Add rationale for the MAP_ANONYMOUS vs. MAP_ANON flags.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@7368 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/ExecutionEngine/JIT/JITEmitter.cpp b/lib/ExecutionEngine/JIT/JITEmitter.cpp
index e6dc706d55f0c06ab6bc9129997665b88d77fce4..9e62f13ce73bd70ed76c2e6f6a01a2bdd4949cfe 100644 (file)
--- a/lib/ExecutionEngine/JIT/JITEmitter.cpp
+++ b/lib/ExecutionEngine/JIT/JITEmitter.cpp
@@ -73,6 +73,7 @@ static void *getMemory(unsigned NumPages) {
   static const long pageSize = sysconf(_SC_PAGESIZE);
 
 #if defined(i386) || defined(__i386__) || defined(__x86__)
+  /* Linux and *BSD tend to have these flags named differently. */
 #if defined(MAP_ANON) && !defined(MAP_ANONYMOUS)
 # define MAP_ANONYMOUS MAP_ANON
 #endif