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allow resize_heap to grow heap in emscripten

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This commit is contained in:
Mark McCaskey 2019-04-08 14:44:40 -07:00
parent 7f8b1ea521
commit 6578838acd
2 changed files with 34 additions and 6 deletions
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36
lib/emscripten/src/memory.rs
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@ -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_PAGE_SIZE},
vm::Ctx,
};
/// emscripten: _emscripten_memcpy_big
pub fn _emscripten_memcpy_big(ctx: &mut Ctx, dest: u32, src: u32, len: u32) -> u32 {
@ -23,9 +26,34 @@ pub fn _emscripten_get_heap_size(ctx: &mut Ctx) -> u32 {
}
/// 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
/// 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;
if requested_size > current_memory {
let remainder = (requested_size - current_memory) as usize % WASM_PAGE_SIZE;
let delta = {
let delta = (requested_size - current_memory) as usize / WASM_PAGE_SIZE;
if remainder != 0 {
delta + 1
} else {
delta
}
};
if current_memory_pages.0 as usize + delta > WASM_MAX_PAGES {
// TODO: handle this?
debug!("Can't exceed max pages");
return 0;
}
if let Ok(v) = ctx.memory(0).grow(Pages(delta as u32)) {
return v.0;
}
}
0
}

4
lib/runtime-core/src/units.rs
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@ -4,8 +4,8 @@ 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;
/// Units of WebAssembly pages (as specified to be 65,536 bytes).
#[derive(Serialize, Deserialize, Copy, Clone, PartialEq, Eq, PartialOrd, Ord)]