make various parts of basic_opt optional

fuzz/fuzz_targets/differential.rs

@@ -2,7 +2,7 @@
 use libfuzzer_sys::fuzz_target;
 use std::sync::atomic::{AtomicU64, Ordering};
 
-use waffle::{FrontendOptions, Module};
+use waffle::{FrontendOptions, Module, OptOptions};
 
 fuzz_target!(|module: waffle::fuzzing::ArbitraryModule| {
     let module = module.0;
@@ -37,7 +37,7 @@ fuzz_target!(|module: waffle::fuzzing::ArbitraryModule| {
     let mut parsed_module =
         Module::from_wasm_bytes(&orig_bytes[..], &FrontendOptions::default()).unwrap();
     parsed_module.expand_all_funcs().unwrap();
-    parsed_module.per_func_body(|body| body.optimize());
+    parsed_module.per_func_body(|body| body.optimize(&OptOptions::default()));
     let roundtrip_bytes = parsed_module.to_wasm_bytes().unwrap();
 
     if let Ok(filename) = std::env::var("FUZZ_DUMP_WASM") {

fuzz/fuzz_targets/opt_diff.rs

@@ -1,7 +1,7 @@
 #![no_main]
 use libfuzzer_sys::fuzz_target;
 
-use waffle::{FrontendOptions, InterpContext, InterpResult, Module};
+use waffle::{FrontendOptions, InterpContext, InterpResult, Module, OptOptions};
 
 fuzz_target!(|module: waffle::fuzzing::ArbitraryModule| {
     let module = module.0;
@@ -48,7 +48,7 @@ fuzz_target!(|module: waffle::fuzzing::ArbitraryModule| {
     }
 
     let mut opt_module = parsed_module.clone();
-    opt_module.per_func_body(|body| body.optimize());
+    parsed_module.per_func_body(|body| body.optimize(&OptOptions::default()));
     opt_module.per_func_body(|body| body.convert_to_max_ssa(None));
 
     let mut opt_ctx = InterpContext::new(&opt_module).unwrap();

fuzz/fuzz_targets/roundtrip.rs

@@ -1,7 +1,7 @@
 #![no_main]
 use libfuzzer_sys::fuzz_target;
 
-use waffle::{FrontendError, FrontendOptions, Module};
+use waffle::{FrontendError, FrontendOptions, Module, OptOptions};
 
 fuzz_target!(|module: wasm_smith::Module| {
     let _ = env_logger::try_init();
@@ -26,6 +26,6 @@ fuzz_target!(|module: wasm_smith::Module| {
             }
         };
     parsed_module.expand_all_funcs().unwrap();
-    parsed_module.per_func_body(|body| body.optimize());
+    parsed_module.per_func_body(|body| body.optimize(&OptOptions::default()));
     let _ = parsed_module.to_wasm_bytes();
 });

src/bin/waffle-util.rs

@@ -5,7 +5,7 @@ use log::debug;
 use std::path::PathBuf;
 use structopt::StructOpt;
 use waffle::InterpContext;
-use waffle::{entity::EntityRef, FrontendOptions, Func, Module};
+use waffle::{entity::EntityRef, FrontendOptions, Func, Module, OptOptions};
 
 #[derive(Debug, StructOpt)]
 #[structopt(name = "waffle-util", about = "WAFFLE utility.")]
@@ -64,7 +64,7 @@ enum Command {
 fn apply_options(opts: &Options, module: &mut Module) -> Result<()> {
     module.expand_all_funcs()?;
     if opts.basic_opts {
-        module.per_func_body(|body| body.optimize());
+        module.per_func_body(|body| body.optimize(&OptOptions::default()));
     }
     if opts.max_ssa {
         module.per_func_body(|body| body.convert_to_max_ssa(None));

src/ir/func.rs

@@ -4,6 +4,7 @@ use crate::cfg::CFGInfo;
 use crate::entity::{EntityRef, EntityVec, PerEntity};
 use crate::frontend::parse_body;
 use crate::ir::SourceLoc;
+use crate::passes::basic_opt::OptOptions;
 use crate::pool::{ListPool, ListRef};
 use crate::{Func, Table};
 use anyhow::Result;
@@ -49,10 +50,10 @@ impl<'a> FuncDecl<'a> {
         }
     }
 
-    pub fn optimize(&mut self) {
+    pub fn optimize(&mut self, opts: &OptOptions) {
         match self {
             FuncDecl::Body(_, _, body) => {
-                body.optimize();
+                body.optimize(opts);
             }
             _ => {}
         }
@@ -171,11 +172,9 @@ impl FunctionBody {
         }
     }
 
-    pub fn optimize(&mut self) {
+    pub fn optimize(&mut self, opts: &OptOptions) {
         let cfg = crate::cfg::CFGInfo::new(self);
-        crate::passes::remove_phis::run(self, &cfg);
+        crate::passes::basic_opt::basic_opt(self, &cfg, opts);
-        crate::passes::basic_opt::gvn(self, &cfg);
-        crate::passes::remove_phis::run(self, &cfg);
         crate::passes::empty_blocks::run(self);
     }
 

src/lib.rs

@@ -24,5 +24,7 @@ pub use ops::{Ieee32, Ieee64, MemoryArg, Operator};
 mod interp;
 pub use interp::*;
 
+pub use passes::basic_opt::OptOptions;
+
 #[cfg(feature = "fuzzing")]
 pub mod fuzzing;

src/passes.rs

@@ -4,7 +4,6 @@ pub mod basic_opt;
 pub mod dom_pass;
 pub mod empty_blocks;
 pub mod maxssa;
-pub mod remove_phis;
 pub mod resolve_aliases;
 pub mod ssa;
 pub mod trace;

src/passes/basic_opt.rs

@@ -9,24 +9,47 @@ use crate::scoped_map::ScopedMap;
 use crate::Operator;
 use smallvec::{smallvec, SmallVec};
 
-pub fn gvn(body: &mut FunctionBody, cfg: &CFGInfo) {
+#[derive(Clone, Debug)]
-    dom_pass::<GVNPass>(
+pub struct OptOptions {
-        body,
+    pub gvn: bool,
-        cfg,
+    pub cprop: bool,
-        &mut GVNPass {
+    pub redundant_blockparams: bool,
+}
+
+impl std::default::Default for OptOptions {
+    fn default() -> Self {
+        OptOptions {
+            gvn: true,
+            cprop: true,
+            redundant_blockparams: true,
+        }
+    }
+}
+
+pub fn basic_opt(body: &mut FunctionBody, cfg: &CFGInfo, options: &OptOptions) {
+    loop {
+        let mut pass = BasicOptPass {
             map: ScopedMap::default(),
             cfg,
-        },
+            options,
-    );
+            changed: false,
+        };
+        dom_pass::<BasicOptPass>(body, cfg, &mut pass);
+        if !pass.changed {
+            break;
+        }
+    }
 }
 
 #[derive(Debug)]
-struct GVNPass<'a> {
+struct BasicOptPass<'a> {
     map: ScopedMap<ValueDef, Value>,
     cfg: &'a CFGInfo,
+    options: &'a OptOptions,
+    changed: bool,
 }
 
-impl<'a> DomtreePass for GVNPass<'a> {
+impl<'a> DomtreePass for BasicOptPass<'a> {
     fn enter(&mut self, block: Block, body: &mut FunctionBody) {
         self.map.push_level();
         self.optimize(block, body);
@@ -82,9 +105,9 @@ fn remove_all_from_vec<T: Clone>(v: &mut Vec<T>, indices: &[usize]) {
     v.truncate(out);
 }
 
-impl<'a> GVNPass<'a> {
+impl<'a> BasicOptPass<'a> {
     fn optimize(&mut self, block: Block, body: &mut FunctionBody) {
-        if block != body.entry {
+        if self.options.redundant_blockparams && block != body.entry {
             // Pass over blockparams, checking all inputs. If all inputs
             // resolve to the same SSA value, remove the blockparam and
             // make it an alias of that value. If all inputs resolve to
@@ -126,6 +149,10 @@ impl<'a> GVNPass<'a> {
                 }
             }
 
+            if !const_insts_to_insert.is_empty() || !blockparams_to_remove.is_empty() {
+                self.changed = true;
+            }
+
             for inst in const_insts_to_insert {
                 body.blocks[block].insts.insert(0, inst);
             }
@@ -154,18 +181,21 @@ impl<'a> GVNPass<'a> {
                     &mut ValueDef::Operator(_, args, _) | &mut ValueDef::Trace(_, args) => {
                         for i in 0..args.len() {
                             let val = body.arg_pool[args][i];
-                            let val = body.resolve_and_update_alias(val);
+                            let new_val = body.resolve_and_update_alias(val);
-                            body.arg_pool[args][i] = val;
+                            body.arg_pool[args][i] = new_val;
+                            self.changed |= new_val != val;
                         }
                     }
                     &mut ValueDef::PickOutput(ref mut val, ..) => {
                         let updated = body.resolve_and_update_alias(*val);
                         *val = updated;
+                        self.changed |= updated != *val;
                     }
                     _ => {}
                 }
 
                 // Try to constant-propagate.
+                if self.options.cprop {
                     if let ValueDef::Operator(op, args, ..) = &value {
                         let arg_values = body.arg_pool[*args]
                             .iter()
@@ -180,6 +210,7 @@ impl<'a> GVNPass<'a> {
                                     body.single_type_list(Type::I32),
                                 );
                                 body.values[inst] = value.clone();
+                                self.changed = true;
                             }
                             Some(ConstVal::I64(val)) => {
                                 value = ValueDef::Operator(
@@ -188,6 +219,7 @@ impl<'a> GVNPass<'a> {
                                     body.single_type_list(Type::I64),
                                 );
                                 body.values[inst] = value.clone();
+                                self.changed = true;
                             }
                             Some(ConstVal::F32(val)) => {
                                 value = ValueDef::Operator(
@@ -196,6 +228,7 @@ impl<'a> GVNPass<'a> {
                                     body.single_type_list(Type::F32),
                                 );
                                 body.values[inst] = value.clone();
+                                self.changed = true;
                             }
                             Some(ConstVal::F64(val)) => {
                                 value = ValueDef::Operator(
@@ -204,22 +237,26 @@ impl<'a> GVNPass<'a> {
                                     body.single_type_list(Type::F64),
                                 );
                                 body.values[inst] = value.clone();
+                                self.changed = true;
                             }
                             _ => {}
                         }
                     }
+                }
 
+                if self.options.gvn {
                     // GVN: look for already-existing copies of this
                     // value.
                     if let Some(value) = self.map.get(&value) {
                         body.set_alias(inst, *value);
                         i -= 1;
                         body.blocks[block].insts.remove(i);
+                        self.changed = true;
                         continue;
                     }
-
                     self.map.insert(value, inst);
                 }
             }
         }
+    }
 }

src/passes/remove_phis.rs

@@ -1,109 +0,0 @@
-//! Remove-useless-phis (blockparams) pass.
-
-use crate::cfg::CFGInfo;
-use crate::ir::*;
-
-fn all_equal(mut vals: impl Iterator<Item = Value>) -> Option<Value> {
-    match vals.next() {
-        Some(val) if vals.all(|other_val| other_val == val) => Some(val),
-        _ => None,
-    }
-}
-
-fn delete_indices<T: Copy>(vec: &mut Vec<T>, indices: &[usize]) {
-    let mut out = 0;
-    let mut indices_idx = 0;
-    for i in 0..vec.len() {
-        if indices_idx < indices.len() && indices[indices_idx] == i {
-            indices_idx += 1;
-            // Deleted!
-        } else {
-            if out < i {
-                vec[out] = vec[i];
-            }
-            out += 1;
-        }
-    }
-    if out < vec.len() {
-        vec.truncate(out);
-    }
-}
-
-pub fn run(func: &mut FunctionBody, cfg: &CFGInfo) {
-    // For every block, collect the arg-lists of preds. If a given
-    // blockparam has all the same values for an arg, replace the
-    // blockparam value with an alias to that one value, and then
-    // remove it from the blockparams and target-lists of all preds.
-
-    log::trace!(
-        "remove_phis: running on func:\n{}\n",
-        func.display_verbose("| ", None)
-    );
-
-    let mut deleted = vec![];
-    for &block in cfg.rpo.values() {
-        // Skip the entry block -- we can't remove any args, because
-        // there is also an implicit in-edge from the function entry
-        // with arguments.
-        if block == func.entry {
-            continue;
-        }
-
-        deleted.clear();
-
-        // Gather arg-lists from each pred's terminator.
-        let mut arglists = vec![];
-        for (i, &pred) in func.blocks[block].preds.iter().enumerate() {
-            let pos = func.blocks[block].pos_in_pred_succ[i];
-            func.blocks[pred].terminator.visit_target(pos, |target| {
-                assert_eq!(target.block, block);
-                assert_eq!(target.args.len(), func.blocks[block].params.len());
-                arglists.push(target.args.clone());
-            });
-        }
-
-        // For each arg-position, check if all args are the same. If
-        // so, rewrite value and mark index as deleted.
-        for i in 0..func.blocks[block].params.len() {
-            let blockparam = func.blocks[block].params[i].1;
-            let same = all_equal(
-                arglists
-                    .iter()
-                    .map(|arglist| func.resolve_alias(arglist[i])),
-            );
-            if let Some(val) = same {
-                if val != blockparam {
-                    log::trace!(
-                        "deleting blockparam {} from block {}: now {}",
-                        blockparam,
-                        block,
-                        val
-                    );
-                    func.values[blockparam] = ValueDef::Alias(val);
-                    deleted.push(i);
-                }
-            }
-        }
-
-        // If anything was deleted, remove the appropriate indices in
-        // the func's blockparams list and in targets' arg lists.
-        if !deleted.is_empty() {
-            delete_indices(&mut func.blocks[block].params, &deleted[..]);
-            for i in 0..func.blocks[block].preds.len() {
-                let pred = func.blocks[block].preds[i];
-                let pos = func.blocks[block].pos_in_pred_succ[i];
-                func.blocks[pred].terminator.update_target(pos, |target| {
-                    delete_indices(&mut target.args, &deleted[..]);
-                });
-            }
-
-            // Renumber blockparam values.
-            for (i, &(_, param)) in func.blocks[block].params.iter().enumerate() {
-                let ty = func.values[param].ty(&func.type_pool).unwrap();
-                func.values[param] = ValueDef::BlockParam(block, i as u32, ty);
-            }
-        }
-    }
-
-    log::trace!("remove_phis: done:\n{}\n", func.display_verbose("| ", None));
-}