From f85fdf59c91fe4aa56633347268d144d3e075844 Mon Sep 17 00:00:00 2001 From: Andreas Krebbel Date: Mon, 18 Dec 2023 17:54:42 +0100 Subject: [PATCH] IBM Z: Cover weak symbols with -munaligned-symbols With the recently introduced -munaligned-symbols option byte-sized variables which are resolved externally are considered to be potentially misaligned. However, this should rather also be applied to symbols which resolve locally if they are weak. Done with this patch. gcc/ChangeLog: * config/s390/s390.cc (s390_encode_section_info): Replace SYMBOL_REF_LOCAL_P with decl_binds_to_current_def_p. gcc/testsuite/ChangeLog: * gcc.target/s390/unaligned-2.c: New test. --- gcc/config/s390/s390.cc | 6 ++---- gcc/testsuite/gcc.target/s390/unaligned-2.c | 16 ++++++++++++++++ 2 files changed, 18 insertions(+), 4 deletions(-) create mode 100644 gcc/testsuite/gcc.target/s390/unaligned-2.c diff --git a/gcc/config/s390/s390.cc b/gcc/config/s390/s390.cc index 044de874590..a5c36b43972 100644 --- a/gcc/config/s390/s390.cc +++ b/gcc/config/s390/s390.cc @@ -13802,10 +13802,8 @@ s390_encode_section_info (tree decl, rtx rtl, int first) byte aligned as mandated by our ABI. This behavior can be overridden for external symbols with the -munaligned-symbols switch. */ - if (DECL_ALIGN (decl) % 16 - && (DECL_USER_ALIGN (decl) - || (!SYMBOL_REF_LOCAL_P (XEXP (rtl, 0)) - && s390_unaligned_symbols_p))) + if ((DECL_USER_ALIGN (decl) && DECL_ALIGN (decl) % 16) + || (s390_unaligned_symbols_p && !decl_binds_to_current_def_p (decl))) SYMBOL_FLAG_SET_NOTALIGN2 (XEXP (rtl, 0)); else if (DECL_ALIGN (decl) % 32) SYMBOL_FLAG_SET_NOTALIGN4 (XEXP (rtl, 0)); diff --git a/gcc/testsuite/gcc.target/s390/unaligned-2.c b/gcc/testsuite/gcc.target/s390/unaligned-2.c new file mode 100644 index 00000000000..c1ece6d5935 --- /dev/null +++ b/gcc/testsuite/gcc.target/s390/unaligned-2.c @@ -0,0 +1,16 @@ +/* weak symbols might get overridden in another module by symbols + which are not aligned on a 2-byte boundary. Although this violates + the zABI we try to handle this gracefully by not using larl on + these symbols if -munaligned-symbols has been specified. */ + +/* { dg-do compile } */ +/* { dg-options "-O3 -march=z900 -fno-section-anchors -munaligned-symbols" } */ +unsigned char __attribute__((weak)) weaksym = 0; + +unsigned char +foo () +{ + return weaksym; +} + +/* { dg-final { scan-assembler-times "larl\t%r\[0-9\]*,weaksym\n" 0 } } */