Perf: Store deserialized sysvars in the sysvars cache (backport #22455) (#22480)

* Perf: Store deserialized sysvars in the sysvars cache (#22455)

* Perf: Store deserialized sysvars in sysvars cache

* add bench

* resolve conflicts

Co-authored-by: Justin Starry <justin@solana.com>

program-runtime/src/sysvar_cache.rs

@@ -1,9 +1,13 @@
+#[allow(deprecated)]
+use solana_sdk::sysvar::fees::Fees;
 use {
     solana_sdk::{
-        account::{AccountSharedData, ReadableAccount},
-        pubkey::Pubkey,
+        instruction::InstructionError,
+        sysvar::{
+            clock::Clock, epoch_schedule::EpochSchedule, rent::Rent, slot_hashes::SlotHashes,
+        },
     },
-    std::ops::Deref,
+    std::sync::Arc,
 };
 
 #[cfg(RUSTC_WITH_SPECIALIZATION)]
@@ -15,25 +19,63 @@ impl ::solana_frozen_abi::abi_example::AbiExample for SysvarCache {
 }
 
 #[derive(Default, Clone, Debug)]
-pub struct SysvarCache(Vec<(Pubkey, Vec<u8>)>);
-
-impl Deref for SysvarCache {
-    type Target = Vec<(Pubkey, Vec<u8>)>;
-    fn deref(&self) -> &Self::Target {
-        &self.0
-    }
+pub struct SysvarCache {
+    clock: Option<Arc<Clock>>,
+    epoch_schedule: Option<Arc<EpochSchedule>>,
+    #[allow(deprecated)]
+    fees: Option<Arc<Fees>>,
+    rent: Option<Arc<Rent>>,
+    slot_hashes: Option<Arc<SlotHashes>>,
 }
 
 impl SysvarCache {
-    pub fn push_entry(&mut self, pubkey: Pubkey, data: Vec<u8>) {
-        self.0.push((pubkey, data));
+    pub fn get_clock(&self) -> Result<Arc<Clock>, InstructionError> {
+        self.clock
+            .clone()
+            .ok_or(InstructionError::UnsupportedSysvar)
     }
 
-    pub fn update_entry(&mut self, pubkey: &Pubkey, new_account: &AccountSharedData) {
-        if let Some(position) = self.iter().position(|(id, _data)| id == pubkey) {
-            self.0[position].1 = new_account.data().to_vec();
-        } else {
-            self.0.push((*pubkey, new_account.data().to_vec()));
-        }
+    pub fn set_clock(&mut self, clock: Clock) {
+        self.clock = Some(Arc::new(clock));
+    }
+
+    pub fn get_epoch_schedule(&self) -> Result<Arc<EpochSchedule>, InstructionError> {
+        self.epoch_schedule
+            .clone()
+            .ok_or(InstructionError::UnsupportedSysvar)
+    }
+
+    pub fn set_epoch_schedule(&mut self, epoch_schedule: EpochSchedule) {
+        self.epoch_schedule = Some(Arc::new(epoch_schedule));
+    }
+
+    #[deprecated]
+    #[allow(deprecated)]
+    pub fn get_fees(&self) -> Result<Arc<Fees>, InstructionError> {
+        self.fees.clone().ok_or(InstructionError::UnsupportedSysvar)
+    }
+
+    #[deprecated]
+    #[allow(deprecated)]
+    pub fn set_fees(&mut self, fees: Fees) {
+        self.fees = Some(Arc::new(fees));
+    }
+
+    pub fn get_rent(&self) -> Result<Arc<Rent>, InstructionError> {
+        self.rent.clone().ok_or(InstructionError::UnsupportedSysvar)
+    }
+
+    pub fn set_rent(&mut self, rent: Rent) {
+        self.rent = Some(Arc::new(rent));
+    }
+
+    pub fn get_slot_hashes(&self) -> Result<Arc<SlotHashes>, InstructionError> {
+        self.slot_hashes
+            .clone()
+            .ok_or(InstructionError::UnsupportedSysvar)
+    }
+
+    pub fn set_slot_hashes(&mut self, slot_hashes: SlotHashes) {
+        self.slot_hashes = Some(Arc::new(slot_hashes));
     }
 }