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Properly preserve and restore CFA state in FDE (#1373)

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* Properly preserve and restore CFA state in FDE
This commit is contained in:
Yury Delendik
2020-02-03 16:08:40 -06:00
committed by GitHub
parent 3502cd3cd1
commit 169dbef784
2 changed files with 99 additions and 25 deletions
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39
cranelift/codegen/src/isa/x86/abi.rs
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@@ -835,25 +835,7 @@ fn insert_common_epilogues(
pos.goto_last_inst(ebb);
if let Some(inst) = pos.current_inst() {
if pos.func.dfg[inst].opcode().is_return() {
if let (Some(ref mut frame_layout), ref func_layout) =
(pos.func.frame_layout.as_mut(), &pos.func.layout)
{
// Figure out if we need to insert end-of-function-aware frame layout information.
let following_inst = func_layout
.next_ebb(ebb)
.and_then(|next_ebb| func_layout.first_inst(next_ebb));
if let Some(following_inst) = following_inst {
frame_layout
.instructions
.insert(inst, vec![FrameLayoutChange::Preserve].into_boxed_slice());
frame_layout.instructions.insert(
following_inst,
vec![FrameLayoutChange::Restore].into_boxed_slice(),
);
}
}
let is_last = pos.func.layout.last_ebb() == Some(ebb);
insert_common_epilogue(
inst,
stack_size,
@@ -861,6 +843,7 @@ fn insert_common_epilogues(
reg_type,
csrs,
isa,
is_last,
cfa_state.clone(),
);
}
@@ -877,6 +860,7 @@ fn insert_common_epilogue(
reg_type: ir::types::Type,
csrs: &RegisterSet,
isa: &dyn TargetIsa,
is_last: bool,
mut cfa_state: Option<CFAState>,
) {
let word_size = isa.pointer_bytes() as isize;
@@ -931,10 +915,16 @@ fn insert_common_epilogue(
assert_eq!(cfa_state.current_depth, -word_size);
assert_eq!(cfa_state.cf_ptr_offset, word_size);
// Inserting preserve CFA state operation after FP pop instructions.
let new_cfa = FrameLayoutChange::CallFrameAddressAt {
reg: cfa_state.cf_ptr_reg,
offset: cfa_state.cf_ptr_offset,
};
let new_cfa = if is_last {
vec![new_cfa]
} else {
vec![FrameLayoutChange::Preserve, new_cfa]
};
frame_layout
.instructions
@@ -943,10 +933,17 @@ fn insert_common_epilogue(
*insts = insts
.iter()
.cloned()
.chain(std::iter::once(new_cfa))
.chain(new_cfa.clone().into_iter())
.collect::<Box<[_]>>();
})
.or_insert_with(|| Box::new([new_cfa]));
.or_insert_with(|| new_cfa.into_boxed_slice());
if !is_last {
// Inserting restore CFA state operation after each return.
frame_layout
.instructions
.insert(inst, vec![FrameLayoutChange::Restore].into_boxed_slice());
}
}
}