Make the Google Go programming language available on GNU/Hurd in its GCC gccgo implementation, and enable Hurd-specific features.

There is a FOSS Factory bounty (p263) on this task.

---

Part I

First, make the language functional, have its test suite pass without errors.

Original GSoC Task Description

Svante's work

Per id:"1335509732.3707.179.camel@hp.my.own.domain", Svante has been working on this, has some (unpublished) patches, and this is currently blocked on getcontext/setcontext.

getcontext/makecontext/setcontext/swapcontext usage analysis

In context of tls-threadvar. Looking at GCC trunk commit f6568ea476aa52a6e23c6db43b3e240cde55783a (2013-04-26).

The check in libgo/configure.ac whether setcontext clobbers TLS variables is invalid on GNU Hurd.

The *context functions are used in libgo/runtime/go-signal.c and libgo/runtime/proc.c.

__splitstack_getcontext, __splitstack_setcontext, __splitstack_makecontext, __splitstack_resetcontext, __splitstack_block_signals_context are to be provided by libgcc. However, in said libgo runtime files, they're used only #ifdef USING_SPLIT_STACK. ?I would assume that before we can enable split stacks, first tls-threadvar needs to be fixed.

In libgo/runtime/proc.c:runtime_gogo, setcontext is used to switch context to a different goroutine. TODO.

In libgo/runtime/proc.c:runtime_mcall, which save[s] context and call[s] fn passing g as a parameter, getcontext and setcontext are used; this is only called from libgo/runtime/proc.c:runtime_gosched. TODO.

In libgo/runtime/proc.c:runtime_tracebackothers, getcontext is used to switch context to the goroutine. TODO.

In libgo/runtime/proc.c:runtime_mstart, which is called to start an M, getcontext is used. TODO.

In libgo/runtime/proc.c:runtime_entersyscall, which is called when the goroutine g is about to enter a system call, getcontext is used to save the registers in the g structure so that any pointers held in registers will be seen by the garbage collector. Should be fine.

In libgo/runtime/proc.c:__go_go, getcontext and makecontext are used. TODO.

In libgo/runtime/thread.c:runtime_minit, which is [c]alled to initialize a new m (including the bootstrap m), ss.ss_sp is set to a new stack retrieved via libgo/runtime/proc.c:runtime_malg, which allocate[s] a new g, with a stack [...], and then sigaltstack is called. TODO.

libgo/runtime/go-signal.c:  /* We are now running on the stack registered via sigaltstack.
libgo/runtime/go-signal.c:     and sigaltstack when the program starts.)  */

libgo/runtime/proc.c:         vnewg->context.uc_stack.ss_sp = vsp;
libgo/runtime/proc.c:         vnewg->context.uc_stack.ss_sp += vspsize;
libgo/runtime/proc.c:         vnewg->context.uc_stack.ss_size = vspsize;

Also, in libgo/runtime/proc.c:runtime_newm, pthread_attr_setstacksize is used, which we also can't support yet, for the same reason.

---

Part II

Next, Hurd-specific features can be added. Add an interface to the language/environment for being able to do RPC calls, in order to program translators natively in the Google Go programming language.

Original GSoC Task Description