hadrian: Inplace/Final package databases

There are now two different package databases per stage. An inplace
package database contains .conf files which point directly into the
build directories. The final package database contains .conf files which
point into the installed locations. The inplace .conf files are created
before any building happens and have fake ABI hash values. The final
.conf files are created after a package finished building and contains
the proper ABI has.

The motivation for this is to make the dependency structure more
fine-grained when building modules. Now a module depends just depends
directly on M.o from package p rather than the .conf file depend on the
.conf file for package p. So when all of a modules direct dependencies
have finished building we can start building it rather than waiting for
the whole package to finish.

The secondary motivation is that the multi-repl doesn't need to build
everything before starting the multi-repl session. We can just configure
the inplace package-db and use that in order to start the repl.

1 files changed, 4 insertions, 4 deletions

diff --git a/hadrian/src/Settings/Builders/Common.hs b/hadrian/src/Settings/Builders/Common.hs
index a011cb0dae..e89152be9e 100644
--- a/hadrian/src/Settings/Builders/Common.hs
+++ b/hadrian/src/Settings/Builders/Common.hs
@@ -53,15 +53,15 @@ cWarnings = mconcat
 
 packageDatabaseArgs :: Args
 packageDatabaseArgs = do
-    stage <- getStage
-    dbPath <- expr (packageDbPath stage)
+    loc <- getPackageDbLoc
+    dbPath <- expr (packageDbPath loc)
     expr (need [dbPath -/- packageDbStamp])
     prefix <- ifM (builder Ghc) (return "-package-db ") (return "--package-db=")
     arg $ prefix ++ dbPath
 
 bootPackageDatabaseArgs :: Args
 bootPackageDatabaseArgs = do
-    stage  <- getStage
-    dbPath <- expr $ packageDbPath stage
+    loc <- getPackageDbLoc
+    dbPath <- expr $ packageDbPath loc
     expr $ need [dbPath -/- packageDbStamp]
     stage0 ? packageDatabaseArgs