From 5e1b31bf5588cd9ea0b16e94fcc1d908e40027e2 Mon Sep 17 00:00:00 2001 From: David Greene Date: Thu, 10 Jan 2013 18:17:54 +0000 Subject: [PATCH] Fix Alias Bug Use memcpy to do type punning instead of a cast. A cast or similar operation through a union breaks strict aliasing rules. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172081 91177308-0d34-0410-b5e6-96231b3b80d8 --- unittests/Support/YAMLIOTest.cpp | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/unittests/Support/YAMLIOTest.cpp b/unittests/Support/YAMLIOTest.cpp index afa71cc25ea..a39fbebf295 100644 --- a/unittests/Support/YAMLIOTest.cpp +++ b/unittests/Support/YAMLIOTest.cpp @@ -783,10 +783,18 @@ namespace yaml { static void mapping(IO &io, KindAndFlags& kf) { io.mapRequired("kind", kf.kind); // type of flags field varies depending on kind field - if ( kf.kind == kindA ) - io.mapRequired("flags", *((AFlags*)&kf.flags)); - else - io.mapRequired("flags", *((BFlags*)&kf.flags)); + + // Use memcpy here to avoid breaking strict aliasing rules. + if ( kf.kind == kindA ) { + AFlags aflags; + memcpy(&aflags, &kf.flags, sizeof(aflags)); + io.mapRequired("flags", aflags); + } + else { + BFlags bflags; + memcpy(&bflags, &kf.flags, sizeof(bflags)); + io.mapRequired("flags", bflags); + } } }; } -- 2.11.0