{"parents":["a40ade1e6148b2a13e1179c477033324ea90debd"],"patch":"diff --git a\/compiler\/forget\/src\/CompilerFlags.ts b\/compiler\/forget\/src\/CompilerFlags.ts\nindex 30d6be8756..abd58ef284 100644\n--- a\/compiler\/forget\/src\/CompilerFlags.ts\n+++ b\/compiler\/forget\/src\/CompilerFlags.ts\n@@ -5,10 +5,6 @@\n * LICENSE file in the root directory of this source tree.\n *\/\n \n-type Flags = {\n- enableNewReactiveFunctionBuilder: boolean;\n-};\n+type Flags = {};\n \n-export const flags: Flags = {\n- enableNewReactiveFunctionBuilder: false,\n-};\n+export const flags: Flags = {};\ndiff --git a\/compiler\/forget\/src\/CompilerPipeline.ts b\/compiler\/forget\/src\/CompilerPipeline.ts\nindex a77c71e9ce..44cfc54bd5 100644\n--- a\/compiler\/forget\/src\/CompilerPipeline.ts\n+++ b\/compiler\/forget\/src\/CompilerPipeline.ts\n@@ -6,7 +6,6 @@\n *\/\n import { NodePath } from \"@babel\/traverse\";\n import * as t from \"@babel\/types\";\n-import { flags } from \".\/CompilerFlags\";\n import {\n Environment,\n HIRFunction,\n@@ -20,10 +19,8 @@ import {\n alignReactiveScopesToBlockScopes,\n buildReactiveBlocks,\n buildReactiveFunction,\n- buildReactiveFunctionWithoutScopes,\n codegenReactiveFunction,\n flattenReactiveLoops,\n- inferReactiveScopes,\n inferReactiveScopeVariables,\n mergeOverlappingReactiveScopes,\n propagateScopeDependencies,\n@@ -77,46 +74,33 @@ export function* run(\n inferReactiveScopeVariables(hir);\n yield log({ kind: \"hir\", name: \"InferReactiveScopeVariables\", value: hir });\n \n- let reactiveFunction: ReactiveFunction;\n- if (!flags.enableNewReactiveFunctionBuilder) {\n- inferReactiveScopes(hir);\n- yield log({ kind: \"hir\", name: \"InferReactiveScopes\", value: hir });\n-\n- reactiveFunction = buildReactiveFunction(hir);\n- yield log({\n- kind: \"reactive\",\n- name: \"BuildReactiveFunction\",\n- value: reactiveFunction,\n- });\n- } else {\n- reactiveFunction = buildReactiveFunctionWithoutScopes(hir);\n- yield log({\n- kind: \"reactive\",\n- name: \"BuildReactiveFunction\",\n- value: reactiveFunction,\n- });\n-\n- alignReactiveScopesToBlockScopes(reactiveFunction);\n- yield log({\n- kind: \"reactive\",\n- name: \"AlignReactiveScopesToBlockScopes\",\n- value: reactiveFunction,\n- });\n-\n- mergeOverlappingReactiveScopes(reactiveFunction);\n- yield log({\n- kind: \"reactive\",\n- name: \"MergeOverlappingReactiveScopes\",\n- value: reactiveFunction,\n- });\n-\n- buildReactiveBlocks(reactiveFunction);\n- yield log({\n- kind: \"reactive\",\n- name: \"BuildReactiveBlocks\",\n- value: reactiveFunction,\n- });\n- }\n+ const reactiveFunction = buildReactiveFunction(hir);\n+ yield log({\n+ kind: \"reactive\",\n+ name: \"BuildReactiveFunction\",\n+ value: reactiveFunction,\n+ });\n+\n+ alignReactiveScopesToBlockScopes(reactiveFunction);\n+ yield log({\n+ kind: \"reactive\",\n+ name: \"AlignReactiveScopesToBlockScopes\",\n+ value: reactiveFunction,\n+ });\n+\n+ mergeOverlappingReactiveScopes(reactiveFunction);\n+ yield log({\n+ kind: \"reactive\",\n+ name: \"MergeOverlappingReactiveScopes\",\n+ value: reactiveFunction,\n+ });\n+\n+ buildReactiveBlocks(reactiveFunction);\n+ yield log({\n+ kind: \"reactive\",\n+ name: \"BuildReactiveBlocks\",\n+ value: reactiveFunction,\n+ });\n \n pruneUnusedLabels(reactiveFunction);\n yield log({\ndiff --git a\/compiler\/forget\/src\/HIR\/ReactiveFunctionVisitor.ts b\/compiler\/forget\/src\/HIR\/ReactiveFunctionVisitor.ts\ndeleted file mode 100644\nindex 579c462a03..0000000000\n--- a\/compiler\/forget\/src\/HIR\/ReactiveFunctionVisitor.ts\n+++ \/dev\/null\n@@ -1,958 +0,0 @@\n-\/**\n- * Copyright (c) Facebook, Inc. and its affiliates.\n- *\n- * This source code is licensed under the MIT license found in the\n- * LICENSE file in the root directory of this source tree.\n- *\/\n-\n-import invariant from \"invariant\";\n-import todo from \"..\/Utils\/todo\";\n-import { assertExhaustive } from \"..\/Utils\/utils\";\n-import {\n- BasicBlock,\n- BlockId,\n- GotoVariant,\n- HIR,\n- HIRFunction,\n- Instruction,\n- InstructionId,\n- InstructionValue,\n- Place,\n- SourceLocation,\n-} from \".\/HIR\";\n-\n-\/**\n- * Function to visit HIR as a tree of high-level constructs rather than as a sequence\n- * of lower-level basic blocks. Intended for use in codegen and reactive scope\n- * construction which need to see the original \"shape\" of the code.\n- *\n- * See the {@link Visitor} interface for more about implementing a visitor.\n- *\/\n-export function visitTreeForReactiveFunction<\n- TBlockBuilder,\n- TBlock,\n- TInit,\n- TValueBlock,\n- TValue,\n- TStatement,\n- TCase\n->(\n- fn: HIRFunction,\n- visitor: Visitor<\n- TBlockBuilder,\n- TBlock,\n- TInit,\n- TValueBlock,\n- TValue,\n- TStatement,\n- TCase\n- >\n-): TBlock {\n- const cx = new Context(fn.body);\n- const driver = new Driver(cx, visitor);\n- return driver.traverseBlock(cx.block(fn.body.entry));\n-}\n-\n-class Driver<\n- TBlockBuilder,\n- TBlock,\n- TInit,\n- TValueBlock,\n- TValue,\n- TStatement,\n- TCase\n-> {\n- cx: Context;\n- visitor: Visitor<\n- TBlockBuilder,\n- TBlock,\n- TInit,\n- TValueBlock,\n- TValue,\n- TStatement,\n- TCase\n- >;\n-\n- constructor(\n- cx: Context,\n- visitor: Visitor<\n- TBlockBuilder,\n- TBlock,\n- TInit,\n- TValueBlock,\n- TValue,\n- TStatement,\n- TCase\n- >\n- ) {\n- this.cx = cx;\n- this.visitor = visitor;\n- }\n-\n- traverseBlock(block: BasicBlock): TBlock {\n- const blockValue = this.visitor.enterBlock();\n- this.visitBlock(block, blockValue);\n- return this.visitor.leaveBlock(blockValue);\n- }\n-\n- visitBlock(block: BasicBlock, blockValue: TBlockBuilder): void {\n- invariant(\n- !this.cx.emitted.has(block.id),\n- `Cannot emit the same block twice: bb${block.id}`\n- );\n- this.cx.emitted.add(block.id);\n- for (const instr of block.instructions) {\n- this.visitInstr(instr, blockValue);\n- }\n-\n- const terminal = block.terminal;\n- const scheduleIds = [];\n- switch (terminal.kind) {\n- case \"return\": {\n- const value =\n- terminal.value != null\n- ? this.visitPlace(terminal.value, terminal.id)\n- : null;\n- this.visitor.visitTerminalId(terminal.id);\n- this.visitor.appendBlock(\n- blockValue,\n- this.visitor.visitTerminal({\n- kind: \"return\",\n- loc: terminal.loc,\n- value,\n- id: terminal.id,\n- })\n- );\n- break;\n- }\n- case \"throw\": {\n- const value = this.visitPlace(terminal.value, terminal.id);\n- this.visitor.visitTerminalId(terminal.id);\n- this.visitor.appendBlock(\n- blockValue,\n- this.visitor.visitTerminal({\n- kind: \"throw\",\n- value,\n- id: terminal.id,\n- })\n- );\n- break;\n- }\n- case \"if\": {\n- const test = this.visitPlace(terminal.test, terminal.id);\n- const fallthroughId =\n- terminal.fallthrough !== null &&\n- !this.cx.isScheduled(terminal.fallthrough)\n- ? terminal.fallthrough\n- : null;\n- const alternateId =\n- terminal.alternate !== terminal.fallthrough\n- ? terminal.alternate\n- : null;\n-\n- if (fallthroughId !== null) {\n- const scheduleId = this.cx.schedule(fallthroughId, \"if\");\n- scheduleIds.push(scheduleId);\n- }\n-\n- this.visitor.visitTerminalId(terminal.id);\n- let consequent: TBlock | null = null;\n- if (this.cx.isScheduled(terminal.consequent)) {\n- const break_ = this.visitBreak(terminal.consequent, null);\n- if (break_ !== null) {\n- const builder = this.visitor.enterBlock();\n- this.visitor.appendBlock(builder, break_);\n- consequent = this.visitor.leaveBlock(builder);\n- }\n- } else {\n- consequent = this.traverseBlock(\n- this.cx.ir.blocks.get(terminal.consequent)!\n- );\n- }\n-\n- let alternate: TBlock | null = null;\n- if (alternateId !== null) {\n- if (this.cx.isScheduled(alternateId)) {\n- const break_ = this.visitBreak(alternateId, null);\n- if (break_ !== null) {\n- const builder = this.visitor.enterBlock();\n- this.visitor.appendBlock(builder, break_);\n- alternate = this.visitor.leaveBlock(builder);\n- }\n- } else {\n- alternate = this.traverseBlock(this.cx.ir.blocks.get(alternateId)!);\n- }\n- }\n-\n- this.cx.unscheduleAll(scheduleIds);\n- if (fallthroughId !== null) {\n- this.visitor.appendBlock(\n- blockValue,\n- this.visitor.visitTerminal({\n- kind: \"if\",\n- test,\n- consequent: consequent ?? this.emptyBlock(),\n- alternate: alternate,\n- id: terminal.id,\n- }),\n- fallthroughId\n- );\n- this.visitBlock(this.cx.ir.blocks.get(fallthroughId)!, blockValue);\n- } else {\n- this.visitor.appendBlock(\n- blockValue,\n- this.visitor.visitTerminal({\n- kind: \"if\",\n- test,\n- consequent: consequent ?? this.emptyBlock(),\n- alternate: alternate,\n- id: terminal.id,\n- })\n- );\n- }\n- break;\n- }\n- case \"switch\": {\n- const test = this.visitPlace(terminal.test, terminal.id);\n- const fallthroughId =\n- terminal.fallthrough !== null &&\n- !this.cx.isScheduled(terminal.fallthrough)\n- ? terminal.fallthrough\n- : null;\n- if (fallthroughId !== null) {\n- const scheduleId = this.cx.schedule(fallthroughId, \"switch\");\n- scheduleIds.push(scheduleId);\n- }\n-\n- this.visitor.visitTerminalId(terminal.id);\n- const cases: Array = [];\n- [...terminal.cases].reverse().forEach((case_, index) => {\n- const test =\n- case_.test !== null\n- ? this.visitPlace(case_.test, terminal.id)\n- : null;\n-\n- let consequent;\n- if (this.cx.isScheduled(case_.block)) {\n- \/\/ cases which are empty or contain only a `break` may point to blocks\n- \/\/ that are already scheduled. emit as follows:\n- \/\/ - if the block is for another case branch, don't emit a break and fall-through\n- \/\/ - else, emit an explicit break.\n- const break_ = this.visitBreak(case_.block, null);\n- if (\n- index === 0 &&\n- break_ === null &&\n- case_.block === terminal.fallthrough &&\n- case_.test === null\n- ) {\n- \/\/ If the last case statement (first in reverse order) is a default that\n- \/\/ jumps to the fallthrough, then we would emit a useless `default: {}`,\n- \/\/ so instead skip this case.\n- return;\n- }\n- const block = this.visitor.enterBlock();\n- if (break_ !== null) {\n- this.visitor.appendBlock(block, break_);\n- }\n- consequent = this.visitor.leaveBlock(block);\n- } else {\n- consequent = this.traverseBlock(\n- this.cx.ir.blocks.get(case_.block)!\n- );\n- const scheduleId = this.cx.schedule(case_.block, \"case\");\n- scheduleIds.push(scheduleId);\n- }\n- cases.push(this.visitor.visitCase(test, consequent));\n- });\n- cases.reverse();\n-\n- this.cx.unscheduleAll(scheduleIds);\n- if (fallthroughId !== null) {\n- this.visitor.appendBlock(\n- blockValue,\n- this.visitor.visitTerminal({\n- kind: \"switch\",\n- test,\n- cases,\n- id: terminal.id,\n- }),\n- fallthroughId\n- );\n- this.visitBlock(this.cx.ir.blocks.get(fallthroughId)!, blockValue);\n- } else {\n- this.visitor.appendBlock(\n- blockValue,\n- this.visitor.visitTerminal({\n- kind: \"switch\",\n- test,\n- cases,\n- id: terminal.id,\n- })\n- );\n- }\n- break;\n- }\n- case \"while\": {\n- const fallthroughId =\n- terminal.fallthrough !== null &&\n- !this.cx.isScheduled(terminal.fallthrough)\n- ? terminal.fallthrough\n- : null;\n- const loopId =\n- !this.cx.isScheduled(terminal.loop) &&\n- terminal.loop !== terminal.fallthrough\n- ? terminal.loop\n- : null;\n- const scheduleId = this.cx.scheduleLoop(\n- terminal.fallthrough,\n- terminal.test,\n- terminal.loop\n- );\n- scheduleIds.push(scheduleId);\n-\n- this.visitor.visitTerminalId(terminal.id);\n- const testBlock = this.cx.ir.blocks.get(terminal.test)!;\n- const testTerminal = testBlock.terminal;\n- invariant(\n- testTerminal.kind === \"if\",\n- \"Expected while loop test block to end in an if\"\n- );\n- const testValue = this.visitValueBlock(blockValue, testBlock, {\n- value: testTerminal.test,\n- id: testTerminal.id,\n- });\n- let loopBody: TBlock;\n- if (loopId) {\n- loopBody = this.traverseBlock(this.cx.ir.blocks.get(loopId)!);\n- } else {\n- const break_ = this.visitBreak(terminal.loop, null);\n- invariant(\n- break_ !== null,\n- \"If loop body is already scheduled it must be a break\"\n- );\n- const body = this.visitor.enterBlock();\n- this.visitor.appendBlock(body, break_);\n- loopBody = this.visitor.leaveBlock(body);\n- }\n-\n- this.cx.unscheduleAll(scheduleIds);\n- if (fallthroughId !== null) {\n- this.visitor.appendBlock(\n- blockValue,\n- this.visitor.visitTerminal({\n- kind: \"while\",\n- loc: terminal.loc,\n- test: testValue,\n- loop: loopBody,\n- id: terminal.id,\n- }),\n- fallthroughId\n- );\n- this.visitBlock(this.cx.ir.blocks.get(fallthroughId)!, blockValue);\n- } else {\n- this.visitor.appendBlock(\n- blockValue,\n- this.visitor.visitTerminal({\n- kind: \"while\",\n- loc: terminal.loc,\n- test: testValue,\n- loop: loopBody,\n- id: terminal.id,\n- })\n- );\n- }\n- break;\n- }\n- case \"for\": {\n- const loopId =\n- !this.cx.isScheduled(terminal.loop) &&\n- terminal.loop !== terminal.fallthrough\n- ? terminal.loop\n- : null;\n-\n- const fallthroughId =\n- terminal.fallthrough !== null &&\n- !this.cx.isScheduled(terminal.fallthrough)\n- ? terminal.fallthrough\n- : null;\n-\n- const scheduleId = this.cx.scheduleLoop(\n- terminal.fallthrough,\n- terminal.update,\n- terminal.loop\n- );\n- scheduleIds.push(scheduleId);\n-\n- this.visitor.visitTerminalId(terminal.id);\n-\n- const initBlock = this.cx.ir.blocks.get(terminal.init)!;\n- const initTerminal = initBlock.terminal;\n- invariant(\n- initTerminal.kind === \"goto\",\n- \"Expected for loop init block to end in a goto\"\n- );\n- const initValue = this.visitInitBlock(blockValue, initBlock);\n-\n- const testBlock = this.cx.ir.blocks.get(terminal.test)!;\n- const testTerminal = testBlock.terminal;\n- invariant(\n- testTerminal.kind === \"if\",\n- \"Expected for loop test block to end in an if\"\n- );\n- const testValue = this.visitValueBlock(blockValue, testBlock, {\n- value: testTerminal.test,\n- id: testTerminal.id,\n- });\n-\n- const updateBlock = this.cx.ir.blocks.get(terminal.update)!;\n- const updateTerminal = updateBlock.terminal;\n- invariant(\n- updateTerminal.kind === \"goto\",\n- \"Expected for loop update block to end in a goto\"\n- );\n- const updateValue = this.visitValueBlock(blockValue, updateBlock);\n-\n- let loopBody: TBlock;\n- if (loopId) {\n- loopBody = this.traverseBlock(this.cx.ir.blocks.get(loopId)!);\n- } else {\n- const break_ = this.visitBreak(terminal.loop, null);\n- invariant(\n- break_ !== null,\n- \"If loop body is already scheduled it must be a break\"\n- );\n- const body = this.visitor.enterBlock();\n- this.visitor.appendBlock(body, break_);\n- loopBody = this.visitor.leaveBlock(body);\n- }\n-\n- this.cx.unscheduleAll(scheduleIds);\n- if (fallthroughId !== null) {\n- this.visitor.appendBlock(\n- blockValue,\n- this.visitor.visitTerminal({\n- kind: \"for\",\n- init: initValue,\n- test: testValue,\n- update: updateValue,\n- loop: loopBody,\n- id: terminal.id,\n- }),\n- fallthroughId\n- );\n- this.visitBlock(this.cx.ir.blocks.get(fallthroughId)!, blockValue);\n- } else {\n- this.visitor.appendBlock(\n- blockValue,\n- this.visitor.visitTerminal({\n- kind: \"for\",\n- init: initValue,\n- test: testValue,\n- update: updateValue,\n- loop: loopBody,\n- id: terminal.id,\n- })\n- );\n- }\n- break;\n- }\n- case \"logical\": {\n- todo(\"Implement tree visitor for logical terminal\");\n- }\n- case \"goto\": {\n- this.visitor.visitTerminalId(terminal.id);\n- switch (terminal.variant) {\n- case GotoVariant.Break: {\n- const break_ = this.visitBreak(terminal.block, terminal.id);\n- if (break_ !== null) {\n- this.visitor.appendBlock(blockValue, break_);\n- }\n- break;\n- }\n- case GotoVariant.Continue: {\n- const continue_ = this.visitContinue(terminal.block, terminal.id);\n- if (continue_ !== null) {\n- this.visitor.appendBlock(blockValue, continue_);\n- }\n- break;\n- }\n- default: {\n- assertExhaustive(\n- terminal.variant,\n- `Unexpected goto variant '${terminal.variant}'`\n- );\n- }\n- }\n- break;\n- }\n- default: {\n- assertExhaustive(terminal, \"Unexpected terminal\");\n- }\n- }\n- }\n-\n- visitInitBlock(parent: TBlockBuilder, block: BasicBlock): TInit {\n- const initBlock = this.visitor.enterInitBlock(parent);\n- for (const instr of block.instructions) {\n- const value = this.visitor.visitValue(instr.value, instr.id);\n- const item = this.visitor.visitInstruction(instr, value);\n- this.visitor.appendInitBlock(initBlock, item);\n- }\n- return this.visitor.leaveInitBlock(initBlock);\n- }\n-\n- visitValueBlock(\n- parent: TBlockBuilder,\n- block: BasicBlock,\n- terminalValue?: { value: InstructionValue; id: InstructionId }\n- ): TValue {\n- const valueBlock = this.visitor.enterValueBlock(parent);\n- const instructions = [...block.instructions];\n- let lastValue: { value: InstructionValue; id: InstructionId } | null = null;\n- if (terminalValue != null) {\n- lastValue = terminalValue;\n- }\n- for (const instr of instructions) {\n- const value = this.visitor.visitValue(instr.value, instr.id);\n- const item = this.visitor.visitInstruction(instr, value);\n- this.visitor.appendValueBlock(valueBlock, item);\n- }\n- const value =\n- lastValue !== null\n- ? this.visitor.visitValue(lastValue.value, lastValue.id)\n- : null;\n- return this.visitor.leaveValueBlock(valueBlock, value);\n- }\n-\n- emptyBlock(): TBlock {\n- const block = this.visitor.enterBlock();\n- return this.visitor.leaveBlock(block);\n- }\n-\n- visitBreak(block: BlockId, id: InstructionId | null): TStatement | null {\n- const target = this.cx.getBreakTarget(block);\n- if (target === null) {\n- \/\/ TODO: we should always have a target\n- return null;\n- }\n- switch (target.type) {\n- case \"implicit\": {\n- return this.visitor.visitImplicitTerminal();\n- }\n- case \"unlabeled\": {\n- return this.visitor.visitTerminal({ kind: \"break\", label: null, id });\n- }\n- case \"labeled\": {\n- return this.visitor.visitTerminal({\n- kind: \"break\",\n- label: target.block,\n- id,\n- });\n- }\n- }\n- }\n-\n- visitContinue(block: BlockId, id: InstructionId): TStatement | null {\n- const target = this.cx.getContinueTarget(block);\n- invariant(\n- target !== null,\n- `Expected continue target to be scheduled for bb${block}`\n- );\n- switch (target.type) {\n- case \"labeled\": {\n- return this.visitor.visitTerminal({\n- kind: \"continue\",\n- label: target.block,\n- id,\n- });\n- }\n- case \"unlabeled\": {\n- return this.visitor.visitTerminal({\n- kind: \"continue\",\n- label: null,\n- id,\n- });\n- }\n- case \"implicit\": {\n- return this.visitor.visitImplicitTerminal();\n- }\n- default: {\n- assertExhaustive(\n- target.type,\n- `Unexpected continue target kind '${(target as any).type}'`\n- );\n- }\n- }\n- }\n-\n- visitInstr(instr: Instruction, blockValue: TBlockBuilder): void {\n- const value = this.visitor.visitValue(instr.value, instr.id);\n- const item = this.visitor.visitInstruction(instr, value);\n- this.visitor.appendBlock(blockValue, item);\n- }\n-\n- visitPlace(place: Place, id: InstructionId): TValue {\n- return this.visitor.visitValue(place, id);\n- }\n-}\n-\n-class Context {\n- ir: HIR;\n- #nextScheduleId: number = 0;\n-\n- \/**\n- * Used to track which blocks *have been* generated already in order to\n- * abort if a block is generated a second time. This is an error catching\n- * mechanism for debugging purposes, and is not used by the codegen algorithm\n- * to drive decisions about how to emit blocks.\n- *\/\n- emitted: Set = new Set();\n-\n- \/**\n- * A set of blocks that are already scheduled to be emitted by eg a parent.\n- * This allows child nodes to avoid re-emitting the same block and emit eg\n- * a break instead.\n- *\/\n- #scheduled: Set = new Set();\n-\n- \/**\n- * Represents which control flow operations are currently in scope, with the innermost\n- * scope last. Roughly speaking, the last ControlFlowTarget on the stack indicates where\n- * control will implicitly transfer, such that gotos to that block can be elided. Gotos\n- * targeting items higher up the stack may need labeled break or continue; see\n- * getBreakTarget() and getContinueTarget() for more details.\n- *\/\n- #controlFlowStack: Array = [];\n-\n- constructor(ir: HIR) {\n- this.ir = ir;\n- }\n-\n- block(id: BlockId): BasicBlock {\n- return this.ir.blocks.get(id)!;\n- }\n-\n- \/**\n- * Record that the given block will be emitted (eg by the codegen of a parent node)\n- * so that child nodes can avoid re-emitting it.\n- *\/\n- schedule(block: BlockId, type: \"if\" | \"switch\" | \"case\"): number {\n- const id = this.#nextScheduleId++;\n- invariant(\n- !this.#scheduled.has(block),\n- `Break block is already scheduled: bb${block}`\n- );\n- this.#scheduled.add(block);\n- this.#controlFlowStack.push({ block, id, type });\n- return id;\n- }\n-\n- scheduleLoop(\n- fallthroughBlock: BlockId,\n- continueBlock: BlockId,\n- loopBlock: BlockId | null\n- ): number {\n- const id = this.#nextScheduleId++;\n- const ownsBlock = !this.#scheduled.has(fallthroughBlock);\n- this.#scheduled.add(fallthroughBlock);\n- invariant(\n- !this.#scheduled.has(continueBlock),\n- `Continue block is already scheduled: bb${continueBlock}`\n- );\n- this.#scheduled.add(continueBlock);\n- let ownsLoop = false;\n- if (loopBlock !== null) {\n- ownsLoop = !this.#scheduled.has(loopBlock);\n- this.#scheduled.add(loopBlock);\n- }\n-\n- this.#controlFlowStack.push({\n- block: fallthroughBlock,\n- ownsBlock,\n- id,\n- type: \"loop\",\n- continueBlock,\n- loopBlock,\n- ownsLoop,\n- });\n- return id;\n- }\n-\n- \/**\n- * Removes a block that was scheduled; must be called after that block is emitted.\n- *\/\n- unschedule(scheduleId: number): void {\n- const last = this.#controlFlowStack.pop();\n- invariant(\n- last !== undefined && last.id === scheduleId,\n- \"Can only unschedule the last target\"\n- );\n- if (last.type !== \"loop\" || last.ownsBlock !== null) {\n- this.#scheduled.delete(last.block);\n- }\n- if (last.type === \"loop\") {\n- this.#scheduled.delete(last.continueBlock);\n- if (last.ownsLoop && last.loopBlock !== null) {\n- this.#scheduled.delete(last.loopBlock);\n- }\n- }\n- }\n-\n- \/**\n- * Helper to unschedule multiple scheduled blocks. The ids should be in\n- * the order in which they were scheduled, ie most recently scheduled last.\n- *\/\n- unscheduleAll(scheduleIds: Array): void {\n- for (let i = scheduleIds.length - 1; i >= 0; i--) {\n- this.unschedule(scheduleIds[i]!);\n- }\n- }\n-\n- \/**\n- * Check if the given @param block is scheduled or not.\n- *\/\n- isScheduled(block: BlockId): boolean {\n- return this.#scheduled.has(block);\n- }\n-\n- \/**\n- * Given the current control flow stack, determines how a `break` to the given @param block\n- * must be emitted. Returns as follows:\n- * - 'implicit' if control would implicitly transfer to that block\n- * - 'labeled' if a labeled break is required to transfer control to that block\n- * - 'unlabeled' if an unlabeled break would transfer to that block\n- * - null if there is no information for this block\n- *\n- * The returned 'block' value should be used as the label if necessary.\n- *\/\n- getBreakTarget(\n- block: BlockId\n- ): { block: BlockId; type: ControlFlowKind } | null {\n- let hasPrecedingLoop = false;\n- for (let i = this.#controlFlowStack.length - 1; i >= 0; i--) {\n- const target = this.#controlFlowStack[i]!;\n- if (target.block === block) {\n- let type: ControlFlowKind;\n- if (target.type === \"loop\") {\n- \/\/ breaking out of a loop requires an explicit break,\n- \/\/ but only requires a label if breaking past the innermost loop.\n- type = hasPrecedingLoop ? \"labeled\" : \"unlabeled\";\n- } else if (i === this.#controlFlowStack.length - 1) {\n- \/\/ breaking to the last break point, which is where control will transfer\n- \/\/ implicitly\n- type = \"implicit\";\n- } else {\n- \/\/ breaking somewhere else requires an explicit break\n- type = \"labeled\";\n- }\n- return {\n- block: target.block,\n- type,\n- };\n- }\n- hasPrecedingLoop ||= target.type === \"loop\";\n- }\n- return null;\n- }\n-\n- \/**\n- * Given the current control flow stack, determines how a `continue` to the given @param block\n- * must be emitted. Returns as follows:\n- * - 'implicit' if control would implicitly continue to that block\n- * - 'labeled' if a labeled continue is required to continue to that block\n- * - 'unlabeled' if an unlabeled continue would transfer to that block\n- * - null if there is no information for this block\n- *\n- * The returned 'block' value should be used as the label if necessary.\n- *\/\n- getContinueTarget(\n- block: BlockId\n- ): { block: BlockId; type: ControlFlowKind } | null {\n- let hasPrecedingLoop = false;\n- for (let i = this.#controlFlowStack.length - 1; i >= 0; i--) {\n- const target = this.#controlFlowStack[i]!;\n- if (target.type == \"loop\" && target.continueBlock === block) {\n- let type: ControlFlowKind;\n- if (hasPrecedingLoop) {\n- \/\/ continuing to a loop that is not the innermost loop always requires\n- \/\/ a label\n- type = \"labeled\";\n- } else if (i === this.#controlFlowStack.length - 1) {\n- \/\/ continuing to the last break point, which is where control will\n- \/\/ transfer to naturally\n- type = \"implicit\";\n- } else {\n- \/\/ the continue is inside some conditional logic, requires an explicit\n- \/\/ continue\n- type = \"unlabeled\";\n- }\n- return {\n- block: target.block,\n- type,\n- };\n- }\n- hasPrecedingLoop ||= target.type === \"loop\";\n- }\n- return null;\n- }\n-\n- debugBreakTargets(): Array {\n- return this.#controlFlowStack.map((target) => ({ ...target }));\n- }\n-}\n-\n-type ControlFlowKind = \"implicit\" | \"labeled\" | \"unlabeled\";\n-\n-type ControlFlowTarget =\n- | { type: \"if\"; block: BlockId; id: number }\n- | { type: \"switch\"; block: BlockId; id: number }\n- | { type: \"case\"; block: BlockId; id: number }\n- | {\n- type: \"loop\";\n- block: BlockId;\n- ownsBlock: boolean;\n- continueBlock: BlockId;\n- loopBlock: BlockId | null;\n- ownsLoop: boolean;\n- id: number;\n- };\n-\n-\/**\n- * An object that can receive structured callbacks to visit HIR as a tree,\n- * and convert it to an alternate format.\n- *\n- * TBlock = representation of a list of statements\n- * TValue = represenation of an InstructionValue\n- * TStatement = representation of an Instruction\n- * TCase = representation of a switch case\n- *\/\n-export interface Visitor<\n- TBlockBuilder,\n- TBlock,\n- TInit,\n- TValueBlock,\n- TValue,\n- TStatement,\n- TCase\n-> {\n- \/**\n- * Must create an \"empty\" instance of the visitor's represenation for\n- * the contents of a block.\n- *\/\n- enterBlock(): TBlockBuilder;\n-\n- \/**\n- * Appends an item onto the given block, with an optional label. The label\n- * indicates that a break\/continue will proceed to code *after* the given item.\n- *\/\n- appendBlock(block: TBlockBuilder, item: TStatement, label?: BlockId): void;\n-\n- \/**\n- * Converts the visitor's block representation into the representation of a\n- * block item, simultaneously \"closing\" the given block. The block will no\n- * longer be modified by the visitor driver.\n- *\/\n- leaveBlock(block: TBlockBuilder): TBlock;\n-\n- \/**\n- * Must create an \"empty\" instance of the visitor's representation for a value\n- * block, which can generally contain only expressions but not statements. The\n- * currently active parent block is passed as an argument.\n- *\n- * The exception is the for initializer, which may contain declarations but not\n- * other statement types.\n- *\/\n- enterValueBlock(block: TBlockBuilder): TValueBlock;\n-\n- \/**\n- * Appends an item onto the given value block.\n- *\/\n- appendValueBlock(block: TValueBlock, item: TStatement): void;\n-\n- \/**\n- * Converts the visitor's value block (and final value) to the visitor's\n- * value representation.\n- *\/\n- leaveValueBlock(block: TValueBlock, value: TValue | null): TValue;\n-\n- enterInitBlock(block: TBlockBuilder): TValueBlock;\n-\n- appendInitBlock(block: TValueBlock, item: TStatement): void;\n-\n- leaveInitBlock(block: TValueBlock): TInit;\n-\n- \/**\n- * Convert an InstructionValue into the visitor's own representation\n- * of a value.\n- *\/\n- visitValue(value: InstructionValue, id: InstructionId): TValue;\n-\n- \/**\n- * Convert an Instruction into the visitor's own representation of\n- * a block item.\n- *\/\n- visitInstruction(instruction: Instruction, value: TValue): TStatement;\n-\n- \/**\n- * Called when a terminal is reached, before processing any of its\n- * possible branches.\n- *\/\n- visitTerminalId(id: InstructionId): void;\n-\n- \/**\n- * Converts a break\/continue that is implicit — that does not strictly\n- * have to be emitted — to the visitor's representation. The visitor\n- * can choose to return null if this does not need to be represented.\n- *\/\n- visitImplicitTerminal(): TStatement | null;\n-\n- \/**\n- * Converts a terminal into the visitor's own representation of a block\n- * item. Note that the terminal differs from HIR Terminals, because\n- * values and block ids will have already been converted into the visitor's\n- * own representations.\n- *\/\n- visitTerminal(\n- terminal: BlockTerminal\n- ): TStatement;\n-\n- \/**\n- * Visits a switch case statement, which is collected into a switch terminal\n- * variant.\n- *\/\n- visitCase(test: TValue | null, block: TBlock): TCase;\n-}\n-\n-export type BlockTerminal =\n- | {\n- kind: \"return\";\n- loc: SourceLocation;\n- value: TValue | null;\n- id: InstructionId;\n- }\n- | { kind: \"throw\"; value: TValue; id: InstructionId }\n- | {\n- kind: \"if\";\n- test: TValue;\n- consequent: TBlock;\n- alternate: TBlock | null;\n- id: InstructionId;\n- }\n- | { kind: \"switch\"; test: TValue; cases: Array; id: InstructionId }\n- | {\n- kind: \"while\";\n- loc: SourceLocation;\n- test: TValue;\n- loop: TBlock;\n- id: InstructionId;\n- }\n- | {\n- kind: \"for\";\n- init: TInit;\n- test: TValue;\n- update: TValue;\n- loop: TBlock;\n- id: InstructionId;\n- }\n- | { kind: \"break\"; label: BlockId | null; id: InstructionId | null }\n- | { kind: \"continue\"; label: BlockId | null; id: InstructionId };\ndiff --git a\/compiler\/forget\/src\/ReactiveScopes\/BuildReactiveFunction.ts b\/compiler\/forget\/src\/ReactiveScopes\/BuildReactiveFunction.ts\nindex 5b39e05dd1..de081db311 100644\n--- a\/compiler\/forget\/src\/ReactiveScopes\/BuildReactiveFunction.ts\n+++ b\/compiler\/forget\/src\/ReactiveScopes\/BuildReactiveFunction.ts\n@@ -15,15 +15,11 @@ import {\n Place,\n ReactiveBlock,\n ReactiveFunction,\n- ReactiveScope,\n- ReactiveScopeBlock,\n ReactiveStatement,\n ReactiveTerminal,\n ReactiveValueBlock,\n- ScopeId,\n } from \"..\/HIR\/HIR\";\n import { BlockTerminal, Visitor, visitTree } from \"..\/HIR\/HIRTreeVisitor\";\n-import { eachInstructionOperand } from \"..\/HIR\/visitors\";\n import { assertExhaustive } from \"..\/Utils\/utils\";\n \n export function buildReactiveFunction(fn: HIRFunction): ReactiveFunction {\n@@ -40,22 +36,8 @@ export function buildReactiveFunction(fn: HIRFunction): ReactiveFunction {\n };\n }\n \n-type BlockKind =\n- | { kind: \"block\"; block: ReactiveBlock }\n- | { kind: \"scope\"; block: ReactiveBlock; scope: ReactiveScope };\n-\n class Builder {\n- #instructions: ReactiveBlock;\n- #stack: Array<\n- | { kind: \"scope\"; block: ReactiveScopeBlock }\n- | { kind: \"block\"; block: ReactiveBlock }\n- >;\n-\n- constructor() {\n- const block: ReactiveBlock = [];\n- this.#instructions = block;\n- this.#stack = [{ kind: \"block\", block }];\n- }\n+ #instructions: ReactiveBlock = [];\n \n append(item: ReactiveStatement, label: BlockId | undefined): void {\n if (label !== undefined) {\n@@ -65,45 +47,8 @@ class Builder {\n this.#instructions.push(item);\n }\n \n- startScope(scope: ReactiveScope): void {\n- const block: ReactiveScopeBlock = {\n- kind: \"scope\",\n- scope,\n- instructions: [],\n- };\n- this.append(block, undefined);\n- this.#instructions = block.instructions;\n- this.#stack.push({ kind: \"scope\", block });\n- }\n-\n- visitId(id: InstructionId): void {\n- for (let i = 0; i < this.#stack.length; i++) {\n- const entry = this.#stack[i]!;\n- if (entry.kind === \"scope\" && id >= entry.block.scope.range.end) {\n- this.#stack.length = i;\n- break;\n- }\n- }\n- const last = this.#stack[this.#stack.length - 1]!;\n- if (last.kind === \"block\") {\n- this.#instructions = last.block;\n- } else {\n- this.#instructions = last.block.instructions;\n- }\n- }\n-\n complete(): ReactiveBlock {\n- \/\/ TODO @josephsavona: debug two failures of this\n- \/\/ invariant(\n- \/\/ this.#stack.length === 1,\n- \/\/ \"Expected all scopes to be closed when exiting a block\"\n- \/\/ );\n- const first = this.#stack[0]!;\n- invariant(\n- first.kind === \"block\",\n- \"Expected first stack item to be a basic block\"\n- );\n- return first.block;\n+ return this.#instructions;\n }\n }\n \n@@ -119,18 +64,8 @@ class ReactiveFunctionBuilder\n { test: InstructionValue | null; block: ReactiveBlock }\n >\n {\n- #builders: Array = [];\n- #scopes: Set = new Set();\n-\n- visitId(id: InstructionId): void {\n- const builder = this.#builders[this.#builders.length - 1]!;\n- builder.visitId(id);\n- }\n-\n enterBlock(): Builder {\n- const builder = new Builder();\n- this.#builders.push(builder);\n- return builder;\n+ return new Builder();\n }\n appendBlock(\n block: Builder,\n@@ -140,11 +75,6 @@ class ReactiveFunctionBuilder\n block.append(item, label);\n }\n leaveBlock(block: Builder): ReactiveBlock {\n- const builder = this.#builders.pop();\n- invariant(\n- builder === block,\n- \"Expected enterBlock\/leaveBlock to be called 1:1\"\n- );\n return block.complete();\n }\n \n@@ -196,18 +126,9 @@ class ReactiveFunctionBuilder\n instruction: Instruction,\n value: InstructionValue | ReactiveValueBlock\n ): ReactiveStatement {\n- this.visitId(instruction.id);\n- const scope = getInstructionScope(instruction);\n- if (scope !== null && !this.#scopes.has(scope.id)) {\n- this.#scopes.add(scope.id);\n- const builder = this.#builders[this.#builders.length - 1]!;\n- builder.startScope(scope);\n- }\n return { kind: \"instruction\", instruction };\n }\n- visitTerminalId(id: InstructionId): void {\n- this.visitId(id);\n- }\n+ visitTerminalId(id: InstructionId): void {}\n visitImplicitTerminal(): ReactiveStatement | null {\n return null;\n }\n@@ -311,26 +232,3 @@ class ReactiveFunctionBuilder\n return { test, block };\n }\n }\n-\n-function getInstructionScope(instr: Instruction): ReactiveScope | null {\n- if (\n- instr.lvalue.place.identifier.scope !== null &&\n- isScopeActive(instr.lvalue.place.identifier.scope, instr.id)\n- ) {\n- return instr.lvalue.place.identifier.scope;\n- } else {\n- for (const operand of eachInstructionOperand(instr)) {\n- if (\n- operand.identifier.scope !== null &&\n- isScopeActive(operand.identifier.scope, instr.id)\n- ) {\n- return operand.identifier.scope;\n- }\n- }\n- }\n- return null;\n-}\n-\n-function isScopeActive(scope: ReactiveScope, id: InstructionId): boolean {\n- return id >= scope.range.start && id < scope.range.end;\n-}\ndiff --git a\/compiler\/forget\/src\/ReactiveScopes\/BuildReactiveFunctionWithoutScopes.ts b\/compiler\/forget\/src\/ReactiveScopes\/BuildReactiveFunctionWithoutScopes.ts\ndeleted file mode 100644\nindex de081db311..0000000000\n--- a\/compiler\/forget\/src\/ReactiveScopes\/BuildReactiveFunctionWithoutScopes.ts\n+++ \/dev\/null\n@@ -1,234 +0,0 @@\n-\/**\n- * Copyright (c) Facebook, Inc. and its affiliates.\n- *\n- * This source code is licensed under the MIT license found in the\n- * LICENSE file in the root directory of this source tree.\n- *\/\n-\n-import invariant from \"invariant\";\n-import {\n- BlockId,\n- HIRFunction,\n- Instruction,\n- InstructionId,\n- InstructionValue,\n- Place,\n- ReactiveBlock,\n- ReactiveFunction,\n- ReactiveStatement,\n- ReactiveTerminal,\n- ReactiveValueBlock,\n-} from \"..\/HIR\/HIR\";\n-import { BlockTerminal, Visitor, visitTree } from \"..\/HIR\/HIRTreeVisitor\";\n-import { assertExhaustive } from \"..\/Utils\/utils\";\n-\n-export function buildReactiveFunction(fn: HIRFunction): ReactiveFunction {\n- const builder = new ReactiveFunctionBuilder();\n- const body = visitTree(fn, builder);\n- invariant(body != null, \"Expected a root block\");\n- return {\n- loc: fn.loc,\n- id: fn.id,\n- params: fn.params,\n- generator: fn.generator,\n- async: fn.async,\n- body,\n- };\n-}\n-\n-class Builder {\n- #instructions: ReactiveBlock = [];\n-\n- append(item: ReactiveStatement, label: BlockId | undefined): void {\n- if (label !== undefined) {\n- invariant(item.kind === \"terminal\", \"Only terminals may have a label\");\n- item.label = label;\n- }\n- this.#instructions.push(item);\n- }\n-\n- complete(): ReactiveBlock {\n- return this.#instructions;\n- }\n-}\n-\n-class ReactiveFunctionBuilder\n- implements\n- Visitor<\n- Builder,\n- ReactiveBlock,\n- ReactiveValueBlock,\n- ReactiveValueBlock,\n- InstructionValue | ReactiveValueBlock,\n- ReactiveStatement,\n- { test: InstructionValue | null; block: ReactiveBlock }\n- >\n-{\n- enterBlock(): Builder {\n- return new Builder();\n- }\n- appendBlock(\n- block: Builder,\n- item: ReactiveStatement,\n- label?: BlockId | undefined\n- ): void {\n- block.append(item, label);\n- }\n- leaveBlock(block: Builder): ReactiveBlock {\n- return block.complete();\n- }\n-\n- enterValueBlock(block: Builder): ReactiveValueBlock {\n- return {\n- kind: \"value-block\",\n- instructions: [],\n- last: null,\n- };\n- }\n- appendValueBlock(block: ReactiveValueBlock, item: ReactiveStatement): void {\n- block.instructions.push(item);\n- }\n- leaveValueBlock(\n- block: ReactiveValueBlock,\n- last: {\n- value: InstructionValue | ReactiveValueBlock;\n- id: InstructionId;\n- } | null\n- ): InstructionValue | ReactiveValueBlock {\n- if (last !== null) {\n- const { id, value } = last;\n- invariant(\n- value.kind !== \"value-block\",\n- \"Expected value block to end in a value\"\n- );\n- block.last = { id, value };\n- }\n- return block;\n- }\n-\n- enterInitBlock(block: Builder): ReactiveValueBlock {\n- return this.enterValueBlock(block);\n- }\n- appendInitBlock(block: ReactiveValueBlock, item: ReactiveStatement): void {\n- this.appendValueBlock(block, item);\n- }\n- leaveInitBlock(block: ReactiveValueBlock): ReactiveValueBlock {\n- return block;\n- }\n-\n- visitValue(\n- value: InstructionValue,\n- id: InstructionId\n- ): InstructionValue | ReactiveValueBlock {\n- return value;\n- }\n- visitInstruction(\n- instruction: Instruction,\n- value: InstructionValue | ReactiveValueBlock\n- ): ReactiveStatement {\n- return { kind: \"instruction\", instruction };\n- }\n- visitTerminalId(id: InstructionId): void {}\n- visitImplicitTerminal(): ReactiveStatement | null {\n- return null;\n- }\n- visitTerminal(\n- terminal: BlockTerminal<\n- ReactiveValueBlock,\n- InstructionValue | ReactiveValueBlock,\n- ReactiveBlock,\n- { test: InstructionValue | null; block: ReactiveBlock }\n- >\n- ): ReactiveStatement {\n- let result: ReactiveTerminal;\n- switch (terminal.kind) {\n- case \"break\": {\n- result = { kind: \"break\", label: terminal.label, id: terminal.id };\n- break;\n- }\n- case \"continue\": {\n- result = { kind: \"continue\", label: terminal.label, id: terminal.id };\n- break;\n- }\n- case \"for\": {\n- const { test, update } = terminal;\n- result = {\n- kind: \"for\",\n- init: terminal.init,\n- test: terminal.test as ReactiveValueBlock,\n- update: terminal.update as ReactiveValueBlock,\n- loop: terminal.loop,\n- id: terminal.id,\n- };\n- break;\n- }\n- case \"if\": {\n- result = {\n- kind: \"if\",\n- test: terminal.test as Place,\n- consequent: terminal.consequent,\n- alternate: terminal.alternate,\n- id: terminal.id,\n- };\n- break;\n- }\n- case \"return\": {\n- const value = terminal.value;\n- if (value !== null && value.kind !== \"Identifier\") {\n- invariant(false, \"Expected return to be a Place\");\n- }\n- result = { kind: \"return\", value, id: terminal.id };\n- break;\n- }\n- case \"switch\": {\n- result = {\n- kind: \"switch\",\n- test: terminal.test as Place,\n- cases: terminal.cases as Array<{\n- test: Place | null;\n- block: ReactiveBlock | void;\n- }>,\n- id: terminal.id,\n- };\n- break;\n- }\n- case \"throw\": {\n- result = {\n- kind: \"throw\",\n- value: terminal.value as Place,\n- id: terminal.id,\n- };\n- break;\n- }\n- case \"while\": {\n- result = {\n- kind: \"while\",\n- test: terminal.test as ReactiveValueBlock,\n- loop: terminal.loop,\n- id: terminal.id,\n- };\n- break;\n- }\n- default: {\n- assertExhaustive(\n- terminal,\n- `Unexpected terminal kind '${(terminal as any).kind}'`\n- );\n- }\n- }\n- return {\n- kind: \"terminal\",\n- terminal: result,\n- label: null,\n- };\n- }\n- visitCase(\n- test: InstructionValue | ReactiveValueBlock | null,\n- block: ReactiveBlock\n- ): { test: InstructionValue | null; block: ReactiveBlock } {\n- if (test !== null && test.kind !== \"Identifier\") {\n- invariant(false, \"Expected a Place\");\n- }\n- return { test, block };\n- }\n-}\ndiff --git a\/compiler\/forget\/src\/ReactiveScopes\/InferReactiveScopes.ts b\/compiler\/forget\/src\/ReactiveScopes\/InferReactiveScopes.ts\ndeleted file mode 100644\nindex f2c47bd8a4..0000000000\n--- a\/compiler\/forget\/src\/ReactiveScopes\/InferReactiveScopes.ts\n+++ \/dev\/null\n@@ -1,470 +0,0 @@\n-\/**\n- * Copyright (c) Facebook, Inc. and its affiliates.\n- *\n- * This source code is licensed under the MIT license found in the\n- * LICENSE file in the root directory of this source tree.\n- *\/\n-\n-import invariant from \"invariant\";\n-import {\n- BlockId,\n- HIRFunction,\n- Instruction,\n- InstructionId,\n- InstructionValue,\n- makeInstructionId,\n- MutableRange,\n- ReactiveScope,\n- ScopeId,\n-} from \"..\/HIR\/HIR\";\n-import { BlockTerminal, Visitor, visitTree } from \"..\/HIR\/HIRTreeVisitor\";\n-import { printFunction } from \"..\/HIR\/PrintHIR\";\n-import {\n- eachInstructionOperand,\n- eachInstructionValueOperand,\n-} from \"..\/HIR\/visitors\";\n-import DisjointSet from \"..\/Utils\/DisjointSet\";\n-import { log } from \"..\/Utils\/logger\";\n-import { retainWhere } from \"..\/Utils\/utils\";\n-\n-\/**\n- * This is a second (final) stage of constructing reactive scopes. Prior to this pass,\n- * InferReactiveScopeVariables infers the sets of identifiers that \"construct together\",\n- * assigning each identifier in each scope the same ScopeId and same MutableRange which\n- * describes that span.\n- *\n- * Note that at this point reactive scopes describe ranges based on specific instructions\n- * at arbitrary points in the control flow graph. However, reactive scopes must align\n- * with control-flow boundaries — we can't memoize half of a loop!\n- *\n- * This pass refines the reactive scopes as follows:\n- *\n- * ## Expanding each reactive scope to align with control-flow boundaries (DONE)\n- *\n- * This corresponds with the shape of the AST: a scope that extends into an if consequent\n- * would expand across the alternate branch, A scope that extends partway into an if\n- * would expand to cover the full loop body, etc.\n- *\n- * ```javascript\n- * function foo(cond, a) {\n- * ⌵ original scope\n- * ⌵ expanded scope\n- * const x = []; ⌝ ⌝\n- * if (cond) { ⎮ ⎮\n- * ... ⎮ ⎮\n- * x.push(a); ⌟ ⎮\n- * ... ⎮\n- * } ⌟\n- * }\n- * ```\n- *\n- * ## Merging (some) overlapping reactive scopes (TODO)\n- *\n- * Two scopes overlap if there is one or more instruction that is inside the range\n- * of both scopes. In general, overlapping scopes are merged togther. The only\n- * exception to this is when one scope *shadows* another scope. For example:\n- *\n- * ```javascript\n- * function foo(cond, a) {\n- * ⌵ scope for x\n- * let x = []; ⌝\n- * if (cond) { ⎮\n- * ⌵ scope for y ⎮\n- * let y = []; ⌝ ⎮\n- * if (b) { ⎮ ⎮\n- * y.push(b); ⌟ ⎮\n- * } ⎮\n- * x.push(

{y}<\/div>); ⎮\n- * } ⌟\n- * }\n- * ```\n- *\n- * In this example the two scopes overlap, but mutation of the two scopes is not\n- * interleaved. Specifically within the y scope there are no instructions that\n- * modify any other scope: the inner scope \"shadows\" the outer one. This category\n- * of overlap does *NOT* merge the scopes together.\n- *\n- * The implementation is inspired by the Rust notion of \"stacked borrows\". We traverse\n- * the control-flow graph in tree form, at each point keeping track of which scopes are\n- * active. So initially we see\n- *\n- * `let x = []`\n- * active scopes: [x]\n- *\n- * and mark the x scope as active.\n- *\n- * Then we later encounter\n- *\n- * `let y = [];`\n- * active scopes: [x, y]\n- *\n- * Here we first check to see if 'y' is already in the list of active scopes. It isn't,\n- * so we push it to the stop of the stack.\n- *\n- * Then\n- *\n- * `y.push(b)`\n- * active scopes: [x, y]\n- *\n- * Mutates y, so we check if y is the top of the stack. It is, so no merging must occur.\n- *\n- * If instead we saw eg\n- *\n- * `x.push(b)`\n- * active scopes: [x, y]\n- *\n- * Then we would see that 'x' is active, but that it is shadowed. The two scopes would have\n- * to be merged.\n- *\/\n-export function inferReactiveScopes(fn: HIRFunction) {\n- \/\/ Note sure if this is strictly required: in general the only way for two scopes to have\n- \/\/ the same range is if they were already inferred as aliasing together, and therefore\n- \/\/ they should end up with the same range and scope anyway.\n- mergeScopesWithIdenticalRanges(fn);\n-\n- visitTree(fn, new AlignReactiveScopesToBlockScopeRangeVisitor());\n- log(\n- () =>\n- `AlignReactiveScopesToBlockScopeRangeVisitor:\\n${printFunction(fn)}\\n\\n`\n- );\n- visitTree(fn, new MergeOverlappingReactiveScopesVisitor());\n-}\n-\n-\/**\n- * Finds scopes with identical ranges and merges them\n- *\/\n-function mergeScopesWithIdenticalRanges(fn: HIRFunction) {\n- const scopesByRange: Map = new Map();\n- for (const [_, block] of fn.body.blocks) {\n- for (const instr of block.instructions) {\n- const instrScope = getInstructionScope(instr);\n- if (instrScope === null) {\n- continue;\n- }\n- const rangeKey = `${instrScope.range.start}:${instrScope.range.end}`;\n- let scope = scopesByRange.get(rangeKey);\n- if (scope === undefined) {\n- scope = instrScope;\n- scopesByRange.set(rangeKey, scope);\n- }\n- if (scope.id !== instrScope.id) {\n- instrScope.id = scope.id;\n- instrScope.range = scope.range;\n- }\n- }\n- }\n-}\n-\n-class BlockScope {\n- seen: Set = new Set();\n- scopes: Array = [];\n-}\n-\n-type ShadowableReactiveScope = {\n- scope: ReactiveScope;\n- shadowedBy: ReactiveScope | null;\n-};\n-\n-class MergeOverlappingReactiveScopesVisitor\n- implements Visitor\n-{\n- scopes: Array = [];\n- seenScopes: Set = new Set();\n- joinedScopes: DisjointSet = new DisjointSet();\n-\n- \/**\n- * Determine if this scope is interleaved with any other scopes,\n- * and if so merge them.\n- *\/\n- visitScope(scope: ReactiveScope) {\n- const currentBlock = this.scopes[this.scopes.length - 1]!;\n- \/\/ Fast-path for the first time we see a new scope\n- if (!this.seenScopes.has(scope.id)) {\n- this.seenScopes.add(scope.id);\n- currentBlock.seen.add(scope.id);\n- currentBlock.scopes.push({ shadowedBy: null, scope });\n- return;\n- }\n- \/\/ Scope has already been seen, find it in the current block or a parent\n- let index = this.scopes.length - 1;\n- let nextBlock = currentBlock;\n- while (!nextBlock.seen.has(scope.id)) {\n- \/\/ scopes that cross control-flow boundaries are merged with overlapping\n- \/\/ scopes\n- this.joinedScopes.union([scope, ...nextBlock.scopes.map((s) => s.scope)]);\n- index--;\n- if (index < 0) {\n- \/\/ TODO: handle reassignments in multiple branches. these create new identifiers that\n- \/\/ add an entry to this.seenScopes but which are then removed when their blocks exit.\n- \/\/ this is also wrong for codegen, different versions of an identifier could be cached\n- \/\/ differently and so a reassigned version of a variable needs a separate declaration.\n- \/\/ console.log(`scope ${scope.id} not found`);\n-\n- \/\/ for (let i = this.scopes.length - 1; i > index; i--) {\n- \/\/ const s = this.scopes[i];\n- \/\/ console.log(\n- \/\/ JSON.stringify(\n- \/\/ {\n- \/\/ seen: Array.from(s.seen),\n- \/\/ scopes: s.scopes,\n- \/\/ },\n- \/\/ null,\n- \/\/ 2\n- \/\/ )\n- \/\/ );\n- \/\/ }\n- currentBlock.seen.add(scope.id);\n- currentBlock.scopes.push({ shadowedBy: null, scope });\n- return;\n- }\n- nextBlock = this.scopes[index]!;\n- }\n-\n- \/\/ Handle interleaving within a given block scope\n- let found = false;\n- for (let i = 0; i < nextBlock.scopes.length; i++) {\n- const current = nextBlock.scopes[i]!;\n- if (current.scope.id === scope.id) {\n- found = true;\n- if (current.shadowedBy !== null) {\n- this.joinedScopes.union([current.shadowedBy, current.scope]);\n- }\n- } else if (found && current.shadowedBy === null) {\n- \/\/ `scope` is shadowing `current`, but we don't know they are interleaved yet\n- current.shadowedBy = scope;\n- }\n- }\n- if (!currentBlock.seen.has(scope.id)) {\n- currentBlock.seen.add(scope.id);\n- currentBlock.scopes.push({ shadowedBy: null, scope });\n- }\n- }\n-\n- \/**\n- * Prune any scopes that are out of range\n- *\/\n- visitId(id: InstructionId) {\n- \/\/ console.log(`visitId: ${id}`);\n- const currentBlock = this.scopes[this.scopes.length - 1]!;\n- retainWhere(currentBlock.scopes, (pending) => {\n- if (pending.scope.range.end > id) {\n- return true;\n- } else {\n- currentBlock.seen.delete(pending.scope.id);\n- return false;\n- }\n- });\n- }\n-\n- enterBlock(): void {\n- this.scopes.push(new BlockScope());\n- }\n- enterValueBlock(): void {\n- this.enterBlock();\n- }\n- enterInitBlock(block: void): void {\n- this.enterBlock();\n- }\n- leaveInitBlock(block: void): void {\n- this.leaveBlock();\n- }\n- leaveValueBlock(\n- block: void,\n- value: { value: void; id: InstructionId } | null\n- ): void {\n- this.leaveBlock();\n- }\n- visitValue(value: InstructionValue, id: InstructionId): void {\n- this.visitId(id);\n- for (const operand of eachInstructionValueOperand(value)) {\n- if (\n- operand.identifier.scope !== null &&\n- id >= operand.identifier.scope.range.start &&\n- id < operand.identifier.scope.range.end\n- ) {\n- this.visitScope(operand.identifier.scope);\n- }\n- }\n- }\n- visitInstruction(instruction: Instruction, value: void): void {\n- this.visitId(instruction.id);\n- if (\n- instruction.lvalue.place.identifier.scope !== null &&\n- instruction.id >= instruction.lvalue.place.identifier.scope.range.start &&\n- instruction.id < instruction.lvalue.place.identifier.scope.range.end\n- ) {\n- this.visitScope(instruction.lvalue.place.identifier.scope);\n- }\n- }\n- visitTerminalId(id: InstructionId): void {\n- this.visitId(id);\n- }\n- visitImplicitTerminal(): void | null {}\n- visitTerminal(terminal: BlockTerminal): void {}\n- visitCase(test: void | null, block: void): void {}\n- appendBlock(block: void, item: void, label?: BlockId | undefined): void {}\n- appendValueBlock(block: void, item: void): void {}\n- appendInitBlock(block: void, item: void): void {}\n- leaveBlock(block: void): void {\n- this.scopes.pop();\n- if (this.scopes.length === 0) {\n- this.joinedScopes.forEach((scope, groupScope) => {\n- if (scope !== groupScope) {\n- groupScope.range.start = makeInstructionId(\n- Math.min(groupScope.range.start, scope.range.start)\n- );\n- groupScope.range.end = makeInstructionId(\n- Math.max(groupScope.range.end, scope.range.end)\n- );\n- scope.range = groupScope.range;\n- scope.id = groupScope.id;\n- }\n- });\n- }\n- }\n-}\n-\n-type PendingReactiveScope = { active: boolean; scope: ReactiveScope };\n-\n-\/**\n- * Aligns scopes to block scope boundaries.\n- *\n- * TODO @josephsavona this algorithm isn't quite right. we need to ensure that\n- * reactive scopes can only be closed (end updated) at the same block scope as they\n- * were opened (start encountered).\n- *\/\n-class AlignReactiveScopesToBlockScopeRangeVisitor\n- implements Visitor\n-{\n- \/\/ For each block scope (outer array) stores a list of ReactiveScopes that start\n- \/\/ in that block scope.\n- blockScopes: Array<{\n- kind: \"block\" | \"value\";\n- scopes: Array;\n- }> = [];\n-\n- \/\/ ReactiveScopes whose declaring block scope has ended but may still need to\n- \/\/ be \"closed\" (ie have their range.end be updated). A given scope can be in\n- \/\/ blockScopes OR this array but not both.\n- unclosedScopes: Array = [];\n-\n- \/\/ Set of all scope ids that have been seen so far, regardless of which of\n- \/\/ the above data structures they're in, to avoid tracking the same scope twice.\n- seenScopes: Set = new Set();\n-\n- visitId(id: InstructionId) {\n- const currentScopes = this.blockScopes[this.blockScopes.length - 1]!;\n- if (currentScopes.kind === \"value\") {\n- return;\n- }\n- const scopes = [...currentScopes.scopes, ...this.unclosedScopes];\n- for (const pending of scopes) {\n- if (!pending.active) {\n- continue;\n- }\n- if (id >= pending.scope.range.end) {\n- pending.active = false;\n- pending.scope.range.end = id;\n- }\n- }\n- }\n-\n- enterBlock(): void {\n- this.blockScopes.push({ kind: \"block\", scopes: [] });\n- }\n-\n- appendBlock(block: void, item: void, label?: BlockId | undefined): void {}\n-\n- leaveBlock(block: void): void {\n- const lastScope = this.blockScopes.pop();\n- invariant(\n- lastScope !== undefined && lastScope.kind === \"block\",\n- \"Expected enterBlock\/leaveBlock to be called 1:1\"\n- );\n- for (const scope of lastScope.scopes) {\n- if (scope.active) {\n- this.unclosedScopes.push(scope);\n- }\n- }\n- }\n-\n- enterValueBlock(): void {\n- this.blockScopes.push({ kind: \"value\", scopes: [] });\n- }\n- appendValueBlock(block: void, item: void): void {}\n- leaveValueBlock(\n- block: void,\n- value: { value: void; id: InstructionId } | null\n- ): void {\n- const lastScope = this.blockScopes.pop();\n- invariant(\n- lastScope !== undefined && lastScope.kind === \"value\",\n- \"Expected enterValueBlock\/leaveValueBlock to be called 1:1\"\n- );\n- for (const scope of lastScope.scopes) {\n- invariant(\n- scope.active,\n- \"Value scopes cannot be closed separately from the parent block\"\n- );\n- this.unclosedScopes.push(scope);\n- }\n- }\n-\n- enterInitBlock(block: void): void {\n- this.enterValueBlock();\n- }\n- appendInitBlock(block: void, item: void): void {}\n- leaveInitBlock(block: void): void {\n- this.leaveValueBlock(block, null);\n- }\n-\n- visitInstruction(instruction: Instruction, value: void): void {\n- this.visitId(instruction.id);\n- const scope = getInstructionScope(instruction);\n- if (scope !== null) {\n- if (!this.seenScopes.has(scope.id)) {\n- const currentScopes = this.blockScopes[this.blockScopes.length - 1]!;\n- this.seenScopes.add(scope.id);\n- currentScopes.scopes.push({\n- active: true,\n- scope,\n- });\n- }\n- }\n- }\n-\n- visitTerminalId(id: InstructionId): void {\n- this.visitId(id);\n- }\n-\n- visitTerminal(terminal: BlockTerminal): void {}\n-\n- visitImplicitTerminal(): void | null {}\n-\n- \/\/ no-ops\n- visitValue(value: InstructionValue): void {}\n- visitCase(test: void | null, block: void): void {}\n-}\n-\n-function getInstructionScope(instr: Instruction): ReactiveScope | null {\n- if (\n- instr.lvalue.place.identifier.scope !== null &&\n- isActive(instr, instr.lvalue.place.identifier.scope.range)\n- ) {\n- return instr.lvalue.place.identifier.scope;\n- } else {\n- for (const operand of eachInstructionOperand(instr)) {\n- if (\n- operand.identifier.scope !== null &&\n- isActive(instr, operand.identifier.scope.range)\n- ) {\n- return operand.identifier.scope;\n- }\n- }\n- }\n- return null;\n-}\n-\n-function isActive(instr: Instruction, range: MutableRange): boolean {\n- return instr.id >= range.start && instr.id < range.end;\n-}\ndiff --git a\/compiler\/forget\/src\/ReactiveScopes\/index.ts b\/compiler\/forget\/src\/ReactiveScopes\/index.ts\nindex 5c032071e8..b848df584e 100644\n--- a\/compiler\/forget\/src\/ReactiveScopes\/index.ts\n+++ b\/compiler\/forget\/src\/ReactiveScopes\/index.ts\n@@ -8,10 +8,8 @@\n export { alignReactiveScopesToBlockScopes } from \".\/AlignReactiveScopesToBlockScopes\";\n export { buildReactiveBlocks } from \".\/BuildReactiveBlocks\";\n export { buildReactiveFunction } from \".\/BuildReactiveFunction\";\n-export { buildReactiveFunction as buildReactiveFunctionWithoutScopes } from \".\/BuildReactiveFunctionWithoutScopes\";\n export { codegenReactiveFunction } from \".\/CodegenReactiveFunction\";\n export { flattenReactiveLoops } from \".\/FlattenReactiveLoops\";\n-export { inferReactiveScopes } from \".\/InferReactiveScopes\";\n export { inferReactiveScopeVariables } from \".\/InferReactiveScopeVariables\";\n export { mergeOverlappingReactiveScopes } from \".\/MergeOverlappingReactiveScopes\";\n export { printReactiveFunction } from \".\/PrintReactiveFunction\";\ndiff --git a\/compiler\/forget\/src\/__tests__\/hir-test.ts b\/compiler\/forget\/src\/__tests__\/hir-test.ts\nindex c0d6c13f0e..13e4c364c0 100644\n--- a\/compiler\/forget\/src\/__tests__\/hir-test.ts\n+++ b\/compiler\/forget\/src\/__tests__\/hir-test.ts\n@@ -13,7 +13,6 @@ import traverse from \"@babel\/traverse\";\n import { wasmFolder } from \"@hpcc-js\/wasm\";\n import path from \"path\";\n import prettier from \"prettier\";\n-import { flags } from \"..\/CompilerFlags\";\n import { compile } from \"..\/CompilerPipeline\";\n import { toggleLogging } from \"..\/Utils\/logger\";\n import generateTestsFromFixtures from \".\/test-utils\/generateTestsFromFixtures\";\n@@ -31,9 +30,6 @@ wasmFolder(\n const Pragma_RE = \/\\\/\\\/\\s*@enable\$(\\w+)\$$\/gm;\n \n describe(\"React Forget (HIR version)\", () => {\n- flags.enableNewReactiveFunctionBuilder =\n- String(process.env[\"ENABLE_NEW_BUILDER\"]) === \"1\";\n-\n generateTestsFromFixtures(\n path.join(__dirname, \"fixtures\", \"hir\"),\n (input, file, options) => {\ndiff --git a\/compiler\/forget\/src\/index.ts b\/compiler\/forget\/src\/index.ts\nindex fe64c5b104..ebff2493c9 100644\n--- a\/compiler\/forget\/src\/index.ts\n+++ b\/compiler\/forget\/src\/index.ts\n@@ -20,10 +20,9 @@ import codegen from \".\/HIR\/Codegen\";\n import { Environment } from \".\/HIR\/HIRBuilder\";\n import printHIR, { printFunction } from \".\/HIR\/PrintHIR\";\n import { inferMutableRanges, inferReferenceEffects } from \".\/Inference\";\n-import { buildReactiveFunction } from \".\/ReactiveScopes\/BuildReactiveFunctionWithoutScopes\";\n+import { buildReactiveFunction } from \".\/ReactiveScopes\/BuildReactiveFunction\";\n import { codegenReactiveFunction } from \".\/ReactiveScopes\/CodegenReactiveFunction\";\n import { flattenReactiveLoops } from \".\/ReactiveScopes\/FlattenReactiveLoops\";\n-import { inferReactiveScopes } from \".\/ReactiveScopes\/InferReactiveScopes\";\n import { inferReactiveScopeVariables } from \".\/ReactiveScopes\/InferReactiveScopeVariables\";\n import { printReactiveFunction } from \".\/ReactiveScopes\/PrintReactiveFunction\";\n import { propagateScopeDependencies } from \".\/ReactiveScopes\/PropagateScopeDependencies\";\n@@ -65,7 +64,6 @@ export const HIR = {\n Environment,\n flattenReactiveLoops,\n inferMutableRanges,\n- inferReactiveScopes,\n inferReactiveScopeVariables,\n inferReferenceEffects,\n inferTypes,\n","files":[{"status":"M","path":"compiler\/forget\/src\/CompilerFlags.ts"},{"status":"M","path":"compiler\/forget\/src\/CompilerPipeline.ts"},{"status":"D","path":"compiler\/forget\/src\/HIR\/ReactiveFunctionVisitor.ts"},{"status":"M","path":"compiler\/forget\/src\/ReactiveScopes\/BuildReactiveFunction.ts"},{"status":"D","path":"compiler\/forget\/src\/ReactiveScopes\/BuildReactiveFunctionWithoutScopes.ts"},{"status":"D","path":"compiler\/forget\/src\/ReactiveScopes\/InferReactiveScopes.ts"},{"status":"M","path":"compiler\/forget\/src\/ReactiveScopes\/index.ts"},{"status":"M","path":"compiler\/forget\/src\/__tests__\/hir-test.ts"},{"status":"M","path":"compiler\/forget\/src\/index.ts"}],"body":"","commit":{"authorEmail":"joesavona@fb.com","authoredAt":"2023-01-12T11:06:40-08:00","subject":"Switch to new BuildReactiveFunction passes","revision":"da21e9c52507da43d9bce1e45e7c623722f8d664","shortRevision":"da21e9c525","authorName":"Joe Savona"}}

dillon1000/react

Files changed