context.cpp

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#include "barretenberg/vm2/simulation/context.hpp"
 
#include <algorithm>
#include <cstdint>
#include <vector>
 
#include "barretenberg/vm2/common/field.hpp"
#include "barretenberg/vm2/common/memory_types.hpp"
 
namespace bb::avm2::simulation {
 
// Base Context
std::vector<FF> BaseContext::get_returndata(uint32_t rd_offset, uint32_t rd_copy_size)
{
    MemoryInterface& child_memory = get_child_context().get_memory();
    // The amount to rd copy is the minimum of the requested size (with the offset into rd) and the size of the
    // returndata We need to do it over a wider integer type to avoid overflow issues, but the result is guaranteed to
    // be a u32 since last_child_rd_size would have previously been constrained to be u32.
    uint32_t max_read_index = static_cast<uint32_t>(
        std::min(static_cast<uint64_t>(rd_offset) + rd_copy_size, static_cast<uint64_t>(last_child_rd_size)));
 
    std::vector<FF> padded_returndata;
    padded_returndata.reserve(max_read_index - rd_offset);
 
    for (uint32_t i = rd_offset; i < max_read_index; i++) {
        padded_returndata.push_back(child_memory.get(get_last_rd_addr() + i));
    }
    // Resize because relying on default initialization of FF (in reserve) is a potential footgun
    padded_returndata.resize(rd_copy_size, 0);
 
    return padded_returndata;
};
 
uint32_t BaseContext::get_last_child_id() const
{
    if (child_context == nullptr) {
        return 0; // No child context, so no last child id.
    }
    return child_context->get_context_id();
}
 
// Enqueued Context
std::vector<FF> EnqueuedCallContext::get_calldata(uint32_t cd_offset, uint32_t cd_copy_size) const
{
    uint64_t calldata_size = static_cast<uint64_t>(calldata.size());
    // We first take a slice of the data, the most we can slice is the actual size of the data
    uint64_t max_read_index = std::min(static_cast<uint64_t>(cd_offset) + cd_copy_size, calldata_size);
 
    std::vector<FF> padded_calldata;
    padded_calldata.reserve(max_read_index - cd_offset);
 
    for (size_t i = cd_offset; i < max_read_index; i++) {
        padded_calldata.push_back(calldata[i]);
    }
    // Resize because relying on default initialization of FF (in reserve) is a potential footgun
    padded_calldata.resize(cd_copy_size, 0);
 
    return padded_calldata;
};
 
ContextEvent EnqueuedCallContext::serialize_context_event()
{
    return {
        .id = get_context_id(),
        .parent_id = 0,
        .last_child_id = get_last_child_id(),
        .pc = get_pc(),
        .msg_sender = get_msg_sender(),
        .contract_addr = get_address(),
        .bytecode_id = get_bytecode_manager().try_get_bytecode_id().value_or(FF(0)),
        .transaction_fee = get_transaction_fee(),
        .is_static = get_is_static(),
        .parent_cd_addr = 0,
        .parent_cd_size = get_parent_cd_size(),
        .last_child_rd_addr = get_last_rd_addr(),
        .last_child_rd_size = get_last_rd_size(),
        .last_child_success = get_last_success(),
        .gas_used = get_gas_used(),
        .gas_limit = get_gas_limit(),
        .parent_gas_used = get_parent_gas_used(),
        .parent_gas_limit = get_parent_gas_limit(),
        // internal call stack
        .internal_call_id = get_internal_call_stack_manager().get_call_id(),
        .internal_call_return_id = get_internal_call_stack_manager().get_return_call_id(),
        .next_internal_call_id = get_internal_call_stack_manager().get_next_call_id(),
        // Tree States
        .tree_states = merkle_db.get_tree_state(),
        .written_public_data_slots_tree_snapshot = written_public_data_slots_tree.snapshot(),
        // Side Effects
        .side_effect_states = get_side_effect_states(),
        // Phase
        .phase = get_phase(),
    };
};
 
// Nested Context
std::vector<FF> NestedContext::get_calldata(uint32_t cd_offset, uint32_t cd_copy_size) const
{
    // This is the amount of the parent calldata we will read
    // We need to do it over a wider integer type to avoid overflow issues
    // Explicit for clarity
    uint64_t parent_cd_size_u64 = static_cast<uint64_t>(parent_cd_size);
 
    uint64_t max_read_index = std::min(static_cast<uint64_t>(cd_offset) + cd_copy_size, parent_cd_size_u64);
 
    std::vector<FF> padded_calldata;
    padded_calldata.reserve(max_read_index - cd_offset);
 
    for (uint32_t i = cd_offset; i < max_read_index; i++) {
        padded_calldata.push_back(parent_context.get_memory().get(parent_cd_addr + i));
    }
    // Resize because relying on default initialization of FF (in reserve) is a potential footgun
    padded_calldata.resize(cd_copy_size, 0);
 
    return padded_calldata;
};
 
ContextEvent NestedContext::serialize_context_event()
{
    return {
        .id = get_context_id(),
        .parent_id = get_parent_id(),
        .last_child_id = get_last_child_id(),
        .pc = get_pc(),
        .msg_sender = get_msg_sender(),
        .contract_addr = get_address(),
        .bytecode_id = get_bytecode_manager().try_get_bytecode_id().value_or(FF(0)),
        .transaction_fee = get_transaction_fee(),
        .is_static = get_is_static(),
        .parent_cd_addr = parent_cd_addr,
        .parent_cd_size = parent_cd_size,
        .last_child_rd_addr = get_last_rd_addr(),
        .last_child_rd_size = get_last_rd_size(),
        .last_child_success = get_last_success(),
        .gas_used = get_gas_used(),
        .gas_limit = get_gas_limit(),
        .parent_gas_used = get_parent_gas_used(),
        .parent_gas_limit = get_parent_gas_limit(),
        // internal call stack
        .internal_call_id = get_internal_call_stack_manager().get_call_id(),
        .internal_call_return_id = get_internal_call_stack_manager().get_return_call_id(),
        .next_internal_call_id = get_internal_call_stack_manager().get_next_call_id(),
        // Tree states
        .tree_states = merkle_db.get_tree_state(),
        .written_public_data_slots_tree_snapshot = written_public_data_slots_tree.snapshot(),
        // Side Effect
        .side_effect_states = get_side_effect_states(),
        // Phase
        .phase = get_phase(),
    };
};
 
} // namespace bb::avm2::simulation