Panic asm exit, unsafe_no_disc accounts, PDA bump auto-detection

[L0STE]

Three independent improvements to the derive macros and runtime, plus a GitHub issue for future work.

Changes

1. Panic infrastructure → inline asm exit

Before: Panic handler calls sol_log_("PANIC", 5) then enters loop {}, burning all remaining CU before the SVM kills the program. The no_alloc! allocator triggers the same path via panic!(""), pulling in format machinery.

After: New abort_program() function in quasar-lang emits two SBF instructions: lddw r0, 0x100000000; exit. Immediately terminates with ProgramError::Custom(0). No string in .rodata, no syscall, no loop. The off-chain path still panics with a descriptive message for test ergonomics.

Three call sites updated:

• #[program]-emitted panic handler (derive/src/program.rs)
• no_alloc! allocator (lang/src/entrypoint.rs)
• standalone panic_handler! macro (lang/src/entrypoint.rs)

Required #![feature(asm_experimental_arch)] on the quasar-lang crate (SBF target only). The asm lives in quasar-lang so user crates don't need the feature gate.

Vault binary: 6,928 → 6,888 bytes (−40 bytes)

2. #[account(unsafe_no_disc)]

Opt-in attribute for accounts that don't need a discriminator — replicates the SPL Token AccountCheck pattern (size-only validation, no disc offset in Deref).

#[account(unsafe_no_disc)] generates:

• Discriminator::DISCRIMINATOR = &[]
• Space::SPACE = sizeof(ZcType) (no disc bytes added)
• AccountCheck::check — size-only, no disc byte validation
• Deref at data_ptr().add(0) — no offset

The unsafe_ prefix is the safety contract: the developer must ensure account type uniqueness via size. Rejected for dynamic fields (String/Vec/tail). Init and close paths work unchanged — copy_nonoverlapping with length 0 is a no-op, and close zeroes the first 8 bytes of actual data as defense-in-depth.

3. PDA bump auto-detection

When bump is bare (no = expr), we now auto-detect the bump from two sources before falling back to based_try_find_program_address (~544 CU):

Source 1 — Instruction args: If the Accounts struct has #[instruction(vault_bump: u8)] and a PDA field named vault with bare bump, the vault_bump arg auto-binds to verify_program_address (~200 CU). Also matches a bare bump: u8 arg when there's exactly one bare-bump PDA in the struct.

Source 2 — Stored bump in account data: If the inner type of Account<T> has a bump: u8 field, the #[account] macro sets Discriminator::BUMP_OFFSET = Some(disc_len + offset_of!(ZcType, bump)). At PDA check time, for non-init fields, the generated code reads the bump from the raw account data at that offset and uses verify_program_address. The if let Some(offset) = BUMP_OFFSET branch is constant-folded by LLVM via LTO — types without a stored bump compile down to the find path with zero overhead.

Priority: instruction arg > stored bump > find.

[github-actions]

⚡ CU Benchmark (Vault)

Instruction	Base	PR	Delta
Deposit	1,577	1,577	0 ⚪
Withdraw	411	411	0 ⚪

Binary size: 6,888 bytes (-40 🟢 bytes)