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vm.c
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/*
* Copyright (C) 2020-2021 Jo-Philipp Wich <[email protected]>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <stdarg.h>
#include <string.h>
#include <assert.h>
#include <ctype.h>
#include <math.h>
#include <errno.h>
#include <limits.h>
#include <fcntl.h>
#include <unistd.h>
#include "ucode/vm.h"
#include "ucode/compiler.h"
#include "ucode/program.h"
#include "ucode/lib.h" /* uc_error_context_format() */
#include "ucode/platform.h"
#undef __insn
#define __insn(_name) #_name,
static const char *insn_names[__I_MAX] = {
__insns
};
static const int8_t insn_operand_bytes[__I_MAX] = {
[I_LOAD] = 4,
[I_LOAD8] = 1,
[I_LOAD16] = 2,
[I_LOAD32] = 4,
[I_LREXP] = 4,
[I_LLOC] = 4,
[I_LVAR] = 4,
[I_LUPV] = 4,
[I_CLFN] = 4,
[I_ARFN] = 4,
[I_SLOC] = 4,
[I_SUPV] = 4,
[I_SVAR] = 4,
[I_ULOC] = 4,
[I_UUPV] = 4,
[I_UVAR] = 4,
[I_UVAL] = 1,
[I_NARR] = 4,
[I_PARR] = 4,
[I_NOBJ] = 4,
[I_SOBJ] = 4,
[I_JMP] = -4,
[I_JMPZ] = -4,
[I_COPY] = 1,
[I_CALL] = 4,
[I_MCALL] = 4,
[I_QCALL] = 4,
[I_QMCALL] = 4,
[I_IMPORT] = 4,
[I_EXPORT] = 4,
[I_DYNLOAD] = 4
};
static const char *exception_type_strings[] = {
[EXCEPTION_SYNTAX] = "Syntax error",
[EXCEPTION_RUNTIME] = "Runtime error",
[EXCEPTION_TYPE] = "Type error",
[EXCEPTION_REFERENCE] = "Reference error",
[EXCEPTION_USER] = "Error",
[EXCEPTION_EXIT] = "Exit"
};
static void
uc_vm_reset_stack(uc_vm_t *vm)
{
while (vm->stack.count > 0) {
vm->stack.count--;
ucv_put(vm->stack.entries[vm->stack.count]);
vm->stack.entries[vm->stack.count] = NULL;
}
}
static uc_value_t *
uc_vm_callframe_pop(uc_vm_t *vm);
static void
uc_vm_reset_callframes(uc_vm_t *vm)
{
while (vm->callframes.count > 0)
ucv_put(uc_vm_callframe_pop(vm));
}
static uc_value_t *
uc_vm_alloc_global_scope(uc_vm_t *vm)
{
uc_value_t *scope, *arr;
size_t i;
scope = ucv_object_new(vm);
/* build default require() search path */
arr = ucv_array_new(vm);
for (i = 0; i < vm->config->module_search_path.count; i++)
ucv_array_push(arr, ucv_string_new(vm->config->module_search_path.entries[i]));
/* register module related constants */
ucv_object_add(scope, "REQUIRE_SEARCH_PATH", arr);
ucv_object_add(scope, "modules", ucv_object_new(vm));
/* register scope math constants */
ucv_object_add(scope, "NaN", ucv_double_new(NAN));
ucv_object_add(scope, "Infinity", ucv_double_new(INFINITY));
/* register global property */
ucv_object_add(scope, "global", ucv_get(scope));
uc_vm_scope_set(vm, scope);
return scope;
}
static void
uc_vm_output_exception(uc_vm_t *vm, uc_exception_t *ex);
static void
uc_vm_signal_handler(int sig)
{
uc_vm_t *vm = uc_thread_context_get()->signal_handler_vm;
assert(vm);
uc_vm_signal_raise(vm, sig);
}
static void
uc_vm_signal_handlers_setup(uc_vm_t *vm)
{
uc_thread_context_t *tctx;
memset(&vm->signal, 0, sizeof(vm->signal));
vm->signal.sigpipe[0] = -1;
vm->signal.sigpipe[1] = -1;
if (!vm->config->setup_signal_handlers)
return;
tctx = uc_thread_context_get();
if (tctx->signal_handler_vm)
return;
if (pipe2(vm->signal.sigpipe, O_CLOEXEC | O_NONBLOCK) != 0)
return;
vm->signal.handler = ucv_array_new_length(vm, UC_SYSTEM_SIGNAL_COUNT);
vm->signal.sa.sa_handler = uc_vm_signal_handler;
vm->signal.sa.sa_flags = SA_RESTART | SA_ONSTACK;
sigemptyset(&vm->signal.sa.sa_mask);
tctx->signal_handler_vm = vm;
}
static void
uc_vm_signal_handlers_reset(uc_vm_t *vm)
{
uc_thread_context_t *tctx = uc_thread_context_get();
struct sigaction sa = { 0 };
size_t i, signo;
if (vm != tctx->signal_handler_vm)
return;
sa.sa_handler = SIG_DFL;
sigemptyset(&sa.sa_mask);
for (signo = 0; signo < ucv_array_length(vm->signal.handler); signo++)
if (ucv_is_callable(ucv_array_get(vm->signal.handler, signo)))
sigaction(signo, &sa, NULL);
for (i = 0; i < ARRAY_SIZE(vm->signal.sigpipe); i++) {
if (vm->signal.sigpipe[i] > STDERR_FILENO)
close(vm->signal.sigpipe[i]);
vm->signal.sigpipe[i] = -1;
}
tctx->signal_handler_vm = NULL;
}
void uc_vm_init(uc_vm_t *vm, uc_parse_config_t *config)
{
vm->exception.type = EXCEPTION_NONE;
vm->exception.message = NULL;
vm->config = config ? config : &uc_default_parse_config;
vm->open_upvals = NULL;
vm->values.prev = &vm->values;
vm->values.next = &vm->values;
vm->strbuf = NULL;
vm->output = stdout;
uc_vm_reset_stack(vm);
uc_vm_alloc_global_scope(vm);
uc_vm_exception_handler_set(vm, uc_vm_output_exception);
uc_vm_trace_set(vm, 0);
uc_vm_signal_handlers_setup(vm);
}
void uc_vm_free(uc_vm_t *vm)
{
uc_upvalref_t *ref;
size_t i;
uc_vm_signal_handlers_reset(vm);
ucv_put(vm->exception.stacktrace);
free(vm->exception.message);
while (vm->open_upvals) {
ref = vm->open_upvals->next;
ucv_put(&vm->open_upvals->header);
vm->open_upvals = ref;
}
for (i = 0; i < vm->restypes.count; i++)
ucv_put(vm->restypes.entries[i]->proto);
uc_vm_reset_callframes(vm);
uc_vm_reset_stack(vm);
uc_vector_clear(&vm->stack);
uc_vector_clear(&vm->callframes);
printbuf_free(vm->strbuf);
ucv_freeall(vm);
for (i = 0; i < vm->restypes.count; i++)
free(vm->restypes.entries[i]);
uc_vector_clear(&vm->restypes);
}
static uc_chunk_t *
uc_vm_frame_chunk(uc_callframe_t *frame)
{
return frame->closure ? &frame->closure->function->chunk : NULL;
}
static uc_program_t *
uc_vm_frame_program(uc_callframe_t *frame)
{
return frame->closure ? frame->closure->function->program : NULL;
}
static uc_source_t *
uc_vm_frame_source(uc_callframe_t *frame)
{
return frame->closure ? uc_program_function_source(frame->closure->function) : NULL;
}
static uc_callframe_t *
uc_vm_current_frame(uc_vm_t *vm)
{
return uc_vector_last(&vm->callframes);
}
static uc_program_t *
uc_vm_current_program(uc_vm_t *vm)
{
return uc_vm_frame_program(uc_vm_current_frame(vm));
}
static bool
uc_vm_is_strict(uc_vm_t *vm)
{
return uc_vm_current_frame(vm)->strict;
}
static uc_vm_insn_t
uc_vm_decode_insn(uc_vm_t *vm, uc_callframe_t *frame, uc_chunk_t *chunk)
{
uc_vm_insn_t insn;
#ifndef NDEBUG
uint8_t *end = chunk->entries + chunk->count;
#endif
assert(frame->ip < end);
insn = frame->ip[0];
frame->ip++;
assert(frame->ip + abs(insn_operand_bytes[insn]) <= end);
switch (insn_operand_bytes[insn]) {
case 0:
break;
case -4:
vm->arg.s32 = (
frame->ip[0] * 0x1000000UL +
frame->ip[1] * 0x10000UL +
frame->ip[2] * 0x100UL +
frame->ip[3]
) - 0x7fffffff;
frame->ip += 4;
break;
case 1:
vm->arg.u8 = frame->ip[0];
frame->ip++;
break;
case 2:
vm->arg.u16 = (
frame->ip[0] * 0x100 +
frame->ip[1]
);
frame->ip += 2;
break;
case 4:
vm->arg.u32 = (
frame->ip[0] * 0x1000000UL +
frame->ip[1] * 0x10000UL +
frame->ip[2] * 0x100UL +
frame->ip[3]
);
frame->ip += 4;
break;
default:
fprintf(stderr, "Unhandled operand format: %" PRId8 "\n", insn_operand_bytes[insn]);
abort();
}
return insn;
}
static char *
uc_vm_format_val(uc_vm_t *vm, uc_value_t *val)
{
if (!vm->strbuf)
vm->strbuf = xprintbuf_new();
else
printbuf_reset(vm->strbuf);
ucv_to_stringbuf(NULL, vm->strbuf, val, true);
if (printbuf_length(vm->strbuf) >= 64) {
printbuf_memset(vm->strbuf, 60, '.', 3);
printbuf_memset(vm->strbuf, 63, 0, 1);
}
return vm->strbuf->buf;
}
static void
uc_vm_frame_dump(uc_vm_t *vm, uc_callframe_t *frame)
{
uc_chunk_t *chunk = uc_vm_frame_chunk(frame);
uc_function_t *function;
uc_closure_t *closure;
uc_upvalref_t *ref;
uc_value_t *v;
size_t i;
fprintf(stderr, " [*] CALLFRAME[%zx]\n",
frame - vm->callframes.entries);
fprintf(stderr, " |- stackframe %zu/%zu\n",
frame->stackframe, vm->stack.count);
fprintf(stderr, " |- ctx %s\n",
uc_vm_format_val(vm, frame->ctx));
if (chunk) {
closure = frame->closure;
function = closure->function;
fprintf(stderr, " `- %zu upvalues\n",
function->nupvals);
for (i = 0; i < function->nupvals; i++) {
ref = closure->upvals[i];
v = uc_chunk_debug_get_variable(chunk, 0, i, true);
fprintf(stderr, " [%zu] <%p> %s ",
i, (void *)ref, uc_vm_format_val(vm, v));
if (!ref) {
fprintf(stderr, "{unresolved}\n");
}
else if (ref->closed) {
fprintf(stderr, "{closed} %s\n",
uc_vm_format_val(vm, ref->value));
}
else {
fprintf(stderr, "{open[%zu]} %s\n",
ref->slot,
uc_vm_format_val(vm, vm->stack.entries[ref->slot]));
}
ucv_put(v);
}
}
}
static uc_value_t *
uc_vm_resolve_upval(uc_vm_t *vm, uc_value_t *value)
{
uc_upvalref_t *ref;
#ifdef __clang_analyzer__
/* Clang static analyzer does not understand that ucv_type(NULL) can't
* possibly yield UC_UPVALUE. Nudge it. */
if (value != NULL && ucv_type(value) == UC_UPVALUE)
#else
if (ucv_type(value) == UC_UPVALUE)
#endif
{
ref = (uc_upvalref_t *)value;
if (ref->closed)
return ucv_get(ref->value);
else
return ucv_get(vm->stack.entries[ref->slot]);
}
return value;
}
void
uc_vm_stack_push(uc_vm_t *vm, uc_value_t *value)
{
uc_vector_push(&vm->stack, uc_vm_resolve_upval(vm, value));
if (vm->trace) {
fprintf(stderr, " [+%zd] %s\n",
vm->stack.count - 1,
uc_vm_format_val(vm, vm->stack.entries[vm->stack.count - 1]));
}
}
uc_value_t *
uc_vm_stack_pop(uc_vm_t *vm)
{
uc_value_t *rv;
vm->stack.count--;
rv = vm->stack.entries[vm->stack.count];
vm->stack.entries[vm->stack.count] = NULL;
if (vm->trace) {
fprintf(stderr, " [-%zd] %s\n",
vm->stack.count,
uc_vm_format_val(vm, rv));
}
return rv;
}
uc_value_t *
uc_vm_stack_peek(uc_vm_t *vm, size_t offset)
{
return vm->stack.entries[vm->stack.count + (-1 - offset)];
}
static void
uc_vm_stack_set(uc_vm_t *vm, size_t offset, uc_value_t *value)
{
if (vm->trace) {
fprintf(stderr, " [!%zu] %s\n",
offset,
uc_vm_format_val(vm, value));
}
ucv_put(vm->stack.entries[offset]);
vm->stack.entries[offset] = value;
}
static void
uc_vm_call_native(uc_vm_t *vm, uc_value_t *ctx, uc_cfunction_t *fptr, bool mcall, size_t nargs)
{
uc_value_t *res = NULL;
uc_callframe_t *frame;
/* add new callframe */
frame = uc_vector_push(&vm->callframes, {
.stackframe = vm->stack.count - nargs - 1,
.cfunction = fptr,
.closure = NULL,
.ctx = ctx,
.mcall = mcall
});
if (vm->trace)
uc_vm_frame_dump(vm, frame);
res = fptr->cfn(vm, nargs);
/* Reset stack, check for callframe depth since an uncatched exception in managed
* code executed by fptr->cfn() could've reset the callframe stack already. */
if (vm->callframes.count > 0)
ucv_put(uc_vm_callframe_pop(vm));
/* push return value */
if (!vm->exception.type)
uc_vm_stack_push(vm, res);
else
ucv_put(res);
}
static bool
uc_vm_call_function(uc_vm_t *vm, uc_value_t *ctx, uc_value_t *fno, bool mcall, size_t argspec)
{
size_t i, j, stackoff, nargs = argspec & 0xffff, nspreads = argspec >> 16;
uc_callframe_t *frame = NULL;
uc_value_t *ellip, *arg;
uc_function_t *function;
uc_closure_t *closure;
uint16_t slot, tmp;
char *s;
/* XXX: make dependent on stack size */
if (vm->callframes.count >= 1000) {
uc_vm_raise_exception(vm, EXCEPTION_RUNTIME, "Too much recursion");
ucv_put(ctx);
ucv_put(fno);
return false;
}
stackoff = vm->stack.count - nargs - 1;
/* argument list contains spread operations, we need to reshuffle the stack */
if (nspreads > 0) {
frame = uc_vm_current_frame(vm);
/* create temporary array */
ellip = ucv_array_new_length(vm, nargs);
/* pop original stack values and push to temp array in reverse order */
for (i = 0; i < nargs; i++)
ucv_array_push(ellip, uc_vm_stack_pop(vm));
/* for each spread value index ... */
for (i = 0, slot = nargs; i < nspreads; i++) {
/* decode stack depth value */
tmp = frame->ip[0] * 0x100 + frame->ip[1];
frame->ip += 2;
/* push each preceeding non-spread value to the stack */
for (j = slot; j > tmp + 1UL; j--)
uc_vm_stack_push(vm, ucv_get(ucv_array_get(ellip, j - 1)));
/* read spread value at index... */
slot = tmp;
arg = ucv_get(ucv_array_get(ellip, slot));
/* ... ensure that it is an array type ... */
if (ucv_type(arg) != UC_ARRAY) {
s = ucv_to_string(vm, arg);
uc_vm_raise_exception(vm, EXCEPTION_TYPE, "(%s) is not iterable", s);
free(s);
ucv_put(ctx);
ucv_put(fno);
ucv_put(ellip);
return false;
}
/* ... and push each spread array value as argument to the stack */
for (j = 0; j < ucv_array_length(arg); j++)
uc_vm_stack_push(vm, ucv_get(ucv_array_get(arg, j)));
ucv_put(arg);
}
/* push remaining non-spread arguments to the stack */
for (i = slot; i > 0; i--)
uc_vm_stack_push(vm, ucv_get(ucv_array_get(ellip, i - 1)));
/* free temp array */
ucv_put(ellip);
/* update arg count */
nargs = vm->stack.count - stackoff - 1;
}
/* is a native function */
if (ucv_type(fno) == UC_CFUNCTION) {
uc_vm_call_native(vm, ctx, (uc_cfunction_t *)fno, mcall, nargs);
return true;
}
if (ucv_type(fno) != UC_CLOSURE) {
uc_vm_raise_exception(vm, EXCEPTION_TYPE, "left-hand side is not a function");
ucv_put(ctx);
ucv_put(fno);
return false;
}
closure = (uc_closure_t *)fno;
function = closure->function;
/* fewer arguments on stack than function expects => pad */
if (nargs < function->nargs) {
for (i = nargs; i < function->nargs; i++) {
if (function->vararg && (i + 1) == function->nargs)
uc_vm_stack_push(vm, ucv_array_new_length(vm, 0));
else
uc_vm_stack_push(vm, NULL);
}
}
/* more arguments on stack than function expects... */
else if (nargs > function->nargs - function->vararg) {
/* is a vararg function => pass excess args as array */
if (function->vararg) {
ellip = ucv_array_new_length(vm, nargs - (function->nargs - 1));
for (i = function->nargs; i <= nargs; i++)
ucv_array_push(ellip, uc_vm_stack_peek(vm, nargs - i));
for (i = function->nargs; i <= nargs; i++)
uc_vm_stack_pop(vm);
uc_vm_stack_push(vm, ellip);
}
/* static amount of args => drop excess values */
else {
for (i = function->nargs; i < nargs; i++)
ucv_put(uc_vm_stack_pop(vm));
}
}
frame = uc_vector_push(&vm->callframes, {
.stackframe = stackoff,
.cfunction = NULL,
.closure = closure,
.ctx = ctx,
.ip = function->chunk.entries,
.mcall = mcall,
.strict = function->strict
});
if (vm->trace)
uc_vm_frame_dump(vm, frame);
return true;
}
static uc_source_t *last_source = NULL;
static size_t last_srcpos = 0;
static void
uc_dump_insn(uc_vm_t *vm, uint8_t *pos, uc_vm_insn_t insn)
{
uc_callframe_t *frame = uc_vm_current_frame(vm);
uc_chunk_t *chunk = uc_vm_frame_chunk(frame);
uc_stringbuf_t *buf = NULL;
uc_value_t *cnst = NULL;
uc_source_t *source;
size_t srcpos;
srcpos = uc_program_function_srcpos(frame->closure->function, pos - chunk->entries);
source = uc_vm_frame_source(frame);
if (last_srcpos == 0 || last_source != source || srcpos != last_srcpos) {
buf = xprintbuf_new();
uc_source_context_format(buf, source, srcpos, true);
fwrite(buf->buf, 1, printbuf_length(buf), stderr);
printbuf_free(buf);
last_source = source;
last_srcpos = srcpos;
}
fprintf(stderr, "%08zx %s", pos - chunk->entries, insn_names[insn]);
switch (insn_operand_bytes[insn]) {
case 0:
break;
case -1:
fprintf(stderr, " {%s%hhd}", vm->arg.s8 < 0 ? "" : "+", vm->arg.s8);
break;
case -2:
fprintf(stderr, " {%c0x%hx}",
vm->arg.s16 < 0 ? '-' : '+',
(uint16_t)(vm->arg.s16 < 0 ? -vm->arg.s16 : vm->arg.s16));
break;
case -4:
fprintf(stderr, " {%c0x%x}",
vm->arg.s32 < 0 ? '-' : '+',
(uint32_t)(vm->arg.s32 < 0 ? -vm->arg.s32 : vm->arg.s32));
break;
case 1:
fprintf(stderr, " {%hhu}", vm->arg.u8);
break;
case 2:
fprintf(stderr, " {0x%hx}", vm->arg.u16);
break;
case 4:
fprintf(stderr, " {0x%x}", vm->arg.u32);
break;
default:
fprintf(stderr, " (unknown operand format: %" PRId8 ")", insn_operand_bytes[insn]);
break;
}
switch (insn) {
case I_LOAD:
case I_LVAR:
case I_SVAR:
cnst = uc_program_get_constant(uc_vm_frame_program(uc_vector_last(&vm->callframes)), vm->arg.u32);
fprintf(stderr, "\t; %s",
cnst ? uc_vm_format_val(vm, cnst) : "(?)");
ucv_put(cnst);
break;
case I_LLOC:
case I_LUPV:
case I_SLOC:
case I_SUPV:
cnst = uc_chunk_debug_get_variable(chunk, pos - chunk->entries, vm->arg.u32, (insn == I_LUPV || insn == I_SUPV));
fprintf(stderr, "\t; %s",
cnst ? uc_vm_format_val(vm, cnst) : "(?)");
ucv_put(cnst);
break;
case I_ULOC:
case I_UUPV:
cnst = uc_chunk_debug_get_variable(chunk, pos - chunk->entries, vm->arg.u32 & 0x00ffffff, (insn == I_UUPV));
/* fall through */
case I_UVAR:
if (!cnst)
cnst = uc_program_get_constant(uc_vm_frame_program(uc_vector_last(&vm->callframes)), vm->arg.u32 & 0x00ffffff);
fprintf(stderr, "\t; %s (%s)",
cnst ? uc_vm_format_val(vm, cnst) : "(?)",
insn_names[vm->arg.u32 >> 24]);
ucv_put(cnst);
break;
case I_UVAL:
fprintf(stderr, "\t; (%s)", insn_names[vm->arg.u32]);
break;
default:
break;
}
fprintf(stderr, "\n");
}
static uc_value_t *
uc_vm_exception_tostring(uc_vm_t *vm, size_t nargs)
{
uc_callframe_t *frame = uc_vm_current_frame(vm);
uc_value_t *message = ucv_object_get(frame->ctx, "message", NULL);
return message ? ucv_get(message) : ucv_string_new("Exception");
}
static uc_value_t *
uc_vm_exception_new(uc_vm_t *vm, uc_exception_type_t type, const char *message, uc_value_t *stacktrace)
{
uc_value_t *exception_prototype = uc_vm_registry_get(vm, "vm.exception.proto");
uc_value_t *exo;
if (exception_prototype == NULL) {
exception_prototype = ucv_object_new(vm);
ucv_object_add(exception_prototype, "tostring",
ucv_cfunction_new("tostring", uc_vm_exception_tostring));
uc_vm_registry_set(vm, "vm.exception.proto", exception_prototype);
}
exo = ucv_object_new(vm);
ucv_object_add(exo, "type", ucv_string_new(exception_type_strings[type]));
ucv_object_add(exo, "message", ucv_string_new(message));
ucv_object_add(exo, "stacktrace", ucv_get(stacktrace));
ucv_prototype_set(exo, ucv_get(exception_prototype));
return exo;
}
static void
uc_vm_clear_exception(uc_vm_t *vm)
{
vm->exception.type = EXCEPTION_NONE;
ucv_put(vm->exception.stacktrace);
vm->exception.stacktrace = NULL;
free(vm->exception.message);
vm->exception.message = NULL;
}
static bool
uc_vm_handle_exception(uc_vm_t *vm)
{
uc_callframe_t *frame = NULL;
uc_chunk_t *chunk = NULL;
uc_value_t *exo;
size_t i, pos;
if (vm->callframes.count)
frame = uc_vm_current_frame(vm);
if (!frame || !frame->closure)
return false;
chunk = uc_vm_frame_chunk(frame);
pos = frame->ip - chunk->entries;
/* iterate the known exception ranges, see if the current ip falls into any of them */
for (i = 0; i < chunk->ehranges.count; i++) {
/* skip nonmatching ranges */
if (pos < chunk->ehranges.entries[i].from ||
pos >= chunk->ehranges.entries[i].to)
continue;
/* we found a matching range... first unwind stack */
while (vm->stack.count > frame->stackframe + chunk->ehranges.entries[i].slot)
ucv_put(uc_vm_stack_pop(vm));
/* prepare exception object and expose it to user handler code */
exo = uc_vm_exception_new(vm, vm->exception.type, vm->exception.message, vm->exception.stacktrace);
uc_vm_stack_push(vm, exo);
/* reset exception information */
uc_vm_clear_exception(vm);
/* jump to exception handler */
if (chunk->ehranges.entries[i].target >= chunk->count) {
uc_vm_raise_exception(vm, EXCEPTION_RUNTIME, "jump target out of range");
return false;
}
#if 0
if (vm->trace && chunk->entries + chunk->ehranges.entries[i].target > frame->ip) {
while (frame->ip < chunk->entries + chunk->ehranges.entries[i].target) {
fprintf(stderr, "(eh:skip) [%p:%zu] ", chunk, frame->ip - chunk->entries);
uc_dump_insn(vm, frame->ip, uc_vm_decode_insn(vm, frame, chunk));
}
}
#endif
frame->ip = chunk->entries + chunk->ehranges.entries[i].target;
return true;
}
return false;
}
static uc_value_t *
uc_vm_capture_stacktrace(uc_vm_t *vm, size_t i)
{
uc_value_t *stacktrace, *entry, *last = NULL;
uc_function_t *function;
uc_callframe_t *frame;
uc_source_t *source;
size_t off, srcpos;
char *name;
stacktrace = ucv_array_new(vm);
for (; i > 0; i--) {
frame = &vm->callframes.entries[i - 1];
entry = ucv_object_new(vm);
if (frame->closure) {
function = frame->closure->function;
source = uc_program_function_source(function);
off = (frame->ip - uc_vm_frame_chunk(frame)->entries) - 1;
srcpos = uc_program_function_srcpos(function, off);
ucv_object_add(entry, "filename", ucv_string_new(source->filename));
ucv_object_add(entry, "line", ucv_int64_new(uc_source_get_line(source, &srcpos)));
ucv_object_add(entry, "byte", ucv_int64_new(srcpos));
}
if (i > 1) {
if (frame->closure) {
if (frame->closure->function->name[0])
name = frame->closure->function->name;
else if (frame->closure->is_arrow)
name = "[arrow function]";
else
name = "[anonymous function]";
}
else {
name = frame->cfunction->name;
}
ucv_object_add(entry, "function", ucv_string_new(name));
}
if (!ucv_is_equal(last, entry)) {
ucv_array_push(stacktrace, entry);
last = entry;
}
else {
ucv_put(entry);
}
}
return stacktrace;
}
static uc_value_t *
uc_vm_get_error_context(uc_vm_t *vm)
{
size_t offset, i, byte, line;
uc_value_t *stacktrace;
uc_callframe_t *frame;
uc_stringbuf_t *buf;
uc_chunk_t *chunk;
/* skip to first non-native function call frame */
for (i = vm->callframes.count; i > 1; i--)
if (vm->callframes.entries[i - 1].closure)
break;
frame = &vm->callframes.entries[i - 1];
if (!frame->closure)
return NULL;
chunk = uc_vm_frame_chunk(frame);
offset = uc_program_function_srcpos(frame->closure->function, (frame->ip - chunk->entries) - 1);
stacktrace = uc_vm_capture_stacktrace(vm, i);
buf = ucv_stringbuf_new();
byte = offset;
line = uc_source_get_line(uc_program_function_source(frame->closure->function), &byte);
if (line)
uc_error_context_format(buf, uc_vm_frame_source(frame), stacktrace, offset);
else if (frame->ip != chunk->entries)