Feature - JIT enable host stack frames (#31)

* Adds cfg feature "jit-enable-host-stack-frames".

* Adds stmt_expr_attribute_asm!().

Cargo.toml

@@ -39,6 +39,7 @@ libc = { version = "0.2", optional = true }
 [features]
 default = ["jit"]
 jit = ["libc", "winapi"]
+jit-enable-host-stack-frames = ["jit"]
 fuzzer-not-safe-for-production = ["arbitrary"]
 debugger = ["gdbstub"]
 shuttle-test = ["dep:shuttle"]

src/jit.rs

@@ -121,13 +121,30 @@ impl JitProgram {
         registers: [u64; 12],
     ) {
         unsafe {
-            std::arch::asm!(
+            let runtime_environment = std::ptr::addr_of_mut!(*vm)
+                .cast::<u64>()
+                .offset(get_runtime_environment_key() as isize);
+            let instruction_meter =
+                (vm.previous_instruction_meter as i64).wrapping_add(registers[11] as i64);
+            let entrypoint = &self.text_section
+                [self.pc_section[registers[11] as usize] as usize & (i32::MAX as u32 as usize)]
+                as *const u8;
+            macro_rules! stmt_expr_attribute_asm {
+                ($($prologue:literal,)+ cfg(not(feature = $feature:literal)), $guarded:tt, $($epilogue:tt)+) => {
+                    #[cfg(feature = $feature)]
+                    std::arch::asm!($($prologue,)+ $($epilogue)+);
+                    #[cfg(not(feature = $feature))]
+                    std::arch::asm!($($prologue,)+ $guarded, $($epilogue)+);
+                }
+            }
+            stmt_expr_attribute_asm!(
                 // RBP and RBX must be saved and restored manually in the current version of rustc and llvm.
                 "push rbx",
                 "push rbp",
                 "mov [{host_stack_pointer}], rsp",
                 "add QWORD PTR [{host_stack_pointer}], -8",
                 // RBP is zeroed out in order not to compromise the runtime environment (RDI) encryption.
+                cfg(not(feature = "jit-enable-host-stack-frames")),
                 "xor rbp, rbp",
                 "mov [rsp-8], rax",
                 "mov rax, [r11 + 0x00]",
@@ -146,9 +163,9 @@ impl JitProgram {
                 "pop rbp",
                 "pop rbx",
                 host_stack_pointer = in(reg) &mut vm.host_stack_pointer,
-                inlateout("rdi") std::ptr::addr_of_mut!(*vm).cast::<u64>().offset(get_runtime_environment_key() as isize) => _,
-                inlateout("r10") (vm.previous_instruction_meter as i64).wrapping_add(registers[11] as i64) => _,
-                inlateout("rax") &self.text_section[self.pc_section[registers[11] as usize] as usize & (i32::MAX as u32 as usize)] as *const u8 => _,
+                inlateout("rdi") runtime_environment => _,
+                inlateout("r10") instruction_meter => _,
+                inlateout("rax") entrypoint => _,
                 inlateout("r11") &registers => _,
                 lateout("rsi") _, lateout("rdx") _, lateout("rcx") _, lateout("r8") _,
                 lateout("r9") _, lateout("r12") _, lateout("r13") _, lateout("r14") _, lateout("r15") _,