GC 빠른 레퍼런스

GC Quick Reference

Enable GC Mode

# Enable GC with default settings
vaisc build myprogram.vais --gc

# Enable GC with custom threshold (2MB)
vaisc build myprogram.vais --gc --gc-threshold 2097152

Import GC Module

U std/gc

Initialize GC

F main() -> i64 {
    gc_init()  # Call once at program start
    # ...
}

Allocate Memory

# Allocate 1024 bytes with type_id 0
ptr := gc_alloc(1024, 0)

# Allocate with simple API
ptr := gc_alloc_simple(1024)

Root Management

# Register a root (prevents collection)
gc_add_root(ptr)

# Unregister a root (allows collection)
gc_remove_root(ptr)

Trigger Collection

# Force garbage collection
gc_collect()

Configuration

# Set threshold to 4KB
gc_set_threshold(4096)

Statistics

# Get current allocated bytes
bytes := gc_bytes_allocated()

# Get number of live objects
count := gc_objects_count()

# Get collection count
collections := gc_collections()

# Print all statistics
gc_print_stats()

# Get stats as struct
stats := gc_stats()
printf("Allocated: %ld bytes\n", stats.bytes_allocated)

Complete Example

U std/gc

F main() -> i64 {
    # Initialize
    gc_init()
    gc_set_threshold(1048576)  # 1MB

    # Allocate
    i := 0
    L i < 10 {
        ptr := gc_alloc(1024, 0)
        # Use ptr...
        i = i + 1
    }

    # Check stats
    printf("Allocated: %ld bytes\n", gc_bytes_allocated())
    printf("Objects: %ld\n", gc_objects_count())

    # Force collection
    gc_collect()

    # Final stats
    gc_print_stats()

    0
}

GC-Managed Vector Example

S GcVec {
    data: i64,  # GC-managed pointer
    len: i64,
    cap: i64
}

X GcVec {
    F new() -> GcVec {
        data_ptr := gc_alloc(32, 100)
        gc_add_root(data_ptr)  # Prevent collection
        GcVec { data: data_ptr, len: 0, cap: 4 }
    }

    F drop(&self) -> i64 {
        gc_remove_root(self.data)  # Allow collection
        0
    }
}

Default Settings

• Threshold: 1 MB (1048576 bytes)
• Algorithm: Mark-and-Sweep
• Scanning: Conservative

API Summary

Troubleshooting

Memory keeps growing

• Lower the threshold: gc_set_threshold(smaller_value)
• Force collection manually: gc_collect()
• Check for memory leaks (rooted objects)

Objects collected too early

• Register as root: gc_add_root(ptr)
• Keep references on stack
• Check scope lifetime

Slow performance

• Increase threshold: gc_set_threshold(larger_value)
• Reduce allocation frequency
• Consider manual memory management for hot paths

See Also

• /crates/vais-gc/README.md - Detailed GC documentation
• /docs/gc-implementation.md - Implementation details
• /examples/gc_test.vais - Comprehensive tests
• /examples/gc_vec_test.vais - Vector example