feat: merge-train/avm (#20567)

BEGIN_COMMIT_OVERRIDE
docs: fix avm docs - l2 gas is not the same as mana (#20565)
docs: simulator readme typos (#19701)
fix(avm): alu gadget fuzzer serialisation (#19115)
END_COMMIT_OVERRIDE

Author: AztecBot

barretenberg/cpp/src/barretenberg/avm_fuzzer/harness/alu.fuzzer.cpp

@@ -42,8 +42,9 @@ struct AluFuzzerInput {
     MemoryValue a;
     MemoryValue b;
     MemoryValue c = MemoryValue::from_tag(MemoryTag::FF, 0); // Placeholder for result
-    int op_id = 0;                                           // For execution trace alu_op_id
-
+    uint16_t op_id = 0;                                      // For execution trace alu_op_id
+    // We serialise MemoryValues as FF + 1 byte for tag to save 31 bytes per value:
+    static const size_t size = (3 * (sizeof(FF) + 1)) + sizeof(uint16_t);
     // Serialize to buffer
     void to_buffer(uint8_t* buffer) const
     {
@@ -58,7 +59,7 @@ struct AluFuzzerInput {
         buffer += sizeof(FF) + 1;
         write_mem_value(buffer, c);
         buffer += sizeof(FF) + 1;
-        serialize::write(buffer, static_cast<uint16_t>(op_id));
+        serialize::write(buffer, op_id);
     }
 
     static AluFuzzerInput from_buffer(const uint8_t* buffer)
@@ -88,11 +89,11 @@ struct AluFuzzerInput {
 
 extern "C" size_t LLVMFuzzerCustomMutator(uint8_t* data, size_t size, size_t max_size, unsigned int seed)
 {
-    if (size < sizeof(AluFuzzerInput)) {
+    if (size < AluFuzzerInput::size) {
         // Initialize with default input
         AluFuzzerInput input;
         input.to_buffer(data);
-        return sizeof(AluFuzzerInput);
+        return AluFuzzerInput::size;
     }
 
     std::mt19937_64 rng(seed);
@@ -119,7 +120,6 @@ extern "C" size_t LLVMFuzzerCustomMutator(uint8_t* data, size_t size, size_t max
 
     auto random_mem_value_from_tag = [&rng](MemoryTag tag) -> MemoryValue {
         std::uniform_int_distribution<uint64_t> dist(0, std::numeric_limits<uint64_t>::max());
-        // TODO(MW): Use array?
         FF value = FF(dist(rng), dist(rng), dist(rng), dist(rng));
         // Do we want the option of making "invalid tag" values, where the value is out of range for the tag?
         // These aren't currently possible with this function since MemoryValue::from_tag will throw in that case.
@@ -135,9 +135,9 @@ extern "C" size_t LLVMFuzzerCustomMutator(uint8_t* data, size_t size, size_t max
     // Deserialize current input
     AluFuzzerInput input = AluFuzzerInput::from_buffer(data);
 
-    // Choose random ALU operation
+    // Choose random ALU operation (11 possible operations with op_id = 2^index)
     std::uniform_int_distribution<int> dist(0, 11);
-    input.op_id = 1 << dist(rng);
+    input.op_id = static_cast<uint16_t>(1 << dist(rng));
 
     // Choose test case (TODO(MW): what else do we want here?)
     dist = std::uniform_int_distribution<int>(0, 4);
@@ -187,18 +187,18 @@ extern "C" size_t LLVMFuzzerCustomMutator(uint8_t* data, size_t size, size_t max
     // Serialize mutated input back to buffer
     input.to_buffer(data);
 
-    if (max_size > sizeof(AluFuzzerInput)) {
-        return sizeof(AluFuzzerInput);
+    if (max_size > AluFuzzerInput::size) {
+        return AluFuzzerInput::size;
     }
 
-    return sizeof(AluFuzzerInput);
+    return AluFuzzerInput::size;
 }
 
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size)
 {
     using bb::avm2::MemoryValue;
 
-    if (size < sizeof(AluFuzzerInput)) {
+    if (size < AluFuzzerInput::size) {
         info("Input size too small");
         return 0;
     }

yarn-project/simulator/README.md

@@ -12,7 +12,7 @@ It's able to simulate three different types of functions:
 
 Private functions are simulated and proved client-side, and verified client-side in the private kernel circuit.
 
-The public inputs of private functions is defined [here](../stdlib/src/structs/private_circuit_public_inputs.ts).
+The public inputs of private functions are defined [here](../stdlib/src/structs/private_circuit_public_inputs.ts).
 
 They are run with the assistance of a DB oracle that provides any private data requested by the function.
 
@@ -22,17 +22,17 @@ Private functions can call another private function, and can request to call a p
 
 Public functions are simulated and proved on the sequencer side, and verified by the public kernel circuit.
 
-The public inputs of public functions is defined [here](../stdlib/src/structs/avm/avm_circuit_public_inputs.ts).
+The public inputs of public functions are defined [here](../stdlib/src/structs/avm/avm_circuit_public_inputs.ts).
 
 They are run with the assistance of an oracle that provides any value read from the public state tree.
 
-Public functions can call other public function, but no private functions.
+Public functions can call other public functions, but cannot call private functions.
 
 See the specifications of the [Aztec Virtual Machine (AVM) for public execution](./docs/avm/index.md).
 
 ### Unconstrained Functions
 
-Unconstrained functions are useful to extract useful data for users that could produce very large execution traces - such as the summed balance of all a users notes
+Unconstrained functions are useful to extract data for users that could produce very large execution traces - such as the summed balance of all of a user's notes.
 They are not proved, and are simulated client-side.
 
 They are run with the assistance of a DB oracle that provides any private data requested by the function.

yarn-project/simulator/docs/avm/README.md

@@ -39,7 +39,7 @@ public execution requests.
 The AVM:
 * Executes specified public bytecode, instruction by instruction, given some arguments.
 * Meters execution by tracking gas costs per-executed-instruction.
-* Tracks both "mana" (aka L2 gas) and "data availability" gas.
+* Tracks both L2 gas (computation) and DA gas (data availability).
 * Supports nested contract calls and conditional error recovery.
 * Manages access to public state, L1↔L2 messages, public logs, and some limited private state.
 * Finalizes state updates initiated during private execution.

yarn-project/simulator/docs/avm/gas.md

@@ -1,10 +1,10 @@
 # Gas Metering
 
-The AVM tracks gas consumption across two dimensions: **L2 gas** (execution costs, also called **mana**) and **DA gas** (data availability costs).
+The AVM tracks gas consumption across two dimensions: **L2 gas** (execution costs) and **DA gas** (data availability costs). Note that L2 gas is _not_ the same as mana: mana is the higher-level unit of account that incorporates L2 gas, DA gas, and L1 gas costs together.
 
 ## Gas Dimensions
 
-* **L2 Gas** (mana): roughly represents the computational cost of executing (and especially proving) operations.
+* **L2 Gas**: roughly represents the computational cost of executing (and especially proving) operations.
 * **DA Gas**: represents the cost of publishing data to Layer 1 for data availability. This includes:
   - State updates that must be published to L1
   - Emitting logs