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Stop maintaining a linked list of EBB arguments.

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Now that we have a value list of the arguments, we can get rid of:

- The first_arg and last_arg members in EbbData,
- The next member in the ValueData::Arg variant.
This commit is contained in:
Jakob Stoklund Olesen
2017-04-11 12:30:37 -07:00
parent 77a26b4345
commit 20ca22f6eb
2 changed files with 23 additions and 85 deletions
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95
lib/cretonne/src/ir/dfg.rs
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@@ -276,7 +276,6 @@ enum ValueData {
ty: Type,
num: u16, // Argument number, starting from 0.
ebb: Ebb,
next: PackedOption<Value>, // Next argument to `ebb`.
},
// Value is an alias of another value.
@@ -308,7 +307,9 @@ impl<'a> Iterator for Values<'a> {
ExpandedValue::Table(index) => {
match self.dfg.extended_values[index] {
ValueData::Inst { next, .. } => next.into(),
ValueData::Arg { next, .. } => next.into(),
ValueData::Arg { .. } => {
panic!("EBB argument {} appeared in value list", prev)
}
ValueData::Alias { .. } => {
panic!("Alias value {} appeared in value list", prev)
}
@@ -696,7 +697,6 @@ impl DataFlowGraph {
ty: ty,
ebb: ebb,
num: 0,
next: None.into(),
});
self.attach_ebb_arg(ebb, val);
val
@@ -724,46 +724,20 @@ impl DataFlowGraph {
};
// Create new value identical to the old one except for the type.
let (ebb, num, new_arg) = if let ValueData::Arg { num, ebb, next, .. } = old_data {
(ebb,
num,
self.make_value(ValueData::Arg {
ty: new_type,
num: num,
ebb: ebb,
next: next,
}))
let (ebb, num) = if let ValueData::Arg { num, ebb, .. } = old_data {
(ebb, num)
} else {
panic!("old_arg: {} must be an EBB argument: {:?}",
old_arg,
old_data);
};
let new_arg = self.make_value(ValueData::Arg {
ty: new_type,
num: num,
ebb: ebb,
});
self.ebbs[ebb].args.as_mut_slice(&mut self.value_lists)[num as usize] = new_arg;
// Now fix up the linked lists.
if self.ebbs[ebb].last_arg.expand() == Some(old_arg) {
self.ebbs[ebb].last_arg = new_arg.into();
}
if self.ebbs[ebb].first_arg.expand() == Some(old_arg) {
assert_eq!(num, 0);
self.ebbs[ebb].first_arg = new_arg.into();
} else {
// We need to find the num-1 argument value and change its next link.
let arg = self.ebbs[ebb].args.as_slice(&self.value_lists)[(num - 1) as usize];
if let ExpandedValue::Table(index) = arg.expand() {
if let ValueData::Arg { ref mut next, .. } = self.extended_values[index] {
assert_eq!(next.expand(), Some(old_arg));
*next = new_arg.into();
} else {
panic!("{} is not an EBB argument", arg);
}
} else {
panic!("{} is not an EBB argument", arg);
}
}
new_arg
}
@@ -773,8 +747,6 @@ impl DataFlowGraph {
/// is to put them back on the same EBB with `attach_ebb_arg()` or change them into aliases
/// with `change_to_alias()`.
pub fn detach_ebb_args(&mut self, ebb: Ebb) -> ValueList {
self.ebbs[ebb].first_arg = None.into();
self.ebbs[ebb].last_arg = None.into();
self.ebbs[ebb].args.take()
}
@@ -786,38 +758,14 @@ impl DataFlowGraph {
///
/// In almost all cases, you should be using `append_ebb_arg()` instead of this method.
pub fn attach_ebb_arg(&mut self, ebb: Ebb, arg: Value) {
self.ebbs[ebb].args.push(arg, &mut self.value_lists);
let arg_num = match self.ebbs[ebb].last_arg.map(|v| v.expand()) {
// If last_argument is `None`, we're adding the first EBB argument.
None => {
self.ebbs[ebb].first_arg = arg.into();
0
}
// Append to the linked list of arguments.
Some(ExpandedValue::Table(idx)) => {
if let ValueData::Arg { ref mut next, num, .. } = self.extended_values[idx] {
*next = arg.into();
assert!(num < u16::MAX, "Too many arguments to EBB");
num + 1
} else {
panic!("inconsistent value table entry for EBB argument");
}
}
_ => panic!("inconsistent value table entry for EBB argument"),
};
self.ebbs[ebb].last_arg = arg.into();
let arg_num = self.ebbs[ebb].args.push(arg, &mut self.value_lists);
assert!(arg_num <= u16::MAX as usize, "Too many arguments to EBB");
// Now update `arg` itself.
let arg_ebb = ebb;
if let ExpandedValue::Table(idx) = arg.expand() {
if let ValueData::Arg {
ref mut num,
ebb,
ref mut next,
..
} = self.extended_values[idx] {
*num = arg_num;
*next = None.into();
if let ValueData::Arg { ref mut num, ebb, .. } = self.extended_values[idx] {
*num = arg_num as u16;
assert_eq!(arg_ebb, ebb, "{} should already belong to EBB", arg);
return;
}
@@ -835,24 +783,11 @@ impl DataFlowGraph {
struct EbbData {
// List of arguments to this EBB.
args: ValueList,
// First argument to this EBB, or `None` if the block has no arguments.
//
// The arguments are all `ValueData::Argument` entries that form a linked list from `first_arg`
// to `last_arg`.
first_arg: PackedOption<Value>,
// Last argument to this EBB, or `None` if the block has no arguments.
last_arg: PackedOption<Value>,
}
impl EbbData {
fn new() -> EbbData {
EbbData {
args: ValueList::new(),
first_arg: None.into(),
last_arg: None.into(),
}
EbbData { args: ValueList::new() }
}
}