[compiler] Effect inference across signatures and user-provided callbacks #33384
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…acks This ties all the ideas together, showing the promise of the new inference. When applying effects, when we encounter an Apply effect we now check to see if the function we're calling is a locally defined FunctionExpression. If so, we construct a signature for it on the fly (we already have created the effects in AnalyzeFunctions), substitute in the args to get a set of effects we can apply, and then recursively apply those effects. This required adding an ability for signatures to declare additional temporary places that they can reference. For example, Array.prototype.map needs a temporary to represent the items it extracts from the receiver array, and another temporary for the result of calling the user-provided function. This also meant adding a `CreateFunction` effect which a) allows us to preserve the FunctionExpression value in the inference state (the previous Create effect meant we just created a dummy ObjectExpression) and b) allows dynamically constructing the ValueKind of the function based on whether it actually captures any mutable values. Lots of other little fixes as well, such as changing function related effects (and PropertyLoad) to use Alias instead of Capture so that subsequent mutations of the output count as mutations of the input. [ghstack-poisoned]
This was referenced May 30, 2025
This was referenced May 30, 2025
josephsavona
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May 30, 2025
…acks This ties all the ideas together, showing the promise of the new inference. When applying effects, when we encounter an Apply effect we now check to see if the function we're calling is a locally defined FunctionExpression. If so, we construct a signature for it on the fly (we already have created the effects in AnalyzeFunctions), substitute in the args to get a set of effects we can apply, and then recursively apply those effects. This required adding an ability for signatures to declare additional temporary places that they can reference. For example, Array.prototype.map needs a temporary to represent the items it extracts from the receiver array, and another temporary for the result of calling the user-provided function. This also meant adding a `CreateFunction` effect which a) allows us to preserve the FunctionExpression value in the inference state (the previous Create effect meant we just created a dummy ObjectExpression) and b) allows dynamically constructing the ValueKind of the function based on whether it actually captures any mutable values. Lots of other little fixes as well, such as changing function related effects (and PropertyLoad) to use Alias instead of Capture so that subsequent mutations of the output count as mutations of the input. ghstack-source-id: 93c3bc3 Pull Request resolved: #33384
josephsavona
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May 30, 2025
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| if ($[0] !== props.a) { | ||
| t0 = { a: props.a }; | ||
| $[0] = props.a; | ||
| $[1] = t0; | ||
| } else { | ||
| t0 = $[1]; | ||
| } | ||
| const item = t0; | ||
| let t1; | ||
| if ($[2] !== item) { | ||
| t1 = [item]; | ||
| $[2] = item; | ||
| $[3] = t1; | ||
| } else { | ||
| t1 = $[3]; | ||
| } | ||
| const items = t1; | ||
| let t2; | ||
| if ($[4] !== items) { | ||
| t2 = items.map(_temp); | ||
| $[4] = items; | ||
| $[5] = t2; | ||
| } else { | ||
| t2 = $[5]; | ||
| } | ||
| const mapped = t2; |
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In the previous model, these are all grouped together. the map callback captures its argument so we consider that mutated, so our mutableIfOperandsAreMutable() check thinks the callback is mutating.
Whereas the new model understands that the param isn't mutated, it's just captured into the output.
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Of course, we should still be collapsing these consecutive scopes :-)
josephsavona
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May 30, 2025
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| let ref; | ||
| if (props.foo) { | ||
| ref = ref1; | ||
| } else { | ||
| ref = ref2; | ||
| } |
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the previous model unnecessarily groups this block into a reactive scope, but the output here is correct and more optimal
…vided callbacks" This ties all the ideas together, showing the promise of the new inference. When applying effects, when we encounter an Apply effect we now check to see if the function we're calling is a locally defined FunctionExpression. If so, we construct a signature for it on the fly (we already have created the effects in AnalyzeFunctions), substitute in the args to get a set of effects we can apply, and then recursively apply those effects. This required adding an ability for signatures to declare additional temporary places that they can reference. For example, Array.prototype.map needs a temporary to represent the items it extracts from the receiver array, and another temporary for the result of calling the user-provided function. This also meant adding a `CreateFunction` effect which a) allows us to preserve the FunctionExpression value in the inference state (the previous Create effect meant we just created a dummy ObjectExpression) and b) allows dynamically constructing the ValueKind of the function based on whether it actually captures any mutable values. Lots of other little fixes as well, such as changing function related effects (and PropertyLoad) to use Alias instead of Capture so that subsequent mutations of the output count as mutations of the input. [ghstack-poisoned]
…vided callbacks" This ties all the ideas together, showing the promise of the new inference. When applying effects, when we encounter an Apply effect we now check to see if the function we're calling is a locally defined FunctionExpression. If so, we construct a signature for it on the fly (we already have created the effects in AnalyzeFunctions), substitute in the args to get a set of effects we can apply, and then recursively apply those effects. This required adding an ability for signatures to declare additional temporary places that they can reference. For example, Array.prototype.map needs a temporary to represent the items it extracts from the receiver array, and another temporary for the result of calling the user-provided function. This also meant adding a `CreateFunction` effect which a) allows us to preserve the FunctionExpression value in the inference state (the previous Create effect meant we just created a dummy ObjectExpression) and b) allows dynamically constructing the ValueKind of the function based on whether it actually captures any mutable values. Lots of other little fixes as well, such as changing function related effects (and PropertyLoad) to use Alias instead of Capture so that subsequent mutations of the output count as mutations of the input. [ghstack-poisoned]
…vided callbacks" This ties all the ideas together, showing the promise of the new inference. When applying effects, when we encounter an Apply effect we now check to see if the function we're calling is a locally defined FunctionExpression. If so, we construct a signature for it on the fly (we already have created the effects in AnalyzeFunctions), substitute in the args to get a set of effects we can apply, and then recursively apply those effects. This required adding an ability for signatures to declare additional temporary places that they can reference. For example, Array.prototype.map needs a temporary to represent the items it extracts from the receiver array, and another temporary for the result of calling the user-provided function. This also meant adding a `CreateFunction` effect which a) allows us to preserve the FunctionExpression value in the inference state (the previous Create effect meant we just created a dummy ObjectExpression) and b) allows dynamically constructing the ValueKind of the function based on whether it actually captures any mutable values. Lots of other little fixes as well, such as changing function related effects (and PropertyLoad) to use Alias instead of Capture so that subsequent mutations of the output count as mutations of the input. [ghstack-poisoned]
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Stack from ghstack (oldest at bottom):
This ties all the ideas together, showing the promise of the new inference. When applying effects, when we encounter an Apply effect we now check to see if the function we're calling is a locally defined FunctionExpression. If so, we construct a signature for it on the fly (we already have created the effects in AnalyzeFunctions), substitute in the args to get a set of effects we can apply, and then recursively apply those effects.
This required adding an ability for signatures to declare additional temporary places that they can reference. For example, Array.prototype.map needs a temporary to represent the items it extracts from the receiver array, and another temporary for the result of calling the user-provided function.
This also meant adding a
CreateFunctioneffect which a) allows us to preserve the FunctionExpression value in the inference state (the previous Create effect meant we just created a dummy ObjectExpression) and b) allows dynamically constructing the ValueKind of the function based on whether it actually captures any mutable values.Lots of other little fixes as well, such as changing function related effects (and PropertyLoad) to use Alias instead of Capture so that subsequent mutations of the output count as mutations of the input.