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Switch branch relaxation to a FuncCursor.

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This commit is contained in:
Jakob Stoklund Olesen
2017-08-04 16:00:48 -07:00
parent 6f024267c6
commit 378e7cfe6b
1 changed files with 19 additions and 25 deletions
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44
lib/cretonne/src/binemit/relaxation.rs
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@@ -28,7 +28,8 @@
//! ```
use binemit::CodeOffset;
use ir::{Function, DataFlowGraph, Cursor, CursorBase, InstructionData, Opcode, InstEncodings};
use cursor::{Cursor, FuncCursor};
use ir::{Function, InstructionData, Opcode};
use isa::{TargetIsa, EncInfo};
use iterators::IteratorExtras;
use result::CtonError;
@@ -55,34 +56,29 @@ pub fn relax_branches(func: &mut Function, isa: &TargetIsa) -> Result<CodeOffset
offset = 0;
// Visit all instructions in layout order
let mut pos = Cursor::new(&mut func.layout);
while let Some(ebb) = pos.next_ebb() {
let mut cur = FuncCursor::new(func);
while let Some(ebb) = cur.next_ebb() {
// Record the offset for `ebb` and make sure we iterate until offsets are stable.
if func.offsets[ebb] != offset {
assert!(func.offsets[ebb] < offset,
if cur.func.offsets[ebb] != offset {
assert!(cur.func.offsets[ebb] < offset,
"Code shrinking during relaxation");
func.offsets[ebb] = offset;
cur.func.offsets[ebb] = offset;
go_again = true;
}
while let Some(inst) = pos.next_inst() {
let enc = func.encodings.get_or_default(inst);
while let Some(inst) = cur.next_inst() {
let enc = cur.func.encodings.get_or_default(inst);
let size = encinfo.bytes(enc);
// See if this might be a branch that is out of range.
if let Some(range) = encinfo.branch_range(enc) {
if let Some(dest) = func.dfg[inst].branch_destination() {
let dest_offset = func.offsets[dest];
if let Some(dest) = cur.func.dfg[inst].branch_destination() {
let dest_offset = cur.func.offsets[dest];
if !range.contains(offset, dest_offset) {
// This is an out-of-range branch.
// Relax it unless the destination offset has not been computed yet.
if dest_offset != 0 || Some(dest) == pos.layout.entry_block() {
offset += relax_branch(&mut func.dfg,
&mut func.encodings,
&encinfo,
&mut pos,
offset,
dest_offset);
if dest_offset != 0 || Some(dest) == cur.func.layout.entry_block() {
offset += relax_branch(&mut cur, offset, dest_offset, &encinfo);
continue;
}
}
@@ -130,17 +126,15 @@ fn fallthroughs(func: &mut Function) {
///
/// Return the size of the replacement instructions up to and including the location where `pos` is
/// left.
fn relax_branch(dfg: &mut DataFlowGraph,
encodings: &mut InstEncodings,
encinfo: &EncInfo,
pos: &mut Cursor,
fn relax_branch(cur: &mut FuncCursor,
offset: CodeOffset,
dest_offset: CodeOffset)
dest_offset: CodeOffset,
encinfo: &EncInfo)
-> CodeOffset {
let inst = pos.current_inst().unwrap();
let inst = cur.current_inst().unwrap();
dbg!("Relaxing [{}] {} for {:#x}-{:#x} range",
encinfo.display(encodings[inst]),
dfg.display_inst(inst, None),
encinfo.display(cur.func.encodings[inst]),
cur.func.dfg.display_inst(inst, None),
offset,
dest_offset);
unimplemented!();