Library names, with Cabal submodule update

A library name is a package name, package version, and hash of the
version names of all textual dependencies (i.e. packages which were included.) A library
name is a coarse approximation of installed package IDs, which are suitable for
inclusion in package keys (you don't want to put an IPID in a package key, since
it means the key will change any time the source changes.)

    - We define ShPackageKey, which is the semantic object which
      is hashed into a PackageKey.  You can use 'newPackageKey'
      to hash a ShPackageKey to a PackageKey

    - Given a PackageKey, we can lookup its ShPackageKey with
      'lookupPackageKey'.  The way we can do this is by consulting
      the 'pkgKeyCache', which records a reverse mapping from
      every hash to the ShPackageKey.  This means that if you
      load in PackageKeys from external sources (e.g. interface
      files), you also need to load in a mapping of PackageKeys
      to their ShPackageKeys so we can populate the cache.

    - We define a 'LibraryName' which encapsulates the full
      depenency resolution that Cabal may have selected; this
      is opaque to GHC but can be used to distinguish different
      versions of a package.

    - Definite packages don't have an interesting PackageKey,
      so we rely on Cabal to pass them to us.

    - We can pretty-print package keys while displaying the
      instantiation, but it's not wired up to anything (e.g.
      the Outputable instance of PackageKey).

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

Test Plan: validate

Reviewers: austin, bgamari

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D1056

GHC Trac Issues: #10566

1 files changed, 20 insertions, 0 deletions

diff --git a/compiler/main/PackageConfig.hs b/compiler/main/PackageConfig.hs
index 3c41151c11..71a84d8622 100644
--- a/compiler/main/PackageConfig.hs
+++ b/compiler/main/PackageConfig.hs
@@ -12,13 +12,18 @@ module PackageConfig (
         -- * PackageKey
         packageConfigId,
 
+        -- * LibraryName
+        LibraryName(..),
+
         -- * The PackageConfig type: information about a package
         PackageConfig,
         InstalledPackageInfo(..),
         InstalledPackageId(..),
         SourcePackageId(..),
         PackageName(..),
+        UnitName(..),
         Version(..),
+        packageUnitName,
         defaultPackageConfig,
         installedPackageIdString,
         sourcePackageIdString,
@@ -54,6 +59,8 @@ type PackageConfig = InstalledPackageInfo
 newtype InstalledPackageId = InstalledPackageId FastString deriving (Eq, Ord)
 newtype SourcePackageId    = SourcePackageId    FastString deriving (Eq, Ord)
 newtype PackageName        = PackageName        FastString deriving (Eq, Ord)
+newtype UnitName           = UnitName           FastString deriving (Eq, Ord)
+newtype LibraryName        = LibraryName        FastString deriving (Eq, Ord)
 
 instance BinaryStringRep InstalledPackageId where
   fromStringRep = InstalledPackageId . mkFastStringByteString
@@ -67,6 +74,10 @@ instance BinaryStringRep PackageName where
   fromStringRep = PackageName . mkFastStringByteString
   toStringRep (PackageName s) = fastStringToByteString s
 
+instance BinaryStringRep LibraryName where
+  fromStringRep = LibraryName . mkFastStringByteString
+  toStringRep (LibraryName s) = fastStringToByteString s
+
 instance Uniquable InstalledPackageId where
   getUnique (InstalledPackageId n) = getUnique n
 
@@ -79,6 +90,12 @@ instance Uniquable PackageName where
 instance Outputable InstalledPackageId where
   ppr (InstalledPackageId str) = ftext str
 
+instance Outputable UnitName where
+  ppr (UnitName str) = ftext str
+
+instance Outputable LibraryName where
+  ppr (LibraryName str) = ftext str
+
 instance Outputable SourcePackageId where
   ppr (SourcePackageId str) = ftext str
 
@@ -172,3 +189,6 @@ pprPackageConfig InstalledPackageInfo {..} =
 packageConfigId :: PackageConfig -> PackageKey
 packageConfigId = packageKey
 
+packageUnitName :: PackageConfig -> UnitName
+packageUnitName pkg = let PackageName fs = packageName pkg
+                      in UnitName fs