Function buildXRayProfileMap

base/base/coverage.cpp:139–178

static void buildXRayProfileMap() __attribute__((xray_never_instrument));
static void buildXRayProfileMap()
{
    std::call_once(g_xray_map_once, []
    {
        const int32_t max_id = __xray_max_function_id();
        if (max_id <= 0) return;
        g_xray_max_id = max_id;

        /// Build NameRef → profile_data_index map first.
        const LLVMProfileData * begin = __llvm_profile_begin_data(); // NOLINT
        const LLVMProfileData * end   = __llvm_profile_end_data();   // NOLINT
        const uint32_t n = static_cast<uint32_t>(end - begin);
        std::unordered_map<uint64_t, uint32_t> name_hash_to_idx;
        name_hash_to_idx.reserve(n);
        for (uint32_t i = 0; i < n; ++i)
            name_hash_to_idx.emplace(begin[i].NameRef, i);

        /// Allocate depth array.
        g_xray_depth_size = n;
        g_xray_min_depth = new std::atomic<uint32_t>[n]; // NOLINT
        for (uint32_t i = 0; i < n; ++i)
            g_xray_min_depth[i].store(UINT32_MAX, std::memory_order_relaxed);

        /// For each XRay function_id, resolve to profile_data_index via symbol name hash.
        g_xray_to_profile = new uint32_t[static_cast<size_t>(max_id) + 1]; // NOLINT
        std::fill(g_xray_to_profile, g_xray_to_profile + max_id + 1, UINT32_MAX);

        for (int32_t id = 1; id <= max_id; ++id)
        {
            const void * addr = reinterpret_cast<const void *>(__xray_function_address(id));
            if (!addr) continue;
            Dl_info info;
            if (!dladdr(addr, &info) || !info.dli_sname) continue;
            const uint64_t h = fnv64(info.dli_sname);
            const auto it = name_hash_to_idx.find(h);
            if (it != name_hash_to_idx.end())
                g_xray_to_profile[id] = it->second;
        }
    });
}

static void xrayHandler(int32_t func_id, XRayEntryType type) __attribute__((xray_never_instrument));
static void xrayHandler(int32_t func_id, XRayEntryType type)