hakmem/core/box/tiny_route_env_box.h

// tiny_route_env_box.h - Route snapshot for Tiny front (Heap vs Legacy)
// 役割:
//   - 起動時に「各クラスが TinyHeap を使うか」をスナップショットし、ホットパスでは LUT 1 回に縮約する。
//   - HAKMEM_TINY_HEAP_PROFILE / HAKMEM_TINY_HEAP_BOX / HAKMEM_TINY_HEAP_CLASSES の組合せをここで解決する。
#pragma once

#include <stdint.h>
#include <stdlib.h>
#include "../hakmem_tiny_config.h"
#include "tiny_heap_env_box.h"
#include "free_dispatch_stats_box.h"  // Phase FREE-DISPATCHER-OPT-1

#include "smallobject_hotbox_v3_env_box.h"
#include "smallobject_hotbox_v4_env_box.h"
#include "smallobject_v5_env_box.h"

// ENV sentinel values
#ifndef ENV_UNINIT
#define ENV_UNINIT   (-1)
#define ENV_ENABLED  (1)
#define ENV_DISABLED (0)
#endif

typedef enum {
    TINY_ROUTE_LEGACY = 0,
    TINY_ROUTE_HEAP = 1,             // TinyHeap v1
    TINY_ROUTE_HOTHEAP_V2 = 2,       // TinyHotHeap v2
    TINY_ROUTE_SMALL_HEAP_V3 = 3,    // SmallObject HotHeap v3 (C7-first,研究箱)
    TINY_ROUTE_SMALL_HEAP_V4 = 4,    // SmallObject HotHeap v4 (stub, route未使用)
    TINY_ROUTE_SMALL_HEAP_V5 = 5,    // SmallObject HotHeap v5 (C6-only route stub, Phase v5-1)
    TINY_ROUTE_SMALL_HEAP_V6 = 6,    // SmallObject Core v6 (C6-only route stub, Phase v6-1)
} tiny_route_kind_t;

extern tiny_route_kind_t g_tiny_route_class[TINY_NUM_CLASSES];
extern int g_tiny_route_snapshot_done;

// ============================================================================
// Phase v6-1: SmallObject Core v6 ENV gate (must be before tiny_route_snapshot_init)
// ============================================================================

// small_heap_v6_enabled() - グローバル v6 enable check
static inline int small_heap_v6_enabled(void) {
    static int g_enabled = ENV_UNINIT;
    if (__builtin_expect(g_enabled == ENV_UNINIT, 0)) {
        const char* e = getenv("HAKMEM_SMALL_HEAP_V6_ENABLED");
        g_enabled = (e && *e && *e != '0') ? ENV_ENABLED : ENV_DISABLED;
    }
    return (g_enabled == ENV_ENABLED);
}

// small_heap_v6_class_mask() - v6 対象クラスのビットマスク
static inline uint32_t small_heap_v6_class_mask(void) {
    static int g_mask = ENV_UNINIT;
    if (__builtin_expect(g_mask == ENV_UNINIT, 0)) {
        const char* e = getenv("HAKMEM_SMALL_HEAP_V6_CLASSES");
        if (e && *e) {
            g_mask = (int)strtoul(e, NULL, 0);
        } else {
            g_mask = 0x0;  // default: OFF
        }
    }
    return (uint32_t)g_mask;
}

// small_heap_v6_class_enabled() - 指定クラスが v6 有効か
static inline int small_heap_v6_class_enabled(uint32_t class_idx) {
    if (class_idx >= 8) return 0;
    if (!small_heap_v6_enabled()) return 0;
    uint32_t mask = small_heap_v6_class_mask();
    return (mask & (1u << class_idx)) ? 1 : 0;
}

static inline void tiny_route_snapshot_init(void) {
    for (int i = 0; i < TINY_NUM_CLASSES; i++) {
        // Phase v6-1: C6-only v6 route stub (highest priority)
        FREE_DISPATCH_STAT_INC(env_checks);  // ENV check counter
        if (small_heap_v6_class_enabled((uint32_t)i)) {
            g_tiny_route_class[i] = TINY_ROUTE_SMALL_HEAP_V6;
            FREE_DISPATCH_STAT_INC(route_core_v6);
        } else if (i == 6 && small_heap_v5_class_enabled(6)) {
            // Phase v5-1: C6-only v5 route stub (before v4 check)
            FREE_DISPATCH_STAT_INC(env_checks);
            g_tiny_route_class[i] = TINY_ROUTE_SMALL_HEAP_V5;
        } else if (small_heap_v4_class_enabled((uint8_t)i)) {
            FREE_DISPATCH_STAT_INC(env_checks);
            g_tiny_route_class[i] = TINY_ROUTE_SMALL_HEAP_V4;
        } else if (small_heap_v3_class_enabled((uint8_t)i)) {
            FREE_DISPATCH_STAT_INC(env_checks);
            g_tiny_route_class[i] = TINY_ROUTE_SMALL_HEAP_V3;
        } else if (tiny_hotheap_v2_class_enabled((uint8_t)i)) {
            FREE_DISPATCH_STAT_INC(env_checks);
            g_tiny_route_class[i] = TINY_ROUTE_HOTHEAP_V2;
        } else if (tiny_heap_box_enabled() && tiny_heap_class_route_enabled(i)) {
            FREE_DISPATCH_STAT_INC(env_checks);
            FREE_DISPATCH_STAT_INC(env_checks);
            g_tiny_route_class[i] = TINY_ROUTE_HEAP;
        } else {
            g_tiny_route_class[i] = TINY_ROUTE_LEGACY;
            FREE_DISPATCH_STAT_INC(route_tiny_legacy);
        }
    }
    g_tiny_route_snapshot_done = 1;
}

static inline tiny_route_kind_t tiny_route_for_class(uint8_t ci) {
    FREE_DISPATCH_STAT_INC(route_for_class_calls);  // Phase FREE-DISPATCHER-OPT-1
    if (__builtin_expect(!g_tiny_route_snapshot_done, 0)) {
        tiny_route_snapshot_init();
    }
    if (__builtin_expect(ci >= TINY_NUM_CLASSES, 0)) {
        return TINY_ROUTE_LEGACY;
    }
    return g_tiny_route_class[ci];
}

static inline int tiny_route_is_heap_kind(tiny_route_kind_t route) {
    return route == TINY_ROUTE_HEAP ||
           route == TINY_ROUTE_HOTHEAP_V2 ||
           route == TINY_ROUTE_SMALL_HEAP_V3 ||
           route == TINY_ROUTE_SMALL_HEAP_V4 ||
           route == TINY_ROUTE_SMALL_HEAP_V5 ||
           route == TINY_ROUTE_SMALL_HEAP_V6;
}

// C7 front が TinyHeap を使うか（Route snapshot 経由で判定）
static inline int tiny_c7_front_uses_heap(void) {
    return tiny_route_is_heap_kind(tiny_route_for_class(7));
}

// C6 front が TinyHeap を使うか（Route snapshot 経由で判定）
static inline int tiny_c6_front_uses_heap(void) {
    return tiny_route_is_heap_kind(tiny_route_for_class(6));
}