| 1 | /** |
| 2 | * Copyright (c) Meta Platforms, Inc. and affiliates. |
| 3 | * |
| 4 | * This source code is licensed under the MIT license found in the |
| 5 | * LICENSE file in the root directory of this source tree. |
| 6 | */ |
| 7 | |
| 8 | import {isValidIdentifier} from '@babel/types'; |
| 9 | import {CompilerError} from '../CompilerError'; |
| 10 | import { |
| 11 | GeneratedSource, |
| 12 | GotoVariant, |
| 13 | HIRFunction, |
| 14 | IdentifierId, |
| 15 | Instruction, |
| 16 | InstructionValue, |
| 17 | LoadGlobal, |
| 18 | Phi, |
| 19 | Place, |
| 20 | Primitive, |
| 21 | assertConsistentIdentifiers, |
| 22 | assertTerminalSuccessorsExist, |
| 23 | makePropertyLiteral, |
| 24 | markInstructionIds, |
| 25 | markPredecessors, |
| 26 | mergeConsecutiveBlocks, |
| 27 | reversePostorderBlocks, |
| 28 | } from '../HIR'; |
| 29 | import { |
| 30 | removeDeadDoWhileStatements, |
| 31 | removeUnnecessaryTryCatch, |
| 32 | removeUnreachableForUpdates, |
| 33 | } from '../HIR/HIRBuilder'; |
| 34 | import {eliminateRedundantPhi} from '../SSA'; |
| 35 | |
| 36 | /* |
| 37 | * Applies constant propagation/folding to the given function. The approach is |
| 38 | * [Sparse Conditional Constant Propagation](https://en.wikipedia.org/wiki/Sparse_conditional_constant_propagation): |
| 39 | * we use abstract interpretation to record known constant values for identifiers, |
| 40 | * with lack of a value indicating that the identifier does not have a |
| 41 | * known constant value. |
| 42 | * |
| 43 | * Instructions which can be compile-time evaluated *and* whose operands are known constants |
| 44 | * are replaced with the resulting constant value. For example a BinaryExpression |
| 45 | * where the left value is known to be `1` and the right value is known to be `2` |
| 46 | * can be replaced with a `Constant 3` instruction. |
| 47 | * |
| 48 | * This pass also exploits the use of SSA form, tracking the constant values of |
| 49 | * local variables. For example, in `let x = 4; let y = x + 1` we know that |
| 50 | * `x = 4` in the binary expression and can replace the binary expression with |
| 51 | * `Constant 5`. |
| 52 | * |
| 53 | * This pass also visits conditionals (currently only IfTerminal) and can prune |
| 54 | * unreachable branches when the condition is a known truthy/falsey constant. The |
| 55 | * pass uses fixpoint iteration, looping until no additional updates can be |
| 56 | * performed. This allows the compiler to find cases where once one conditional is pruned, |
| 57 | * other values become constant, allowing subsequent conditionals to be pruned and so on. |
| 58 | */ |
| 59 | export function constantPropagation(fn: HIRFunction): void { |
| 60 | const constants: Constants = new Map(); |
| 61 | constantPropagationImpl(fn, constants); |
| 62 | } |
| 63 | |
| 64 | function constantPropagationImpl(fn: HIRFunction, constants: Constants): void { |
| 65 | while (true) { |
| 66 | const haveTerminalsChanged = applyConstantPropagation(fn, constants); |
| 67 | if (!haveTerminalsChanged) { |
| 68 | break; |
| 69 | } |
| 70 | /* |
| 71 | * If terminals have changed then blocks may have become newly unreachable. |
| 72 | * Re-run minification of the graph (incl reordering instruction ids) |
| 73 | */ |
| 74 | reversePostorderBlocks(fn.body); |
| 75 | removeUnreachableForUpdates(fn.body); |
| 76 | removeDeadDoWhileStatements(fn.body); |
| 77 | removeUnnecessaryTryCatch(fn.body); |
| 78 | markInstructionIds(fn.body); |
| 79 | markPredecessors(fn.body); |
| 80 | |
| 81 | // Now that predecessors are updated, prune phi operands that can never be reached |
| 82 | for (const [, block] of fn.body.blocks) { |
| 83 | for (const phi of block.phis) { |
| 84 | for (const [predecessor] of phi.operands) { |
| 85 | if (!block.preds.has(predecessor)) { |
| 86 | phi.operands.delete(predecessor); |
| 87 | } |
| 88 | } |
| 89 | } |
| 90 | } |
| 91 | /* |
| 92 | * By removing some phi operands, there may be phis that were not previously |
| 93 | * redundant but now are |
| 94 | */ |
| 95 | eliminateRedundantPhi(fn); |
| 96 | /* |
| 97 | * Finally, merge together any blocks that are now guaranteed to execute |
| 98 | * consecutively |
| 99 | */ |
| 100 | mergeConsecutiveBlocks(fn); |
| 101 | |
| 102 | assertConsistentIdentifiers(fn); |
| 103 | assertTerminalSuccessorsExist(fn); |
| 104 | } |
| 105 | } |
| 106 | |
| 107 | function applyConstantPropagation( |
| 108 | fn: HIRFunction, |
| 109 | constants: Constants, |
| 110 | ): boolean { |
| 111 | let hasChanges = false; |
| 112 | for (const [, block] of fn.body.blocks) { |
| 113 | /* |
| 114 | * Initialize phi values if all operands have the same known constant value. |
| 115 | * Note that this analysis uses a single-pass only, so it will never fill in |
| 116 | * phi values for blocks that have a back-edge. |
| 117 | */ |
| 118 | for (const phi of block.phis) { |
| 119 | let value = evaluatePhi(phi, constants); |
| 120 | if (value !== null) { |
| 121 | constants.set(phi.place.identifier.id, value); |
| 122 | } |
| 123 | } |
| 124 | |
| 125 | for (let i = 0; i < block.instructions.length; i++) { |
| 126 | if (block.kind === 'sequence' && i === block.instructions.length - 1) { |
| 127 | /* |
| 128 | * evaluating the last value of a value block can break order of evaluation, |
| 129 | * skip these instructions |
| 130 | */ |
| 131 | continue; |
| 132 | } |
| 133 | const instr = block.instructions[i]!; |
| 134 | const value = evaluateInstruction(constants, instr); |
| 135 | if (value !== null) { |
| 136 | constants.set(instr.lvalue.identifier.id, value); |
| 137 | } |
| 138 | } |
| 139 | |
| 140 | const terminal = block.terminal; |
| 141 | switch (terminal.kind) { |
| 142 | case 'if': { |
| 143 | const testValue = read(constants, terminal.test); |
| 144 | if (testValue !== null && testValue.kind === 'Primitive') { |
| 145 | hasChanges = true; |
| 146 | const targetBlockId = testValue.value |
| 147 | ? terminal.consequent |
| 148 | : terminal.alternate; |
| 149 | block.terminal = { |
| 150 | kind: 'goto', |
| 151 | variant: GotoVariant.Break, |
| 152 | block: targetBlockId, |
| 153 | id: terminal.id, |
| 154 | loc: terminal.loc, |
| 155 | }; |
| 156 | } |
| 157 | break; |
| 158 | } |
| 159 | default: { |
| 160 | // no-op |
| 161 | } |
| 162 | } |
| 163 | } |
| 164 | |
| 165 | return hasChanges; |
| 166 | } |
| 167 | |
| 168 | function evaluatePhi(phi: Phi, constants: Constants): Constant | null { |
| 169 | let value: Constant | null = null; |
| 170 | for (const [, operand] of phi.operands) { |
| 171 | const operandValue = constants.get(operand.identifier.id) ?? null; |
| 172 | // did not find a constant, can't constant propogate |
| 173 | if (operandValue === null) { |
| 174 | return null; |
| 175 | } |
| 176 | |
| 177 | /* |
| 178 | * first iteration of the loop, let's store the operand and continue |
| 179 | * looping. |
| 180 | */ |
| 181 | if (value === null) { |
| 182 | value = operandValue; |
| 183 | continue; |
| 184 | } |
| 185 | |
| 186 | // found different kinds of constants, can't constant propogate |
| 187 | if (operandValue.kind !== value.kind) { |
| 188 | return null; |
| 189 | } |
| 190 | |
| 191 | switch (operandValue.kind) { |
| 192 | case 'Primitive': { |
| 193 | CompilerError.invariant(value.kind === 'Primitive', { |
| 194 | reason: 'value kind expected to be Primitive', |
| 195 | loc: GeneratedSource, |
| 196 | }); |
| 197 | |
| 198 | // different constant values, can't constant propogate |
| 199 | if (operandValue.value !== value.value) { |
| 200 | return null; |
| 201 | } |
| 202 | break; |
| 203 | } |
| 204 | case 'LoadGlobal': { |
| 205 | CompilerError.invariant(value.kind === 'LoadGlobal', { |
| 206 | reason: 'value kind expected to be LoadGlobal', |
| 207 | loc: GeneratedSource, |
| 208 | }); |
| 209 | |
| 210 | // different global values, can't constant propogate |
| 211 | if (operandValue.binding.name !== value.binding.name) { |
| 212 | return null; |
| 213 | } |
| 214 | break; |
| 215 | } |
| 216 | default: |
| 217 | return null; |
| 218 | } |
| 219 | } |
| 220 | |
| 221 | return value; |
| 222 | } |
| 223 | |
| 224 | function evaluateInstruction( |
| 225 | constants: Constants, |
| 226 | instr: Instruction, |
| 227 | ): Constant | null { |
| 228 | const value = instr.value; |
| 229 | switch (value.kind) { |
| 230 | case 'Primitive': { |
| 231 | return value; |
| 232 | } |
| 233 | case 'LoadGlobal': { |
| 234 | return value; |
| 235 | } |
| 236 | case 'ComputedLoad': { |
| 237 | const property = read(constants, value.property); |
| 238 | if ( |
| 239 | property !== null && |
| 240 | property.kind === 'Primitive' && |
| 241 | ((typeof property.value === 'string' && |
| 242 | isValidIdentifier(property.value)) || |
| 243 | typeof property.value === 'number') |
| 244 | ) { |
| 245 | const nextValue: InstructionValue = { |
| 246 | kind: 'PropertyLoad', |
| 247 | loc: value.loc, |
| 248 | property: makePropertyLiteral(property.value), |
| 249 | object: value.object, |
| 250 | }; |
| 251 | instr.value = nextValue; |
| 252 | } |
| 253 | return null; |
| 254 | } |
| 255 | case 'ComputedStore': { |
| 256 | const property = read(constants, value.property); |
| 257 | if ( |
| 258 | property !== null && |
| 259 | property.kind === 'Primitive' && |
| 260 | ((typeof property.value === 'string' && |
| 261 | isValidIdentifier(property.value)) || |
| 262 | typeof property.value === 'number') |
| 263 | ) { |
| 264 | const nextValue: InstructionValue = { |
| 265 | kind: 'PropertyStore', |
| 266 | loc: value.loc, |
| 267 | property: makePropertyLiteral(property.value), |
| 268 | object: value.object, |
| 269 | value: value.value, |
| 270 | }; |
| 271 | instr.value = nextValue; |
| 272 | } |
| 273 | return null; |
| 274 | } |
| 275 | case 'PostfixUpdate': { |
| 276 | const previous = read(constants, value.value); |
| 277 | if ( |
| 278 | previous !== null && |
| 279 | previous.kind === 'Primitive' && |
| 280 | typeof previous.value === 'number' |
| 281 | ) { |
| 282 | const next = |
| 283 | value.operation === '++' ? previous.value + 1 : previous.value - 1; |
| 284 | // Store the updated value |
| 285 | constants.set(value.lvalue.identifier.id, { |
| 286 | kind: 'Primitive', |
| 287 | value: next, |
| 288 | loc: value.loc, |
| 289 | }); |
| 290 | // But return the value prior to the update |
| 291 | return previous; |
| 292 | } |
| 293 | return null; |
| 294 | } |
| 295 | case 'PrefixUpdate': { |
| 296 | const previous = read(constants, value.value); |
| 297 | if ( |
| 298 | previous !== null && |
| 299 | previous.kind === 'Primitive' && |
| 300 | typeof previous.value === 'number' |
| 301 | ) { |
| 302 | const next: Primitive = { |
| 303 | kind: 'Primitive', |
| 304 | value: |
| 305 | value.operation === '++' ? previous.value + 1 : previous.value - 1, |
| 306 | loc: value.loc, |
| 307 | }; |
| 308 | // Store and return the updated value |
| 309 | constants.set(value.lvalue.identifier.id, next); |
| 310 | return next; |
| 311 | } |
| 312 | return null; |
| 313 | } |
| 314 | case 'UnaryExpression': { |
| 315 | switch (value.operator) { |
| 316 | case '!': { |
| 317 | const operand = read(constants, value.value); |
| 318 | if (operand !== null && operand.kind === 'Primitive') { |
| 319 | const result: Primitive = { |
| 320 | kind: 'Primitive', |
| 321 | value: !operand.value, |
| 322 | loc: value.loc, |
| 323 | }; |
| 324 | instr.value = result; |
| 325 | return result; |
| 326 | } |
| 327 | return null; |
| 328 | } |
| 329 | case '-': { |
| 330 | const operand = read(constants, value.value); |
| 331 | if ( |
| 332 | operand !== null && |
| 333 | operand.kind === 'Primitive' && |
| 334 | typeof operand.value === 'number' |
| 335 | ) { |
| 336 | const result: Primitive = { |
| 337 | kind: 'Primitive', |
| 338 | value: operand.value * -1, |
| 339 | loc: value.loc, |
| 340 | }; |
| 341 | instr.value = result; |
| 342 | return result; |
| 343 | } |
| 344 | return null; |
| 345 | } |
| 346 | default: |
| 347 | return null; |
| 348 | } |
| 349 | } |
| 350 | case 'BinaryExpression': { |
| 351 | const lhsValue = read(constants, value.left); |
| 352 | const rhsValue = read(constants, value.right); |
| 353 | if ( |
| 354 | lhsValue !== null && |
| 355 | rhsValue !== null && |
| 356 | lhsValue.kind === 'Primitive' && |
| 357 | rhsValue.kind === 'Primitive' |
| 358 | ) { |
| 359 | const lhs = lhsValue.value; |
| 360 | const rhs = rhsValue.value; |
| 361 | let result: Primitive | null = null; |
| 362 | switch (value.operator) { |
| 363 | case '+': { |
| 364 | if (typeof lhs === 'number' && typeof rhs === 'number') { |
| 365 | result = {kind: 'Primitive', value: lhs + rhs, loc: value.loc}; |
| 366 | } else if (typeof lhs === 'string' && typeof rhs === 'string') { |
| 367 | result = {kind: 'Primitive', value: lhs + rhs, loc: value.loc}; |
| 368 | } |
| 369 | break; |
| 370 | } |
| 371 | case '-': { |
| 372 | if (typeof lhs === 'number' && typeof rhs === 'number') { |
| 373 | result = {kind: 'Primitive', value: lhs - rhs, loc: value.loc}; |
| 374 | } |
| 375 | break; |
| 376 | } |
| 377 | case '*': { |
| 378 | if (typeof lhs === 'number' && typeof rhs === 'number') { |
| 379 | result = {kind: 'Primitive', value: lhs * rhs, loc: value.loc}; |
| 380 | } |
| 381 | break; |
| 382 | } |
| 383 | case '/': { |
| 384 | if (typeof lhs === 'number' && typeof rhs === 'number') { |
| 385 | result = {kind: 'Primitive', value: lhs / rhs, loc: value.loc}; |
| 386 | } |
| 387 | break; |
| 388 | } |
| 389 | case '|': { |
| 390 | if (typeof lhs === 'number' && typeof rhs === 'number') { |
| 391 | result = {kind: 'Primitive', value: lhs | rhs, loc: value.loc}; |
| 392 | } |
| 393 | break; |
| 394 | } |
| 395 | case '&': { |
| 396 | if (typeof lhs === 'number' && typeof rhs === 'number') { |
| 397 | result = {kind: 'Primitive', value: lhs & rhs, loc: value.loc}; |
| 398 | } |
| 399 | break; |
| 400 | } |
| 401 | case '^': { |
| 402 | if (typeof lhs === 'number' && typeof rhs === 'number') { |
| 403 | result = {kind: 'Primitive', value: lhs ^ rhs, loc: value.loc}; |
| 404 | } |
| 405 | break; |
| 406 | } |
| 407 | case '<<': { |
| 408 | if (typeof lhs === 'number' && typeof rhs === 'number') { |
| 409 | result = {kind: 'Primitive', value: lhs << rhs, loc: value.loc}; |
| 410 | } |
| 411 | break; |
| 412 | } |
| 413 | case '>>': { |
| 414 | if (typeof lhs === 'number' && typeof rhs === 'number') { |
| 415 | result = {kind: 'Primitive', value: lhs >> rhs, loc: value.loc}; |
| 416 | } |
| 417 | break; |
| 418 | } |
| 419 | case '>>>': { |
| 420 | if (typeof lhs === 'number' && typeof rhs === 'number') { |
| 421 | result = { |
| 422 | kind: 'Primitive', |
| 423 | value: lhs >>> rhs, |
| 424 | loc: value.loc, |
| 425 | }; |
| 426 | } |
| 427 | break; |
| 428 | } |
| 429 | case '%': { |
| 430 | if (typeof lhs === 'number' && typeof rhs === 'number') { |
| 431 | result = {kind: 'Primitive', value: lhs % rhs, loc: value.loc}; |
| 432 | } |
| 433 | break; |
| 434 | } |
| 435 | case '**': { |
| 436 | if (typeof lhs === 'number' && typeof rhs === 'number') { |
| 437 | result = {kind: 'Primitive', value: lhs ** rhs, loc: value.loc}; |
| 438 | } |
| 439 | break; |
| 440 | } |
| 441 | case '<': { |
| 442 | if (typeof lhs === 'number' && typeof rhs === 'number') { |
| 443 | result = {kind: 'Primitive', value: lhs < rhs, loc: value.loc}; |
| 444 | } |
| 445 | break; |
| 446 | } |
| 447 | case '<=': { |
| 448 | if (typeof lhs === 'number' && typeof rhs === 'number') { |
| 449 | result = {kind: 'Primitive', value: lhs <= rhs, loc: value.loc}; |
| 450 | } |
| 451 | break; |
| 452 | } |
| 453 | case '>': { |
| 454 | if (typeof lhs === 'number' && typeof rhs === 'number') { |
| 455 | result = {kind: 'Primitive', value: lhs > rhs, loc: value.loc}; |
| 456 | } |
| 457 | break; |
| 458 | } |
| 459 | case '>=': { |
| 460 | if (typeof lhs === 'number' && typeof rhs === 'number') { |
| 461 | result = {kind: 'Primitive', value: lhs >= rhs, loc: value.loc}; |
| 462 | } |
| 463 | break; |
| 464 | } |
| 465 | case '==': { |
| 466 | result = {kind: 'Primitive', value: lhs == rhs, loc: value.loc}; |
| 467 | break; |
| 468 | } |
| 469 | case '===': { |
| 470 | result = {kind: 'Primitive', value: lhs === rhs, loc: value.loc}; |
| 471 | break; |
| 472 | } |
| 473 | case '!=': { |
| 474 | result = {kind: 'Primitive', value: lhs != rhs, loc: value.loc}; |
| 475 | break; |
| 476 | } |
| 477 | case '!==': { |
| 478 | result = {kind: 'Primitive', value: lhs !== rhs, loc: value.loc}; |
| 479 | break; |
| 480 | } |
| 481 | default: { |
| 482 | break; |
| 483 | } |
| 484 | } |
| 485 | if (result !== null) { |
| 486 | instr.value = result; |
| 487 | return result; |
| 488 | } |
| 489 | } |
| 490 | return null; |
| 491 | } |
| 492 | case 'PropertyLoad': { |
| 493 | const objectValue = read(constants, value.object); |
| 494 | if (objectValue !== null) { |
| 495 | if ( |
| 496 | objectValue.kind === 'Primitive' && |
| 497 | typeof objectValue.value === 'string' && |
| 498 | value.property === 'length' |
| 499 | ) { |
| 500 | const result: InstructionValue = { |
| 501 | kind: 'Primitive', |
| 502 | value: objectValue.value.length, |
| 503 | loc: value.loc, |
| 504 | }; |
| 505 | instr.value = result; |
| 506 | return result; |
| 507 | } |
| 508 | } |
| 509 | return null; |
| 510 | } |
| 511 | case 'TemplateLiteral': { |
| 512 | if (value.subexprs.length === 0) { |
| 513 | const result: InstructionValue = { |
| 514 | kind: 'Primitive', |
| 515 | value: value.quasis.map(q => q.cooked).join(''), |
| 516 | loc: value.loc, |
| 517 | }; |
| 518 | instr.value = result; |
| 519 | return result; |
| 520 | } |
| 521 | |
| 522 | if (value.subexprs.length !== value.quasis.length - 1) { |
| 523 | return null; |
| 524 | } |
| 525 | |
| 526 | if (value.quasis.some(q => q.cooked === undefined)) { |
| 527 | return null; |
| 528 | } |
| 529 | |
| 530 | let quasiIndex = 0; |
| 531 | let resultString = value.quasis[quasiIndex].cooked as string; |
| 532 | ++quasiIndex; |
| 533 | |
| 534 | for (const subExpr of value.subexprs) { |
| 535 | const subExprValue = read(constants, subExpr); |
| 536 | if (!subExprValue || subExprValue.kind !== 'Primitive') { |
| 537 | return null; |
| 538 | } |
| 539 | |
| 540 | const expressionValue = subExprValue.value; |
| 541 | if ( |
| 542 | typeof expressionValue !== 'number' && |
| 543 | typeof expressionValue !== 'string' && |
| 544 | typeof expressionValue !== 'boolean' && |
| 545 | !(typeof expressionValue === 'object' && expressionValue === null) |
| 546 | ) { |
| 547 | // value is not supported (function, object) or invalid (symbol), or something else |
| 548 | return null; |
| 549 | } |
| 550 | |
| 551 | const suffix = value.quasis[quasiIndex].cooked; |
| 552 | ++quasiIndex; |
| 553 | |
| 554 | if (suffix === undefined) { |
| 555 | return null; |
| 556 | } |
| 557 | |
| 558 | /* |
| 559 | * Spec states that concat calls ToString(argument) internally on its parameters |
| 560 | * -> we don't have to implement ToString(argument) ourselves and just use the engine implementation |
| 561 | * Refs: |
| 562 | * - https://tc39.es/ecma262/2024/#sec-tostring |
| 563 | * - https://tc39.es/ecma262/2024/#sec-string.prototype.concat |
| 564 | * - https://tc39.es/ecma262/2024/#sec-template-literals-runtime-semantics-evaluation |
| 565 | */ |
| 566 | resultString = resultString.concat(expressionValue as string, suffix); |
| 567 | } |
| 568 | |
| 569 | const result: InstructionValue = { |
| 570 | kind: 'Primitive', |
| 571 | value: resultString, |
| 572 | loc: value.loc, |
| 573 | }; |
| 574 | |
| 575 | instr.value = result; |
| 576 | return result; |
| 577 | } |
| 578 | case 'LoadLocal': { |
| 579 | const placeValue = read(constants, value.place); |
| 580 | if (placeValue !== null) { |
| 581 | instr.value = placeValue; |
| 582 | } |
| 583 | return placeValue; |
| 584 | } |
| 585 | case 'StoreLocal': { |
| 586 | const placeValue = read(constants, value.value); |
| 587 | if (placeValue !== null) { |
| 588 | constants.set(value.lvalue.place.identifier.id, placeValue); |
| 589 | } |
| 590 | return placeValue; |
| 591 | } |
| 592 | case 'ObjectMethod': |
| 593 | case 'FunctionExpression': { |
| 594 | constantPropagationImpl(value.loweredFunc.func, constants); |
| 595 | return null; |
| 596 | } |
| 597 | case 'StartMemoize': { |
| 598 | if (value.deps != null) { |
| 599 | for (const dep of value.deps) { |
| 600 | if (dep.root.kind === 'NamedLocal') { |
| 601 | const placeValue = read(constants, dep.root.value); |
| 602 | if (placeValue != null && placeValue.kind === 'Primitive') { |
| 603 | dep.root.constant = true; |
| 604 | } |
| 605 | } |
| 606 | } |
| 607 | } |
| 608 | return null; |
| 609 | } |
| 610 | default: { |
| 611 | // TODO: handle more cases |
| 612 | return null; |
| 613 | } |
| 614 | } |
| 615 | } |
| 616 | |
| 617 | /* |
| 618 | * Recursively read the value of a place: if it is a constant place, attempt to read |
| 619 | * from that place until reaching a primitive or finding a value that is unset. |
| 620 | */ |
| 621 | function read(constants: Constants, place: Place): Constant | null { |
| 622 | return constants.get(place.identifier.id) ?? null; |
| 623 | } |
| 624 | |
| 625 | type Constant = Primitive | LoadGlobal; |
| 626 | type Constants = Map<IdentifierId, Constant>; |