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

3 files changed, 8 insertions, 8 deletions

diff --git a/compiler/deSugar/Coverage.lhs b/compiler/deSugar/Coverage.lhs
index e646667651..fae5f36426 100644
--- a/compiler/deSugar/Coverage.lhs
+++ b/compiler/deSugar/Coverage.lhs
@@ -154,8 +154,8 @@ writeMixEntries dflags mod count entries filename
             mod_name = moduleNameString (moduleName mod)
 
             hpc_mod_dir
-              | modulePackageId mod == mainPackageId  = hpc_dir
-              | otherwise = hpc_dir ++ "/" ++ packageIdString (modulePackageId mod)
+              | modulePackageKey mod == mainPackageKey  = hpc_dir
+              | otherwise = hpc_dir ++ "/" ++ packageKeyString (modulePackageKey mod)
 
             tabStop = 8 -- <tab> counts as a normal char in GHC's location ranges.
 
@@ -1233,9 +1233,9 @@ hpcInitCode this_mod (HpcInfo tickCount hashNo)
     module_name  = hcat (map (text.charToC) $
                          bytesFS (moduleNameFS (Module.moduleName this_mod)))
     package_name = hcat (map (text.charToC) $
-                         bytesFS (packageIdFS  (modulePackageId this_mod)))
+                         bytesFS (packageKeyFS  (modulePackageKey this_mod)))
     full_name_str
-       | modulePackageId this_mod == mainPackageId
+       | modulePackageKey this_mod == mainPackageKey
        = module_name
        | otherwise
        = package_name <> char '/' <> module_name
diff --git a/compiler/deSugar/DsForeign.lhs b/compiler/deSugar/DsForeign.lhs
index 0654ebc983..c60e9146bc 100644
--- a/compiler/deSugar/DsForeign.lhs
+++ b/compiler/deSugar/DsForeign.lhs
@@ -224,9 +224,9 @@ dsFCall fn_id co fcall mDeclHeader = do
     dflags <- getDynFlags
     (fcall', cDoc) <-
               case fcall of
-              CCall (CCallSpec (StaticTarget cName mPackageId isFun) CApiConv safety) ->
+              CCall (CCallSpec (StaticTarget cName mPackageKey isFun) CApiConv safety) ->
                do wrapperName <- mkWrapperName "ghc_wrapper" (unpackFS cName)
-                  let fcall' = CCall (CCallSpec (StaticTarget wrapperName mPackageId True) CApiConv safety)
+                  let fcall' = CCall (CCallSpec (StaticTarget wrapperName mPackageKey True) CApiConv safety)
                       c = includes
                        $$ fun_proto <+> braces (cRet <> semi)
                       includes = vcat [ text "#include <" <> ftext h <> text ">"
diff --git a/compiler/deSugar/DsMeta.hs b/compiler/deSugar/DsMeta.hs
index adfc0f688f..2713f95ab6 100644
--- a/compiler/deSugar/DsMeta.hs
+++ b/compiler/deSugar/DsMeta.hs
@@ -1416,7 +1416,7 @@ globalVar name
   where
       mod = ASSERT( isExternalName name) nameModule name
       name_mod = moduleNameString (moduleName mod)
-      name_pkg = packageIdString (modulePackageId mod)
+      name_pkg = packageKeyString (modulePackageKey mod)
       name_occ = nameOccName name
       mk_varg | OccName.isDataOcc name_occ = mkNameG_dName
               | OccName.isVarOcc  name_occ = mkNameG_vName
@@ -2117,7 +2117,7 @@ thLib = mkTHModule (fsLit "Language.Haskell.TH.Lib")
 qqLib = mkTHModule (fsLit "Language.Haskell.TH.Quote")
 
 mkTHModule :: FastString -> Module
-mkTHModule m = mkModule thPackageId (mkModuleNameFS m)
+mkTHModule m = mkModule thPackageKey (mkModuleNameFS m)
 
 libFun, libTc, thFun, thTc, thCon, qqFun :: FastString -> Unique -> Name
 libFun = mk_known_key_name OccName.varName  thLib