Struct JitContext 

#[repr(C)]
pub struct JitContext {

    pub regs: [u64; 15],
    pub gas: i64,
    pub exit_reason: u32,
    pub exit_arg: u32,
    pub heap_base: u32,
    pub heap_top: u32,
    pub entry_pc: u32,
    pub pc: u32,
    pub dispatch_table: *const i32,
    pub code_base: u64,
    pub flat_buf: *mut u8,
    pub fast_reentry: u32,
    pub _pad2: u32,
    pub max_heap_pages: u32,
    pub _pad3: u32,
    pub host_rsp_base: u64,
}

JIT execution context passed to compiled code via R15. Must be #[repr(C)] with exact field ordering matching the CTX_* offset constants in codegen.

Fields

regs: [u64; 15]

PVM2 registers (offset 0, 15 × 8 = 120 bytes). Slots 0..12 are the host-mapped GPRs (flushed to/from x86 registers at the prologue / epilogue); slots 13/14 are the spilled x3/x4, which live here in memory for the whole block and are materialised per access.

gas: i64

Gas counter. Signed to detect underflow.

exit_reason: u32

Exit reason code.

exit_arg: u32

Exit argument — host call ID, page fault addr, etc.

heap_base: u32

Heap base address.

heap_top: u32

Current heap top.

entry_pc: u32

Entry PC for re-entry after host calls.

pc: u32

Current PC when execution stopped (offset 164).

dispatch_table: *const i32

Dispatch table: PVM PC → native code offset (offset 168).

code_base: u64

Base address of native code (offset 176).

flat_buf: *mut u8

Flat guest memory buffer base pointer (offset 184).

fast_reentry: u32

Fast re-entry flag.

_pad2: u32

max_heap_pages: u32

Maximum heap pages — grow_heap refuses beyond this.

_pad3: u32

host_rsp_base: u64

RSP saved at JIT entry (after the prologue’s callee-saved pushes but before any guest code runs). The exit_label restores RSP from this slot before popping the callee-saved registers, so an OOG / page-fault redirect taken mid-sequence leaves the exit path with a clean stack.