Hadrian: merge sections in profiling _p.a to .p_o for ghci

This is the hadrain version of {D5169}

* We build squashed .o and .p_o for ghci when `dynamicGhcPrograms` is
`False`
* We no longer build them for rts as ghci never loads it

we need https://github.com/haskell/cabal/pull/5592 for cabal to copy
the built `.p_o` file.

Test Plan:
```
$ grep dynamicGhc hadrian/UserSettings.hs
  , dynamicGhcPrograms = return False
$ touch ...
$ hadrian/build.sh --flavour=user -j --digest-or
$ find _build/stage1/libraries/ -name 'HS*-*.*o' | wc
     62      62    3664
```

```
$ grep -C3 dynamicGhc hadrian/UserSettings.hs
userFlavour :: Flavour
userFlavour = performanceFlavour
  { name = "user"
  , dynamicGhcPrograms = return False
  }
$ hadrian/build.sh -j --flavour=user test --verbose
Unexpected results from:
TEST="T3807 T9208 T9293 annth_make ghci057 haddock.Cabal haddock.base
haddock.compiler"

SUMMARY for test run started at Wed Dec  5 17:45:39 2018 PST
 0:03:16 spent to go through
    6708 total tests, which gave rise to
   26015 test cases, of which
   19290 were skipped

      29 had missing libraries
    6600 expected passes
      88 expected failures

       3 caused framework failures
       0 caused framework warnings
       1 unexpected passes
       7 unexpected failures
       0 unexpected stat failures
$ find _build -name 'HSbase*.*o'
_build/stage1/lib/x86_64-linux-ghc-8.7.20181204/base-4.12.0.0/HSbase-4.1
2.0.0.o
_build/stage1/lib/x86_64-linux-ghc-8.7.20181204/base-4.12.0.0/HSbase-4.1
2.0.0.p_o
_build/stage1/libraries/base/build/HSbase-4.12.0.0.o
_build/stage1/libraries/base/build/HSbase-4.12.0.0.p_o
```

Reviewers: bgamari, simonmar, snowleopard

Reviewed By: snowleopard

Subscribers: alpmestan, rwbarton, carter

GHC Trac Issues: #15779

Differential Revision: https://phabricator.haskell.org/D5270

4 files changed, 22 insertions, 12 deletions

diff --git a/hadrian/src/Context.hs b/hadrian/src/Context.hs
index 745901159d..672b3a6004 100644
--- a/hadrian/src/Context.hs
+++ b/hadrian/src/Context.hs
@@ -96,7 +96,9 @@ pkgLibraryFile context@Context {..} = do
 -- | Path to the GHCi library file of a given 'Context', e.g.:
 -- @_build/stage1/libraries/array/build/HSarray-0.5.1.0.o@.
 pkgGhciLibraryFile :: Context -> Action FilePath
-pkgGhciLibraryFile context = pkgFile context "HS" ".o"
+pkgGhciLibraryFile context@Context {..} = do
+    let extension = "" <.> osuf way
+    pkgFile context "HS" extension
 
 -- | Path to the configuration file of a given 'Context'.
 pkgConfFile :: Context -> Action FilePath
diff --git a/hadrian/src/Rules/Library.hs b/hadrian/src/Rules/Library.hs
index 24a94241c6..122004084a 100644
--- a/hadrian/src/Rules/Library.hs
+++ b/hadrian/src/Rules/Library.hs
@@ -25,7 +25,9 @@ libraryRules = do
     root -/- "//libHS*-*.dylib"       %> buildDynamicLibUnix root "dylib"
     root -/- "//libHS*-*.so"          %> buildDynamicLibUnix root "so"
     root -/- "//*.a"                  %> buildStaticLib      root
-    priority 2 $ root -/- "//HS*-*.o" %> buildGhciLibO       root
+    priority 2 $ do
+        root -/- "//HS*-*.o" %> buildGhciLibO root
+        root -/- "//HS*-*.p_o" %> buildGhciLibO root
 
 -- * 'Action's for building libraries
 
@@ -193,8 +195,9 @@ parseLibGhciFilename :: Parsec.Parsec String () LibGhci
 parseLibGhciFilename = do
     _ <- Parsec.string "HS"
     (pkgname, pkgver) <- parsePkgId
-    way <- parseWaySuffix vanilla
-    _ <- Parsec.string ".o"
+    _ <- Parsec.string "."
+    way <- parseWayPrefix vanilla
+    _ <- Parsec.string "o"
     return (LibGhci pkgname pkgver way)
 
 -- | Parse the filename of a dynamic library to be built into a 'LibDyn' value.
diff --git a/hadrian/src/Settings/Builders/Cabal.hs b/hadrian/src/Settings/Builders/Cabal.hs
index f33e9b458c..80b9b67a71 100644
--- a/hadrian/src/Settings/Builders/Cabal.hs
+++ b/hadrian/src/Settings/Builders/Cabal.hs
@@ -57,19 +57,24 @@ libraryArgs :: Args
 libraryArgs = do
     flavourWays <- getLibraryWays
     contextWay  <- getWay
+    package     <- getPackage
     withGhci    <- expr ghcWithInterpreter
     dynPrograms <- expr (flavour >>= dynamicGhcPrograms)
     let ways = flavourWays ++ [contextWay]
-    pure [ if vanilla `elem` ways
+        hasVanilla = vanilla `elem` ways
+        hasProfiling = any (wayUnit Profiling) ways
+        hasDynamic = any (wayUnit Dynamic) ways
+    pure [ if hasVanilla
            then  "--enable-library-vanilla"
            else "--disable-library-vanilla"
-         , if vanilla `elem` ways && withGhci && not dynPrograms
-           then  "--enable-library-for-ghci"
-           else "--disable-library-for-ghci"
-         , if or [Profiling `wayUnit` way | way <- ways]
+         , if hasProfiling
            then  "--enable-library-profiling"
            else "--disable-library-profiling"
-         , if or [Dynamic `wayUnit` way | way <- ways]
+         , if (hasVanilla || hasProfiling) &&
+              package /= rts && withGhci && not dynPrograms
+           then  "--enable-library-for-ghci"
+           else "--disable-library-for-ghci"
+         , if hasDynamic
            then  "--enable-shared"
            else "--disable-shared" ]
 
diff --git a/hadrian/src/Utilities.hs b/hadrian/src/Utilities.hs
index 7fe6a89dae..d31f6cc2d0 100644
--- a/hadrian/src/Utilities.hs
+++ b/hadrian/src/Utilities.hs
@@ -61,10 +61,10 @@ stage1Dependencies =
 -- | Given a library 'Package' this action computes all of its targets. See
 -- 'packageTargets' for the explanation of the @includeGhciLib@ parameter.
 libraryTargets :: Bool -> Context -> Action [FilePath]
-libraryTargets includeGhciLib context = do
+libraryTargets includeGhciLib context@Context {..} = do
     libFile  <- pkgLibraryFile     context
     ghciLib  <- pkgGhciLibraryFile context
-    ghci     <- if includeGhciLib
+    ghci     <- if includeGhciLib && not (wayUnit Dynamic way)
                 then interpretInContext context $ getContextData buildGhciLib
                 else return False
     return $ [ libFile ] ++ [ ghciLib | ghci ]