Extract derived constants from nm output for various OSes differently.

Fixes #8783.

In order to avoid querying the nm version that does not work on Mac OS X
we use the "nm -P" output that is supposed to produce (more portable)
POSIX output and works on all tested OSes (MinGW, Mac OS X, Solaris and
Linux using GNU nm) although slightly different (as documented). The "nm
-P" output is actually only needed to recognize the output of a non-GNU
Solaris nm (all other OSes produce sane outut using "nm" only).

Signed-off-by: Austin Seipp <austin@well-typed.com>

1 files changed, 15 insertions, 22 deletions

diff --git a/utils/deriveConstants/DeriveConstants.hs b/utils/deriveConstants/DeriveConstants.hs
index 8c943f0584..6bfce247d3 100644
--- a/utils/deriveConstants/DeriveConstants.hs
+++ b/utils/deriveConstants/DeriveConstants.hs
@@ -641,7 +641,7 @@ getWanted verbose tmpdir gccProgram gccFlags nmProgram
              oFile = tmpdir </> "tmp.o"
          writeFile cFile cStuff
          execute verbose gccProgram (gccFlags ++ ["-c", cFile, "-o", oFile])
-         xs <- readProcess nmProgram [oFile] ""
+         xs <- readProcess nmProgram ["-P", oFile] ""
          let ls = lines xs
              ms = map parseNmLine ls
              m = Map.fromList $ catMaybes ms
@@ -710,28 +710,21 @@ getWanted verbose tmpdir gccProgram gccFlags nmProgram
           doWanted (ClosurePayloadMacro {}) = []
           doWanted (FieldTypeGcptrMacro {}) = []
 
-          -- parseNmLine parses nm output that looks like
-          -- "0000000b C derivedConstantMAX_Vanilla_REG"
+          -- parseNmLine parses "nm -P" output that looks like
+          -- "derivedConstantMAX_Vanilla_REG C 0000000b 0000000b" (GNU nm)
+          -- "_derivedConstantMAX_Vanilla_REG C b 0" (Mac OS X)
+          -- "_derivedConstantMAX_Vanilla_REG C 000000b" (MinGW)
+          -- "derivedConstantMAX_Vanilla_REG D        1        b" (Solaris)
           -- and returns ("MAX_Vanilla_REG", 11)
-          parseNmLine xs0 = case break (' ' ==) xs0 of
-                            (x1, ' ' : xs1) ->
-                                case break (' ' ==) xs1 of
-                                (x2, ' ' : x3) ->
-                                    case readHex x1 of
-                                    [(size, "")] ->
-                                        case x2 of
-                                        "C" ->
-                                            let x3' = case x3 of
-                                                      '_' : rest -> rest
-                                                      _          -> x3
-                                            in case stripPrefix prefix x3' of
-                                               Just name ->
-                                                   Just (name, size)
-                                               _ -> Nothing
-                                        _ -> Nothing
-                                    _ -> Nothing
-                                _ -> Nothing
-                            _ -> Nothing
+          parseNmLine line
+              = case words line of
+                ('_' : n) : "C" : s : _ -> mkP n s
+                n : "C" : s : _ -> mkP n s
+                [n, "D", _, s] -> mkP n s
+                _ -> Nothing
+              where mkP r s = case (stripPrefix prefix r, readHex s) of
+                        (Just name, [(size, "")]) -> Just (name, size)
+                        _ -> Nothing
 
           -- If an Int value is larger than 2^28 or smaller
           -- than -2^28, then fail.