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mirror of https://github.com/janet-lang/janet synced 2024-11-15 13:14:48 +00:00
janet/core/fiber.c
Calvin Rose d84cc5342e Fix write after free bug.
Remove caching from strings, tuples, and structs.
Keyword style strings removed, now are just symbols. The
compiler can decide to treat symbols with a leading ':'
differently for mostly the same effect. This was done because
as strings are no longer interned, symbols are cheaper to look
up and check for equality.
2017-11-27 14:03:34 -05:00

275 lines
8.8 KiB
C

/*
* Copyright (c) 2017 Calvin Rose
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#include <dst/dst.h>
/* Initialize a new fiber */
DstFiber *dst_fiber(uint32_t capacity) {
DstFiber *fiber = dst_alloc(DST_MEMORY_FIBER, sizeof(DstFiber));
fiber->capacity = capacity;
if (capacity) {
DstValue *data = malloc(sizeof(DstValue) * capacity);
if (NULL == data) {
DST_OUT_OF_MEMORY;
}
fiber->data = data;
} else {
fiber->data = NULL;
}
fiber->parent = NULL;
return dst_fiber_reset(fiber);
}
/* Clear a fiber (reset it) */
DstFiber *dst_fiber_reset(DstFiber *fiber) {
fiber->frame = 0;
fiber->frametop = 0;
fiber->stacktop = DST_FRAME_SIZE;
fiber->status = DST_FIBER_DEAD;
fiber->parent = NULL;
fiber->ret = dst_wrap_nil();
return fiber;
}
/* Ensure that the fiber has enough extra capacity */
void dst_fiber_setcapacity(DstFiber *fiber, uint32_t n) {
DstValue *newData = realloc(fiber->data, sizeof(DstValue) * n);
if (NULL == newData) {
DST_OUT_OF_MEMORY;
}
fiber->data = newData;
fiber->capacity = n;
}
/* Push a value on the next stack frame */
void dst_fiber_push(DstFiber *fiber, DstValue x) {
if (fiber->stacktop >= fiber->capacity) {
dst_fiber_setcapacity(fiber, 2 * fiber->stacktop);
}
fiber->data[fiber->stacktop++] = x;
}
/* Push 2 values on the next stack frame */
void dst_fiber_push2(DstFiber *fiber, DstValue x, DstValue y) {
uint32_t newtop = fiber->stacktop + 2;
if (newtop > fiber->capacity) {
dst_fiber_setcapacity(fiber, 2 * newtop);
}
fiber->data[fiber->stacktop] = x;
fiber->data[fiber->stacktop + 1] = y;
fiber->stacktop = newtop;
}
/* Push 3 values on the next stack frame */
void dst_fiber_push3(DstFiber *fiber, DstValue x, DstValue y, DstValue z) {
uint32_t newtop = fiber->stacktop + 3;
if (newtop > fiber->capacity) {
dst_fiber_setcapacity(fiber, 2 * newtop);
}
fiber->data[fiber->stacktop] = x;
fiber->data[fiber->stacktop + 1] = y;
fiber->data[fiber->stacktop + 2] = z;
fiber->stacktop = newtop;
}
/* Push an array on the next stack frame */
void dst_fiber_pushn(DstFiber *fiber, const DstValue *arr, uint32_t n) {
uint32_t newtop = fiber->stacktop + n;
if (newtop > fiber->capacity) {
dst_fiber_setcapacity(fiber, 2 * newtop);
}
memcpy(fiber->data + fiber->stacktop, arr, n * sizeof(DstValue));
fiber->stacktop = newtop;
}
/* Pop a value off of the stack. Will not destroy a current stack frame.
* If there is nothing to pop of of the stack, return nil. */
DstValue dst_fiber_popvalue(DstFiber *fiber) {
uint32_t newstacktop = fiber->stacktop - 1;
if (newstacktop < fiber->frametop + DST_FRAME_SIZE) {
return dst_wrap_nil();
}
fiber->stacktop = newstacktop;
return fiber->data[newstacktop];
}
/* Push a stack frame to a fiber */
void dst_fiber_funcframe(DstFiber *fiber, DstFunction *func) {
DstStackFrame *newframe;
uint32_t i;
uint32_t oldframe = fiber->frame;
uint32_t nextframe = fiber->frametop + DST_FRAME_SIZE;
uint32_t nextframetop = nextframe + func->def->slotcount;
uint32_t nextstacktop = nextframetop + DST_FRAME_SIZE;
if (fiber->capacity < nextstacktop) {
dst_fiber_setcapacity(fiber, 2 * nextstacktop);
}
/* Set the next frame */
fiber->frame = nextframe;
fiber->frametop = nextframetop;
newframe = dst_fiber_frame(fiber);
/* Set up the new frame */
newframe->prevframe = oldframe;
newframe->pc = func->def->bytecode;
newframe->func = func;
/* Nil unset locals (Needed for gc correctness) */
for (i = fiber->stacktop; i < fiber->frametop; ++i) {
fiber->data[i].type = DST_NIL;
}
/* Check varargs */
if (func->def->flags & DST_FUNCDEF_FLAG_VARARG) {
uint32_t tuplehead = fiber->frame + func->def->arity;
if (tuplehead >= fiber->stacktop) {
fiber->data[tuplehead] = dst_wrap_tuple(dst_tuple_n(NULL, 0));
} else {
fiber->data[tuplehead] = dst_wrap_tuple(dst_tuple_n(
fiber->data + tuplehead,
fiber->stacktop - tuplehead));
}
}
/* Set stack top */
fiber->stacktop = nextstacktop;
}
/* Create a tail frame for a function */
void dst_fiber_funcframe_tail(DstFiber *fiber, DstFunction *func) {
uint32_t i;
uint32_t nextframetop = fiber->frame + func->def->slotcount;
uint32_t nextstacktop = nextframetop + DST_FRAME_SIZE;
uint32_t size = (fiber->stacktop - fiber->frametop) - DST_FRAME_SIZE;
uint32_t argtop = fiber->frame + size;
if (fiber->capacity < nextstacktop) {
dst_fiber_setcapacity(fiber, 2 * nextstacktop);
}
DstValue *stack = fiber->data + fiber->frame;
DstValue *args = fiber->data + fiber->frametop + DST_FRAME_SIZE;
/* Detatch old function */
if (NULL != dst_fiber_frame(fiber)->func)
dst_function_detach(dst_fiber_frame(fiber)->func);
memmove(stack, args, size * sizeof(DstValue));
/* Set stack stuff */
fiber->stacktop = nextstacktop;
fiber->frametop = nextframetop;
/* Nil unset locals (Needed for gc correctness) */
for (i = fiber->frame + size; i < fiber->frametop; ++i) {
fiber->data[i].type = DST_NIL;
}
/* Check varargs */
if (func->def->flags & DST_FUNCDEF_FLAG_VARARG) {
uint32_t tuplehead = fiber->frame + func->def->arity;
if (tuplehead >= argtop) {
fiber->data[tuplehead] = dst_wrap_tuple(dst_tuple_n(NULL, 0));
} else {
fiber->data[tuplehead] = dst_wrap_tuple(dst_tuple_n(
fiber->data + tuplehead,
argtop - tuplehead));
}
}
/* Set frame stuff */
dst_fiber_frame(fiber)->func = func;
dst_fiber_frame(fiber)->pc = func->def->bytecode;
}
/* Push a stack frame to a fiber for a c function */
void dst_fiber_cframe(DstFiber *fiber) {
DstStackFrame *newframe;
uint32_t oldframe = fiber->frame;
uint32_t nextframe = fiber->frametop + DST_FRAME_SIZE;
uint32_t nextframetop = fiber->stacktop;
uint32_t nextstacktop = nextframetop + DST_FRAME_SIZE;
if (fiber->capacity < nextstacktop) {
dst_fiber_setcapacity(fiber, 2 * nextstacktop);
}
/* Set the next frame */
fiber->frame = nextframe;
fiber->frametop = nextframetop;
fiber->stacktop = nextstacktop;
newframe = dst_fiber_frame(fiber);
/* Set up the new frame */
newframe->prevframe = oldframe;
newframe->pc = NULL;
newframe->func = NULL;
}
/* Create a cframe for a tail call */
void dst_fiber_cframe_tail(DstFiber *fiber) {
uint32_t size = (fiber->stacktop - fiber->frametop) - DST_FRAME_SIZE;
uint32_t nextframetop = fiber->frame + size;;
uint32_t nextstacktop = nextframetop + DST_FRAME_SIZE;
if (fiber->frame == 0) {
return dst_fiber_cframe(fiber);
}
DstValue *stack = fiber->data + fiber->frame;
DstValue *args = fiber->data + fiber->frametop + DST_FRAME_SIZE;
/* Detach old function */
if (NULL != dst_fiber_frame(fiber)->func)
dst_function_detach(dst_fiber_frame(fiber)->func);
/* Copy pushed args to frame */
memmove(stack, args, size * sizeof(DstValue));
/* Set the next frame */
fiber->frametop = nextframetop;
fiber->stacktop = nextstacktop;
/* Set up the new frame */
dst_fiber_frame(fiber)->func = NULL;
dst_fiber_frame(fiber)->pc = NULL;
}
/* Pop a stack frame from the fiber. Returns the new stack frame, or
* NULL if there are no more frames */
void dst_fiber_popframe(DstFiber *fiber) {
DstStackFrame *frame = dst_fiber_frame(fiber);
/* Clean up the frame (detach environments) */
if (NULL != frame->func)
dst_function_detach(frame->func);
/* Shrink stack */
fiber->stacktop = fiber->frame;
fiber->frametop = fiber->frame - DST_FRAME_SIZE;
fiber->frame = frame->prevframe;
}