rts: Introduce mmapAnonForLinker

Previously most of the uses of mmapForLinker were mapping anonymous
memory, resulting in a great deal of unnecessary repetition. Factor this
out into a new helper.

Also fixes a few places where error checking was missing or suboptimal.

1 files changed, 11 insertions, 1 deletions

diff --git a/rts/Linker.c b/rts/Linker.c
index ef08a282dc..6873b1a9b7 100644
--- a/rts/Linker.c
+++ b/rts/Linker.c
@@ -1080,7 +1080,7 @@ mmap_again:
                fixed = MAP_FIXED;
                goto mmap_again;
 #else
-               errorBelch("loadObj: failed to mmap() memory below 2Gb; "
+               errorBelch("mmapForLinker: failed to mmap() memory below 2Gb; "
                           "asked for %lu bytes at %p. "
                           "Try specifying an address with +RTS -xm<addr> -RTS",
                           size, map_addr);
@@ -1140,6 +1140,16 @@ mmap_again:
    return result;
 }
 
+/*
+ * Map read/write pages in low memory. Returns NULL on failure.
+ */
+void *
+mmapAnonForLinker (size_t bytes)
+{
+  return mmapForLinker (bytes, PROT_READ|PROT_WRITE, MAP_ANONYMOUS, -1, 0);
+}
+
+
 /* Note [Memory protection in the linker]
  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  * For many years the linker would simply map all of its memory