loader-v3: Add UpgradeableLoaderInstruction::Migrate (#9)

* loader-v3: Add `UpgradeableLoaderInstruction::Migrate`

#### Problem

The SDK changes from anza-xyz/agave#4661 need to
be applied here.

See [SIMD-0167](solana-foundation/solana-improvement-documents#167).

#### Summary of Changes

Feature Gate Issue: anza-xyz/feature-gate-tracker#78

* Avoid change in solana-program

---------

Co-authored-by: Alexander Meißner <[email protected]>

loader-v3-interface/src/instruction.rs

@@ -5,7 +5,7 @@ use {
     crate::{get_program_data_address, state::UpgradeableLoaderState},
     solana_instruction::{error::InstructionError, AccountMeta, Instruction},
     solana_pubkey::Pubkey,
-    solana_sdk_ids::{bpf_loader_upgradeable::id, sysvar},
+    solana_sdk_ids::{bpf_loader_upgradeable::id, loader_v4, sysvar},
     solana_system_interface::instruction as system_instruction,
 };
 
@@ -171,6 +171,14 @@ pub enum UpgradeableLoaderInstruction {
     ///   1. `[signer]` The current authority.
     ///   2. `[signer]` The new authority.
     SetAuthorityChecked,
+
+    /// Migrate the program to loader-v4.
+    ///
+    /// # Account references
+    ///   0. `[writable]` The ProgramData account.
+    ///   1. `[writable]` The Program account.
+    ///   2. `[signer]` The current authority.
+    Migrate,
 }
 
 #[cfg(feature = "bincode")]
@@ -299,6 +307,10 @@ pub fn is_set_authority_checked_instruction(instruction_data: &[u8]) -> bool {
     !instruction_data.is_empty() && 7 == instruction_data[0]
 }
 
+pub fn is_migrate_instruction(instruction_data: &[u8]) -> bool {
+    !instruction_data.is_empty() && 8 == instruction_data[0]
+}
+
 #[cfg(feature = "bincode")]
 /// Returns the instructions required to set a buffers's authority.
 pub fn set_buffer_authority(
@@ -440,6 +452,23 @@ pub fn extend_program(
     )
 }
 
+/// Returns the instructions required to migrate a program to loader-v4.
+#[cfg(feature = "bincode")]
+pub fn migrate_program(
+    programdata_address: &Pubkey,
+    program_address: &Pubkey,
+    authority: &Pubkey,
+) -> Instruction {
+    let accounts = vec![
+        AccountMeta::new(*programdata_address, false),
+        AccountMeta::new(*program_address, false),
+        AccountMeta::new_readonly(*authority, true),
+        AccountMeta::new_readonly(loader_v4::id(), false),
+    ];
+
+    Instruction::new_with_bincode(id(), &UpgradeableLoaderInstruction::Migrate, accounts)
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -533,4 +562,13 @@ mod tests {
             UpgradeableLoaderInstruction::Upgrade {},
         );
     }
+
+    #[test]
+    fn test_is_migrate_instruction() {
+        assert!(!is_migrate_instruction(&[]));
+        assert_is_instruction(
+            is_migrate_instruction,
+            UpgradeableLoaderInstruction::Migrate {},
+        );
+    }
 }