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merged 2 commits into from
Jun 18, 2025
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[compiler] Preserve Create effects, guarantee effects initialize once #33558

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963970b
[compiler] Fix <ValidateMemoization>
josephsavona Jun 18, 2025
fc2c4f2
[compiler] Preserve Create effects, guarantee effects initialize once
josephsavona Jun 18, 2025
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14 changes: 13 additions & 1 deletion compiler/packages/babel-plugin-react-compiler/src/Inference/AnalyseFunctions.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -20,10 +20,11 @@ import {inferReactiveScopeVariables} from '../ReactiveScopes';
import {rewriteInstructionKindsBasedOnReassignment} from '../SSA';
import {inferMutableRanges} from './InferMutableRanges';
import inferReferenceEffects from './InferReferenceEffects';
import {assertExhaustive} from '../Utils/utils';
import {assertExhaustive, retainWhere} from '../Utils/utils';
import {inferMutationAliasingEffects} from './InferMutationAliasingEffects';
import {inferFunctionExpressionAliasingEffectsSignature} from './InferFunctionExpressionAliasingEffectsSignature';
import {inferMutationAliasingRanges} from './InferMutationAliasingRanges';
import {hashEffect} from './AliasingEffects';

export default function analyseFunctions(func: HIRFunction): void {
for (const [_, block] of func.body.blocks) {
Expand Down Expand Up @@ -81,6 +82,17 @@ function lowerWithMutationAliasing(fn: HIRFunction): void {
fn.aliasingEffects ??= [];
fn.aliasingEffects?.push(...effects);
}
if (fn.aliasingEffects != null) {
const seen = new Set<string>();
retainWhere(fn.aliasingEffects, effect => {
const hash = hashEffect(effect);
if (seen.has(hash)) {
return false;
}
seen.add(hash);
return true;
});
}

/**
* Phase 2: populate the Effect of each context variable to use in inferring
Expand Down
102 changes: 75 additions & 27 deletions compiler/packages/babel-plugin-react-compiler/src/Inference/InferMutationAliasingEffects.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -362,6 +362,11 @@ function inferBlock(
} else if (terminal.kind === 'maybe-throw') {
const handlerParam = context.catchHandlers.get(terminal.handler);
if (handlerParam != null) {
CompilerError.invariant(state.kind(handlerParam) != null, {
reason:
'Expected catch binding to be intialized with a DeclareLocal Catch instruction',
loc: terminal.loc,
});
const effects: Array<AliasingEffect> = [];
for (const instr of block.instructions) {
if (
Expand Down Expand Up @@ -476,14 +481,14 @@ function applySignature(
* Track which values we've already aliased once, so that we can switch to
* appendAlias() for subsequent aliases into the same value
*/
const aliased = new Set<IdentifierId>();
const initialized = new Set<IdentifierId>();

if (DEBUG) {
console.log(printInstruction(instruction));
}

for (const effect of signature.effects) {
applyEffect(context, state, effect, aliased, effects);
applyEffect(context, state, effect, initialized, effects);
}
if (DEBUG) {
console.log(
Expand All @@ -508,7 +513,7 @@ function applyEffect(
context: Context,
state: InferenceState,
_effect: AliasingEffect,
aliased: Set<IdentifierId>,
initialized: Set<IdentifierId>,
effects: Array<AliasingEffect>,
): void {
const effect = context.internEffect(_effect);
Expand All @@ -524,6 +529,13 @@ function applyEffect(
break;
}
case 'Create': {
CompilerError.invariant(!initialized.has(effect.into.identifier.id), {
reason: `Cannot re-initialize variable within an instruction`,
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Makes sense! Does something else also ensure that we don't have duplicate Create / CreateFroms for the same Identifier / IdentifierId across multiple instructions (i.e. StoreLocals to the same lvalue), or is that case not an issue?

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There is a todo for this in InferMutationAliasingRanges. Only two fixtures fail if i enable that invariant though, for understandable reasons, so in general we are preserving this guarantee.

description: `Re-initialized ${printPlace(effect.into)} in ${printAliasingEffect(effect)}`,
loc: effect.into.loc,
});
initialized.add(effect.into.identifier.id);

let value = context.effectInstructionValueCache.get(effect);
if (value == null) {
value = {
Expand All @@ -538,6 +550,7 @@ function applyEffect(
reason: new Set([effect.reason]),
});
state.define(effect.into, value);
effects.push(effect);
break;
}
case 'ImmutableCapture': {
Expand All @@ -555,6 +568,13 @@ function applyEffect(
break;
}
case 'CreateFrom': {
CompilerError.invariant(!initialized.has(effect.into.identifier.id), {
reason: `Cannot re-initialize variable within an instruction`,
description: `Re-initialized ${printPlace(effect.into)} in ${printAliasingEffect(effect)}`,
loc: effect.into.loc,
});
initialized.add(effect.into.identifier.id);

const fromValue = state.kind(effect.from);
let value = context.effectInstructionValueCache.get(effect);
if (value == null) {
Expand All @@ -573,10 +593,21 @@ function applyEffect(
switch (fromValue.kind) {
case ValueKind.Primitive:
case ValueKind.Global: {
// no need to track this data flow
effects.push({
kind: 'Create',
value: fromValue.kind,
into: effect.into,
reason: [...fromValue.reason][0] ?? ValueReason.Other,
});
break;
}
case ValueKind.Frozen: {
effects.push({
kind: 'Create',
value: fromValue.kind,
into: effect.into,
reason: [...fromValue.reason][0] ?? ValueReason.Other,
});
applyEffect(
context,
state,
Expand All @@ -585,7 +616,7 @@ function applyEffect(
from: effect.from,
into: effect.into,
},
aliased,
initialized,
effects,
);
break;
Expand All @@ -597,6 +628,13 @@ function applyEffect(
break;
}
case 'CreateFunction': {
CompilerError.invariant(!initialized.has(effect.into.identifier.id), {
reason: `Cannot re-initialize variable within an instruction`,
description: `Re-initialized ${printPlace(effect.into)} in ${printAliasingEffect(effect)}`,
loc: effect.into.loc,
});
initialized.add(effect.into.identifier.id);

effects.push(effect);
/**
* We consider the function mutable if it has any mutable context variables or
Expand Down Expand Up @@ -653,14 +691,22 @@ function applyEffect(
from: capture,
into: effect.into,
},
aliased,
initialized,
effects,
);
}
break;
}
case 'Alias':
case 'Capture': {
CompilerError.invariant(
effect.kind === 'Capture' || initialized.has(effect.into.identifier.id),
{
reason: `Expected destination value to already be initialized within this instruction for Alias effect`,
description: `Destination ${printPlace(effect.into)} is not initialized in this instruction`,
loc: effect.into.loc,
},
);
/*
* Capture describes potential information flow: storing a pointer to one value
* within another. If the destination is not mutable, or the source value has
Expand Down Expand Up @@ -698,7 +744,7 @@ function applyEffect(
from: effect.from,
into: effect.into,
},
aliased,
initialized,
effects,
);
break;
Expand All @@ -714,6 +760,13 @@ function applyEffect(
break;
}
case 'Assign': {
CompilerError.invariant(!initialized.has(effect.into.identifier.id), {
reason: `Cannot re-initialize variable within an instruction`,
description: `Re-initialized ${printPlace(effect.into)} in ${printAliasingEffect(effect)}`,
loc: effect.into.loc,
});
initialized.add(effect.into.identifier.id);

/*
* Alias represents potential pointer aliasing. If the type is a global,
* a primitive (copy-on-write semantics) then we can prune the effect
Expand All @@ -730,7 +783,7 @@ function applyEffect(
from: effect.from,
into: effect.into,
},
aliased,
initialized,
effects,
);
let value = context.effectInstructionValueCache.get(effect);
Expand Down Expand Up @@ -768,12 +821,7 @@ function applyEffect(
break;
}
default: {
if (aliased.has(effect.into.identifier.id)) {
state.appendAlias(effect.into, effect.from);
} else {
aliased.add(effect.into.identifier.id);
state.alias(effect.into, effect.from);
}
state.assign(effect.into, effect.from);
effects.push(effect);
break;
}
Expand Down Expand Up @@ -826,11 +874,11 @@ function applyEffect(
context,
state,
{kind: 'MutateTransitiveConditionally', value: effect.function},
aliased,
initialized,
effects,
);
for (const signatureEffect of signatureEffects) {
applyEffect(context, state, signatureEffect, aliased, effects);
applyEffect(context, state, signatureEffect, initialized, effects);
}
break;
}
Expand Down Expand Up @@ -858,7 +906,7 @@ function applyEffect(
console.log('apply aliasing signature effects');
}
for (const signatureEffect of signatureEffects) {
applyEffect(context, state, signatureEffect, aliased, effects);
applyEffect(context, state, signatureEffect, initialized, effects);
}
} else if (effect.signature != null) {
if (DEBUG) {
Expand All @@ -873,7 +921,7 @@ function applyEffect(
effect.loc,
);
for (const legacyEffect of legacyEffects) {
applyEffect(context, state, legacyEffect, aliased, effects);
applyEffect(context, state, legacyEffect, initialized, effects);
}
} else {
if (DEBUG) {
Expand All @@ -888,7 +936,7 @@ function applyEffect(
value: ValueKind.Mutable,
reason: ValueReason.Other,
},
aliased,
initialized,
effects,
);
/*
Expand All @@ -911,21 +959,21 @@ function applyEffect(
kind: 'MutateTransitiveConditionally',
value: operand,
},
aliased,
initialized,
effects,
);
}
const mutateIterator =
arg.kind === 'Spread' ? conditionallyMutateIterator(operand) : null;
if (mutateIterator) {
applyEffect(context, state, mutateIterator, aliased, effects);
applyEffect(context, state, mutateIterator, initialized, effects);
}
applyEffect(
context,
state,
// OK: recording information flow
{kind: 'Alias', from: operand, into: effect.into},
aliased,
initialized,
effects,
);
for (const otherArg of [
Expand Down Expand Up @@ -953,7 +1001,7 @@ function applyEffect(
from: operand,
into: other,
},
aliased,
initialized,
effects,
);
}
Expand Down Expand Up @@ -1009,7 +1057,7 @@ function applyEffect(
suggestions: null,
},
},
aliased,
initialized,
effects,
);
}
Expand All @@ -1028,7 +1076,7 @@ function applyEffect(
suggestions: null,
},
},
aliased,
initialized,
effects,
);
} else {
Expand Down Expand Up @@ -1059,7 +1107,7 @@ function applyEffect(
suggestions: null,
},
},
aliased,
initialized,
effects,
);
}
Expand Down Expand Up @@ -1166,7 +1214,7 @@ class InferenceState {
}

// Updates the value at @param place to point to the same value as @param value.
alias(place: Place, value: Place): void {
assign(place: Place, value: Place): void {
const values = this.#variables.get(value.identifier.id);
CompilerError.invariant(values != null, {
reason: `[InferMutationAliasingEffects] Expected value for identifier to be initialized`,
Expand Down
13 changes: 4 additions & 9 deletions ...fixtures/compiler/new-mutability/todo-control-flow-sensitive-mutation.expect.md
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Original file line number Diff line number Diff line change
Expand Up @@ -23,14 +23,9 @@ function Component({a, b, c}: {a: number; b: number; c: number}) {

return (
<>
<ValidateMemoization inputs={[a, b, c]} output={x} alwaysCheck={true} />;
<ValidateMemoization inputs={[a, b, c]} output={x} />;
{/* TODO: should only depend on c */}
<ValidateMemoization
inputs={[a, b, c]}
output={x[0]}
alwaysCheck={true}
/>
;
<ValidateMemoization inputs={[a, b, c]} output={x[0]} />;
</>
);
}
Expand Down Expand Up @@ -98,7 +93,7 @@ function Component(t0) {
}
let t3;
if ($[9] !== t2 || $[10] !== x) {
t3 = <ValidateMemoization inputs={t2} output={x} alwaysCheck={true} />;
t3 = <ValidateMemoization inputs={t2} output={x} />;
$[9] = t2;
$[10] = x;
$[11] = t3;
Expand All @@ -117,7 +112,7 @@ function Component(t0) {
}
let t5;
if ($[16] !== t4 || $[17] !== x[0]) {
t5 = <ValidateMemoization inputs={t4} output={x[0]} alwaysCheck={true} />;
t5 = <ValidateMemoization inputs={t4} output={x[0]} />;
$[16] = t4;
$[17] = x[0];
$[18] = t5;
Expand Down
9 changes: 2 additions & 7 deletions ...r/src/__tests__/fixtures/compiler/new-mutability/todo-control-flow-sensitive-mutation.tsx
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Expand Up @@ -19,14 +19,9 @@ function Component({a, b, c}: {a: number; b: number; c: number}) {

return (
<>
<ValidateMemoization inputs={[a, b, c]} output={x} alwaysCheck={true} />;
<ValidateMemoization inputs={[a, b, c]} output={x} />;
{/* TODO: should only depend on c */}
<ValidateMemoization
inputs={[a, b, c]}
output={x[0]}
alwaysCheck={true}
/>
;
<ValidateMemoization inputs={[a, b, c]} output={x[0]} />;
</>
);
}
Expand Down
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