provide full Rust panic messages in BPF and add memory optimizations (#13455)

programs/bpf/rust/panic/src/lib.rs

@@ -1,8 +1,24 @@
 //! @brief Example Rust-based BPF program that panics
 
-extern crate solana_program;
-
+#[cfg(all(feature = "custom-panic", target_arch = "bpf"))]
 #[no_mangle]
-pub extern "C" fn entrypoint(_input: *mut u8) -> u64 {
-    panic!();
+fn custom_panic(info: &core::panic::PanicInfo<'_>) {
+    // Note: Full panic reporting is included here for testing purposes
+    solana_program::info!("program custom panic enabled");
+    solana_program::info!(&format!("{}", info));
+}
+
+extern crate solana_program;
+use solana_program::{
+    account_info::AccountInfo, entrypoint, entrypoint::ProgramResult, pubkey::Pubkey,
+};
+
+entrypoint!(process_instruction);
+fn process_instruction(
+    _program_id: &Pubkey,
+    _accounts: &[AccountInfo],
+    _instruction_data: &[u8],
+) -> ProgramResult {
+    assert_eq!(1, 2);
+    Ok(())
 }