[Support] Re-add the special OSX flags on mmap.
The problem appears to be that these flags can only be used
when mapping a file for read-only, not for readwrite. So
we do that here.
llvm-svn: 295880
diff --git a/llvm/lib/Support/Unix/Path.inc b/llvm/lib/Support/Unix/Path.inc
index 56fa01a..629a04b 100644
--- a/llvm/lib/Support/Unix/Path.inc
+++ b/llvm/lib/Support/Unix/Path.inc
@@ -551,6 +551,25 @@
int flags = (Mode == readwrite) ? MAP_SHARED : MAP_PRIVATE;
int prot = (Mode == readonly) ? PROT_READ : (PROT_READ | PROT_WRITE);
+#if defined(__APPLE__)
+ //----------------------------------------------------------------------
+ // Newer versions of MacOSX have a flag that will allow us to read from
+ // binaries whose code signature is invalid without crashing by using
+ // the MAP_RESILIENT_CODESIGN flag. Also if a file from removable media
+ // is mapped we can avoid crashing and return zeroes to any pages we try
+ // to read if the media becomes unavailable by using the
+ // MAP_RESILIENT_MEDIA flag. These flags are only usable when mapping
+ // with PROT_READ, so take care not to specify them otherwise.
+ //----------------------------------------------------------------------
+ if (Mode == readonly) {
+#if defined(MAP_RESILIENT_CODESIGN)
+ flags |= MAP_RESILIENT_CODESIGN;
+#endif
+#if defined(MAP_RESILIENT_MEDIA)
+ flags |= MAP_RESILIENT_MEDIA;
+#endif
+ }
+#endif // #if defined (__APPLE__)
Mapping = ::mmap(nullptr, Size, prot, flags, FD, Offset);
if (Mapping == MAP_FAILED)