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use crate::sys::{MemoryType, Pages, TableType};
use std::ptr::NonNull;
use wasmer_compiler::Tunables;
use wasmer_types::{PointerWidth, Target};
use wasmer_vm::MemoryError;
use wasmer_vm::{
MemoryStyle, TableStyle, VMMemory, VMMemoryDefinition, VMTable, VMTableDefinition,
};
#[derive(Clone)]
pub struct BaseTunables {
pub static_memory_bound: Pages,
pub static_memory_offset_guard_size: u64,
pub dynamic_memory_offset_guard_size: u64,
}
impl BaseTunables {
pub fn for_target(target: &Target) -> Self {
let triple = target.triple();
let pointer_width: PointerWidth = triple.pointer_width().unwrap();
let (static_memory_bound, static_memory_offset_guard_size): (Pages, u64) =
match pointer_width {
PointerWidth::U16 => (0x400.into(), 0x1000),
PointerWidth::U32 => (0x4000.into(), 0x1_0000),
PointerWidth::U64 => (0x1_0000.into(), 0x8000_0000),
};
#[cfg(target_os = "windows")]
let dynamic_memory_offset_guard_size: u64 = 0x2_0000;
#[cfg(not(target_os = "windows"))]
let dynamic_memory_offset_guard_size: u64 = 0x1_0000;
Self {
static_memory_bound,
static_memory_offset_guard_size,
dynamic_memory_offset_guard_size,
}
}
}
impl Tunables for BaseTunables {
fn memory_style(&self, memory: &MemoryType) -> MemoryStyle {
let maximum = memory.maximum.unwrap_or_else(Pages::max_value);
if maximum <= self.static_memory_bound {
MemoryStyle::Static {
bound: self.static_memory_bound,
offset_guard_size: self.static_memory_offset_guard_size,
}
} else {
MemoryStyle::Dynamic {
offset_guard_size: self.dynamic_memory_offset_guard_size,
}
}
}
fn table_style(&self, _table: &TableType) -> TableStyle {
TableStyle::CallerChecksSignature
}
fn create_host_memory(
&self,
ty: &MemoryType,
style: &MemoryStyle,
) -> Result<VMMemory, MemoryError> {
VMMemory::new(ty, style)
}
unsafe fn create_vm_memory(
&self,
ty: &MemoryType,
style: &MemoryStyle,
vm_definition_location: NonNull<VMMemoryDefinition>,
) -> Result<VMMemory, MemoryError> {
VMMemory::from_definition(ty, style, vm_definition_location)
}
fn create_host_table(&self, ty: &TableType, style: &TableStyle) -> Result<VMTable, String> {
VMTable::new(ty, style)
}
unsafe fn create_vm_table(
&self,
ty: &TableType,
style: &TableStyle,
vm_definition_location: NonNull<VMTableDefinition>,
) -> Result<VMTable, String> {
VMTable::from_definition(ty, style, vm_definition_location)
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn memory_style() {
let tunables = BaseTunables {
static_memory_bound: Pages(2048),
static_memory_offset_guard_size: 128,
dynamic_memory_offset_guard_size: 256,
};
let requested = MemoryType::new(3, None, true);
let style = tunables.memory_style(&requested);
match style {
MemoryStyle::Dynamic { offset_guard_size } => assert_eq!(offset_guard_size, 256),
s => panic!("Unexpected memory style: {:?}", s),
}
let requested = MemoryType::new(3, Some(5_000_000), true);
let style = tunables.memory_style(&requested);
match style {
MemoryStyle::Dynamic { offset_guard_size } => assert_eq!(offset_guard_size, 256),
s => panic!("Unexpected memory style: {:?}", s),
}
let requested = MemoryType::new(3, Some(16), true);
let style = tunables.memory_style(&requested);
match style {
MemoryStyle::Static {
bound,
offset_guard_size,
} => {
assert_eq!(bound, Pages(2048));
assert_eq!(offset_guard_size, 128);
}
s => panic!("Unexpected memory style: {:?}", s),
}
}
use std::cell::UnsafeCell;
use std::ptr::NonNull;
use wasmer_types::{MemoryError, MemoryStyle, MemoryType, Pages, WASM_PAGE_SIZE};
use wasmer_vm::LinearMemory;
#[derive(Debug)]
struct VMTinyMemory {
mem: Vec<u8>,
memory_definition: Option<UnsafeCell<VMMemoryDefinition>>,
}
unsafe impl Send for VMTinyMemory {}
unsafe impl Sync for VMTinyMemory {}
impl VMTinyMemory {
pub fn new() -> Result<Self, MemoryError> {
let sz = 18 * WASM_PAGE_SIZE;
let mut memory = Vec::new();
memory.resize(sz, 0);
let mut ret = VMTinyMemory {
mem: memory,
memory_definition: None,
};
ret.memory_definition = Some(UnsafeCell::new(VMMemoryDefinition {
base: ret.mem.as_ptr() as _,
current_length: sz,
}));
Ok(ret)
}
}
impl LinearMemory for VMTinyMemory {
fn ty(&self) -> MemoryType {
MemoryType {
minimum: Pages::from(18u32),
maximum: Some(Pages::from(18u32)),
shared: false,
}
}
fn size(&self) -> Pages {
Pages::from(18u32)
}
fn style(&self) -> MemoryStyle {
MemoryStyle::Static {
bound: Pages::from(18u32),
offset_guard_size: 0,
}
}
fn grow(&mut self, delta: Pages) -> Result<Pages, MemoryError> {
Err(MemoryError::CouldNotGrow {
current: Pages::from(100u32),
attempted_delta: delta,
})
}
fn vmmemory(&self) -> NonNull<VMMemoryDefinition> {
unsafe {
NonNull::new(
self.memory_definition
.as_ref()
.unwrap()
.get()
.as_mut()
.unwrap() as _,
)
.unwrap()
}
}
fn try_clone(&self) -> Option<Box<dyn LinearMemory + 'static>> {
None
}
}
impl From<VMTinyMemory> for wasmer_vm::VMMemory {
fn from(mem: VMTinyMemory) -> Self {
Self(Box::new(mem))
}
}
struct TinyTunables;
impl Tunables for TinyTunables {
fn memory_style(&self, _memory: &MemoryType) -> MemoryStyle {
MemoryStyle::Static {
bound: Pages::from(18u32),
offset_guard_size: 0,
}
}
fn table_style(&self, _table: &TableType) -> TableStyle {
TableStyle::CallerChecksSignature
}
fn create_host_memory(
&self,
_ty: &MemoryType,
_style: &MemoryStyle,
) -> Result<VMMemory, MemoryError> {
let memory = VMTinyMemory::new().unwrap();
Ok(VMMemory::from_custom(memory))
}
unsafe fn create_vm_memory(
&self,
_ty: &MemoryType,
_style: &MemoryStyle,
vm_definition_location: NonNull<VMMemoryDefinition>,
) -> Result<VMMemory, MemoryError> {
let memory = VMTinyMemory::new().unwrap();
let mut ptr = vm_definition_location;
let md = ptr.as_mut();
let unsafecell = memory.memory_definition.as_ref().unwrap();
let def = unsafecell.get().as_ref().unwrap();
md.base = def.base;
md.current_length = def.current_length;
Ok(memory.into())
}
fn create_host_table(&self, ty: &TableType, style: &TableStyle) -> Result<VMTable, String> {
VMTable::new(ty, style)
}
unsafe fn create_vm_table(
&self,
ty: &TableType,
style: &TableStyle,
vm_definition_location: NonNull<VMTableDefinition>,
) -> Result<VMTable, String> {
VMTable::from_definition(ty, style, vm_definition_location)
}
}
#[test]
fn check_linearmemory() {
let tunables = TinyTunables {};
let vmmemory = tunables.create_host_memory(
&MemoryType::new(1u32, Some(100u32), true),
&MemoryStyle::Static {
bound: Pages::from(18u32),
offset_guard_size: 0u64,
},
);
let mut vmmemory = vmmemory.unwrap();
assert!(vmmemory.grow(Pages::from(50u32)).is_err());
assert_eq!(vmmemory.size(), Pages::from(18u32));
assert_eq!(
vmmemory.grow(Pages::from(0u32)).err().unwrap(),
MemoryError::CouldNotGrow {
current: Pages::from(100u32),
attempted_delta: Pages::from(0u32)
}
);
}
#[test]
fn check_customtunables() -> Result<(), Box<dyn std::error::Error>> {
use crate::{imports, wat2wasm, Instance, Memory, Module, Store};
use wasmer_compiler_cranelift::Cranelift;
let wasm_bytes = wat2wasm(
br#"(module
(memory (;0;) 18)
(global (;0;) (mut i32) i32.const 1048576)
(export "memory" (memory 0))
(data (;0;) (i32.const 1048576) "*\00\00\00")
)"#,
)?;
let compiler = Cranelift::default();
let tunables = TinyTunables {};
let mut store = Store::new_with_tunables(compiler, tunables);
let module = Module::new(&store, wasm_bytes)?;
let import_object = imports! {};
let instance = Instance::new(&mut store, &module, &import_object)?;
let mut memories: Vec<Memory> = instance
.exports
.iter()
.memories()
.map(|pair| pair.1.clone())
.collect();
assert_eq!(memories.len(), 1);
let first_memory = memories.pop().unwrap();
assert_eq!(first_memory.ty(&store).maximum.unwrap(), Pages(18));
let view = first_memory.view(&store);
let x = unsafe { view.data_unchecked_mut() }[0];
assert_eq!(x, 0);
Ok(())
}
}