| 1 | // Copyright (c) Meta Platforms, Inc. and affiliates. |
| 2 | // |
| 3 | // This source code is licensed under the MIT license found in the |
| 4 | // LICENSE file in the root directory of this source tree. |
| 5 | |
| 6 | //! Constant propagation/folding pass. |
| 7 | //! |
| 8 | //! Applies Sparse Conditional Constant Propagation to the given function. |
| 9 | //! We use abstract interpretation to record known constant values for identifiers, |
| 10 | //! with lack of a value indicating that the identifier does not have a known |
| 11 | //! constant value. |
| 12 | //! |
| 13 | //! Instructions which can be compile-time evaluated *and* whose operands are known |
| 14 | //! constants are replaced with the resulting constant value. |
| 15 | //! |
| 16 | //! This pass also exploits SSA form, tracking constant values of local variables. |
| 17 | //! For example, in `let x = 4; let y = x + 1` we know that `x = 4` in the binary |
| 18 | //! expression and can replace it with `Constant 5`. |
| 19 | //! |
| 20 | //! This pass also visits conditionals (currently only IfTerminal) and can prune |
| 21 | //! unreachable branches when the condition is a known truthy/falsey constant. |
| 22 | //! The pass uses fixpoint iteration, looping until no additional updates can be |
| 23 | //! performed. |
| 24 | //! |
| 25 | //! Analogous to TS `Optimization/ConstantPropagation.ts`. |
| 26 | |
| 27 | use rustc_hash::FxHashMap; |
| 28 | |
| 29 | use react_compiler_diagnostics::JsString; |
| 30 | use react_compiler_hir::environment::Environment; |
| 31 | use react_compiler_hir::{ |
| 32 | BinaryOperator, BlockKind, FloatValue, FunctionId, GotoVariant, HirFunction, IdentifierId, |
| 33 | InstructionValue, NonLocalBinding, Phi, Place, PrimitiveValue, PropertyLiteral, SourceLocation, |
| 34 | Terminal, UnaryOperator, UpdateOperator, format_js_number, |
| 35 | }; |
| 36 | use react_compiler_lowering::{ |
| 37 | get_reverse_postordered_blocks, mark_instruction_ids, mark_predecessors, |
| 38 | remove_dead_do_while_statements, remove_unnecessary_try_catch, remove_unreachable_for_updates, |
| 39 | }; |
| 40 | use react_compiler_ssa::enter_ssa::placeholder_function; |
| 41 | |
| 42 | use crate::merge_consecutive_blocks::merge_consecutive_blocks; |
| 43 | |
| 44 | // ============================================================================= |
| 45 | // Constant type — mirrors TS `type Constant = Primitive | LoadGlobal` |
| 46 | // The loc is preserved so that when we replace an instruction value with the |
| 47 | // constant, we use the loc from the original definition site (matching TS). |
| 48 | // ============================================================================= |
| 49 | |
| 50 | #[derive(Debug, Clone)] |
| 51 | enum Constant { |
| 52 | Primitive { |
| 53 | value: PrimitiveValue, |
| 54 | loc: Option<SourceLocation>, |
| 55 | }, |
| 56 | LoadGlobal { |
| 57 | binding: NonLocalBinding, |
| 58 | loc: Option<SourceLocation>, |
| 59 | }, |
| 60 | } |
| 61 | |
| 62 | impl Constant { |
| 63 | fn into_instruction_value(self) -> InstructionValue { |
| 64 | match self { |
| 65 | Constant::Primitive { value, loc } => InstructionValue::Primitive { value, loc }, |
| 66 | Constant::LoadGlobal { binding, loc } => InstructionValue::LoadGlobal { binding, loc }, |
| 67 | } |
| 68 | } |
| 69 | } |
| 70 | |
| 71 | /// Map of known constant values. Uses FxHashMap (not IndexMap) since iteration |
| 72 | /// order does not affect correctness — this map is only used for lookups. |
| 73 | type Constants = FxHashMap<IdentifierId, Constant>; |
| 74 | |
| 75 | // ============================================================================= |
| 76 | // Public entry point |
| 77 | // ============================================================================= |
| 78 | |
| 79 | pub fn constant_propagation(func: &mut HirFunction, env: &mut Environment) { |
| 80 | let mut constants: Constants = FxHashMap::default(); |
| 81 | constant_propagation_impl(func, env, &mut constants); |
| 82 | } |
| 83 | |
| 84 | fn constant_propagation_impl( |
| 85 | func: &mut HirFunction, |
| 86 | env: &mut Environment, |
| 87 | constants: &mut Constants, |
| 88 | ) { |
| 89 | loop { |
| 90 | let have_terminals_changed = apply_constant_propagation(func, env, constants); |
| 91 | if !have_terminals_changed { |
| 92 | break; |
| 93 | } |
| 94 | /* |
| 95 | * If terminals have changed then blocks may have become newly unreachable. |
| 96 | * Re-run minification of the graph (incl reordering instruction ids) |
| 97 | */ |
| 98 | func.body.blocks = get_reverse_postordered_blocks(&func.body, &func.instructions); |
| 99 | remove_unreachable_for_updates(&mut func.body); |
| 100 | remove_dead_do_while_statements(&mut func.body); |
| 101 | remove_unnecessary_try_catch(&mut func.body); |
| 102 | mark_instruction_ids(&mut func.body, &mut func.instructions); |
| 103 | mark_predecessors(&mut func.body); |
| 104 | |
| 105 | // Now that predecessors are updated, prune phi operands that can never be reached |
| 106 | for (_block_id, block) in func.body.blocks.iter_mut() { |
| 107 | for phi in &mut block.phis { |
| 108 | phi.operands |
| 109 | .retain(|pred, _operand| block.preds.contains(pred)); |
| 110 | } |
| 111 | } |
| 112 | |
| 113 | /* |
| 114 | * By removing some phi operands, there may be phis that were not previously |
| 115 | * redundant but now are |
| 116 | */ |
| 117 | react_compiler_ssa::eliminate_redundant_phi(func, env); |
| 118 | |
| 119 | /* |
| 120 | * Finally, merge together any blocks that are now guaranteed to execute |
| 121 | * consecutively |
| 122 | */ |
| 123 | merge_consecutive_blocks(func, &mut env.functions); |
| 124 | |
| 125 | // TODO: port assertConsistentIdentifiers(fn) and assertTerminalSuccessorsExist(fn) |
| 126 | // from TS HIR validation. These are debug assertions that verify structural |
| 127 | // invariants after the CFG cleanup helpers run. |
| 128 | } |
| 129 | } |
| 130 | |
| 131 | fn apply_constant_propagation( |
| 132 | func: &mut HirFunction, |
| 133 | env: &mut Environment, |
| 134 | constants: &mut Constants, |
| 135 | ) -> bool { |
| 136 | let mut has_changes = false; |
| 137 | |
| 138 | let block_ids: Vec<_> = func.body.blocks.keys().copied().collect(); |
| 139 | for block_id in block_ids { |
| 140 | let block = &func.body.blocks[&block_id]; |
| 141 | |
| 142 | // Initialize phi values if all operands have the same known constant value |
| 143 | let phi_updates: Vec<(IdentifierId, Constant)> = block |
| 144 | .phis |
| 145 | .iter() |
| 146 | .filter_map(|phi| { |
| 147 | let value = evaluate_phi(phi, constants)?; |
| 148 | Some((phi.place.identifier, value)) |
| 149 | }) |
| 150 | .collect(); |
| 151 | for (id, value) in phi_updates { |
| 152 | constants.insert(id, value); |
| 153 | } |
| 154 | |
| 155 | let block = &func.body.blocks[&block_id]; |
| 156 | let instr_ids = block.instructions.clone(); |
| 157 | let block_kind = block.kind; |
| 158 | let instr_count = instr_ids.len(); |
| 159 | |
| 160 | for (i, instr_id) in instr_ids.iter().enumerate() { |
| 161 | if block_kind == BlockKind::Sequence && i == instr_count - 1 { |
| 162 | /* |
| 163 | * evaluating the last value of a value block can break order of evaluation, |
| 164 | * skip these instructions |
| 165 | */ |
| 166 | continue; |
| 167 | } |
| 168 | let result = evaluate_instruction(constants, func, env, *instr_id); |
| 169 | if let Some(value) = result { |
| 170 | let lvalue_id = func.instructions[instr_id.0 as usize].lvalue.identifier; |
| 171 | constants.insert(lvalue_id, value); |
| 172 | } |
| 173 | } |
| 174 | |
| 175 | let block = &func.body.blocks[&block_id]; |
| 176 | match &block.terminal { |
| 177 | Terminal::If { |
| 178 | test, |
| 179 | consequent, |
| 180 | alternate, |
| 181 | id, |
| 182 | loc, |
| 183 | .. |
| 184 | } => { |
| 185 | let test_value = read(constants, test); |
| 186 | if let Some(Constant::Primitive { |
| 187 | value: ref prim, .. |
| 188 | }) = test_value |
| 189 | { |
| 190 | has_changes = true; |
| 191 | let target_block_id = if is_truthy(prim) { |
| 192 | *consequent |
| 193 | } else { |
| 194 | *alternate |
| 195 | }; |
| 196 | let terminal = Terminal::Goto { |
| 197 | variant: GotoVariant::Break, |
| 198 | block: target_block_id, |
| 199 | id: *id, |
| 200 | loc: *loc, |
| 201 | }; |
| 202 | func.body.blocks.get_mut(&block_id).unwrap().terminal = terminal; |
| 203 | } |
| 204 | } |
| 205 | Terminal::Unsupported { .. } |
| 206 | | Terminal::Unreachable { .. } |
| 207 | | Terminal::Throw { .. } |
| 208 | | Terminal::Return { .. } |
| 209 | | Terminal::Goto { .. } |
| 210 | | Terminal::Branch { .. } |
| 211 | | Terminal::Switch { .. } |
| 212 | | Terminal::DoWhile { .. } |
| 213 | | Terminal::While { .. } |
| 214 | | Terminal::For { .. } |
| 215 | | Terminal::ForOf { .. } |
| 216 | | Terminal::ForIn { .. } |
| 217 | | Terminal::Logical { .. } |
| 218 | | Terminal::Ternary { .. } |
| 219 | | Terminal::Optional { .. } |
| 220 | | Terminal::Label { .. } |
| 221 | | Terminal::Sequence { .. } |
| 222 | | Terminal::MaybeThrow { .. } |
| 223 | | Terminal::Try { .. } |
| 224 | | Terminal::Scope { .. } |
| 225 | | Terminal::PrunedScope { .. } => { |
| 226 | // no-op |
| 227 | } |
| 228 | } |
| 229 | } |
| 230 | |
| 231 | has_changes |
| 232 | } |
| 233 | |
| 234 | // ============================================================================= |
| 235 | // Phi evaluation |
| 236 | // ============================================================================= |
| 237 | |
| 238 | fn evaluate_phi(phi: &Phi, constants: &Constants) -> Option<Constant> { |
| 239 | let mut value: Option<Constant> = None; |
| 240 | for (_pred, operand) in &phi.operands { |
| 241 | let operand_value = constants.get(&operand.identifier)?; |
| 242 | |
| 243 | match &value { |
| 244 | None => { |
| 245 | // first iteration of the loop |
| 246 | value = Some(operand_value.clone()); |
| 247 | continue; |
| 248 | } |
| 249 | Some(current) => match (current, operand_value) { |
| 250 | (Constant::Primitive { value: a, .. }, Constant::Primitive { value: b, .. }) => { |
| 251 | // Use JS strict equality semantics: NaN !== NaN |
| 252 | if !js_strict_equal(a, b) { |
| 253 | return None; |
| 254 | } |
| 255 | } |
| 256 | ( |
| 257 | Constant::LoadGlobal { binding: a, .. }, |
| 258 | Constant::LoadGlobal { binding: b, .. }, |
| 259 | ) => { |
| 260 | // different global values, can't constant propagate |
| 261 | if a.name() != b.name() { |
| 262 | return None; |
| 263 | } |
| 264 | } |
| 265 | // found different kinds of constants, can't constant propagate |
| 266 | (Constant::Primitive { .. }, Constant::LoadGlobal { .. }) |
| 267 | | (Constant::LoadGlobal { .. }, Constant::Primitive { .. }) => { |
| 268 | return None; |
| 269 | } |
| 270 | }, |
| 271 | } |
| 272 | } |
| 273 | value |
| 274 | } |
| 275 | |
| 276 | // ============================================================================= |
| 277 | // Instruction evaluation |
| 278 | // ============================================================================= |
| 279 | |
| 280 | fn evaluate_instruction( |
| 281 | constants: &mut Constants, |
| 282 | func: &mut HirFunction, |
| 283 | env: &mut Environment, |
| 284 | instr_id: react_compiler_hir::InstructionId, |
| 285 | ) -> Option<Constant> { |
| 286 | let instr = &func.instructions[instr_id.0 as usize]; |
| 287 | match &instr.value { |
| 288 | InstructionValue::Primitive { value, loc } => Some(Constant::Primitive { |
| 289 | value: value.clone(), |
| 290 | loc: *loc, |
| 291 | }), |
| 292 | InstructionValue::LoadGlobal { binding, loc } => Some(Constant::LoadGlobal { |
| 293 | binding: binding.clone(), |
| 294 | loc: *loc, |
| 295 | }), |
| 296 | InstructionValue::ComputedLoad { |
| 297 | object, |
| 298 | property, |
| 299 | loc, |
| 300 | } => { |
| 301 | let prop_value = read(constants, property); |
| 302 | if let Some(Constant::Primitive { |
| 303 | value: ref prim, .. |
| 304 | }) = prop_value |
| 305 | { |
| 306 | match prim { |
| 307 | PrimitiveValue::String(s) if s.as_str().is_some_and(is_valid_identifier) => { |
| 308 | let object = object.clone(); |
| 309 | let loc = *loc; |
| 310 | let new_property = |
| 311 | PropertyLiteral::String(s.as_str().expect("guarded utf8").to_string()); |
| 312 | func.instructions[instr_id.0 as usize].value = |
| 313 | InstructionValue::PropertyLoad { |
| 314 | object, |
| 315 | property: new_property, |
| 316 | loc, |
| 317 | }; |
| 318 | } |
| 319 | PrimitiveValue::Number(n) => { |
| 320 | let object = object.clone(); |
| 321 | let loc = *loc; |
| 322 | let new_property = PropertyLiteral::Number(*n); |
| 323 | func.instructions[instr_id.0 as usize].value = |
| 324 | InstructionValue::PropertyLoad { |
| 325 | object, |
| 326 | property: new_property, |
| 327 | loc, |
| 328 | }; |
| 329 | } |
| 330 | PrimitiveValue::Null |
| 331 | | PrimitiveValue::Undefined |
| 332 | | PrimitiveValue::Boolean(_) |
| 333 | | PrimitiveValue::String(_) => {} |
| 334 | } |
| 335 | } |
| 336 | None |
| 337 | } |
| 338 | InstructionValue::ComputedStore { |
| 339 | object, |
| 340 | property, |
| 341 | value, |
| 342 | loc, |
| 343 | } => { |
| 344 | let prop_value = read(constants, property); |
| 345 | if let Some(Constant::Primitive { |
| 346 | value: ref prim, .. |
| 347 | }) = prop_value |
| 348 | { |
| 349 | match prim { |
| 350 | PrimitiveValue::String(s) if s.as_str().is_some_and(is_valid_identifier) => { |
| 351 | let object = object.clone(); |
| 352 | let store_value = value.clone(); |
| 353 | let loc = *loc; |
| 354 | let new_property = |
| 355 | PropertyLiteral::String(s.as_str().expect("guarded utf8").to_string()); |
| 356 | func.instructions[instr_id.0 as usize].value = |
| 357 | InstructionValue::PropertyStore { |
| 358 | object, |
| 359 | property: new_property, |
| 360 | value: store_value, |
| 361 | loc, |
| 362 | }; |
| 363 | } |
| 364 | PrimitiveValue::Number(n) => { |
| 365 | let object = object.clone(); |
| 366 | let store_value = value.clone(); |
| 367 | let loc = *loc; |
| 368 | let new_property = PropertyLiteral::Number(*n); |
| 369 | func.instructions[instr_id.0 as usize].value = |
| 370 | InstructionValue::PropertyStore { |
| 371 | object, |
| 372 | property: new_property, |
| 373 | value: store_value, |
| 374 | loc, |
| 375 | }; |
| 376 | } |
| 377 | PrimitiveValue::Null |
| 378 | | PrimitiveValue::Undefined |
| 379 | | PrimitiveValue::Boolean(_) |
| 380 | | PrimitiveValue::String(_) => {} |
| 381 | } |
| 382 | } |
| 383 | None |
| 384 | } |
| 385 | InstructionValue::PostfixUpdate { |
| 386 | lvalue, |
| 387 | operation, |
| 388 | value, |
| 389 | loc, |
| 390 | } => { |
| 391 | let previous = read(constants, value); |
| 392 | if let Some(Constant::Primitive { |
| 393 | value: PrimitiveValue::Number(n), |
| 394 | loc: prev_loc, |
| 395 | }) = previous |
| 396 | { |
| 397 | let prev_val = n.value(); |
| 398 | let next_val = match operation { |
| 399 | UpdateOperator::Increment => prev_val + 1.0, |
| 400 | UpdateOperator::Decrement => prev_val - 1.0, |
| 401 | }; |
| 402 | // Store the updated value for the lvalue |
| 403 | let lvalue_id = lvalue.identifier; |
| 404 | constants.insert( |
| 405 | lvalue_id, |
| 406 | Constant::Primitive { |
| 407 | value: PrimitiveValue::Number(FloatValue::new(next_val)), |
| 408 | loc: *loc, |
| 409 | }, |
| 410 | ); |
| 411 | // But return the value prior to the update (preserving its original loc) |
| 412 | return Some(Constant::Primitive { |
| 413 | value: PrimitiveValue::Number(n), |
| 414 | loc: prev_loc, |
| 415 | }); |
| 416 | } |
| 417 | None |
| 418 | } |
| 419 | InstructionValue::PrefixUpdate { |
| 420 | lvalue, |
| 421 | operation, |
| 422 | value, |
| 423 | loc, |
| 424 | } => { |
| 425 | let previous = read(constants, value); |
| 426 | if let Some(Constant::Primitive { |
| 427 | value: PrimitiveValue::Number(n), |
| 428 | .. |
| 429 | }) = previous |
| 430 | { |
| 431 | let prev_val = n.value(); |
| 432 | let next_val = match operation { |
| 433 | UpdateOperator::Increment => prev_val + 1.0, |
| 434 | UpdateOperator::Decrement => prev_val - 1.0, |
| 435 | }; |
| 436 | let result = Constant::Primitive { |
| 437 | value: PrimitiveValue::Number(FloatValue::new(next_val)), |
| 438 | loc: *loc, |
| 439 | }; |
| 440 | // Store and return the updated value |
| 441 | let lvalue_id = lvalue.identifier; |
| 442 | constants.insert(lvalue_id, result.clone()); |
| 443 | return Some(result); |
| 444 | } |
| 445 | None |
| 446 | } |
| 447 | InstructionValue::UnaryExpression { |
| 448 | operator, |
| 449 | value, |
| 450 | loc, |
| 451 | } => match operator { |
| 452 | UnaryOperator::Not => { |
| 453 | let operand = read(constants, value); |
| 454 | if let Some(Constant::Primitive { |
| 455 | value: ref prim, .. |
| 456 | }) = operand |
| 457 | { |
| 458 | let negated = !is_truthy(prim); |
| 459 | let loc = *loc; |
| 460 | let result = Constant::Primitive { |
| 461 | value: PrimitiveValue::Boolean(negated), |
| 462 | loc, |
| 463 | }; |
| 464 | func.instructions[instr_id.0 as usize].value = InstructionValue::Primitive { |
| 465 | value: PrimitiveValue::Boolean(negated), |
| 466 | loc, |
| 467 | }; |
| 468 | return Some(result); |
| 469 | } |
| 470 | None |
| 471 | } |
| 472 | UnaryOperator::Minus => { |
| 473 | let operand = read(constants, value); |
| 474 | if let Some(Constant::Primitive { |
| 475 | value: PrimitiveValue::Number(n), |
| 476 | .. |
| 477 | }) = operand |
| 478 | { |
| 479 | let negated = n.value() * -1.0; |
| 480 | let loc = *loc; |
| 481 | let result = Constant::Primitive { |
| 482 | value: PrimitiveValue::Number(FloatValue::new(negated)), |
| 483 | loc, |
| 484 | }; |
| 485 | func.instructions[instr_id.0 as usize].value = InstructionValue::Primitive { |
| 486 | value: PrimitiveValue::Number(FloatValue::new(negated)), |
| 487 | loc, |
| 488 | }; |
| 489 | return Some(result); |
| 490 | } |
| 491 | None |
| 492 | } |
| 493 | UnaryOperator::Plus |
| 494 | | UnaryOperator::BitwiseNot |
| 495 | | UnaryOperator::TypeOf |
| 496 | | UnaryOperator::Void => None, |
| 497 | }, |
| 498 | InstructionValue::BinaryExpression { |
| 499 | operator, |
| 500 | left, |
| 501 | right, |
| 502 | loc, |
| 503 | } => { |
| 504 | let lhs_value = read(constants, left); |
| 505 | let rhs_value = read(constants, right); |
| 506 | if let ( |
| 507 | Some(Constant::Primitive { value: lhs, .. }), |
| 508 | Some(Constant::Primitive { value: rhs, .. }), |
| 509 | ) = (&lhs_value, &rhs_value) |
| 510 | { |
| 511 | let result = evaluate_binary_op(*operator, lhs, rhs); |
| 512 | if let Some(ref prim) = result { |
| 513 | let loc = *loc; |
| 514 | func.instructions[instr_id.0 as usize].value = InstructionValue::Primitive { |
| 515 | value: prim.clone(), |
| 516 | loc, |
| 517 | }; |
| 518 | return Some(Constant::Primitive { |
| 519 | value: prim.clone(), |
| 520 | loc, |
| 521 | }); |
| 522 | } |
| 523 | } |
| 524 | None |
| 525 | } |
| 526 | InstructionValue::PropertyLoad { |
| 527 | object, |
| 528 | property, |
| 529 | loc, |
| 530 | } => { |
| 531 | let object_value = read(constants, object); |
| 532 | if let Some(Constant::Primitive { |
| 533 | value: PrimitiveValue::String(ref s), |
| 534 | .. |
| 535 | }) = object_value |
| 536 | { |
| 537 | if let PropertyLiteral::String(prop_name) = property { |
| 538 | if prop_name == "length" { |
| 539 | // Use UTF-16 code unit count to match JS .length semantics |
| 540 | let len = s.len_utf16() as f64; |
| 541 | let loc = *loc; |
| 542 | let result = Constant::Primitive { |
| 543 | value: PrimitiveValue::Number(FloatValue::new(len)), |
| 544 | loc, |
| 545 | }; |
| 546 | func.instructions[instr_id.0 as usize].value = |
| 547 | InstructionValue::Primitive { |
| 548 | value: PrimitiveValue::Number(FloatValue::new(len)), |
| 549 | loc, |
| 550 | }; |
| 551 | return Some(result); |
| 552 | } |
| 553 | } |
| 554 | } |
| 555 | None |
| 556 | } |
| 557 | InstructionValue::TemplateLiteral { |
| 558 | subexprs, |
| 559 | quasis, |
| 560 | loc, |
| 561 | } => { |
| 562 | if subexprs.is_empty() { |
| 563 | // No subexpressions: join all cooked quasis |
| 564 | let mut result_string = String::new(); |
| 565 | for q in quasis { |
| 566 | match &q.cooked { |
| 567 | Some(cooked) => result_string.push_str(cooked), |
| 568 | None => return None, |
| 569 | } |
| 570 | } |
| 571 | let loc = *loc; |
| 572 | let result = Constant::Primitive { |
| 573 | value: PrimitiveValue::String(JsString::from_marker_string(&result_string)), |
| 574 | loc, |
| 575 | }; |
| 576 | func.instructions[instr_id.0 as usize].value = InstructionValue::Primitive { |
| 577 | value: PrimitiveValue::String(JsString::from_marker_string(&result_string)), |
| 578 | loc, |
| 579 | }; |
| 580 | return Some(result); |
| 581 | } |
| 582 | |
| 583 | if subexprs.len() != quasis.len() - 1 { |
| 584 | return None; |
| 585 | } |
| 586 | |
| 587 | if quasis.iter().any(|q| q.cooked.is_none()) { |
| 588 | return None; |
| 589 | } |
| 590 | |
| 591 | let mut quasi_index = 0usize; |
| 592 | let mut result_string = quasis[quasi_index].cooked.as_ref().unwrap().clone(); |
| 593 | quasi_index += 1; |
| 594 | |
| 595 | for sub_expr in subexprs { |
| 596 | let sub_expr_value = read(constants, sub_expr); |
| 597 | let sub_prim = match sub_expr_value { |
| 598 | Some(Constant::Primitive { ref value, .. }) => value, |
| 599 | _ => return None, |
| 600 | }; |
| 601 | |
| 602 | let expression_str = match sub_prim { |
| 603 | PrimitiveValue::Null => "null".to_string(), |
| 604 | PrimitiveValue::Boolean(b) => b.to_string(), |
| 605 | PrimitiveValue::Number(n) => format_js_number(n.value()), |
| 606 | PrimitiveValue::String(s) => s.to_marker_string(), |
| 607 | // TS rejects undefined subexpression values |
| 608 | PrimitiveValue::Undefined => return None, |
| 609 | }; |
| 610 | |
| 611 | let suffix = match &quasis[quasi_index].cooked { |
| 612 | Some(s) => s.clone(), |
| 613 | None => return None, |
| 614 | }; |
| 615 | quasi_index += 1; |
| 616 | |
| 617 | result_string.push_str(&expression_str); |
| 618 | result_string.push_str(&suffix); |
| 619 | } |
| 620 | |
| 621 | let loc = *loc; |
| 622 | let result = Constant::Primitive { |
| 623 | value: PrimitiveValue::String(JsString::from_marker_string(&result_string)), |
| 624 | loc, |
| 625 | }; |
| 626 | func.instructions[instr_id.0 as usize].value = InstructionValue::Primitive { |
| 627 | value: PrimitiveValue::String(JsString::from_marker_string(&result_string)), |
| 628 | loc, |
| 629 | }; |
| 630 | Some(result) |
| 631 | } |
| 632 | InstructionValue::LoadLocal { place, .. } => { |
| 633 | let place_value = read(constants, place); |
| 634 | if let Some(ref constant) = place_value { |
| 635 | // Replace the LoadLocal with the constant value (including the constant's original loc) |
| 636 | func.instructions[instr_id.0 as usize].value = |
| 637 | constant.clone().into_instruction_value(); |
| 638 | } |
| 639 | place_value |
| 640 | } |
| 641 | InstructionValue::StoreLocal { lvalue, value, .. } => { |
| 642 | let place_value = read(constants, value); |
| 643 | if let Some(ref constant) = place_value { |
| 644 | let lvalue_id = lvalue.place.identifier; |
| 645 | constants.insert(lvalue_id, constant.clone()); |
| 646 | } |
| 647 | place_value |
| 648 | } |
| 649 | InstructionValue::FunctionExpression { lowered_func, .. } => { |
| 650 | let func_id = lowered_func.func; |
| 651 | process_inner_function(func_id, env, constants); |
| 652 | None |
| 653 | } |
| 654 | InstructionValue::ObjectMethod { lowered_func, .. } => { |
| 655 | let func_id = lowered_func.func; |
| 656 | process_inner_function(func_id, env, constants); |
| 657 | None |
| 658 | } |
| 659 | InstructionValue::StartMemoize { deps, .. } => { |
| 660 | if let Some(deps) = deps { |
| 661 | // Two-phase: collect which deps are constant, then mutate |
| 662 | let const_dep_indices: Vec<usize> = deps |
| 663 | .iter() |
| 664 | .enumerate() |
| 665 | .filter_map(|(i, dep)| { |
| 666 | if let react_compiler_hir::ManualMemoDependencyRoot::NamedLocal { |
| 667 | value, |
| 668 | .. |
| 669 | } = &dep.root |
| 670 | { |
| 671 | let pv = read(constants, value); |
| 672 | if matches!(pv, Some(Constant::Primitive { .. })) { |
| 673 | return Some(i); |
| 674 | } |
| 675 | } |
| 676 | None |
| 677 | }) |
| 678 | .collect(); |
| 679 | for idx in const_dep_indices { |
| 680 | if let InstructionValue::StartMemoize { |
| 681 | deps: Some(ref mut deps), |
| 682 | .. |
| 683 | } = func.instructions[instr_id.0 as usize].value |
| 684 | { |
| 685 | if let react_compiler_hir::ManualMemoDependencyRoot::NamedLocal { |
| 686 | constant, |
| 687 | .. |
| 688 | } = &mut deps[idx].root |
| 689 | { |
| 690 | *constant = true; |
| 691 | } |
| 692 | } |
| 693 | } |
| 694 | } |
| 695 | None |
| 696 | } |
| 697 | // All other instruction kinds: no constant folding |
| 698 | InstructionValue::LoadContext { .. } |
| 699 | | InstructionValue::DeclareLocal { .. } |
| 700 | | InstructionValue::DeclareContext { .. } |
| 701 | | InstructionValue::StoreContext { .. } |
| 702 | | InstructionValue::Destructure { .. } |
| 703 | | InstructionValue::JSXText { .. } |
| 704 | | InstructionValue::NewExpression { .. } |
| 705 | | InstructionValue::CallExpression { .. } |
| 706 | | InstructionValue::MethodCall { .. } |
| 707 | | InstructionValue::TypeCastExpression { .. } |
| 708 | | InstructionValue::JsxExpression { .. } |
| 709 | | InstructionValue::ObjectExpression { .. } |
| 710 | | InstructionValue::ArrayExpression { .. } |
| 711 | | InstructionValue::JsxFragment { .. } |
| 712 | | InstructionValue::RegExpLiteral { .. } |
| 713 | | InstructionValue::MetaProperty { .. } |
| 714 | | InstructionValue::PropertyStore { .. } |
| 715 | | InstructionValue::PropertyDelete { .. } |
| 716 | | InstructionValue::ComputedDelete { .. } |
| 717 | | InstructionValue::StoreGlobal { .. } |
| 718 | | InstructionValue::TaggedTemplateExpression { .. } |
| 719 | | InstructionValue::Await { .. } |
| 720 | | InstructionValue::GetIterator { .. } |
| 721 | | InstructionValue::IteratorNext { .. } |
| 722 | | InstructionValue::NextPropertyOf { .. } |
| 723 | | InstructionValue::Debugger { .. } |
| 724 | | InstructionValue::FinishMemoize { .. } |
| 725 | | InstructionValue::UnsupportedNode { .. } => None, |
| 726 | } |
| 727 | } |
| 728 | |
| 729 | // ============================================================================= |
| 730 | // Inner function processing |
| 731 | // ============================================================================= |
| 732 | |
| 733 | fn process_inner_function(func_id: FunctionId, env: &mut Environment, constants: &mut Constants) { |
| 734 | let mut inner = std::mem::replace( |
| 735 | &mut env.functions[func_id.0 as usize], |
| 736 | placeholder_function(), |
| 737 | ); |
| 738 | constant_propagation_impl(&mut inner, env, constants); |
| 739 | env.functions[func_id.0 as usize] = inner; |
| 740 | } |
| 741 | |
| 742 | // ============================================================================= |
| 743 | // Helper: read constant for a place |
| 744 | // ============================================================================= |
| 745 | |
| 746 | fn read(constants: &Constants, place: &Place) -> Option<Constant> { |
| 747 | constants.get(&place.identifier).cloned() |
| 748 | } |
| 749 | |
| 750 | // ============================================================================= |
| 751 | // Helper: is_valid_identifier |
| 752 | // ============================================================================= |
| 753 | |
| 754 | /// Check if a string is a valid JavaScript identifier. |
| 755 | /// Supports Unicode identifier characters per ECMAScript spec (ID_Start / ID_Continue). |
| 756 | /// Rejects JS reserved words (matching Babel's `isValidIdentifier` default behavior). |
| 757 | fn is_valid_identifier(s: &str) -> bool { |
| 758 | if s.is_empty() { |
| 759 | return false; |
| 760 | } |
| 761 | let mut chars = s.chars(); |
| 762 | match chars.next() { |
| 763 | Some(c) if is_id_start(c) => {} |
| 764 | _ => return false, |
| 765 | } |
| 766 | if !chars.all(is_id_continue) { |
| 767 | return false; |
| 768 | } |
| 769 | !is_reserved_word(s) |
| 770 | } |
| 771 | |
| 772 | /// JS reserved words that cannot be used as identifiers. |
| 773 | /// Includes keywords, future reserved words, and strict mode reserved words. |
| 774 | fn is_reserved_word(s: &str) -> bool { |
| 775 | matches!( |
| 776 | s, |
| 777 | "break" |
| 778 | | "case" |
| 779 | | "catch" |
| 780 | | "continue" |
| 781 | | "debugger" |
| 782 | | "default" |
| 783 | | "do" |
| 784 | | "else" |
| 785 | | "finally" |
| 786 | | "for" |
| 787 | | "function" |
| 788 | | "if" |
| 789 | | "in" |
| 790 | | "instanceof" |
| 791 | | "new" |
| 792 | | "return" |
| 793 | | "switch" |
| 794 | | "this" |
| 795 | | "throw" |
| 796 | | "try" |
| 797 | | "typeof" |
| 798 | | "var" |
| 799 | | "void" |
| 800 | | "while" |
| 801 | | "with" |
| 802 | | "class" |
| 803 | | "const" |
| 804 | | "enum" |
| 805 | | "export" |
| 806 | | "extends" |
| 807 | | "import" |
| 808 | | "super" |
| 809 | | "implements" |
| 810 | | "interface" |
| 811 | | "let" |
| 812 | | "package" |
| 813 | | "private" |
| 814 | | "protected" |
| 815 | | "public" |
| 816 | | "static" |
| 817 | | "yield" |
| 818 | | "await" |
| 819 | | "delete" |
| 820 | | "null" |
| 821 | | "true" |
| 822 | | "false" |
| 823 | ) |
| 824 | } |
| 825 | |
| 826 | /// Check if a character is valid as the start of a JS identifier (ID_Start + _ + $). |
| 827 | fn is_id_start(c: char) -> bool { |
| 828 | c == '_' || c == '$' || c.is_alphabetic() |
| 829 | } |
| 830 | |
| 831 | /// Check if a character is valid as a continuation of a JS identifier (ID_Continue + $ + \u200C + \u200D). |
| 832 | fn is_id_continue(c: char) -> bool { |
| 833 | c == '$' |
| 834 | || c == '_' |
| 835 | || c.is_alphanumeric() |
| 836 | || c == '\u{200C}' // ZWNJ |
| 837 | || c == '\u{200D}' // ZWJ |
| 838 | } |
| 839 | |
| 840 | // ============================================================================= |
| 841 | // Helper: is_truthy for PrimitiveValue |
| 842 | // ============================================================================= |
| 843 | |
| 844 | fn is_truthy(value: &PrimitiveValue) -> bool { |
| 845 | match value { |
| 846 | PrimitiveValue::Null => false, |
| 847 | PrimitiveValue::Undefined => false, |
| 848 | PrimitiveValue::Boolean(b) => *b, |
| 849 | PrimitiveValue::Number(n) => { |
| 850 | let v = n.value(); |
| 851 | v != 0.0 && !v.is_nan() |
| 852 | } |
| 853 | PrimitiveValue::String(s) => s.len_utf16() != 0, |
| 854 | } |
| 855 | } |
| 856 | |
| 857 | // ============================================================================= |
| 858 | // Binary operation evaluation |
| 859 | // ============================================================================= |
| 860 | |
| 861 | fn evaluate_binary_op( |
| 862 | operator: BinaryOperator, |
| 863 | lhs: &PrimitiveValue, |
| 864 | rhs: &PrimitiveValue, |
| 865 | ) -> Option<PrimitiveValue> { |
| 866 | match operator { |
| 867 | BinaryOperator::Add => match (lhs, rhs) { |
| 868 | (PrimitiveValue::Number(l), PrimitiveValue::Number(r)) => Some(PrimitiveValue::Number( |
| 869 | FloatValue::new(l.value() + r.value()), |
| 870 | )), |
| 871 | (PrimitiveValue::String(l), PrimitiveValue::String(r)) => { |
| 872 | // Concatenate as code units: JS `+` can pair up surrogate |
| 873 | // halves split across the operands. |
| 874 | let mut units = l.code_units(); |
| 875 | units.extend(r.code_units()); |
| 876 | Some(PrimitiveValue::String( |
| 877 | react_compiler_diagnostics::JsString::from_code_units(units), |
| 878 | )) |
| 879 | } |
| 880 | _ => None, |
| 881 | }, |
| 882 | BinaryOperator::Subtract => match (lhs, rhs) { |
| 883 | (PrimitiveValue::Number(l), PrimitiveValue::Number(r)) => Some(PrimitiveValue::Number( |
| 884 | FloatValue::new(l.value() - r.value()), |
| 885 | )), |
| 886 | _ => None, |
| 887 | }, |
| 888 | BinaryOperator::Multiply => match (lhs, rhs) { |
| 889 | (PrimitiveValue::Number(l), PrimitiveValue::Number(r)) => Some(PrimitiveValue::Number( |
| 890 | FloatValue::new(l.value() * r.value()), |
| 891 | )), |
| 892 | _ => None, |
| 893 | }, |
| 894 | BinaryOperator::Divide => match (lhs, rhs) { |
| 895 | (PrimitiveValue::Number(l), PrimitiveValue::Number(r)) => Some(PrimitiveValue::Number( |
| 896 | FloatValue::new(l.value() / r.value()), |
| 897 | )), |
| 898 | _ => None, |
| 899 | }, |
| 900 | BinaryOperator::Modulo => match (lhs, rhs) { |
| 901 | (PrimitiveValue::Number(l), PrimitiveValue::Number(r)) => Some(PrimitiveValue::Number( |
| 902 | FloatValue::new(l.value() % r.value()), |
| 903 | )), |
| 904 | _ => None, |
| 905 | }, |
| 906 | BinaryOperator::Exponent => match (lhs, rhs) { |
| 907 | (PrimitiveValue::Number(l), PrimitiveValue::Number(r)) => Some(PrimitiveValue::Number( |
| 908 | FloatValue::new(l.value().powf(r.value())), |
| 909 | )), |
| 910 | _ => None, |
| 911 | }, |
| 912 | BinaryOperator::BitwiseOr => match (lhs, rhs) { |
| 913 | (PrimitiveValue::Number(l), PrimitiveValue::Number(r)) => { |
| 914 | let result = js_to_int32(l.value()) | js_to_int32(r.value()); |
| 915 | Some(PrimitiveValue::Number(FloatValue::new(result as f64))) |
| 916 | } |
| 917 | _ => None, |
| 918 | }, |
| 919 | BinaryOperator::BitwiseAnd => match (lhs, rhs) { |
| 920 | (PrimitiveValue::Number(l), PrimitiveValue::Number(r)) => { |
| 921 | let result = js_to_int32(l.value()) & js_to_int32(r.value()); |
| 922 | Some(PrimitiveValue::Number(FloatValue::new(result as f64))) |
| 923 | } |
| 924 | _ => None, |
| 925 | }, |
| 926 | BinaryOperator::BitwiseXor => match (lhs, rhs) { |
| 927 | (PrimitiveValue::Number(l), PrimitiveValue::Number(r)) => { |
| 928 | let result = js_to_int32(l.value()) ^ js_to_int32(r.value()); |
| 929 | Some(PrimitiveValue::Number(FloatValue::new(result as f64))) |
| 930 | } |
| 931 | _ => None, |
| 932 | }, |
| 933 | BinaryOperator::ShiftLeft => match (lhs, rhs) { |
| 934 | (PrimitiveValue::Number(l), PrimitiveValue::Number(r)) => { |
| 935 | let result = js_to_int32(l.value()) << (js_to_uint32(r.value()) & 0x1f); |
| 936 | Some(PrimitiveValue::Number(FloatValue::new(result as f64))) |
| 937 | } |
| 938 | _ => None, |
| 939 | }, |
| 940 | BinaryOperator::ShiftRight => match (lhs, rhs) { |
| 941 | (PrimitiveValue::Number(l), PrimitiveValue::Number(r)) => { |
| 942 | let result = js_to_int32(l.value()) >> (js_to_uint32(r.value()) & 0x1f); |
| 943 | Some(PrimitiveValue::Number(FloatValue::new(result as f64))) |
| 944 | } |
| 945 | _ => None, |
| 946 | }, |
| 947 | BinaryOperator::UnsignedShiftRight => match (lhs, rhs) { |
| 948 | (PrimitiveValue::Number(l), PrimitiveValue::Number(r)) => { |
| 949 | let result = js_to_uint32(l.value()) >> (js_to_uint32(r.value()) & 0x1f); |
| 950 | Some(PrimitiveValue::Number(FloatValue::new(result as f64))) |
| 951 | } |
| 952 | _ => None, |
| 953 | }, |
| 954 | BinaryOperator::LessThan => match (lhs, rhs) { |
| 955 | (PrimitiveValue::Number(l), PrimitiveValue::Number(r)) => { |
| 956 | Some(PrimitiveValue::Boolean(l.value() < r.value())) |
| 957 | } |
| 958 | _ => None, |
| 959 | }, |
| 960 | BinaryOperator::LessEqual => match (lhs, rhs) { |
| 961 | (PrimitiveValue::Number(l), PrimitiveValue::Number(r)) => { |
| 962 | Some(PrimitiveValue::Boolean(l.value() <= r.value())) |
| 963 | } |
| 964 | _ => None, |
| 965 | }, |
| 966 | BinaryOperator::GreaterThan => match (lhs, rhs) { |
| 967 | (PrimitiveValue::Number(l), PrimitiveValue::Number(r)) => { |
| 968 | Some(PrimitiveValue::Boolean(l.value() > r.value())) |
| 969 | } |
| 970 | _ => None, |
| 971 | }, |
| 972 | BinaryOperator::GreaterEqual => match (lhs, rhs) { |
| 973 | (PrimitiveValue::Number(l), PrimitiveValue::Number(r)) => { |
| 974 | Some(PrimitiveValue::Boolean(l.value() >= r.value())) |
| 975 | } |
| 976 | _ => None, |
| 977 | }, |
| 978 | BinaryOperator::StrictEqual => Some(PrimitiveValue::Boolean(js_strict_equal(lhs, rhs))), |
| 979 | BinaryOperator::StrictNotEqual => Some(PrimitiveValue::Boolean(!js_strict_equal(lhs, rhs))), |
| 980 | BinaryOperator::Equal => Some(PrimitiveValue::Boolean(js_abstract_equal(lhs, rhs))), |
| 981 | BinaryOperator::NotEqual => Some(PrimitiveValue::Boolean(!js_abstract_equal(lhs, rhs))), |
| 982 | BinaryOperator::In | BinaryOperator::InstanceOf => None, |
| 983 | } |
| 984 | } |
| 985 | |
| 986 | // ============================================================================= |
| 987 | // JavaScript equality semantics |
| 988 | // ============================================================================= |
| 989 | |
| 990 | fn js_strict_equal(lhs: &PrimitiveValue, rhs: &PrimitiveValue) -> bool { |
| 991 | match (lhs, rhs) { |
| 992 | (PrimitiveValue::Null, PrimitiveValue::Null) => true, |
| 993 | (PrimitiveValue::Undefined, PrimitiveValue::Undefined) => true, |
| 994 | (PrimitiveValue::Boolean(a), PrimitiveValue::Boolean(b)) => a == b, |
| 995 | (PrimitiveValue::Number(a), PrimitiveValue::Number(b)) => { |
| 996 | let av = a.value(); |
| 997 | let bv = b.value(); |
| 998 | // NaN !== NaN in JS |
| 999 | if av.is_nan() || bv.is_nan() { |
| 1000 | return false; |
| 1001 | } |
| 1002 | av == bv |
| 1003 | } |
| 1004 | (PrimitiveValue::String(a), PrimitiveValue::String(b)) => a == b, |
| 1005 | // Different types => false |
| 1006 | _ => false, |
| 1007 | } |
| 1008 | } |
| 1009 | |
| 1010 | /// Convert a string to a number using JS `ToNumber` semantics. |
| 1011 | /// In JS: `""` → 0, `" "` → 0, `" 42 "` → 42, `"0x1A"` → 26, `"Infinity"` → Infinity. |
| 1012 | fn js_to_number(s: &str) -> f64 { |
| 1013 | let trimmed = s.trim(); |
| 1014 | if trimmed.is_empty() { |
| 1015 | return 0.0; |
| 1016 | } |
| 1017 | if trimmed == "Infinity" || trimmed == "+Infinity" { |
| 1018 | return f64::INFINITY; |
| 1019 | } |
| 1020 | if trimmed == "-Infinity" { |
| 1021 | return f64::NEG_INFINITY; |
| 1022 | } |
| 1023 | // Handle hex literals (0x/0X) |
| 1024 | if trimmed.starts_with("0x") || trimmed.starts_with("0X") { |
| 1025 | return match u64::from_str_radix(&trimmed[2..], 16) { |
| 1026 | Ok(v) => v as f64, |
| 1027 | Err(_) => f64::NAN, |
| 1028 | }; |
| 1029 | } |
| 1030 | // Handle octal literals (0o/0O) |
| 1031 | if trimmed.starts_with("0o") || trimmed.starts_with("0O") { |
| 1032 | return match u64::from_str_radix(&trimmed[2..], 8) { |
| 1033 | Ok(v) => v as f64, |
| 1034 | Err(_) => f64::NAN, |
| 1035 | }; |
| 1036 | } |
| 1037 | // Handle binary literals (0b/0B) |
| 1038 | if trimmed.starts_with("0b") || trimmed.starts_with("0B") { |
| 1039 | return match u64::from_str_radix(&trimmed[2..], 2) { |
| 1040 | Ok(v) => v as f64, |
| 1041 | Err(_) => f64::NAN, |
| 1042 | }; |
| 1043 | } |
| 1044 | trimmed.parse::<f64>().unwrap_or(f64::NAN) |
| 1045 | } |
| 1046 | |
| 1047 | fn js_abstract_equal(lhs: &PrimitiveValue, rhs: &PrimitiveValue) -> bool { |
| 1048 | match (lhs, rhs) { |
| 1049 | (PrimitiveValue::Null, PrimitiveValue::Null) => true, |
| 1050 | (PrimitiveValue::Undefined, PrimitiveValue::Undefined) => true, |
| 1051 | (PrimitiveValue::Null, PrimitiveValue::Undefined) |
| 1052 | | (PrimitiveValue::Undefined, PrimitiveValue::Null) => true, |
| 1053 | (PrimitiveValue::Boolean(a), PrimitiveValue::Boolean(b)) => a == b, |
| 1054 | (PrimitiveValue::Number(a), PrimitiveValue::Number(b)) => { |
| 1055 | let av = a.value(); |
| 1056 | let bv = b.value(); |
| 1057 | if av.is_nan() || bv.is_nan() { |
| 1058 | return false; |
| 1059 | } |
| 1060 | av == bv |
| 1061 | } |
| 1062 | (PrimitiveValue::String(a), PrimitiveValue::String(b)) => a == b, |
| 1063 | // Cross-type coercions for primitives |
| 1064 | (PrimitiveValue::Number(n), PrimitiveValue::String(s)) |
| 1065 | | (PrimitiveValue::String(s), PrimitiveValue::Number(n)) => { |
| 1066 | // String is coerced to number using JS ToNumber semantics. |
| 1067 | // Ill-formed strings coerce to NaN, like any non-numeric text. |
| 1068 | let sv = match s.as_str() { |
| 1069 | Some(utf8) => js_to_number(utf8), |
| 1070 | None => f64::NAN, |
| 1071 | }; |
| 1072 | let nv = n.value(); |
| 1073 | if nv.is_nan() || sv.is_nan() { |
| 1074 | false |
| 1075 | } else { |
| 1076 | nv == sv |
| 1077 | } |
| 1078 | } |
| 1079 | (PrimitiveValue::Boolean(b), other) => { |
| 1080 | let num = if *b { 1.0 } else { 0.0 }; |
| 1081 | js_abstract_equal(&PrimitiveValue::Number(FloatValue::new(num)), other) |
| 1082 | } |
| 1083 | (other, PrimitiveValue::Boolean(b)) => { |
| 1084 | let num = if *b { 1.0 } else { 0.0 }; |
| 1085 | js_abstract_equal(other, &PrimitiveValue::Number(FloatValue::new(num))) |
| 1086 | } |
| 1087 | // null/undefined vs number/string => false |
| 1088 | _ => false, |
| 1089 | } |
| 1090 | } |
| 1091 | |
| 1092 | // ============================================================================= |
| 1093 | // JavaScript Number.toString() approximation |
| 1094 | // ============================================================================= |
| 1095 | |
| 1096 | /// ECMAScript ToInt32: convert f64 to i32 with modular (wrapping) semantics. |
| 1097 | fn js_to_int32(n: f64) -> i32 { |
| 1098 | if n.is_nan() || n.is_infinite() || n == 0.0 { |
| 1099 | return 0; |
| 1100 | } |
| 1101 | // Truncate, then wrap to 32 bits |
| 1102 | let int64 = (n.trunc() as i64) & 0xFFFFFFFF; |
| 1103 | // Reinterpret as signed i32 |
| 1104 | if int64 >= 0x80000000 { |
| 1105 | (int64 as u32) as i32 |
| 1106 | } else { |
| 1107 | int64 as i32 |
| 1108 | } |
| 1109 | } |
| 1110 | |
| 1111 | /// ECMAScript ToUint32: convert f64 to u32 with modular (wrapping) semantics. |
| 1112 | fn js_to_uint32(n: f64) -> u32 { |
| 1113 | js_to_int32(n) as u32 |
| 1114 | } |