On Sat, Dec 24, 2011 at 8:00 PM, Steven Bosscher <stevenb....@gmail.com> wrote: > On Tue, Dec 20, 2011 at 9:46 AM, Tristan Gingold <ging...@adacore.com> wrote: >> Hi, >> >> currently alpha/vms backend emits a trampoline entry point for all nested >> functions. This is a waste of code space, as although nested functions are >> very common in Ada, address of nested functions are only seldom taken. >> >> The fact that the address of a function is taken seems only be available in >> cgraph. Is it OK to use cgraph in alpha.c ? > > Since no-one has answered yet, I'll just toss in my $0.02. > (Hold on to them a bit, they may be worth a million Euro soon :-) > > I think that in general you cannot rely on cgraph in the backends, > this has to be analyzed case-by-case. In your case I'm not sure, but I > think it should be OK. > > Your patch uses cgraph in alpha_start_function, which is apparently > only used for the target hook ASM_DECLARE_FUNCTION_NAME. This hook is > called from varasm.c:assemble_start_function(), and this is in turn > only called from final.c:rest_of_handle_final() to generate assembly > from RTL, and from cgraphunit.c:assemble_thunk() to output assembly > for MI thunks. AFAICT cgraph should be correct and complete at the > stage when those two functions are called. Therefore your patch should > be OK. > > Perhaps Honza can throw in his 0.02h?
Err - are not _all_ backends using trampolines to represent address-taken nested functions? At least I remeber to see them for x86 and plain C nested functions as well. So - is this really a target issue? At the time the address of a nested fn is taken the C frontend arranges to (dynamically?) create the trampoline via some builtin. Richard. > Ciao! > Steven
