Clean up opt and llc

The LLVM backend shells out to LLVMs `opt` and `llc` tools. This clean
up introduces a shared data structure to carry the arguments we pass to
each tool so that corresponding flags are next to each other. It drops
the hard coded data layouts in favor of using `-mtriple` and have LLVM
infer them. Furthermore we add `clang` as a proper tool, so we don't
rely on assuming that `clang` is called `clang` on the `PATH` when using
`clang` as the assembler.  Finally this diff also changes the type of
`optLevel` from `Int` to `Word`, as we do not have negative optimization
levels.

Reviewers: erikd, hvr, austin, rwbarton, bgamari, kavon

Reviewed By: kavon

Subscribers: michalt, Ericson2314, ryantrinkle, dfeuer, carter, simonpj,
kavon, simonmar, thomie, erikd, snowleopard

Differential Revision: https://phabricator.haskell.org/D3352

1 files changed, 19 insertions, 2 deletions

diff --git a/compiler/main/SysTools.hs b/compiler/main/SysTools.hs
index b48bbf4202..cd7a23d833 100644
--- a/compiler/main/SysTools.hs
+++ b/compiler/main/SysTools.hs
@@ -13,6 +13,7 @@
 module SysTools (
         -- Initialisation
         initSysTools,
+        initLlvmTargets,
 
         -- Interface to system tools
         runUnlit, runCpp, runCc, -- [Option] -> IO ()
@@ -174,6 +175,20 @@ stuff.
 ************************************************************************
 -}
 
+initLlvmTargets :: Maybe String
+                -> IO LlvmTargets
+initLlvmTargets mbMinusB
+  = do top_dir <- findTopDir mbMinusB
+       let llvmTargetsFile = top_dir </> "llvm-targets"
+       llvmTargetsStr <- readFile llvmTargetsFile
+       case maybeReadFuzzy llvmTargetsStr of
+         Just s -> return (fmap mkLlvmTarget <$> s)
+         Nothing -> pgmError ("Can't parse " ++ show llvmTargetsFile)
+  where
+    mkLlvmTarget :: (String, String, String) -> LlvmTarget
+    mkLlvmTarget (dl, cpu, attrs) = LlvmTarget dl cpu (words attrs)
+
+
 initSysTools :: Maybe String    -- Maybe TopDir path (without the '-B' prefix)
              -> IO Settings     -- Set all the mutable variables above, holding
                                 --      (a) the system programs
@@ -309,6 +324,7 @@ initSysTools mbMinusB
        -- We just assume on command line
        lc_prog <- getSetting "LLVM llc command"
        lo_prog <- getSetting "LLVM opt command"
+       lcc_prog <- getSetting "LLVM clang command"
 
        let iserv_prog = libexec "ghc-iserv"
 
@@ -352,6 +368,7 @@ initSysTools mbMinusB
                     sPgm_libtool = libtool_path,
                     sPgm_lo  = (lo_prog,[]),
                     sPgm_lc  = (lc_prog,[]),
+                    sPgm_lcc = (lcc_prog,[]),
                     sPgm_i   = iserv_prog,
                     sOpt_L       = [],
                     sOpt_P       = [],
@@ -360,6 +377,7 @@ initSysTools mbMinusB
                     sOpt_a       = [],
                     sOpt_l       = [],
                     sOpt_windres = [],
+                    sOpt_lcc     = [],
                     sOpt_lo      = [],
                     sOpt_lc      = [],
                     sOpt_i       = [],
@@ -574,8 +592,7 @@ runLlvmLlc dflags args = do
 -- assembler)
 runClang :: DynFlags -> [Option] -> IO ()
 runClang dflags args = do
-  -- we simply assume its available on the PATH
-  let clang = "clang"
+  let (clang,_) = pgm_lcc dflags
       -- be careful what options we call clang with
       -- see #5903 and #7617 for bugs caused by this.
       (_,args0) = pgm_a dflags