java-topology/defects/swift/unit/SwiftTest.java

import java.util.*;

/**
 * CWE-407 simulation: Swift LoadableByAddress pass linear membership tests.
 *
 * The StructLoweringState in LoadableByAddress.cpp uses SmallVector with
 * std::find for membership tests on largeLoadableArgs, applies, and other
 * instruction vectors. For each instruction in the function, std::find
 * performs O(A) linear scan where A = number of large loadable args.
 *
 * Defect: O(I x A) where I = instructions, A = large loadable args
 * Fix: SmallPtrSet shadow for O(1) membership tests -> O(I + A)
 *
 * swift-0001: LoadableByAddress largeLoadableArgs/applies linear membership
 */
public class SwiftTest {

    // --- Defective: SmallVector + std::find pattern ---
    static long visitApplyDefective(List<Object> largeLoadableArgs,
                                     List<Object> funcSigArgs,
                                     List<Object> applies,
                                     List<Object[]> applyOperands) {
        long ops = 0;
        for (Object[] operands : applyOperands) {
            for (Object operand : operands) {
                ops++;
                // std::find(largeLoadableArgs.begin(), ..., currOperand)
                boolean found = false;
                for (Object arg : largeLoadableArgs) {
                    ops++;
                    if (arg == operand) { found = true; break; }
                }
                if (!found) {
                    // std::find(funcSigArgs.begin(), ..., currOperand)
                    for (Object arg : funcSigArgs) {
                        ops++;
                        if (arg == operand) { found = true; break; }
                    }
                }
                if (found) {
                    // Dedup check: std::find(applies.begin(), ..., instr)
                    Object instr = operands; // proxy for instruction
                    for (Object a : applies) {
                        ops++;
                        if (a == instr) { found = false; break; }
                    }
                    if (found) applies.add(instr);
                }
            }
        }
        return ops;
    }

    // --- Fixed: SmallPtrSet shadow for O(1) lookup ---
    static long visitApplyFixed(Set<Object> largeLoadableArgsSet,
                                 Set<Object> funcSigArgsSet,
                                 Set<Object> appliesSet,
                                 List<Object[]> applyOperands) {
        long ops = 0;
        for (Object[] operands : applyOperands) {
            for (Object operand : operands) {
                ops++;
                boolean found = largeLoadableArgsSet.contains(operand);
                ops++;
                if (!found) {
                    found = funcSigArgsSet.contains(operand);
                    ops++;
                }
                if (found) {
                    Object instr = operands;
                    if (appliesSet.add(instr)) {
                        ops++;
                    }
                }
            }
        }
        return ops;
    }

    public static void main(String[] args) {
        // Simulate a function with A large loadable args and I apply instructions
        int[] sizes = {10, 50, 100, 200, 500};

        System.out.println("swift-0001: LoadableByAddress largeLoadableArgs linear membership");
        System.out.println("=================================================================");
        System.out.printf("%-8s %-14s %-14s %-10s %-6s%n",
                "A(args)", "Defective ops", "Fixed ops", "Ratio", "Status");

        boolean allPass = true;
        for (int A : sizes) {
            // Create A large loadable args
            List<Object> largeLoadableArgs = new ArrayList<>();
            Set<Object> largeLoadableArgsSet = new HashSet<>();
            List<Object> funcSigArgs = new ArrayList<>();
            Set<Object> funcSigArgsSet = new HashSet<>();
            List<Object> applies = new ArrayList<>();
            Set<Object> appliesSet = new HashSet<>();

            Object[] argPool = new Object[A];
            for (int i = 0; i < A; i++) {
                argPool[i] = new Object();
                largeLoadableArgs.add(argPool[i]);
                largeLoadableArgsSet.add(argPool[i]);
                funcSigArgs.add(argPool[i]);
                funcSigArgsSet.add(argPool[i]);
            }

            // Create I apply instructions, each with 3 operands from the arg pool
            int I = A * 2;  // instructions proportional to args
            List<Object[]> applyOperands = new ArrayList<>();
            Random rng = new Random(42);
            for (int i = 0; i < I; i++) {
                Object[] ops = new Object[3];
                for (int j = 0; j < 3; j++) {
                    ops[j] = argPool[rng.nextInt(A)];
                }
                applyOperands.add(ops);
            }

            long defectOps = visitApplyDefective(
                    new ArrayList<>(largeLoadableArgs),
                    new ArrayList<>(funcSigArgs),
                    new ArrayList<>(applies),
                    applyOperands);
            long fixedOps = visitApplyFixed(
                    new HashSet<>(largeLoadableArgsSet),
                    new HashSet<>(funcSigArgsSet),
                    new HashSet<>(appliesSet),
                    applyOperands);

            double ratio = (double) defectOps / fixedOps;
            boolean pass = ratio > 2.0;
            allPass &= pass;

            System.out.printf("%-8d %-14d %-14d %-10.1f %-6s%n",
                    A, defectOps, fixedOps, ratio, pass ? "PASS" : "FAIL");
        }

        System.out.println();
        System.out.println(allPass ? "ALL PASS" : "SOME FAIL");
        System.exit(allPass ? 0 : 1);
    }
}