[commit: ghc] master: Don't use mmap symbols when !RTS_LINKER_USE_MMAP (a637eeb)

[git at git.haskell.org]

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

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/a637eeb7a1852adfd99b06d2c0a3496e4f238a0c/ghc

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

commit a637eeb7a1852adfd99b06d2c0a3496e4f238a0c
Author: Shea Levy <shea at shealevy.com>
Date:   Tue Nov 15 22:01:20 2016 -0500

    Don't use mmap symbols when !RTS_LINKER_USE_MMAP
    
    Some usages of symbols from sys/mman.h are guarded by
    RTS_LINKER_USE_MMAP by C conditionals, not CPP conditionals. Since those
    branches are dead anyway when !RTS_LINKER_USE_MMAP, we just stub out the
    relevant symbols rather than increasing CPP branching.
    
    Fixes #12839.
    
    Reviewers: simonmar, austin, bgamari, erikd
    
    Reviewed By: simonmar, bgamari, erikd
    
    Subscribers: thomie
    
    Differential Revision: https://phabricator.haskell.org/D2710
    
    GHC Trac Issues: #12839


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

a637eeb7a1852adfd99b06d2c0a3496e4f238a0c
 rts/LinkerInternals.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/rts/LinkerInternals.h b/rts/LinkerInternals.h
index 60370bb..4806d53 100644
--- a/rts/LinkerInternals.h
+++ b/rts/LinkerInternals.h
@@ -303,4 +303,14 @@ char *cstring_from_section_name(
 #  define OBJFORMAT_MACHO
 #endif
 
+/* In order to simplify control flow a bit, some references to mmap-related
+   definitions are blocked off by a C-level if statement rather than a CPP-level
+   #if statement. Since those are dead branches when !RTS_LINKER_USE_MMAP, we
+   just stub out the relevant symbols here
+*/
+#if !RTS_LINKER_USE_MMAP
+#define munmap(x,y) /* nothing */
+#define MAP_ANONYMOUS 0
+#endif
+
 #endif /* LINKERINTERNALS_H */