490 lines
16 KiB
TypeScript
490 lines
16 KiB
TypeScript
import * as t from "@babel/types";
|
|
|
|
import type {
|
|
JavaScriptBindingProvenance,
|
|
JavaScriptModuleOrigin,
|
|
JavaScriptSemanticProperty,
|
|
JavaScriptSemanticValue,
|
|
} from "./javascriptSemanticIr.js";
|
|
import {
|
|
resolveSemanticBindingState,
|
|
type JavaScriptSemanticAnalysisState,
|
|
type JavaScriptSemanticBindingState,
|
|
} from "./javascriptSemanticState.js";
|
|
import {
|
|
compareCodePoints,
|
|
propertyName,
|
|
stringValue,
|
|
} from "./javascriptStaticAnalysisHelpers.js";
|
|
import {
|
|
reachSemanticValueLimit,
|
|
semanticLimitProvenance,
|
|
semanticOriginsProvenance,
|
|
semanticProvenance,
|
|
uniqueSemanticOrigins,
|
|
} from "./javascriptSemanticProvenance.js";
|
|
import {
|
|
semanticPrimitiveCandidates as primitiveCandidates,
|
|
semanticPrimitiveSet as primitiveSet,
|
|
semanticPrimitiveValue as primitiveValue,
|
|
} from "./javascriptSemanticPrimitives.js";
|
|
|
|
interface EvaluationContext {
|
|
readonly state: JavaScriptSemanticAnalysisState;
|
|
readonly bindings: ReadonlySet<string>;
|
|
readonly depth: number;
|
|
}
|
|
|
|
/** Evaluate one binding in the bounded constant-value lattice. */
|
|
export const evaluateSemanticBinding = (
|
|
binding: JavaScriptSemanticBindingState,
|
|
state: JavaScriptSemanticAnalysisState,
|
|
): JavaScriptSemanticValue =>
|
|
evaluateBinding(binding, { state, bindings: new Set(), depth: 0 });
|
|
|
|
/** Evaluate one arbitrary inert expression in the established lexical state. */
|
|
export const evaluateSemanticExpression = (
|
|
node: t.Node,
|
|
state: JavaScriptSemanticAnalysisState,
|
|
): JavaScriptSemanticValue =>
|
|
evaluateExpression(node, { state, bindings: new Set(), depth: 0 });
|
|
|
|
/** Follow module provenance through destructuring, members, and aliases. */
|
|
export const evaluateSemanticProvenance = (
|
|
binding: JavaScriptSemanticBindingState,
|
|
state: JavaScriptSemanticAnalysisState,
|
|
): JavaScriptBindingProvenance =>
|
|
provenanceForBinding(binding, { state, bindings: new Set(), depth: 0 });
|
|
|
|
const evaluateBinding = (
|
|
binding: JavaScriptSemanticBindingState,
|
|
context: EvaluationContext,
|
|
): JavaScriptSemanticValue => {
|
|
if (context.bindings.has(binding.bindingId))
|
|
return { status: "cycle", reason: `Alias cycle at ${binding.name}.` };
|
|
if (context.depth >= context.state.limits.maxValueDepth)
|
|
return limitValue(context.state, "maxValueDepth");
|
|
if (binding.initializers.length === 0)
|
|
return {
|
|
status: "unknown",
|
|
reason: `Binding ${binding.name} has no constant initializer.`,
|
|
};
|
|
if (binding.initializers.length > 1)
|
|
return {
|
|
status: "ambiguous",
|
|
reason: `Binding ${binding.name} has multiple possible assignments.`,
|
|
};
|
|
const initializer = binding.initializers[0];
|
|
if (initializer === undefined)
|
|
return { status: "unknown", reason: "Missing binding initializer." };
|
|
const nested = nestedContext(context, binding.bindingId);
|
|
return projectValue(
|
|
evaluateExpression(initializer.node, nested),
|
|
initializer.projection,
|
|
);
|
|
};
|
|
|
|
const evaluateExpression = (
|
|
node: t.Node,
|
|
context: EvaluationContext,
|
|
): JavaScriptSemanticValue => {
|
|
if (context.depth >= context.state.limits.maxValueDepth)
|
|
return limitValue(context.state, "maxValueDepth");
|
|
const literal = primitiveValue(node);
|
|
if (literal.found) return { status: "literal", value: literal.value };
|
|
if (t.isIdentifier(node)) {
|
|
const binding = resolveSemanticBindingState(context.state, node, node.name);
|
|
return binding === undefined
|
|
? { status: "unknown", reason: `Unbound identifier ${node.name}.` }
|
|
: evaluateBinding(binding, nestedContext(context));
|
|
}
|
|
if (t.isTemplateLiteral(node)) return evaluateTemplate(node, context);
|
|
if (t.isConditionalExpression(node))
|
|
return mergeValues(
|
|
[
|
|
evaluateExpression(node.consequent, nestedContext(context)),
|
|
evaluateExpression(node.alternate, nestedContext(context)),
|
|
],
|
|
context.state,
|
|
);
|
|
if (t.isLogicalExpression(node))
|
|
return mergeValues(
|
|
[
|
|
evaluateExpression(node.left, nestedContext(context)),
|
|
evaluateExpression(node.right, nestedContext(context)),
|
|
],
|
|
context.state,
|
|
);
|
|
if (t.isObjectExpression(node)) return evaluateObject(node, context);
|
|
if (t.isArrayExpression(node)) return evaluateArray(node, context);
|
|
if (t.isMemberExpression(node) || t.isOptionalMemberExpression(node))
|
|
return evaluateMember(node, context);
|
|
if (t.isBinaryExpression(node, { operator: "+" }))
|
|
return evaluateAddition(node, context);
|
|
if (t.isUnaryExpression(node)) return evaluateUnary(node, context);
|
|
if (
|
|
(t.isTSAsExpression(node) ||
|
|
t.isTSTypeAssertion(node) ||
|
|
t.isTSNonNullExpression(node)) &&
|
|
t.isExpression(node.expression)
|
|
)
|
|
return evaluateExpression(node.expression, nestedContext(context));
|
|
return { status: "unknown", reason: `Unsupported ${node.type} value.` };
|
|
};
|
|
|
|
const evaluateTemplate = (
|
|
node: t.TemplateLiteral,
|
|
context: EvaluationContext,
|
|
): JavaScriptSemanticValue => {
|
|
let candidates = [""];
|
|
for (let index = 0; index < node.quasis.length; index += 1) {
|
|
const quasi = node.quasis[index];
|
|
const text = quasi?.value.cooked ?? quasi?.value.raw ?? "";
|
|
candidates = candidates.map((prefix) => `${prefix}${text}`);
|
|
const expression = node.expressions[index];
|
|
if (expression === undefined) continue;
|
|
const values = primitiveCandidates(
|
|
evaluateExpression(expression, nestedContext(context)),
|
|
);
|
|
if (values === null)
|
|
return {
|
|
status: "unknown",
|
|
reason: "Template expression is not a bounded primitive.",
|
|
};
|
|
candidates = candidates.flatMap((prefix) =>
|
|
values.map((value) => `${prefix}${String(value)}`),
|
|
);
|
|
if (candidates.length > context.state.limits.maxUnionValues)
|
|
return limitValue(context.state, "maxUnionValues");
|
|
}
|
|
return primitiveSet(candidates, context.state);
|
|
};
|
|
|
|
const evaluateObject = (
|
|
node: t.ObjectExpression,
|
|
context: EvaluationContext,
|
|
): JavaScriptSemanticValue => {
|
|
const properties: JavaScriptSemanticProperty[] = [];
|
|
let unknownProperties = false;
|
|
let omittedProperties: number | null = 0;
|
|
for (const property of node.properties) {
|
|
if (t.isSpreadElement(property)) {
|
|
unknownProperties = true;
|
|
omittedProperties = null;
|
|
continue;
|
|
}
|
|
if (property.computed) {
|
|
unknownProperties = true;
|
|
if (omittedProperties !== null) omittedProperties += 1;
|
|
continue;
|
|
}
|
|
const name = propertyName(property.key);
|
|
if (name === "" || !t.isObjectProperty(property)) {
|
|
unknownProperties = true;
|
|
if (omittedProperties !== null) omittedProperties += 1;
|
|
continue;
|
|
}
|
|
if (properties.length >= context.state.limits.maxObjectProperties) {
|
|
reachSemanticValueLimit(context.state, "maxObjectProperties");
|
|
unknownProperties = true;
|
|
if (omittedProperties !== null) omittedProperties += 1;
|
|
continue;
|
|
}
|
|
properties.push({
|
|
name,
|
|
value: evaluateExpression(property.value, nestedContext(context)),
|
|
});
|
|
}
|
|
properties.sort((left, right) => compareCodePoints(left.name, right.name));
|
|
return {
|
|
status: "object",
|
|
properties,
|
|
unknownProperties,
|
|
omittedProperties,
|
|
};
|
|
};
|
|
|
|
const evaluateArray = (
|
|
node: t.ArrayExpression,
|
|
context: EvaluationContext,
|
|
): JavaScriptSemanticValue => {
|
|
const items: JavaScriptSemanticValue[] = [];
|
|
let unknownItems = false;
|
|
let omittedItems: number | null = 0;
|
|
for (const element of node.elements) {
|
|
if (t.isSpreadElement(element)) {
|
|
unknownItems = true;
|
|
omittedItems = null;
|
|
continue;
|
|
}
|
|
if (element === null) {
|
|
unknownItems = true;
|
|
if (omittedItems !== null) omittedItems += 1;
|
|
continue;
|
|
}
|
|
if (items.length >= context.state.limits.maxObjectProperties) {
|
|
reachSemanticValueLimit(context.state, "maxObjectProperties");
|
|
unknownItems = true;
|
|
if (omittedItems !== null) omittedItems += 1;
|
|
continue;
|
|
}
|
|
items.push(evaluateExpression(element, nestedContext(context)));
|
|
}
|
|
return { status: "array", items, unknownItems, omittedItems };
|
|
};
|
|
|
|
const evaluateMember = (
|
|
node: t.MemberExpression | t.OptionalMemberExpression,
|
|
context: EvaluationContext,
|
|
): JavaScriptSemanticValue => {
|
|
if (!t.isNode(node.object))
|
|
return { status: "unknown", reason: "Unsupported member base." };
|
|
const key = memberKey(node);
|
|
if (key === undefined)
|
|
return { status: "unknown", reason: "Dynamic member key." };
|
|
return projectValue(evaluateExpression(node.object, nestedContext(context)), [
|
|
key,
|
|
]);
|
|
};
|
|
|
|
const evaluateAddition = (
|
|
node: t.BinaryExpression,
|
|
context: EvaluationContext,
|
|
): JavaScriptSemanticValue => {
|
|
const left = primitiveCandidates(
|
|
evaluateExpression(node.left, nestedContext(context)),
|
|
);
|
|
const right = primitiveCandidates(
|
|
evaluateExpression(node.right, nestedContext(context)),
|
|
);
|
|
if (left === null || right === null)
|
|
return { status: "unknown", reason: "Non-primitive addition." };
|
|
const values = left.flatMap((leftValue) =>
|
|
right.map((rightValue) =>
|
|
typeof leftValue === "number" && typeof rightValue === "number"
|
|
? leftValue + rightValue
|
|
: `${String(leftValue)}${String(rightValue)}`,
|
|
),
|
|
);
|
|
return primitiveSet(values, context.state);
|
|
};
|
|
|
|
const evaluateUnary = (
|
|
node: t.UnaryExpression,
|
|
context: EvaluationContext,
|
|
): JavaScriptSemanticValue => {
|
|
const argument = primitiveCandidates(
|
|
evaluateExpression(node.argument, nestedContext(context)),
|
|
);
|
|
if (argument === null)
|
|
return { status: "unknown", reason: "Non-primitive unary operand." };
|
|
if (node.operator === "!")
|
|
return primitiveSet(
|
|
argument.map((value) => !value),
|
|
context.state,
|
|
);
|
|
if (node.operator === "+")
|
|
return primitiveSet(
|
|
argument.map((value) => Number(value)),
|
|
context.state,
|
|
);
|
|
if (node.operator === "-")
|
|
return primitiveSet(
|
|
argument.map((value) => -Number(value)),
|
|
context.state,
|
|
);
|
|
return { status: "unknown", reason: `Unsupported unary ${node.operator}.` };
|
|
};
|
|
|
|
const projectValue = (
|
|
value: JavaScriptSemanticValue,
|
|
projection: readonly (string | number | null)[],
|
|
): JavaScriptSemanticValue => {
|
|
let current = value;
|
|
for (const key of projection) {
|
|
if (key === null)
|
|
return {
|
|
status: "unknown",
|
|
reason: "Cannot project a dynamic property.",
|
|
};
|
|
if (current.status === "object" && typeof key === "string") {
|
|
const property = current.properties.find(({ name }) => name === key);
|
|
if (property === undefined)
|
|
return {
|
|
status: current.unknownProperties ? "unknown" : "unknown",
|
|
reason: `Object property ${key} was not observed.`,
|
|
};
|
|
current = property.value;
|
|
} else if (current.status === "array" && typeof key === "number") {
|
|
const item = current.items[key];
|
|
if (item === undefined)
|
|
return {
|
|
status: "unknown",
|
|
reason: `Array item ${String(key)} missing.`,
|
|
};
|
|
current = item;
|
|
} else
|
|
return {
|
|
status: "unknown",
|
|
reason: `Cannot project ${String(key)} from ${current.status}.`,
|
|
};
|
|
}
|
|
return current;
|
|
};
|
|
|
|
const provenanceForBinding = (
|
|
binding: JavaScriptSemanticBindingState,
|
|
context: EvaluationContext,
|
|
): JavaScriptBindingProvenance => {
|
|
if (context.bindings.has(binding.bindingId))
|
|
return semanticProvenance("cycle", [], `Alias cycle at ${binding.name}.`);
|
|
if (context.depth >= context.state.limits.maxValueDepth)
|
|
return semanticLimitProvenance(context.state, "maxValueDepth");
|
|
if (binding.directOrigins.length > 0)
|
|
return semanticOriginsProvenance(binding.directOrigins, context.state);
|
|
if (binding.initializers.length === 0)
|
|
return semanticProvenance("local", [], null);
|
|
if (binding.initializers.length > 1)
|
|
return semanticProvenance(
|
|
"ambiguous",
|
|
[],
|
|
`Binding ${binding.name} has multiple possible assignments.`,
|
|
);
|
|
const initializer = binding.initializers[0];
|
|
if (initializer === undefined)
|
|
return semanticProvenance("unknown", [], "Missing binding initializer.");
|
|
if (initializer.projection.includes(null))
|
|
return semanticProvenance("unknown", [], "Dynamic provenance projection.");
|
|
const resolved = provenanceForExpression(
|
|
initializer.node,
|
|
nestedContext(context, binding.bindingId),
|
|
);
|
|
if (resolved.status !== "module" || initializer.projection.length === 0)
|
|
return resolved;
|
|
return semanticOriginsProvenance(
|
|
resolved.origins.map((origin) => ({
|
|
...origin,
|
|
importedPath: [
|
|
...origin.importedPath,
|
|
...initializer.projection.map((segment) => String(segment)),
|
|
],
|
|
})),
|
|
context.state,
|
|
);
|
|
};
|
|
|
|
const provenanceForExpression = (
|
|
node: t.Node,
|
|
context: EvaluationContext,
|
|
): JavaScriptBindingProvenance => {
|
|
const required = requireOrigin(node);
|
|
if (required !== undefined)
|
|
return semanticOriginsProvenance([required], context.state);
|
|
if (t.isIdentifier(node)) {
|
|
const binding = resolveSemanticBindingState(context.state, node, node.name);
|
|
return binding === undefined
|
|
? semanticProvenance("unknown", [], `Unbound identifier ${node.name}.`)
|
|
: provenanceForBinding(binding, nestedContext(context));
|
|
}
|
|
if (t.isMemberExpression(node) || t.isOptionalMemberExpression(node)) {
|
|
if (!t.isNode(node.object))
|
|
return semanticProvenance("unknown", [], "Unsupported member base.");
|
|
const member = memberKey(node);
|
|
if (typeof member !== "string")
|
|
return semanticProvenance("unknown", [], "Dynamic provenance member.");
|
|
const base = provenanceForExpression(node.object, nestedContext(context));
|
|
return base.status !== "module"
|
|
? base
|
|
: semanticOriginsProvenance(
|
|
base.origins.map((origin) => ({
|
|
...origin,
|
|
importedPath: [...origin.importedPath, member],
|
|
})),
|
|
context.state,
|
|
);
|
|
}
|
|
if (t.isConditionalExpression(node) || t.isLogicalExpression(node)) {
|
|
const left = t.isConditionalExpression(node) ? node.consequent : node.left;
|
|
const right = t.isConditionalExpression(node) ? node.alternate : node.right;
|
|
const candidates = [
|
|
provenanceForExpression(left, nestedContext(context)),
|
|
provenanceForExpression(right, nestedContext(context)),
|
|
];
|
|
const origins = candidates.flatMap((candidate) => candidate.origins);
|
|
return origins.length > 0
|
|
? semanticProvenance(
|
|
"ambiguous",
|
|
uniqueSemanticOrigins(origins),
|
|
"Multiple module origins.",
|
|
)
|
|
: semanticProvenance(
|
|
"unknown",
|
|
[],
|
|
"Conditional provenance is unresolved.",
|
|
);
|
|
}
|
|
return semanticProvenance("local", [], null);
|
|
};
|
|
|
|
const requireOrigin = (node: t.Node): JavaScriptModuleOrigin | undefined => {
|
|
if (t.isMemberExpression(node) || t.isOptionalMemberExpression(node)) {
|
|
if (!t.isNode(node.object)) return undefined;
|
|
const nested = requireOrigin(node.object);
|
|
const member = memberKey(node);
|
|
return nested === undefined || typeof member !== "string"
|
|
? undefined
|
|
: { ...nested, importedPath: [...nested.importedPath, member] };
|
|
}
|
|
if (
|
|
!t.isCallExpression(node) ||
|
|
!t.isIdentifier(node.callee, { name: "require" })
|
|
)
|
|
return undefined;
|
|
const specifier = stringValue(node.arguments[0]);
|
|
return specifier === undefined ? undefined : { specifier, importedPath: [] };
|
|
};
|
|
|
|
const mergeValues = (
|
|
values: readonly JavaScriptSemanticValue[],
|
|
state: JavaScriptSemanticAnalysisState,
|
|
): JavaScriptSemanticValue => {
|
|
const primitives = values.flatMap(
|
|
(value) => primitiveCandidates(value) ?? [],
|
|
);
|
|
return primitives.length === values.length ||
|
|
values.every(
|
|
(value) => value.status === "union" || value.status === "literal",
|
|
)
|
|
? primitiveSet(primitives, state)
|
|
: { status: "ambiguous", reason: "Branches have incompatible values." };
|
|
};
|
|
|
|
const memberKey = (
|
|
node: t.MemberExpression | t.OptionalMemberExpression,
|
|
): string | number | undefined => {
|
|
if (!node.computed) return propertyName(node.property) || undefined;
|
|
if (t.isStringLiteral(node.property) || t.isNumericLiteral(node.property))
|
|
return node.property.value;
|
|
return undefined;
|
|
};
|
|
|
|
const limitValue = (
|
|
state: JavaScriptSemanticAnalysisState,
|
|
limit: "maxValueDepth" | "maxUnionValues",
|
|
): JavaScriptSemanticValue => {
|
|
reachSemanticValueLimit(state, limit);
|
|
return { status: "limit-reached", reason: `${limit} reached.` };
|
|
};
|
|
|
|
const nestedContext = (
|
|
context: EvaluationContext,
|
|
bindingId?: string,
|
|
): EvaluationContext => ({
|
|
state: context.state,
|
|
depth: context.depth + 1,
|
|
bindings:
|
|
bindingId === undefined
|
|
? context.bindings
|
|
: new Set([...context.bindings, bindingId]),
|
|
});
|