rust/src/rt/rust_upcall.cpp
2013-08-16 13:24:25 -07:00

130 lines
4.1 KiB
C++

// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
/*
Upcalls
These are runtime functions that the compiler knows about and generates
calls to. They are called on the Rust stack and, in most cases, immediately
switch to the C stack.
*/
#include "rust_globals.h"
#include "rust_util.h"
//Unwinding ABI declarations.
typedef int _Unwind_Reason_Code;
typedef int _Unwind_Action;
struct _Unwind_Context;
struct _Unwind_Exception;
typedef void (*CDECL stack_switch_shim)(void*);
/**********************************************************************
* Switches to the C-stack and invokes |fn_ptr|, passing |args| as argument.
* This is used by the C compiler to call foreign functions and by other
* upcalls to switch to the C stack. The return value is passed through a
* field in the args parameter. This upcall is specifically for switching
* to the shim functions generated by rustc.
*/
extern "C" CDECL void
upcall_call_shim_on_c_stack(void *args, void *fn_ptr) {
stack_switch_shim f = (stack_switch_shim)fn_ptr;
f(args);
}
/*
* The opposite of above. Starts on a C stack and switches to the Rust
* stack. This is the only upcall that runs from the C stack.
*/
extern "C" CDECL void
upcall_call_shim_on_rust_stack(void *args, void *fn_ptr) {
// There's no task. Call the function and hope for the best
stack_switch_shim f = (stack_switch_shim)fn_ptr;
f(args);
}
/**********************************************************************/
extern "C" _Unwind_Reason_Code
__gxx_personality_v0(int version,
_Unwind_Action actions,
uint64_t exception_class,
_Unwind_Exception *ue_header,
_Unwind_Context *context);
struct s_rust_personality_args {
_Unwind_Reason_Code retval;
int version;
_Unwind_Action actions;
uint64_t exception_class;
_Unwind_Exception *ue_header;
_Unwind_Context *context;
};
extern "C" void
upcall_s_rust_personality(s_rust_personality_args *args) {
args->retval = __gxx_personality_v0(args->version,
args->actions,
args->exception_class,
args->ue_header,
args->context);
}
/**
The exception handling personality function. It figures
out what to do with each landing pad. Just a stack-switching
wrapper around the C++ personality function.
*/
extern "C" _Unwind_Reason_Code
upcall_rust_personality(int version,
_Unwind_Action actions,
uint64_t exception_class,
_Unwind_Exception *ue_header,
_Unwind_Context *context) {
s_rust_personality_args args = {(_Unwind_Reason_Code)0,
version, actions, exception_class,
ue_header, context};
upcall_s_rust_personality(&args);
return args.retval;
}
// NB: This needs to be blazing fast. Don't switch stacks
extern "C" CDECL void *
upcall_new_stack(size_t stk_sz, void *args_addr, size_t args_sz) {
assert(false && "newsched shouldn't be growing the stack");
return NULL;
}
// NB: This needs to be blazing fast. Don't switch stacks
extern "C" CDECL void
upcall_del_stack() {
assert(false && "newsched shouldn't be growing the stack");
}
// Landing pads need to call this to insert the
// correct limit into TLS.
// NB: This must run on the Rust stack because it
// needs to acquire the value of the stack pointer
extern "C" CDECL void
upcall_reset_stack_limit() {
}
//
// Local Variables:
// mode: C++
// fill-column: 78;
// indent-tabs-mode: nil
// c-basic-offset: 4
// buffer-file-coding-system: utf-8-unix
// End:
//