Rent tangential stuff (#5910)

* rename rent.rs to rent_calculator.rs

* add rent sysvar

* integrate rent_calculator with bank

* rent_calculator integration with genesis

* add test for rent sysvar

runtime/src/bank.rs

@@ -41,7 +41,7 @@ use solana_sdk::{
     signature::{Keypair, Signature},
     system_transaction,
     sysvar::{
-        clock, fees, rewards,
+        clock, fees, rent, rewards,
         slot_hashes::{self, SlotHashes},
         stake_history,
     },
@@ -354,6 +354,7 @@ impl Bank {
         new.update_stake_history(Some(parent.epoch()));
         new.update_clock();
         new.update_fees();
+        new.update_rent();
         new
     }
 
@@ -426,6 +427,13 @@ impl Bank {
         self.store_account(&fees::id(), &fees::create_account(1, &self.fee_calculator));
     }
 
+    fn update_rent(&self) {
+        self.store_account(
+            &rent::id(),
+            &rent::create_account(1, &self.rent_collector.rent_calculator),
+        );
+    }
+
     fn update_stake_history(&self, epoch: Option<Epoch>) {
         if epoch == Some(self.epoch()) {
             return;
@@ -620,6 +628,14 @@ impl Bank {
 
         self.inflation = genesis_block.inflation;
 
+        let rent_calculator = genesis_block.rent_calculator;
+        self.rent_collector = RentCollector::new(
+            self.epoch,
+            &self.epoch_schedule,
+            self.slots_per_year,
+            &rent_calculator,
+        );
+
         // Add additional native programs specified in the genesis block
         for (name, program_id) in &genesis_block.native_instruction_processors {
             self.register_native_instruction_processor(name, program_id);

runtime/src/rent_collector.rs

@@ -1,13 +1,13 @@
 //! calculate and collect rent from Accounts
 use crate::epoch_schedule::EpochSchedule;
-use solana_sdk::{account::Account, clock::Epoch, rent::Rent};
+use solana_sdk::{account::Account, clock::Epoch, rent_calculator::RentCalculator};
 
 #[derive(Default, Serialize, Deserialize, Clone)]
 pub struct RentCollector {
     pub epoch: Epoch,
     pub epoch_schedule: EpochSchedule,
     pub slots_per_year: f64,
-    pub rent: Rent,
+    pub rent_calculator: RentCalculator,
 }
 
 impl RentCollector {
@@ -15,13 +15,13 @@ impl RentCollector {
         epoch: Epoch,
         epoch_schedule: &EpochSchedule,
         slots_per_year: f64,
-        rent: &Rent,
+        rent_calculator: &RentCalculator,
     ) -> Self {
         Self {
             epoch,
             epoch_schedule: *epoch_schedule,
             slots_per_year,
-            rent: *rent,
+            rent_calculator: *rent_calculator,
         }
     }
 
@@ -42,7 +42,7 @@ impl RentCollector {
                 .map(|epoch| self.epoch_schedule.get_slots_in_epoch(epoch + 1))
                 .sum();
 
-            let (rent_due, exempt) = self.rent.due(
+            let (rent_due, exempt) = self.rent_calculator.due(
                 account.lamports,
                 account.data.len(),
                 slots_elapsed as f64 / self.slots_per_year,