Merge pull request #2369 from AleoHQ/fix/finalize-cost-calculation

[Fix/Optimize] Fixes and optimizes calculation of execution cost.

ledger/src/tests.rs

@@ -28,7 +28,7 @@ use indexmap::IndexMap;
 use ledger_block::{ConfirmedTransaction, Rejected, Transaction};
 use ledger_committee::{Committee, MIN_VALIDATOR_STAKE};
 use ledger_store::{helpers::memory::ConsensusMemory, ConsensusStore};
-use synthesizer::{prelude::cost_in_microcredits, program::Program, vm::VM, Stack};
+use synthesizer::{program::Program, vm::VM, Stack};
 
 #[test]
 fn test_load() {
@@ -1525,15 +1525,9 @@ fn test_deployment_exceeding_max_transaction_spend() {
         ))
         .unwrap();
 
-        // Initialize a stack for the program.
-        let stack = Stack::<CurrentNetwork>::new(&ledger.vm().process().read(), &program).unwrap();
-
-        // Check the finalize cost.
-        let finalize_cost = cost_in_microcredits(&stack, &Identifier::from_str("foo").unwrap()).unwrap();
-
-        // If the finalize cost exceeds the maximum transaction spend, assign the program to the exceeding program and break.
-        // Otherwise, assign the program to the allowed program and continue.
-        if finalize_cost > <CurrentNetwork as Network>::TRANSACTION_SPEND_LIMIT {
+        // Attempt to initialize a `Stack` for the program.
+        // If this fails, then by `Stack::initialize` the finalize cost exceeds the `TRANSACTION_SPEND_LIMIT`.
+        if Stack::<CurrentNetwork>::new(&ledger.vm().process().read(), &program).is_err() {
             exceeding_program = Some(program);
             break;
         } else {
@@ -1567,9 +1561,9 @@ fn test_deployment_exceeding_max_transaction_spend() {
     // Check that the program exists in the VM.
     assert!(ledger.vm().contains_program(allowed_program.id()));
 
-    // Deploy the exceeding program.
-    let deployment = ledger.vm().deploy(&private_key, &exceeding_program, None, 0, None, rng).unwrap();
+    // Attempt to deploy the exceeding program.
+    let result = ledger.vm().deploy(&private_key, &exceeding_program, None, 0, None, rng);
 
-    // Verify the deployment transaction.
-    assert!(ledger.vm().check_transaction(&deployment, None, rng).is_err());
+    // Check that the deployment failed.
+    assert!(result.is_err());
 }

synthesizer/process/src/cost.rs

@@ -60,21 +60,11 @@ pub fn execution_cost<N: Network>(process: &Process<N>, execution: &Execution<N>
     // Compute the storage cost in microcredits.
     let storage_cost = execution.size_in_bytes()?;
 
-    // Compute the finalize cost in microcredits.
-    let mut finalize_cost = 0u64;
-    // Iterate over the transitions to accumulate the finalize cost.
-    for transition in execution.transitions() {
-        // Retrieve the program ID and function name.
-        let (program_id, function_name) = (transition.program_id(), transition.function_name());
-        // Retrieve the finalize cost.
-        let cost = cost_in_microcredits(process.get_stack(program_id)?, function_name)?;
-        // Accumulate the finalize cost.
-        if cost > 0 {
-            finalize_cost = finalize_cost
-                .checked_add(cost)
-                .ok_or(anyhow!("The finalize cost computation overflowed on '{program_id}/{function_name}'"))?;
-        }
-    }
+    // Get the root transition.
+    let transition = execution.peek()?;
+
+    // Get the finalize cost for the root transition.
+    let finalize_cost = process.get_stack(transition.program_id())?.get_finalize_cost(transition.function_name())?;
 
     // Compute the total cost in microcredits.
     let total_cost = storage_cost
@@ -370,10 +360,21 @@ pub fn cost_in_microcredits<N: Network>(stack: &Stack<N>, function_name: &Identi
         Command::Position(_) => Ok(100),
     };
 
+    // Get the cost of finalizing all futures.
+    let mut future_cost = 0u64;
+    for input in finalize.inputs() {
+        if let FinalizeType::Future(future) = input.finalize_type() {
+            // Get the external stack for the future.
+            let stack = stack.get_external_stack(future.program_id())?;
+            // Accumulate the finalize cost of the future.
+            future_cost = future_cost
+                .checked_add(stack.get_finalize_cost(future.resource())?)
+                .ok_or(anyhow!("Finalize cost overflowed"))?;
+        }
+    }
+
     // Aggregate the cost of all commands in the program.
-    finalize
-        .commands()
-        .iter()
-        .map(cost)
-        .try_fold(0u64, |acc, res| res.and_then(|x| acc.checked_add(x).ok_or(anyhow!("Finalize cost overflowed"))))
+    finalize.commands().iter().map(cost).try_fold(future_cost, |acc, res| {
+        res.and_then(|x| acc.checked_add(x).ok_or(anyhow!("Finalize cost overflowed")))
+    })
 }

synthesizer/process/src/stack/helpers/initialize.rs

@@ -28,6 +28,7 @@ impl<N: Network> Stack<N> {
             proving_keys: Default::default(),
             verifying_keys: Default::default(),
             number_of_calls: Default::default(),
+            finalize_costs: Default::default(),
             program_depth: 0,
         };
 
@@ -82,6 +83,17 @@ impl<N: Network> Stack<N> {
             );
             // Add the number of calls to the stack.
             stack.number_of_calls.insert(*function.name(), num_calls);
+
+            // Get the finalize cost.
+            let finalize_cost = cost_in_microcredits(&stack, function.name())?;
+            // Check that the finalize cost does not exceed the maximum.
+            ensure!(
+                finalize_cost <= N::TRANSACTION_SPEND_LIMIT,
+                "Finalize block '{}' has a cost '{finalize_cost}' which exceeds the transaction spend limit '{}'",
+                function.name(),
+                N::TRANSACTION_SPEND_LIMIT
+            );
+            stack.finalize_costs.insert(*function.name(), finalize_cost);
         }
 
         // Return the stack.

synthesizer/process/src/stack/mod.rs

@@ -36,7 +36,7 @@ mod evaluate;
 mod execute;
 mod helpers;
 
-use crate::{traits::*, CallMetrics, Process, Trace};
+use crate::{cost_in_microcredits, traits::*, CallMetrics, Process, Trace};
 use console::{
     account::{Address, PrivateKey},
     network::prelude::*,
@@ -187,6 +187,8 @@ pub struct Stack<N: Network> {
     verifying_keys: Arc<RwLock<IndexMap<Identifier<N>, VerifyingKey<N>>>>,
     /// The mapping of function names to the number of calls.
     number_of_calls: IndexMap<Identifier<N>, usize>,
+    /// The mapping of function names to finalize cost.
+    finalize_costs: IndexMap<Identifier<N>, u64>,
     /// The program depth.
     program_depth: usize,
 }
@@ -274,6 +276,15 @@ impl<N: Network> StackProgram<N> for Stack<N> {
         external_program.get_record(locator.resource())
     }
 
+    /// Returns the expected finalize cost for the given function name.
+    #[inline]
+    fn get_finalize_cost(&self, function_name: &Identifier<N>) -> Result<u64> {
+        self.finalize_costs
+            .get(function_name)
+            .copied()
+            .ok_or_else(|| anyhow!("Function '{function_name}' does not exist"))
+    }
+
     /// Returns the function with the given function name.
     #[inline]
     fn get_function(&self, function_name: &Identifier<N>) -> Result<Function<N>> {

synthesizer/process/src/tests/test_execute.rs

@@ -16,6 +16,7 @@ use crate::{
     traits::{StackEvaluate, StackExecute},
     CallStack,
     Process,
+    Stack,
     Trace,
 };
 use circuit::{network::AleoV0, Aleo};
@@ -2611,3 +2612,32 @@ fn test_max_imports() {
     ));
     assert!(result.is_err());
 }
+
+#[test]
+fn test_program_exceeding_transaction_spend_limit() {
+    // Construct a finalize body whose finalize cost is excessively large.
+    let finalize_body = (0..<CurrentNetwork as Network>::MAX_COMMANDS)
+        .map(|i| format!("hash.bhp256 0field into r{i} as field;"))
+        .collect::<Vec<_>>()
+        .join("\n");
+    // Construct the program.
+    let program = Program::from_str(&format!(
+        r"program test_max_spend_limit.aleo;
+      function foo:
+      async foo into r0;
+      output r0 as test_max_spend_limit.aleo/foo.future;
+      finalize foo:{finalize_body}",
+    ))
+    .unwrap();
+
+    // Initialize a `Process`.
+    let mut process = Process::<CurrentNetwork>::load().unwrap();
+
+    // Attempt to add the program to the process, which should fail.
+    let result = process.add_program(&program);
+    assert!(result.is_err());
+
+    // Attempt to initialize a `Stack` directly with the program, which should fail.
+    let result = Stack::initialize(&process, &program);
+    assert!(result.is_err());
+}

synthesizer/process/src/verify_deployment.rs

@@ -33,16 +33,6 @@ impl<N: Network> Process<N> {
         let stack = Stack::new(self, deployment.program())?;
         lap!(timer, "Compute the stack");
 
-        // Ensure that each finalize block does not exceed the `TRANSACTION_SPEND_LIMIT`.
-        for (function_name, _) in deployment.program().functions() {
-            let finalize_cost = cost_in_microcredits(&stack, function_name)?;
-            ensure!(
-                finalize_cost <= N::TRANSACTION_SPEND_LIMIT,
-                "Finalize block '{function_name}' has a cost '{finalize_cost}' which exceeds the transaction spend limit '{}'",
-                N::TRANSACTION_SPEND_LIMIT
-            );
-        }
-
         // Ensure the verifying keys are well-formed and the certificates are valid.
         let verification = stack.verify_deployment::<A, R>(deployment, rng);
         lap!(timer, "Verify the deployment");

synthesizer/program/src/traits/stack_and_registers.rs

@@ -80,6 +80,9 @@ pub trait StackProgram<N: Network> {
     /// Returns `true` if the stack contains the external record.
     fn get_external_record(&self, locator: &Locator<N>) -> Result<&RecordType<N>>;
 
+    /// Returns the expected finalize cost for the given function name.
+    fn get_finalize_cost(&self, function_name: &Identifier<N>) -> Result<u64>;
+
     /// Returns the function with the given function name.
     fn get_function(&self, function_name: &Identifier<N>) -> Result<Function<N>>;