Make GHCi & TH work when the compiler is built with -prof

Summary:
Amazingly, there were zero changes to the byte code generator and very
few changes to the interpreter - mainly because we've used good
abstractions that hide the differences between profiling and
non-profiling.  So that bit was pleasantly straightforward, but there
were a pile of other wibbles to get the whole test suite through.

Note that a compiler built with -prof is now like one built with
-dynamic, in that to use TH you have to build the code the same way.
For dynamic, we automatically enable -dynamic-too when TH is required,
but we don't have anything equivalent for profiling, so you have to
explicitly use -prof when building code that uses TH with a profiled
compiler.  For this reason Cabal won't work with TH.  We don't expect
to ship a profiled compiler, so I think that's OK.

Test Plan: validate with GhcProfiled=YES in validate.mk

Reviewers: goldfire, bgamari, rwbarton, austin, hvr, erikd, ezyang

Reviewed By: ezyang

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D1407

GHC Trac Issues: #4837, #545

1 files changed, 0 insertions, 10 deletions

diff --git a/ghc/InteractiveUI.hs b/ghc/InteractiveUI.hs
index 1153afa414..21eff8ff62 100644
--- a/ghc/InteractiveUI.hs
+++ b/ghc/InteractiveUI.hs
@@ -83,7 +83,6 @@ import Data.Maybe
 
 import Exception hiding (catch)
 
-import Foreign.C
 #if __GLASGOW_HASKELL__ >= 709
 import Foreign
 #else
@@ -346,8 +345,6 @@ findEditor = do
         return ""
 #endif
 
-foreign import ccall unsafe "rts_isProfiled" isProfiled :: IO CInt
-
 default_progname, default_prompt, default_prompt2, default_stop :: String
 default_progname = "<interactive>"
 default_prompt = "%s> "
@@ -360,13 +357,6 @@ default_args = []
 interactiveUI :: GhciSettings -> [(FilePath, Maybe Phase)] -> Maybe [String]
               -> Ghc ()
 interactiveUI config srcs maybe_exprs = do
-   -- although GHCi compiles with -prof, it is not usable: the byte-code
-   -- compiler and interpreter don't work with profiling.  So we check for
-   -- this up front and emit a helpful error message (#2197)
-   i <- liftIO $ isProfiled
-   when (i /= 0) $
-     throwGhcException (InstallationError "GHCi cannot be used when compiled with -prof")
-
    -- HACK! If we happen to get into an infinite loop (eg the user
    -- types 'let x=x in x' at the prompt), then the thread will block
    -- on a blackhole, and become unreachable during GC.  The GC will