llparse
Version:
Compile incremental parsers to C code
315 lines • 11.4 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.TableLookup = void 0;
const assert = require("assert");
const base_1 = require("./base");
const MAX_CHAR = 0xff;
const TABLE_GROUP = 16;
// _mm_cmpestri takes 8 ranges
const SSE_RANGES_LEN = 16;
// _mm_cmpestri takes 128bit input
const SSE_RANGES_PAD = 16;
const MAX_SSE_CALLS = 2;
const MAX_NEON_RANGES = 6;
const MAX_WASM_RANGES = 6;
const SSE_ALIGNMENT = 16;
class TableLookup extends base_1.Node {
doBuild(out) {
const ctx = this.compilation;
const table = this.buildTable();
for (const line of table.declaration) {
out.push(line);
}
this.prologue(out);
const transform = ctx.unwrapTransform(this.ref.transform);
// Try to vectorize nodes matching characters and looping to themselves
// NOTE: `switch` below triggers when there is not enough characters in the
// stream for vectorized processing.
if (this.canVectorize()) {
this.buildSSE(out);
this.buildNeon(out);
this.buildWASM(out);
}
const current = transform.build(ctx, `*${ctx.posArg()}`);
out.push(`switch (${table.name}[(uint8_t) ${current}]) {`);
for (const [index, edge] of this.ref.edges.entries()) {
out.push(` case ${index + 1}: {`);
const tmp = [];
this.tailTo(tmp, {
noAdvance: edge.noAdvance,
node: edge.node,
value: undefined,
});
ctx.indent(out, tmp, ' ');
out.push(' }');
}
out.push(` default: {`);
const tmp = [];
this.tailTo(tmp, this.ref.otherwise);
ctx.indent(out, tmp, ' ');
out.push(' }');
out.push('}');
}
canVectorize() {
// Transformation is not supported atm
if (this.ref.transform && this.ref.transform.ref.name !== 'id') {
return false;
}
if (this.ref.edges.length !== 1) {
return false;
}
const edge = this.ref.edges[0];
if (!edge ||
edge.node.ref !== this.ref) {
return false;
}
assert.strictEqual(edge.noAdvance, false);
return true;
}
buildRanges(edge) {
// NOTE: keys are sorted
const ranges = [];
let first;
let last;
for (const key of edge.keys) {
if (first === undefined) {
first = key;
}
if (last === undefined) {
last = key;
}
if (key - last > 1) {
ranges.push(first, last);
first = key;
}
last = key;
}
if (first !== undefined && last !== undefined) {
ranges.push(first, last);
}
return ranges;
}
buildSSE(out) {
const ctx = this.compilation;
const edge = this.ref.edges[0];
assert(edge !== undefined);
const ranges = this.buildRanges(edge);
if (ranges.length === 0) {
return false;
}
// Way too many calls would be required
if (ranges.length > MAX_SSE_CALLS * SSE_RANGES_LEN) {
return false;
}
out.push('#ifdef __SSE4_2__');
out.push(`if (${ctx.endPosArg()} - ${ctx.posArg()} >= 16) {`);
out.push(' __m128i ranges;');
out.push(' __m128i input;');
out.push(' int match_len;');
out.push('');
out.push(' /* Load input */');
out.push(` input = _mm_loadu_si128((__m128i const*) ${ctx.posArg()});`);
for (let off = 0; off < ranges.length; off += SSE_RANGES_LEN) {
const subRanges = ranges.slice(off, off + SSE_RANGES_LEN);
let paddedRanges = subRanges.slice();
while (paddedRanges.length < SSE_RANGES_PAD) {
paddedRanges.push(0);
}
const blob = ctx.blob(Buffer.from(paddedRanges), SSE_ALIGNMENT);
out.push(` ranges = _mm_loadu_si128((__m128i const*) ${blob});`);
out.push('');
out.push(' /* Find first character that does not match `ranges` */');
out.push(` match_len = _mm_cmpestri(ranges, ${subRanges.length},`);
out.push(' input, 16,');
out.push(' _SIDD_UBYTE_OPS | _SIDD_CMP_RANGES |');
out.push(' _SIDD_NEGATIVE_POLARITY);');
out.push('');
out.push(' if (match_len != 0) {');
out.push(` ${ctx.posArg()} += match_len;`);
const tmp = [];
this.tailTo(tmp, {
noAdvance: true,
node: edge.node,
});
ctx.indent(out, tmp, ' ');
out.push(' }');
}
{
const tmp = [];
this.tailTo(tmp, this.ref.otherwise);
ctx.indent(out, tmp, ' ');
}
out.push('}');
out.push('#endif /* __SSE4_2__ */');
return true;
}
buildNeon(out) {
const ctx = this.compilation;
const edge = this.ref.edges[0];
assert(edge !== undefined);
const ranges = this.buildRanges(edge);
if (ranges.length === 0) {
return false;
}
// Way too many calls would be required
if (ranges.length > MAX_NEON_RANGES) {
return false;
}
out.push('#ifdef __ARM_NEON__');
out.push(`while (${ctx.endPosArg()} - ${ctx.posArg()} >= 16) {`);
out.push(' uint8x16_t input;');
out.push(' uint8x16_t single;');
out.push(' uint8x16_t mask;');
out.push(' uint8x8_t narrow;');
out.push(' uint64_t match_mask;');
out.push(' int match_len;');
out.push('');
out.push(' /* Load input */');
out.push(` input = vld1q_u8(${ctx.posArg()});`);
out.push(' /* Find first character that does not match `ranges` */');
function v128(value) {
return `vdupq_n_u8(${ctx.toChar(value)})`;
}
for (let off = 0; off < ranges.length; off += 2) {
const start = ranges[off];
const end = ranges[off + 1];
assert(start !== undefined);
assert(end !== undefined);
// Same character, equality is sufficient (and faster)
if (start === end) {
out.push(` single = vceqq_u8(input, ${v128(start)});`);
}
else {
out.push(` single = vandq_u16(`);
out.push(` vcgeq_u8(input, ${v128(start)}),`);
out.push(` vcleq_u8(input, ${v128(end)})`);
out.push(' );');
}
if (off === 0) {
out.push(' mask = single;');
}
else {
out.push(' mask = vorrq_u16(mask, single);');
}
}
// https://community.arm.com/arm-community-blogs/b/servers-and-cloud-computing-blog/posts/porting-x86-vector-bitmask-optimizations-to-arm-neon
out.push(' narrow = vshrn_n_u16(mask, 4);');
out.push(' match_mask = ~vget_lane_u64(vreinterpret_u64_u8(narrow), 0);');
out.push(' match_len = __builtin_ctzll(match_mask) >> 2;');
out.push(' if (match_len != 16) {');
out.push(` ${ctx.posArg()} += match_len;`);
{
const tmp = [];
this.tailTo(tmp, this.ref.otherwise);
ctx.indent(out, tmp, ' ');
}
out.push(' }');
out.push(` ${ctx.posArg()} += 16;`);
out.push('}');
out.push(`if (${ctx.posArg()} == ${ctx.endPosArg()}) {`);
{
const tmp = [];
this.pause(tmp);
this.compilation.indent(out, tmp, ' ');
}
out.push('}');
out.push('#endif /* __ARM_NEON__ */');
return true;
}
buildWASM(out) {
const ctx = this.compilation;
const edge = this.ref.edges[0];
assert(edge !== undefined);
const ranges = this.buildRanges(edge);
if (ranges.length === 0) {
return false;
}
// Way too many calls would be required
if (ranges.length > MAX_WASM_RANGES) {
return false;
}
out.push('#ifdef __wasm_simd128__');
out.push(`while (${ctx.endPosArg()} - ${ctx.posArg()} >= 16) {`);
out.push(' v128_t input;');
out.push(' v128_t mask;');
out.push(' v128_t single;');
out.push(' int match_len;');
out.push('');
out.push(' /* Load input */');
out.push(` input = wasm_v128_load(${ctx.posArg()});`);
out.push(' /* Find first character that does not match `ranges` */');
function v128(value) {
return `wasm_u8x16_const_splat(${ctx.toChar(value)})`;
}
for (let off = 0; off < ranges.length; off += 2) {
const start = ranges[off];
const end = ranges[off + 1];
assert(start !== undefined);
assert(end !== undefined);
// Same character, equality is sufficient (and faster)
if (start === end) {
out.push(` single = wasm_i8x16_eq(input, ${v128(start)});`);
}
else {
out.push(` single = wasm_v128_and(`);
out.push(` wasm_i8x16_ge(input, ${v128(start)}),`);
out.push(` wasm_i8x16_le(input, ${v128(end)})`);
out.push(' );');
}
if (off === 0) {
out.push(' mask = single;');
}
else {
out.push(' mask = wasm_v128_or(mask, single);');
}
}
out.push(' match_len = __builtin_ctz(');
out.push(' ~wasm_i8x16_bitmask(mask)');
out.push(' );');
out.push(' if (match_len != 16) {');
out.push(` ${ctx.posArg()} += match_len;`);
{
const tmp = [];
this.tailTo(tmp, this.ref.otherwise);
ctx.indent(out, tmp, ' ');
}
out.push(' }');
out.push(` ${ctx.posArg()} += 16;`);
out.push('}');
out.push(`if (${ctx.posArg()} == ${ctx.endPosArg()}) {`);
{
const tmp = [];
this.pause(tmp);
this.compilation.indent(out, tmp, ' ');
}
out.push('}');
out.push('#endif /* __wasm_simd128__ */');
return true;
}
buildTable() {
const table = new Array(MAX_CHAR + 1).fill(0);
for (const [index, edge] of this.ref.edges.entries()) {
edge.keys.forEach((key) => {
assert.strictEqual(table[key], 0);
table[key] = index + 1;
});
}
const lines = [
'static uint8_t lookup_table[] = {',
];
for (let i = 0; i < table.length; i += TABLE_GROUP) {
let line = ` ${table.slice(i, i + TABLE_GROUP).join(', ')}`;
if (i + TABLE_GROUP < table.length) {
line += ',';
}
lines.push(line);
}
lines.push('};');
return {
name: 'lookup_table',
declaration: lines,
};
}
}
exports.TableLookup = TableLookup;
//# sourceMappingURL=table-lookup.js.map