based on david's

avm-transpiler/src/opcodes.rs

@@ -2,27 +2,20 @@
 /// Keep updated with TS and yellow paper!
 #[derive(Copy, Clone)]
 pub enum AvmOpcode {
-    // Compute
-    // Compute - Arithmetic
     ADD,
     SUB,
     MUL,
     DIV,
-    // Compute - Comparators
     EQ,
     LT,
     LTE,
-    // Compute - Bitwise
     AND,
     OR,
     XOR,
     NOT,
     SHL,
     SHR,
-    // Compute - Type Conversions
     CAST,
-
-    // Execution Environment
     ADDRESS,
     STORAGEADDRESS,
     ORIGIN,
@@ -32,7 +25,6 @@ pub enum AvmOpcode {
     FEEPERL2GAS,
     FEEPERDAGAS,
     CONTRACTCALLDEPTH,
-    // Execution Environment - Globals
     CHAINID,
     VERSION,
     BLOCKNUMBER,
@@ -41,25 +33,17 @@ pub enum AvmOpcode {
     BLOCKL1GASLIMIT,
     BLOCKL2GASLIMIT,
     BLOCKDAGASLIMIT,
-    // Execution Environment - Calldata
     CALLDATACOPY,
-
-    // Machine State
-    // Machine State - Gas
     L1GASLEFT,
     L2GASLEFT,
     DAGASLEFT,
-    // Machine State - Internal Control Flow
     JUMP,
     JUMPI,
     INTERNALCALL,
     INTERNALRETURN,
-    // Machine State - Memory
     SET,
     MOV,
     CMOV,
-
-    // World State
     SLOAD,           // Public Storage
     SSTORE,          // Public Storage
     NOTEHASHEXISTS,  // Notes & Nullifiers
@@ -68,19 +52,13 @@ pub enum AvmOpcode {
     EMITNULLIFIER,   // Notes & Nullifiers
     L1TOL2MSGEXISTS, // Messages
     HEADERMEMBER,    // Archive tree & Headers
-
-    // Accrued Substate
     EMITUNENCRYPTEDLOG,
     SENDL2TOL1MSG,
-
-    // Control Flow - Contract Calls
     CALL,
     STATICCALL,
     DELEGATECALL,
     RETURN,
     REVERT,
-
-    // Gadgets
     KECCAK,
     POSEIDON,
     SHA256,

avm-transpiler/src/transpile.rs

@@ -62,6 +62,7 @@ pub fn brillig_to_avm(brillig: &Brillig) -> Vec<u8> {
                 lhs,
                 rhs,
             } => {
+                assert!(is_integral_bit_size(*bit_size), "BinaryIntOp::{:?} bit_size must be integral, got {:?}", op, bit_size);
                 let avm_opcode = match op {
                     BinaryIntOp::Add => AvmOpcode::ADD,
                     BinaryIntOp::Sub => AvmOpcode::SUB,
@@ -179,7 +180,7 @@ pub fn brillig_to_avm(brillig: &Brillig) -> Vec<u8> {
             BrilligOpcode::Stop { return_data_offset, return_data_size } => {
                 avm_instrs.push(AvmInstruction {
                     opcode: AvmOpcode::RETURN,
-                    indirect: Some(ALL_DIRECT),
+                    indirect: Some(ZEROTH_OPERAND_INDIRECT),
                     operands: vec![
                         AvmOperand::U32 { value: *return_data_offset as u32 },
                         AvmOperand::U32 { value: *return_data_size as u32 },
@@ -238,9 +239,10 @@ fn handle_foreign_call(
     inputs: &Vec<ValueOrArray>,
 ) {
     match function {
+        "avmOpcodeCall" => handle_external_call(avm_instrs, destinations, inputs),
         "amvOpcodeEmitUnencryptedLog" => {
             handle_emit_unencrypted_log(avm_instrs, destinations, inputs)
-        },
+        }
         "avmOpcodeNoteHashExists" => handle_note_hash_exists(avm_instrs, destinations, inputs),
         "avmOpcodeEmitNoteHash" | "avmOpcodeEmitNullifier" => handle_emit_note_hash_or_nullifier(
             function == "avmOpcodeEmitNullifier",
@@ -256,7 +258,7 @@ fn handle_foreign_call(
         }
         "avmOpcodePoseidon" => {
             handle_single_field_hash_instruction(avm_instrs, function, destinations, inputs)
-        },
+        }
         "storageRead" => handle_storage_read(avm_instrs, destinations, inputs),
         "storageWrite" => handle_storage_write(avm_instrs, destinations, inputs),
         // Getters.
@@ -271,6 +273,81 @@ fn handle_foreign_call(
     }
 }
 
+/// Handle an AVM CALL
+/// (an external 'call' brillig foreign call was encountered)
+/// Adds the new instruction to the avm instructions list.
+fn handle_external_call(
+    avm_instrs: &mut Vec<AvmInstruction>,
+    destinations: &Vec<ValueOrArray>,
+    inputs: &Vec<ValueOrArray>,
+) {
+    if destinations.len() != 2 || inputs.len() != 4 {
+        panic!(
+            "Transpiler expects ForeignCall::CALL to have 2 destinations and 4 inputs, got {} and {}.
+            Make sure your call instructions's input/return arrays have static length (`[Field; <size>]`)!",
+            destinations.len(),
+            inputs.len()
+        );
+    }
+    let gas_offset_maybe = inputs[0];
+    let gas_offset = match gas_offset_maybe {
+        ValueOrArray::HeapArray(HeapArray { pointer, size }) => {
+            assert!(size == 3, "Call instruction's gas input should be a HeapArray of size 3 (`[l1Gas, l2Gas, daGas]`)");
+            pointer.0 as u32
+        }
+        ValueOrArray::HeapVector(_) => panic!("Call instruction's gas input must be a HeapArray, not a HeapVector. Make sure you are explicitly defining its size as 3 (`[l1Gas, l2Gas, daGas]`)!"),
+        _ => panic!("Call instruction's gas input should be a HeapArray"),
+    };
+    let address_offset = match &inputs[1] {
+        ValueOrArray::MemoryAddress(offset) => offset.to_usize() as u32,
+        _ => panic!("Call instruction's target address input should be a basic MemoryAddress",),
+    };
+    let args_offset_maybe = inputs[2];
+    let (args_offset, args_size) = match args_offset_maybe {
+        ValueOrArray::HeapArray(HeapArray { pointer, size }) => (pointer.0 as u32, size as u32),
+        ValueOrArray::HeapVector(_) => panic!("Call instruction's args must be a HeapArray, not a HeapVector. Make sure you are explicitly defining its size (`[arg0, arg1, ... argN]`)!"),
+        _ => panic!("Call instruction's args input should be a HeapArray input"),
+    };
+    let temporary_function_selector_offset = match &inputs[3] {
+        ValueOrArray::MemoryAddress(offset) => offset.to_usize() as u32,
+        _ => panic!(
+            "Call instruction's temporary function selector input should be a basic MemoryAddress",
+        ),
+    };
+
+    let ret_offset_maybe = destinations[0];
+    let (ret_offset, ret_size) = match ret_offset_maybe {
+        ValueOrArray::HeapArray(HeapArray { pointer, size }) => (pointer.0 as u32, size as u32),
+        ValueOrArray::HeapVector(_) => panic!("Call instruction's return data must be a HeapArray, not a HeapVector. Make sure you are explicitly defining its size (`let returnData: [Field; <size>] = ...`)!"),
+        _ => panic!("Call instruction's returnData destination should be a HeapArray input"),
+    };
+    let success_offset = match &destinations[1] {
+        ValueOrArray::MemoryAddress(offset) => offset.to_usize() as u32,
+        _ => panic!("Call instruction's success destination should be a basic MemoryAddress",),
+    };
+    avm_instrs.push(AvmInstruction {
+        opcode: AvmOpcode::CALL,
+        indirect: Some(0b01101), // (left to right) selector direct, ret offset INDIRECT, args offset INDIRECT, address offset direct, gas offset INDIRECT
+        operands: vec![
+            AvmOperand::U32 { value: gas_offset },
+            AvmOperand::U32 {
+                value: address_offset,
+            },
+            AvmOperand::U32 { value: args_offset },
+            AvmOperand::U32 { value: args_size },
+            AvmOperand::U32 { value: ret_offset },
+            AvmOperand::U32 { value: ret_size },
+            AvmOperand::U32 {
+                value: success_offset,
+            },
+            AvmOperand::U32 {
+                value: temporary_function_selector_offset,
+            },
+        ],
+        ..Default::default()
+    });
+}
+
 /// Handle an AVM NOTEHASHEXISTS instruction
 /// Adds the new instruction to the avm instructions list.
 fn handle_note_hash_exists(
@@ -327,7 +404,10 @@ fn handle_emit_unencrypted_log(
         [ValueOrArray::MemoryAddress(offset), ValueOrArray::HeapArray(array)] => {
             (offset.to_usize() as u32, array)
         }
-        _ => panic!("Unexpected inputs for ForeignCall::EMITUNENCRYPTEDLOG: {:?}", inputs),
+        _ => panic!(
+            "Unexpected inputs for ForeignCall::EMITUNENCRYPTEDLOG: {:?}",
+            inputs
+        ),
     };
     avm_instrs.push(AvmInstruction {
         opcode: AvmOpcode::EMITUNENCRYPTEDLOG,
@@ -913,6 +993,13 @@ fn map_brillig_pcs_to_avm_pcs(initial_offset: usize, brillig: &Brillig) -> Vec<u
     pc_map
 }
 
+fn is_integral_bit_size(bit_size: u32) -> bool {
+    match bit_size {
+        1 | 8 | 16 | 32 | 64 | 128 => true,
+        _ => false,
+    }
+}
+
 fn tag_from_bit_size(bit_size: u32) -> AvmTypeTag {
     match bit_size {
         1 => AvmTypeTag::UINT8, // temp workaround

noir-projects/aztec-nr/aztec/src/context/avm.nr

@@ -1,5 +1,6 @@
 use dep::protocol_types::{address::{AztecAddress, EthAddress}, constants::L1_TO_L2_MESSAGE_LENGTH};
 use dep::protocol_types::traits::{Serialize};
+use dep::protocol_types::abis::function_selector::FunctionSelector;
 
 // Getters that will be converted by the transpiler into their
 // own opcodes
@@ -80,9 +81,19 @@ impl AVMContext {
     #[oracle(avmOpcodeSendL2ToL1Msg)]
     pub fn send_l2_to_l1_msg(self, recipient: EthAddress, content: Field) {}
 
-    ///////////////////////////////////////////////////////////////////////////
-    // The functions below allow interface-equivalence with PrivateContext
-    ///////////////////////////////////////////////////////////////////////////
+    #[oracle(avmOpcodeCall)]
+    fn call<ARGS_COUNT, RET_SIZE>(
+        self,
+        gas: [Field; 3], // gas allocation: [l1Gas, l2Gas, daGas]
+        address: AztecAddress,
+        args: [Field; ARGS_COUNT],
+        temporary_function_selector: Field
+    ) -> ([Field; RET_SIZE], u8) {}
+    //    ^ return data      ^ success
+
+    ////////////////////////////////////////////////////////////////////////////////
+    // The functions below allow interface-equivalence with current public/private
+    ////////////////////////////////////////////////////////////////////////////////
     pub fn this_address(self) -> AztecAddress {
         self.address()
     }
@@ -107,4 +118,25 @@ impl AVMContext {
         // Cannot nullify pending commitments in AVM, so `nullified_commitment` is not used
         self.emit_nullifier(nullifier);
     }
+
+    pub fn call_public_function<ARGS_COUNT, RET_SIZE>(
+        self: Self,
+        contract_address: AztecAddress,
+        temporary_function_selector: FunctionSelector,
+        args: [Field; ARGS_COUNT]
+    ) -> [Field; RET_SIZE] {
+        let gas = [/*l1Gas*/42, /*l2Gas*/24, /*daGas*/420];
+
+        let results = self.call(
+            gas,
+            contract_address,
+            args,
+            temporary_function_selector.to_field()
+        );
+        let returnData: [Field; RET_SIZE] = results.0;
+        let success: u8 = results.1;
+        assert(success == 1, "Nested call failed!");
+
+        returnData
+    }
 }

noir-projects/noir-contracts/contracts/avm_test_contract/src/main.nr

@@ -2,6 +2,7 @@ contract AvmTest {
     // Libs
     use dep::aztec::state_vars::PublicMutable;
     use dep::aztec::protocol_types::{address::{AztecAddress, EthAddress}, constants::L1_TO_L2_MESSAGE_LENGTH};
+    use dep::aztec::protocol_types::abis::function_selector::FunctionSelector;
     use dep::compressed_string::CompressedString;
 
     // avm lib
@@ -214,4 +215,37 @@ contract AvmTest {
     fn send_l2_to_l1_msg(recipient: EthAddress, content: Field) {
         context.message_portal(recipient, content)
     }
+
+    // Directly call the external call opcode to initiate a nested call to the add function
+    #[aztec(public-vm)]
+    fn raw_nested_call_to_add(argA: Field, argB: Field) -> pub Field {
+        let selector = FunctionSelector::from_signature("avm_addArgsReturn(Field,Field)").to_field();
+        let gas = [/*l1Gas*/42, /*l2Gas*/24, /*daGas*/420];
+
+        // Nested call
+        let results = context.call(gas, context.address(), [argA, argB], selector);
+        let returnData: [Field; 1] = results.0;
+        // this explicit size   ^ is necessary to ensure that retSize is compile-time
+        // (ensure the returnData is in a HeapArray not a HeapVector)
+        let success: u8 = results.1;
+
+        assert(success == 1, "Call failed");
+
+        let addResult = returnData[0];
+        addResult
+    }
+
+    // Use the `call_public_function` wrapper to initiate a nested call to the add function
+    #[aztec(public-vm)]
+    fn nested_call_to_add(argA: Field, argB: Field) -> pub Field {
+        let selector = FunctionSelector::from_signature("avm_addArgsReturn(Field,Field)");
+
+        // Nested call using standard context interface function
+        let returnData: [Field; 1] = context.call_public_function(context.address(), selector, [argA, argB]);
+        // this explicit size   ^ is necessary to ensure that retSize is compile-time
+        // (ensure the returnData is in a HeapArray not a HeapVector)
+
+        let addResult = returnData[0];
+        addResult
+    }
 }

noir/noir-repo/compiler/noirc_evaluator/src/brillig/brillig_gen/brillig_block.rs

@@ -831,14 +831,17 @@ impl<'block> BrilligBlock<'block> {
             _ => unreachable!("ICE: array set on non-array"),
         };
 
-        let one = self.brillig_context.make_usize_constant(1_usize.into());
+        // Here we want to compare the reference count against 1.
+        // I don't think we have the bit_size for the reference count available, so I'm hardcoding it.
+        let bit_size = usize::BITS;
+        let one = self.brillig_context.make_constant(1_usize.into(), bit_size);
         let condition = self.brillig_context.allocate_register();
 
         self.brillig_context.binary_instruction(
             reference_count,
             one,
             condition,
-            BrilligBinaryOp::Field { op: BinaryFieldOp::Equals },
+            BrilligBinaryOp::Integer { op: BinaryIntOp::Equals, bit_size },
         );
 
         self.brillig_context.branch_instruction(condition, |ctx, cond| {