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Fix some issues with the use of stack depth

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This commit is contained in:
Jef
2018-12-19 14:42:00 +01:00
parent 3b5c11a92a
commit f91b9072de
2 changed files with 14 additions and 5 deletions
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17
src/backend.rs
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@@ -468,11 +468,15 @@ pub fn reset_block(ctx: &mut Context, parent_block_state: BlockState) {
}
pub fn end_block(ctx: &mut Context, parent_block_state: BlockState) {
// TODO: This is currently never called, but is important for if we want to
// TODO: This should currently never be called, but is important for if we want to
// have a more complex stack spilling scheme.
assert_eq!(
ctx.block_state.depth, parent_block_state.depth,
"Imbalanced pushes and pops"
);
if ctx.block_state.depth != parent_block_state.depth {
dynasm!(ctx.asm
; add rsp, (ctx.block_state.depth.0 - parent_block_state.depth.0) as i32
; add rsp, ((ctx.block_state.depth.0 - parent_block_state.depth.0) * WORD_SIZE) as i32
);
}
@@ -587,8 +591,9 @@ fn put_stack_val_into(ctx: &mut Context, val: StackValue, dst: ValueLocation) {
pub fn drop(ctx: &mut Context) {
match ctx.block_state.stack.pop().expect("Stack is empty") {
StackValue::Pop => {
ctx.block_state.depth.free(1);
dynasm!(ctx.asm
; add rsp, WORD_SIZE as i32
; add rsp, WORD_SIZE as i32
);
}
StackValue::Temp(gpr) => free_value(ctx, Value::Temp(gpr)),
@@ -948,7 +953,7 @@ macro_rules! cmp {
cmp!(i32_eq, sete, |a, b| a == b);
cmp!(i32_neq, setne, |a, b| a != b);
// TODO: `dynasm-rs` inexplicably doesn't support setb
// `dynasm-rs` inexplicably doesn't support setb but `setnae` (and `setc`) are synonymous
cmp!(i32_lt_u, setnae, |a, b| (a as u32) < (b as u32));
cmp!(i32_le_u, setbe, |a, b| (a as u32) <= (b as u32));
cmp!(i32_gt_u, seta, |a, b| (a as u32) > (b as u32));
@@ -1021,6 +1026,7 @@ fn copy_value(ctx: &mut Context, src: ValueLocation, dst: ValueLocation) {
; mov Rq(out_reg), i
);
}
// TODO: Have separate `ReadLocation` and `WriteLocation`?
(_, ValueLocation::Immediate(_)) => panic!("Tried to copy to an immediate value!"),
}
}
@@ -1083,7 +1089,6 @@ fn free_register(ctx: &mut Context, reg: GPR) {
// For now it's impossible for a local to be in RAX but that might be
// possible in the future, so we check both cases.
Some(ValueLocation::Reg(r)) if r == reg => {
ctx.block_state.depth.reserve(1);
*stack_val = StackValue::Pop;
out = Some(*stack_val);
@@ -1105,6 +1110,7 @@ fn free_register(ctx: &mut Context, reg: GPR) {
);
}
StackValue::Pop => {
ctx.block_state.depth.reserve(1);
// TODO: Ideally we should do proper stack allocation so we
// don't have to check this at all (i.e. order on the
// physical stack and order on the logical stack should
@@ -1195,6 +1201,7 @@ fn pass_outgoing_args(ctx: &mut Context, arity: u32, return_arity: u32) -> CallC
fn post_call_cleanup(ctx: &mut Context, mut cleanup: CallCleanup) {
if cleanup.stack_depth > 0 {
let size = cleanup.stack_depth * WORD_SIZE as i32;
ctx.block_state.depth.free(cleanup.stack_depth as _);
dynasm!(ctx.asm
; add rsp, size
);