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Improve liballoc_jemalloc {re}alloc_excess #45482

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42 changes: 33 additions & 9 deletions src/liballoc_jemalloc/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -67,6 +67,10 @@ mod contents {
target_os = "dragonfly", target_os = "windows", target_env = "musl"),
link_name = "je_nallocx")]
fn nallocx(size: size_t, flags: c_int) -> size_t;
#[cfg_attr(any(target_os = "macos", target_os = "android", target_os = "ios",
target_os = "dragonfly", target_os = "windows", target_env = "musl"),
link_name = "je_sallocx")]
fn sallocx(size: size_t, flags: c_int) -> size_t;
}

const MALLOCX_ZERO: c_int = 0x40;
Expand Down Expand Up @@ -201,27 +205,47 @@ mod contents {
align: usize,
excess: *mut usize,
err: *mut u8) -> *mut u8 {
let p = __rde_alloc(size, align, err);
if !p.is_null() {
*excess = size;
let flags = align_to_flags(align);
let ptr = mallocx(size as size_t, flags) as *mut u8;
if ptr.is_null() {
let layout = Layout::from_size_align_unchecked(size, align);
ptr::write(err as *mut AllocErr,
AllocErr::Exhausted { request: layout });
} else {
*excess = sallocx(size as size_t, flags) as usize;
}
return p
ptr
}

#[no_mangle]
#[linkage = "external"]
pub unsafe extern fn __rde_realloc_excess(ptr: *mut u8,
old_size: usize,
_old_size: usize,
old_align: usize,
new_size: usize,
new_align: usize,
excess: *mut usize,
err: *mut u8) -> *mut u8 {
let p = __rde_realloc(ptr, old_size, old_align, new_size, new_align, err);
if !p.is_null() {
*excess = new_size;
if new_align != old_align {
ptr::write(
err as *mut AllocErr,
AllocErr::Unsupported { details: "can't change alignments" },
);
return 0 as *mut u8
}
return p

let flags = align_to_flags(new_align);
let ptr = rallocx(ptr as *mut c_void, new_size as size_t, flags) as *mut u8;
if ptr.is_null() {
let layout = Layout::from_size_align_unchecked(new_size, new_align);
ptr::write(
err as *mut AllocErr,
AllocErr::Exhausted { request: layout },
);
} else {
*excess = sallocx(new_size as size_t, flags) as usize;
}
ptr
}

#[no_mangle]
Expand Down