~
 
+By default, the Hadrian build target is `reloc-binary-dist` on Windows and
+`binary-dist` on other operating systems. If you want to specify another
+Hadrian build target, use the `compiler-target` option in a YAML configuration
+file:
+
+~~~yaml
+compiler-target: binary-dist
+# default (Windows)
+# compiler-target: reloc-binary-dist
+# default (non-Windows)
+# compiler-target: binary-dist
+~~~
+
+By default, Stack assumes that the path to the binary distribution built by
+Hadrian is `_build/reloc-bindist` on Windows and `_build/bindist` on other
+operating systems. If you want to specify another path, use the
+`compiler-bindist-path` option in a YAML configuration file:
+
+~~~yaml
+compiler-bindist-path: _build/bindist
+# default (Windows)
+# compiler-bindist-path: _build/reloc-bindist
+# default (non-Windows)
+# compiler-bindist-path: _build/bindist
+~~~
+
+!!! note
+
+    The Hadrian build target `reloc-binary-dist` was introduced with Git commit
+    id
+    [`fe23629b147d419053052e6e881f6e8ddfbf3bae`](https://gitlab.haskell.org/ghc/ghc/-/commit/fe23629b147d419053052e6e881f6e8ddfbf3bae).
+
+    Once introduced, the target must be used on Windows.
+
 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.
@@ -59,13 +97,17 @@ fully managed by Stack.
     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.
+    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>`. If `<snapshot>` is a path to a local YAML
+        file, it needs to be an absolute one. Hadrian's `build-stack` script
+        will refer to that environment variable for the Stack command it uses.
 
 ### Hadrian prerequisites
 
@@ -121,8 +163,10 @@ Stack will build and install `happy` and `alex`, if not already on the PATH.
     # 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
+    stack exec -- pacman -sync mingw-w64-x86_64-python-sphinx
     # Sphinx is the Python documentation generator.
+    stack exec -- pacman -sync mingw-w64-x86_64-texlive-full
+    # The TeX Live distribution.
     ~~~
 
     Hadrian may require certain LaTeX packages and may prompt for these to be

src/Stack/Config.hs

@@ -113,7 +113,10 @@ import           Stack.Types.Build.Exception
 import           Stack.Types.BuildConfig ( BuildConfig (..) )
 import           Stack.Types.BuildOpts ( BuildOpts (..) )
 import           Stack.Types.ColorWhen ( ColorWhen (..) )
-import           Stack.Types.Compiler ( defaultCompilerRepository )
+import           Stack.Types.Compiler
+                   ( defaultCompilerBindistPath, defaultCompilerRepository
+                   , defaultCompilerTarget
+                   )
 import           Stack.Types.Config
                    ( Config (..), HasConfig (..), askLatestSnapshotUrl
                    , configProjectRoot, stackRootL, workDirL
@@ -286,6 +289,12 @@ configFromConfigMonoid
         compilerRepository = fromFirst
           defaultCompilerRepository
           configMonoid.compilerRepository
+        compilerTarget = fromFirst
+          defaultCompilerTarget
+          configMonoid.compilerTarget
+        compilerBindistPath = fromFirst
+          defaultCompilerBindistPath
+          configMonoid.compilerBindistPath
         ghcBuild = getFirst configMonoid.ghcBuild
         installGHC = fromFirstTrue configMonoid.installGHC
         installMsys = fromFirst installGHC configMonoid.installMsys
@@ -595,6 +604,8 @@ configFromConfigMonoid
                 , msysEnvironment
                 , compilerCheck
                 , compilerRepository
+                , compilerTarget
+                , compilerBindistPath
                 , localBin
                 , fileWatchHook
                 , requireStackVersion