hakmem/tests/test_tls_ss_hint.c

// test_tls_ss_hint.c - Unit tests for TLS SuperSlab Hint Box
//
// Purpose: Validate TLS hint cache behavior (init, update, lookup, FIFO rotation)
// Build: gcc -o test_tls_ss_hint test_tls_ss_hint.c -I../core -DHAKMEM_TINY_SS_TLS_HINT=1
// Run: ./test_tls_ss_hint

#include <stdio.h>
#include <assert.h>
#include <stdint.h>
#include <string.h>

// Define build flags for test compilation
#ifndef HAKMEM_BUILD_RELEASE
#define HAKMEM_BUILD_RELEASE 0
#endif

#ifndef HAKMEM_TINY_SS_TLS_HINT
#define HAKMEM_TINY_SS_TLS_HINT 1
#endif

// Include the hint box header
#include "box/tls_ss_hint_box.h"

// Mock SuperSlab for testing
#define SUPERSLAB_MAGIC 0x5353504C  // 'SSPL'

typedef struct SuperSlab {
    uint32_t magic;
    uint8_t  lg_size;
    uint8_t  _pad[3];
} SuperSlab;

// Define the TLS variable (normally in hakmem_tiny_tls_state_box.inc)
__thread TlsSsHintCache g_tls_ss_hint = {0};

// ============================================================================
// Test Functions
// ============================================================================

void test_hint_init(void) {
    printf("test_hint_init...\n");

    tls_ss_hint_init();

    // Verify cache is empty
    assert(g_tls_ss_hint.count == 0);
    assert(g_tls_ss_hint.next_slot == 0);

    #if !HAKMEM_BUILD_RELEASE
    assert(g_tls_ss_hint.hits == 0);
    assert(g_tls_ss_hint.misses == 0);
    #endif

    printf("  PASS\n");
}

void test_hint_basic(void) {
    printf("test_hint_basic...\n");

    tls_ss_hint_init();

    // Mock SuperSlab
    SuperSlab ss = {
        .magic = SUPERSLAB_MAGIC,
        .lg_size = 21,  // 2MB
    };
    void* ss_base = (void*)0x1000000;
    size_t ss_size = 2 * 1024 * 1024;  // 2MB

    // Update hint
    tls_ss_hint_update(&ss, ss_base, ss_size);

    // Verify cache entry
    assert(g_tls_ss_hint.count == 1);
    assert(g_tls_ss_hint.entries[0].base == ss_base);
    assert(g_tls_ss_hint.entries[0].ss == &ss);

    // Lookup should hit (within range)
    SuperSlab* out = NULL;
    assert(tls_ss_hint_lookup((void*)0x1000100, &out) == true);
    assert(out == &ss);

    // Lookup at base should hit
    assert(tls_ss_hint_lookup((void*)0x1000000, &out) == true);
    assert(out == &ss);

    // Lookup at end-1 should hit
    assert(tls_ss_hint_lookup((void*)0x11FFFFF, &out) == true);
    assert(out == &ss);

    // Lookup at end should miss (exclusive boundary)
    assert(tls_ss_hint_lookup((void*)0x1200000, &out) == false);

    // Lookup outside range should miss
    assert(tls_ss_hint_lookup((void*)0x3000000, &out) == false);

    printf("  PASS\n");
}

void test_hint_fifo_rotation(void) {
    printf("test_hint_fifo_rotation...\n");

    tls_ss_hint_init();

    // Create 6 mock SuperSlabs (cache has 4 slots)
    SuperSlab ss[6];
    for (int i = 0; i < 6; i++) {
        ss[i].magic = SUPERSLAB_MAGIC;
        ss[i].lg_size = 21;  // 2MB
        void* base = (void*)(uintptr_t)(0x1000000 + i * 0x200000);  // 2MB apart
        size_t size = 2 * 1024 * 1024;

        tls_ss_hint_update(&ss[i], base, size);
    }

    // Cache should be full (4 slots)
    assert(g_tls_ss_hint.count == TLS_SS_HINT_SLOTS);

    // First 2 SuperSlabs should be evicted (FIFO)
    SuperSlab* out = NULL;
    assert(tls_ss_hint_lookup((void*)0x1000100, &out) == false);  // ss[0] evicted
    assert(tls_ss_hint_lookup((void*)0x1200100, &out) == false);  // ss[1] evicted

    // Last 4 SuperSlabs should be cached
    assert(tls_ss_hint_lookup((void*)0x1400100, &out) == true);   // ss[2]
    assert(out == &ss[2]);
    assert(tls_ss_hint_lookup((void*)0x1600100, &out) == true);   // ss[3]
    assert(out == &ss[3]);
    assert(tls_ss_hint_lookup((void*)0x1800100, &out) == true);   // ss[4]
    assert(out == &ss[4]);
    assert(tls_ss_hint_lookup((void*)0x1A00100, &out) == true);   // ss[5]
    assert(out == &ss[5]);

    printf("  PASS\n");
}

void test_hint_duplicate_detection(void) {
    printf("test_hint_duplicate_detection...\n");

    tls_ss_hint_init();

    // Mock SuperSlab
    SuperSlab ss = {
        .magic = SUPERSLAB_MAGIC,
        .lg_size = 21,  // 2MB
    };
    void* ss_base = (void*)0x1000000;
    size_t ss_size = 2 * 1024 * 1024;

    // Update hint 3 times with same SuperSlab
    tls_ss_hint_update(&ss, ss_base, ss_size);
    tls_ss_hint_update(&ss, ss_base, ss_size);
    tls_ss_hint_update(&ss, ss_base, ss_size);

    // Cache should have only 1 entry (duplicates ignored)
    assert(g_tls_ss_hint.count == 1);
    assert(g_tls_ss_hint.entries[0].ss == &ss);

    printf("  PASS\n");
}

void test_hint_clear(void) {
    printf("test_hint_clear...\n");

    tls_ss_hint_init();

    // Add some entries
    SuperSlab ss = {
        .magic = SUPERSLAB_MAGIC,
        .lg_size = 21,  // 2MB
    };
    void* ss_base = (void*)0x1000000;
    size_t ss_size = 2 * 1024 * 1024;

    tls_ss_hint_update(&ss, ss_base, ss_size);

    assert(g_tls_ss_hint.count == 1);

    // Clear cache
    tls_ss_hint_clear();

    // Cache should be empty
    assert(g_tls_ss_hint.count == 0);
    assert(g_tls_ss_hint.next_slot == 0);

    // Lookup should miss
    SuperSlab* out = NULL;
    assert(tls_ss_hint_lookup((void*)0x1000100, &out) == false);

    printf("  PASS\n");
}

#if !HAKMEM_BUILD_RELEASE
void test_hint_stats(void) {
    printf("test_hint_stats...\n");

    tls_ss_hint_init();

    // Add entry
    SuperSlab ss = {
        .magic = SUPERSLAB_MAGIC,
        .lg_size = 21,  // 2MB
    };
    void* ss_base = (void*)0x1000000;
    size_t ss_size = 2 * 1024 * 1024;

    tls_ss_hint_update(&ss, ss_base, ss_size);

    // Perform lookups
    SuperSlab* out = NULL;
    tls_ss_hint_lookup((void*)0x1000100, &out);  // Hit
    tls_ss_hint_lookup((void*)0x1000200, &out);  // Hit
    tls_ss_hint_lookup((void*)0x3000000, &out);  // Miss

    // Check stats
    uint64_t hits = 0, misses = 0;
    tls_ss_hint_stats(&hits, &misses);

    assert(hits == 2);
    assert(misses == 1);

    printf("  PASS\n");
}
#endif

// ============================================================================
// Main Test Runner
// ============================================================================

int main(void) {
    printf("===========================================\n");
    printf("TLS SuperSlab Hint Box - Unit Tests\n");
    printf("===========================================\n\n");

    test_hint_init();
    test_hint_basic();
    test_hint_fifo_rotation();
    test_hint_duplicate_detection();
    test_hint_clear();

    #if !HAKMEM_BUILD_RELEASE
    test_hint_stats();
    #endif

    printf("\n===========================================\n");
    printf("All tests PASSED!\n");
    printf("===========================================\n");

    return 0;
}