Single function arithmetic programs

Author: cbeuw

difftest/src/main.rs

@@ -1,4 +1,5 @@
 #![feature(byte_slice_trim_ascii)]
+#![feature(iter_intersperse)]
 
 use core::panic;
 use std::{collections::HashMap, path::PathBuf, str::FromStr};
@@ -9,6 +10,7 @@ use difftest::{
     backend::{Backend, Cranelift, Miri, LLVM},
     run_diff_test,
 };
+use log::{info, error};
 
 fn main() {
     env_logger::init();
@@ -46,5 +48,19 @@ fn main() {
 
     backends.insert("llvm", Box::new(LLVM {}));
 
-    run_diff_test(&source, &backends);
+    info!(
+        "Difftesting {} with {}",
+        source.as_os_str().to_string_lossy(),
+        backends
+            .keys()
+            .copied()
+            .intersperse(", ")
+            .collect::<String>()
+    );
+    let results = run_diff_test(&source, &backends);
+    if results.len() == 1 {
+        info!("{} is all the same", source.as_os_str().to_string_lossy());
+    } else {
+        error!("{} didn't pass: {:?}", source.as_os_str().to_string_lossy(), results);
+    }
 }

fuzz.sh

@@ -0,0 +1,6 @@
+#!/bin/bash
+mkdir -p out
+for seed in {0..10}; do
+    target/release/fuzz $seed > out/$seed.rs
+    target/release/difftest out/$seed.rs
+done

fuzz/src/generation.rs

@@ -339,7 +339,7 @@ trait GenerateStatement {
 impl GenerateStatement for GenerationCtx {
     fn generate_assign(&mut self) -> Result<Statement> {
         let lhs_choices = PlaceSelector::new().maybe_uninit().into_iter(&self.pt);
-    
+
         self.make_choice(lhs_choices, |lhs| {
             debug!(
                 "generating an assignment statement with lhs ty {}",
@@ -551,10 +551,11 @@ impl GenerationCtx {
 
         self.enter_new_fn(&arg_tys, Ty::I32);
 
-        let statement_count = self.rng.get_mut().gen_range(0..=16);
-        debug!("generating a bb with {statement_count} statements");
+        let ret_node = self.pt.get_node(&Place::RETURN_SLOT).unwrap();
+        while !self.pt.is_place_init(ret_node) {
+            self.choose_statement();
+        }
 
-        (0..statement_count).for_each(|_| self.choose_statement());
         self.choose_terminator();
         self.program
     }

fuzz/src/main.rs

@@ -10,6 +10,7 @@ mod ty;
 use std::env::args;
 
 use crate::generation::GenerationCtx;
+use log::info;
 use mir::{serialize::Serialize, syntax::*};
 use petgraph::dot::Dot;
 use rand::{rngs::SmallRng, SeedableRng};
@@ -43,6 +44,7 @@ fn main() {
     // println!("{dot:?}");
 
     let seed: u64 = args().skip(1).next().unwrap().parse().unwrap();
+    info!("Generating a program with seed {seed}");
     let genctxt = GenerationCtx::new(seed);
     let program = genctxt.generate();
     println!("{}", program.serialize());