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Merge #335

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335: allow resize_heap to grow heap in emscripten r=syrusakbary a=MarkMcCaskey

Emscripten programs compiled with `-s ALLOW_MEMORY_GROWTH=1` will now work

Co-authored-by: Mark McCaskey <mark@wasmer.io>
This commit is contained in:
bors[bot] 2019-04-08 23:40:37 +00:00
commit 80b809383e
2 changed files with 42 additions and 7 deletions
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43
lib/emscripten/src/memory.rs
View File

@ -1,6 +1,9 @@
use super::process::abort_with_message;
use libc::{c_int, c_void, memcpy, size_t};
use wasmer_runtime_core::vm::Ctx;
use wasmer_runtime_core::{
units::{Pages, WASM_MAX_PAGES, WASM_MIN_PAGES, WASM_PAGE_SIZE},
vm::Ctx,
};
/// emscripten: _emscripten_memcpy_big
pub fn _emscripten_memcpy_big(ctx: &mut Ctx, dest: u32, src: u32, len: u32) -> u32 {
@ -22,11 +25,41 @@ pub fn _emscripten_get_heap_size(ctx: &mut Ctx) -> u32 {
ctx.memory(0).size().bytes().0 as u32
}
// From emscripten implementation
fn align_up(mut val: usize, multiple: usize) -> usize {
if val % multiple > 0 {
val += multiple - val % multiple;
}
val
}
/// emscripten: _emscripten_resize_heap
pub fn _emscripten_resize_heap(_ctx: &mut Ctx, _requested_size: u32) -> u32 {
debug!("emscripten::_emscripten_resize_heap {}", _requested_size);
// TODO: Fix implementation
0
/// Note: this function only allows growing the size of heap
pub fn _emscripten_resize_heap(ctx: &mut Ctx, requested_size: u32) -> u32 {
debug!("emscripten::_emscripten_resize_heap {}", requested_size);
let current_memory_pages = ctx.memory(0).size();
let current_memory = current_memory_pages.bytes().0 as u32;
// implementation from emscripten
let mut new_size = usize::max(current_memory as usize, WASM_MIN_PAGES * WASM_PAGE_SIZE);
while new_size < requested_size as usize {
if new_size <= 0x2000_0000 {
new_size = align_up(new_size * 2, WASM_PAGE_SIZE);
} else {
new_size = usize::min(
align_up((3 * new_size + 0x8000_0000) / 4, WASM_PAGE_SIZE),
WASM_PAGE_SIZE * WASM_MAX_PAGES,
);
}
}
let amount_to_grow = (new_size - current_memory as usize) / WASM_PAGE_SIZE;
if let Ok(_pages_allocated) = ctx.memory(0).grow(Pages(amount_to_grow as u32)) {
debug!("{} pages allocated", _pages_allocated.0);
1
} else {
0
}
}
/// emscripten: getTotalMemory

6
lib/runtime-core/src/units.rs
View File

@ -4,8 +4,10 @@ use std::{
ops::{Add, Sub},
};
const WASM_PAGE_SIZE: usize = 65_536;
const WASM_MAX_PAGES: usize = 65_536;
pub const WASM_PAGE_SIZE: usize = 65_536;
pub const WASM_MAX_PAGES: usize = 65_536;
// From emscripten resize_heap implementation
pub const WASM_MIN_PAGES: usize = 256;
/// Units of WebAssembly pages (as specified to be 65,536 bytes).
#[derive(Serialize, Deserialize, Copy, Clone, PartialEq, Eq, PartialOrd, Ord)]