Add bugpoint command

Add the command `cargo run --release bugpoint crash.clif 2>/dev/null` to reduce test cases.

cranelift/Cargo.toml

@@ -41,6 +41,7 @@ wabt = { version = "0.7.0", optional = true }
 target-lexicon = "0.4.0"
 pretty_env_logger = "0.3.0"
 file-per-thread-logger = "0.1.2"
+indicatif = "0.11.0"
 
 [features]
 default = ["disas", "wasm"]

cranelift/src/bugpoint.rs

@@ -0,0 +1,850 @@
+//! CLI tool to reduce Cranelift IR files crashing during compilation.
+
+use crate::disasm::{PrintRelocs, PrintTraps};
+use crate::utils::{parse_sets_and_triple, read_to_string};
+use cranelift_codegen::ir::{
+    Ebb, FuncRef, Function, GlobalValueData, Inst, InstBuilder, InstructionData, StackSlots,
+    TrapCode,
+};
+use cranelift_codegen::isa::TargetIsa;
+use cranelift_codegen::Context;
+use cranelift_entity::PrimaryMap;
+use cranelift_reader::parse_test;
+use std::collections::HashMap;
+use std::path::Path;
+
+use indicatif::{ProgressBar, ProgressDrawTarget, ProgressStyle};
+
+pub fn run(
+    filename: &str,
+    flag_set: &[String],
+    flag_isa: &str,
+    verbose: bool,
+) -> Result<(), String> {
+    let parsed = parse_sets_and_triple(flag_set, flag_isa)?;
+    let fisa = parsed.as_fisa();
+
+    let path = Path::new(&filename).to_path_buf();
+
+    let buffer = read_to_string(&path).map_err(|e| format!("{}: {}", filename, e))?;
+    let test_file = parse_test(&buffer, None, None).map_err(|e| format!("{}: {}", filename, e))?;
+
+    // If we have an isa from the command-line, use that. Otherwise if the
+    // file contains a unique isa, use that.
+    let isa = if let Some(isa) = fisa.isa {
+        isa
+    } else if let Some(isa) = test_file.isa_spec.unique_isa() {
+        isa
+    } else {
+        return Err(String::from("compilation requires a target isa"));
+    };
+
+    std::env::set_var("RUST_BACKTRACE", "0"); // Disable backtraces to reduce verbosity
+
+    for (func, _) in test_file.functions {
+        let (orig_ebb_count, orig_inst_count) = (ebb_count(&func), inst_count(&func));
+
+        match reduce(isa, func, verbose) {
+            Ok((func, crash_msg)) => {
+                println!("Crash message: {}", crash_msg);
+
+                println!("\n{}", func);
+
+                println!(
+                    "{} ebbs {} insts -> {} ebbs {} insts",
+                    orig_ebb_count,
+                    orig_inst_count,
+                    ebb_count(&func),
+                    inst_count(&func)
+                );
+            }
+            Err(err) => println!("Warning: {}", err),
+        }
+    }
+
+    Ok(())
+}
+
+enum MutationKind {
+    /// The mutation reduced the amount of instructions or ebbs.
+    Shrinked,
+    /// The mutation only changed an instruction. Performing another round of mutations may only
+    /// reduce the test case if another mutation shrank the test case.
+    Changed,
+}
+
+trait Mutator {
+    fn name(&self) -> &'static str;
+
+    fn mutation_count(&self, func: &Function) -> Option<usize>;
+
+    fn mutate(&mut self, func: Function) -> Option<(Function, String, MutationKind)>;
+
+    fn reduce(
+        &mut self,
+        ccc: &mut CrashCheckContext,
+        mut func: Function,
+        progress_bar_prefix: String,
+        verbose: bool,
+        should_keep_reducing: &mut bool,
+    ) -> Function {
+        let progress = ProgressBar::with_draw_target(
+            self.mutation_count(&func).unwrap_or(0) as u64,
+            ProgressDrawTarget::stdout(),
+        );
+        progress.set_style(
+            ProgressStyle::default_bar().template("{bar:60} {prefix:40} {pos:>4}/{len:>4} {msg}"),
+        );
+
+        progress.set_prefix(&(progress_bar_prefix + &format!(" phase {}", self.name())));
+
+        for _ in 0..10000 {
+            progress.inc(1);
+
+            let (mutated_func, msg, mutation_kind) = match self.mutate(func.clone()) {
+                Some(res) => res,
+                None => {
+                    break;
+                }
+            };
+
+            progress.set_message(&msg);
+
+            match ccc.check_for_crash(&mutated_func) {
+                CheckResult::Succeed => {
+                    // Shrinking didn't hit the problem anymore, discard changes.
+                    continue;
+                }
+                CheckResult::Crash(_) => {
+                    // Panic remained while shrinking, make changes definitive.
+                    func = mutated_func;
+                    match mutation_kind {
+                        MutationKind::Shrinked => {
+                            *should_keep_reducing = true;
+                            if verbose {
+                                progress.println(format!("{}: shrink", msg));
+                            }
+                        }
+                        MutationKind::Changed => {
+                            if verbose {
+                                progress.println(format!("{}: changed", msg));
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        progress.set_message("done");
+        progress.finish();
+
+        func
+    }
+}
+
+/// Try to remove instructions.
+struct RemoveInst {
+    ebb: Ebb,
+    inst: Inst,
+}
+
+impl RemoveInst {
+    fn new(func: &Function) -> Self {
+        let first_ebb = func.layout.entry_block().unwrap();
+        let first_inst = func.layout.first_inst(first_ebb).unwrap();
+        Self {
+            ebb: first_ebb,
+            inst: first_inst,
+        }
+    }
+}
+
+impl Mutator for RemoveInst {
+    fn name(&self) -> &'static str {
+        "remove inst"
+    }
+
+    fn mutation_count(&self, func: &Function) -> Option<usize> {
+        Some(inst_count(func))
+    }
+
+    fn mutate(&mut self, mut func: Function) -> Option<(Function, String, MutationKind)> {
+        if let Some((prev_ebb, prev_inst)) =
+            next_inst_ret_prev(&func, &mut self.ebb, &mut self.inst)
+        {
+            func.layout.remove_inst(prev_inst);
+            if func.layout.ebb_insts(prev_ebb).next().is_none() {
+                // Make sure empty ebbs are removed, as `next_inst_ret_prev` depends on non empty ebbs
+                func.layout.remove_ebb(prev_ebb);
+                Some((
+                    func,
+                    format!("Remove inst {} and empty ebb {}", prev_inst, prev_ebb),
+                    MutationKind::Shrinked,
+                ))
+            } else {
+                Some((
+                    func,
+                    format!("Remove inst {}", prev_inst),
+                    MutationKind::Shrinked,
+                ))
+            }
+        } else {
+            None
+        }
+    }
+}
+
+/// Try to replace instructions with `iconst`.
+struct ReplaceInstWithIconst {
+    ebb: Ebb,
+    inst: Inst,
+}
+
+impl ReplaceInstWithIconst {
+    fn new(func: &Function) -> Self {
+        let first_ebb = func.layout.entry_block().unwrap();
+        let first_inst = func.layout.first_inst(first_ebb).unwrap();
+        Self {
+            ebb: first_ebb,
+            inst: first_inst,
+        }
+    }
+}
+
+impl Mutator for ReplaceInstWithIconst {
+    fn name(&self) -> &'static str {
+        "replace inst with iconst"
+    }
+
+    fn mutation_count(&self, func: &Function) -> Option<usize> {
+        Some(inst_count(func))
+    }
+
+    fn mutate(&mut self, mut func: Function) -> Option<(Function, String, MutationKind)> {
+        if let Some((_prev_ebb, prev_inst)) =
+            next_inst_ret_prev(&func, &mut self.ebb, &mut self.inst)
+        {
+            let results = func.dfg.inst_results(prev_inst);
+            if results.len() == 1 {
+                let ty = func.dfg.value_type(results[0]);
+                func.dfg.replace(prev_inst).iconst(ty, 0);
+                Some((
+                    func,
+                    format!("Replace inst {} with iconst.{}", prev_inst, ty),
+                    MutationKind::Changed,
+                ))
+            } else {
+                Some((func, format!(""), MutationKind::Changed))
+            }
+        } else {
+            None
+        }
+    }
+}
+
+/// Try to replace instructions with `trap`.
+struct ReplaceInstWithTrap {
+    ebb: Ebb,
+    inst: Inst,
+}
+
+impl ReplaceInstWithTrap {
+    fn new(func: &Function) -> Self {
+        let first_ebb = func.layout.entry_block().unwrap();
+        let first_inst = func.layout.first_inst(first_ebb).unwrap();
+        Self {
+            ebb: first_ebb,
+            inst: first_inst,
+        }
+    }
+}
+
+impl Mutator for ReplaceInstWithTrap {
+    fn name(&self) -> &'static str {
+        "replace inst with trap"
+    }
+
+    fn mutation_count(&self, func: &Function) -> Option<usize> {
+        Some(inst_count(func))
+    }
+
+    fn mutate(&mut self, mut func: Function) -> Option<(Function, String, MutationKind)> {
+        if let Some((_prev_ebb, prev_inst)) =
+            next_inst_ret_prev(&func, &mut self.ebb, &mut self.inst)
+        {
+            func.dfg.replace(prev_inst).trap(TrapCode::User(0));
+            Some((
+                func,
+                format!("Replace inst {} with trap", prev_inst),
+                MutationKind::Changed,
+            ))
+        } else {
+            None
+        }
+    }
+}
+
+/// Try to remove an ebb.
+struct RemoveEbb {
+    ebb: Ebb,
+}
+
+impl RemoveEbb {
+    fn new(func: &Function) -> Self {
+        Self {
+            ebb: func.layout.entry_block().unwrap(),
+        }
+    }
+}
+
+impl Mutator for RemoveEbb {
+    fn name(&self) -> &'static str {
+        "remove ebb"
+    }
+
+    fn mutation_count(&self, func: &Function) -> Option<usize> {
+        Some(ebb_count(func))
+    }
+
+    fn mutate(&mut self, mut func: Function) -> Option<(Function, String, MutationKind)> {
+        if let Some(next_ebb) = func.layout.next_ebb(self.ebb) {
+            self.ebb = next_ebb;
+            while let Some(inst) = func.layout.last_inst(self.ebb) {
+                func.layout.remove_inst(inst);
+            }
+            func.layout.remove_ebb(self.ebb);
+            Some((
+                func,
+                format!("Remove ebb {}", next_ebb),
+                MutationKind::Shrinked,
+            ))
+        } else {
+            None
+        }
+    }
+}
+
+/// Try to remove unused entities.
+struct RemoveUnusedEntities {
+    kind: u32,
+}
+
+impl RemoveUnusedEntities {
+    fn new() -> Self {
+        Self { kind: 0 }
+    }
+}
+
+impl Mutator for RemoveUnusedEntities {
+    fn name(&self) -> &'static str {
+        "remove unused entities"
+    }
+
+    fn mutation_count(&self, _func: &Function) -> Option<usize> {
+        Some(4)
+    }
+
+    fn mutate(&mut self, mut func: Function) -> Option<(Function, String, MutationKind)> {
+        let name = match self.kind {
+            0 => {
+                let mut ext_func_usage_map = HashMap::new();
+                for ebb in func.layout.ebbs() {
+                    for inst in func.layout.ebb_insts(ebb) {
+                        match func.dfg[inst] {
+                            // Add new cases when there are new instruction formats taking a `FuncRef`.
+                            InstructionData::Call { func_ref, .. }
+                            | InstructionData::FuncAddr { func_ref, .. } => {
+                                ext_func_usage_map
+                                    .entry(func_ref)
+                                    .or_insert_with(Vec::new)
+                                    .push(inst);
+                            }
+                            _ => {}
+                        }
+                    }
+                }
+
+                let mut ext_funcs = PrimaryMap::new();
+
+                for (func_ref, ext_func_data) in func.dfg.ext_funcs.clone().into_iter() {
+                    if let Some(func_ref_usage) = ext_func_usage_map.get(&func_ref) {
+                        let new_func_ref = ext_funcs.push(ext_func_data.clone());
+                        for &inst in func_ref_usage {
+                            match func.dfg[inst] {
+                                // Keep in sync with the above match.
+                                InstructionData::Call {
+                                    ref mut func_ref, ..
+                                }
+                                | InstructionData::FuncAddr {
+                                    ref mut func_ref, ..
+                                } => {
+                                    *func_ref = new_func_ref;
+                                }
+                                _ => unreachable!(),
+                            }
+                        }
+                    }
+                }
+
+                func.dfg.ext_funcs = ext_funcs;
+
+                "Remove unused ext funcs"
+            }
+            1 => {
+                #[derive(Copy, Clone)]
+                enum SigRefUser {
+                    Instruction(Inst),
+                    ExtFunc(FuncRef),
+                }
+
+                let mut signatures_usage_map = HashMap::new();
+                for ebb in func.layout.ebbs() {
+                    for inst in func.layout.ebb_insts(ebb) {
+                        match func.dfg[inst] {
+                            // Add new cases when there are new instruction formats taking a `SigRef`.
+                            InstructionData::CallIndirect { sig_ref, .. } => {
+                                signatures_usage_map
+                                    .entry(sig_ref)
+                                    .or_insert_with(Vec::new)
+                                    .push(SigRefUser::Instruction(inst));
+                            }
+                            _ => {}
+                        }
+                    }
+                }
+                for (func_ref, ext_func_data) in func.dfg.ext_funcs.iter() {
+                    signatures_usage_map
+                        .entry(ext_func_data.signature)
+                        .or_insert_with(Vec::new)
+                        .push(SigRefUser::ExtFunc(func_ref));
+                }
+
+                let mut signatures = PrimaryMap::new();
+
+                for (sig_ref, sig_data) in func.dfg.signatures.clone().into_iter() {
+                    if let Some(sig_ref_usage) = signatures_usage_map.get(&sig_ref) {
+                        let new_sig_ref = signatures.push(sig_data.clone());
+                        for &sig_ref_user in sig_ref_usage {
+                            match sig_ref_user {
+                                SigRefUser::Instruction(inst) => match func.dfg[inst] {
+                                    // Keep in sync with the above match.
+                                    InstructionData::CallIndirect {
+                                        ref mut sig_ref, ..
+                                    } => {
+                                        *sig_ref = new_sig_ref;
+                                    }
+                                    _ => unreachable!(),
+                                },
+                                SigRefUser::ExtFunc(func_ref) => {
+                                    func.dfg.ext_funcs[func_ref].signature = new_sig_ref;
+                                }
+                            }
+                        }
+                    }
+                }
+
+                func.dfg.signatures = signatures;
+
+                "Remove unused signatures"
+            }
+            2 => {
+                let mut stack_slot_usage_map = HashMap::new();
+                for ebb in func.layout.ebbs() {
+                    for inst in func.layout.ebb_insts(ebb) {
+                        match func.dfg[inst] {
+                            // Add new cases when there are new instruction formats taking a `StackSlot`.
+                            InstructionData::StackLoad { stack_slot, .. }
+                            | InstructionData::StackStore { stack_slot, .. } => {
+                                stack_slot_usage_map
+                                    .entry(stack_slot)
+                                    .or_insert_with(Vec::new)
+                                    .push(inst);
+                            }
+
+                            InstructionData::RegSpill { dst, .. } => {
+                                stack_slot_usage_map
+                                    .entry(dst)
+                                    .or_insert_with(Vec::new)
+                                    .push(inst);
+                            }
+                            InstructionData::RegFill { src, .. } => {
+                                stack_slot_usage_map
+                                    .entry(src)
+                                    .or_insert_with(Vec::new)
+                                    .push(inst);
+                            }
+                            _ => {}
+                        }
+                    }
+                }
+
+                let mut stack_slots = StackSlots::new();
+
+                for (stack_slot, stack_slot_data) in func.stack_slots.clone().iter() {
+                    if let Some(stack_slot_usage) = stack_slot_usage_map.get(&stack_slot) {
+                        let new_stack_slot = stack_slots.push(stack_slot_data.clone());
+                        for &inst in stack_slot_usage {
+                            match &mut func.dfg[inst] {
+                                // Keep in sync with the above match.
+                                InstructionData::StackLoad { stack_slot, .. }
+                                | InstructionData::StackStore { stack_slot, .. } => {
+                                    *stack_slot = new_stack_slot;
+                                }
+                                InstructionData::RegSpill { dst, .. } => {
+                                    *dst = new_stack_slot;
+                                }
+                                InstructionData::RegFill { src, .. } => {
+                                    *src = new_stack_slot;
+                                }
+                                _ => unreachable!(),
+                            }
+                        }
+                    }
+                }
+
+                func.stack_slots = stack_slots;
+
+                "Remove unused stack slots"
+            }
+            3 => {
+                let mut global_value_usage_map = HashMap::new();
+                for ebb in func.layout.ebbs() {
+                    for inst in func.layout.ebb_insts(ebb) {
+                        match func.dfg[inst] {
+                            // Add new cases when there are new instruction formats taking a `GlobalValue`.
+                            InstructionData::UnaryGlobalValue { global_value, .. } => {
+                                global_value_usage_map
+                                    .entry(global_value)
+                                    .or_insert_with(Vec::new)
+                                    .push(inst);
+                            }
+                            _ => {}
+                        }
+                    }
+                }
+
+                for (_global_value, global_value_data) in func.global_values.iter() {
+                    match *global_value_data {
+                        GlobalValueData::VMContext | GlobalValueData::Symbol { .. } => {}
+                        // These can create cyclic references, which cause complications. Just skip
+                        // the global value removal for now.
+                        // FIXME Handle them in a better way.
+                        GlobalValueData::Load { base: _, .. }
+                        | GlobalValueData::IAddImm { base: _, .. } => return None,
+                    }
+                }
+
+                let mut global_values = PrimaryMap::new();
+
+                for (global_value, global_value_data) in func.global_values.clone().into_iter() {
+                    if let Some(global_value_usage) = global_value_usage_map.get(&global_value) {
+                        let new_global_value = global_values.push(global_value_data.clone());
+                        for &inst in global_value_usage {
+                            match &mut func.dfg[inst] {
+                                // Keep in sync with the above match.
+                                InstructionData::UnaryGlobalValue { global_value, .. } => {
+                                    *global_value = new_global_value;
+                                }
+                                _ => unreachable!(),
+                            }
+                        }
+                    }
+                }
+
+                func.global_values = global_values;
+
+                "Remove unused global values"
+            }
+            _ => return None,
+        };
+        self.kind += 1;
+        Some((func, name.to_owned(), MutationKind::Changed))
+    }
+}
+
+fn next_inst_ret_prev(func: &Function, ebb: &mut Ebb, inst: &mut Inst) -> Option<(Ebb, Inst)> {
+    let prev = (*ebb, *inst);
+    if let Some(next_inst) = func.layout.next_inst(*inst) {
+        *inst = next_inst;
+        return Some(prev);
+    } else if let Some(next_ebb) = func.layout.next_ebb(*ebb) {
+        *ebb = next_ebb;
+        *inst = func.layout.first_inst(*ebb).expect("no inst");
+        return Some(prev);
+    } else {
+        return None;
+    }
+}
+
+fn ebb_count(func: &Function) -> usize {
+    func.layout.ebbs().count()
+}
+
+fn inst_count(func: &Function) -> usize {
+    func.layout
+        .ebbs()
+        .map(|ebb| func.layout.ebb_insts(ebb).count())
+        .sum()
+}
+
+fn resolve_aliases(func: &mut Function) {
+    for ebb in func.layout.ebbs() {
+        for inst in func.layout.ebb_insts(ebb) {
+            func.dfg.resolve_aliases_in_arguments(inst);
+        }
+    }
+}
+
+fn reduce(
+    isa: &TargetIsa,
+    mut func: Function,
+    verbose: bool,
+) -> Result<(Function, String), String> {
+    let mut ccc = CrashCheckContext::new(isa);
+
+    match ccc.check_for_crash(&func) {
+        CheckResult::Succeed => {
+            return Err(format!(
+                "Given function compiled successfully or gave an verifier error."
+            ));
+        }
+        CheckResult::Crash(_) => {}
+    }
+
+    resolve_aliases(&mut func);
+
+    for pass_idx in 0..100 {
+        let mut should_keep_reducing = false;
+        let mut phase = 0;
+
+        loop {
+            let mut mutator = match phase {
+                0 => Box::new(RemoveInst::new(&func)) as Box<dyn Mutator>,
+                1 => Box::new(ReplaceInstWithIconst::new(&func)) as Box<dyn Mutator>,
+                2 => Box::new(ReplaceInstWithTrap::new(&func)) as Box<dyn Mutator>,
+                3 => Box::new(RemoveEbb::new(&func)) as Box<dyn Mutator>,
+                4 => Box::new(RemoveUnusedEntities::new()) as Box<dyn Mutator>,
+                _ => break,
+            };
+
+            func = mutator.reduce(
+                &mut ccc,
+                func,
+                format!("pass {}", pass_idx),
+                verbose,
+                &mut should_keep_reducing,
+            );
+
+            phase += 1;
+        }
+
+        if !should_keep_reducing {
+            // No new shrinking opportunities have been found this pass. This means none will ever
+            // be found. Skip the rest of the passes over the function.
+            break;
+        }
+    }
+
+    let crash_msg = match ccc.check_for_crash(&func) {
+        CheckResult::Succeed => unreachable!("Used to crash, but doesn't anymore???"),
+        CheckResult::Crash(crash_msg) => crash_msg,
+    };
+
+    Ok((func, crash_msg))
+}
+
+struct CrashCheckContext<'a> {
+    /// Cached `Context`, to prevent repeated allocation.
+    context: Context,
+
+    /// The target isa to compile for.
+    isa: &'a TargetIsa,
+}
+
+fn get_panic_string(panic: Box<std::any::Any>) -> String {
+    let panic = match panic.downcast::<&'static str>() {
+        Ok(panic_msg) => panic_msg.to_owned(),
+        Err(panic) => panic,
+    };
+    match panic.downcast::<String>() {
+        Ok(panic_msg) => *panic_msg,
+        Err(_) => "Box<Any>".to_owned(),
+    }
+}
+
+enum CheckResult {
+    /// The function compiled fine, or the verifier noticed an error.
+    Succeed,
+
+    /// The compilation of the function panicked.
+    Crash(String),
+}
+
+impl<'a> CrashCheckContext<'a> {
+    fn new(isa: &'a TargetIsa) -> Self {
+        CrashCheckContext {
+            context: Context::new(),
+            isa,
+        }
+    }
+
+    #[cfg_attr(test, allow(unreachable_code))]
+    fn check_for_crash(&mut self, func: &Function) -> CheckResult {
+        self.context.clear();
+        self.context.func = func.clone();
+
+        use std::io::Write;
+        std::io::stdout().flush().unwrap(); // Flush stdout to sync with panic messages on stderr
+
+        match std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| {
+            cranelift_codegen::verifier::verify_function(&func, self.isa).err()
+        })) {
+            Ok(Some(_)) => return CheckResult::Succeed,
+            Ok(None) => {}
+            // The verifier panicked. compiling it will probably give the same panic.
+            // We treat it as succeeding to make it possible to reduce for the actual error.
+            // FIXME prevent verifier panic on removing ebb1
+            Err(_) => return CheckResult::Succeed,
+        }
+
+        #[cfg(test)]
+        {
+            // For testing purposes we emulate a panic caused by the existence of
+            // a `call` instruction.
+            let contains_call = func.layout.ebbs().any(|ebb| {
+                func.layout.ebb_insts(ebb).any(|inst| match func.dfg[inst] {
+                    InstructionData::Call { .. } => true,
+                    _ => false,
+                })
+            });
+            if contains_call {
+                return CheckResult::Crash("test crash".to_string());
+            } else {
+                return CheckResult::Succeed;
+            }
+        }
+
+        let old_panic_hook = std::panic::take_hook();
+        std::panic::set_hook(Box::new(|_| {})); // silence panics
+
+        let res = match std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| {
+            let mut relocs = PrintRelocs::new(false);
+            let mut traps = PrintTraps::new(false);
+            let mut mem = vec![];
+
+            let _ = self
+                .context
+                .compile_and_emit(self.isa, &mut mem, &mut relocs, &mut traps);
+        })) {
+            Ok(()) => CheckResult::Succeed,
+            Err(err) => CheckResult::Crash(get_panic_string(err)),
+        };
+
+        std::panic::set_hook(old_panic_hook);
+
+        res
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_reduce() {
+        const TEST: &'static str = include_str!("./bugpoint_test.clif");
+
+        let test_file = parse_test(TEST, None, None).unwrap();
+
+        // If we have an isa from the command-line, use that. Otherwise if the
+        // file contains a unique isa, use that.
+        let isa = test_file.isa_spec.unique_isa().expect("Unknown isa");
+
+        for (func, _) in test_file.functions {
+            let (func, crash_msg) = reduce(isa, func, false).expect("Couldn't reduce test case");
+
+            assert_eq!(crash_msg, "test crash");
+
+            assert_eq!(
+                format!("{}", func),
+                "function u0:0(i64, i64, i64) system_v {
+    sig0 = (i64, i64, i16, i64, i64, i64, i64, i64) system_v
+    fn0 = u0:95 sig0
+
+ebb0(v0: i64, v1: i64, v2: i64):
+    v113 -> v1
+    v124 -> v1
+    v136 -> v1
+    v148 -> v1
+    v160 -> v1
+    v185 -> v1
+    v222 -> v1
+    v237 -> v1
+    v241 -> v1
+    v256 -> v1
+    v262 -> v1
+    v105 = iconst.i64 0
+    trap user0
+
+ebb99(v804: i64, v1035: i64, v1037: i64, v1039: i64, v1044: i64, v1052: i16, v1057: i64):
+    v817 -> v1035
+    v830 -> v1037
+    v844 -> v1039
+    v857 -> v1039
+    v939 -> v1039
+    v1042 -> v1039
+    v1050 -> v1039
+    v908 -> v1044
+    v917 -> v1044
+    v921 -> v1044
+    v1043 -> v1044
+    v960 -> v1052
+    v990 -> v1052
+    v1051 -> v1052
+    v1055 -> v1052
+    v963 -> v1057
+    v1056 -> v1057
+    v1060 -> v1057
+    trap user0
+
+ebb101:
+    v829 = iconst.i64 0
+    v935 -> v829
+    v962 -> v829
+    v992 -> v829
+    v1036 -> v829
+    v1049 -> v829
+    trap user0
+
+ebb102:
+    v842 = iconst.i64 0
+    v976 -> v842
+    v989 -> v842
+    v1038 -> v842
+    v1061 -> v842
+    trap user0
+
+ebb105:
+    v883 = iconst.i64 0
+    v934 -> v883
+    v961 -> v883
+    v991 -> v883
+    v1005 -> v883
+    v1048 -> v883
+    trap user0
+
+ebb114:
+    v951 = iconst.i64 0
+    v988 -> v951
+    trap user0
+
+ebb117:
+    v987 = iconst.i64 0
+    call fn0(v0, v105, v1052, v883, v829, v987, v951, v842)
+    trap user0
+}
+"
+            );
+        }
+    }
+}

cranelift/src/clif-util.rs

@@ -28,6 +28,7 @@ use std::io::{self, Write};
 use std::option::Option;
 use std::process;
 
+mod bugpoint;
 mod cat;
 mod compile;
 mod disasm;
@@ -199,6 +200,14 @@ fn main() {
                 .arg(add_pass_arg())
                 .arg(add_debug_flag())
                 .arg(add_time_flag()),
+        )
+        .subcommand(
+            SubCommand::with_name("bugpoint")
+                .about("Reduce size of clif file causing panic during compilation.")
+                .arg(add_single_input_file_arg())
+                .arg(add_set_flag())
+                .arg(add_target_flag())
+                .arg(add_verbose_flag()),
         );
 
     let res_util = match app_cmds.get_matches().subcommand() {
@@ -284,6 +293,19 @@ fn main() {
 
             result
         }
+        ("bugpoint", Some(rest_cmd)) => {
+            let mut target_val: &str = "";
+            if let Some(clap_target) = rest_cmd.value_of("target") {
+                target_val = clap_target;
+            }
+
+            bugpoint::run(
+                rest_cmd.value_of("single-file").unwrap(),
+                &get_vec(rest_cmd.values_of("set")),
+                target_val,
+                rest_cmd.is_present("verbose"),
+            )
+        }
         _ => Err("Invalid subcommand.".to_owned()),
     };