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ZoKrates/zokrates_analysis/src/propagation.rs

2207 lines
94 KiB
Rust

//! Module containing constant propagation for the typed AST
//!
//! Constant propagation on the SSA program. The constants map can be passed by the caller to allow for many passes to use
//! the same constants.
//!
//! @file propagation.rs
//! @author Thibaut Schaeffer <thibaut@schaeff.fr>
//! @date 2018
use num::traits::Pow;
use num_bigint::BigUint;
use std::collections::HashMap;
use std::convert::{TryFrom, TryInto};
use std::fmt;
use std::ops::*;
use std::ops::{BitAnd, BitOr, BitXor, Shl, Shr, Sub};
use zokrates_ast::common::expressions::{
BinaryExpression, BinaryOrExpression, EqExpression, ValueExpression,
};
use zokrates_ast::common::operators::OpEq;
use zokrates_ast::common::{FlatEmbed, ResultFold, WithSpan};
use zokrates_ast::typed::result_folder::*;
use zokrates_ast::typed::types::Type;
use zokrates_ast::typed::*;
use zokrates_field::Field;
pub type Constants<'ast, T> = HashMap<Identifier<'ast>, TypedExpression<'ast, T>>;
#[derive(Debug, PartialEq, Eq)]
pub enum Error {
Type(String),
AssertionFailed(RuntimeError),
InvalidValue(String),
OutOfBounds(u128, u128),
VariableLength(String),
}
impl fmt::Display for Error {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match self {
Error::Type(s) => write!(f, "{}", s),
Error::AssertionFailed(err) => write!(f, "Assertion failed ({})", err),
Error::InvalidValue(s) => write!(f, "{}", s),
Error::OutOfBounds(index, size) => write!(
f,
"Out of bounds index ({} >= {}) found during static analysis",
index, size
),
Error::VariableLength(message) => write!(f, "{}", message),
}
}
}
#[derive(Debug, Default)]
pub struct Propagator<'ast, T> {
// constants keeps track of constant expressions
// we currently do not support partially constant expressions: `field [x, 1][1]` is not considered constant, `field [0, 1][1]` is
constants: Constants<'ast, T>,
}
impl<'ast, T: Field> Propagator<'ast, T> {
pub fn propagate(p: TypedProgram<'ast, T>) -> Result<TypedProgram<'ast, T>, Error> {
Propagator::default().fold_program(p)
}
pub fn clear_call_frame(&mut self, frame: usize) {
self.constants.retain(|id, _| id.id.frame != frame);
}
// get a mutable reference to the constant corresponding to a given assignee if any, otherwise
// return the identifier at the root of this assignee
fn try_get_constant_mut<'b>(
&mut self,
assignee: &'b TypedAssignee<'ast, T>,
) -> Result<(&'b Variable<'ast, T>, &mut TypedExpression<'ast, T>), &'b Variable<'ast, T>> {
match assignee {
TypedAssignee::Identifier(var) => self
.constants
.get_mut(&var.id)
.map(|c| Ok((var, c)))
.unwrap_or(Err(var)),
TypedAssignee::Select(assignee, index) => match self.try_get_constant_mut(assignee) {
Ok((variable, constant)) => match index.as_inner() {
UExpressionInner::Value(n) => match constant {
TypedExpression::Array(a) => match a.as_inner_mut() {
ArrayExpressionInner::Value(value) => {
match value.value.get_mut(n.value as usize) {
Some(TypedExpressionOrSpread::Expression(ref mut e)) => {
Ok((variable, e))
}
None => Err(variable),
_ => unreachable!(),
}
}
_ => unreachable!("should be an array value"),
},
_ => unreachable!("should be an array expression"),
},
_ => Err(variable),
},
e => e,
},
TypedAssignee::Member(assignee, m) => match self.try_get_constant_mut(assignee) {
Ok((v, c)) => {
let ty = assignee.get_type();
let index = match ty {
Type::Struct(struct_ty) => struct_ty
.members
.iter()
.position(|member| *m == member.id)
.unwrap(),
_ => unreachable!("should be a struct type"),
};
match c {
TypedExpression::Struct(a) => match a.as_inner_mut() {
StructExpressionInner::Value(value) => Ok((v, &mut value.value[index])),
_ => unreachable!("should be a struct value"),
},
_ => unreachable!("should be a struct expression"),
}
}
e => e,
},
TypedAssignee::Element(assignee, index) => match self.try_get_constant_mut(assignee) {
Ok((v, c)) => match c {
TypedExpression::Tuple(a) => match a.as_inner_mut() {
TupleExpressionInner::Value(value) => {
Ok((v, &mut value.value[*index as usize]))
}
_ => unreachable!("should be a tuple value"),
},
_ => unreachable!("should be a tuple expression"),
},
e => e,
},
}
}
}
impl<'ast, T: Field> ResultFolder<'ast, T> for Propagator<'ast, T> {
type Error = Error;
fn fold_program(&mut self, p: TypedProgram<'ast, T>) -> Result<TypedProgram<'ast, T>, Error> {
let main = p.main.clone();
Ok(TypedProgram {
modules: p
.modules
.into_iter()
.map(|(module_id, module)| {
if module_id == main {
self.fold_module(module).map(|m| (module_id, m))
} else {
Ok((module_id, module))
}
})
.collect::<Result<_, _>>()?,
..p
})
}
fn fold_function_symbol_declaration(
&mut self,
s: TypedFunctionSymbolDeclaration<'ast, T>,
) -> Result<TypedFunctionSymbolDeclaration<'ast, T>, Error> {
if s.key.id == "main" {
let key = s.key;
self.fold_function_symbol(s.symbol)
.map(|f| TypedFunctionSymbolDeclaration { key, symbol: f })
} else {
Ok(s)
}
}
fn fold_conditional_expression<
E: Expr<'ast, T> + Conditional<'ast, T> + PartialEq + ResultFold<Self, Self::Error>,
>(
&mut self,
_: &E::Ty,
e: ConditionalExpression<'ast, T, E>,
) -> Result<ConditionalOrExpression<'ast, T, E>, Self::Error> {
Ok(match self.fold_boolean_expression(*e.condition)? {
BooleanExpression::Value(v) if v.value => {
ConditionalOrExpression::Expression(e.consequence.fold(self)?.into_inner())
}
BooleanExpression::Value(v) if !v.value => {
ConditionalOrExpression::Expression(e.alternative.fold(self)?.into_inner())
}
condition => match (e.consequence.fold(self)?, e.alternative.fold(self)?) {
(consequence, alternative) if consequence == alternative => {
ConditionalOrExpression::Expression(consequence.into_inner())
}
(consequence, alternative) => ConditionalOrExpression::Conditional(
ConditionalExpression::new(condition, consequence, alternative, e.kind),
),
},
})
}
fn fold_assembly_assignment(
&mut self,
s: AssemblyAssignment<'ast, T>,
) -> Result<Vec<TypedAssemblyStatement<'ast, T>>, Self::Error> {
let assignee = self.fold_assignee(s.assignee)?;
let expr = self.fold_expression(s.expression)?;
if expr.is_constant() {
match assignee {
TypedAssignee::Identifier(var) => {
let expr = expr.into_canonical_constant();
assert!(self.constants.insert(var.id, expr).is_none());
Ok(vec![])
}
assignee => match self.try_get_constant_mut(&assignee) {
Ok((_, c)) => {
*c = expr.into_canonical_constant();
Ok(vec![])
}
Err(v) => match self.constants.remove(&v.id) {
// invalidate the cache for this identifier, and define the latest
// version of the constant in the program, if any
Some(c) => Ok(vec![
TypedAssemblyStatement::assignment(v.clone().into(), c),
TypedAssemblyStatement::assignment(assignee, expr),
]),
None => Ok(vec![TypedAssemblyStatement::assignment(assignee, expr)]),
},
},
}
} else {
// the expression being assigned is not constant, invalidate the cache
let v = self
.try_get_constant_mut(&assignee)
.map(|(v, _)| v)
.unwrap_or_else(|v| v);
match self.constants.remove(&v.id) {
Some(c) => Ok(vec![
TypedAssemblyStatement::assignment(v.clone().into(), c),
TypedAssemblyStatement::assignment(assignee, expr),
]),
None => Ok(vec![TypedAssemblyStatement::assignment(assignee, expr)]),
}
}
}
fn fold_assembly_constraint(
&mut self,
s: AssemblyConstraint<'ast, T>,
) -> Result<Vec<TypedAssemblyStatement<'ast, T>>, Self::Error> {
let span = s.get_span();
let left = self.fold_field_expression(s.left)?;
let right = self.fold_field_expression(s.right)?;
// a bit hacky, but we use a fake boolean expression to check this
let is_equal = BooleanExpression::field_eq(left.clone(), right.clone()).span(span);
let is_equal = self.fold_boolean_expression(is_equal)?;
match is_equal {
BooleanExpression::Value(v) if v.value => Ok(vec![]),
BooleanExpression::Value(v) if !v.value => {
Err(Error::AssertionFailed(RuntimeError::SourceAssertion(
s.metadata
.message(Some(format!("In asm block: `{} !== {}`", left, right))),
)))
}
_ => Ok(vec![TypedAssemblyStatement::constraint(
left, right, s.metadata,
)]),
}
}
fn fold_definition_statement(
&mut self,
s: DefinitionStatement<'ast, T>,
) -> Result<Vec<TypedStatement<'ast, T>>, Self::Error> {
let span = s.get_span();
match s.rhs {
// propagation to the defined variable if rhs is a constant
DefinitionRhs::Expression(e) => {
let assignee = self.fold_assignee(s.assignee)?;
let expr = self.fold_expression(e)?;
if let (Ok(a), Ok(e)) = (
ConcreteType::try_from(assignee.get_type()),
ConcreteType::try_from(expr.get_type()),
) {
if a != e {
return Err(Error::Type(format!(
"Cannot assign {} of type {} to {} of type {}",
expr, e, assignee, a
)));
}
};
if expr.is_constant() {
match assignee {
TypedAssignee::Identifier(var) => {
let expr = expr.into_canonical_constant();
assert!(self.constants.insert(var.id, expr).is_none());
Ok(vec![])
}
assignee => match self.try_get_constant_mut(&assignee) {
Ok((_, c)) => {
*c = expr.into_canonical_constant();
Ok(vec![])
}
Err(v) => match self.constants.remove(&v.id) {
// invalidate the cache for this identifier, and define the latest
// version of the constant in the program, if any
Some(c) => Ok(vec![
TypedStatement::definition(v.clone().into(), c),
TypedStatement::definition(assignee, expr),
]),
None => Ok(vec![TypedStatement::definition(assignee, expr)]),
},
},
}
} else {
// the expression being assigned is not constant, invalidate the cache
let v = self
.try_get_constant_mut(&assignee)
.map(|(v, _)| v)
.unwrap_or_else(|v| v);
match self.constants.remove(&v.id) {
Some(c) => Ok(vec![
TypedStatement::definition(v.clone().into(), c),
TypedStatement::definition(assignee, expr),
]),
None => Ok(vec![TypedStatement::definition(assignee, expr)]),
}
}
}
DefinitionRhs::EmbedCall(e) => {
let assignee = self.fold_assignee(s.assignee)?;
let embed_call = self.fold_embed_call(e)?;
fn process_u_from_bits<'ast, T: Field>(
arguments: &[TypedExpression<'ast, T>],
bitwidth: UBitwidth,
) -> TypedExpression<'ast, T> {
assert_eq!(arguments.len(), 1);
let argument = arguments.last().cloned().unwrap();
let argument = argument.into_canonical_constant();
match ArrayExpression::try_from(argument)
.unwrap()
.into_inner()
{
ArrayExpressionInner::Value(v) =>
UExpression::value(
v.into_iter()
.map(|v| match v {
TypedExpressionOrSpread::Expression(
TypedExpression::Boolean(
BooleanExpression::Value(v),
),
) => v,
_ => unreachable!("Should be a constant boolean expression. Spreads are not expected here, as in their presence the argument isn't constant"),
})
.enumerate()
.fold(0, |acc, (i, v)| {
if v.value {
acc + 2u128.pow(
(bitwidth.to_usize() - i - 1)
.try_into()
.unwrap(),
)
} else {
acc
}
}),
)
.annotate(bitwidth)
.into(),
_ => unreachable!("should be an array value"),
}
}
fn process_u_to_bits<'ast, T: Field>(
arguments: &[TypedExpression<'ast, T>],
bitwidth: UBitwidth,
) -> TypedExpression<'ast, T> {
assert_eq!(arguments.len(), 1);
match UExpression::try_from(arguments[0].clone())
.unwrap()
.into_inner()
{
UExpressionInner::Value(v) => {
let mut num = v.value;
let mut res = vec![];
for i in (0..bitwidth as u32).rev() {
if 2u128.pow(i) <= num {
num -= 2u128.pow(i);
res.push(true);
} else {
res.push(false);
}
}
assert_eq!(num, 0);
ArrayExpression::value(
res.into_iter()
.map(|v| BooleanExpression::value(v).into())
.collect::<Vec<_>>(),
)
.annotate(ArrayType::new(Type::Boolean, bitwidth.to_usize() as u32))
.into()
}
_ => unreachable!("should be a uint value"),
}
}
match embed_call.arguments.iter().all(|a| a.is_constant()) {
true => {
let r: Option<TypedExpression<'ast, T>> = match embed_call.embed {
FlatEmbed::BitArrayLe => Ok(None), // todo
FlatEmbed::FieldToBoolUnsafe => {
match FieldElementExpression::try_from_typed(
embed_call.arguments[0].clone(),
) {
Ok(FieldElementExpression::Value(n))
if n.value == T::from(0) =>
{
Ok(Some(BooleanExpression::value(false).span(span).into()))
}
Ok(FieldElementExpression::Value(n))
if n.value == T::from(1) =>
{
Ok(Some(BooleanExpression::value(true).span(span).into()))
}
Ok(FieldElementExpression::Value(n)) => {
Err(Error::InvalidValue(format!(
"Cannot call `{}` with value `{}`: should be 0 or 1",
embed_call.embed.id(),
n
)))
}
_ => Ok(None),
}
}
FlatEmbed::U64FromBits => Ok(Some(process_u_from_bits(
&embed_call.arguments,
UBitwidth::B64,
))),
FlatEmbed::U32FromBits => Ok(Some(process_u_from_bits(
&embed_call.arguments,
UBitwidth::B32,
))),
FlatEmbed::U16FromBits => Ok(Some(process_u_from_bits(
&embed_call.arguments,
UBitwidth::B16,
))),
FlatEmbed::U8FromBits => Ok(Some(process_u_from_bits(
&embed_call.arguments,
UBitwidth::B8,
))),
FlatEmbed::U64ToBits => Ok(Some(process_u_to_bits(
&embed_call.arguments,
UBitwidth::B64,
))),
FlatEmbed::U32ToBits => Ok(Some(process_u_to_bits(
&embed_call.arguments,
UBitwidth::B32,
))),
FlatEmbed::U16ToBits => Ok(Some(process_u_to_bits(
&embed_call.arguments,
UBitwidth::B16,
))),
FlatEmbed::U8ToBits => Ok(Some(process_u_to_bits(
&embed_call.arguments,
UBitwidth::B8,
))),
FlatEmbed::Unpack => {
assert_eq!(embed_call.arguments.len(), 1);
assert_eq!(embed_call.generics.len(), 1);
let bit_width = embed_call.generics[0];
match FieldElementExpression::<T>::try_from(
embed_call.arguments[0].clone(),
)
.unwrap()
{
FieldElementExpression::Value(num) => {
let mut acc = num.value;
let mut res = vec![];
for i in (0..bit_width as usize).rev() {
if T::from(2).pow(i) <= acc {
acc = acc - T::from(2).pow(i);
res.push(true);
} else {
res.push(false);
}
}
if acc != T::zero() {
Err(Error::InvalidValue(format!(
"Cannot unpack `{}` to `{}`: value is too large",
num,
assignee.get_type()
)))
} else {
Ok(Some(
ArrayExpression::value(
res.into_iter()
.map(|v| {
BooleanExpression::value(v)
.span(span)
.into()
})
.collect::<Vec<_>>(),
)
.annotate(ArrayType::new(Type::Boolean, bit_width))
.span(span)
.into(),
))
}
}
_ => unreachable!("should be a field value"),
}
}
#[cfg(feature = "bellman")]
FlatEmbed::Sha256Round => Ok(None),
#[cfg(feature = "ark")]
FlatEmbed::SnarkVerifyBls12377 => Ok(None),
}?;
Ok(match r {
// if the function call returns a constant
Some(expr) => match assignee {
TypedAssignee::Identifier(var) => {
self.constants.insert(var.id, expr);
vec![]
}
assignee => match self.try_get_constant_mut(&assignee) {
Ok((_, c)) => {
*c = expr;
vec![]
}
Err(v) => match self.constants.remove(&v.id) {
Some(c) => vec![
TypedStatement::definition(v.clone().into(), c),
TypedStatement::definition(assignee, expr),
],
None => {
vec![TypedStatement::definition(assignee, expr)]
}
},
},
},
None => {
// if the function call does not return a constant, invalidate the cache
// this happens because we only propagate certain calls here
let v = self
.try_get_constant_mut(&assignee)
.map(|(v, _)| v)
.unwrap_or_else(|v| v);
match self.constants.remove(&v.id) {
Some(c) => vec![
TypedStatement::definition(v.clone().into(), c),
TypedStatement::embed_call_definition(assignee, embed_call),
],
None => vec![TypedStatement::embed_call_definition(
assignee, embed_call,
)],
}
}
})
}
false => {
// if the function arguments are not constant, invalidate the cache
// for the return assignees
let def =
TypedStatement::embed_call_definition(assignee.clone(), embed_call);
let v = self
.try_get_constant_mut(&assignee)
.map(|(v, _)| v)
.unwrap_or_else(|v| v);
Ok(match self.constants.remove(&v.id) {
Some(c) => {
vec![TypedStatement::definition(v.clone().into(), c), def]
}
None => vec![def],
})
}
}
}
}
}
fn fold_assembly_block(
&mut self,
s: AssemblyBlockStatement<'ast, T>,
) -> Result<Vec<TypedStatement<'ast, T>>, Self::Error> {
Ok(fold_assembly_block(self, s)?
.into_iter()
.filter(|s| match s {
TypedStatement::Assembly(s) => !s.inner.is_empty(),
_ => true,
})
.collect())
}
fn fold_for_statement(
&mut self,
s: ForStatement<'ast, T>,
) -> Result<Vec<TypedStatement<'ast, T>>, Self::Error> {
// we do not visit the for-loop statements
let from = self.fold_uint_expression(s.from)?;
let to = self.fold_uint_expression(s.to)?;
Ok(vec![TypedStatement::for_(s.var, from, to, s.statements)])
}
fn fold_assertion_statement(
&mut self,
s: AssertionStatement<'ast, T>,
) -> Result<Vec<TypedStatement<'ast, T>>, Self::Error> {
let _e_str = s.expression.to_string();
let expr = self.fold_boolean_expression(s.expression)?;
match expr {
BooleanExpression::Value(v) if !v.value => Err(Error::AssertionFailed(s.error)),
BooleanExpression::Value(v) if v.value => Ok(vec![]),
_ => Ok(vec![TypedStatement::assertion(expr, s.error)]),
}
}
fn fold_uint_expression_cases(
&mut self,
bitwidth: UBitwidth,
e: UExpressionInner<'ast, T>,
) -> Result<UExpressionInner<'ast, T>, Error> {
match e {
UExpressionInner::Add(e) => match (
self.fold_uint_expression(*e.left)?.into_inner(),
self.fold_uint_expression(*e.right)?.into_inner(),
) {
(UExpressionInner::Value(v1), UExpressionInner::Value(v2)) => {
Ok(UExpression::value(
(v1.value + v2.value) % 2_u128.pow(bitwidth.to_usize().try_into().unwrap()),
))
}
(e, UExpressionInner::Value(v)) | (UExpressionInner::Value(v), e) => {
match v.value {
0 => Ok(e),
_ => Ok(UExpression::add(
e.annotate(bitwidth),
UExpression::value(v.value).annotate(bitwidth),
)
.into_inner()),
}
}
(e1, e2) => {
Ok(UExpression::add(e1.annotate(bitwidth), e2.annotate(bitwidth)).into_inner())
}
},
UExpressionInner::Sub(e) => match (
self.fold_uint_expression(*e.left)?.into_inner(),
self.fold_uint_expression(*e.right)?.into_inner(),
) {
(UExpressionInner::Value(v1), UExpressionInner::Value(v2)) => {
Ok(UExpression::value(
(v1.value.wrapping_sub(v2.value))
% 2_u128.pow(bitwidth.to_usize().try_into().unwrap()),
))
}
(e, UExpressionInner::Value(v)) => match v.value {
0 => Ok(e),
_ => Ok(UExpression::sub(
e.annotate(bitwidth),
UExpressionInner::Value(v).annotate(bitwidth),
)
.into_inner()),
},
(e1, e2) => {
Ok(UExpression::sub(e1.annotate(bitwidth), e2.annotate(bitwidth)).into_inner())
}
},
UExpressionInner::FloorSub(e) => match (
self.fold_uint_expression(*e.left)?.into_inner(),
self.fold_uint_expression(*e.right)?.into_inner(),
) {
(UExpressionInner::Value(v1), UExpressionInner::Value(v2)) => {
Ok(UExpression::value(
v1.value.saturating_sub(v2.value)
% 2_u128.pow(bitwidth.to_usize().try_into().unwrap()),
))
}
(e, UExpressionInner::Value(v)) => match v.value {
0 => Ok(e),
_ => Ok(UExpression::floor_sub(
e.annotate(bitwidth),
UExpressionInner::Value(v).annotate(bitwidth),
)
.into_inner()),
},
(e1, e2) => {
Ok(UExpression::sub(e1.annotate(bitwidth), e2.annotate(bitwidth)).into_inner())
}
},
UExpressionInner::Mult(e) => match (
self.fold_uint_expression(*e.left)?.into_inner(),
self.fold_uint_expression(*e.right)?.into_inner(),
) {
(UExpressionInner::Value(v1), UExpressionInner::Value(v2)) => {
Ok(UExpression::value(
(v1.value * v2.value) % 2_u128.pow(bitwidth.to_usize().try_into().unwrap()),
))
}
(e, UExpressionInner::Value(v)) | (UExpressionInner::Value(v), e) => {
match v.value {
0 => Ok(UExpression::value(0)),
1 => Ok(e),
_ => Ok(UExpression::mul(
e.annotate(bitwidth),
UExpressionInner::Value(v).annotate(bitwidth),
)
.into_inner()),
}
}
(e1, e2) => {
Ok(UExpression::mul(e1.annotate(bitwidth), e2.annotate(bitwidth)).into_inner())
}
},
UExpressionInner::Div(e) => match (
self.fold_uint_expression(*e.left)?.into_inner(),
self.fold_uint_expression(*e.right)?.into_inner(),
) {
(UExpressionInner::Value(v1), UExpressionInner::Value(v2)) => {
Ok(UExpression::value(
(v1.value / v2.value) % 2_u128.pow(bitwidth.to_usize().try_into().unwrap()),
))
}
(e, UExpressionInner::Value(v)) => match v.value {
1 => Ok(e),
_ => Ok(UExpression::div(
e.annotate(bitwidth),
UExpressionInner::Value(v).annotate(bitwidth),
)
.into_inner()),
},
(e1, e2) => {
Ok(UExpression::div(e1.annotate(bitwidth), e2.annotate(bitwidth)).into_inner())
}
},
UExpressionInner::Rem(e) => match (
self.fold_uint_expression(*e.left)?.into_inner(),
self.fold_uint_expression(*e.right)?.into_inner(),
) {
(UExpressionInner::Value(v1), UExpressionInner::Value(v2)) => {
Ok(UExpression::value(
(v1.value % v2.value) % 2_u128.pow(bitwidth.to_usize().try_into().unwrap()),
))
}
(e, UExpressionInner::Value(v)) => match v.value {
1 => Ok(UExpression::value(0)),
_ => Ok(UExpression::rem(
e.annotate(bitwidth),
UExpressionInner::Value(v).annotate(bitwidth),
)
.into_inner()),
},
(e1, e2) => {
Ok(UExpression::rem(e1.annotate(bitwidth), e2.annotate(bitwidth)).into_inner())
}
},
UExpressionInner::RightShift(e) => {
let left = self.fold_uint_expression(*e.left)?;
let right = self.fold_uint_expression(*e.right)?;
match (left.into_inner(), right.into_inner()) {
(UExpressionInner::Value(v), UExpressionInner::Value(by)) => {
Ok(UExpression::value(v.value >> by.value))
}
(e, by) => Ok(UExpression::right_shift(
e.annotate(bitwidth),
by.annotate(UBitwidth::B32),
)
.into_inner()),
}
}
UExpressionInner::LeftShift(e) => {
let left = self.fold_uint_expression(*e.left)?;
let right = self.fold_uint_expression(*e.right)?;
match (left.into_inner(), right.into_inner()) {
(UExpressionInner::Value(v), UExpressionInner::Value(by)) => {
Ok(UExpression::value(
(v.value << by.value) & (2_u128.pow(bitwidth as u32) - 1),
))
}
(e, by) => Ok(UExpression::left_shift(
e.annotate(bitwidth),
by.annotate(UBitwidth::B32),
)
.into_inner()),
}
}
UExpressionInner::Xor(e) => match (
self.fold_uint_expression(*e.left)?.into_inner(),
self.fold_uint_expression(*e.right)?.into_inner(),
) {
(UExpressionInner::Value(v1), UExpressionInner::Value(v2)) => {
Ok(UExpression::value(v1.value ^ v2.value))
}
(UExpressionInner::Value(v), e2) | (e2, UExpressionInner::Value(v))
if v.value == 0 =>
{
Ok(e2)
}
(e1, e2) => {
if e1 == e2 {
Ok(UExpression::value(0))
} else {
Ok(
UExpression::xor(e1.annotate(bitwidth), e2.annotate(bitwidth))
.into_inner(),
)
}
}
},
UExpressionInner::And(e) => match (
self.fold_uint_expression(*e.left)?.into_inner(),
self.fold_uint_expression(*e.right)?.into_inner(),
) {
(UExpressionInner::Value(v1), UExpressionInner::Value(v2)) => {
Ok(UExpression::value(v1.value & v2.value))
}
(UExpressionInner::Value(v), _) | (_, UExpressionInner::Value(v))
if v.value == 0 =>
{
Ok(UExpression::value(0))
}
(e1, e2) => {
Ok(UExpression::and(e1.annotate(bitwidth), e2.annotate(bitwidth)).into_inner())
}
},
UExpressionInner::Not(e) => {
let e = self.fold_uint_expression(*e.inner)?.into_inner();
match e {
UExpressionInner::Value(v) => Ok(UExpression::value(
(!v.value) & (2_u128.pow(bitwidth as u32) - 1),
)),
e => Ok(UExpression::not(e.annotate(bitwidth)).into_inner()),
}
}
UExpressionInner::Neg(e) => {
let e = self.fold_uint_expression(*e.inner)?.into_inner();
match e {
UExpressionInner::Value(v) => Ok(UExpression::value(
(0u128.wrapping_sub(v.value))
% 2_u128.pow(bitwidth.to_usize().try_into().unwrap()),
)),
e => Ok(UExpression::neg(e.annotate(bitwidth)).into_inner()),
}
}
UExpressionInner::Pos(e) => {
let e = self.fold_uint_expression(*e.inner)?.into_inner();
match e {
UExpressionInner::Value(v) => Ok(UExpression::value(v.value)),
e => Ok(UExpression::pos(e.annotate(bitwidth)).into_inner()),
}
}
e => fold_uint_expression_cases(self, bitwidth, e),
}
}
fn fold_field_expression_cases(
&mut self,
e: FieldElementExpression<'ast, T>,
) -> Result<FieldElementExpression<'ast, T>, Error> {
match e {
FieldElementExpression::Add(e) => {
let left = self.fold_field_expression(*e.left)?;
let right = self.fold_field_expression(*e.right)?;
Ok(match (left, right) {
(FieldElementExpression::Value(n1), FieldElementExpression::Value(n2)) => {
FieldElementExpression::Value(ValueExpression::new(n1.value + n2.value))
}
(e1, e2) => e1 + e2,
})
}
FieldElementExpression::Sub(e) => {
let left = self.fold_field_expression(*e.left)?;
let right = self.fold_field_expression(*e.right)?;
Ok(match (left, right) {
(FieldElementExpression::Value(n1), FieldElementExpression::Value(n2)) => {
FieldElementExpression::Value(ValueExpression::new(n1.value - n2.value))
}
(e1, e2) => e1 - e2,
})
}
FieldElementExpression::Mult(e) => {
let left = self.fold_field_expression(*e.left)?;
let right = self.fold_field_expression(*e.right)?;
Ok(match (left, right) {
(FieldElementExpression::Value(n1), FieldElementExpression::Value(n2)) => {
FieldElementExpression::Value(ValueExpression::new(n1.value * n2.value))
}
(e1, e2) => e1 * e2,
})
}
FieldElementExpression::Div(e) => {
let left = self.fold_field_expression(*e.left)?;
let right = self.fold_field_expression(*e.right)?;
Ok(match (left, right) {
(FieldElementExpression::Value(n1), FieldElementExpression::Value(n2)) => {
FieldElementExpression::Value(ValueExpression::new(n1.value / n2.value))
}
(e1, e2) => e1 / e2,
})
}
FieldElementExpression::Neg(e) => match self.fold_field_expression(*e.inner)? {
FieldElementExpression::Value(n) => {
Ok(FieldElementExpression::value(T::zero() - n.value))
}
e => Ok(FieldElementExpression::neg(e)),
},
FieldElementExpression::Pos(e) => match self.fold_field_expression(*e.inner)? {
FieldElementExpression::Value(n) => Ok(FieldElementExpression::Value(n)),
e => Ok(FieldElementExpression::pos(e)),
},
FieldElementExpression::Pow(e) => {
let e1 = self.fold_field_expression(*e.left)?;
let e2 = self.fold_uint_expression(*e.right)?;
match (e1, e2.into_inner()) {
(_, UExpressionInner::Value(ref n2)) if n2.value == 0 => {
Ok(FieldElementExpression::value(T::from(1)))
}
(FieldElementExpression::Value(n1), UExpressionInner::Value(n2)) => Ok(
FieldElementExpression::value(n1.value.pow(n2.value as usize)),
),
(e1, e2) => Ok(FieldElementExpression::pow(e1, e2.annotate(UBitwidth::B32))),
}
}
FieldElementExpression::Xor(e) => {
let e1 = self.fold_field_expression(*e.left)?;
let e2 = self.fold_field_expression(*e.right)?;
match (e1, e2) {
(FieldElementExpression::Value(n1), FieldElementExpression::Value(n2)) => {
Ok(FieldElementExpression::value(
T::try_from(n1.value.to_biguint().bitxor(n2.value.to_biguint()))
.unwrap(),
))
}
(FieldElementExpression::Value(n), e)
| (e, FieldElementExpression::Value(n))
if n.value == T::from(0) =>
{
Ok(e)
}
(e1, e2) if e1.eq(&e2) => Ok(FieldElementExpression::value(T::from(0))),
(e1, e2) => Ok(FieldElementExpression::bitxor(e1, e2)),
}
}
FieldElementExpression::And(e) => {
let e1 = self.fold_field_expression(*e.left)?;
let e2 = self.fold_field_expression(*e.right)?;
match (e1, e2) {
(_, FieldElementExpression::Value(n))
| (FieldElementExpression::Value(n), _)
if n.value == T::from(0) =>
{
Ok(FieldElementExpression::Value(n))
}
(FieldElementExpression::Value(n1), FieldElementExpression::Value(n2)) => {
Ok(FieldElementExpression::value(
T::try_from(n1.value.to_biguint().bitand(n2.value.to_biguint()))
.unwrap(),
))
}
(e1, e2) => Ok(FieldElementExpression::bitand(e1, e2)),
}
}
FieldElementExpression::Or(e) => {
let e1 = self.fold_field_expression(*e.left)?;
let e2 = self.fold_field_expression(*e.right)?;
match (e1, e2) {
(e, FieldElementExpression::Value(n))
| (FieldElementExpression::Value(n), e)
if n.value == T::from(0) =>
{
Ok(e)
}
(FieldElementExpression::Value(n1), FieldElementExpression::Value(n2)) => {
Ok(FieldElementExpression::value(
T::try_from(n1.value.to_biguint().bitor(n2.value.to_biguint()))
.unwrap(),
))
}
(e1, e2) => Ok(FieldElementExpression::bitor(e1, e2)),
}
}
FieldElementExpression::LeftShift(e) => {
let expr = self.fold_field_expression(*e.left)?;
let by = self.fold_uint_expression(*e.right)?;
match (expr, by) {
(
e,
UExpression {
inner: UExpressionInner::Value(by),
..
},
) if by.value == 0 => Ok(e),
(
_,
UExpression {
inner: UExpressionInner::Value(by),
..
},
) if by.value as usize >= T::get_required_bits() => {
Ok(FieldElementExpression::value(T::from(0)))
}
(
FieldElementExpression::Value(n),
UExpression {
inner: UExpressionInner::Value(by),
..
},
) => {
let two = BigUint::from(2usize);
let mask: BigUint = two.pow(T::get_required_bits()).sub(1usize);
Ok(FieldElementExpression::value(
T::try_from(n.value.to_biguint().shl(by.value as usize).bitand(mask))
.unwrap(),
))
}
(e, by) => Ok(FieldElementExpression::left_shift(e, by)),
}
}
FieldElementExpression::RightShift(e) => {
let expr = self.fold_field_expression(*e.left)?;
let by = self.fold_uint_expression(*e.right)?;
match (expr, by) {
(
e,
UExpression {
inner: UExpressionInner::Value(by),
..
},
) if by.value == 0 => Ok(e),
(
_,
UExpression {
inner: UExpressionInner::Value(by),
..
},
) if by.value as usize >= T::get_required_bits() => {
Ok(FieldElementExpression::value(T::from(0)))
}
(
FieldElementExpression::Value(n),
UExpression {
inner: UExpressionInner::Value(by),
..
},
) => Ok(FieldElementExpression::value(
T::try_from(n.value.to_biguint().shr(by.value as usize)).unwrap(),
)),
(e, by) => Ok(FieldElementExpression::right_shift(e, by)),
}
}
e => fold_field_expression_cases(self, e),
}
}
fn fold_member_expression<
E: Expr<'ast, T> + Member<'ast, T> + From<TypedExpression<'ast, T>>,
>(
&mut self,
_: &E::Ty,
m: MemberExpression<'ast, T, E>,
) -> Result<MemberOrExpression<'ast, T, E>, Self::Error> {
let id = m.id;
let struc = self.fold_struct_expression(*m.struc)?;
let ty = struc.ty().clone();
match struc.into_inner() {
StructExpressionInner::Value(v) => Ok(MemberOrExpression::Expression(
E::from(
ty.members
.iter()
.zip(v)
.find(|(member, _)| member.id == id)
.unwrap()
.1,
)
.into_inner(),
)),
inner => Ok(MemberOrExpression::Member(MemberExpression::new(
inner.annotate(ty),
id,
))),
}
}
fn fold_element_expression<
E: Expr<'ast, T> + Element<'ast, T> + From<TypedExpression<'ast, T>>,
>(
&mut self,
_: &E::Ty,
m: ElementExpression<'ast, T, E>,
) -> Result<ElementOrExpression<'ast, T, E>, Self::Error> {
let index = m.index;
let tuple = self.fold_tuple_expression(*m.tuple)?;
let ty = tuple.ty().clone();
match tuple.into_inner() {
TupleExpressionInner::Value(v) => Ok(ElementOrExpression::Expression(
E::from(v[index as usize].clone()).into_inner(),
)),
inner => Ok(ElementOrExpression::Element(ElementExpression::new(
inner.annotate(ty),
index,
))),
}
}
fn fold_select_expression<
E: Expr<'ast, T>
+ Select<'ast, T>
+ From<TypedExpression<'ast, T>>
+ Into<TypedExpression<'ast, T>>,
>(
&mut self,
_: &E::Ty,
e: SelectExpression<'ast, T, E>,
) -> Result<SelectOrExpression<'ast, T, E>, Self::Error> {
let index = self.fold_uint_expression(*e.index)?;
let array = *e.array;
let ty = self.fold_array_type(*array.ty)?;
let size = match ty.size.as_inner() {
UExpressionInner::Value(v) => Ok(v),
_ => unreachable!("array size was checked when folding array type"),
}?;
match (array.inner, index.into_inner()) {
// special case if the array is an identifier: check the cache and only clone the element, not the whole array
(ArrayExpressionInner::Identifier(id), UExpressionInner::Value(n)) => {
match self.constants.get(&id.id) {
Some(v) => {
// get the constant array. it was guaranteed to be a value when it was inserted
let v = match v {
TypedExpression::Array(a) => match a.as_inner() {
ArrayExpressionInner::Value(v) => v,
_ => unreachable!(),
},
_ => unreachable!(),
};
// sanity check that the value does not contain spreads
assert!(v
.value
.iter()
.all(|e| matches!(e, TypedExpressionOrSpread::Expression(_))));
if n.value < size.value {
Ok(SelectOrExpression::Expression(
// clone only the element
match v.value[n.value as usize].clone() {
TypedExpressionOrSpread::Expression(e) => {
E::try_from(e).unwrap().into_inner()
}
_ => unreachable!(),
},
))
} else {
Err(Error::OutOfBounds(n.value, size.value))
}
}
_ => Ok(SelectOrExpression::Select(SelectExpression::new(
ArrayExpressionInner::Identifier(id).annotate(ty),
UExpressionInner::Value(n).annotate(UBitwidth::B32),
))),
}
}
(array, index) => {
let array = self.fold_array_expression_inner(&ty, array)?;
match (array, index) {
(ArrayExpressionInner::Value(v), UExpressionInner::Value(n)) => {
if n.value < size.value {
Ok(SelectOrExpression::Expression(
v.expression_at::<E>(n.value as usize).into_inner(),
))
} else {
Err(Error::OutOfBounds(n.value, size.value))
}
}
(a, i) => Ok(SelectOrExpression::Select(SelectExpression::new(
a.annotate(ty),
i.annotate(UBitwidth::B32),
))),
}
}
}
}
fn fold_array_type(
&mut self,
t: ArrayType<'ast, T>,
) -> Result<ArrayType<'ast, T>, Self::Error> {
let size = self.fold_uint_expression(*t.size)?;
if !size.is_constant() {
return Err(Error::VariableLength(format!(
"Array length should be fixed, found {}",
size
)));
}
Ok(ArrayType::new(self.fold_type(*t.ty)?, size))
}
fn fold_array_expression_cases(
&mut self,
ty: &ArrayType<'ast, T>,
e: ArrayExpressionInner<'ast, T>,
) -> Result<ArrayExpressionInner<'ast, T>, Error> {
match e {
ArrayExpressionInner::Value(exprs) => {
Ok(ArrayExpressionInner::Value(
exprs
.into_iter()
.map(|e| self.fold_expression_or_spread(e))
.collect::<Result<Vec<_>, _>>()?
.into_iter()
.flat_map(|e| {
match e {
// simplify `...[a, b]` to `a, b`
TypedExpressionOrSpread::Spread(TypedSpread {
array:
ArrayExpression {
inner: ArrayExpressionInner::Value(v),
..
},
}) => v.value,
e => vec![e],
}
})
// ignore spreads over empty arrays
.filter_map(|e| match e {
// clippy makes a wrong suggestion here:
// ```
// this creates an owned instance just for comparison
// UExpression::from(0u32)
// help: try: `0u32`
// ```
// But for `UExpression`, `PartialEq<Self>` is different from `PartialEq<u32>` (the latter is too optimistic in this case)
#[allow(clippy::cmp_owned)]
TypedExpressionOrSpread::Spread(s)
if s.array.size() == UExpression::from(0u32) =>
{
None
}
e => Some(e),
})
.collect(),
))
}
e => fold_array_expression_cases(self, ty, e),
}
}
fn fold_struct_expression_cases(
&mut self,
ty: &StructType<'ast, T>,
e: StructExpressionInner<'ast, T>,
) -> Result<StructExpressionInner<'ast, T>, Error> {
match e {
StructExpressionInner::Value(v) => {
let v = v.into_iter().zip(ty.iter()).map(|(v, member)|
match self.fold_expression(v) {
Ok(v) => match (ConcreteType::try_from(v.get_type().clone()), ConcreteType::try_from(*member.ty.clone())) {
(Ok(t1), Ok(t2)) => if t1 == t2 { Ok(v) } else { Err(Error::Type(format!(
"Struct member `{}` in struct `{}/{}` expected to have type `{}`, found type `{}`",
member.id, ty.canonical_location.clone().module.display(), ty.canonical_location.clone().name, t2, t1
))) },
_ => Ok(v)
}
e => e
}
).collect::<Result<_, _>>()?;
Ok(StructExpressionInner::Value(v))
}
e => fold_struct_expression_cases(self, ty, e),
}
}
fn fold_identifier_expression<
E: Expr<'ast, T> + Id<'ast, T> + ResultFold<Self, Self::Error>,
>(
&mut self,
_: &E::Ty,
id: IdentifierExpression<'ast, E>,
) -> Result<IdentifierOrExpression<'ast, T, E>, Self::Error> {
match self.constants.get(&id.id).cloned() {
Some(e) => Ok(IdentifierOrExpression::Expression(E::from(e).into_inner())),
None => Ok(IdentifierOrExpression::Identifier(id)),
}
}
fn fold_tuple_expression_cases(
&mut self,
ty: &TupleType<'ast, T>,
e: TupleExpressionInner<'ast, T>,
) -> Result<TupleExpressionInner<'ast, T>, Error> {
match e {
TupleExpressionInner::Value(v) => {
let v = v.into_iter().zip(ty.elements.iter().enumerate()).map(|(v, (index, element_ty))|
match self.fold_expression(v) {
Ok(v) => match (ConcreteType::try_from(v.get_type().clone()), ConcreteType::try_from(element_ty.clone())) {
(Ok(t1), Ok(t2)) => if t1 == t2 { Ok(v) } else { Err(Error::Type(format!(
"Tuple element `{}` in tuple `{}` expected to have type `{}`, found type `{}`",
index, ty, t2, t1
))) },
_ => Ok(v)
}
e => e
}
).collect::<Result<_, _>>()?;
Ok(TupleExpressionInner::Value(v))
}
e => fold_tuple_expression_cases(self, ty, e),
}
}
fn fold_eq_expression<
E: Expr<'ast, T> + PartialEq + Constant + Typed<'ast, T> + ResultFold<Self, Self::Error>,
>(
&mut self,
e: EqExpression<E, BooleanExpression<'ast, T>>,
) -> Result<
BinaryOrExpression<OpEq, E, E, BooleanExpression<'ast, T>, BooleanExpression<'ast, T>>,
Self::Error,
> {
let left = e.left.fold(self)?;
let right = e.right.fold(self)?;
if let (Ok(t_left), Ok(t_right)) = (
ConcreteType::try_from(left.get_type()),
ConcreteType::try_from(right.get_type()),
) {
if t_left != t_right {
return Err(Error::Type(format!(
"Cannot compare {} of type {} to {} of type {}",
left, t_left, right, t_right
)));
}
};
// if the two expressions are the same, we can reduce to `true`.
// Note that if they are different we cannot reduce to `false`: `a == 1` may still be `true` even though `a` and `1` are different expressions
if left == right {
return Ok(BinaryOrExpression::Expression(BooleanExpression::value(
true,
)));
}
// if both expressions are constant, we can reduce the equality check after we put them in canonical form
if left.is_constant() && right.is_constant() {
let left = left.into_canonical_constant();
let right = right.into_canonical_constant();
Ok(BinaryOrExpression::Expression(BooleanExpression::value(
left == right,
)))
} else {
Ok(BinaryOrExpression::Binary(BinaryExpression::new(
left, right,
)))
}
}
fn fold_boolean_expression_cases(
&mut self,
e: BooleanExpression<'ast, T>,
) -> Result<BooleanExpression<'ast, T>, Error> {
// Note: we only propagate when we see constants, as comparing of arbitrary expressions would lead to
// a lot of false negatives due to expressions not being in a canonical form
// For example, `2 * a` is equivalent to `a + a`, but our notion of equality would not detect that here
// These kind of reduction rules are easier to apply later in the process, when we have canonical representations
// of expressions, ie `a + a` would always be written `2 * a`
match e {
BooleanExpression::FieldLt(e) => {
let e1 = self.fold_field_expression(*e.left)?;
let e2 = self.fold_field_expression(*e.right)?;
match (e1, e2) {
(FieldElementExpression::Value(n1), FieldElementExpression::Value(n2)) => {
Ok(BooleanExpression::value(n1.value < n2.value))
}
(e1, e2) => Ok(BooleanExpression::field_lt(e1, e2)),
}
}
BooleanExpression::FieldLe(e) => {
let e1 = self.fold_field_expression(*e.left)?;
let e2 = self.fold_field_expression(*e.right)?;
match (e1, e2) {
(FieldElementExpression::Value(n1), FieldElementExpression::Value(n2)) => {
Ok(BooleanExpression::value(n1.value <= n2.value))
}
(e1, e2) => Ok(BooleanExpression::field_le(e1, e2)),
}
}
BooleanExpression::UintLt(e) => {
let e1 = self.fold_uint_expression(*e.left)?;
let e2 = self.fold_uint_expression(*e.right)?;
match (e1.as_inner(), e2.as_inner()) {
(UExpressionInner::Value(n1), UExpressionInner::Value(n2)) => {
Ok(BooleanExpression::value(n1.value < n2.value))
}
_ => Ok(BooleanExpression::uint_lt(e1, e2)),
}
}
BooleanExpression::UintLe(e) => {
let e1 = self.fold_uint_expression(*e.left)?;
let e2 = self.fold_uint_expression(*e.right)?;
match (e1.as_inner(), e2.as_inner()) {
(UExpressionInner::Value(n1), UExpressionInner::Value(n2)) => {
Ok(BooleanExpression::value(n1.value <= n2.value))
}
_ => Ok(BooleanExpression::uint_le(e1, e2)),
}
}
BooleanExpression::Or(e) => {
let e1 = self.fold_boolean_expression(*e.left)?;
let e2 = self.fold_boolean_expression(*e.right)?;
match (e1, e2) {
// reduction of constants
(BooleanExpression::Value(v1), BooleanExpression::Value(v2)) => {
Ok(BooleanExpression::value(v1.value || v2.value))
}
// x || true == true
(_, BooleanExpression::Value(v)) | (BooleanExpression::Value(v), _)
if v.value =>
{
Ok(BooleanExpression::value(true))
}
// x || false == x
(e, BooleanExpression::Value(v)) | (BooleanExpression::Value(v), e)
if !v.value =>
{
Ok(e)
}
(e1, e2) => Ok(BooleanExpression::bitor(e1, e2)),
}
}
BooleanExpression::And(e) => {
let e1 = self.fold_boolean_expression(*e.left)?;
let e2 = self.fold_boolean_expression(*e.right)?;
match (e1, e2) {
// reduction of constants
(BooleanExpression::Value(v1), BooleanExpression::Value(v2)) => {
Ok(BooleanExpression::value(v1.value && v2.value))
}
// x && true == x
(e, BooleanExpression::Value(v)) | (BooleanExpression::Value(v), e)
if v.value =>
{
Ok(e)
}
// x && false == false
(_, BooleanExpression::Value(v)) | (BooleanExpression::Value(v), _)
if !v.value =>
{
Ok(BooleanExpression::value(false))
}
(e1, e2) => Ok(BooleanExpression::bitand(e1, e2)),
}
}
BooleanExpression::Not(e) => {
let e = self.fold_boolean_expression(*e.inner)?;
match e {
BooleanExpression::Value(v) => Ok(BooleanExpression::value(!v.value)),
e => Ok(BooleanExpression::not(e)),
}
}
e => fold_boolean_expression_cases(self, e),
}
}
}
#[cfg(test)]
mod tests {
use super::*;
use zokrates_field::Bn128Field;
#[cfg(test)]
mod expression {
use super::*;
#[cfg(test)]
mod field {
use super::*;
#[test]
fn add() {
let e = FieldElementExpression::add(
FieldElementExpression::value(Bn128Field::from(2)),
FieldElementExpression::value(Bn128Field::from(3)),
);
assert_eq!(
Propagator::default().fold_field_expression(e),
Ok(FieldElementExpression::value(Bn128Field::from(5)))
);
}
#[test]
fn sub() {
let e = FieldElementExpression::sub(
FieldElementExpression::value(Bn128Field::from(3)),
FieldElementExpression::value(Bn128Field::from(2)),
);
assert_eq!(
Propagator::default().fold_field_expression(e),
Ok(FieldElementExpression::value(Bn128Field::from(1)))
);
}
#[test]
fn mult() {
let e = FieldElementExpression::mul(
FieldElementExpression::value(Bn128Field::from(3)),
FieldElementExpression::value(Bn128Field::from(2)),
);
assert_eq!(
Propagator::default().fold_field_expression(e),
Ok(FieldElementExpression::value(Bn128Field::from(6)))
);
}
#[test]
fn div() {
let e = FieldElementExpression::div(
FieldElementExpression::value(Bn128Field::from(6)),
FieldElementExpression::value(Bn128Field::from(2)),
);
assert_eq!(
Propagator::default().fold_field_expression(e),
Ok(FieldElementExpression::value(Bn128Field::from(3)))
);
}
#[test]
fn pow() {
let e = FieldElementExpression::pow(
FieldElementExpression::value(Bn128Field::from(2)),
3u32.into(),
);
assert_eq!(
Propagator::default().fold_field_expression(e),
Ok(FieldElementExpression::value(Bn128Field::from(8)))
);
}
#[test]
fn left_shift() {
let mut propagator = Propagator::default();
assert_eq!(
propagator.fold_field_expression(FieldElementExpression::left_shift(
FieldElementExpression::identifier("a".into()),
0u32.into(),
)),
Ok(FieldElementExpression::identifier("a".into()))
);
assert_eq!(
propagator.fold_field_expression(FieldElementExpression::left_shift(
FieldElementExpression::value(Bn128Field::from(2)),
2u32.into(),
)),
Ok(FieldElementExpression::value(Bn128Field::from(8)))
);
assert_eq!(
propagator.fold_field_expression(FieldElementExpression::left_shift(
FieldElementExpression::value(Bn128Field::from(1)),
((Bn128Field::get_required_bits() - 1) as u32).into(),
)),
Ok(FieldElementExpression::value(Bn128Field::try_from_dec_str("14474011154664524427946373126085988481658748083205070504932198000989141204992").unwrap()))
);
assert_eq!(
propagator.fold_field_expression(FieldElementExpression::left_shift(
FieldElementExpression::value(Bn128Field::from(3)),
((Bn128Field::get_required_bits() - 3) as u32).into(),
)),
Ok(FieldElementExpression::value(Bn128Field::try_from_dec_str("10855508365998393320959779844564491361244061062403802878699148500741855903744").unwrap()))
);
assert_eq!(
propagator.fold_field_expression(FieldElementExpression::left_shift(
FieldElementExpression::value(Bn128Field::from(1)),
(Bn128Field::get_required_bits() as u32).into(),
)),
Ok(FieldElementExpression::value(Bn128Field::from(0)))
);
}
#[test]
fn right_shift() {
let mut propagator = Propagator::default();
assert_eq!(
propagator.fold_field_expression(FieldElementExpression::right_shift(
FieldElementExpression::identifier("a".into()),
0u32.into(),
)),
Ok(FieldElementExpression::identifier("a".into()))
);
assert_eq!(
propagator.fold_field_expression(FieldElementExpression::right_shift(
FieldElementExpression::identifier("a".into()),
(Bn128Field::get_required_bits() as u32).into(),
)),
Ok(FieldElementExpression::value(Bn128Field::from(0)))
);
assert_eq!(
propagator.fold_field_expression(FieldElementExpression::right_shift(
FieldElementExpression::value(Bn128Field::from(3)),
1u32.into(),
)),
Ok(FieldElementExpression::value(Bn128Field::from(1)))
);
assert_eq!(
propagator.fold_field_expression(FieldElementExpression::right_shift(
FieldElementExpression::value(Bn128Field::from(2)),
2u32.into(),
)),
Ok(FieldElementExpression::value(Bn128Field::from(0)))
);
assert_eq!(
propagator.fold_field_expression(FieldElementExpression::right_shift(
FieldElementExpression::value(Bn128Field::from(2)),
4u32.into(),
)),
Ok(FieldElementExpression::value(Bn128Field::from(0)))
);
assert_eq!(
propagator.fold_field_expression(FieldElementExpression::right_shift(
FieldElementExpression::value(Bn128Field::max_value()),
((Bn128Field::get_required_bits() - 1) as u32).into(),
)),
Ok(FieldElementExpression::value(Bn128Field::from(1)))
);
assert_eq!(
propagator.fold_field_expression(FieldElementExpression::right_shift(
FieldElementExpression::value(Bn128Field::max_value()),
(Bn128Field::get_required_bits() as u32).into(),
)),
Ok(FieldElementExpression::value(Bn128Field::from(0)))
);
}
#[test]
fn if_else_true() {
let e = FieldElementExpression::conditional(
BooleanExpression::value(true),
FieldElementExpression::value(Bn128Field::from(2)),
FieldElementExpression::value(Bn128Field::from(3)),
ConditionalKind::IfElse,
);
assert_eq!(
Propagator::default().fold_field_expression(e),
Ok(FieldElementExpression::value(Bn128Field::from(2)))
);
}
#[test]
fn if_else_false() {
let e = FieldElementExpression::conditional(
BooleanExpression::value(false),
FieldElementExpression::value(Bn128Field::from(2)),
FieldElementExpression::value(Bn128Field::from(3)),
ConditionalKind::IfElse,
);
assert_eq!(
Propagator::default().fold_field_expression(e),
Ok(FieldElementExpression::value(Bn128Field::from(3)))
);
}
#[test]
fn select() {
let e = FieldElementExpression::select(
ArrayExpression::value(vec![
FieldElementExpression::value(Bn128Field::from(1)).into(),
FieldElementExpression::value(Bn128Field::from(2)).into(),
FieldElementExpression::value(Bn128Field::from(3)).into(),
])
.annotate(ArrayType::new(Type::FieldElement, 3u32)),
UExpression::add(1u32.into(), 1u32.into()),
);
assert_eq!(
Propagator::default().fold_field_expression(e),
Ok(FieldElementExpression::value(Bn128Field::from(3)))
);
}
}
#[cfg(test)]
mod boolean {
use super::*;
#[test]
fn not() {
let e_true: BooleanExpression<Bn128Field> =
BooleanExpression::not(BooleanExpression::value(false));
let e_false: BooleanExpression<Bn128Field> =
BooleanExpression::not(BooleanExpression::value(true));
let e_default: BooleanExpression<Bn128Field> =
BooleanExpression::not(BooleanExpression::identifier("a".into()));
assert_eq!(
Propagator::default().fold_boolean_expression(e_true),
Ok(BooleanExpression::value(true))
);
assert_eq!(
Propagator::default().fold_boolean_expression(e_false),
Ok(BooleanExpression::value(false))
);
assert_eq!(
Propagator::default().fold_boolean_expression(e_default.clone()),
Ok(e_default)
);
}
#[test]
fn field_eq() {
let e_constant_true = BooleanExpression::FieldEq(BinaryExpression::new(
FieldElementExpression::value(Bn128Field::from(2)),
FieldElementExpression::value(Bn128Field::from(2)),
));
let e_constant_false = BooleanExpression::FieldEq(BinaryExpression::new(
FieldElementExpression::value(Bn128Field::from(4)),
FieldElementExpression::value(Bn128Field::from(2)),
));
let e_identifier_true: BooleanExpression<Bn128Field> =
BooleanExpression::FieldEq(BinaryExpression::new(
FieldElementExpression::identifier("a".into()),
FieldElementExpression::identifier("a".into()),
));
let e_identifier_unchanged: BooleanExpression<Bn128Field> =
BooleanExpression::FieldEq(BinaryExpression::new(
FieldElementExpression::identifier("a".into()),
FieldElementExpression::identifier("b".into()),
));
assert_eq!(
Propagator::default().fold_boolean_expression(e_constant_true),
Ok(BooleanExpression::value(true))
);
assert_eq!(
Propagator::default().fold_boolean_expression(e_constant_false),
Ok(BooleanExpression::value(false))
);
assert_eq!(
Propagator::default().fold_boolean_expression(e_identifier_true),
Ok(BooleanExpression::value(true))
);
assert_eq!(
Propagator::default().fold_boolean_expression(e_identifier_unchanged.clone()),
Ok(e_identifier_unchanged)
);
}
#[test]
fn bool_eq() {
assert_eq!(
Propagator::<Bn128Field>::default().fold_boolean_expression(
BooleanExpression::BoolEq(EqExpression::new(
BooleanExpression::value(false),
BooleanExpression::value(false)
))
),
Ok(BooleanExpression::value(true))
);
assert_eq!(
Propagator::<Bn128Field>::default().fold_boolean_expression(
BooleanExpression::BoolEq(EqExpression::new(
BooleanExpression::value(true),
BooleanExpression::value(true)
))
),
Ok(BooleanExpression::value(true))
);
assert_eq!(
Propagator::<Bn128Field>::default().fold_boolean_expression(
BooleanExpression::BoolEq(EqExpression::new(
BooleanExpression::value(true),
BooleanExpression::value(false)
))
),
Ok(BooleanExpression::value(false))
);
assert_eq!(
Propagator::<Bn128Field>::default().fold_boolean_expression(
BooleanExpression::BoolEq(EqExpression::new(
BooleanExpression::value(false),
BooleanExpression::value(true)
))
),
Ok(BooleanExpression::value(false))
);
}
#[test]
fn array_eq() {
let e_constant_true = BooleanExpression::ArrayEq(BinaryExpression::new(
ArrayExpression::value(vec![TypedExpressionOrSpread::Expression(
FieldElementExpression::value(Bn128Field::from(2usize)).into(),
)])
.annotate(ArrayType::new(Type::FieldElement, 1u32)),
ArrayExpression::value(vec![TypedExpressionOrSpread::Expression(
FieldElementExpression::value(Bn128Field::from(2usize)).into(),
)])
.annotate(ArrayType::new(Type::FieldElement, 1u32)),
));
let e_constant_false = BooleanExpression::ArrayEq(BinaryExpression::new(
ArrayExpression::value(vec![TypedExpressionOrSpread::Expression(
FieldElementExpression::value(Bn128Field::from(2usize)).into(),
)])
.annotate(ArrayType::new(Type::FieldElement, 1u32)),
ArrayExpression::value(vec![TypedExpressionOrSpread::Expression(
FieldElementExpression::value(Bn128Field::from(4usize)).into(),
)])
.annotate(ArrayType::new(Type::FieldElement, 1u32)),
));
let e_identifier_true: BooleanExpression<Bn128Field> =
BooleanExpression::ArrayEq(BinaryExpression::new(
ArrayExpression::identifier("a".into())
.annotate(ArrayType::new(Type::FieldElement, 1u32)),
ArrayExpression::identifier("a".into())
.annotate(ArrayType::new(Type::FieldElement, 1u32)),
));
let e_identifier_unchanged: BooleanExpression<Bn128Field> =
BooleanExpression::ArrayEq(BinaryExpression::new(
ArrayExpression::identifier("a".into())
.annotate(ArrayType::new(Type::FieldElement, 1u32)),
ArrayExpression::identifier("b".into())
.annotate(ArrayType::new(Type::FieldElement, 1u32)),
));
let e_non_canonical_true = BooleanExpression::ArrayEq(BinaryExpression::new(
ArrayExpression::value(vec![TypedExpressionOrSpread::Spread(
ArrayExpression::value(vec![TypedExpressionOrSpread::Expression(
FieldElementExpression::value(Bn128Field::from(2usize)).into(),
)])
.annotate(ArrayType::new(Type::FieldElement, 1u32))
.into(),
)])
.annotate(ArrayType::new(Type::FieldElement, 1u32)),
ArrayExpression::value(vec![TypedExpressionOrSpread::Expression(
FieldElementExpression::value(Bn128Field::from(2usize)).into(),
)])
.annotate(ArrayType::new(Type::FieldElement, 1u32)),
));
let e_non_canonical_false = BooleanExpression::ArrayEq(BinaryExpression::new(
ArrayExpression::value(vec![TypedExpressionOrSpread::Spread(
ArrayExpression::value(vec![TypedExpressionOrSpread::Expression(
FieldElementExpression::value(Bn128Field::from(2usize)).into(),
)])
.annotate(ArrayType::new(Type::FieldElement, 1u32))
.into(),
)])
.annotate(ArrayType::new(Type::FieldElement, 1u32)),
ArrayExpression::value(vec![TypedExpressionOrSpread::Expression(
FieldElementExpression::value(Bn128Field::from(4usize)).into(),
)])
.annotate(ArrayType::new(Type::FieldElement, 1u32)),
));
assert_eq!(
Propagator::default().fold_boolean_expression(e_constant_true),
Ok(BooleanExpression::value(true))
);
assert_eq!(
Propagator::default().fold_boolean_expression(e_constant_false),
Ok(BooleanExpression::value(false))
);
assert_eq!(
Propagator::default().fold_boolean_expression(e_identifier_true),
Ok(BooleanExpression::value(true))
);
assert_eq!(
Propagator::default().fold_boolean_expression(e_identifier_unchanged.clone()),
Ok(e_identifier_unchanged)
);
assert_eq!(
Propagator::default().fold_boolean_expression(e_non_canonical_true),
Ok(BooleanExpression::value(true))
);
assert_eq!(
Propagator::default().fold_boolean_expression(e_non_canonical_false),
Ok(BooleanExpression::value(false))
);
}
#[test]
fn lt() {
let e_true = BooleanExpression::field_lt(
FieldElementExpression::value(Bn128Field::from(2)),
FieldElementExpression::value(Bn128Field::from(4)),
);
let e_false = BooleanExpression::field_lt(
FieldElementExpression::value(Bn128Field::from(4)),
FieldElementExpression::value(Bn128Field::from(2)),
);
assert_eq!(
Propagator::default().fold_boolean_expression(e_true),
Ok(BooleanExpression::value(true))
);
assert_eq!(
Propagator::default().fold_boolean_expression(e_false),
Ok(BooleanExpression::value(false))
);
}
#[test]
fn le() {
let e_true = BooleanExpression::field_le(
FieldElementExpression::value(Bn128Field::from(2)),
FieldElementExpression::value(Bn128Field::from(2)),
);
let e_false = BooleanExpression::field_le(
FieldElementExpression::value(Bn128Field::from(4)),
FieldElementExpression::value(Bn128Field::from(2)),
);
assert_eq!(
Propagator::default().fold_boolean_expression(e_true),
Ok(BooleanExpression::value(true))
);
assert_eq!(
Propagator::default().fold_boolean_expression(e_false),
Ok(BooleanExpression::value(false))
);
}
#[test]
fn gt() {
let e_true = BooleanExpression::field_gt(
FieldElementExpression::value(Bn128Field::from(5)),
FieldElementExpression::value(Bn128Field::from(4)),
);
let e_false = BooleanExpression::field_gt(
FieldElementExpression::value(Bn128Field::from(4)),
FieldElementExpression::value(Bn128Field::from(5)),
);
assert_eq!(
Propagator::default().fold_boolean_expression(e_true),
Ok(BooleanExpression::value(true))
);
assert_eq!(
Propagator::default().fold_boolean_expression(e_false),
Ok(BooleanExpression::value(false))
);
}
#[test]
fn ge() {
let e_true = BooleanExpression::field_ge(
FieldElementExpression::value(Bn128Field::from(5)),
FieldElementExpression::value(Bn128Field::from(5)),
);
let e_false = BooleanExpression::field_ge(
FieldElementExpression::value(Bn128Field::from(4)),
FieldElementExpression::value(Bn128Field::from(5)),
);
assert_eq!(
Propagator::default().fold_boolean_expression(e_true),
Ok(BooleanExpression::value(true))
);
assert_eq!(
Propagator::default().fold_boolean_expression(e_false),
Ok(BooleanExpression::value(false))
);
}
#[test]
fn and() {
let a_bool: Identifier = "a".into();
assert_eq!(
Propagator::<Bn128Field>::default().fold_boolean_expression(
BooleanExpression::bitand(
BooleanExpression::value(true),
BooleanExpression::identifier(a_bool.clone())
)
),
Ok(BooleanExpression::identifier(a_bool.clone()))
);
assert_eq!(
Propagator::<Bn128Field>::default().fold_boolean_expression(
BooleanExpression::bitand(
BooleanExpression::identifier(a_bool.clone()),
BooleanExpression::value(true),
)
),
Ok(BooleanExpression::identifier(a_bool.clone()))
);
assert_eq!(
Propagator::<Bn128Field>::default().fold_boolean_expression(
BooleanExpression::bitand(
BooleanExpression::value(false),
BooleanExpression::identifier(a_bool.clone())
)
),
Ok(BooleanExpression::value(false))
);
assert_eq!(
Propagator::<Bn128Field>::default().fold_boolean_expression(
BooleanExpression::bitand(
BooleanExpression::identifier(a_bool.clone()),
BooleanExpression::value(false),
)
),
Ok(BooleanExpression::value(false))
);
assert_eq!(
Propagator::<Bn128Field>::default().fold_boolean_expression(
BooleanExpression::bitand(
BooleanExpression::value(true),
BooleanExpression::value(false),
)
),
Ok(BooleanExpression::value(false))
);
assert_eq!(
Propagator::<Bn128Field>::default().fold_boolean_expression(
BooleanExpression::bitand(
BooleanExpression::value(false),
BooleanExpression::value(true),
)
),
Ok(BooleanExpression::value(false))
);
assert_eq!(
Propagator::<Bn128Field>::default().fold_boolean_expression(
BooleanExpression::bitand(
BooleanExpression::value(true),
BooleanExpression::value(true),
)
),
Ok(BooleanExpression::value(true))
);
assert_eq!(
Propagator::<Bn128Field>::default().fold_boolean_expression(
BooleanExpression::bitand(
BooleanExpression::value(false),
BooleanExpression::value(false),
)
),
Ok(BooleanExpression::value(false))
);
}
#[test]
fn or() {
let a_bool: Identifier = "a".into();
assert_eq!(
Propagator::<Bn128Field>::default().fold_boolean_expression(
BooleanExpression::bitor(
BooleanExpression::value(true),
BooleanExpression::identifier(a_bool.clone())
)
),
Ok(BooleanExpression::value(true))
);
assert_eq!(
Propagator::<Bn128Field>::default().fold_boolean_expression(
BooleanExpression::bitor(
BooleanExpression::identifier(a_bool.clone()),
BooleanExpression::value(true),
)
),
Ok(BooleanExpression::value(true))
);
assert_eq!(
Propagator::<Bn128Field>::default().fold_boolean_expression(
BooleanExpression::bitor(
BooleanExpression::value(false),
BooleanExpression::identifier(a_bool.clone())
)
),
Ok(BooleanExpression::identifier(a_bool.clone()))
);
assert_eq!(
Propagator::<Bn128Field>::default().fold_boolean_expression(
BooleanExpression::bitor(
BooleanExpression::identifier(a_bool.clone()),
BooleanExpression::value(false),
)
),
Ok(BooleanExpression::identifier(a_bool.clone()))
);
assert_eq!(
Propagator::<Bn128Field>::default().fold_boolean_expression(
BooleanExpression::bitor(
BooleanExpression::value(true),
BooleanExpression::value(false),
)
),
Ok(BooleanExpression::value(true))
);
assert_eq!(
Propagator::<Bn128Field>::default().fold_boolean_expression(
BooleanExpression::bitor(
BooleanExpression::value(false),
BooleanExpression::value(true),
)
),
Ok(BooleanExpression::value(true))
);
assert_eq!(
Propagator::<Bn128Field>::default().fold_boolean_expression(
BooleanExpression::bitor(
BooleanExpression::value(true),
BooleanExpression::value(true),
)
),
Ok(BooleanExpression::value(true))
);
assert_eq!(
Propagator::<Bn128Field>::default().fold_boolean_expression(
BooleanExpression::bitor(
BooleanExpression::value(false),
BooleanExpression::value(false),
)
),
Ok(BooleanExpression::value(false))
);
}
}
}
}