Make instruction data opaque to runtime (#6470)

sdk/src/loader_instruction.rs

@@ -1,6 +1,8 @@
 use crate::instruction::{AccountMeta, Instruction};
 use crate::pubkey::Pubkey;
 use crate::sysvar::rent;
+use bincode::serialize;
+use serde::Serialize;
 
 #[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
 pub enum LoaderInstruction {
@@ -34,6 +36,7 @@ pub enum LoaderInstruction {
     },
 }
 
+/// Create an instruction to write program data into an account
 pub fn write(
     account_pubkey: &Pubkey,
     program_id: &Pubkey,
@@ -48,6 +51,7 @@ pub fn write(
     )
 }
 
+/// Create an instruction to finalize a program data account, once finalized it can no longer be modified
 pub fn finalize(account_pubkey: &Pubkey, program_id: &Pubkey) -> Instruction {
     let account_metas = vec![
         AccountMeta::new(*account_pubkey, true),
@@ -55,3 +59,15 @@ pub fn finalize(account_pubkey: &Pubkey, program_id: &Pubkey) -> Instruction {
     ];
     Instruction::new(*program_id, &LoaderInstruction::Finalize, account_metas)
 }
+
+// Create an instruction to Invoke a program's "main" entrypoint with the given data
+pub fn invoke_main<T: Serialize>(
+    program_id: &Pubkey,
+    data: &T,
+    account_metas: Vec<AccountMeta>,
+) -> Instruction {
+    let ix_data = LoaderInstruction::InvokeMain {
+        data: serialize(data).unwrap().to_vec(),
+    };
+    Instruction::new(*program_id, &ix_data, account_metas)
+}