fix(armv7): split record_header_indices loop to work around rustc/LLVM bug

rustc issue: https://github.com/rust-lang/rust/issues/55105

Steps to reproduce:

```
rustup target add armv7-linux-androideabi
RUSTFLAGS="-Ctarget-feature=+neon" cargo build --target armv7-linux-androideabi --release
```

Output without this change:

```
   Compiling hyper v0.12.11 (/home/simon/projects/servo-deps/hyper)
LLVM ERROR: ran out of registers during register allocation
error: Could not compile `hyper`.
```
This commit is contained in:
Simon Sapin
2018-10-16 19:17:55 +02:00
committed by Sean McArthur
parent 66a857d801
commit 30a4f2376a

View File

@@ -920,13 +920,41 @@ struct HeaderIndices {
fn record_header_indices(bytes: &[u8], headers: &[httparse::Header], indices: &mut [HeaderIndices]) {
let bytes_ptr = bytes.as_ptr() as usize;
for (header, indices) in headers.iter().zip(indices.iter_mut()) {
let name_start = header.name.as_ptr() as usize - bytes_ptr;
let name_end = name_start + header.name.len();
indices.name = (name_start, name_end);
let value_start = header.value.as_ptr() as usize - bytes_ptr;
let value_end = value_start + header.value.len();
indices.value = (value_start, value_end);
// FIXME: This should be a single plain `for` loop.
// Splitting it is a work-around for https://github.com/rust-lang/rust/issues/55105
macro_rules! split_loops_if {
(
cfg($($cfg: tt)+)
for $i: pat in ($iter: expr) {
$body1: block
$body2: block
}
) => {
for $i in $iter {
$body1
#[cfg(not($($cfg)+))] $body2
}
#[cfg($($cfg)+)]
for $i in $iter {
$body2
}
}
}
split_loops_if! {
cfg(all(target_arch = "arm", target_feature = "v7", target_feature = "neon"))
for (header, indices) in (headers.iter().zip(indices.iter_mut())) {
{
let name_start = header.name.as_ptr() as usize - bytes_ptr;
let name_end = name_start + header.name.len();
indices.name = (name_start, name_end);
}
{
let value_start = header.value.as_ptr() as usize - bytes_ptr;
let value_end = value_start + header.value.len();
indices.value = (value_start, value_end);
}
}
}
}