From a3afdb212742e28c6d309ae919e81c52afb44542 Mon Sep 17 00:00:00 2001 From: Mark Wielaard Date: Wed, 18 Dec 2013 18:02:42 +0100 Subject: [PATCH] backends: Avoid type-punning issue in s390_set_initial_registers_tid. Use union to avoid type-punning when assigning a double to a Dwarf_Word. gcc complains otherwise. error: dereferencing type-punned pointer will break strict-aliasing rules. Signed-off-by: Mark Wielaard --- backends/ChangeLog | 5 +++++ backends/s390_initreg.c | 15 +++++++++++++-- 2 files changed, 18 insertions(+), 2 deletions(-) diff --git a/backends/ChangeLog b/backends/ChangeLog index cb56d217c..23329d0a8 100644 --- a/backends/ChangeLog +++ b/backends/ChangeLog @@ -1,3 +1,8 @@ +2013-12-18 Mark Wielaard + + * 390_initreg.c (s390_set_initial_registers_tid): Use union + to avoid type-punning when assigning a double to a Dwarf_Word. + 2013-12-18 Jan Kratochvil unwinder: s390 and s390x diff --git a/backends/s390_initreg.c b/backends/s390_initreg.c index 62a1531e7..8fc54bc7c 100644 --- a/backends/s390_initreg.c +++ b/backends/s390_initreg.c @@ -68,8 +68,19 @@ s390_set_initial_registers_tid (pid_t tid __attribute__ ((unused)), eu_static_assert (sizeof user_regs.regs.fp_regs.fprs[0] == sizeof dwarf_regs[0]); for (unsigned u = 0; u < 16; u++) - dwarf_regs[u] = *((const __typeof (dwarf_regs[0]) *) - &user_regs.regs.fp_regs.fprs[u]); + { + // Store the double bits as is in the Dwarf_Word without conversion. + union + { + double d; + Dwarf_Word w; + } fpr = { .d = user_regs.regs.fp_regs.fprs[u] }; + dwarf_regs[u] = fpr.w; + } + if (! setfunc (16, 16, dwarf_regs, arg)) + return false; + dwarf_regs[0] = user_regs.regs.psw.addr; + if (! setfunc (16, 16, dwarf_regs, arg)) return false; dwarf_regs[0] = user_regs.regs.psw.addr; -- 2.47.2