windjammer 0.48.0

//! V8-specific optimizations
//!
//! Applies optimizations that target V8's (Chrome/Node.js) JavaScript engine
//! for better performance.

/// V8 optimization hints and patterns
pub struct V8Optimizer;

impl V8Optimizer {
    /// Create a new V8 optimizer
    pub fn new() -> Self {
        Self
    }

    /// Optimize code for V8
    pub fn optimize(&self, code: &str) -> String {
        let mut optimized = code.to_string();

        // Apply various V8-specific optimizations
        optimized = self.optimize_object_shapes(&optimized);
        optimized = self.optimize_function_calls(&optimized);
        optimized = self.optimize_loops(&optimized);
        optimized = self.add_type_hints(&optimized);

        optimized
    }

    /// Optimize object shapes (hidden classes in V8)
    fn optimize_object_shapes(&self, code: &str) -> String {
        // V8 optimizes objects with consistent property order
        // Ensure constructor assigns properties in same order

        code.to_string()
    }

    /// Optimize function calls
    fn optimize_function_calls(&self, code: &str) -> String {
        // Monomorphic calls are faster in V8
        // Avoid polymorphic call sites

        code.to_string()
    }

    /// Optimize loops
    fn optimize_loops(&self, code: &str) -> String {
        // V8's TurboFan can optimize tight loops
        // Ensure loop bodies are small and predictable

        code.to_string()
    }

    /// Add type hints for V8
    fn add_type_hints(&self, code: &str) -> String {
        // V8 can optimize better with type feedback
        // Add JSDoc type annotations

        code.to_string()
    }

    /// Generate V8-specific optimization hints as comments
    pub fn generate_optimization_hints() -> String {
        r#"// V8 Optimization Hints
// 1. Monomorphic functions: Call sites with single type are faster
// 2. Hidden classes: Objects with same property order share hidden classes
// 3. Inline caches: Consistent property access patterns enable ICs
// 4. TurboFan: Small, hot functions get optimized by TurboFan compiler
// 5. Array operations: Use typed arrays for numeric operations
// 6. Avoid try-catch in hot paths: Prevents optimization

"#
        .to_string()
    }
}

impl Default for V8Optimizer {
    fn default() -> Self {
        Self::new()
    }
}

/// V8 optimization patterns and best practices
pub mod patterns {
    /// Generate optimized array iteration
    pub fn optimized_array_loop(array_name: &str, body: &str) -> String {
        format!(
            r#"// Optimized for V8 TurboFan
const {array}_length = {array}.length;
for (let i = 0; i < {array}_length; i++) {{
    const item = {array}[i];
    {body}
}}"#,
            array = array_name,
            body = body
        )
    }

    /// Generate optimized object creation
    pub fn optimized_object_creation(class_name: &str, fields: &[(&str, &str)]) -> String {
        let mut code = format!("class {} {{\n", class_name);
        code.push_str("    constructor(");

        let params: Vec<String> = fields.iter().map(|(name, _)| (*name).to_string()).collect();
        code.push_str(&params.join(", "));
        code.push_str(") {\n");

        // Initialize fields in consistent order for hidden class optimization
        for (name, _) in fields {
            code.push_str(&format!("        this.{} = {};\n", name, name));
        }

        code.push_str("    }\n");
        code.push_str("}\n");

        code
    }

    /// Generate optimized number operations
    pub fn optimized_number_ops() -> String {
        r#"// V8 optimized number operations
// Use |0 for integer conversion (SMI optimization)
function toInt32(x) {
    return x | 0;
}

// Use Math.imul for integer multiplication
function multiplyInt32(a, b) {
    return Math.imul(a | 0, b | 0);
}

// Use typed arrays for numeric operations
function createOptimizedArray(size) {
    return new Float64Array(size); // or Int32Array for integers
}
"#
        .to_string()
    }

    /// Generate optimized function patterns
    pub fn optimized_function_pattern() -> String {
        r#"// V8 optimized function patterns
// 1. Keep functions small (< 600 bytes for inlining)
// 2. Avoid changing function signatures
// 3. Use consistent types for parameters
// 4. Avoid arguments object, use rest parameters

// Good: Monomorphic function
function add(a, b) {
    return a + b;  // Always called with numbers
}

// Good: Small, inlineable function
function square(x) {
    return x * x;
}

// Avoid: Try-catch in hot path
// Bad:
function processFast(x) {
    try {
        return compute(x);
    } catch (e) {
        return 0;
    }
}

// Better: Check before calling
function processFast(x) {
    if (!isValid(x)) return 0;
    return compute(x);
}
"#
        .to_string()
    }
}

/// V8 runtime optimizations
pub mod runtime {
    /// Generate V8 runtime optimization flags
    pub fn optimization_flags() -> String {
        r#"// V8 Runtime Optimization Flags
// These can be passed to Node.js or Chrome:
//
// --optimize-for-size: Optimize for code size
// --max-old-space-size=4096: Increase heap size
// --turbo: Enable TurboFan compiler (default in modern V8)
// --no-lazy: Compile all functions immediately
// --trace-opt: See what gets optimized
// --trace-deopt: See what gets deoptimized
//
// Example usage:
// node --turbo --trace-opt app.js
"#
        .to_string()
    }

    /// Generate V8 optimization checks
    pub fn optimization_checks() -> String {
        r#"// V8 Optimization Status Checks
// Use these in development to check optimization status

function checkOptimizationStatus(fn) {
    // Only works with --allow-natives-syntax flag
    if (typeof %GetOptimizationStatus === 'function') {
        const status = %GetOptimizationStatus(fn);
        console.log('Optimization status:', {
            optimized: (status & (1 << 0)) !== 0,
            alwaysOpt: (status & (1 << 1)) !== 0,
            neverOpt: (status & (1 << 2)) !== 0,
            maybeDeopted: (status & (1 << 3)) !== 0,
            turbofanned: (status & (1 << 4)) !== 0
        });
    } else {
        console.warn('Run with --allow-natives-syntax to check optimization status');
    }
}

// Example: Check if function is optimized
function hotFunction(x) {
    return x * x;
}

// Warm up
for (let i = 0; i < 10000; i++) hotFunction(i);

// Check status
checkOptimizationStatus(hotFunction);
"#
        .to_string()
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_v8_optimizer() {
        let optimizer = V8Optimizer::new();
        let code = "function test() { return 42; }";
        let optimized = optimizer.optimize(code);

        // Should return code (optimizations are no-ops for now)
        assert!(!optimized.is_empty());
    }

    #[test]
    fn test_optimization_hints() {
        let hints = V8Optimizer::generate_optimization_hints();
        assert!(hints.contains("V8"));
        assert!(hints.contains("Monomorphic"));
        assert!(hints.contains("TurboFan"));
    }

    #[test]
    fn test_optimized_array_loop() {
        let loop_code = patterns::optimized_array_loop("items", "console.log(item);");
        assert!(loop_code.contains("items_length"));
        assert!(loop_code.contains("TurboFan"));
    }

    #[test]
    fn test_optimized_object_creation() {
        let fields = vec![("x", "number"), ("y", "number")];
        let class_code = patterns::optimized_object_creation("Point", &fields);

        assert!(class_code.contains("class Point"));
        assert!(class_code.contains("this.x"));
        assert!(class_code.contains("this.y"));
    }

    #[test]
    fn test_optimized_number_ops() {
        let ops = patterns::optimized_number_ops();
        assert!(ops.contains("toInt32"));
        assert!(ops.contains("Math.imul"));
        assert!(ops.contains("Float64Array"));
    }
}