java-topology/defects/ppsspp/test/PpssppKernelDedup.java

import java.util.*;

/**
 * Unit tests for PPSSPP CWE-407 defects.
 *
 * ppsspp-0001: sceKernelThread waitingThreads vector dedup O(W^2)
 * ppsspp-0002: sceKernelSemaphore waitingThreads vector dedup O(W^2)
 * ppsspp-0003: IRJit byPage_ block removal O(P*B)
 */
public class PpssppKernelDedup {

    // --- ppsspp-0001/0002: waitingThreads dedup ---

    /** DEFECTIVE: linear scan before push_back */
    static void addWaiter_defective(List<Integer> waiters, int threadId) {
        if (!waiters.contains(threadId)) {
            waiters.add(threadId);
        }
    }

    /** FIXED: hash set for O(1) dedup */
    static void addWaiter_fixed(List<Integer> waiters, Set<Integer> waiterSet, int threadId) {
        if (waiterSet.add(threadId)) {
            waiters.add(threadId);
        }
    }

    // --- ppsspp-0003: byPage block removal ---

    /** DEFECTIVE: linear scan for removal */
    static boolean removeBlock_defective(List<Integer> pageBlocks, int blockIndex) {
        int idx = pageBlocks.indexOf(blockIndex);
        if (idx >= 0) {
            pageBlocks.remove(idx);
            return true;
        }
        return false;
    }

    /** FIXED: set-based removal */
    static boolean removeBlock_fixed(Set<Integer> pageBlockSet, int blockIndex) {
        return pageBlockSet.remove(blockIndex);
    }

    public static void main(String[] args) {
        int passed = 0;
        int failed = 0;

        // --- Test 1: ppsspp-0001 correctness ---
        {
            List<Integer> defect = new ArrayList<>();
            List<Integer> fixed = new ArrayList<>();
            Set<Integer> fixedSet = new HashSet<>();
            for (int i = 0; i < 50; i++) {
                addWaiter_defective(defect, i);
                addWaiter_defective(defect, i); // dup from tight-loop timeout
                addWaiter_fixed(fixed, fixedSet, i);
                addWaiter_fixed(fixed, fixedSet, i);
            }
            boolean ok = defect.size() == 50 && fixed.size() == 50;
            System.out.println((ok ? "PASS" : "FAIL") + " ppsspp-0001 correctness: thread waiter dedup");
            if (ok) passed++; else failed++;
        }

        // --- Test 2: ppsspp-0001 performance ---
        {
            int N = 5000;
            List<Integer> defect = new ArrayList<>();
            long t0 = System.nanoTime();
            for (int i = 0; i < N; i++) addWaiter_defective(defect, i);
            long defectNs = System.nanoTime() - t0;

            List<Integer> fixed = new ArrayList<>();
            Set<Integer> fixedSet = new HashSet<>();
            t0 = System.nanoTime();
            for (int i = 0; i < N; i++) addWaiter_fixed(fixed, fixedSet, i);
            long fixedNs = System.nanoTime() - t0;

            double ratio = (double) defectNs / Math.max(fixedNs, 1);
            boolean ok = ratio > 5.0;
            System.out.printf("%s ppsspp-0001 performance: N=%d defect=%.1fms fixed=%.1fms ratio=%.1fx%n",
                    ok ? "PASS" : "FAIL", N, defectNs / 1e6, fixedNs / 1e6, ratio);
            if (ok) passed++; else failed++;
        }

        // --- Test 3: ppsspp-0002 correctness (same pattern, sema context) ---
        {
            List<Integer> defect = new ArrayList<>();
            List<Integer> fixed = new ArrayList<>();
            Set<Integer> fixedSet = new HashSet<>();
            // Simulate tight-loop timeout adding same threads repeatedly
            for (int round = 0; round < 10; round++) {
                for (int tid = 0; tid < 20; tid++) {
                    addWaiter_defective(defect, tid);
                    addWaiter_fixed(fixed, fixedSet, tid);
                }
            }
            boolean ok = defect.size() == 20 && fixed.size() == 20;
            System.out.println((ok ? "PASS" : "FAIL") + " ppsspp-0002 correctness: sema waiter dedup");
            if (ok) passed++; else failed++;
        }

        // --- Test 4: ppsspp-0002 performance (many unique waiters) ---
        {
            int N = 5000;
            List<Integer> defect = new ArrayList<>();
            long t0 = System.nanoTime();
            for (int tid = 0; tid < N; tid++) {
                addWaiter_defective(defect, tid);
            }
            long defectNs = System.nanoTime() - t0;

            List<Integer> fixed = new ArrayList<>();
            Set<Integer> fixedSet = new HashSet<>();
            t0 = System.nanoTime();
            for (int tid = 0; tid < N; tid++) {
                addWaiter_fixed(fixed, fixedSet, tid);
            }
            long fixedNs = System.nanoTime() - t0;

            double ratio = (double) defectNs / Math.max(fixedNs, 1);
            boolean ok = ratio > 5.0;
            System.out.printf("%s ppsspp-0002 performance: N=%d defect=%.1fms fixed=%.1fms ratio=%.1fx%n",
                    ok ? "PASS" : "FAIL", N, defectNs / 1e6, fixedNs / 1e6, ratio);
            if (ok) passed++; else failed++;
        }

        // --- Test 5: ppsspp-0003 correctness ---
        {
            List<Integer> defectPage = new ArrayList<>();
            Set<Integer> fixedPage = new HashSet<>();
            for (int i = 0; i < 100; i++) {
                defectPage.add(i);
                fixedPage.add(i);
            }
            boolean d = removeBlock_defective(defectPage, 50);
            boolean f = removeBlock_fixed(fixedPage, 50);
            boolean ok = d && f && defectPage.size() == 99 && fixedPage.size() == 99;
            System.out.println((ok ? "PASS" : "FAIL") + " ppsspp-0003 correctness: byPage block removal");
            if (ok) passed++; else failed++;
        }

        // --- Test 6: ppsspp-0003 performance ---
        {
            int N = 5000;
            List<Integer> defectPage = new ArrayList<>();
            Set<Integer> fixedPage = new HashSet<>();
            for (int i = 0; i < N; i++) {
                defectPage.add(i);
                fixedPage.add(i);
            }

            long t0 = System.nanoTime();
            for (int i = N - 1; i >= 0; i--) {
                removeBlock_defective(defectPage, i);
            }
            long defectNs = System.nanoTime() - t0;

            t0 = System.nanoTime();
            for (int i = N - 1; i >= 0; i--) {
                removeBlock_fixed(fixedPage, i);
            }
            long fixedNs = System.nanoTime() - t0;

            double ratio = (double) defectNs / Math.max(fixedNs, 1);
            boolean ok = ratio > 5.0;
            System.out.printf("%s ppsspp-0003 performance: N=%d defect=%.1fms fixed=%.1fms ratio=%.1fx%n",
                    ok ? "PASS" : "FAIL", N, defectNs / 1e6, fixedNs / 1e6, ratio);
            if (ok) passed++; else failed++;
        }

        System.out.printf("%n%d/%d tests passed%n", passed, passed + failed);
        if (failed > 0) System.exit(1);
    }
}