[commit: ghc] master: osElfTarget should default to False (#5733) (a8b8d65)

[Simon Marlow]

Repository : ssh://darcs.haskell.org//srv/darcs/ghc

On branch  : master

http://hackage.haskell.org/trac/ghc/changeset/a8b8d657807ff89fb94aecaefd65b6ab3e3b39e0

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

commit a8b8d657807ff89fb94aecaefd65b6ab3e3b39e0
Author: Simon Marlow <marlowsd at gmail.com>
Date:   Wed Jan 4 11:39:55 2012 +0000

    osElfTarget should default to False (#5733)
    
    Another portabilty regression: before Platform we used to use elf_OBJ_FORMAT:
    
     #if linux_TARGET_OS || freebsd_TARGET_OS || openbsd_TARGET_OS || solaris2_TARGET_OS
     #define elf_OBJ_FORMAT 1
     #endif
    
    which defaults to undefined on unknown platforms.  Defaulting to
    non-ELF is correct, it just means that we won't rely on ELF-specific
    functionality.  I've added a comment to explain that.

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

 compiler/utils/Platform.hs |    9 +++++----
 1 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/compiler/utils/Platform.hs b/compiler/utils/Platform.hs
index 68f46e7..10b19fe 100644
--- a/compiler/utils/Platform.hs
+++ b/compiler/utils/Platform.hs
@@ -14,8 +14,6 @@ module Platform (
 
 where
 
-import Panic
-
 -- | Contains enough information for the native code generator to emit
 --      code for this platform.
 data Platform
@@ -89,5 +87,8 @@ osElfTarget OSNetBSD   = True
 osElfTarget OSSolaris2 = True
 osElfTarget OSDarwin   = False
 osElfTarget OSMinGW32  = False
-osElfTarget OSUnknown  = panic "Don't know if OSUnknown is elf"
-
+osElfTarget OSUnknown  = False
+ -- Defaulting to False is safe; it means don't rely on any
+ -- ELF-specific functionality.  It is important to have a default for
+ -- portability, otherwise we have to answer this question for every
+ -- new platform we compile on (even unreg).