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Fix WASM for LLVM6 #17

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Merged
merged 1 commit into from
Feb 12, 2018
Merged

Fix WASM for LLVM6 #17

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18 changes: 4 additions & 14 deletions wee_alloc/src/imp_wasm32.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -4,25 +4,15 @@ use core::cell::UnsafeCell;
use units::Pages;

extern "C" {
#[link_name = "llvm.wasm.current.memory.i32"]
fn current_memory() -> usize;

// TODO: this intrinsic actually returns the previous limit, but LLVM
// doesn't expose that right now. When we upgrade LLVM stop using
// `current_memory` above. Also handle `-1` as an allocation failure.
#[link_name = "llvm.wasm.grow.memory.i32"]
fn grow_memory(pages: usize);
}

unsafe fn get_base_pointer() -> *mut u8 {
(current_memory() * PAGE_SIZE.0) as _
fn grow_memory(pages: usize) -> i32;
}

pub(crate) unsafe fn alloc_pages(n: Pages) -> *mut u8 {
let ptr = get_base_pointer();
let ptr = grow_memory(n.0);
extra_assert!(ptr != -1);
let ptr = (ptr as usize * PAGE_SIZE.0) as _;
assert_is_word_aligned(ptr);
extra_assert!(!ptr.is_null());
grow_memory(n.0);
ptr
}

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