On Fri, Aug 12, 2011 at 5:38 AM, Pedro Alves <pe...@codesourcery.com> wrote: > On Friday 12 August 2011 13:17:21, Paolo Bonzini wrote: >> 2011-08-12 Paolo Bonzini <bonz...@gnu.org> >> >> * Makefile.in (install-unwind_h): Create >> $(gcc_objdir)/include/unwind.h >> atomically. >> >> Index: Makefile.in >> =================================================================== >> --- Makefile.in (revision 177688) >> +++ Makefile.in (working copy) >> @@ -991,8 +1001,10 @@ gcc-extra-parts: >> all: $(extra-parts) >> >> install-unwind_h: >> - rm -f $(gcc_objdir)/include/unwind.h >> - cp unwind.h $(gcc_objdir)/include/unwind.h >> + cp unwind.h $(gcc_objdir)/include/tmp-unwind.h >> + sh $(srcdir)/../move-if-change \ >> + $(gcc_objdir)/include/tmp-unwind.h \ >> + $(gcc_objdir)/include/unwind.h >> chmod a+r $(gcc_objdir)/include/unwind.h >> > > Can't this sequence happen? > > proc1: cp unwind.h $(gcc_objdir)/include/tmp-unwind.h > proc2: cp unwind.h $(gcc_objdir)/include/tmp-unwind.h > proc1: sh $(srcdir)/../move-if-change \ > $(gcc_objdir)/include/tmp-unwind.h \ > $(gcc_objdir)/include/unwind.h > proc2: sh $(srcdir)/../move-if-change \ > $(gcc_objdir)/include/tmp-unwind.h \ > $(gcc_objdir)/include/unwind.h > > It sounds like the latter move-if-change could trip on > a non-extant tmp-unwind.h. >
Yes, we should use an unique tmp unwind.h. -- H.J.
