mirror of
https://github.com/servo/servo.git
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959ce482dd
We’ve been bitten before by symbol names changing: https://github.com/servo/heapsize/pull/46 and upstream is planning to stop using jemalloc by default: https://github.com/rust-lang/rust/issues/33082#issuecomment-309781465 So use the (relatively) new `#[global_allocator]` attribute to explicitly select the system allocator on Windows and jemalloc (now in an external crate) on other platforms. This choice matches current defaults.
62 lines
1.8 KiB
Rust
62 lines
1.8 KiB
Rust
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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//! Selecting the default global allocator for Servo
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#![cfg_attr(all(feature = "unstable", windows), feature(alloc_system, allocator_api))]
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#![cfg_attr(feature = "unstable", feature(global_allocator))]
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#[cfg(feature = "unstable")]
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#[global_allocator]
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static ALLOC: platform::Allocator = platform::Allocator;
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pub use platform::usable_size;
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#[cfg(all(feature = "unstable", not(windows)))]
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mod platform {
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extern crate jemallocator;
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pub use self::jemallocator::Jemalloc as Allocator;
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use std::os::raw::c_void;
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/// Get the size of a heap block.
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pub unsafe extern "C" fn usable_size(ptr: *const c_void) -> usize {
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jemallocator::usable_size(ptr)
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}
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}
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#[cfg(all(feature = "unstable", windows))]
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mod platform {
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extern crate alloc_system;
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extern crate kernel32;
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pub use self::alloc_system::System as Allocator;
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use self::kernel32::{GetProcessHeap, HeapSize, HeapValidate};
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use std::os::raw::c_void;
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/// Get the size of a heap block.
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pub unsafe extern "C" fn usable_size(mut ptr: *const c_void) -> usize {
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let heap = GetProcessHeap();
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if HeapValidate(heap, 0, ptr) == 0 {
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ptr = *(ptr as *const *const c_void).offset(-1);
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}
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HeapSize(heap, 0, ptr) as usize
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}
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}
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#[cfg(not(feature = "unstable"))]
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mod platform {
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use std::os::raw::c_void;
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/// Without `#[global_allocator]` we cannot be certain of what allocator is used
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/// or how it is linked. We therefore disable memory reporting. (Return zero.)
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pub unsafe extern "C" fn usable_size(_ptr: *const c_void) -> usize {
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0
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}
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}
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