Rename PackageId to PackageKey, distinguishing it from Cabal's PackageId.

Summary:
Previously, both Cabal and GHC defined the type PackageId, and we expected
them to be roughly equivalent (but represented differently).  This refactoring
separates these two notions.

A package ID is a user-visible identifier; it's the thing you write in a
Cabal file, e.g. containers-0.9.  The components of this ID are semantically
meaningful, and decompose into a package name and a package vrsion.

A package key is an opaque identifier used by GHC to generate linking symbols.
Presently, it just consists of a package name and a package version, but
pursuant to #9265 we are planning to extend it to record other information.
Within a single executable, it uniquely identifies a package.  It is *not* an
InstalledPackageId, as the choice of a package key affects the ABI of a package
(whereas an InstalledPackageId is computed after compilation.)  Cabal computes
a package key for the package and passes it to GHC using -package-name (now
*extremely* misnamed).

As an added bonus, we don't have to worry about shadowing anymore.

As a follow on, we should introduce -current-package-key having the same role as
-package-name, and deprecate the old flag.  This commit is just renaming.

The haddock submodule needed to be updated.

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/D79

Conflicts:
	compiler/main/HscTypes.lhs
	compiler/main/Packages.lhs
	utils/haddock

1 files changed, 3 insertions, 3 deletions

diff --git a/compiler/main/SysTools.lhs b/compiler/main/SysTools.lhs
index 641b0cb12f..3b25c91256 100644
--- a/compiler/main/SysTools.lhs
+++ b/compiler/main/SysTools.lhs
@@ -1316,7 +1316,7 @@ linesPlatform xs =
 
 #endif
 
-linkDynLib :: DynFlags -> [String] -> [PackageId] -> IO ()
+linkDynLib :: DynFlags -> [String] -> [PackageKey] -> IO ()
 linkDynLib dflags0 o_files dep_packages
  = do
     let -- This is a rather ugly hack to fix dynamically linked
@@ -1362,7 +1362,7 @@ linkDynLib dflags0 o_files dep_packages
                       OSMinGW32 ->
                           pkgs
                       _ ->
-                          filter ((/= rtsPackageId) . packageConfigId) pkgs
+                          filter ((/= rtsPackageKey) . packageConfigId) pkgs
     let pkg_link_opts = let (package_hs_libs, extra_libs, other_flags) = collectLinkOpts dflags pkgs_no_rts
                         in  package_hs_libs ++ extra_libs ++ other_flags
 
@@ -1464,7 +1464,7 @@ linkDynLib dflags0 o_files dep_packages
             -------------------------------------------------------------------
 
             let output_fn = case o_file of { Just s -> s; Nothing -> "a.out"; }
-            let buildingRts = thisPackage dflags == rtsPackageId
+            let buildingRts = thisPackage dflags == rtsPackageKey
             let bsymbolicFlag = if buildingRts
                                 then -- -Bsymbolic breaks the way we implement
                                      -- hooks in the RTS