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Don't allocate context if it's unused

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This commit is contained in:
Jef
2019-01-17 14:34:34 +01:00
parent e0f032a0e5
commit d06be92a4e
3 changed files with 80 additions and 20 deletions
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60
src/backend.rs
View File

@@ -1036,14 +1036,55 @@ impl Context<'_> {
cmp_i64!(i64_gt_s, setg, setnge, |a, b| a > b);
cmp_i64!(i64_ge_s, setge, setng, |a, b| a >= b);
// TODO: Should we do this logic in `eq` and just have this delegate to `eq`?
// That would mean that `eqz` and `eq` with a const 0 argument don't
// result in different code.
pub fn i32_eqz(&mut self) {
self.push(Value::Immediate(0));
self.i32_eq();
let val = self.pop();
if let Value::Immediate(i) = val {
self.push(Value::Immediate(if i == 0 { 1 } else { 0 }));
return;
}
let (reg, needs_release) = self.into_reg(val);
let out = self.block_state.regs.take_scratch_gpr();
dynasm!(self.asm
; xor Rd(out), Rd(out)
; test Rd(reg), Rd(reg)
; setz Rb(out)
);
if needs_release {
self.block_state.regs.release_scratch_gpr(reg);
}
self.push(Value::Temp(out));
}
pub fn i64_eqz(&mut self) {
self.push(Value::Immediate(0));
self.i64_eq();
let val = self.pop();
if let Value::Immediate(i) = val {
self.push(Value::Immediate(if i == 0 { 1 } else { 0 }));
return;
}
let (reg, needs_release) = self.into_reg(val);
let out = self.block_state.regs.take_scratch_gpr();
dynasm!(self.asm
; xor Rd(out), Rd(out)
; test Rq(reg), Rq(reg)
; setz Rb(out)
);
if needs_release {
self.block_state.regs.release_scratch_gpr(reg);
}
self.push(Value::Temp(out));
}
/// Pops i32 predicate and branches to the specified label
@@ -2133,7 +2174,8 @@ impl Context<'_> {
pub fn start_function(&mut self, arguments: u32, locals: u32) -> FunctionEnd {
// To support `vmctx`
let arguments = arguments + 1;
let (reg_args, locals_in_gprs) = ARGS_IN_GPRS.split_at((arguments as usize).min(ARGS_IN_GPRS.len()));
let (reg_args, locals_in_gprs) =
ARGS_IN_GPRS.split_at((arguments as usize).min(ARGS_IN_GPRS.len()));
let reg_locals = &locals_in_gprs[..(locals as usize).min(locals_in_gprs.len())];
// We need space to store the register arguments if we need to call a function
@@ -2144,8 +2186,12 @@ impl Context<'_> {
let aligned_stack_slots = (stack_slots + 1) & !1;
let frame_size: i32 = aligned_stack_slots as i32 * WORD_SIZE as i32;
self.block_state.locals.register_locals =
reg_args.iter().chain(reg_locals).cloned().map(ArgLoc::Register).collect();
self.block_state.locals.register_locals = reg_args
.iter()
.chain(reg_locals)
.cloned()
.map(ArgLoc::Register)
.collect();
self.block_state.locals.num_stack_args = arguments.saturating_sub(ARGS_IN_GPRS.len() as _);
self.block_state.locals.num_local_stack_slots = stack_slots;
self.block_state.return_register = Some(RAX);

15
src/module.rs
View File

@@ -135,6 +135,7 @@ impl TranslatedModule {
.extend(Layout::array::<u8>(mem_size * WASM_PAGE_SIZE).unwrap())
.unwrap();
let ctx = if mem_size > 0 || slice.len > 0 {
let ptr = unsafe { alloc::alloc_zeroed(layout) } as *mut VmCtx;
unsafe {
@@ -144,9 +145,14 @@ impl TranslatedModule {
}
}
Some(Allocation { ptr, layout })
} else {
None
};
ExecutableModule {
module: self,
context: Allocation { ptr, layout },
context: ctx,
}
}
@@ -184,7 +190,7 @@ pub enum ExecutionError {
pub struct ExecutableModule {
module: TranslatedModule,
context: Allocation<VmCtx>,
context: Option<Allocation<VmCtx>>,
}
impl ExecutableModule {
@@ -216,7 +222,10 @@ impl ExecutableModule {
Ok(unsafe {
args.call(
Args::into_func(start_buf),
self.context.ptr as *const VmCtx as *const u8,
self.context
.as_ref()
.map(|ctx| ctx.ptr as *const VmCtx as *const u8)
.unwrap_or(std::ptr::null()),
)
})
}

13
src/tests.rs
View File

@@ -116,6 +116,7 @@ mod op32 {
unop_test!(clz, u32::leading_zeros);
unop_test!(ctz, u32::trailing_zeros);
unop_test!(popcnt, u32::count_ones);
unop_test!(eqz, |a: u32| if a == 0 { 1 } else { 0 });
binop_test!(add, i32::wrapping_add);
binop_test!(sub, i32::wrapping_sub);
@@ -194,31 +195,34 @@ mod op64 {
macro_rules! unop_test {
($name:ident, $func:expr) => {
unop_test!($name, $func, i64);
};
($name:ident, $func:expr, $out_ty:ty) => {
mod $name {
use super::{translate_wat, ExecutableModule};
use std::sync::Once;
lazy_static! {
static ref AS_PARAM: ExecutableModule = translate_wat(
concat!("(module (func (param i64) (result i64)
concat!("(module (func (param i64) (result ",stringify!($out_ty),")
(i64.",stringify!($name)," (get_local 0))))"),
);
}
quickcheck! {
fn as_param(a: u64) -> bool {
AS_PARAM.execute_func::<(u64,), u64>(0, (a,)) == Ok($func(a))
AS_PARAM.execute_func::<(u64,), $out_ty>(0, (a,)) == Ok($func(a))
}
fn lit(a: u64) -> bool {
let translated = translate_wat(&format!(concat!("
(module (func (result i64)
(module (func (result ",stringify!($out_ty),")
(i64.",stringify!($name)," (i64.const {val}))))
"), val = a));
static ONCE: Once = Once::new();
ONCE.call_once(|| translated.disassemble());
translated.execute_func::<(), u64>(0, ()) == Ok($func(a))
translated.execute_func::<(), $out_ty>(0, ()) == Ok($func(a))
}
}
}
@@ -228,6 +232,7 @@ mod op64 {
unop_test!(clz, |a: u64| a.leading_zeros() as _);
unop_test!(ctz, |a: u64| a.trailing_zeros() as _);
unop_test!(popcnt, |a: u64| a.count_ones() as _);
unop_test!(eqz, |a: u64| if a == 0 { 1 } else { 0 }, i32);
binop_test!(add, i64::wrapping_add);
binop_test!(sub, i64::wrapping_sub);