Hadrian: make settings, platformConstants, etc dependencies of lib:ghc

This fixes #17003, where a user directly asked for the 'docs-haddock' target
without building a complete stage 2 GHC first. Since haddock only depends on
lib:ghc, the stage 2 GHC executable wasn't built, and neither were the
settings, platformConstants, llvm-passes and llvm-targets files, since they
are declared to be dependencies of exe:ghc.

This makes sense in general since all GHC API users (haddock is one) will likely
want those files to be there.

4 files changed, 19 insertions, 18 deletions

diff --git a/hadrian/src/Base.hs b/hadrian/src/Base.hs
index 19573de8fd..bc4eab354e 100644
--- a/hadrian/src/Base.hs
+++ b/hadrian/src/Base.hs
@@ -24,8 +24,8 @@ module Base (
     -- * Paths
     hadrianPath, configPath, configFile, sourcePath, shakeFilesDir,
     generatedDir, generatedPath, stageBinPath, stageLibPath, templateHscPath,
-    ghcDeps, includesDependencies, haddockDeps, relativePackageDbPath,
-    packageDbPath, packageDbStamp, mingwStamp,
+    ghcBinDeps, ghcLibDeps, includesDependencies, haddockDeps,
+    relativePackageDbPath, packageDbPath, packageDbStamp, mingwStamp,
     ) where
 
 import Control.Applicative
@@ -106,15 +106,21 @@ stageBinPath stage = buildRoot <&> (-/- stageString stage -/- "bin")
 stageLibPath :: Stage -> Action FilePath
 stageLibPath stage = buildRoot <&> (-/- stageString stage -/- "lib")
 
+-- | Files the GHC library depends on
+ghcLibDeps :: Stage -> Action [FilePath]
+ghcLibDeps stage = mapM (\f -> stageLibPath stage <&> (-/- f))
+    [ "llvm-targets"
+    , "llvm-passes"
+    , "platformConstants"
+    , "settings"
+    ]
+
 -- | Files the GHC binary depends on.
-ghcDeps :: Stage -> Action [FilePath]
-ghcDeps stage = mapM (\f -> stageLibPath stage <&> (-/- f))
+ghcBinDeps :: Stage -> Action [FilePath]
+ghcBinDeps stage = mapM (\f -> stageLibPath stage <&> (-/- f))
     [ "ghc-usage.txt"
     , "ghci-usage.txt"
-    , "llvm-targets"
-    , "llvm-passes"
-    , "platformConstants"
-    , "settings" ]
+    ]
 
 includesDependencies :: Action [FilePath]
 includesDependencies = do
diff --git a/hadrian/src/Builder.hs b/hadrian/src/Builder.hs
index 581161f984..892f89772d 100644
--- a/hadrian/src/Builder.hs
+++ b/hadrian/src/Builder.hs
@@ -184,7 +184,7 @@ instance H.Builder Builder where
 
             -- GHC from the previous stage is used to build artifacts in the
             -- current stage. Need the previous stage's GHC deps.
-            ghcdeps <- ghcDeps (pred stage)
+            ghcdeps <- ghcBinDeps (pred stage)
 
             return $ [ unlitPath ]
                   ++ ghcdeps
diff --git a/hadrian/src/Rules/Program.hs b/hadrian/src/Rules/Program.hs
index 96855a3927..b5dde25624 100644
--- a/hadrian/src/Rules/Program.hs
+++ b/hadrian/src/Rules/Program.hs
@@ -83,10 +83,7 @@ buildProgram bin ctx@(Context{..}) rs = do
     template <- templateHscPath stage
     need [template]
   when (package == ghc) $ do
-    -- GHC depends on @settings@, @platformConstants@,
-    -- @llvm-targets@, @ghc-usage.txt@, @ghci-usage.txt@,
-    -- @llvm-passes@.
-    need =<< ghcDeps stage
+    need =<< ghcBinDeps stage
   when (package == haddock) $ do
     -- Haddock has a resource folder
     need =<< haddockDeps stage
diff --git a/hadrian/src/Rules/Register.hs b/hadrian/src/Rules/Register.hs
index 4275ab1fa2..e9451c2648 100644
--- a/hadrian/src/Rules/Register.hs
+++ b/hadrian/src/Rules/Register.hs
@@ -90,14 +90,12 @@ registerPackageRules rs stage = do
     -- Register a package.
     root -/- relativePackageDbPath stage -/- "*.conf" %> \conf -> do
         historyDisable
-        let libpath = takeDirectory (takeDirectory conf)
-            settings = libpath -/- "settings"
-            platformConstants = libpath -/- "platformConstants"
-
-        need [settings, platformConstants]
 
         pkgName <- getPackageNameFromConfFile conf
         let pkg = unsafeFindPackageByName pkgName
+
+        when (pkg == compiler) $ need =<< ghcLibDeps stage
+
         isBoot <- (pkg `notElem`) <$> stagePackages Stage0
 
         let ctx = Context stage pkg vanilla