import type { AssignStmt, Expr, Stmt } from "./ast"
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type Operand = string | number
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type ASSA<Data> = { dest: string, source: Operand } & Data
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export type SSACopy = ASSA<{ source: Operand }> // dest = source
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export type SSAUnary = ASSA<{ op: string }> // dest = op(source)
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export type SSABinary = ASSA<{ op: string, source1: Operand }> // dest = op(source, source1)
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export type SSA = SSACopy | SSAUnary | SSABinary
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type IRState = {
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nextID: number
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ssa_stmts: Array<SSA>
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}
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export const convertIR = (stmts: Array<Stmt>): Array<SSA> => {
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const state: IRState = {
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nextID: 0,
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ssa_stmts: [],
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}
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stmts.forEach(stmt => {
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const ssa_stmts = convertAssignStmt(state, stmt)
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state.ssa_stmts.push(...ssa_stmts)
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})
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return state.ssa_stmts
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}
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export const convertAssignStmt = (state: IRState, stmt: AssignStmt): Array<SSA> => {
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const dest = stmt.args.name
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const [source, expr_stmts] = convertExpr(state, stmt.args.expr)
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expr_stmts.push({
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dest,
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source,
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})
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return expr_stmts
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}
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export const convertExpr = (state: IRState, expr: Expr): [string | number, Array<SSA>] => {
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if (typeof expr === "number" || typeof expr === "string") {
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return [expr, []]
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} else if (expr.type === "unary") {
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const [source, expr_stmts] = convertExpr(state, expr.arg)
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const name = `temp${state.nextID++}`
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expr_stmts.push({
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dest: name,
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source,
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op: expr.op,
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})
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return [name, expr_stmts]
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} else {
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const [left_source, left_stmts] = convertExpr(state, expr.left)
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const [right_source, right_stmts] = convertExpr(state, expr.right)
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const expr_stmts = [...left_stmts, ...right_stmts]
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const name = `temp${state.nextID++}`
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expr_stmts.push({
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dest: name,
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op: expr.op,
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source: left_source,
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source1: right_source,
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})
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return [name, expr_stmts]
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}
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}
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export const prettyPrintIR = (ssa: SSA): string => {
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let output = ""
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if ("source1" in ssa) {
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output = `${ssa.dest} = ${ssa.source} ${ssa.op} ${ssa.source1}`
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} else if ("op" in ssa) {
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output = `${ssa.dest} = ${ssa.op} ${ssa.source}`
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} else {
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output = `${ssa.dest} = ${ssa.source}`
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}
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return output
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}
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