ai-space/craft-anything
3
0
Fork 0
mirror of https://github.com/storytold/craft-anything.git synced 2026-11-05 20:47:45 +01:00
Code Issues Packages Projects Releases Wiki Activity

ARM32 pseudo-C keeps call return values in r0 (#380)

Browse Source 
ARM32 and Thumb pseudo-C returns a call's result in r0 instead of an x86 register. Fixes #278.
This commit is contained in:
phatloi0010
2026-11-02 23:08:39 +07:00
committed by GitHub
parent ea8f4b82b8
commit 8fb98ceea7
1 changed files with 51 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files
crates/disasm/src/pseudo.rs
+51 -2
View File
@@ -521,7 +521,11 @@ impl Lifter<'_> {
}
fn ret_canon(&self) -> String {
if self.mode == Mode::A64 { "x0".into() } else { "rax".into() }
match self.mode {
Mode::A64 => "x0".into(),
Mode::A32 | Mode::T32 => "r0".into(),
_ => "rax".into(),
}
}
fn ret_reg_name(&self) -> String {
@@ -1046,7 +1050,7 @@ pub fn lift(img: &Image, prog: &Program, f: &Function, names: &dyn Fn(u64) -> Op
'outer: for v in per_block.iter().rev() {
for i in v.iter().rev() {
if matches!(i.flow, Flow::Call { .. } | Flow::IndirectCall { .. }) {
ret_reg = if mode == Mode::A64 { "x0".into() } else { "rax".into() };
ret_reg = ret_canon.into();
break 'outer;
}
if i.writes.iter().any(|w| w == ret_canon)
@@ -1294,4 +1298,49 @@ mod tests {
}
}
}
#[test]
fn arm32_calls_keep_their_return_value_in_r0() {
use craft_anything_formats::Arch;
fn words(ws: &[u32]) -> Vec<u8> {
ws.iter().flat_map(|w| w.to_le_bytes()).collect()
}
fn arm_elf(code: &[u8], thumb: bool) -> Vec<u8> {
let mut b = vec![0u8; 0x100];
b[0..7].copy_from_slice(b"\x7fELF\x01\x01\x01");
for (o, v) in [(16, 2u16), (18, 40), (40, 52), (42, 32), (44, 1)] {
b[o..o + 2].copy_from_slice(&v.to_le_bytes());
}
let n = code.len() as u32;
for (o, v) in [(20, 1u32), (24, 0x1000 | u32::from(thumb)), (28, 52), (36, 0x0500_0000), (52, 1)] {
b[o..o + 4].copy_from_slice(&v.to_le_bytes());
}
for (o, v) in [(56, 0x100u32), (60, 0x1000), (64, 0x1000), (68, n), (72, n), (76, 5), (80, 0x100)] {
b[o..o + 4].copy_from_slice(&v.to_le_bytes());
}
b.extend_from_slice(code);
b
}
fn lift_entry(image: Image) -> String {
let program = Program::analyze(&image, &Limits::default(), &NoControl).unwrap();
let f = program.functions.get(&0x1000).unwrap();
lift(&image, &program, f, &|_| None).text
}
let call_ret = words(&[0xe92d_4010, 0xeb00_0001, 0xe8bd_8010, 0xe320_f000, 0xe3a0_0007, 0xe12f_ff1e]);
let used_call = words(&[0xe92d_4010, 0xeb00_0002, 0xe280_1001, 0xe1a0_0001, 0xe8bd_8010, 0xe3a0_0007, 0xe12f_ff1e]);
let leaf = words(&[0xe3a0_0007, 0xe12f_ff1e]);
let ar = lift_entry(Image::raw(Arc::from(call_ret.clone()), Arch::Arm, 0x1000));
let au = lift_entry(Image::raw(Arc::from(used_call), Arch::Arm, 0x1000));
let al = lift_entry(Image::raw(Arc::from(leaf), Arch::Arm, 0x1000));
let ae = lift_entry(Image::parse(Arc::from(arm_elf(&call_ret, false))).unwrap());
let tr = lift_entry(Image::parse(Arc::from(arm_elf(&[0x10, 0xb5, 0x98, 0x47, 0x10, 0xbd], true))).unwrap());
assert!(ar.contains("return r0;") && !ar.contains("rax"), "{ar}");
assert!(ae.contains("return r0;") && !ae.contains("rax"), "{ae}");
assert!(tr.contains("return r0;") && !tr.contains("rax"), "{tr}");
assert!(au.contains("r0 = sub_1014();") && au.contains("r1 = r0 + 1;") && au.contains("return r0;"), "{au}");
assert!(al.contains("r0 = 7;") && al.contains("return r0;") && !al.contains("rax"), "{al}");
}
}