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Change the setup so that rust_activate_glue returns to rust_exit_task_glue

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and rust_exit_task_glue calls the rust main.

This is simpler since we only need to setup one frame. It also matches
what ld.so does, so gdb is happy and stops a backtrace at rust_exit_task_glue
instead of continuing past whatever function happened to be before
rust_exit_task_glue is the object file.

This is the rt part and should be merged after the rust0 part.
This commit is contained in:
Rafael Ávila de Espíndola
2011-05-05 14:01:16 -04:00
committed by Graydon Hoare
parent d85260bcc5
commit d6deeffd95
1 changed files with 19 additions and 38 deletions
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57
src/rt/rust_task.cpp
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@@ -254,9 +254,9 @@ rust_task::start_rustboot(uintptr_t exit_task_glue,
void void
rust_task::start_rustc(uintptr_t exit_task_glue, rust_task::start_rustc(uintptr_t exit_task_glue,
uintptr_t spawnee_fn, uintptr_t spawnee_fn,
uintptr_t args, uintptr_t args,
size_t callsz) size_t callsz)
{ {
LOGPTR(dom, "exit-task glue", exit_task_glue); LOGPTR(dom, "exit-task glue", exit_task_glue);
LOGPTR(dom, "from spawnee", spawnee_fn); LOGPTR(dom, "from spawnee", spawnee_fn);
@@ -271,27 +271,18 @@ rust_task::start_rustc(uintptr_t exit_task_glue,
// see: "Mac OS X ABI Function Call Guide" // see: "Mac OS X ABI Function Call Guide"
// Begin synthesizing frames. There are two: a "fully formed" // Begin synthesizing the exit_task_glue frame. We will return to
// exit-task frame at the top of the stack -- that pretends to be // exit_task_glue and it is responsible for calling the user code
// mid-execution -- and a just-starting frame beneath it that // and passing the value returned by the user to the system
// starts executing the first instruction of the spawnee. The // exit routine.
// spawnee *thinks* it was called by the exit-task frame above
// it. It wasn't; we put that fake frame in place here, but the
// illusion is enough for the spawnee to return to the exit-task
// frame when it's done, and exit.
uintptr_t *spp = (uintptr_t *)rust_sp; uintptr_t *spp = (uintptr_t *)rust_sp;
uintptr_t dummy_ret = (uintptr_t) spp--;
// The exit_task_glue frame we synthesize above the frame we activate: uintptr_t args_size = callsz - 3*sizeof(uintptr_t);
make_aligned_room_for_bytes(spp, 2 * sizeof(uintptr_t)); uintptr_t frame_size = args_size + 4*sizeof(uintptr_t);
*spp-- = (uintptr_t) 0; // closure-or-obj
*spp-- = (uintptr_t) this; // task
I(dom, spp == align_down(spp));
*spp-- = (uintptr_t) 0x0; // output
*spp-- = (uintptr_t) 0x0; // retpc
I(dom, args); make_aligned_room_for_bytes(spp, frame_size);
make_aligned_room_for_bytes(spp, callsz - 3 * sizeof(uintptr_t));
// Copy args from spawner to spawnee. // Copy args from spawner to spawnee.
uintptr_t *src = (uintptr_t *)args; uintptr_t *src = (uintptr_t *)args;
@@ -299,29 +290,19 @@ rust_task::start_rustc(uintptr_t exit_task_glue,
src += 1; // spawn-call task slot src += 1; // spawn-call task slot
src += 1; // spawn-call closure-or-obj slot src += 1; // spawn-call closure-or-obj slot
// Undo previous sp-- so we're pointing at the last word pushed. *spp-- = (uintptr_t) *src; // vec
++spp; *spp-- = (uintptr_t) 0x0; // closure-or-obj
*spp-- = (uintptr_t) this; // task
*spp-- = (uintptr_t) dummy_ret; // output address
// Memcpy all but the task, output and env pointers *spp-- = (uintptr_t) (uintptr_t) spawnee_fn;
callsz -= (3 * sizeof(uintptr_t));
spp = (uintptr_t*) (((uintptr_t)spp) - callsz);
memcpy(spp, src, callsz);
// Move sp down to point to last implicit-arg cell (env). I(dom, spp == align_down(spp));
spp--;
// The *implicit* incoming args to the spawnee frame we're *spp-- = (uintptr_t) 0x0; // retp
// activating:
*spp-- = (uintptr_t) 0x0; // closure-or-obj
// in FASTCALL mode we don't, the outptr will be in ecx and the task *spp-- = (uintptr_t) exit_task_glue;
// in edx, and the activate_glue will make sure to set that up.
I(dom, spp+1 == align_down(spp+1));
*spp-- = (uintptr_t) exit_task_glue; // retpc
// The context the activate_glue needs to switch stack.
*spp-- = (uintptr_t) spawnee_fn; // instruction to start at
for (size_t j = 0; j < n_callee_saves; ++j) { for (size_t j = 0; j < n_callee_saves; ++j) {
*spp-- = (uintptr_t)NULL; *spp-- = (uintptr_t)NULL;
} }