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e7d37983c42e3783cebe3346d65b9b887e3bdbc8
jq/src/execute.c
T
Leonid S. Usov cf4b48c7ba Save literal value of the parsed number to preserve it for the output 
Extend jv_number to use decNumber for storing number literals. Any math
operations on the numbers will truncate them to double precision.
Comparisons when both numbers are literal numbers will compare them
without truncation.

Delay conversion of numbers to doubles until a math operation is performed,
to preserve precision. A literal jv_number will only need conversion to
double once, and will reuse the resultant double on subsequent
conversions.

Outputting literal jv_numbers preserves the original precision.

Add strong pthread requirement to manage contexts/allocations for
converting numbers between their decNumber, string, and double formats.
2019-10-22 14:11:04 -04:00

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#include <assert.h>
#include <errno.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <sys/stat.h>
#include "exec_stack.h"
#include "bytecode.h"
#include "jv_alloc.h"
#include "jq_parser.h"
#include "locfile.h"
#include "jv.h"
#include "jq.h"
#include "parser.h"
#include "builtin.h"
#include "util.h"
#include "linker.h"
struct jq_state {
void (*nomem_handler)(void *);
void *nomem_handler_data;
struct bytecode* bc;
jq_msg_cb err_cb;
void *err_cb_data;
jv error;
struct stack stk;
stack_ptr curr_frame;
stack_ptr stk_top;
stack_ptr fork_top;
jv path;
jv value_at_path;
int subexp_nest;
int debug_trace_enabled;
int initial_execution;
unsigned next_label;
int halted;
jv exit_code;
jv error_message;
jv attrs;
jq_input_cb input_cb;
void *input_cb_data;
jq_msg_cb debug_cb;
void *debug_cb_data;
};
struct closure {
struct bytecode* bc; // jq bytecode
stack_ptr env; // jq stack address of closed frame
};
// locals for any function called: either a closure or a local variable
union frame_entry {
struct closure closure;
jv localvar;
};
// jq function call frame
struct frame {
struct bytecode* bc; // jq bytecode for callee
stack_ptr env; // jq stack address of frame to return to
stack_ptr retdata; // jq stack address to unwind to on RET
uint16_t* retaddr; // jq bytecode return address
union frame_entry entries[]; // nclosures + nlocals
};
static int frame_size(struct bytecode* bc) {
return sizeof(struct frame) + sizeof(union frame_entry) * (bc->nclosures + bc->nlocals);
}
static struct frame* frame_current(struct jq_state* jq) {
struct frame* fp = stack_block(&jq->stk, jq->curr_frame);
stack_ptr next = *stack_block_next(&jq->stk, jq->curr_frame);
if (next) {
struct frame* fpnext = stack_block(&jq->stk, next);
struct bytecode* bc = fpnext->bc;
assert(fp->retaddr >= bc->code && fp->retaddr < bc->code + bc->codelen);
} else {
assert(fp->retaddr == 0);
}
return fp;
}
static stack_ptr frame_get_level(struct jq_state* jq, int level) {
stack_ptr fr = jq->curr_frame;
for (int i=0; i<level; i++) {
struct frame* fp = stack_block(&jq->stk, fr);
fr = fp->env;
}
return fr;
}
static jv* frame_local_var(struct jq_state* jq, int var, int level) {
struct frame* fr = stack_block(&jq->stk, frame_get_level(jq, level));
assert(var >= 0);
assert(var < fr->bc->nlocals);
return &fr->entries[fr->bc->nclosures + var].localvar;
}
static struct closure make_closure(struct jq_state* jq, uint16_t* pc) {
uint16_t level = *pc++;
uint16_t idx = *pc++;
stack_ptr fridx = frame_get_level(jq, level);
struct frame* fr = stack_block(&jq->stk, fridx);
if (idx & ARG_NEWCLOSURE) {
// A new closure closing the frame identified by level, and with
// the bytecode body of the idx'th subfunction of that frame
int subfn_idx = idx & ~ARG_NEWCLOSURE;
assert(subfn_idx < fr->bc->nsubfunctions);
struct closure cl = {fr->bc->subfunctions[subfn_idx],
fridx};
return cl;
} else {
// A reference to a closure from the frame identified by level; copy
// it as-is
int closure = idx;
assert(closure >= 0);
assert(closure < fr->bc->nclosures);
return fr->entries[closure].closure;
}
}
static struct frame* frame_push(struct jq_state* jq, struct closure callee,
uint16_t* argdef, int nargs) {
stack_ptr new_frame_idx = stack_push_block(&jq->stk, jq->curr_frame, frame_size(callee.bc));
struct frame* new_frame = stack_block(&jq->stk, new_frame_idx);
new_frame->bc = callee.bc;
new_frame->env = callee.env;
assert(nargs == new_frame->bc->nclosures);
union frame_entry* entries = new_frame->entries;
for (int i=0; i<nargs; i++) {
entries->closure = make_closure(jq, argdef + i * 2);
entries++;
}
for (int i=0; i<callee.bc->nlocals; i++) {
entries->localvar = jv_invalid();
entries++;
}
jq->curr_frame = new_frame_idx;
return new_frame;
}
static void frame_pop(struct jq_state* jq) {
assert(jq->curr_frame);
struct frame* fp = frame_current(jq);
if (stack_pop_will_free(&jq->stk, jq->curr_frame)) {
int nlocals = fp->bc->nlocals;
for (int i=0; i<nlocals; i++) {
jv_free(*frame_local_var(jq, i, 0));
}
}
jq->curr_frame = stack_pop_block(&jq->stk, jq->curr_frame, frame_size(fp->bc));
}
void stack_push(jq_state *jq, jv val) {
assert(jv_is_valid(val));
jq->stk_top = stack_push_block(&jq->stk, jq->stk_top, sizeof(jv));
jv* sval = stack_block(&jq->stk, jq->stk_top);
*sval = val;
}
jv stack_pop(jq_state *jq) {
jv* sval = stack_block(&jq->stk, jq->stk_top);
jv val = *sval;
if (!stack_pop_will_free(&jq->stk, jq->stk_top)) {
val = jv_copy(val);
}
jq->stk_top = stack_pop_block(&jq->stk, jq->stk_top, sizeof(jv));
assert(jv_is_valid(val));
return val;
}
// Like stack_pop(), but assert !stack_pop_will_free() and replace with
// jv_null() on the stack.
jv stack_popn(jq_state *jq) {
jv* sval = stack_block(&jq->stk, jq->stk_top);
jv val = *sval;
if (!stack_pop_will_free(&jq->stk, jq->stk_top)) {
*sval = jv_null();
}
jq->stk_top = stack_pop_block(&jq->stk, jq->stk_top, sizeof(jv));
assert(jv_is_valid(val));
return val;
}
struct forkpoint {
stack_ptr saved_data_stack;
stack_ptr saved_curr_frame;
int path_len, subexp_nest;
jv value_at_path;
uint16_t* return_address;
};
struct stack_pos {
stack_ptr saved_data_stack, saved_curr_frame;
};
struct stack_pos stack_get_pos(jq_state* jq) {
struct stack_pos sp = {jq->stk_top, jq->curr_frame};
return sp;
}
void stack_save(jq_state *jq, uint16_t* retaddr, struct stack_pos sp){
jq->fork_top = stack_push_block(&jq->stk, jq->fork_top, sizeof(struct forkpoint));
struct forkpoint* fork = stack_block(&jq->stk, jq->fork_top);
fork->saved_data_stack = jq->stk_top;
fork->saved_curr_frame = jq->curr_frame;
fork->path_len =
jv_get_kind(jq->path) == JV_KIND_ARRAY ? jv_array_length(jv_copy(jq->path)) : 0;
fork->value_at_path = jv_copy(jq->value_at_path);
fork->subexp_nest = jq->subexp_nest;
fork->return_address = retaddr;
jq->stk_top = sp.saved_data_stack;
jq->curr_frame = sp.saved_curr_frame;
}
static int path_intact(jq_state *jq, jv curr) {
if (jq->subexp_nest == 0 && jv_get_kind(jq->path) == JV_KIND_ARRAY) {
return jv_identical(curr, jv_copy(jq->value_at_path));
} else {
jv_free(curr);
return 1;
}
}
static void path_append(jq_state* jq, jv component, jv value_at_path) {
if (jq->subexp_nest == 0 && jv_get_kind(jq->path) == JV_KIND_ARRAY) {
int n1 = jv_array_length(jv_copy(jq->path));
jq->path = jv_array_append(jq->path, component);
int n2 = jv_array_length(jv_copy(jq->path));
assert(n2 == n1 + 1);
jv_free(jq->value_at_path);
jq->value_at_path = value_at_path;
} else {
jv_free(component);
jv_free(value_at_path);
}
}
/* For f_getpath() */
jv
_jq_path_append(jq_state *jq, jv v, jv p, jv value_at_path) {
if (jq->subexp_nest != 0 ||
jv_get_kind(jq->path) != JV_KIND_ARRAY ||
!jv_is_valid(value_at_path)) {
jv_free(v);
jv_free(p);
return value_at_path;
}
if (!jv_identical(v, jv_copy(jq->value_at_path))) {
jv_free(p);
return value_at_path;
}
if (jv_get_kind(p) == JV_KIND_ARRAY)
jq->path = jv_array_concat(jq->path, p);
else
jq->path = jv_array_append(jq->path, p);
jv_free(jq->value_at_path);
return jv_copy(jq->value_at_path = value_at_path);
}
uint16_t* stack_restore(jq_state *jq){
while (!stack_pop_will_free(&jq->stk, jq->fork_top)) {
if (stack_pop_will_free(&jq->stk, jq->stk_top)) {
jv_free(stack_pop(jq));
} else if (stack_pop_will_free(&jq->stk, jq->curr_frame)) {
frame_pop(jq);
} else {
assert(0);
}
}
if (jq->fork_top == 0) {
return 0;
}
struct forkpoint* fork = stack_block(&jq->stk, jq->fork_top);
uint16_t* retaddr = fork->return_address;
jq->stk_top = fork->saved_data_stack;
jq->curr_frame = fork->saved_curr_frame;
int path_len = fork->path_len;
if (jv_get_kind(jq->path) == JV_KIND_ARRAY) {
assert(path_len >= 0);
jq->path = jv_array_slice(jq->path, 0, path_len);
} else {
fork->path_len = 0;
}
jv_free(jq->value_at_path);
jq->value_at_path = fork->value_at_path;
jq->subexp_nest = fork->subexp_nest;
jq->fork_top = stack_pop_block(&jq->stk, jq->fork_top, sizeof(struct forkpoint));
return retaddr;
}
static void jq_reset(jq_state *jq) {
while (stack_restore(jq)) {}
assert(jq->stk_top == 0);
assert(jq->fork_top == 0);
assert(jq->curr_frame == 0);
stack_reset(&jq->stk);
jv_free(jq->error);
jq->error = jv_null();
jq->halted = 0;
jv_free(jq->exit_code);
jv_free(jq->error_message);
if (jv_get_kind(jq->path) != JV_KIND_INVALID)
jv_free(jq->path);
jq->path = jv_null();
jv_free(jq->value_at_path);
jq->value_at_path = jv_null();
jq->subexp_nest = 0;
}
void jq_report_error(jq_state *jq, jv value) {
assert(jq->err_cb);
// callback must jv_free() its jv argument
jq->err_cb(jq->err_cb_data, value);
}
static void set_error(jq_state *jq, jv value) {
// Record so try/catch can find it.
jv_free(jq->error);
jq->error = value;
}
#define ON_BACKTRACK(op) ((op)+NUM_OPCODES)
jv jq_next(jq_state *jq) {
jv cfunc_input[MAX_CFUNCTION_ARGS];
jv_nomem_handler(jq->nomem_handler, jq->nomem_handler_data);
uint16_t* pc = stack_restore(jq);
assert(pc);
int raising;
int backtracking = !jq->initial_execution;
jq->initial_execution = 0;
assert(jv_get_kind(jq->error) == JV_KIND_NULL);
while (1) {
if (jq->halted) {
if (jq->debug_trace_enabled)
printf("\t<halted>\n");
return jv_invalid();
}
uint16_t opcode = *pc;
raising = 0;
if (jq->debug_trace_enabled) {
dump_operation(frame_current(jq)->bc, pc);
printf("\t");
const struct opcode_description* opdesc = opcode_describe(opcode);
stack_ptr param = 0;
if (!backtracking) {
int stack_in = opdesc->stack_in;
if (stack_in == -1) stack_in = pc[1];
param = jq->stk_top;
for (int i=0; i<stack_in; i++) {
if (i != 0) {
printf(" | ");
param = *stack_block_next(&jq->stk, param);
}
if (!param) break;
jv_dump(jv_copy(*(jv*)stack_block(&jq->stk, param)), JV_PRINT_REFCOUNT);
//printf("<%d>", jv_get_refcnt(param->val));
//printf(" -- ");
//jv_dump(jv_copy(jq->path), 0);
}
if (jq->debug_trace_enabled & JQ_DEBUG_TRACE_DETAIL) {
while ((param = *stack_block_next(&jq->stk, param))) {
printf(" || ");
jv_dump(jv_copy(*(jv*)stack_block(&jq->stk, param)), JV_PRINT_REFCOUNT);
}
}
} else {
printf("\t<backtracking>");
}
printf("\n");
}
if (backtracking) {
opcode = ON_BACKTRACK(opcode);
backtracking = 0;
raising = !jv_is_valid(jq->error);
}
pc++;
switch (opcode) {
default: assert(0 && "invalid instruction");
case TOP: break;
case LOADK: {
jv v = jv_array_get(jv_copy(frame_current(jq)->bc->constants), *pc++);
assert(jv_is_valid(v));
jv_free(stack_pop(jq));
stack_push(jq, v);
break;
}
case GENLABEL: {
stack_push(jq, JV_OBJECT(jv_string("__jq"), jv_number(jq->next_label++)));
break;
}
case DUP: {
jv v = stack_pop(jq);
stack_push(jq, jv_copy(v));
stack_push(jq, v);
break;
}
case DUPN: {
jv v = stack_popn(jq);
stack_push(jq, jv_copy(v));
stack_push(jq, v);
break;
}
case DUP2: {
jv keep = stack_pop(jq);
jv v = stack_pop(jq);
stack_push(jq, jv_copy(v));
stack_push(jq, keep);
stack_push(jq, v);
break;
}
case SUBEXP_BEGIN: {
jv v = stack_pop(jq);
stack_push(jq, jv_copy(v));
stack_push(jq, v);
jq->subexp_nest++;
break;
}
case SUBEXP_END: {
assert(jq->subexp_nest > 0);
jq->subexp_nest--;
jv a = stack_pop(jq);
jv b = stack_pop(jq);
stack_push(jq, a);
stack_push(jq, b);
break;
}
case PUSHK_UNDER: {
jv v = jv_array_get(jv_copy(frame_current(jq)->bc->constants), *pc++);
assert(jv_is_valid(v));
jv v2 = stack_pop(jq);
stack_push(jq, v);
stack_push(jq, v2);
break;
}
case POP: {
jv_free(stack_pop(jq));
break;
}
case APPEND: {
jv v = stack_pop(jq);
uint16_t level = *pc++;
uint16_t vidx = *pc++;
jv* var = frame_local_var(jq, vidx, level);
assert(jv_get_kind(*var) == JV_KIND_ARRAY);
*var = jv_array_append(*var, v);
break;
}
case INSERT: {
jv stktop = stack_pop(jq);
jv v = stack_pop(jq);
jv k = stack_pop(jq);
jv objv = stack_pop(jq);
assert(jv_get_kind(objv) == JV_KIND_OBJECT);
if (jv_get_kind(k) == JV_KIND_STRING) {
stack_push(jq, jv_object_set(objv, k, v));
stack_push(jq, stktop);
} else {
char errbuf[15];
set_error(jq, jv_invalid_with_msg(jv_string_fmt("Cannot use %s (%s) as object key",
jv_kind_name(jv_get_kind(k)),
jv_dump_string_trunc(jv_copy(k), errbuf, sizeof(errbuf)))));
jv_free(stktop);
jv_free(v);
jv_free(k);
jv_free(objv);
goto do_backtrack;
}
break;
}
case ON_BACKTRACK(RANGE):
case RANGE: {
uint16_t level = *pc++;
uint16_t v = *pc++;
jv* var = frame_local_var(jq, v, level);
jv max = stack_pop(jq);
if (raising) {
jv_free(max);
goto do_backtrack;
}
if (jv_get_kind(*var) != JV_KIND_NUMBER ||
jv_get_kind(max) != JV_KIND_NUMBER) {
set_error(jq, jv_invalid_with_msg(jv_string_fmt("Range bounds must be numeric")));
jv_free(max);
goto do_backtrack;
} else if (jv_number_value(*var) >= jv_number_value(max)) {
/* finished iterating */
jv_free(max);
goto do_backtrack;
} else {
jv curr = *var;
*var = jv_number(jv_number_value(*var) + 1);
struct stack_pos spos = stack_get_pos(jq);
stack_push(jq, max);
stack_save(jq, pc - 3, spos);
stack_push(jq, curr);
}
break;
}
// FIXME: loadv/storev may do too much copying/freeing
case LOADV: {
uint16_t level = *pc++;
uint16_t v = *pc++;
jv* var = frame_local_var(jq, v, level);
if (jq->debug_trace_enabled) {
printf("V%d = ", v);
jv_dump(jv_copy(*var), 0);
printf(" (%d)\n", jv_get_refcnt(*var));
}
jv_free(stack_pop(jq));
stack_push(jq, jv_copy(*var));
break;
}
// Does a load but replaces the variable with null
case LOADVN: {
uint16_t level = *pc++;
uint16_t v = *pc++;
jv* var = frame_local_var(jq, v, level);
if (jq->debug_trace_enabled) {
printf("V%d = ", v);
jv_dump(jv_copy(*var), 0);
printf(" (%d)\n", jv_get_refcnt(*var));
}
jv_free(stack_popn(jq));
stack_push(jq, *var);
*var = jv_null();
break;
}
case STOREVN:
stack_save(jq, pc - 1, stack_get_pos(jq));
case STOREV: {
uint16_t level = *pc++;
uint16_t v = *pc++;
jv* var = frame_local_var(jq, v, level);
jv val = stack_pop(jq);
if (jq->debug_trace_enabled) {
printf("V%d = ", v);
jv_dump(jv_copy(val), 0);
printf(" (%d)\n", jv_get_refcnt(val));
}
jv_free(*var);
*var = val;
break;
}
case ON_BACKTRACK(STOREVN): {
uint16_t level = *pc++;
uint16_t v = *pc++;
jv* var = frame_local_var(jq, v, level);
jv_free(*var);
*var = jv_null();
goto do_backtrack;
break;
}
case STORE_GLOBAL: {
// Get the constant
jv val = jv_array_get(jv_copy(frame_current(jq)->bc->constants), *pc++);
assert(jv_is_valid(val));
// Store the var
uint16_t level = *pc++;
uint16_t v = *pc++;
jv* var = frame_local_var(jq, v, level);
if (jq->debug_trace_enabled) {
printf("V%d = ", v);
jv_dump(jv_copy(val), 0);
printf(" (%d)\n", jv_get_refcnt(val));
}
jv_free(*var);
*var = val;
break;
}
case PATH_BEGIN: {
jv v = stack_pop(jq);
stack_push(jq, jq->path);
stack_save(jq, pc - 1, stack_get_pos(jq));
stack_push(jq, jv_number(jq->subexp_nest));
stack_push(jq, jq->value_at_path);
stack_push(jq, jv_copy(v));
jq->path = jv_array();
jq->value_at_path = v; // next INDEX operation must index into v
jq->subexp_nest = 0;
break;
}
case PATH_END: {
jv v = stack_pop(jq);
// detect invalid path expression like path(.a | reverse)
if (!path_intact(jq, jv_copy(v))) {
char errbuf[30];
jv msg = jv_string_fmt(
"Invalid path expression with result %s",
jv_dump_string_trunc(v, errbuf, sizeof(errbuf)));
set_error(jq, jv_invalid_with_msg(msg));
goto do_backtrack;
}
jv_free(v); // discard value, only keep path
jv old_value_at_path = stack_pop(jq);
int old_subexp_nest = (int)jv_number_value(stack_pop(jq));
jv path = jq->path;
jq->path = stack_pop(jq);
struct stack_pos spos = stack_get_pos(jq);
stack_push(jq, jv_copy(path));
stack_save(jq, pc - 1, spos);
stack_push(jq, path);
jq->subexp_nest = old_subexp_nest;
jv_free(jq->value_at_path);
jq->value_at_path = old_value_at_path;
break;
}
case ON_BACKTRACK(PATH_BEGIN):
case ON_BACKTRACK(PATH_END): {
jv_free(jq->path);
jq->path = stack_pop(jq);
goto do_backtrack;
}
case INDEX:
case INDEX_OPT: {
jv t = stack_pop(jq);
jv k = stack_pop(jq);
// detect invalid path expression like path(reverse | .a)
if (!path_intact(jq, jv_copy(t))) {
char keybuf[15];
char objbuf[30];
jv msg = jv_string_fmt(
"Invalid path expression near attempt to access element %s of %s",
jv_dump_string_trunc(k, keybuf, sizeof(keybuf)),
jv_dump_string_trunc(t, objbuf, sizeof(objbuf)));
set_error(jq, jv_invalid_with_msg(msg));
goto do_backtrack;
}
jv v = jv_get(t, jv_copy(k));
if (jv_is_valid(v)) {
path_append(jq, k, jv_copy(v));
stack_push(jq, v);
} else {
jv_free(k);
if (opcode == INDEX)
set_error(jq, v);
else
jv_free(v);
goto do_backtrack;
}
break;
}
case JUMP: {
uint16_t offset = *pc++;
pc += offset;
break;
}
case JUMP_F: {
uint16_t offset = *pc++;
jv t = stack_pop(jq);
jv_kind kind = jv_get_kind(t);
if (kind == JV_KIND_FALSE || kind == JV_KIND_NULL) {
pc += offset;
}
stack_push(jq, t); // FIXME do this better
break;
}
case EACH:
case EACH_OPT: {
jv container = stack_pop(jq);
// detect invalid path expression like path(reverse | .[])
if (!path_intact(jq, jv_copy(container))) {
char errbuf[30];
jv msg = jv_string_fmt(
"Invalid path expression near attempt to iterate through %s",
jv_dump_string_trunc(container, errbuf, sizeof(errbuf)));
set_error(jq, jv_invalid_with_msg(msg));
goto do_backtrack;
}
stack_push(jq, container);
stack_push(jq, jv_number(-1));
// fallthrough
}
case ON_BACKTRACK(EACH):
case ON_BACKTRACK(EACH_OPT): {
int idx = jv_number_value(stack_pop(jq));
jv container = stack_pop(jq);
int keep_going, is_last = 0;
jv key, value;
if (jv_get_kind(container) == JV_KIND_ARRAY) {
if (opcode == EACH || opcode == EACH_OPT) idx = 0;
else idx = idx + 1;
int len = jv_array_length(jv_copy(container));
keep_going = idx < len;
is_last = idx == len - 1;
if (keep_going) {
key = jv_number(idx);
value = jv_array_get(jv_copy(container), idx);
}
} else if (jv_get_kind(container) == JV_KIND_OBJECT) {
if (opcode == EACH || opcode == EACH_OPT) idx = jv_object_iter(container);
else idx = jv_object_iter_next(container, idx);
keep_going = jv_object_iter_valid(container, idx);
if (keep_going) {
key = jv_object_iter_key(container, idx);
value = jv_object_iter_value(container, idx);
}
} else {
assert(opcode == EACH || opcode == EACH_OPT);
if (opcode == EACH) {
char errbuf[15];
set_error(jq,
jv_invalid_with_msg(jv_string_fmt("Cannot iterate over %s (%s)",
jv_kind_name(jv_get_kind(container)),
jv_dump_string_trunc(jv_copy(container), errbuf, sizeof(errbuf)))));
}
keep_going = 0;
}
if (!keep_going || raising) {
if (keep_going)
jv_free(value);
jv_free(container);
goto do_backtrack;
} else if (is_last) {
// we don't need to make a backtrack point
jv_free(container);
path_append(jq, key, jv_copy(value));
stack_push(jq, value);
} else {
struct stack_pos spos = stack_get_pos(jq);
stack_push(jq, container);
stack_push(jq, jv_number(idx));
stack_save(jq, pc - 1, spos);
path_append(jq, key, jv_copy(value));
stack_push(jq, value);
}
break;
}
do_backtrack:
case BACKTRACK: {
pc = stack_restore(jq);
if (!pc) {
if (!jv_is_valid(jq->error)) {
jv error = jq->error;
jq->error = jv_null();
return error;
}
return jv_invalid();
}
backtracking = 1;
break;
}
case FORK_OPT:
case DESTRUCTURE_ALT:
case FORK: {
stack_save(jq, pc - 1, stack_get_pos(jq));
pc++; // skip offset this time
break;
}
case ON_BACKTRACK(FORK_OPT):
case ON_BACKTRACK(DESTRUCTURE_ALT): {
if (jv_is_valid(jq->error)) {
// `try EXP ...` backtracked here (no value, `empty`), so we backtrack more
jv_free(stack_pop(jq));
goto do_backtrack;
}
// `try EXP ...` exception caught in EXP
// DESTRUCTURE_ALT doesn't want the error message on the stack,
// as we would just want to throw it away anyway.
if (opcode != ON_BACKTRACK(DESTRUCTURE_ALT)) {
jv_free(stack_pop(jq)); // free the input
stack_push(jq, jv_invalid_get_msg(jq->error)); // push the error's message
} else {
jv_free(jq->error);
}
jq->error = jv_null();
uint16_t offset = *pc++;
pc += offset;
break;
}
case ON_BACKTRACK(FORK): {
if (raising) goto do_backtrack;
uint16_t offset = *pc++;
pc += offset;
break;
}
case CALL_BUILTIN: {
int nargs = *pc++;
jv top = stack_pop(jq);
jv* in = cfunc_input;
in[0] = top;
for (int i = 1; i < nargs; i++) {
in[i] = stack_pop(jq);
}
struct cfunction* function = &frame_current(jq)->bc->globals->cfunctions[*pc++];
typedef jv (*func_1)(jq_state*,jv);
typedef jv (*func_2)(jq_state*,jv,jv);
typedef jv (*func_3)(jq_state*,jv,jv,jv);
typedef jv (*func_4)(jq_state*,jv,jv,jv,jv);
typedef jv (*func_5)(jq_state*,jv,jv,jv,jv,jv);
switch (function->nargs) {
case 1: top = ((func_1)function->fptr)(jq, in[0]); break;
case 2: top = ((func_2)function->fptr)(jq, in[0], in[1]); break;
case 3: top = ((func_3)function->fptr)(jq, in[0], in[1], in[2]); break;
case 4: top = ((func_4)function->fptr)(jq, in[0], in[1], in[2], in[3]); break;
case 5: top = ((func_5)function->fptr)(jq, in[0], in[1], in[2], in[3], in[4]); break;
// FIXME: a) up to 7 arguments (input + 6), b) should assert
// because the compiler should not generate this error.
default: return jv_invalid_with_msg(jv_string("Function takes too many arguments"));
}
if (jv_is_valid(top)) {
stack_push(jq, top);
} else if (jv_invalid_has_msg(jv_copy(top))) {
set_error(jq, top);
goto do_backtrack;
} else {
// C-coded function returns invalid w/o msg? -> backtrack, as if
// it had returned `empty`
goto do_backtrack;
}
break;
}
case TAIL_CALL_JQ:
case CALL_JQ: {
/*
* Bytecode layout here:
*
* CALL_JQ
* <nclosures> (i.e., number of call arguments)
* <callee closure> (what we're calling)
* <nclosures' worth of closures> (frame reference + code pointer)
*
* <next instruction (to return to)>
*
* Each closure consists of two uint16_t values: a "level"
* identifying the frame to be closed over, and an index.
*
* The level is a relative number of call frames reachable from
* the currently one; 0 -> current frame, 1 -> previous frame, and
* so on.
*
* The index is either an index of the closed frame's subfunctions
* or of the closed frame's parameter closures. If the latter,
* that closure will be passed, else the closed frame's pointer
* and the subfunction's code will form the closure to be passed.
*
* See make_closure() for more information.
*/
jv input = stack_pop(jq);
uint16_t nclosures = *pc++;
uint16_t* retaddr = pc + 2 + nclosures*2;
stack_ptr retdata = jq->stk_top;
struct frame* new_frame;
struct closure cl = make_closure(jq, pc);
if (opcode == TAIL_CALL_JQ) {
retaddr = frame_current(jq)->retaddr;
retdata = frame_current(jq)->retdata;
frame_pop(jq);
}
new_frame = frame_push(jq, cl, pc + 2, nclosures);
new_frame->retdata = retdata;
new_frame->retaddr = retaddr;
pc = new_frame->bc->code;
stack_push(jq, input);
break;
}
case RET: {
jv value = stack_pop(jq);
assert(jq->stk_top == frame_current(jq)->retdata);
uint16_t* retaddr = frame_current(jq)->retaddr;
if (retaddr) {
// function return
pc = retaddr;
frame_pop(jq);
} else {
// top-level return, yielding value
struct stack_pos spos = stack_get_pos(jq);
stack_push(jq, jv_null());
stack_save(jq, pc - 1, spos);
return value;
}
stack_push(jq, value);
break;
}
case ON_BACKTRACK(RET): {
// resumed after top-level return
goto do_backtrack;
}
}
}
}
jv jq_format_error(jv msg) {
if (jv_get_kind(msg) == JV_KIND_NULL ||
(jv_get_kind(msg) == JV_KIND_INVALID && !jv_invalid_has_msg(jv_copy(msg)))) {
jv_free(msg);
fprintf(stderr, "jq: error: out of memory\n");
return jv_null();
}
if (jv_get_kind(msg) == JV_KIND_STRING)
return msg; // expected to already be formatted
if (jv_get_kind(msg) == JV_KIND_INVALID)
msg = jv_invalid_get_msg(msg);
if (jv_get_kind(msg) == JV_KIND_NULL)
return jq_format_error(msg); // ENOMEM
// Invalid with msg; prefix with "jq: error: "
if (jv_get_kind(msg) != JV_KIND_INVALID) {
if (jv_get_kind(msg) == JV_KIND_STRING)
return jv_string_fmt("jq: error: %s", jv_string_value(msg));
msg = jv_dump_string(msg, JV_PRINT_INVALID);
if (jv_get_kind(msg) == JV_KIND_STRING)
return jv_string_fmt("jq: error: %s", jv_string_value(msg));
return jq_format_error(jv_null()); // ENOMEM
}
// An invalid inside an invalid!
return jq_format_error(jv_invalid_get_msg(msg));
}
// XXX Refactor into a utility function that returns a jv and one that
// uses it and then prints that jv's string as the complete error
// message.
static void default_err_cb(void *data, jv msg) {
msg = jq_format_error(msg);
fprintf((FILE *)data, "%s\n", jv_string_value(msg));
jv_free(msg);
}
jq_state *jq_init(void) {
jq_state *jq;
jq = jv_mem_alloc_unguarded(sizeof(*jq));
if (jq == NULL)
return NULL;
jq->bc = 0;
jq->next_label = 0;
stack_init(&jq->stk);
jq->stk_top = 0;
jq->fork_top = 0;
jq->curr_frame = 0;
jq->error = jv_null();
jq->halted = 0;
jq->exit_code = jv_invalid();
jq->error_message = jv_invalid();
jq->err_cb = default_err_cb;
jq->err_cb_data = stderr;
jq->attrs = jv_object();
jq->path = jv_null();
jq->value_at_path = jv_null();
jq->nomem_handler = NULL;
jq->nomem_handler_data = NULL;
return jq;
}
void jq_set_error_cb(jq_state *jq, jq_msg_cb cb, void *data) {
if (cb == NULL) {
jq->err_cb = default_err_cb;
jq->err_cb_data = stderr;
} else {
jq->err_cb = cb;
jq->err_cb_data = data;
}
}
void jq_get_error_cb(jq_state *jq, jq_msg_cb *cb, void **data) {
*cb = jq->err_cb;
*data = jq->err_cb_data;
}
void jq_set_nomem_handler(jq_state *jq, void (*nomem_handler)(void *), void *data) {
jv_nomem_handler(nomem_handler, data);
jq->nomem_handler = nomem_handler;
jq->nomem_handler_data = data;
}
void jq_start(jq_state *jq, jv input, int flags) {
jv_nomem_handler(jq->nomem_handler, jq->nomem_handler_data);
jq_reset(jq);
struct closure top = {jq->bc, -1};
struct frame* top_frame = frame_push(jq, top, 0, 0);
top_frame->retdata = 0;
top_frame->retaddr = 0;
stack_push(jq, input);
stack_save(jq, jq->bc->code, stack_get_pos(jq));
jq->debug_trace_enabled = flags & JQ_DEBUG_TRACE_ALL;
jq->initial_execution = 1;
}
void jq_teardown(jq_state **jq) {
jq_state *old_jq = *jq;
if (old_jq == NULL)
return;
*jq = NULL;
jq_reset(old_jq);
bytecode_free(old_jq->bc);
old_jq->bc = 0;
jv_free(old_jq->attrs);
jv_mem_free(old_jq);
}
static int ret_follows(uint16_t *pc) {
if (*pc == RET)
return 1;
if (*pc++ != JUMP)
return 0;
return ret_follows(pc + *pc + 1); // FIXME, might be ironic
}
/*
* Look for tail calls that can be optimized: tail calls with no
* references left to the current frame.
*
* We're staring at this bytecode layout:
*
* CALL_JQ
* <nclosures>
* <callee closure> (2 units)
* <nclosures closures> (2 units each)
* <next instruction>
*
* A closure is:
*
* <level> (a relative frame count chased via the current frame's env)
* <index> (an index of a subfunction or closure in that frame)
*
* We're looking for:
*
* a) the next instruction is a RET or a chain of unconditional JUMPs
* that ends in a RET, and
*
* b) none of the closures -callee included- have level == 0.
*/
static uint16_t tail_call_analyze(uint16_t *pc) {
assert(*pc == CALL_JQ);
pc++;
// + 1 for the callee closure
for (uint16_t nclosures = *pc++ + 1; nclosures > 0; pc++, nclosures--) {
if (*pc++ == 0)
return CALL_JQ;
}
if (ret_follows(pc))
return TAIL_CALL_JQ;
return CALL_JQ;
}
static struct bytecode *optimize_code(struct bytecode *bc) {
uint16_t *pc = bc->code;
// FIXME: Don't mutate bc->code...
while (pc < bc->code + bc->codelen) {
switch (*pc) {
case CALL_JQ:
*pc = tail_call_analyze(pc);
break;
// Other bytecode optimizations here. A peephole optimizer would
// fit right in.
default: break;
}
pc += bytecode_operation_length(pc);
}
return bc;
}
static struct bytecode *optimize(struct bytecode *bc) {
for (int i=0; i<bc->nsubfunctions; i++) {
bc->subfunctions[i] = optimize(bc->subfunctions[i]);
}
return optimize_code(bc);
}
static jv
args2obj(jv args)
{
if (jv_get_kind(args) == JV_KIND_OBJECT)
return args;
assert(jv_get_kind(args) == JV_KIND_ARRAY);
jv r = jv_object();
jv kk = jv_string("name");
jv vk = jv_string("value");
jv_array_foreach(args, i, v)
r = jv_object_set(r, jv_object_get(jv_copy(v), kk), jv_object_get(v, vk));
jv_free(args);
jv_free(kk);
jv_free(vk);
return r;
}
int jq_compile_args(jq_state *jq, const char* str, jv args) {
jv_nomem_handler(jq->nomem_handler, jq->nomem_handler_data);
assert(jv_get_kind(args) == JV_KIND_ARRAY || jv_get_kind(args) == JV_KIND_OBJECT);
struct locfile* locations;
locations = locfile_init(jq, "<top-level>", str, strlen(str));
block program;
jq_reset(jq);
if (jq->bc) {
bytecode_free(jq->bc);
jq->bc = 0;
}
int nerrors = load_program(jq, locations, &program);
if (nerrors == 0) {
nerrors = builtins_bind(jq, &program);
if (nerrors == 0) {
nerrors = block_compile(program, &jq->bc, locations, args = args2obj(args));
}
} else
jv_free(args);
if (nerrors)
jq_report_error(jq, jv_string_fmt("jq: %d compile %s", nerrors, nerrors > 1 ? "errors" : "error"));
if (jq->bc)
jq->bc = optimize(jq->bc);
locfile_free(locations);
return jq->bc != NULL;
}
int jq_compile(jq_state *jq, const char* str) {
return jq_compile_args(jq, str, jv_object());
}
jv jq_get_jq_origin(jq_state *jq) {
return jq_get_attr(jq, jv_string("JQ_ORIGIN"));
}
jv jq_get_prog_origin(jq_state *jq) {
return jq_get_attr(jq, jv_string("PROGRAM_ORIGIN"));
}
jv jq_get_lib_dirs(jq_state *jq) {
return jq_get_attr(jq, jv_string("JQ_LIBRARY_PATH"));
}
void jq_set_attrs(jq_state *jq, jv attrs) {
assert(jv_get_kind(attrs) == JV_KIND_OBJECT);
jv_free(jq->attrs);
jq->attrs = attrs;
}
void jq_set_attr(jq_state *jq, jv attr, jv val) {
jq->attrs = jv_object_set(jq->attrs, attr, val);
}
jv jq_get_attr(jq_state *jq, jv attr) {
return jv_object_get(jv_copy(jq->attrs), attr);
}
void jq_dump_disassembly(jq_state *jq, int indent) {
dump_disassembly(indent, jq->bc);
}
void jq_set_input_cb(jq_state *jq, jq_input_cb cb, void *data) {
jq->input_cb = cb;
jq->input_cb_data = data;
}
void jq_get_input_cb(jq_state *jq, jq_input_cb *cb, void **data) {
*cb = jq->input_cb;
*data = jq->input_cb_data;
}
void jq_set_debug_cb(jq_state *jq, jq_msg_cb cb, void *data) {
jq->debug_cb = cb;
jq->debug_cb_data = data;
}
void jq_get_debug_cb(jq_state *jq, jq_msg_cb *cb, void **data) {
*cb = jq->debug_cb;
*data = jq->debug_cb_data;
}
void
jq_halt(jq_state *jq, jv exit_code, jv error_message)
{
assert(!jq->halted);
jq->halted = 1;
jq->exit_code = exit_code;
jq->error_message = error_message;
}
int
jq_halted(jq_state *jq)
{
return jq->halted;
}
jv jq_get_exit_code(jq_state *jq)
{
return jv_copy(jq->exit_code);
}
jv jq_get_error_message(jq_state *jq)
{
return jv_copy(jq->error_message);
}
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