Package keys (for linking/type equality) separated from package IDs.

This patch set makes us no longer assume that a package key is a human
readable string, leaving Cabal free to "do whatever it wants" to allocate
keys; we'll look up the PackageId in the database to display to the user.
This also means we have a new level of qualifier decisions to make at the
package level, and rewriting some Safe Haskell error reporting code to DTRT.

Additionally, we adjust the build system to use a new ghc-cabal output
Make variable PACKAGE_KEY to determine library names and other things,
rather than concatenating PACKAGE/VERSION as before.

Adds a new `-this-package-key` flag to subsume the old, erroneously named
`-package-name` flag, and `-package-key` to select packages by package key.

RFC: The md5 hashes are pretty tough on the eye, as far as the file
system is concerned :(

ToDo: safePkg01 test had its output updated, but the fix is not really right:
the rest of the dependencies are truncated due to the fact the we're only
grepping a single line, but ghc-pkg is wrapping its output.

ToDo: In a later commit, update all submodules to stop using -package-name
and use -this-package-key.  For now, we don't do it to avoid submodule
explosion.

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

Test Plan: validate

Reviewers: simonpj, simonmar, hvr, austin

Subscribers: simonmar, relrod, carter

Differential Revision: https://phabricator.haskell.org/D80

7 files changed, 20 insertions, 9 deletions

diff --git a/libraries/Cabal b/libraries/Cabal
-Subproject 96847693bf8ff48ae94f179d60c1f23411e1365
+Subproject 6cc46998f0778c04b535c805416604995fe153b
diff --git a/libraries/base/base.cabal b/libraries/base/base.cabal
index e56724ce4f..b7828a9c20 100644
--- a/libraries/base/base.cabal
+++ b/libraries/base/base.cabal
@@ -328,6 +328,6 @@ Library
             GHC.Event.TimerManager
             GHC.Event.Unique
 
-    -- We need to set the package name to base (without a version number)
+    -- We need to set the package key to base (without a version number)
     -- as it's magic.
-    ghc-options: -package-name base
+    ghc-options: -this-package-key base
diff --git a/libraries/bin-package-db/Distribution/InstalledPackageInfo/Binary.hs b/libraries/bin-package-db/Distribution/InstalledPackageInfo/Binary.hs
index f4d0a4b147..baf8a05159 100644
--- a/libraries/bin-package-db/Distribution/InstalledPackageInfo/Binary.hs
+++ b/libraries/bin-package-db/Distribution/InstalledPackageInfo/Binary.hs
@@ -49,6 +49,7 @@ putInstalledPackageInfo :: Binary m => InstalledPackageInfo_ m -> Put
 putInstalledPackageInfo ipi = do
   put (sourcePackageId ipi)
   put (installedPackageId ipi)
+  put (packageKey ipi)
   put (license ipi)
   put (copyright ipi)
   put (maintainer ipi)
@@ -84,6 +85,7 @@ getInstalledPackageInfo :: Binary m => Get (InstalledPackageInfo_ m)
 getInstalledPackageInfo = do
   sourcePackageId <- get
   installedPackageId <- get
+  packageKey <- get
   license <- get
   copyright <- get
   maintainer <- get
@@ -166,3 +168,12 @@ instance Binary m => Binary (ModuleExport m) where
   put (ModuleExport a b c d) = do put a; put b; put c; put d
   get = do a <- get; b <- get; c <- get; d <- get;
            return (ModuleExport a b c d)
+
+instance Binary PackageKey where
+  put (PackageKey a b c) = do putWord8 0; put a; put b; put c
+  put (OldPackageKey a) = do putWord8 1; put a
+  get = do n <- getWord8
+           case n of
+            0 -> do a <- get; b <- get; c <- get; return (PackageKey a b c)
+            1 -> do a <- get; return (OldPackageKey a)
+            _ -> error ("Binary PackageKey: bad branch " ++ show n)
diff --git a/libraries/ghc-prim/ghc-prim.cabal b/libraries/ghc-prim/ghc-prim.cabal
index bc9f57126a..9c1801b4d6 100644
--- a/libraries/ghc-prim/ghc-prim.cabal
+++ b/libraries/ghc-prim/ghc-prim.cabal
@@ -59,6 +59,6 @@ Library
         cbits/popcnt.c
         cbits/word2float.c
 
-    -- We need to set the package name to ghc-prim (without a version number)
+    -- We need to set the package key to ghc-prim (without a version number)
     -- as it's magic.
-    ghc-options: -package-name ghc-prim
+    ghc-options: -this-package-key ghc-prim
diff --git a/libraries/integer-gmp/integer-gmp.cabal b/libraries/integer-gmp/integer-gmp.cabal
index c0f6b60aa4..376139f102 100644
--- a/libraries/integer-gmp/integer-gmp.cabal
+++ b/libraries/integer-gmp/integer-gmp.cabal
@@ -75,6 +75,6 @@ Library
 
     build-depends: ghc-prim >= 0.3.1 && < 0.4
 
-    -- We need to set the package name to integer-gmp
+    -- We need to set the package key to integer-gmp
     -- (without a version number) as it's magic.
-    ghc-options: -Wall -package-name integer-gmp
+    ghc-options: -Wall -this-package-key integer-gmp
diff --git a/libraries/integer-simple/integer-simple.cabal b/libraries/integer-simple/integer-simple.cabal
index 51d3cc7b5b..d18a182012 100644
--- a/libraries/integer-simple/integer-simple.cabal
+++ b/libraries/integer-simple/integer-simple.cabal
@@ -28,4 +28,4 @@ Library
                 UnliftedFFITypes, NoImplicitPrelude
     -- We need to set the package name to integer-simple
     -- (without a version number) as it's magic.
-    ghc-options: -package-name integer-simple -Wall
+    ghc-options: -this-package-key integer-simple -Wall
diff --git a/libraries/template-haskell/template-haskell.cabal b/libraries/template-haskell/template-haskell.cabal
index fb8dbd7ab0..db268be212 100644
--- a/libraries/template-haskell/template-haskell.cabal
+++ b/libraries/template-haskell/template-haskell.cabal
@@ -49,6 +49,6 @@ Library
         base       == 4.7.*,
         pretty     == 1.1.*
 
-    -- We need to set the package name to template-haskell (without a
+    -- We need to set the package key to template-haskell (without a
     -- version number) as it's magic.
-    ghc-options: -Wall -package-name template-haskell
+    ghc-options: -Wall -this-package-key template-haskell