38 lines
1,002 B
Rust
38 lines
1,002 B
Rust
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//! Implements methods for disassembling and printing a representation
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//! of compiled code, as well as tracing the runtime stack during
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//! execution.
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use std::io::{Stderr, Write};
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use tabwriter::TabWriter;
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use crate::opcode::OpCode;
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use crate::value::Value;
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/// Helper struct to trace runtime values and automatically flush the
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/// output after the value is dropped (i.e. in both success and
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/// failure exits from the VM).
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pub struct Tracer(TabWriter<Stderr>);
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impl Tracer {
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pub fn new() -> Self {
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let mut tw = TabWriter::new(std::io::stderr());
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write!(&mut tw, "=== runtime trace ===\n").ok();
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Tracer(tw)
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}
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pub fn trace(&mut self, op: &OpCode, ip: usize, stack: &[Value]) {
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write!(&mut self.0, "{:04} {:?}\t[ ", ip, op).ok();
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for val in stack {
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write!(&mut self.0, "{} ", val).ok();
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}
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write!(&mut self.0, "]\n").ok();
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}
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}
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impl Drop for Tracer {
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fn drop(&mut self) {
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self.0.flush().ok();
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}
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}
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