[commit: ghc] master: LLVM backend: Show expected LLVM version in warnings/errors (0e9a331)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/0e9a331f25c89c6150a43d7d5d27ef5cb6e057ec/ghc

>---------------------------------------------------------------

commit 0e9a331f25c89c6150a43d7d5d27ef5cb6e057ec
Author: Ömer Sinan Ağacan <omeragacan at gmail.com>
Date:   Fri Dec 18 12:21:47 2015 -0500

    LLVM backend: Show expected LLVM version in warnings/errors
    
    Summary:
    Before:
    
        [1 of 1] Compiling Main             ( Main.hs, Main.o )
        You are using a new version of LLVM that hasn't been tested yet!
        We will try though...
    
    After:
    
        [1 of 1] Compiling Main             ( Main.hs, Main.o )
        You are using an unsupported version of LLVM!
        Currently only 3.7 is supported.
        We will try though...
    
    Before:
    
        [1 of 1] Compiling Main             ( Main.hs, Main.o )
    
        <no location info>:
            Warning: Couldn't figure out LLVM version!
                     Make sure you have installed LLVM
        ghc: could not execute: opt
    
    After:
    
        [1 of 1] Compiling Main             ( Main.hs, Main.o )
    
        <no location info>: error:
            Warning: Couldn't figure out LLVM version!
                     Make sure you have installed LLVM 3.7
        ghc-stage1: could not execute: opt
    
    Reviewers: austin, rwbarton, bgamari
    
    Subscribers: thomie
    
    Differential Revision: https://phabricator.haskell.org/D1658


>---------------------------------------------------------------

0e9a331f25c89c6150a43d7d5d27ef5cb6e057ec
 compiler/llvmGen/LlvmCodeGen.hs      | 3 +++
 compiler/llvmGen/LlvmCodeGen/Base.hs | 5 ++++-
 compiler/main/SysTools.hs            | 5 ++++-
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/compiler/llvmGen/LlvmCodeGen.hs b/compiler/llvmGen/LlvmCodeGen.hs
index 3453484..3c63aa0 100644
--- a/compiler/llvmGen/LlvmCodeGen.hs
+++ b/compiler/llvmGen/LlvmCodeGen.hs
@@ -54,6 +54,9 @@ llvmCodeGen dflags h us cmm_stream
        let doWarn = wopt Opt_WarnUnsupportedLlvmVersion dflags
        when (ver /= supportedLlvmVersion && doWarn) $
            putMsg dflags (text "You are using an unsupported version of LLVM!"
+                            $+$ text ("Currently only " ++
+                                      llvmVersionStr supportedLlvmVersion ++
+                                      " is supported.")
                             $+$ text "We will try though...")
 
        -- run code generation
diff --git a/compiler/llvmGen/LlvmCodeGen/Base.hs b/compiler/llvmGen/LlvmCodeGen/Base.hs
index 3367cda..82c1eea 100644
--- a/compiler/llvmGen/LlvmCodeGen/Base.hs
+++ b/compiler/llvmGen/LlvmCodeGen/Base.hs
@@ -12,7 +12,7 @@ module LlvmCodeGen.Base (
         LiveGlobalRegs,
         LlvmUnresData, LlvmData, UnresLabel, UnresStatic,
 
-        LlvmVersion, supportedLlvmVersion,
+        LlvmVersion, supportedLlvmVersion, llvmVersionStr,
 
         LlvmM,
         runLlvm, liftStream, withClearVars, varLookup, varInsert,
@@ -184,6 +184,9 @@ type LlvmVersion = (Int, Int)
 supportedLlvmVersion :: LlvmVersion
 supportedLlvmVersion = sUPPORTED_LLVM_VERSION
 
+llvmVersionStr :: LlvmVersion -> String
+llvmVersionStr (major, minor) = show major ++ "." ++ show minor
+
 -- ----------------------------------------------------------------------------
 -- * Environment Handling
 --
diff --git a/compiler/main/SysTools.hs b/compiler/main/SysTools.hs
index c7ca4a6..4166b9b 100644
--- a/compiler/main/SysTools.hs
+++ b/compiler/main/SysTools.hs
@@ -66,6 +66,8 @@ import Util
 import DynFlags
 import Exception
 
+import LlvmCodeGen.Base (llvmVersionStr, supportedLlvmVersion)
+
 import Data.IORef
 import Control.Monad
 import System.Exit
@@ -653,7 +655,8 @@ figureLlvmVersion dflags = do
                 errorMsg dflags $ vcat
                     [ text "Warning:", nest 9 $
                           text "Couldn't figure out LLVM version!" $$
-                          text "Make sure you have installed LLVM"]
+                          text ("Make sure you have installed LLVM " ++
+                                llvmVersionStr supportedLlvmVersion) ]
                 return Nothing)
   return ver