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Merge pull request #4355 from roc-lang/concat-memleak

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Fix memory leak in List.concat
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Brendan Hansknecht 2022-10-18 19:07:52 +00:00 • committed by GitHub
commit 62c9a2a8b6
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1 changed files with 41 additions and 24 deletions
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65
crates/compiler/builtins/bitcode/src/list.zig
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@ -745,37 +745,54 @@ pub fn listConcat(list_a: RocList, list_b: RocList, alignment: u32, element_widt
} else if (list_a.isUnique()) {
const total_length: usize = list_a.len() + list_b.len();
if (list_a.bytes) |source| {
const new_source = if (list_a.capacity >= total_length)
source
else
utils.unsafeReallocate(
source,
alignment,
list_a.len(),
total_length,
element_width,
);
const resized_list_a = list_a.reallocate(alignment, total_length, element_width);
if (list_b.bytes) |source_b| {
@memcpy(new_source + list_a.len() * element_width, source_b, list_b.len() * element_width);
}
// These must exist, otherwise, the lists would have been empty.
const source_a = resized_list_a.bytes orelse unreachable;
const source_b = list_b.bytes orelse unreachable;
@memcpy(source_a + list_a.len() * element_width, source_b, list_b.len() * element_width);
return RocList{ .bytes = new_source, .length = total_length, .capacity = total_length };
}
// decrement list b.
utils.decref(source_b, list_b.len(), alignment);
return resized_list_a;
} else if (list_b.isUnique()) {
const total_length: usize = list_a.len() + list_b.len();
const resized_list_b = list_b.reallocate(alignment, total_length, element_width);
// These must exist, otherwise, the lists would have been empty.
const source_a = list_a.bytes orelse unreachable;
const source_b = resized_list_b.bytes orelse unreachable;
// This is a bit special, we need to first copy the elements of list_b to the end,
// then copy the elements of list_a to the beginning.
// This first call must use mem.copy because the slices might overlap.
const byte_count_a = list_a.len() * element_width;
const byte_count_b = list_b.len() * element_width;
mem.copy(u8, source_b[byte_count_a .. byte_count_a + byte_count_b], source_b[0..byte_count_b]);
@memcpy(source_b, source_a, byte_count_a);
// decrement list a.
utils.decref(source_a, list_a.len(), alignment);
return resized_list_b;
}
const total_length: usize = list_a.len() + list_b.len();
const output = RocList.allocate(alignment, total_length, element_width);
if (output.bytes) |target| {
if (list_a.bytes) |source| {
@memcpy(target, source, list_a.len() * element_width);
}
if (list_b.bytes) |source| {
@memcpy(target + list_a.len() * element_width, source, list_b.len() * element_width);
}
}
// These must exist, otherwise, the lists would have been empty.
const target = output.bytes orelse unreachable;
const source_a = list_a.bytes orelse unreachable;
const source_b = list_b.bytes orelse unreachable;
@memcpy(target, source_a, list_a.len() * element_width);
@memcpy(target + list_a.len() * element_width, source_b, list_b.len() * element_width);
// decrement list a and b.
utils.decref(source_a, list_a.len(), alignment);
utils.decref(source_b, list_b.len(), alignment);
return output;
}