arena trace logging

arena_trace.c

typedef struct {
    // set to one of the TRACE_RECORD_*
    unsigned int trace_record_type;

    // number of bytes from the beginning of the page this allocation took place
    // took place
    unsigned int arena_page_offset;

    // the page the arena came from, count from 0
    unsigned int arena_page_number;

    // bytes in allocation
    size_t alloc_bytes;

    // if allocation orphans a pointer, such as when reallocing inside
    // of an arena, how many bytes were orphaned
    size_t orphaned_bytes;

    // address of now-orphaned memory
    void* orphaned_ptr;

    // stack addresses for the allocation
    void*        stack_addresses[TRACE_MAX_STACK_SIZE];
    unsigned int stack_address_count;

    // trailing bytes of padding after allocation before next allocation
    // (does not include jumping to the next page to fit an allocation)
    unsigned int padding_bytes;

    // the actual address of the allocation (or free, if trace_record_type is a free)
    const void* alloc_ptr;

    // pointer to the first arena in the chain
    const ftg_arena_t* arena_head;

    // number of elapsed nanoseconds since arena_trace_init called
    uint64_t elapsed_nanoseconds;

    // the frame number, or any step index that increases over time
    uint64_t frame_number;

    // name of the arena (ptr to arena_name_t record's name
    char arena_name[ARENA__MAX_STRLEN];
} arena_trace_record_t;