On Fri, Apr 08, 2005 at 09:57:35AM -0700, H. J. Lu wrote: > On Thu, Apr 07, 2005 at 03:36:18PM -0700, James E Wilson wrote: > > H. J. Lu wrote: > > >Gcc 4,0 generates > > >.section .gnu.linkonce.t._ZN3FooC1Ev,"axG",@progbits,_ZN3FooC1Ev,comdat > > >for comdat group. Can gcc use > > >.section .text._ZN3FooC1Ev,"axG",@progbits,_ZN3FooC1Ev,comdat > > >instead? At least, there will be less characters for linker to process. > > > > I know of no reason why we must continue using .gnu.linkonce for targets > > that have proper comdat support. > > > > However, I don't think this will be an easy transition, because there > > are too many places that make assumptions about the fact that > > .gnu.linkonce has a special meaning. That might be an argument against > > even trying. > > > > For instance, in varasm.c, in default_function_rodata_section, we have > > /* For .gnu.linkonce.t.foo we want to use .gnu.linkonce.r.foo. */ > > if (DECL_ONE_ONLY (decl) && strncmp (name, ".gnu.linkonce.t.", > > 16) == 0) > > and this code fails if you remove the .gnu.linkonce from the section > > name. We'd need code to check for and handle a comdat section here. > > > > dwarf2out.c assumes that comdat sections for debugging start with > > .gnu.linkonce. > > I am not sure if dwarf2out.c supports comdat group at all: > > http://gcc.gnu.org/ml/gcc-patches/2005-04/msg00711.html > > > > > There are likely many other places that need fixing also. > > > > There is also the possible issue that using .text.foo conflicts with the > > naming scheme used by the -ffunction-sections -fdata-sections options. > > What happens if we have two sections both named .text.foo, one of which > > is a comdat section, and one of which came from -ffunction-sections? We > > The assembler with proper comdat group should be OK. I had to fix > the assembler to support dupulicated section names for comdat group. > For linker, input section names are only used to group sections for > output. >
There is another problem. set_named_section_flags in varasm.c assumes each section has a unique name. H.J.
