From 661298358c4c84ffacbc266321227a9b6efc7a3b Mon Sep 17 00:00:00 2001 From: Shenghou Ma Date: Mon, 19 May 2014 22:39:42 -0400 Subject: [PATCH] cmd/ld: abort if (32-bit) address relocation is negative on amd64. Update #7980 This CL make the linker abort for the example program. For Go 1.4, we need to find a general way to handle large memory model programs. LGTM=dave, josharian, iant R=iant, dave, josharian CC=golang-codereviews https://golang.org/cl/91500046 --- src/cmd/ld/data.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/src/cmd/ld/data.c b/src/cmd/ld/data.c index 24969db55b..55d020710e 100644 --- a/src/cmd/ld/data.c +++ b/src/cmd/ld/data.c @@ -243,6 +243,16 @@ relocsym(LSym *s) break; } o = symaddr(r->sym) + r->add; + + // On amd64, 4-byte offsets will be sign-extended, so it is impossible to + // access more than 2GB of static data; fail at link time is better than + // fail at runtime. See http://golang.org/issue/7980. + // Instead of special casing only amd64, we treat this as an error on all + // 64-bit architectures so as to be future-proof. + if((int32)o < 0 && PtrSize > 4 && siz == 4) { + diag("non-pc-relative relocation address is too big: %#llux", o); + errorexit(); + } break; case R_CALL: case R_PCREL: -- 2.50.0