perf(svm): reuse constant V5 transfer delegates

programs/svm-spoke/V5_ADAPTER_SPEC.md

@@ -130,6 +130,12 @@ For the configured Spoke program, `v5_deposit_delegate` derives
 `8DWnJFMBTSDYWsUUSqna9tx9LJbU1yUfq7jTiPJDf8sX` with bump 252. Builders must use this PDA as both the approval
 target and the supplied deposit delegate account.
 
+The V5-specific [transfer helper](src/v5/transfer.rs) selects the deposit or fill delegate's constant address, seed and
+bump as one internal combination. It checks the supplied authority against that address and signs the token CPI with
+its canonical seeds, without searching for the PDA again. Both combinations are tested against derivation under the
+configured Spoke program ID; program-ID changes must update those constants together. No caller-supplied bump is
+accepted.
+
 The `v5_fill_delegate` PDA derives `D27f3mVXRL6N3bgja49UWLQu7kt57sy1aZYy7ZEwdxn1` with bump 252. Builders must use it
 as both the approval target and the supplied fill delegate account for every fill, including self-transfers.
 Both deposits and fills rely on the token program to validate delegate authority and allowance during

programs/svm-spoke/src/instructions/v5_adapter/deposit.rs

@@ -5,17 +5,15 @@ use anchor_spl::{
 };
 
 use crate::{
-    constants::{
-        GATEWAY_PROGRAM_ID, MAX_EXCLUSIVITY_PERIOD_SECONDS, V5_DEPOSIT_DELEGATE, V5_DEPOSIT_DELEGATE_SEED,
-        V5_MAGIC_PREFIX,
-    },
+    constants::{GATEWAY_PROGRAM_ID, MAX_EXCLUSIVITY_PERIOD_SECONDS, V5_DEPOSIT_DELEGATE, V5_MAGIC_PREFIX},
     error::CommonError,
     event::FundsDeposited,
-    utils::{get_current_time, transfer_from},
+    utils::get_current_time,
     v5::{
         accounts::find_v5_account,
         codec::{decode_strict, resolve_v5_input_amount, AcrossDepositInput, GatewayContextV1},
         jit::{derive_v5_deposit_id, resolve_v5_deposit_modifications},
+        transfer::{transfer_from, V5TransferDelegate},
     },
 };
 
@@ -65,7 +63,7 @@ pub(super) fn execute_v5_deposit<'info>(
         accounts.token_program,
         input_amount,
         accounts.mint_decimals,
-        V5_DEPOSIT_DELEGATE_SEED,
+        V5TransferDelegate::Deposit,
     )?;
 
     emit_cpi!(FundsDeposited {

programs/svm-spoke/src/instructions/v5_adapter/fill.rs

@@ -2,14 +2,15 @@ use anchor_lang::{prelude::*, solana_program::keccak};
 use anchor_spl::{associated_token::get_associated_token_address_with_program_id, token_interface::TransferChecked};
 
 use crate::{
-    constants::{V5_FILL_DELEGATE, V5_FILL_DELEGATE_SEED, V5_MAGIC_PREFIX},
+    constants::{V5_FILL_DELEGATE, V5_MAGIC_PREFIX},
     error::{CommonError, V5Error},
     event::{FillType, FilledRelay, RelayExecutionEventInfo},
-    utils::{get_current_time, get_relay_hash, transfer_from},
+    utils::{get_current_time, get_relay_hash},
     v5::{
         accounts::find_v5_account,
         codec::{decode_strict, GatewayContextV1, V5FillInput, V5FillJit},
         fill_status::{create_v5_fill_status_account, V5FillStatusPdas},
+        transfer::{transfer_from, V5TransferDelegate},
     },
 };
 
@@ -72,7 +73,7 @@ pub(super) fn execute_v5_fill<'info>(
         accounts.token_program,
         relay.output_amount,
         accounts.mint_decimals,
-        V5_FILL_DELEGATE_SEED,
+        V5TransferDelegate::Fill,
     )?;
 
     // Update the fill status and rent-reclaim metadata; V5 stores its payer PDA as the rent recipient.

programs/svm-spoke/src/utils/mod.rs

@@ -2,10 +2,8 @@ pub mod bitmap_utils;
 pub mod cctp_utils;
 pub mod merkle_proof_utils;
 pub mod testable_utils;
-pub mod transfer_utils;
 
 pub use bitmap_utils::*;
 pub use cctp_utils::*;
 pub use merkle_proof_utils::*;
 pub use testable_utils::*;
-pub use transfer_utils::*;

programs/svm-spoke/src/v5/mod.rs

@@ -1,4 +1,4 @@
-//! Wire, cryptographic, account-validation, and fill-status foundations for the Gateway-facing V5 adapter.
+//! Wire, cryptographic, account-validation, transfer, and fill-status foundations for the Gateway-facing V5 adapter.
 //!
 //! `V5` identifies the Across protocol generation, while `V1` on a context or input variant identifies that
 //! structure's SVM wire-schema revision. Those schemas evolve independently: append a new input variant for a changed
@@ -8,6 +8,7 @@ pub mod accounts;
 pub mod codec;
 pub mod fill_status;
 pub mod jit;
+pub(crate) mod transfer;
 
 #[cfg(test)]
 mod tests;

programs/svm-spoke/src/v5/transfer.rs

@@ -0,0 +1,82 @@
+//! Transfers authorized by the V5 adapter's fixed deposit and fill delegates.
+
+use crate::{
+    constants::{
+        V5_DEPOSIT_DELEGATE, V5_DEPOSIT_DELEGATE_BUMP, V5_DEPOSIT_DELEGATE_SEED, V5_FILL_DELEGATE,
+        V5_FILL_DELEGATE_BUMP, V5_FILL_DELEGATE_SEED,
+    },
+    error::SvmError,
+};
+use anchor_lang::prelude::*;
+use anchor_spl::token_interface::{transfer_checked, TransferChecked};
+
+/// Select a trusted address/seed/bump combination; callers cannot mix delegate components.
+#[derive(Clone, Copy)]
+pub(crate) enum V5TransferDelegate {
+    Deposit,
+    Fill,
+}
+
+impl V5TransferDelegate {
+    fn pda(self) -> (Pubkey, &'static [u8], u8) {
+        match self {
+            Self::Deposit => (V5_DEPOSIT_DELEGATE, V5_DEPOSIT_DELEGATE_SEED, V5_DEPOSIT_DELEGATE_BUMP),
+            Self::Fill => (V5_FILL_DELEGATE, V5_FILL_DELEGATE_SEED, V5_FILL_DELEGATE_BUMP),
+        }
+    }
+}
+
+pub(crate) fn transfer_from<'info>(
+    accounts: TransferChecked<'info>,
+    token_program: AccountInfo<'info>,
+    amount: u64,
+    mint_decimals: u8,
+    delegate: V5TransferDelegate,
+) -> Result<()> {
+    let (delegate, delegate_seed, bump) = delegate.pda();
+    if delegate != accounts.authority.key() {
+        return err!(SvmError::InvalidDelegatePda);
+    }
+
+    let bump_seed = [bump];
+    let signer_seeds: &[&[u8]] = &[delegate_seed, &bump_seed];
+    let signer_seeds = [signer_seeds];
+
+    transfer_checked(CpiContext::new_with_signer(token_program, accounts, &signer_seeds), amount, mint_decimals)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn transfer_delegate_variants_select_their_expected_pdas() {
+        assert_eq!(
+            V5TransferDelegate::Deposit.pda(),
+            (V5_DEPOSIT_DELEGATE, V5_DEPOSIT_DELEGATE_SEED, V5_DEPOSIT_DELEGATE_BUMP)
+        );
+        assert_eq!(V5TransferDelegate::Fill.pda(), (V5_FILL_DELEGATE, V5_FILL_DELEGATE_SEED, V5_FILL_DELEGATE_BUMP));
+    }
+
+    #[test]
+    fn wrong_transfer_authority_is_rejected_before_cpi() {
+        for delegate in [V5TransferDelegate::Deposit, V5TransferDelegate::Fill] {
+            // Include the other canonical delegate: a valid Spoke PDA is insufficient for the wrong operation.
+            for authority in [Pubkey::new_unique(), V5_DEPOSIT_DELEGATE, V5_FILL_DELEGATE] {
+                if authority == delegate.pda().0 {
+                    continue;
+                }
+                let mut lamports = 0;
+                let owner = Pubkey::default();
+                let info = AccountInfo::new(&authority, false, false, &mut lamports, &mut [], &owner, false, 0);
+                let accounts = TransferChecked {
+                    from: info.clone(),
+                    mint: info.clone(),
+                    to: info.clone(),
+                    authority: info.clone(),
+                };
+                assert_eq!(transfer_from(accounts, info, 1, 6, delegate), Err(error!(SvmError::InvalidDelegatePda)));
+            }
+        }
+    }
+}

test/svm-gateway/README.md

@@ -75,9 +75,9 @@ Every recorded bump is already canonical for its seeds; 255 simply means the fir
 | ---------------- | ------------------------: | ------------------------: | --------------------: |
 | legacy-deposit   |                    34,707 |                    31,707 |                32,017 |
 | legacy-fill      |                    41,021 |                    38,021 |                38,331 |
-| v5-deposit       |                    73,516 |                    67,516 |                80,155 |
-| v5-external-fill |                    84,564 |                    78,564 |                90,893 |
-| v5-inplace-fill  |                    91,841 |                    87,341 |                99,670 |
+| v5-deposit       |                    67,469 |                    61,469 |                74,108 |
+| v5-external-fill |                    78,518 |                    72,518 |                84,847 |
+| v5-inplace-fill  |                    85,795 |                    81,295 |                93,624 |
 
 To reproduce the normalization from each `baseline.json` row, define `d(bump) = 255 - bump` and subtract 1,500 times
 the following sum from `execution`:
@@ -121,6 +121,10 @@ different `SVM_CU_OUTPUT` directories and compare `measurements` and program/run
 slots and temporary paths in raw receipts naturally vary. Before committing an updated snapshot, run
 `yarn prettier --write test/svm-gateway/cu/baseline.json`.
 
+For the constant-delegate optimization's per-fixture CU comparison, see
+[PR #1573](https://github.com/across-protocol/contracts/pull/1573)
+([issue #1569](https://github.com/across-protocol/contracts/issues/1569)).
+
 ## Conformance suite
 
 Run `yarn test-svm-gateway`. It builds Gateway, PrefundedAdapter and AuthorityRequirementPlanner from `GATEWAY_COMMIT` in