wasmer/lib/runtime-core/src/state.rs
2019-06-27 15:49:43 +08:00

847 lines
29 KiB
Rust

use std::collections::BTreeMap;
use std::ops::Bound::{Included, Unbounded};
#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
pub struct RegisterIndex(pub usize);
#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
pub enum WasmAbstractValue {
Runtime,
Const(u64),
}
#[derive(Clone, Debug)]
pub struct MachineState {
pub stack_values: Vec<MachineValue>,
pub register_values: Vec<MachineValue>,
pub wasm_stack: Vec<WasmAbstractValue>,
pub wasm_stack_private_depth: usize,
pub wasm_inst_offset: usize,
}
#[derive(Clone, Debug, Default)]
pub struct MachineStateDiff {
pub last: Option<usize>,
pub stack_push: Vec<MachineValue>,
pub stack_pop: usize,
pub reg_diff: Vec<(RegisterIndex, MachineValue)>,
pub wasm_stack_push: Vec<WasmAbstractValue>,
pub wasm_stack_pop: usize,
pub wasm_stack_private_depth: usize, // absolute value; not a diff.
pub wasm_inst_offset: usize, // absolute value; not a diff.
}
#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
pub enum MachineValue {
Undefined,
Vmctx,
PreserveRegister(RegisterIndex),
CopyStackBPRelative(i32), // relative to Base Pointer, in byte offset
ExplicitShadow, // indicates that all values above this are above the shadow region
WasmStack(usize),
WasmLocal(usize),
}
#[derive(Clone, Debug)]
pub struct FunctionStateMap {
pub initial: MachineState,
pub local_function_id: usize,
pub locals: Vec<WasmAbstractValue>,
pub shadow_size: usize, // for single-pass backend, 32 bytes on x86-64
pub diffs: Vec<MachineStateDiff>,
pub wasm_function_header_target_offset: Option<usize>,
pub wasm_offset_to_target_offset: Vec<usize>,
pub loop_offsets: BTreeMap<usize, OffsetInfo>, /* suspend_offset -> info */
pub call_offsets: BTreeMap<usize, OffsetInfo>, /* suspend_offset -> info */
pub trappable_offsets: BTreeMap<usize, OffsetInfo>, /* suspend_offset -> info */
}
#[derive(Clone, Debug)]
pub struct OffsetInfo {
pub diff_id: usize,
pub activate_offset: usize,
}
#[derive(Clone, Debug)]
pub struct ModuleStateMap {
pub local_functions: BTreeMap<usize, FunctionStateMap>,
pub total_size: usize,
}
#[derive(Clone, Debug, Serialize, Deserialize)]
pub struct WasmFunctionStateDump {
pub local_function_id: usize,
pub wasm_inst_offset: usize,
pub stack: Vec<Option<u64>>,
pub locals: Vec<Option<u64>>,
}
#[derive(Clone, Debug, Serialize, Deserialize)]
pub struct ExecutionStateImage {
pub frames: Vec<WasmFunctionStateDump>,
}
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct InstanceImage {
pub memory: Option<Vec<u8>>,
pub globals: Vec<u64>,
pub execution_state: ExecutionStateImage,
}
impl ModuleStateMap {
fn lookup_call_ip(&self, ip: usize, base: usize) -> Option<(&FunctionStateMap, MachineState)> {
if ip < base || ip - base >= self.total_size {
None
} else {
//println!("lookup ip: {} in {:?}", ip - base, self.local_functions);
let (_, fsm) = self
.local_functions
.range((Unbounded, Included(&(ip - base))))
.last()
.unwrap();
match fsm.call_offsets.get(&(ip - base)) {
Some(x) => Some((fsm, fsm.diffs[x.diff_id].build_state(fsm))),
None => None,
}
}
}
fn lookup_trappable_ip(
&self,
ip: usize,
base: usize,
) -> Option<(&FunctionStateMap, MachineState)> {
if ip < base || ip - base >= self.total_size {
None
} else {
//println!("lookup ip: {} in {:?}", ip - base, self.local_functions);
let (_, fsm) = self
.local_functions
.range((Unbounded, Included(&(ip - base))))
.last()
.unwrap();
match fsm.trappable_offsets.get(&(ip - base)) {
Some(x) => Some((fsm, fsm.diffs[x.diff_id].build_state(fsm))),
None => None,
}
}
}
fn lookup_loop_ip(&self, ip: usize, base: usize) -> Option<(&FunctionStateMap, MachineState)> {
if ip < base || ip - base >= self.total_size {
None
} else {
//println!("lookup ip: {} in {:?}", ip - base, self.local_functions);
let (_, fsm) = self
.local_functions
.range((Unbounded, Included(&(ip - base))))
.last()
.unwrap();
match fsm.loop_offsets.get(&(ip - base)) {
Some(x) => Some((fsm, fsm.diffs[x.diff_id].build_state(fsm))),
None => None,
}
}
}
}
impl FunctionStateMap {
pub fn new(
initial: MachineState,
local_function_id: usize,
shadow_size: usize,
locals: Vec<WasmAbstractValue>,
) -> FunctionStateMap {
FunctionStateMap {
initial,
local_function_id,
shadow_size,
locals,
diffs: vec![],
wasm_function_header_target_offset: None,
wasm_offset_to_target_offset: Vec::new(),
loop_offsets: BTreeMap::new(),
call_offsets: BTreeMap::new(),
trappable_offsets: BTreeMap::new(),
}
}
}
impl MachineState {
pub fn diff(&self, old: &MachineState) -> MachineStateDiff {
let first_diff_stack_depth: usize = self
.stack_values
.iter()
.zip(old.stack_values.iter())
.enumerate()
.find(|&(_, (&a, &b))| a != b)
.map(|x| x.0)
.unwrap_or(old.stack_values.len().min(self.stack_values.len()));
assert_eq!(self.register_values.len(), old.register_values.len());
let reg_diff: Vec<_> = self
.register_values
.iter()
.zip(old.register_values.iter())
.enumerate()
.filter(|&(_, (&a, &b))| a != b)
.map(|(i, (&a, _))| (RegisterIndex(i), a))
.collect();
let first_diff_wasm_stack_depth: usize = self
.wasm_stack
.iter()
.zip(old.wasm_stack.iter())
.enumerate()
.find(|&(_, (&a, &b))| a != b)
.map(|x| x.0)
.unwrap_or(old.wasm_stack.len().min(self.wasm_stack.len()));
MachineStateDiff {
last: None,
stack_push: self.stack_values[first_diff_stack_depth..].to_vec(),
stack_pop: old.stack_values.len() - first_diff_stack_depth,
reg_diff: reg_diff,
wasm_stack_push: self.wasm_stack[first_diff_wasm_stack_depth..].to_vec(),
wasm_stack_pop: old.wasm_stack.len() - first_diff_wasm_stack_depth,
wasm_stack_private_depth: self.wasm_stack_private_depth,
wasm_inst_offset: self.wasm_inst_offset,
}
}
}
impl MachineStateDiff {
pub fn build_state(&self, m: &FunctionStateMap) -> MachineState {
let mut chain: Vec<&MachineStateDiff> = vec![];
chain.push(self);
let mut current = self.last;
while let Some(x) = current {
let that = &m.diffs[x];
current = that.last;
chain.push(that);
}
chain.reverse();
let mut state = m.initial.clone();
for x in chain {
for _ in 0..x.stack_pop {
state.stack_values.pop().unwrap();
}
for v in &x.stack_push {
state.stack_values.push(*v);
}
for &(index, v) in &x.reg_diff {
state.register_values[index.0] = v;
}
for _ in 0..x.wasm_stack_pop {
state.wasm_stack.pop().unwrap();
}
for v in &x.wasm_stack_push {
state.wasm_stack.push(*v);
}
}
state.wasm_stack_private_depth = self.wasm_stack_private_depth;
state.wasm_inst_offset = self.wasm_inst_offset;
state
}
}
impl ExecutionStateImage {
pub fn print_backtrace_if_needed(&self) {
use std::env;
if let Ok(x) = env::var("WASMER_BACKTRACE") {
if x == "1" {
eprintln!("{}", self.colored_output());
return;
}
}
eprintln!("Run with `WASMER_BACKTRACE=1` environment variable to display a backtrace.");
}
pub fn colored_output(&self) -> String {
use colored::*;
fn join_strings(x: impl Iterator<Item = String>, sep: &str) -> String {
let mut ret = String::new();
let mut first = true;
for s in x {
if first {
first = false;
} else {
ret += sep;
}
ret += &s;
}
ret
}
fn format_optional_u64_sequence(x: &[Option<u64>]) -> String {
if x.len() == 0 {
"(empty)".into()
} else {
join_strings(
x.iter().enumerate().map(|(i, x)| {
format!(
"[{}] = {}",
i,
x.map(|x| format!("{}", x))
.unwrap_or_else(|| "?".to_string())
.bold()
.cyan()
)
}),
", ",
)
}
}
let mut ret = String::new();
if self.frames.len() == 0 {
ret += &"Unknown fault address, cannot read stack.".yellow();
ret += "\n";
} else {
ret += &"Backtrace:".bold();
ret += "\n";
for (i, f) in self.frames.iter().enumerate() {
ret += &format!("* Frame {} @ Local function {}", i, f.local_function_id).bold();
ret += "\n";
ret += &format!(
" {} {}\n",
"Offset:".bold().yellow(),
format!("{}", f.wasm_inst_offset).bold().cyan(),
);
ret += &format!(
" {} {}\n",
"Locals:".bold().yellow(),
format_optional_u64_sequence(&f.locals)
);
ret += &format!(
" {} {}\n\n",
"Stack:".bold().yellow(),
format_optional_u64_sequence(&f.stack)
);
}
}
ret
}
}
impl InstanceImage {
pub fn from_bytes(input: &[u8]) -> Option<InstanceImage> {
use bincode::deserialize;
match deserialize(input) {
Ok(x) => Some(x),
Err(_) => None,
}
}
pub fn to_bytes(&self) -> Vec<u8> {
use bincode::serialize;
serialize(self).unwrap()
}
}
#[cfg(all(unix, target_arch = "x86_64"))]
pub mod x64 {
use super::*;
use crate::alternative_stack::{catch_unsafe_unwind, run_on_alternative_stack};
use crate::codegen::BkptMap;
use crate::structures::TypedIndex;
use crate::types::LocalGlobalIndex;
use crate::vm::Ctx;
use std::any::Any;
use std::ops::Bound::Excluded;
pub fn new_machine_state() -> MachineState {
MachineState {
stack_values: vec![],
register_values: vec![MachineValue::Undefined; 16 + 8],
wasm_stack: vec![],
wasm_stack_private_depth: 0,
wasm_inst_offset: ::std::usize::MAX,
}
}
#[warn(unused_variables)]
pub unsafe fn invoke_call_return_on_stack(
msm: &ModuleStateMap,
code_base: usize,
image: InstanceImage,
vmctx: &mut Ctx,
breakpoints: Option<BkptMap>,
) -> Result<u64, Box<dyn Any>> {
let mut stack: Vec<u64> = vec![0; 1048576 * 8 / 8]; // 8MB stack
let mut stack_offset: usize = stack.len();
stack_offset -= 3; // placeholder for call return
let mut last_stack_offset: u64 = 0; // rbp
let mut known_registers: [Option<u64>; 24] = [None; 24];
let local_functions_vec: Vec<&FunctionStateMap> =
msm.local_functions.iter().map(|(_, v)| v).collect();
// Bottom to top
for f in image.execution_state.frames.iter().rev() {
let fsm = local_functions_vec[f.local_function_id];
let begin_offset = if f.wasm_inst_offset == ::std::usize::MAX {
fsm.wasm_function_header_target_offset.unwrap()
} else {
fsm.wasm_offset_to_target_offset[f.wasm_inst_offset]
};
let (target_inst_offset, diff_id) = fsm
.loop_offsets
.get(&begin_offset)
.map(|v| (v.activate_offset, v.diff_id))
.or_else(|| {
fsm.trappable_offsets
.get(&begin_offset)
.map(|v| (v.activate_offset, v.diff_id))
})
.or_else(|| {
// Left bound must be Excluded because it's possible that the previous instruction's (after-)call offset == call_begin_offset.
// This might not be the correct offset if begin_offset itself does not correspond to a call(_indirect) instruction,
// but anyway safety isn't broken because diff_id always corresponds to target_inst_offset.
fsm.call_offsets
.range((Excluded(&begin_offset), Unbounded))
.next()
.map(|(_, v)| (v.activate_offset, v.diff_id))
})
.expect("instruction offset not found in any offset type");
let diff = &fsm.diffs[diff_id];
let state = diff.build_state(fsm);
stack_offset -= 1;
stack[stack_offset] = stack.as_ptr().offset(last_stack_offset as isize) as usize as u64; // push rbp
last_stack_offset = stack_offset as _;
let mut got_explicit_shadow = false;
for v in state.stack_values.iter() {
match *v {
MachineValue::Undefined => stack_offset -= 1,
MachineValue::Vmctx => {
stack_offset -= 1;
stack[stack_offset] = vmctx as *mut Ctx as usize as u64;
}
MachineValue::PreserveRegister(index) => {
stack_offset -= 1;
stack[stack_offset] = known_registers[index.0].unwrap_or(0);
}
MachineValue::CopyStackBPRelative(byte_offset) => {
assert!(byte_offset % 8 == 0);
let target_offset = (byte_offset / 8) as isize;
let v = stack[(last_stack_offset as isize + target_offset) as usize];
stack_offset -= 1;
stack[stack_offset] = v;
}
MachineValue::ExplicitShadow => {
assert!(fsm.shadow_size % 8 == 0);
stack_offset -= fsm.shadow_size / 8;
got_explicit_shadow = true;
}
MachineValue::WasmStack(x) => {
stack_offset -= 1;
match state.wasm_stack[x] {
WasmAbstractValue::Const(x) => {
stack[stack_offset] = x;
}
WasmAbstractValue::Runtime => {
stack[stack_offset] = f.stack[x].unwrap();
}
}
}
MachineValue::WasmLocal(x) => {
stack_offset -= 1;
match fsm.locals[x] {
WasmAbstractValue::Const(x) => {
stack[stack_offset] = x;
}
WasmAbstractValue::Runtime => {
stack[stack_offset] = f.locals[x].unwrap();
}
}
}
}
}
if !got_explicit_shadow {
assert!(fsm.shadow_size % 8 == 0);
stack_offset -= fsm.shadow_size / 8;
}
for (i, v) in state.register_values.iter().enumerate() {
match *v {
MachineValue::Undefined => {}
MachineValue::Vmctx => {
known_registers[i] = Some(vmctx as *mut Ctx as usize as u64);
}
MachineValue::WasmStack(x) => match state.wasm_stack[x] {
WasmAbstractValue::Const(x) => {
known_registers[i] = Some(x);
}
WasmAbstractValue::Runtime => {
known_registers[i] = Some(f.stack[x].unwrap());
}
},
MachineValue::WasmLocal(x) => match fsm.locals[x] {
WasmAbstractValue::Const(x) => {
known_registers[i] = Some(x);
}
WasmAbstractValue::Runtime => {
known_registers[i] = Some(f.locals[x].unwrap());
}
},
_ => unreachable!(),
}
}
// no need to check 16-byte alignment here because it's possible that we're not at a call entry.
stack_offset -= 1;
stack[stack_offset] = (code_base + target_inst_offset) as u64; // return address
}
stack_offset -= 1;
stack[stack_offset] = known_registers[X64Register::GPR(GPR::R15).to_index().0].unwrap_or(0);
stack_offset -= 1;
stack[stack_offset] = known_registers[X64Register::GPR(GPR::R14).to_index().0].unwrap_or(0);
stack_offset -= 1;
stack[stack_offset] = known_registers[X64Register::GPR(GPR::R13).to_index().0].unwrap_or(0);
stack_offset -= 1;
stack[stack_offset] = known_registers[X64Register::GPR(GPR::R12).to_index().0].unwrap_or(0);
stack_offset -= 1;
stack[stack_offset] = known_registers[X64Register::GPR(GPR::R11).to_index().0].unwrap_or(0);
stack_offset -= 1;
stack[stack_offset] = known_registers[X64Register::GPR(GPR::R10).to_index().0].unwrap_or(0);
stack_offset -= 1;
stack[stack_offset] = known_registers[X64Register::GPR(GPR::R9).to_index().0].unwrap_or(0);
stack_offset -= 1;
stack[stack_offset] = known_registers[X64Register::GPR(GPR::R8).to_index().0].unwrap_or(0);
stack_offset -= 1;
stack[stack_offset] = known_registers[X64Register::GPR(GPR::RSI).to_index().0].unwrap_or(0);
stack_offset -= 1;
stack[stack_offset] = known_registers[X64Register::GPR(GPR::RDI).to_index().0].unwrap_or(0);
stack_offset -= 1;
stack[stack_offset] = known_registers[X64Register::GPR(GPR::RDX).to_index().0].unwrap_or(0);
stack_offset -= 1;
stack[stack_offset] = known_registers[X64Register::GPR(GPR::RCX).to_index().0].unwrap_or(0);
stack_offset -= 1;
stack[stack_offset] = known_registers[X64Register::GPR(GPR::RBX).to_index().0].unwrap_or(0);
stack_offset -= 1;
stack[stack_offset] = known_registers[X64Register::GPR(GPR::RAX).to_index().0].unwrap_or(0);
stack_offset -= 1;
stack[stack_offset] = stack.as_ptr().offset(last_stack_offset as isize) as usize as u64; // rbp
stack_offset -= 1;
stack[stack_offset] =
known_registers[X64Register::XMM(XMM::XMM7).to_index().0].unwrap_or(0);
stack_offset -= 1;
stack[stack_offset] =
known_registers[X64Register::XMM(XMM::XMM6).to_index().0].unwrap_or(0);
stack_offset -= 1;
stack[stack_offset] =
known_registers[X64Register::XMM(XMM::XMM5).to_index().0].unwrap_or(0);
stack_offset -= 1;
stack[stack_offset] =
known_registers[X64Register::XMM(XMM::XMM4).to_index().0].unwrap_or(0);
stack_offset -= 1;
stack[stack_offset] =
known_registers[X64Register::XMM(XMM::XMM3).to_index().0].unwrap_or(0);
stack_offset -= 1;
stack[stack_offset] =
known_registers[X64Register::XMM(XMM::XMM2).to_index().0].unwrap_or(0);
stack_offset -= 1;
stack[stack_offset] =
known_registers[X64Register::XMM(XMM::XMM1).to_index().0].unwrap_or(0);
stack_offset -= 1;
stack[stack_offset] =
known_registers[X64Register::XMM(XMM::XMM0).to_index().0].unwrap_or(0);
if let Some(ref memory) = image.memory {
assert!(vmctx.internal.memory_bound <= memory.len());
if vmctx.internal.memory_bound < memory.len() {
let grow: unsafe extern "C" fn(ctx: &mut Ctx, memory_index: usize, delta: usize) =
::std::mem::transmute((*vmctx.internal.intrinsics).memory_grow);
grow(
vmctx,
0,
(memory.len() - vmctx.internal.memory_bound) / 65536,
);
assert_eq!(vmctx.internal.memory_bound, memory.len());
}
::std::slice::from_raw_parts_mut(
vmctx.internal.memory_base,
vmctx.internal.memory_bound,
)
.copy_from_slice(memory);
}
let globals_len = (*vmctx.module).info.globals.len();
for i in 0..globals_len {
(*(*vmctx.local_backing).globals[LocalGlobalIndex::new(i)].vm_local_global()).data =
image.globals[i];
}
drop(image); // free up host memory
catch_unsafe_unwind(
|| {
run_on_alternative_stack(
stack.as_mut_ptr().offset(stack.len() as isize),
stack.as_mut_ptr().offset(stack_offset as isize),
)
},
breakpoints,
)
}
pub fn build_instance_image(
vmctx: &mut Ctx,
execution_state: ExecutionStateImage,
) -> InstanceImage {
unsafe {
let memory = if vmctx.internal.memory_base.is_null() {
None
} else {
Some(
::std::slice::from_raw_parts(
vmctx.internal.memory_base,
vmctx.internal.memory_bound,
)
.to_vec(),
)
};
// FIXME: Imported globals
let globals_len = (*vmctx.module).info.globals.len();
let globals: Vec<u64> = (0..globals_len)
.map(|i| {
(*vmctx.local_backing).globals[LocalGlobalIndex::new(i)]
.get()
.to_u64()
})
.collect();
InstanceImage {
memory: memory,
globals: globals,
execution_state: execution_state,
}
}
}
#[warn(unused_variables)]
pub unsafe fn read_stack(
msm: &ModuleStateMap,
code_base: usize,
mut stack: *const u64,
initially_known_registers: [Option<u64>; 24],
mut initial_address: Option<u64>,
) -> ExecutionStateImage {
let mut known_registers: [Option<u64>; 24] = initially_known_registers;
let mut results: Vec<WasmFunctionStateDump> = vec![];
for _ in 0.. {
let ret_addr = initial_address.take().unwrap_or_else(|| {
let x = *stack;
stack = stack.offset(1);
x
});
let (fsm, state) = match msm
.lookup_call_ip(ret_addr as usize, code_base)
.or_else(|| msm.lookup_trappable_ip(ret_addr as usize, code_base))
.or_else(|| msm.lookup_loop_ip(ret_addr as usize, code_base))
{
Some(x) => x,
_ => return ExecutionStateImage { frames: results },
};
let mut wasm_stack: Vec<Option<u64>> = state
.wasm_stack
.iter()
.map(|x| match *x {
WasmAbstractValue::Const(x) => Some(x),
WasmAbstractValue::Runtime => None,
})
.collect();
let mut wasm_locals: Vec<Option<u64>> = fsm
.locals
.iter()
.map(|x| match *x {
WasmAbstractValue::Const(x) => Some(x),
WasmAbstractValue::Runtime => None,
})
.collect();
// This must be before the next loop because that modifies `known_registers`.
for (i, v) in state.register_values.iter().enumerate() {
match *v {
MachineValue::Undefined => {}
MachineValue::Vmctx => {}
MachineValue::WasmStack(idx) => {
if let Some(v) = known_registers[i] {
wasm_stack[idx] = Some(v);
} else {
eprintln!(
"BUG: Register {} for WebAssembly stack slot {} has unknown value.",
i, idx
);
}
}
MachineValue::WasmLocal(idx) => {
if let Some(v) = known_registers[i] {
wasm_locals[idx] = Some(v);
}
}
_ => unreachable!(),
}
}
let mut found_shadow = false;
for v in state.stack_values.iter() {
match *v {
MachineValue::ExplicitShadow => {
found_shadow = true;
break;
}
_ => {}
}
}
if !found_shadow {
stack = stack.offset((fsm.shadow_size / 8) as isize);
}
for v in state.stack_values.iter().rev() {
match *v {
MachineValue::ExplicitShadow => {
stack = stack.offset((fsm.shadow_size / 8) as isize);
}
MachineValue::Undefined => {
stack = stack.offset(1);
}
MachineValue::Vmctx => {
stack = stack.offset(1);
}
MachineValue::PreserveRegister(idx) => {
known_registers[idx.0] = Some(*stack);
stack = stack.offset(1);
}
MachineValue::CopyStackBPRelative(_) => {
stack = stack.offset(1);
}
MachineValue::WasmStack(idx) => {
wasm_stack[idx] = Some(*stack);
stack = stack.offset(1);
}
MachineValue::WasmLocal(idx) => {
wasm_locals[idx] = Some(*stack);
stack = stack.offset(1);
}
}
}
stack = stack.offset(1); // RBP
wasm_stack.truncate(
wasm_stack
.len()
.checked_sub(state.wasm_stack_private_depth)
.unwrap(),
);
let wfs = WasmFunctionStateDump {
local_function_id: fsm.local_function_id,
wasm_inst_offset: state.wasm_inst_offset,
stack: wasm_stack,
locals: wasm_locals,
};
results.push(wfs);
}
unreachable!();
}
#[repr(u8)]
#[derive(Copy, Clone, Debug, Eq, PartialEq, Ord, PartialOrd, Hash)]
pub enum GPR {
RAX,
RCX,
RDX,
RBX,
RSP,
RBP,
RSI,
RDI,
R8,
R9,
R10,
R11,
R12,
R13,
R14,
R15,
}
#[repr(u8)]
#[derive(Copy, Clone, Debug, Eq, PartialEq, Ord, PartialOrd, Hash)]
pub enum XMM {
XMM0,
XMM1,
XMM2,
XMM3,
XMM4,
XMM5,
XMM6,
XMM7,
}
pub enum X64Register {
GPR(GPR),
XMM(XMM),
}
impl X64Register {
pub fn to_index(&self) -> RegisterIndex {
match *self {
X64Register::GPR(x) => RegisterIndex(x as usize),
X64Register::XMM(x) => RegisterIndex(x as usize + 16),
}
}
}
}