Optimize account copies and use RefCell to handle duplicate accounts in BPF programs (#7958)

sdk/src/entrypoint.rs

@@ -4,10 +4,15 @@
 
 extern crate alloc;
 
-use crate::{account_info::AccountInfo, pubkey::Pubkey};
+use crate::{
+    account_info::{AccountInfo, AccountInfoMut},
+    pubkey::Pubkey,
+};
 use alloc::vec::Vec;
 use core::mem::size_of;
 use core::slice::{from_raw_parts, from_raw_parts_mut};
+use std::cell::RefCell;
+use std::rc::Rc;
 
 /// User implemented program entrypoint
 ///
@@ -15,7 +20,7 @@ use core::slice::{from_raw_parts, from_raw_parts_mut};
 /// accounts: Accounts passed as part of the instruction
 /// data: Instruction data
 pub type ProcessInstruction =
-    fn(program_id: &Pubkey, accounts: &mut [AccountInfo], data: &[u8]) -> bool;
+    fn(program_id: &Pubkey, accounts: &mut [AccountInfo], data: &[u8]) -> u32;
 
 /// Programs indicate success with a return value of 0
 pub const SUCCESS: u32 = 0;
@@ -57,37 +62,45 @@ pub unsafe fn deserialize<'a>(input: *mut u8) -> (&'a Pubkey, Vec<AccountInfo<'a
 
     let mut accounts = Vec::with_capacity(num_accounts);
     for _ in 0..num_accounts {
-        let is_signer = {
+        let dup_info = *(input.add(offset) as *const u8) as usize;
+        offset += size_of::<u8>();
+        if dup_info == 0 {
+            let is_signer = {
+                #[allow(clippy::cast_ptr_alignment)]
+                let is_signer_val = *(input.add(offset) as *const u64);
+                (is_signer_val != 0)
+            };
+            offset += size_of::<u64>();
+
+            let key: &Pubkey = &*(input.add(offset) as *const Pubkey);
+            offset += size_of::<Pubkey>();
+
             #[allow(clippy::cast_ptr_alignment)]
-            let is_signer_val = *(input.add(offset) as *const u64);
-            (is_signer_val != 0)
-        };
-        offset += size_of::<u64>();
+            let lamports = &mut *(input.add(offset) as *mut u64);
+            offset += size_of::<u64>();
 
-        let key: &Pubkey = &*(input.add(offset) as *const Pubkey);
-        offset += size_of::<Pubkey>();
+            #[allow(clippy::cast_ptr_alignment)]
+            let data_length = *(input.add(offset) as *const u64) as usize;
+            offset += size_of::<u64>();
 
-        #[allow(clippy::cast_ptr_alignment)]
-        let lamports = &mut *(input.add(offset) as *mut u64);
-        offset += size_of::<u64>();
+            let data = { from_raw_parts_mut(input.add(offset), data_length) };
+            offset += data_length;
 
-        #[allow(clippy::cast_ptr_alignment)]
-        let data_length = *(input.add(offset) as *const u64) as usize;
-        offset += size_of::<u64>();
+            let owner: &Pubkey = &*(input.add(offset) as *const Pubkey);
+            offset += size_of::<Pubkey>();
 
-        let data = { from_raw_parts_mut(input.add(offset), data_length) };
-        offset += data_length;
+            let m = Rc::new(RefCell::new(AccountInfoMut { lamports, data }));
 
-        let owner: &Pubkey = &*(input.add(offset) as *const Pubkey);
-        offset += size_of::<Pubkey>();
-
-        accounts.push(AccountInfo {
-            key,
-            is_signer,
-            lamports,
-            data,
-            owner,
-        });
+            accounts.push(AccountInfo {
+                key,
+                is_signer,
+                m,
+                owner,
+            });
+        } else {
+            // Duplicate account, clone the original
+            accounts.push(accounts[dup_info].clone());
+        }
     }
 
     // Instruction data