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[WIP]

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This commit is contained in:
bjorn3
2019-06-27 20:29:51 +02:00
committed by Dan Gohman
parent 954a2007d2
commit 44ecc9c3d0
1 changed files with 64 additions and 42 deletions
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106
cranelift/codegen/src/legalizer/mod.rs
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@@ -21,6 +21,7 @@ use crate::ir::{self, InstBuilder, MemFlags};
use crate::isa::TargetIsa;
use crate::predicates;
use crate::timing;
use std::vec::Vec;
mod boundary;
mod call;
@@ -36,24 +37,29 @@ use self::heap::expand_heap_addr;
use self::libcall::expand_as_libcall;
use self::table::expand_table_addr;
/// Legalize `inst` for `isa`. Return true if any changes to the code were
/// made; return false if the instruction was successfully encoded as is.
enum LegalizeInstResult {
Done,
Legalized,
SplitLegalizePending,
}
/// Legalize `inst` for `isa`.
fn legalize_inst(
inst: ir::Inst,
pos: &mut FuncCursor,
cfg: &mut ControlFlowGraph,
isa: &dyn TargetIsa,
) -> bool {
) -> LegalizeInstResult {
let opcode = pos.func.dfg[inst].opcode();
// Check for ABI boundaries that need to be converted to the legalized signature.
if opcode.is_call() {
if boundary::handle_call_abi(inst, pos.func, cfg) {
return true;
return LegalizeInstResult::Legalized;
}
} else if opcode.is_return() {
if boundary::handle_return_abi(inst, pos.func, cfg) {
return true;
return LegalizeInstResult::Legalized;
}
} else if opcode.is_branch() {
split::simplify_branch_arguments(&mut pos.func.dfg, inst);
@@ -65,48 +71,48 @@ fn legalize_inst(
_ => panic!("Expected isplit: {}", pos.func.dfg.display_inst(inst, None)),
};
let should_replace = match pos.func.dfg.value_def(arg) {
match pos.func.dfg.value_def(arg) {
ir::ValueDef::Result(inst, num) => {
if let ir::InstructionData::Binary { opcode, args, .. } = pos.func.dfg[inst] {
opcode == ir::Opcode::Iconcat
if opcode != ir::Opcode::Iconcat {
return LegalizeInstResult::SplitLegalizePending;
}
} else {
// `arg` was not created by an `iconcat` instruction. Don't try to resolve it,
// as otherwise `split::isplit` will re-insert the original `isplit`, causing
// an endless loop.
false
return LegalizeInstResult::SplitLegalizePending;
}
}
ir::ValueDef::Param(ebb, num) => true,
};
if should_replace {
let res = pos.func.dfg.inst_results(inst).to_vec();
assert_eq!(res.len(), 2);
let (resl, resh) = (res[0], res[1]); // Prevent borrowck error
dbg!(pos.position());
// Remove old isplit
pos.func.dfg.clear_results(inst);
pos.remove_inst();
dbg!(pos.position());
let curpos = pos.position();
let srcloc = pos.srcloc();
let (xl, xh) = split::isplit(pos.func, cfg, curpos, srcloc, arg);
pos.func.dfg.change_to_alias(resl, xl);
pos.func.dfg.change_to_alias(resh, xh);
dbg!(&pos.func);
return true;
ir::ValueDef::Param(ebb, num) => {},
}
let res = pos.func.dfg.inst_results(inst).to_vec();
assert_eq!(res.len(), 2);
let (resl, resh) = (res[0], res[1]); // Prevent borrowck error
dbg!(pos.position());
// Remove old isplit
pos.func.dfg.clear_results(inst);
pos.remove_inst();
dbg!(pos.position());
let curpos = pos.position();
let srcloc = pos.srcloc();
let (xl, xh) = split::isplit(pos.func, cfg, curpos, srcloc, arg);
pos.func.dfg.change_to_alias(resl, xl);
pos.func.dfg.change_to_alias(resh, xh);
dbg!(&pos.func);
return LegalizeInstResult::Legalized;
}
match pos.func.update_encoding(inst, isa) {
Ok(()) => false,
Ok(()) => LegalizeInstResult::Done,
Err(action) => {
// We should transform the instruction into legal equivalents.
// If the current instruction was replaced, we need to double back and revisit
@@ -115,12 +121,16 @@ fn legalize_inst(
// There's a risk of infinite looping here if the legalization patterns are
// unsound. Should we attempt to detect that?
if action(inst, pos.func, cfg, isa) {
return true;
return LegalizeInstResult::Legalized;
}
// We don't have any pattern expansion for this instruction either.
// Try converting it to a library call as a last resort.
expand_as_libcall(inst, pos.func, isa)
if expand_as_libcall(inst, pos.func, isa) {
LegalizeInstResult::Legalized
} else {
LegalizeInstResult::Done
}
}
}
}
@@ -139,6 +149,7 @@ pub fn legalize_function(func: &mut ir::Function, cfg: &mut ControlFlowGraph, is
func.encodings.resize(func.dfg.num_insts());
let mut pos = FuncCursor::new(func);
let mut pending_splits = Vec::new();
// Process EBBs in layout order. Some legalization actions may split the current EBB or append
// new ones to the end. We need to make sure we visit those new EBBs too.
@@ -148,16 +159,27 @@ pub fn legalize_function(func: &mut ir::Function, cfg: &mut ControlFlowGraph, is
let mut prev_pos = pos.position();
while let Some(inst) = pos.next_inst() {
if legalize_inst(inst, &mut pos, cfg, isa) {
// Go back and legalize the inserted return value conversion instructions.
pos.set_position(prev_pos);
} else {
match legalize_inst(inst, &mut pos, cfg, isa) {
// Remember this position in case we need to double back.
prev_pos = pos.position();
LegalizeInstResult::Done => prev_pos = pos.position(),
// Go back and legalize the inserted return value conversion instructions.
LegalizeInstResult::Legalized => pos.set_position(prev_pos),
// The argument of a `isplit` or `vsplit` instruction didn't resolve to a
// `iconcat` or `vconcat` instruction. Try again after legalizing the rest of
// the instructions.
LegalizeInstResult::SplitLegalizePending => pending_splits.push(inst),
}
}
}
// Try legalizing `isplit` and `vsplit` instructions, which could not previously be legalized.
for inst in pending_splits {
//pos.goto_inst(inst);
//legalize_inst(inst, &mut pos, cfg, isa);
}
// Now that we've lowered all br_tables, we don't need the jump tables anymore.
if !isa.flags().jump_tables_enabled() {
pos.func.jump_tables.clear();