src/rt/rust_upcall.cpp - rust - Git at Google

 // 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_task.h"
 #include "rust_sched_loop.h"
 #include "rust_unwind.h"
 #include "rust_upcall.h"
 #include "rust_util.h"

 #ifdef __GNUC__
 #define LOG_UPCALL_ENTRY(task)                            \
     LOG(task, upcall,                                     \
         "> UPCALL %s - task: %s 0x%" PRIxPTR              \
         " retpc: x%" PRIxPTR,                             \
         __FUNCTION__,                                     \
         (task)->name, (task),                             \
         __builtin_return_address(0));
 #else
 #define LOG_UPCALL_ENTRY(task)                            \
     LOG(task, upcall, "> UPCALL task: %s @x%" PRIxPTR,    \
         (task)->name, (task));
 #endif

 #define UPCALL_SWITCH_STACK(T, A, F) \
     call_upcall_on_c_stack(T, (void*)A, (void*)F)

 inline void
 call_upcall_on_c_stack(rust_task *task, void *args, void *fn_ptr) {
     task->call_on_c_stack(args, fn_ptr);
 }

 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) {
     rust_task *task = rust_try_get_current_task();

     if (task) {
         // We're running in task context, do a stack switch
         try {
             task->call_on_c_stack(args, fn_ptr);
         } catch (...) {
             // Logging here is not reliable
             assert(false && "Foreign code threw an exception");
         }
     } else {
         // There's no task. Call the function and hope for the best
         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) {
     rust_task *task = rust_try_get_current_task();

     if (task) {
         try {
             task->call_on_rust_stack(args, fn_ptr);
         } catch (...) {
             // We can't count on being able to unwind through arbitrary
             // code. Our best option is to just fail hard.
             // Logging here is not reliable
             assert(false
                    && "Rust task failed after reentering the Rust stack");
         }
     } else {
         // There's no task. Call the function and hope for the best
         stack_switch_shim f = (stack_switch_shim)fn_ptr;
         f(args);
     }
 }

 /**********************************************************************/

 struct s_fail_args {
     rust_task *task;
     char const *expr;
     char const *file;
     size_t line;
 };

 extern "C" CDECL void
 upcall_s_fail(s_fail_args *args) {
     rust_task *task = args->task;
     LOG_UPCALL_ENTRY(task);
     task->fail(args->expr, args->file, args->line);
 }

 extern "C" CDECL void
 upcall_fail(char const *expr,
             char const *file,
             size_t line) {
     rust_task *task = rust_try_get_current_task();
     if (task == NULL) {
         // FIXME #5161: Need to think about what to do here
         printf("failure outside of a task");
         abort();
     }
     s_fail_args args = {task,expr,file,line};
     UPCALL_SWITCH_STACK(task, &args, upcall_s_fail);
 }

 // FIXME (#2861): Alias used by libcore/rt.rs to avoid naming conflicts with
 // autogenerated wrappers for upcall_fail. Remove this when we fully move away
 // away from the C upcall path.
 extern "C" CDECL void
 rust_upcall_fail(char const *expr,
                  char const *file,
                  size_t line) {
     upcall_fail(expr, file, line);
 }

 struct s_trace_args {
     rust_task *task;
     char const *msg;
     char const *file;
     size_t line;
 };

 /**********************************************************************
  * Allocate an object in the task-local heap.
  */

 struct s_malloc_args {
     rust_task *task;
     uintptr_t retval;
     type_desc *td;
     uintptr_t size;
 };

 extern "C" CDECL void
 upcall_s_malloc(s_malloc_args *args) {
     rust_task *task = args->task;
     LOG_UPCALL_ENTRY(task);
     LOG(task, mem, "upcall malloc(0x%" PRIxPTR ")", args->td);

     rust_opaque_box *box = task->boxed.malloc(args->td, args->size);
     void *body = box_body(box);

     debug::maybe_track_origin(task, box);

     LOG(task, mem,
         "upcall malloc(0x%" PRIxPTR ") = box 0x%" PRIxPTR
         " with body 0x%" PRIxPTR,
         args->td, (uintptr_t)box, (uintptr_t)body);

     args->retval = (uintptr_t)box;
 }

 extern "C" CDECL uintptr_t
 upcall_malloc(type_desc *td, uintptr_t size) {
     rust_task *task = rust_get_current_task();
     s_malloc_args args = {task, 0, td, size};
     UPCALL_SWITCH_STACK(task, &args, upcall_s_malloc);
     return args.retval;
 }

 // FIXME (#2861): Alias used by libcore/rt.rs to avoid naming conflicts with
 // autogenerated wrappers for upcall_malloc. Remove this when we fully move
 // away away from the C upcall path.
 extern "C" CDECL uintptr_t
 rust_upcall_malloc(type_desc *td, uintptr_t size) {
     return upcall_malloc(td, size);
 }

 /**********************************************************************
  * Called whenever an object in the task-local heap is freed.
  */

 struct s_free_args {
     rust_task *task;
     void *ptr;
 };

 extern "C" CDECL void
 upcall_s_free(s_free_args *args) {
     rust_task *task = args->task;
     LOG_UPCALL_ENTRY(task);

     rust_sched_loop *sched_loop = task->sched_loop;
     DLOG(sched_loop, mem,
              "upcall free(0x%" PRIxPTR ", is_gc=%" PRIdPTR ")",
              (uintptr_t)args->ptr);

     debug::maybe_untrack_origin(task, args->ptr);

     rust_opaque_box *box = (rust_opaque_box*) args->ptr;
     task->boxed.free(box);
 }

 extern "C" CDECL void
 upcall_free(void* ptr) {
     rust_task *task = rust_get_current_task();
     s_free_args args = {task,ptr};
     UPCALL_SWITCH_STACK(task, &args, upcall_s_free);
 }

 // FIXME (#2861): Alias used by libcore/rt.rs to avoid naming conflicts with
 // autogenerated wrappers for upcall_free. Remove this when we fully move away
 // away from the C upcall path.
 extern "C" CDECL void
 rust_upcall_free(void* ptr) {
     upcall_free(ptr);
 }

 /**********************************************************************/

 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};
     rust_task *task = rust_get_current_task();

     // The personality function is run on the stack of the
     // last function that threw or landed, which is going
     // to sometimes be the C stack. If we're on the Rust stack
     // then switch to the C stack.

     if (task->on_rust_stack()) {
         UPCALL_SWITCH_STACK(task, &args, upcall_s_rust_personality);
     } else {
         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) {
     rust_task *task = rust_get_current_task();
     return task->next_stack(stk_sz,
                             args_addr,
                             args_sz);
 }

 // NB: This needs to be blazing fast. Don't switch stacks
 extern "C" CDECL void
 upcall_del_stack() {
     rust_task *task = rust_get_current_task();
     task->prev_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() {
     rust_task *task = rust_get_current_task();
     task->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:
 //
	// 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_task.h"
	#include "rust_sched_loop.h"
	#include "rust_unwind.h"
	#include "rust_upcall.h"
	#include "rust_util.h"

	#ifdef __GNUC__
	#define LOG_UPCALL_ENTRY(task) \
	LOG(task, upcall, \
	"> UPCALL %s - task: %s 0x%" PRIxPTR \
	" retpc: x%" PRIxPTR, \
	__FUNCTION__, \
	(task)->name, (task), \
	__builtin_return_address(0));
	#else
	#define LOG_UPCALL_ENTRY(task) \
	LOG(task, upcall, "> UPCALL task: %s @x%" PRIxPTR, \
	(task)->name, (task));
	#endif

	#define UPCALL_SWITCH_STACK(T, A, F) \
	call_upcall_on_c_stack(T, (void)A, (void)F)

	inline void
	call_upcall_on_c_stack(rust_task task, void args, void *fn_ptr) {
	task->call_on_c_stack(args, fn_ptr);
	}

	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) {
	rust_task *task = rust_try_get_current_task();

	if (task) {
	// We're running in task context, do a stack switch
	try {
	task->call_on_c_stack(args, fn_ptr);
	} catch (...) {
	// Logging here is not reliable
	assert(false && "Foreign code threw an exception");
	}
	} else {
	// There's no task. Call the function and hope for the best
	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) {
	rust_task *task = rust_try_get_current_task();

	if (task) {
	try {
	task->call_on_rust_stack(args, fn_ptr);
	} catch (...) {
	// We can't count on being able to unwind through arbitrary
	// code. Our best option is to just fail hard.
	// Logging here is not reliable
	assert(false
	&& "Rust task failed after reentering the Rust stack");
	}
	} else {
	// There's no task. Call the function and hope for the best
	stack_switch_shim f = (stack_switch_shim)fn_ptr;
	f(args);
	}
	}

	/**********************************************************************/

	struct s_fail_args {
	rust_task *task;
	char const *expr;
	char const *file;
	size_t line;
	};

	extern "C" CDECL void
	upcall_s_fail(s_fail_args *args) {
	rust_task *task = args->task;
	LOG_UPCALL_ENTRY(task);
	task->fail(args->expr, args->file, args->line);
	}

	extern "C" CDECL void
	upcall_fail(char const *expr,
	char const *file,
	size_t line) {
	rust_task *task = rust_try_get_current_task();
	if (task == NULL) {
	// FIXME #5161: Need to think about what to do here
	printf("failure outside of a task");
	abort();
	}
	s_fail_args args = {task,expr,file,line};
	UPCALL_SWITCH_STACK(task, &args, upcall_s_fail);
	}

	// FIXME (#2861): Alias used by libcore/rt.rs to avoid naming conflicts with
	// autogenerated wrappers for upcall_fail. Remove this when we fully move away
	// away from the C upcall path.
	extern "C" CDECL void
	rust_upcall_fail(char const *expr,
	char const *file,
	size_t line) {
	upcall_fail(expr, file, line);
	}

	struct s_trace_args {
	rust_task *task;
	char const *msg;
	char const *file;
	size_t line;
	};

	/**********************************************************************
	* Allocate an object in the task-local heap.
	*/

	struct s_malloc_args {
	rust_task *task;
	uintptr_t retval;
	type_desc *td;
	uintptr_t size;
	};

	extern "C" CDECL void
	upcall_s_malloc(s_malloc_args *args) {
	rust_task *task = args->task;
	LOG_UPCALL_ENTRY(task);
	LOG(task, mem, "upcall malloc(0x%" PRIxPTR ")", args->td);

	rust_opaque_box *box = task->boxed.malloc(args->td, args->size);
	void *body = box_body(box);

	debug::maybe_track_origin(task, box);

	LOG(task, mem,
	"upcall malloc(0x%" PRIxPTR ") = box 0x%" PRIxPTR
	" with body 0x%" PRIxPTR,
	args->td, (uintptr_t)box, (uintptr_t)body);

	args->retval = (uintptr_t)box;
	}

	extern "C" CDECL uintptr_t
	upcall_malloc(type_desc *td, uintptr_t size) {
	rust_task *task = rust_get_current_task();
	s_malloc_args args = {task, 0, td, size};
	UPCALL_SWITCH_STACK(task, &args, upcall_s_malloc);
	return args.retval;
	}

	// FIXME (#2861): Alias used by libcore/rt.rs to avoid naming conflicts with
	// autogenerated wrappers for upcall_malloc. Remove this when we fully move
	// away away from the C upcall path.
	extern "C" CDECL uintptr_t
	rust_upcall_malloc(type_desc *td, uintptr_t size) {
	return upcall_malloc(td, size);
	}

	/**********************************************************************
	* Called whenever an object in the task-local heap is freed.
	*/

	struct s_free_args {
	rust_task *task;
	void *ptr;
	};

	extern "C" CDECL void
	upcall_s_free(s_free_args *args) {
	rust_task *task = args->task;
	LOG_UPCALL_ENTRY(task);

	rust_sched_loop *sched_loop = task->sched_loop;
	DLOG(sched_loop, mem,
	"upcall free(0x%" PRIxPTR ", is_gc=%" PRIdPTR ")",
	(uintptr_t)args->ptr);

	debug::maybe_untrack_origin(task, args->ptr);

	rust_opaque_box box = (rust_opaque_box) args->ptr;
	task->boxed.free(box);
	}

	extern "C" CDECL void
	upcall_free(void* ptr) {
	rust_task *task = rust_get_current_task();
	s_free_args args = {task,ptr};
	UPCALL_SWITCH_STACK(task, &args, upcall_s_free);
	}

	// FIXME (#2861): Alias used by libcore/rt.rs to avoid naming conflicts with
	// autogenerated wrappers for upcall_free. Remove this when we fully move away
	// away from the C upcall path.
	extern "C" CDECL void
	rust_upcall_free(void* ptr) {
	upcall_free(ptr);
	}

	/**********************************************************************/

	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};
	rust_task *task = rust_get_current_task();

	// The personality function is run on the stack of the
	// last function that threw or landed, which is going
	// to sometimes be the C stack. If we're on the Rust stack
	// then switch to the C stack.

	if (task->on_rust_stack()) {
	UPCALL_SWITCH_STACK(task, &args, upcall_s_rust_personality);
	} else {
	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) {
	rust_task *task = rust_get_current_task();
	return task->next_stack(stk_sz,
	args_addr,
	args_sz);
	}

	// NB: This needs to be blazing fast. Don't switch stacks
	extern "C" CDECL void
	upcall_del_stack() {
	rust_task *task = rust_get_current_task();
	task->prev_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() {
	rust_task *task = rust_get_current_task();
	task->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:
	//