main.rs

//! Lambda VM CLI - execute, prove, and verify RISC-V programs.

use std::fs::File;
use std::io::{BufWriter, Write};
use std::path::PathBuf;
use std::process::ExitCode;
use std::time::Instant;

use clap::{Parser, Subcommand, ValueHint};

#[global_allocator]
static ALLOC: tikv_jemallocator::Jemalloc = tikv_jemallocator::Jemalloc;
use executor::{
    elf::{Elf, SymbolTable},
    flamegraph::FlamegraphGenerator,
    vm::execution::Executor,
};
use prover::VmProof;
use stark::proof::options::GoldilocksCubicProofOptions;

/// Polls jemalloc `stats.allocated` every 10ms from a background thread,
/// tracking the high-water mark. Near-zero overhead because jemalloc uses
/// thread-local caches — `epoch::advance()` just merges cached counters.
#[cfg(feature = "jemalloc-stats")]
mod heap_tracker {
    use std::sync::Arc;
    use std::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
    use std::thread;
    use std::time::Duration;

    use tikv_jemalloc_ctl::{epoch, stats};

    pub struct HeapTracker {
        stop: Arc<AtomicBool>,
        peak: Arc<AtomicUsize>,
        handle: Option<thread::JoinHandle<()>>,
    }

    impl HeapTracker {
        pub fn start() -> Self {
            let stop = Arc::new(AtomicBool::new(false));
            let peak = Arc::new(AtomicUsize::new(0));
            let stop_clone = stop.clone();
            let peak_clone = peak.clone();

            let handle = thread::spawn(move || {
                while !stop_clone.load(Ordering::Relaxed) {
                    // Refresh jemalloc's cached stats
                    epoch::advance().ok();
                    if let Ok(allocated) = stats::allocated::read() {
                        peak_clone.fetch_max(allocated, Ordering::Relaxed);
                    }
                    thread::sleep(Duration::from_millis(10));
                }
                // One final sample after stop signal
                epoch::advance().ok();
                if let Ok(allocated) = stats::allocated::read() {
                    peak_clone.fetch_max(allocated, Ordering::Relaxed);
                }
            });

            Self {
                stop,
                peak,
                handle: Some(handle),
            }
        }

        pub fn stop(mut self) -> usize {
            self.shutdown();
            self.peak.load(Ordering::Relaxed)
        }

        fn shutdown(&mut self) {
            self.stop.store(true, Ordering::Relaxed);
            if let Some(h) = self.handle.take() {
                h.join().ok();
            }
        }
    }

    impl Drop for HeapTracker {
        fn drop(&mut self) {
            self.shutdown();
        }
    }
}

#[derive(Parser)]
#[command(author, version, about = "Lambda VM - RISC-V zkVM", long_about = None)]
struct Cli {
    #[command(subcommand)]
    command: Commands,
}

#[derive(Subcommand)]
enum Commands {
    /// Execute an ELF program without generating a proof
    Execute {
        /// Path to the ELF file
        #[arg(value_parser, value_hint = ValueHint::FilePath)]
        elf: PathBuf,

        /// Generate flamegraph folded stacks to file
        #[arg(long, value_hint = ValueHint::FilePath)]
        flamegraph: Option<PathBuf>,
    },

    /// Generate a proof for an ELF program
    Prove {
        /// Path to the ELF file
        #[arg(value_parser, value_hint = ValueHint::FilePath)]
        elf: PathBuf,

        /// Output path for the proof bundle
        #[arg(short, long, value_hint = ValueHint::FilePath)]
        output: PathBuf,

        /// Blowup factor (power of 2). Higher = fewer queries, smaller proof, slower proving.
        #[arg(long)]
        blowup: Option<u8>,

        /// Print timing breakdown
        #[arg(long)]
        time: bool,
    },

    /// Verify a proof bundle
    Verify {
        /// Path to the proof bundle file
        #[arg(value_parser, value_hint = ValueHint::FilePath)]
        proof: PathBuf,

        /// Path to the ELF file (required for DECODE table verification)
        #[arg(value_parser, value_hint = ValueHint::FilePath)]
        elf: PathBuf,

        /// Blowup factor used during proving (must match)
        #[arg(long)]
        blowup: Option<u8>,

        /// Print timing breakdown
        #[arg(long)]
        time: bool,
    },
}

fn main() -> ExitCode {
    let cli = Cli::parse();

    match cli.command {
        Commands::Execute { elf, flamegraph } => cmd_execute(elf, flamegraph),
        Commands::Prove {
            elf,
            output,
            blowup,
            time,
        } => cmd_prove(elf, output, blowup, time),
        Commands::Verify {
            proof,
            elf,
            blowup,
            time,
        } => cmd_verify(proof, elf, blowup, time),
    }
}

fn cmd_execute(elf_path: PathBuf, flamegraph_path: Option<PathBuf>) -> ExitCode {
    let elf_data = match std::fs::read(&elf_path) {
        Ok(data) => data,
        Err(e) => {
            eprintln!("Failed to read ELF file: {}", e);
            return ExitCode::FAILURE;
        }
    };

    let program = match Elf::load(&elf_data) {
        Ok(p) => p,
        Err(e) => {
            eprintln!("Failed to load ELF program: {:?}", e);
            return ExitCode::FAILURE;
        }
    };

    let mut executor = match Executor::new(&program, vec![]) {
        Ok(e) => e,
        Err(e) => {
            eprintln!("Failed to create executor: {:?}", e);
            return ExitCode::FAILURE;
        }
    };

    // Set up flamegraph generator if requested
    let mut generator = flamegraph_path.as_ref().map(|_| {
        let symbols = SymbolTable::parse(&elf_data);
        FlamegraphGenerator::new(symbols, program.entry_point)
    });

    // Execute in chunks, processing logs only if generating flamegraph
    loop {
        let logs = match executor.resume() {
            Ok(logs) => logs,
            Err(e) => {
                eprintln!("Execution failed: {:?}", e);
                return ExitCode::FAILURE;
            }
        };
        match logs {
            Some(logs) => {
                if let Some(ref mut fg) = generator {
                    let logs: Vec<_> = logs.to_vec();
                    if let Err(e) = fg.process_logs(&logs, &executor.instructions) {
                        eprintln!("Failed to process logs for flamegraph: {:?}", e);
                        return ExitCode::FAILURE;
                    }
                }
            }
            None => break,
        }
    }

    if let Err(e) = executor.finish() {
        eprintln!("Failed to finish execution: {:?}", e);
        return ExitCode::FAILURE;
    }

    // Write flamegraph output if requested
    if let (Some(output_path), Some(generator)) = (flamegraph_path, generator) {
        let file = match File::create(&output_path) {
            Ok(f) => f,
            Err(e) => {
                eprintln!("Failed to create flamegraph output file: {}", e);
                return ExitCode::FAILURE;
            }
        };
        let mut writer = BufWriter::new(file);
        if let Err(e) = generator.write_folded(&mut writer) {
            eprintln!("Failed to write flamegraph output: {:?}", e);
            return ExitCode::FAILURE;
        }

        eprintln!(
            "Flamegraph written to {:?} ({} instructions)",
            output_path,
            generator.total_instructions()
        );
    }

    ExitCode::SUCCESS
}

fn cmd_prove(elf_path: PathBuf, output_path: PathBuf, blowup: Option<u8>, time: bool) -> ExitCode {
    eprintln!("Reading ELF file...");
    let elf_data = match std::fs::read(&elf_path) {
        Ok(data) => data,
        Err(e) => {
            eprintln!("Failed to read ELF file: {}", e);
            return ExitCode::FAILURE;
        }
    };

    #[cfg(feature = "jemalloc-stats")]
    let tracker = heap_tracker::HeapTracker::start();

    let start = Instant::now();
    let proof = match blowup {
        Some(b) => {
            let opts = match GoldilocksCubicProofOptions::with_blowup(b) {
                Ok(opts) => opts,
                Err(e) => {
                    eprintln!("Invalid proof options: {e}");
                    return ExitCode::FAILURE;
                }
            };
            eprintln!(
                "Generating proof (blowup={b}, queries={})...",
                opts.fri_number_of_queries
            );
            prover::prove_with_options(&elf_data, vec![], &opts, &Default::default())
        }
        None => {
            eprintln!("Generating proof...");
            prover::prove(&elf_data)
        }
    };
    let prove_elapsed = start.elapsed();
    let proof = match proof {
        Ok(proof) => proof,
        Err(e) => {
            eprintln!("Proof generation failed: {}", e);
            return ExitCode::FAILURE;
        }
    };

    eprintln!("Writing proof...");
    let file = match File::create(&output_path) {
        Ok(f) => f,
        Err(e) => {
            eprintln!("Failed to create output file: {}", e);
            return ExitCode::FAILURE;
        }
    };
    let mut writer = BufWriter::new(file);

    let bytes = match bincode::serialize(&proof) {
        Ok(b) => b,
        Err(e) => {
            eprintln!("Failed to serialize proof: {}", e);
            return ExitCode::FAILURE;
        }
    };

    if let Err(e) = writer.write_all(&bytes) {
        eprintln!("Failed to write proof: {}", e);
        return ExitCode::FAILURE;
    }

    eprintln!("Proof written to {:?}", output_path);
    if time {
        println!("Proving time: {:.3}s", prove_elapsed.as_secs_f64());
    }
    #[cfg(feature = "jemalloc-stats")]
    {
        let peak_bytes = tracker.stop();
        println!("Peak heap: {} MB", peak_bytes / (1024 * 1024));
    }
    ExitCode::SUCCESS
}

fn cmd_verify(proof_path: PathBuf, elf_path: PathBuf, blowup: Option<u8>, time: bool) -> ExitCode {
    eprintln!("Reading ELF file...");
    let elf_data = match std::fs::read(&elf_path) {
        Ok(data) => data,
        Err(e) => {
            eprintln!("Failed to read ELF file: {}", e);
            return ExitCode::FAILURE;
        }
    };

    eprintln!("Reading proof...");
    let proof_bytes = match std::fs::read(&proof_path) {
        Ok(b) => b,
        Err(e) => {
            eprintln!("Failed to read proof file: {}", e);
            return ExitCode::FAILURE;
        }
    };

    let proof: VmProof = match bincode::deserialize(&proof_bytes) {
        Ok(p) => p,
        Err(e) => {
            eprintln!("Failed to deserialize proof: {}", e);
            return ExitCode::FAILURE;
        }
    };

    eprintln!("Verifying proof...");
    let start = Instant::now();
    let result = match blowup {
        Some(b) => {
            let opts = match GoldilocksCubicProofOptions::with_blowup(b) {
                Ok(opts) => opts,
                Err(e) => {
                    eprintln!("Invalid proof options: {e}");
                    return ExitCode::FAILURE;
                }
            };
            prover::verify_with_options(&proof, &elf_data, &opts)
        }
        None => prover::verify(&proof, &elf_data),
    };
    let verify_elapsed = start.elapsed();
    let result = match result {
        Ok(valid) => valid,
        Err(e) => {
            eprintln!("Verification error: {}", e);
            return ExitCode::FAILURE;
        }
    };

    if result {
        eprintln!("Verification succeeded!");
        if time {
            println!("Verification time: {:.3}s", verify_elapsed.as_secs_f64());
        }
        ExitCode::SUCCESS
    } else {
        eprintln!("Verification failed!");
        ExitCode::FAILURE
    }
}