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/*
* Released under the terms of the Apache 2.0 license with LLVM
* exception. See `LICENSE` for details.
*/
#![no_main]
use regalloc2::fuzzing::arbitrary::{Arbitrary, Result, Unstructured};
use regalloc2::fuzzing::fuzz_target;
use regalloc2::fuzzing::moves::{MoveAndScratchResolver, ParallelMoves};
use regalloc2::{Allocation, PReg, RegClass, SpillSlot};
use std::collections::{HashMap, HashSet};
fn is_stack_alloc(alloc: Allocation) -> bool {
// Treat registers 20..=29 as fixed stack slots.
if let Some(reg) = alloc.as_reg() {
reg.index() > 20
} else {
alloc.is_stack()
}
}
#[derive(Clone, Debug)]
struct TestCase {
moves: Vec<(Allocation, Allocation)>,
available_pregs: Vec<Allocation>,
}
impl Arbitrary<'_> for TestCase {
fn arbitrary(u: &mut Unstructured) -> Result<Self> {
let mut ret = TestCase {
moves: vec![],
available_pregs: vec![],
};
let mut written = HashSet::new();
// An arbitrary sequence of moves between registers 0 to 29
// inclusive.
while bool::arbitrary(u)? {
let src = if bool::arbitrary(u)? {
let reg = u.int_in_range(0..=29)?;
Allocation::reg(PReg::new(reg, RegClass::Int))
} else {
let slot = u.int_in_range(0..=31)?;
Allocation::stack(SpillSlot::new(slot))
};
let dst = if bool::arbitrary(u)? {
let reg = u.int_in_range(0..=29)?;
Allocation::reg(PReg::new(reg, RegClass::Int))
} else {
let slot = u.int_in_range(0..=31)?;
Allocation::stack(SpillSlot::new(slot))
};
// Stop if we are going to write a reg more than once:
// that creates an invalid parallel move set.
if written.contains(&dst) {
break;
}
written.insert(dst);
ret.moves.push((src, dst));
}
// We might have some unallocated registers free for scratch
// space...
for i in 0..u.int_in_range(0..=2)? {
let reg = PReg::new(30 + i, RegClass::Int);
ret.available_pregs.push(Allocation::reg(reg));
}
Ok(ret)
}
}
fuzz_target!(|testcase: TestCase| {
let _ = env_logger::try_init();
let mut par = ParallelMoves::new();
for &(src, dst) in &testcase.moves {
par.add(src, dst, ());
}
let moves = par.resolve();
log::trace!("raw resolved moves: {:?}", moves);
// Resolve uses of scratch reg and stack-to-stack moves with the
// scratch resolver.
let mut avail = testcase.available_pregs.clone();
let find_free_reg = || avail.pop();
let mut next_slot = 32;
let get_stackslot = || {
let slot = next_slot;
next_slot += 1;
Allocation::stack(SpillSlot::new(slot))
};
let preferred_victim = PReg::new(0, RegClass::Int);
let scratch_resolver = MoveAndScratchResolver {
find_free_reg,
get_stackslot,
is_stack_alloc,
borrowed_scratch_reg: preferred_victim,
};
let moves = scratch_resolver.compute(moves);
log::trace!("resolved moves: {:?}", moves);
// Compute the final source reg for each dest reg in the original
// parallel-move set.
let mut final_src_per_dest: HashMap<Allocation, Allocation> = HashMap::new();
for &(src, dst) in &testcase.moves {
final_src_per_dest.insert(dst, src);
}
log::trace!("expected final state: {:?}", final_src_per_dest);
// Simulate the sequence of moves.
let mut locations: HashMap<Allocation, Allocation> = HashMap::new();
for (src, dst, _) in moves {
let data = locations.get(&src).cloned().unwrap_or(src);
locations.insert(dst, data);
}
log::trace!("simulated final state: {:?}", locations);
// Assert that the expected register-moves occurred.
for (reg, data) in locations {
if let Some(&expected_data) = final_src_per_dest.get(®) {
assert_eq!(expected_data, data);
} else {
if data != reg {
// If not just the original value, then this location
// has been modified, but it was not part of the
// original parallel move. It must have been an
// available preg or a scratch stackslot.
assert!(
testcase.available_pregs.contains(®)
|| (reg.is_stack() && reg.as_stack().unwrap().index() >= 32)
);
}
}
}
});
|
