chore!: Remove partial backend feature (#3805)

# Description

Related to #3772 

## Problem\*

Resolves <!-- Link to GitHub Issue -->

## Summary\*



## Additional Context



## Documentation\*

Check one:
- [ ] No documentation needed.
- [ ] Documentation included in this PR.
- [ ] **[Exceptional Case]** Documentation to be submitted in a separate
PR.

# PR Checklist\*

- [ ] I have tested the changes locally.
- [ ] I have formatted the changes with [Prettier](https://prettier.io/)
and/or `cargo fmt` on default settings.

---------

Co-authored-by: Tom French <15848336+TomAFrench@users.noreply.github.com>
Co-authored-by: TomAFrench <tom@tomfren.ch>

.github/workflows/publish-acvm.yml

@@ -51,12 +51,6 @@ jobs:
         env:
           CARGO_REGISTRY_TOKEN: ${{ secrets.ACVM_CRATES_IO_TOKEN }}
 
-      - name: Publish acvm_stdlib
-        run: |
-          cargo publish --package acvm_stdlib
-        env:
-          CARGO_REGISTRY_TOKEN: ${{ secrets.ACVM_CRATES_IO_TOKEN }}
-
       - name: Publish brillig_vm
         run: |
           cargo publish --package brillig_vm

Cargo.toml

@@ -28,7 +28,6 @@ members = [
     "acvm-repo/acir",
     "acvm-repo/acvm",
     "acvm-repo/acvm_js",
-    "acvm-repo/stdlib",
     "acvm-repo/brillig",
     "acvm-repo/brillig_vm",
     "acvm-repo/blackbox_solver",

acvm-repo/acir/src/circuit/black_box_functions.rs

@@ -1,8 +1,5 @@
 //! Black box functions are ACIR opcodes which rely on backends implementing support for specialized constraints.
 //! This makes certain zk-snark unfriendly computations cheaper than if they were implemented in more basic constraints.
-//!
-//! It is possible to fallback to less efficient implementations written in ACIR in some cases.
-//! These are implemented inside the ACVM stdlib.
 
 use serde::{Deserialize, Serialize};
 #[cfg(test)]

acvm-repo/acir/src/circuit/opcodes.rs

@@ -33,21 +33,6 @@ pub enum Opcode {
     },
 }
 
-#[derive(Clone, PartialEq, Eq, Debug)]
-pub enum UnsupportedMemoryOpcode {
-    MemoryOp,
-    MemoryInit,
-}
-
-impl std::fmt::Display for UnsupportedMemoryOpcode {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        match self {
-            UnsupportedMemoryOpcode::MemoryOp => write!(f, "MemoryOp"),
-            UnsupportedMemoryOpcode::MemoryInit => write!(f, "MemoryInit"),
-        }
-    }
-}
-
 impl Opcode {
     // TODO We can add a domain separator by doing something like:
     // TODO concat!("directive:", directive.name)
@@ -62,17 +47,6 @@ impl Opcode {
         }
     }
 
-    pub fn unsupported_opcode(&self) -> UnsupportedMemoryOpcode {
-        match self {
-            Opcode::MemoryOp { .. } => UnsupportedMemoryOpcode::MemoryOp,
-            Opcode::MemoryInit { .. } => UnsupportedMemoryOpcode::MemoryInit,
-            Opcode::BlackBoxFuncCall(_) => {
-                unreachable!("Unsupported Blackbox function should not be reported here")
-            }
-            _ => unreachable!("Opcode is supported"),
-        }
-    }
-
     pub fn is_arithmetic(&self) -> bool {
         matches!(self, Opcode::Arithmetic(_))
     }

acvm-repo/acvm/Cargo.toml

@@ -19,28 +19,23 @@ thiserror.workspace = true
 log.workspace = true
 
 acir.workspace = true
-stdlib.workspace = true
 brillig_vm.workspace = true
 acvm_blackbox_solver.workspace = true
 
 indexmap = "1.7.0"
 
 [features]
-default = ["bn254", "testing"]
+default = ["bn254"]
 bn254 = [
     "acir/bn254",
-    "stdlib/bn254",
     "brillig_vm/bn254",
     "acvm_blackbox_solver/bn254",
 ]
 bls12_381 = [
     "acir/bls12_381",
-    "stdlib/bls12_381",
     "brillig_vm/bls12_381",
     "acvm_blackbox_solver/bls12_381",
 ]
-testing = ["stdlib/testing", "unstable-fallbacks"]
-unstable-fallbacks = []
 
 [dev-dependencies]
 rand = "0.8.5"

acvm-repo/acvm/src/compiler/mod.rs

@@ -1,10 +1,6 @@
 use std::collections::HashMap;
 
-use acir::{
-    circuit::{opcodes::UnsupportedMemoryOpcode, Circuit, Opcode, OpcodeLocation},
-    BlackBoxFunc,
-};
-use thiserror::Error;
+use acir::circuit::{Circuit, OpcodeLocation};
 
 use crate::Language;
 
@@ -17,14 +13,6 @@ use optimizers::optimize_internal;
 pub use transformers::transform;
 use transformers::transform_internal;
 
-#[derive(PartialEq, Eq, Debug, Error)]
-pub enum CompileError {
-    #[error("The blackbox function {0} is not supported by the backend and acvm does not have a fallback implementation")]
-    UnsupportedBlackBox(BlackBoxFunc),
-    #[error("The opcode {0} is not supported by the backend and acvm does not have a fallback implementation")]
-    UnsupportedMemoryOpcode(UnsupportedMemoryOpcode),
-}
-
 /// This module moves and decomposes acir opcodes. The transformation map allows consumers of this module to map
 /// metadata they had about the opcodes to the new opcode structure generated after the transformation.
 #[derive(Debug)]
@@ -81,19 +69,15 @@ fn transform_assert_messages(
 }
 
 /// Applies [`ProofSystemCompiler`][crate::ProofSystemCompiler] specific optimizations to a [`Circuit`].
-pub fn compile(
-    acir: Circuit,
-    np_language: Language,
-    is_opcode_supported: impl Fn(&Opcode) -> bool,
-) -> Result<(Circuit, AcirTransformationMap), CompileError> {
+pub fn compile(acir: Circuit, np_language: Language) -> (Circuit, AcirTransformationMap) {
     let (acir, acir_opcode_positions) = optimize_internal(acir);
 
     let (mut acir, acir_opcode_positions) =
-        transform_internal(acir, np_language, is_opcode_supported, acir_opcode_positions)?;
+        transform_internal(acir, np_language, acir_opcode_positions);
 
     let transformation_map = AcirTransformationMap::new(acir_opcode_positions);
 
     acir.assert_messages = transform_assert_messages(acir.assert_messages, &transformation_map);
 
-    Ok((acir, transformation_map))
+    (acir, transformation_map)
 }

acvm-repo/acvm/src/compiler/transformers/mod.rs

@@ -8,33 +8,27 @@ use indexmap::IndexMap;
 use crate::Language;
 
 mod csat;
-mod fallback;
 mod r1cs;
 
 pub(crate) use csat::CSatTransformer;
-pub(crate) use fallback::FallbackTransformer;
 pub(crate) use r1cs::R1CSTransformer;
 
-use super::{transform_assert_messages, AcirTransformationMap, CompileError};
+use super::{transform_assert_messages, AcirTransformationMap};
 
 /// Applies [`ProofSystemCompiler`][crate::ProofSystemCompiler] specific optimizations to a [`Circuit`].
-pub fn transform(
-    acir: Circuit,
-    np_language: Language,
-    is_opcode_supported: impl Fn(&Opcode) -> bool,
-) -> Result<(Circuit, AcirTransformationMap), CompileError> {
+pub fn transform(acir: Circuit, np_language: Language) -> (Circuit, AcirTransformationMap) {
     // Track original acir opcode positions throughout the transformation passes of the compilation
     // by applying the modifications done to the circuit opcodes and also to the opcode_positions (delete and insert)
     let acir_opcode_positions = acir.opcodes.iter().enumerate().map(|(i, _)| i).collect();
 
     let (mut acir, acir_opcode_positions) =
-        transform_internal(acir, np_language, is_opcode_supported, acir_opcode_positions)?;
+        transform_internal(acir, np_language, acir_opcode_positions);
 
     let transformation_map = AcirTransformationMap::new(acir_opcode_positions);
 
     acir.assert_messages = transform_assert_messages(acir.assert_messages, &transformation_map);
 
-    Ok((acir, transformation_map))
+    (acir, transformation_map)
 }
 
 /// Applies [`ProofSystemCompiler`][crate::ProofSystemCompiler] specific optimizations to a [`Circuit`].
@@ -43,19 +37,14 @@ pub fn transform(
 pub(super) fn transform_internal(
     acir: Circuit,
     np_language: Language,
-    is_opcode_supported: impl Fn(&Opcode) -> bool,
     acir_opcode_positions: Vec<usize>,
-) -> Result<(Circuit, Vec<usize>), CompileError> {
+) -> (Circuit, Vec<usize>) {
     log::trace!("Start circuit transformation");
 
-    // Fallback transformer pass
-    let (acir, acir_opcode_positions) =
-        FallbackTransformer::transform(acir, is_opcode_supported, acir_opcode_positions)?;
-
     let mut transformer = match &np_language {
         crate::Language::R1CS => {
             let transformer = R1CSTransformer::new(acir);
-            return Ok((transformer.transform(), acir_opcode_positions));
+            return (transformer.transform(), acir_opcode_positions);
         }
         crate::Language::PLONKCSat { width } => {
             let mut csat = CSatTransformer::new(*width);
@@ -219,5 +208,5 @@ pub(super) fn transform_internal(
 
     log::trace!("Finish circuit transformation");
 
-    Ok((acir, new_acir_opcode_positions))
+    (acir, new_acir_opcode_positions)
 }