feat(acvm)!: update black box solver interfaces to match `pwg:black_b…

…ox::solve` (#268)

* feat!: update black box solver interfaces to match `pwg:black_box::solve`

* fix: fix build errors

* chore: remove outputs from `StubbedPwg::range`

* chore: remove unnecessary scopes

acvm/src/compiler/transformers/fallback.rs

@@ -76,7 +76,8 @@ impl FallbackTransformer {
     ) -> Result<(u32, Vec<Opcode>), CompileError> {
         let (updated_witness_index, opcodes_fallback) = match gc.name {
             BlackBoxFunc::AND => {
-                let (lhs, rhs, result, num_bits) = crate::pwg::logic::extract_input_output(gc);
+                let (lhs, rhs, result, num_bits) =
+                    crate::pwg::logic::extract_input_output(&gc.inputs, &gc.outputs);
                 stdlib::fallback::and(
                     Expression::from(lhs),
                     Expression::from(rhs),
@@ -86,7 +87,8 @@ impl FallbackTransformer {
                 )
             }
             BlackBoxFunc::XOR => {
-                let (lhs, rhs, result, num_bits) = crate::pwg::logic::extract_input_output(gc);
+                let (lhs, rhs, result, num_bits) =
+                    crate::pwg::logic::extract_input_output(&gc.inputs, &gc.outputs);
                 stdlib::fallback::xor(
                     Expression::from(lhs),
                     Expression::from(rhs),

acvm/src/lib.rs

@@ -82,7 +82,6 @@ pub trait PartialWitnessGenerator {
         &self,
         initial_witness: &mut BTreeMap<Witness, FieldElement>,
         inputs: &[FunctionInput],
-        outputs: &[Witness],
     ) -> Result<pwg::OpcodeResolution, OpcodeResolutionError>;
     fn sha256(
         &self,
@@ -283,129 +282,102 @@ mod test {
             _inputs: &[FunctionInput],
             _outputs: &[Witness],
         ) -> Result<OpcodeResolution, OpcodeResolutionError> {
-            {
-                panic!("Path not trodden by this test")
-            }
+            panic!("Path not trodden by this test")
         }
         fn and(
             &self,
             _initial_witness: &mut BTreeMap<Witness, FieldElement>,
             _inputs: &[FunctionInput],
             _outputs: &[Witness],
         ) -> Result<OpcodeResolution, OpcodeResolutionError> {
-            {
-                panic!("Path not trodden by this test")
-            }
+            panic!("Path not trodden by this test")
         }
         fn xor(
             &self,
             _initial_witness: &mut BTreeMap<Witness, FieldElement>,
             _inputs: &[FunctionInput],
             _outputs: &[Witness],
         ) -> Result<OpcodeResolution, OpcodeResolutionError> {
-            {
-                panic!("Path not trodden by this test")
-            }
+            panic!("Path not trodden by this test")
         }
         fn range(
             &self,
             _initial_witness: &mut BTreeMap<Witness, FieldElement>,
             _inputs: &[FunctionInput],
-            _outputs: &[Witness],
         ) -> Result<OpcodeResolution, OpcodeResolutionError> {
-            {
-                panic!("Path not trodden by this test")
-            }
+            panic!("Path not trodden by this test")
         }
         fn sha256(
             &self,
             _initial_witness: &mut BTreeMap<Witness, FieldElement>,
             _inputs: &[FunctionInput],
             _outputs: &[Witness],
         ) -> Result<OpcodeResolution, OpcodeResolutionError> {
-            {
-                panic!("Path not trodden by this test")
-            }
+            panic!("Path not trodden by this test")
         }
         fn blake2s(
             &self,
             _initial_witness: &mut BTreeMap<Witness, FieldElement>,
             _inputs: &[FunctionInput],
             _outputs: &[Witness],
         ) -> Result<OpcodeResolution, OpcodeResolutionError> {
-            {
-                panic!("Path not trodden by this test")
-            }
+            panic!("Path not trodden by this test")
         }
         fn compute_merkle_root(
             &self,
             _initial_witness: &mut BTreeMap<Witness, FieldElement>,
             _inputs: &[FunctionInput],
             _outputs: &[Witness],
         ) -> Result<OpcodeResolution, OpcodeResolutionError> {
-            {
-                panic!("Path not trodden by this test")
-            }
+            panic!("Path not trodden by this test")
         }
         fn schnorr_verify(
             &self,
             _initial_witness: &mut BTreeMap<Witness, FieldElement>,
             _inputs: &[FunctionInput],
             _outputs: &[Witness],
         ) -> Result<OpcodeResolution, OpcodeResolutionError> {
-            {
-                panic!("Path not trodden by this test")
-            }
+            panic!("Path not trodden by this test")
         }
         fn pedersen(
             &self,
             _initial_witness: &mut BTreeMap<Witness, FieldElement>,
             _inputs: &[FunctionInput],
             _outputs: &[Witness],
         ) -> Result<OpcodeResolution, OpcodeResolutionError> {
-            {
-                panic!("Path not trodden by this test")
-            }
+            panic!("Path not trodden by this test")
         }
         fn hash_to_field128_security(
             &self,
             _initial_witness: &mut BTreeMap<Witness, FieldElement>,
             _inputs: &[FunctionInput],
             _outputs: &[Witness],
         ) -> Result<OpcodeResolution, OpcodeResolutionError> {
-            {
-                panic!("Path not trodden by this test")
-            }
+            panic!("Path not trodden by this test")
         }
         fn ecdsa_secp256k1(
             &self,
             _initial_witness: &mut BTreeMap<Witness, FieldElement>,
             _inputs: &[FunctionInput],
             _outputs: &[Witness],
         ) -> Result<OpcodeResolution, OpcodeResolutionError> {
-            {
-                panic!("Path not trodden by this test")
-            }
+            panic!("Path not trodden by this test")
         }
         fn fixed_base_scalar_mul(
             &self,
             _initial_witness: &mut BTreeMap<Witness, FieldElement>,
             _inputs: &[FunctionInput],
             _outputs: &[Witness],
         ) -> Result<OpcodeResolution, OpcodeResolutionError> {
-            {
-                panic!("Path not trodden by this test")
-            }
+            panic!("Path not trodden by this test")
         }
         fn keccak256(
             &self,
             _initial_witness: &mut BTreeMap<Witness, FieldElement>,
             _inputs: &[FunctionInput],
             _outputs: &[Witness],
         ) -> Result<OpcodeResolution, OpcodeResolutionError> {
-            {
-                panic!("Path not trodden by this test")
-            }
+            panic!("Path not trodden by this test")
         }
     }
 

acvm/src/pwg/blackbox.rs

@@ -61,7 +61,8 @@ pub(crate) fn solve(
             backend.xor(initial_witness, inputs, outputs)
         }
         BlackBoxFuncCall { name: BlackBoxFunc::RANGE, inputs, outputs } => {
-            backend.range(initial_witness, inputs, outputs)
+            assert!(outputs.is_empty());
+            backend.range(initial_witness, inputs)
         }
         BlackBoxFuncCall { name: BlackBoxFunc::SHA256, inputs, outputs } => {
             backend.sha256(initial_witness, inputs, outputs)

acvm/src/pwg/hash.rs

@@ -1,4 +1,4 @@
-use acir::{circuit::opcodes::BlackBoxFuncCall, native_types::Witness, FieldElement};
+use acir::{circuit::opcodes::FunctionInput, native_types::Witness, FieldElement};
 use blake2::{Blake2s256, Digest};
 use sha2::Sha256;
 use sha3::Keccak256;
@@ -10,11 +10,12 @@ use super::{insert_value, witness_to_value};
 
 pub fn blake2s256(
     initial_witness: &mut BTreeMap<Witness, FieldElement>,
-    func_call: &BlackBoxFuncCall,
+    inputs: &[FunctionInput],
+    outputs: &[Witness],
 ) -> Result<OpcodeResolution, OpcodeResolutionError> {
-    let hash = generic_hash_256::<Blake2s256>(initial_witness, func_call)?;
+    let hash = generic_hash_256::<Blake2s256>(initial_witness, inputs)?;
 
-    for (output_witness, value) in func_call.outputs.iter().zip(hash.iter()) {
+    for (output_witness, value) in outputs.iter().zip(hash.iter()) {
         insert_value(
             output_witness,
             FieldElement::from_be_bytes_reduce(&[*value]),
@@ -27,11 +28,12 @@ pub fn blake2s256(
 
 pub fn sha256(
     initial_witness: &mut BTreeMap<Witness, FieldElement>,
-    func_call: &BlackBoxFuncCall,
+    inputs: &[FunctionInput],
+    outputs: &[Witness],
 ) -> Result<OpcodeResolution, OpcodeResolutionError> {
-    let hash = generic_hash_256::<Sha256>(initial_witness, func_call)?;
+    let hash = generic_hash_256::<Sha256>(initial_witness, inputs)?;
 
-    for (output_witness, value) in func_call.outputs.iter().zip(hash.iter()) {
+    for (output_witness, value) in outputs.iter().zip(hash.iter()) {
         insert_value(
             output_witness,
             FieldElement::from_be_bytes_reduce(&[*value]),
@@ -44,11 +46,12 @@ pub fn sha256(
 
 pub fn keccak256(
     initial_witness: &mut BTreeMap<Witness, FieldElement>,
-    func_call: &BlackBoxFuncCall,
+    inputs: &[FunctionInput],
+    outputs: &[Witness],
 ) -> Result<OpcodeResolution, OpcodeResolutionError> {
-    let hash = generic_hash_256::<Keccak256>(initial_witness, func_call)?;
+    let hash = generic_hash_256::<Keccak256>(initial_witness, inputs)?;
 
-    for (output_witness, value) in func_call.outputs.iter().zip(hash.iter()) {
+    for (output_witness, value) in outputs.iter().zip(hash.iter()) {
         insert_value(
             output_witness,
             FieldElement::from_be_bytes_reduce(&[*value]),
@@ -61,24 +64,25 @@ pub fn keccak256(
 
 pub fn hash_to_field_128_security(
     initial_witness: &mut BTreeMap<Witness, FieldElement>,
-    func_call: &BlackBoxFuncCall,
+    inputs: &[FunctionInput],
+    outputs: &[Witness],
 ) -> Result<OpcodeResolution, OpcodeResolutionError> {
-    let hash = generic_hash_256::<Blake2s256>(initial_witness, func_call)?;
+    let hash = generic_hash_256::<Blake2s256>(initial_witness, inputs)?;
 
     let reduced_res = FieldElement::from_be_bytes_reduce(&hash);
-    insert_value(&func_call.outputs[0], reduced_res, initial_witness)?;
+    insert_value(&outputs[0], reduced_res, initial_witness)?;
 
     Ok(OpcodeResolution::Solved)
 }
 
 fn generic_hash_256<D: Digest>(
     initial_witness: &mut BTreeMap<Witness, FieldElement>,
-    func_call: &BlackBoxFuncCall,
+    inputs: &[FunctionInput],
 ) -> Result<[u8; 32], OpcodeResolutionError> {
     let mut hasher = D::new();
 
     // Read witness assignments into hasher.
-    for input in func_call.inputs.iter() {
+    for input in inputs.iter() {
         let witness = input.witness;
         let num_bits = input.num_bits as usize;
 

acvm/src/pwg/logic.rs

@@ -1,43 +1,46 @@
 use super::{insert_value, witness_to_value};
 use crate::{pwg::OpcodeResolution, OpcodeResolutionError};
-use acir::{circuit::opcodes::BlackBoxFuncCall, native_types::Witness, FieldElement};
+use acir::{circuit::opcodes::FunctionInput, native_types::Witness, FieldElement};
 use std::collections::BTreeMap;
 
 /// Solves a [`BlackBoxFunc::And`][acir::circuit::black_box_functions::BlackBoxFunc::AND] opcode and inserts
 /// the result into the supplied witness map
 pub fn and(
     initial_witness: &mut BTreeMap<Witness, FieldElement>,
-    gate: &BlackBoxFuncCall,
+    inputs: &[FunctionInput],
+    outputs: &[Witness],
 ) -> Result<OpcodeResolution, OpcodeResolutionError> {
-    let (a, b, result, num_bits) = extract_input_output(gate);
+    let (a, b, result, num_bits) = extract_input_output(inputs, outputs);
     solve_logic_gate(initial_witness, &a, &b, result, |left, right| left.and(right, num_bits))
 }
 
 /// Solves a [`BlackBoxFunc::XOR`][acir::circuit::black_box_functions::BlackBoxFunc::XOR] opcode and inserts
 /// the result into the supplied witness map
 pub fn xor(
     initial_witness: &mut BTreeMap<Witness, FieldElement>,
-    gate: &BlackBoxFuncCall,
+    inputs: &[FunctionInput],
+    outputs: &[Witness],
 ) -> Result<OpcodeResolution, OpcodeResolutionError> {
-    let (a, b, result, num_bits) = extract_input_output(gate);
+    let (a, b, result, num_bits) = extract_input_output(inputs, outputs);
     solve_logic_gate(initial_witness, &a, &b, result, |left, right| left.xor(right, num_bits))
 }
 
 // TODO: Is there somewhere else that we can put this?
 // TODO: extraction methods are needed for some opcodes like logic and range
 pub(crate) fn extract_input_output(
-    bb_func_call: &BlackBoxFuncCall,
+    inputs: &[FunctionInput],
+    outputs: &[Witness],
 ) -> (Witness, Witness, Witness, u32) {
-    let a = &bb_func_call.inputs[0];
-    let b = &bb_func_call.inputs[1];
-    let result = &bb_func_call.outputs[0];
+    let a = &inputs[0];
+    let b = &inputs[1];
+    let result = outputs[0];
 
     // The num_bits variable should be the same for all witnesses
     assert_eq!(a.num_bits, b.num_bits, "number of bits specified for each input must be the same");
 
     let num_bits = a.num_bits;
 
-    (a.witness, b.witness, *result, num_bits)
+    (a.witness, b.witness, result, num_bits)
 }
 
 /// Derives the rest of the witness based on the initial low level variables

acvm/src/pwg/range.rs

@@ -1,10 +1,10 @@
 use crate::{pwg::witness_to_value, pwg::OpcodeResolution, OpcodeResolutionError};
-use acir::{circuit::opcodes::BlackBoxFuncCall, native_types::Witness, BlackBoxFunc, FieldElement};
+use acir::{circuit::opcodes::FunctionInput, native_types::Witness, BlackBoxFunc, FieldElement};
 use std::collections::BTreeMap;
 
 pub fn solve_range_opcode(
     initial_witness: &mut BTreeMap<Witness, FieldElement>,
-    func_call: &BlackBoxFuncCall,
+    inputs: &[FunctionInput],
 ) -> Result<OpcodeResolution, OpcodeResolutionError> {
     // TODO: this consistency check can be moved to a general function
     let defined_input_size = BlackBoxFunc::RANGE
@@ -13,7 +13,7 @@ pub fn solve_range_opcode(
         .fixed_size()
         .expect("infallible: input for range gate is fixed");
 
-    let num_arguments = func_call.inputs.len();
+    let num_arguments = inputs.len();
     if num_arguments != defined_input_size as usize {
         return Err(OpcodeResolutionError::IncorrectNumFunctionArguments(
             defined_input_size as usize,
@@ -25,7 +25,7 @@ pub fn solve_range_opcode(
     // For the range constraint, we know that the input size should be one
     assert_eq!(defined_input_size, 1);
 
-    let input = func_call.inputs.first().expect("infallible: checked that input size is 1");
+    let input = inputs.first().expect("infallible: checked that input size is 1");
 
     let w_value = witness_to_value(initial_witness, input.witness)?;
     if w_value.num_bits() > input.num_bits {

acvm/src/pwg/signature/ecdsa.rs

@@ -1,13 +1,14 @@
-use acir::{circuit::opcodes::BlackBoxFuncCall, native_types::Witness, FieldElement};
+use acir::{circuit::opcodes::FunctionInput, native_types::Witness, FieldElement};
 use std::collections::BTreeMap;
 
 use crate::{pwg::witness_to_value, pwg::OpcodeResolution, OpcodeResolutionError};
 
 pub fn secp256k1_prehashed(
     initial_witness: &mut BTreeMap<Witness, FieldElement>,
-    gadget_call: &BlackBoxFuncCall,
+    inputs: &[FunctionInput],
+    outputs: &[Witness],
 ) -> Result<OpcodeResolution, OpcodeResolutionError> {
-    let mut inputs_iter = gadget_call.inputs.iter();
+    let mut inputs_iter = inputs.iter();
 
     let mut pub_key_x = [0u8; 32];
     for (i, pkx) in pub_key_x.iter_mut().enumerate() {
@@ -50,7 +51,7 @@ pub fn secp256k1_prehashed(
         ecdsa_secp256k1::verify_prehashed(&hashed_message, &pub_key_x, &pub_key_y, &signature)
             .is_ok();
 
-    initial_witness.insert(gadget_call.outputs[0], FieldElement::from(result));
+    initial_witness.insert(outputs[0], FieldElement::from(result));
     Ok(OpcodeResolution::Solved)
 }