//! This mutator applies a random peephole transformation to the input Wasm module.

//!

//! It builds a minimal DFG (Data Flow Graph) from a random operator selected

//! from a random function inside the input Wasm. If this DFG is consistent and

//! has no side-effects, and egraph is constructed with

//! several hand-made rewriting rules. Random rewriting rules are selected and

//! the DFG is replaced by a new one. The final step assembles all together with the

//! new DFG, constructing a new equivalent Wasm binary.

//!

//!

//! To contribute with this specific mutator you can augment the defined

//! [rules][rules]. Those rewriting rules should be designed to

//! preserve the semantic of the original DFG or, in other case, should follow the filter

//! of the top config `preserve_semantics`.

//!

//! # Example

//!

//! ```ignore

//! rules.extend(rewrite!("strength-reduction";  "(i32.shl ?x i32.const.1)" <=> "(i32.mul ?x i32.const.2)"));

//! ```

//!

pub mod dfg;

pub mod eggsy;

pub mod rules;

use self::{

    dfg::DFGBuilder,

    eggsy::{

        analysis::PeepholeMutationAnalysis,

        encoder::{Encoder, expr2wasm::ResourceRequest},

        expr_enumerator::lazy_expand_aux,

        lang::*,

    },

};

use super::{Mutator, OperatorAndByteOffset};

use crate::{

    Error, ErrorKind, ModuleInfo, Result, WasmMutate,

    module::{PrimitiveTypeInfo, map_type},

};

use egg::{Rewrite, Runner};

use rand::RngExt;

use wasm_encoder::reencode::{Reencode, RoundtripReencoder};

use wasm_encoder::{CodeSection, ConstExpr, Function, GlobalSection, Module, ValType};

use wasmparser::{CodeSectionReader, FunctionBody, GlobalSectionReader, LocalsReader};

/// This mutator applies a random peephole transformation to the input Wasm module

#[derive(Clone)]

pub struct PeepholeMutator {

    max_tree_depth: u32,

    rules: Option<Vec<Rewrite<Lang, PeepholeMutationAnalysis>>>,

}

type EG = egg::EGraph<Lang, PeepholeMutationAnalysis>;

impl PeepholeMutator {

    /// Initializes a new PeepholeMutator with fuel

    pub const fn new(max_depth: u32) -> Self {

        PeepholeMutator {

            max_tree_depth: max_depth,

            rules: None,

        }

    }

    #[cfg(test)]

    pub fn new_with_rules(

        max_tree_depth: u32,

        rules: Vec<Rewrite<Lang, PeepholeMutationAnalysis>>,

    ) -> Self {

        PeepholeMutator {

            max_tree_depth,

            rules: Some(rules),

        }

    }

    // Collect and unfold params and locals, [x, ty, y, ty2] -> [ty....ty, ty2...ty2]

    fn get_func_locals(

        &self,

        info: &ModuleInfo,

        funcidx: u32,

        localsreader: &mut LocalsReader,

    ) -> Result<Vec<PrimitiveTypeInfo>> {

        let ftype = info.get_functype_idx(funcidx);

        match ftype {

            crate::module::TypeInfo::Func(tpe) => {

                let mut all_locals = Vec::new();

                for primitive in &tpe.params {

                    all_locals.push(*primitive)

                }

                for _ in 0..localsreader.get_count() {

                    let (count, ty) = localsreader.read()?;

                    let tymapped = PrimitiveTypeInfo::try_from(ty)?;

                    for _ in 0..count {

                        all_locals.push(tymapped);

                    }

                }

                Ok(all_locals)

            }

        }

    }

    fn random_mutate<'a>(

        &self,

        config: &'a mut WasmMutate,

        rules: &[Rewrite<Lang, PeepholeMutationAnalysis>],

    ) -> Result<Box<dyn Iterator<Item = Result<Module>> + 'a>> {

        let code_section = config.info().code.unwrap();

        let reader = config.info().get_binary_reader(code_section);

        let input_code_section = config.info().get_code_section().data;

        let sectionreader = CodeSectionReader::new(reader)?;

        let function_count = sectionreader.count();

        let mut function_to_mutate = config.rng().random_range(0..function_count);

        let mut visited_functions = 0;

        let readers = sectionreader.into_iter().collect::<Result<Vec<_>, _>>()?;

        loop {

            if visited_functions == function_count {

                return Err(Error::no_mutations_applicable());

            }

            let reader = readers[function_to_mutate as usize].clone();

            let operatorreader = reader.get_operators_reader()?;

            let mut localsreader = reader.get_locals_reader()?;

            let operators = operatorreader

                .into_iter_with_offsets()

                .collect::<wasmparser::Result<Vec<OperatorAndByteOffset>>>()?;

            let operatorscount = operators.len();

            let mut opcode_to_mutate = config.rng().random_range(0..operatorscount);

            log::trace!(

                "Selecting operator {opcode_to_mutate}/{operatorscount} from function {function_to_mutate}",

            );

            let locals = self.get_func_locals(

                config.info(),

                function_to_mutate + config.info().num_imported_functions(), /* the function type is shifted

                                                                            by the imported functions*/

                &mut localsreader,

            )?;

            let mut count = 0;

            loop {

                config.consume_fuel(1)?;

                if count == operatorscount {

                    break;

                }

                let mut dfg = DFGBuilder::new(config);

                let basicblock = dfg.get_bb_from_operator(opcode_to_mutate, &operators);

                let basicblock = match basicblock {

                    None => {

                        log::trace!(

                            "Basic block cannot be constructed for opcode {:?}",

                            &operators[opcode_to_mutate]

                        );

                        opcode_to_mutate = (opcode_to_mutate + 1) % operatorscount;

                        count += 1;

                        continue;

                    }

                    Some(basicblock) => basicblock,

                };

                let minidfg = dfg.get_dfg(config.info(), &operators, &basicblock);

                let minidfg = match minidfg {

                    None => {

                        log::trace!("DFG cannot be constructed for opcode {opcode_to_mutate}");

                        opcode_to_mutate = (opcode_to_mutate + 1) % operatorscount;

                        count += 1;

                        continue;

                    }

                    Some(minidfg) => minidfg,

                };

                if !minidfg.map.contains_key(&opcode_to_mutate) {

                    opcode_to_mutate = (opcode_to_mutate + 1) % operatorscount;

                    count += 1;

                    continue;

                }

                // Create an eterm expression from the basic block starting at oidx

                let start = minidfg.get_expr(opcode_to_mutate);

                if !minidfg.is_subtree_consistent_from_root() {

                    log::trace!("{start} is not consistent");

                    opcode_to_mutate = (opcode_to_mutate + 1) % operatorscount;

                    count += 1;

                    continue;

                };

                log::trace!(

                    "Trying to mutate\n\

                     {}\n\

                     at opcode {opcode_to_mutate} in function {function_to_mutate}",

                    start.pretty(30).trim(),

                );

                let analysis = PeepholeMutationAnalysis::new(config.info(), locals.clone());

                let runner = Runner::<Lang, PeepholeMutationAnalysis, ()>::new(analysis)

                    .with_iter_limit(1) // FIXME, the iterations should consume fuel from the actual mutator. Be careful with inner set time limits that can lead us to non-deterministic behavior

                    .with_expr(&start)

                    .run(rules);

                let mut egraph = runner.egraph;

                // In theory this will return the Id of the operator eterm

                let root = egraph.add_expr(&start);

                let startcmp = start.clone();

                // If the number of nodes in the egraph is not large, then

                // continue the search

                if egraph.total_number_of_nodes() <= 1 {

                    opcode_to_mutate = (opcode_to_mutate + 1) % operatorscount;

                    count += 1;

                    continue;

                };

                log::trace!(

                    "Egraph built, nodes count = {}",

                    egraph.total_number_of_nodes()

                );

                // At this point we spent some resource calculating basic block,

                // and constructing the egraph

                config.consume_fuel(1)?;

                // If reduction mode is requested then yield back the smallest

                // graph to start off with. For reduction cases that are

                // specifically trying to find an interesting test case though

                // the first reduction may not be interesting, so continue to

                // chain up the lazy expansions afterwards like we always do.

                let iter = if config.reduce {

                    let mut extractor = egg::Extractor::new(&egraph, egg::AstSize);

                    let (_best_cost, best_expr) = extractor.find_best(root);

                    Some(best_expr).into_iter()

                } else {

                    None.into_iter()

                };

                let iter = iter.chain(lazy_expand_aux(

                    root,

                    egraph.clone(),

                    self.max_tree_depth,

                    config.rng().random(),

                ));

                // Filter expression equal to the original one

                let iterator = iter

                    .filter(move |expr| !expr.to_string().eq(&startcmp.to_string()))

                    .map(move |expr| {

                        log::trace!("Yielding expression:\n{}", expr.pretty(60));

                        config.consume_fuel(1)?;

                        let mut newfunc = copy_locals(reader.clone())?;

                        let needed_resources = Encoder::build_function(

                            config,

                            opcode_to_mutate,

                            &expr,

                            &operators,

                            &basicblock,

                            &mut newfunc,

                            &minidfg,

                            &egraph,

                            input_code_section,

                        )?;

                        let mut codes = CodeSection::new();

                        let code_section = config.info().code.unwrap();

                        let reader = config.info().get_binary_reader(code_section);

                        let sectionreader = CodeSectionReader::new(reader)?;

                        // this mutator is applicable to internal functions, so

                        // it starts by randomly selecting an index between

                        // the imported functions and the total count, total=imported + internal

                        for (fidx, func) in sectionreader.into_iter().enumerate() {

                            let reader = func?;

                            if fidx as u32 == function_to_mutate {

                                codes.function(&newfunc);

                            } else {

                                codes.raw(reader.as_bytes());

                            }

                        }

                        // Process the outside function needed resources

                        // Needed globals

                        let mut new_global_section = GlobalSection::new();

                        // Reparse and reencode global section

                        if let Some(global_section) = config.info().globals {

                            // If the global section was already there, try to copy it to the

                            // new raw section

                            let reader = config.info().get_binary_reader(global_section);

                            let globalreader = GlobalSectionReader::new(reader)?;

                            RoundtripReencoder

                                .parse_global_section(&mut new_global_section, globalreader)?;

                        }

                        if needed_resources.len() > 0 {

                            log::trace!("Adding {} additional resources", needed_resources.len());

                        }

                        for resource in &needed_resources {

                            match resource {

                                ResourceRequest::Global {

                                    tpe: ty,

                                    mutable,

                                    shared,

                                } => {

                                    let (init, ty) = match ty {

                                        PrimitiveTypeInfo::I32 => {

                                            (ConstExpr::i32_const(0), ValType::I32)

                                        }

                                        PrimitiveTypeInfo::I64 => {

                                            (ConstExpr::i64_const(0), ValType::I64)

                                        }

                                        PrimitiveTypeInfo::F32 => {

                                            (ConstExpr::f32_const(0.0.into()), ValType::F32)

                                        }

                                        PrimitiveTypeInfo::F64 => {

                                            (ConstExpr::f64_const(0.0.into()), ValType::F64)

                                        }

                                        PrimitiveTypeInfo::V128 => {

                                            (ConstExpr::v128_const(0), ValType::V128)

                                        }

                                        _ => unreachable!("Not valid for globals"),

                                    };

                                    let ty = wasm_encoder::GlobalType {

                                        val_type: ty,

                                        mutable: *mutable,

                                        shared: *shared,

                                    };

                                    // Add to globals

                                    new_global_section.global(ty, &init);

                                }

                            }

                        }

                        let code_index = config.info().code;

                        let global_index = config.info().globals;

                        // This conditional placing enforces to write the global

                        // section by respecting its relative order in the Wasm module

                        let insert_globals_before = config

                            .info()

                            .globals

                            .or(config.info().exports)

                            .or(config.info().start)

                            .or(config.info().elements)

                            .or(config.info().data_count)

                            .or(code_index);

                        // If the mutator is in this staeg, then it passes the can_mutate filter,

                        // which checks for code section existence

                        let insert_globals_before = insert_globals_before.unwrap();

                        let module = config.info().replace_multiple_sections(

                            move |index, _sectionid, module: &mut wasm_encoder::Module| {

                                if insert_globals_before == index

                            // Write if needed or if it wasm in the init Wasm

                            && (new_global_section.len() > 0 || global_index.is_some() )

                                {

                                    // Insert the new globals here

                                    module.section(&new_global_section);

                                }

                                if index == code_index.unwrap() {

                                    // Replace code section

                                    module.section(&codes);

                                    return true;

                                }

                                if let Some(gidx) = global_index {

                                    // return true since the global section is written by the

                                    // conditional position writer

                                    return gidx == index;

                                }

                                // False to say the underlying encoder to write the preexisting

                                // section

                                false

                            },

                        );

                        Ok(module)

                    })

                    .map_while(|module: Result<Module>| match module {

                        Ok(module) => Some(Ok(module)),

                        Err(e) if matches!(e.kind(), ErrorKind::OutOfFuel) => None,

                        Err(e) => Some(Err(e)),

                    });

                return Ok(Box::new(iterator));

            }

            function_to_mutate = (function_to_mutate + 1) % function_count;

            visited_functions += 1;

        }

        fn copy_locals(reader: FunctionBody) -> Result<Function> {

            // Create the new function

            let mut localreader = reader.get_locals_reader()?;

            // Get current locals and map to encoder types

            let mut local_count = 0;

            let current_locals = (0..localreader.get_count())

                .map(|_| {

                    let (count, ty) = localreader.read().unwrap();

                    local_count += count;

                    (count, map_type(ty).unwrap())

                })

                .collect::<Vec<(u32, ValType)>>();

            Ok(Function::new(current_locals /*copy locals here*/))

        }

    }

    /// To separate the methods will allow us to test rule by rule

    fn mutate_with_rules<'a>(

        &self,

        config: &'a mut WasmMutate,

        rules: &[Rewrite<Lang, PeepholeMutationAnalysis>],

    ) -> Result<Box<dyn Iterator<Item = Result<Module>> + 'a>> {

        self.random_mutate(config, rules)

    }

}

/// Meta mutator for peephole

impl Mutator for PeepholeMutator {

    fn mutate<'a>(

        &self,

        config: &'a mut crate::WasmMutate,

    ) -> Result<Box<dyn Iterator<Item = Result<Module>> + 'a>> {

        let rules = match self.rules.clone() {

            Some(rules) => rules,

            // Calculate here type related information for parameters, locals and returns

            // This information could be passed to the conditions to check for type correctness rewriting

            // Write the new rules in the rules.rs file

            None => self.get_rules(config),

        };

        let modules = self.mutate_with_rules(config, &rules)?;

        Ok(modules)

    }

    fn can_mutate<'a>(&self, config: &'a WasmMutate) -> bool {

        config.info().has_code() && config.info().num_local_functions() > 0

    }

}

/// This macro is meant to be used for testing deep mutators

/// It receives the original wat text variable, the expression returning the mutated function and the expected wat

/// For an example, look at SwapCommutativeOperator

#[cfg(test)]

#[macro_export]

macro_rules! match_code_mutation {

    ($wat: ident, $mutation:expr, $expected:ident) => {{

        let original = &wat::parse_str($wat).unwrap();

        let mut parser = Parser::new(0);

        let config = WasmMutate::default();

        let mut offset = 0;

        let mut modu = Module::new();

        let mut codesection = CodeSection::new();

        loop {

            let (payload, chunksize) = match parser.parse(&original[offset..], true).unwrap() {

                Chunk::NeedMoreData(_) => {

                    panic!("This should not be reached");

                }

                Chunk::Parsed { consumed, payload } => (payload, consumed),

            };

            offset += chunksize;

            match payload {

                Payload::TypeSection(reader) => {

                    modu.section(&RawSection {

                        id: SectionId::Type.into(),

                        data: &original[reader.range().start..reader.range().end],

                    });

                }

                Payload::FunctionSection(reader) => {

                    modu.section(&RawSection {

                        id: SectionId::Function.into(),

                        data: &original[reader.range().start..reader.range().end],

                    });

                }

                Payload::ExportSection(reader) => {

                    modu.section(&RawSection {

                        id: SectionId::Export.into(),

                        data: &original[reader.range().start..reader.range().end],

                    });

                }

                Payload::CodeSectionEntry(reader) => {

                    let operatorsreader = reader.get_operators_reader().unwrap();

                    let range = operatorsreader.get_binary_reader().range();

                    let operators = operatorsreader

                        .into_iter_with_offsets()

                        .collect::<wasmparser::Result<Vec<OperatorAndByteOffset>>>()

                        .unwrap();

                    let mutated = $mutation(&config, operators, reader, range, original);

                    codesection.function(&mutated);

                }

                wasmparser::Payload::End => break,

                _ => {

                    // do nothing

                }

            }

        }

        modu.section(&codesection);

        let mutated = modu.finish();

        crate::validate(&mutated);

        let text = wasmprinter::print_bytes(mutated).unwrap();

        // parse expected to use the same formatter

        let expected_bytes = &wat::parse_str($expected).unwrap();

        let expectedtext = wasmprinter::print_bytes(expected_bytes).unwrap();

        assert_eq!(text, expectedtext);

    }};

}

#[cfg(test)]

mod tests {

    use crate::{

        WasmMutate,

        info::ModuleInfo,

        module::PrimitiveTypeInfo,

        mutators::{Mutator, peephole::PeepholeMutator},

    };

    use egg::{Id, Rewrite, Subst, rewrite};

    use rand::{SeedableRng, rngs::SmallRng};

    use super::{EG, PeepholeMutationAnalysis};

    use crate::mutators::peephole::Lang;

    /// Condition to apply the unfold operator

    /// check that the var is a constant

    #[allow(dead_code)]

    fn is_const(vari: &'static str) -> impl Fn(&mut EG, Id, &Subst) -> bool {

        move |egraph: &mut EG, _, subst| {

            let var = vari.parse();

            match var {

                Ok(var) => {

                    let eclass = &egraph[subst[var]];

                    if eclass.nodes.len() == 1 {

                        let node = &eclass.nodes[0];

                        match node {

                            Lang::I32(_) => true,

                            Lang::I64(_) => true,

                            _ => false,

                        }

                    } else {

                        false

                    }

                }

                Err(_) => false,

            }

        }

    }

    fn is_type(vari: &'static str, t: PrimitiveTypeInfo) -> impl Fn(&mut EG, Id, &Subst) -> bool {

        move |egraph: &mut EG, _, subst| {

            let var = vari.parse();

            match var {

                Ok(var) => {

                    let eclass = &egraph[subst[var]];

                    match &eclass.data {

                        Some(d) => d.tpe == t,

                        None => false,

                    }

                }

                Err(_) => false,

            }

        }

    }

    // Random numbers vary by pointer-width presumably due to `usize` at some

    // point factoring in, and this test is only known to pass within a

    // reasonable amount of time on 64-bit platforms.

    #[test]

    #[cfg(target_pointer_width = "64")]

    fn test_peep_unfold2() {

        let rules: &[Rewrite<super::Lang, PeepholeMutationAnalysis>] = &[

            rewrite!("unfold-2";  "?x" => "(i32.unfold ?x)" if is_const("?x") if is_type("?x", PrimitiveTypeInfo::I32)),

        ];

        test_peephole_mutator(

            r#"

            (module

                (func (export "exported_func") (result i32) (local i32 i32)

                    i32.const 56

                )

            )

            "#,

            rules,

            r#"

            (module

                (type (;0;) (func (result i32)))

                (func (;0;) (type 0) (result i32)

                  (local i32 i32)

                  i32.const 1731343737

                  i32.const -1731343681

                  i32.add)

                (export "exported_func" (func 0)))

            "#,

            0,

        );

    }

    #[test]

    fn test_peep_stack_neutral2() {

        let rules: &[Rewrite<super::Lang, PeepholeMutationAnalysis>] = &[

            rewrite!("strength-undo";  "?x" => "(i32.or ?x ?x)" if is_type("?x", PrimitiveTypeInfo::I32)),

        ];

        test_peephole_mutator(

            r#"

        (module

            (func (export "exported_func")  (local i32 i32)

                i32.const 10

                drop

            )

        )

        "#,

            rules,

            r#"

            (module

                (type (;0;) (func ))

                (func (;0;) (type 0)

                    (local i32 i32)

                    i32.const 10

                    i32.const 10

                    i32.or

                    drop

                )

                (export "exported_func" (func 0)))

            "#,

            4,

        );

    }

    #[test]

    fn test_peep_select() {

        let rules: &[Rewrite<super::Lang, PeepholeMutationAnalysis>] =

            &[rewrite!("rule";  "(select ?x ?y ?z)" => "(select ?y ?x (i32.eqz ?z))")];

        test_peephole_mutator(

            r#"

        (module

            (func (export "exported_func") (result f32)  (local i32 i32)

                f32.const 10

                f32.const 20

                f32.add

                f32.const 200

                local.get 0

                select

            )

        )

        "#,

            rules,

            r#"

            (module

                (type (;0;) (func (result f32)))

                (func (;0;) (type 0) (result f32)

                  (local i32 i32)

                  f32.const 0x1.9p+7 (;=200;)

                  f32.const 0x1.4p+3 (;=10;)

                  f32.const 0x1.4p+4 (;=20;)

                  f32.add

                  local.get 0

                  i32.eqz

                  select)

                (export "exported_func" (func 0)))

            "#,

            4,

        );

    }

    #[test]

    fn test_peep_wrap() {

        let rules: &[Rewrite<super::Lang, PeepholeMutationAnalysis>] = &[

            rewrite!("strength-undo";  "?x" => "(i32.add ?x i32.const.0)" if is_type("?x", PrimitiveTypeInfo::I32)),

        ];

        test_peephole_mutator(

            r#"

        (module

            (func (export "exported_func") (result i32) (local i64)

                local.get 0

                i64.const 0

                i64.shl

                i32.wrap_i64

                i32.const -441701230

                i32.const 441701230

                i32.add

                i32.add

            )

        )

        "#,

            rules,

            r#"

        (module

            (func (export "exported_func") (result i32) (local i64)

                local.get 0

                i64.const 0

                i64.shl

                i32.wrap_i64

                i32.const -441701230

                i32.const 0

                i32.add

                i32.const 441701230

                i32.add

                i32.add

            )

        )

        "#,

            0,

        );

    }

    #[test]

    fn test_peep_irelop1() {

        let rules: &[Rewrite<super::Lang, PeepholeMutationAnalysis>] =

            &[rewrite!("strength-undo";  "(i64.eqz ?x)" => "(i64.eq ?x i64.const.0)")];

        test_peephole_mutator(

            r#"

        (module

            (func (export "exported_func") (result i32) (local i32 i32)

                i64.const 10

                i64.eqz

            )

        )

        "#,

            rules,

            r#"

            (module

                (type (;0;) (func (result i32) ))

                (func (;0;) (type 0)

                    (local i32 i32)

                    i64.const 10

                    i64.const 0

                    i64.eq

                )

                (export "exported_func" (func 0)))

            "#,

            2,

        );

    }

    #[test]

    fn test_peep_bug1() {

        let rules: &[Rewrite<super::Lang, PeepholeMutationAnalysis>] = &[

            rewrite!("strength-undo";  "?x" => "(i32.shl ?x i32.const.0)" if is_type("?x", PrimitiveTypeInfo::I32)),

        ];

        test_peephole_mutator(

            r#"

            (module

                (type (;0;) (func (result i32)))

                (func (;0;) (type 0) (result i32)

                  i32.const -14671840

                  i64.extend_i32_u

                  i32.const -1

                  i64.extend_i32_u

                  i64.rem_s

                  i64.const -1

                  i64.le_u)

                (data (;0;) ""))

        "#,

            rules,

            r#"

            (module

                (type (;0;) (func (result i32)))

                (func (;0;) (type 0) (result i32)

                  i32.const -14671840

                  i64.extend_i32_u

                  i32.const -1

                  i64.extend_i32_u

                  i64.rem_s

                  i64.const -1

                  i64.le_u

                  i32.const 0

                  i32.shl)

                (data (;0;) ""))

            "#,

            11494877297919394048,

        );

    }

    #[test]

    fn test_peep_commutative() {

        let rules: &[Rewrite<super::Lang, PeepholeMutationAnalysis>] =

            &[rewrite!("commutative-1";  "(i32.add ?x ?y)" => "(i32.add ?y ?x)")];

        test_peephole_mutator(

            r#"

        (module

            (func (export "exported_func") (result i32) (local i32 i32)

                i32.const 42

                i32.const 1

                i32.add

            )

        )

        "#,

            rules,

            r#"

            (module

                (type (;0;) (func (result i32)))

                (func (;0;) (type 0) (result i32)

                  (local i32 i32)

                  i32.const 1

                  i32.const 42

                  i32.add

                )

                (export "exported_func" (func 0)))

            "#,

            6,

        );

    }

    #[test]

    fn test_peep_inversion() {

        let rules: &[Rewrite<super::Lang, PeepholeMutationAnalysis>] =

            &[rewrite!("inversion-1";  "(i32.gt_s ?x ?y)" => "(i32.le_s ?y ?x)")];

        test_peephole_mutator(

            r#"

        (module

            (func (export "exported_func") (result i32) (local i32 i32)

                i32.const 42

                i32.const 1

                i32.gt_s

            )

        )

        "#,

            rules,

            r#"

            (module

                (type (;0;) (func (result i32)))

                (func (;0;) (type 0) (result i32)

                  (local i32 i32)

                  i32.const 1

                  i32.const 42

                  i32.le_s)

                (export "exported_func" (func 0)))

            "#,

            0,

        );

    }

    #[test]

    fn test_peep_integrtion() {

        let rules: &[Rewrite<super::Lang, PeepholeMutationAnalysis>] =

            &[rewrite!("inversion-1";  "(i32.gt_s ?x ?y)" => "(i32.le_s ?y ?x)")];

        test_peephole_mutator(

            r#"

        (module

            (func (export "exported_func") (result i32) (local i32 i32)

                i32.const 42

                i32.const 1

                i32.gt_s

            )

        )

        "#,

            rules,

            r#"

            (module

                (type (;0;) (func (result i32)))

                (func (;0;) (type 0) (result i32)

                  (local i32 i32)

                  i32.const 1

                  i32.const 42

                  i32.le_s)

                (export "exported_func" (func 0)))

            "#,

            0,

        );

    }

    #[test]

    fn test_peep_inversion2() {

        let original = r#"

            (module

                (type (;0;) (func (param i64 i32 f32)))

                (func (;0;) (type 0) (param i64 i32 f32)

                i32.const 100

                i32.const 200

                i32.store offset=600 align=1

                )

                (memory (;0;) 0)

                (export "\00" (memory 0)))

        "#;

        let original = &wat::parse_str(original).unwrap();

        let info = ModuleInfo::new(original).unwrap();

        let mut wasmmutate = WasmMutate::default();

        wasmmutate.fuel(3);

        wasmmutate.info = Some(info);

        let rnd = SmallRng::seed_from_u64(0);

        wasmmutate.rng = Some(rnd);

        let mutator = PeepholeMutator::new(2);

        let can_mutate = mutator.can_mutate(&wasmmutate);

        assert_eq!(can_mutate, true);

        let rules = mutator.get_rules(&wasmmutate);

        for mutated in mutator.mutate_with_rules(&mut wasmmutate, &rules).unwrap() {

            let module = mutated.unwrap();

            let mutated_bytes = &module.finish();

            let _text = wasmprinter::print_bytes(mutated_bytes).unwrap();

            crate::validate(mutated_bytes);

        }

    }

    #[test]

    fn test_mem_store1() {

        let rules: &[Rewrite<super::Lang, PeepholeMutationAnalysis>] = &[

            rewrite!("rule";  "(i32.store.600.0.0 ?value ?offset)" => "(i32.store.0.0.0 ?value (i32.add ?offset i32.const.600))" ),

        ];

        test_peephole_mutator(

            r#"

            (module

                (type (;0;) (func (param i64 i32 f32)))

                (func (;0;) (type 0) (param i64 i32 f32)

                  i32.const 100

                  i32.const 200

                  i32.store offset=600 align=1

                )

                (memory (;0;) 0)

                (export "\00" (memory 0)))

        "#,

            rules,

            r#"

            (module

                (type (;0;) (func (param i64 i32 f32)))

                (func (;0;) (type 0) (param i64 i32 f32)

                  i32.const 100

                  i32.const 200

                  i32.const 600

                  i32.add

                  i32.store align=1)

                (memory (;0;) 0)

                (export "\00" (memory 0)))

            "#,

            0,

        );

    }

    #[test]

    fn test_peep_shl0() {

        let rules: &[Rewrite<super::Lang, PeepholeMutationAnalysis>] = &[

            rewrite!("strength-undo3";  "(i64.shr_u ?x ?y)" => "(i64.shl (i64.shr_u ?x ?y) i64.const.0)" ),

        ];

        test_peephole_mutator(

            r#"

            (module

                (type (;0;) (func (param i64 i32 f32)))

                (func (;0;) (type 0) (param i64 i32 f32)

                  i64.const 89

                  local.get 1

                  i64.load align=2

                  local.get 1

                  i64.load align=1

                  i64.shr_u

                  drop

                  drop

                )

                (memory (;0;) 0)

                (export "\00" (memory 0)))

        "#,

            rules,

            r#"

            (module

                (type (;0;) (func (param i64 i32 f32)))

                (func (;0;) (type 0) (param i64 i32 f32)

                  i64.const 89

                  local.get 1

                  i64.load align=2

                  local.get 1

                  i64.load align=1

                  i64.shr_u

                  i64.const 0

                  i64.shl

                  drop

                  drop)

                (memory (;0;) 0)

                (export "\00" (memory 0)))

            "#,

            5,

        );

    }

    #[test]

    fn test_peep_idem1() {

        let rules: &[Rewrite<super::Lang, PeepholeMutationAnalysis>] = &[

            rewrite!("idempotent-1";  "?x" => "(i32.or ?x ?x)" if is_type("?x", PrimitiveTypeInfo::I32)),

            rewrite!("idempotent-12";  "?x" => "(i64.or ?x ?x)" if is_type("?x", PrimitiveTypeInfo::I64)),

        ];

        test_peephole_mutator(

            r#"

        (module

            (func (export "exported_func") (result i32) (local i32 i32)

                i32.const 56

            )

        )

        "#,

            rules,

            r#"

        (module

            (type (;0;) (func (result i32)))

            (func (;0;) (type 0) (result i32)

                (local i32 i32)

                i32.const 56

                i32.const 56

                i32.or)

            (export "exported_func" (func 0)))

        "#,

            0,

        );

    }

    #[test]

    fn test_peep_cv() {

        let rules: &[Rewrite<super::Lang, PeepholeMutationAnalysis>] = &[

            rewrite!("idempotent-1";  "?x" => "(i32.or ?x ?x)" if is_type("?x", PrimitiveTypeInfo::I32)),

        ];

        test_peephole_mutator(

            r#"

        (module

            (func (export "exported_func") (result i32) (local i32 i32)

                i64.const 56

                i64.const 2

                i64.mul

                i32.wrap_i64

            )

        )

        "#,

            rules,

            r#"

        (module

            (type (;0;) (func (result i32)))

            (func (;0;) (type 0) (result i32)

                (local i32 i32)

                i64.const 56

                i64.const 2

                i64.mul

                i32.wrap_i64

                i64.const 56

                i64.const 2

                i64.mul

                i32.wrap_i64

                i32.or)

            (export "exported_func" (func 0)))

        "#,

            4,

        );

    }

    #[test]

    fn test_peep_cv4() {

        let rules: &[Rewrite<super::Lang, PeepholeMutationAnalysis>] = &[

            rewrite!("idempotent-1";  "?x" => "(i32.or ?x ?x)" if is_type("?x", PrimitiveTypeInfo::I32)),

        ];

        test_peephole_mutator(

            r#"

        (module

            (func (export "exported_func") (result i32) (local i32 i32)

                i32.const 56

                i32.extend8_s

            )

        )

        "#,

            rules,

            r#"

        (module

            (func (;0;) (result i32)

                (local i32 i32)

                i32.const 56

                i32.extend8_s

                i32.const 56

                i32.extend8_s

                i32.or)

            (export "exported_func" (func 0)))

        "#,

            8,

        );

    }

    #[test]

    fn test_peep_cv5() {