Files
wasmtime/lib/wasm/src/environ/dummy.rs

410 lines
13 KiB
Rust

//! "Dummy" environment for testing wasm translation.
use cretonne_codegen::cursor::FuncCursor;
use cretonne_codegen::ir::types::*;
use cretonne_codegen::ir::{self, InstBuilder};
use cretonne_codegen::settings;
use environ::{FuncEnvironment, GlobalValue, ModuleEnvironment, WasmResult};
use func_translator::FuncTranslator;
use std::string::String;
use std::vec::Vec;
use target_lexicon::Triple;
use translation_utils::{
FunctionIndex, Global, GlobalIndex, Memory, MemoryIndex, SignatureIndex, Table, TableIndex,
};
use wasmparser;
/// Compute a `ir::ExternalName` for a given wasm function index.
fn get_func_name(func_index: FunctionIndex) -> ir::ExternalName {
ir::ExternalName::user(0, func_index as u32)
}
/// A collection of names under which a given entity is exported.
pub struct Exportable<T> {
/// A wasm entity.
pub entity: T,
/// Names under which the entity is exported.
pub export_names: Vec<String>,
}
impl<T> Exportable<T> {
pub fn new(entity: T) -> Self {
Self {
entity,
export_names: Vec::new(),
}
}
}
/// The main state belonging to a `DummyEnvironment`. This is split out from
/// `DummyEnvironment` to allow it to be borrowed separately from the
/// `FuncTranslator` field.
pub struct DummyModuleInfo {
/// Target description.
pub triple: Triple,
/// Compilation setting flags.
pub flags: settings::Flags,
/// Signatures as provided by `declare_signature`.
pub signatures: Vec<ir::Signature>,
/// Module and field names of imported functions as provided by `declare_func_import`.
pub imported_funcs: Vec<(String, String)>,
/// Functions, imported and local.
pub functions: Vec<Exportable<SignatureIndex>>,
/// Function bodies.
pub function_bodies: Vec<ir::Function>,
/// Tables as provided by `declare_table`.
pub tables: Vec<Exportable<Table>>,
/// Memories as provided by `declare_memory`.
pub memories: Vec<Exportable<Memory>>,
/// Globals as provided by `declare_global`.
pub globals: Vec<Exportable<Global>>,
/// The start function.
pub start_func: Option<FunctionIndex>,
}
impl DummyModuleInfo {
/// Allocates the data structures with the given flags.
pub fn with_triple_flags(triple: Triple, flags: settings::Flags) -> Self {
Self {
triple,
flags,
signatures: Vec::new(),
imported_funcs: Vec::new(),
functions: Vec::new(),
function_bodies: Vec::new(),
tables: Vec::new(),
memories: Vec::new(),
globals: Vec::new(),
start_func: None,
}
}
}
/// This `ModuleEnvironment` implementation is a "naïve" one, doing essentially nothing and
/// emitting placeholders when forced to. Don't try to execute code translated for this
/// environment, essentially here for translation debug purposes.
pub struct DummyEnvironment {
/// Module information.
pub info: DummyModuleInfo,
/// Function translation.
trans: FuncTranslator,
/// Vector of wasm bytecode size for each function.
pub func_bytecode_sizes: Vec<usize>,
}
impl DummyEnvironment {
/// Allocates the data structures with default flags.
pub fn with_triple(triple: Triple) -> Self {
Self::with_triple_flags(triple, settings::Flags::new(settings::builder()))
}
/// Allocates the data structures with the given flags.
pub fn with_triple_flags(triple: Triple, flags: settings::Flags) -> Self {
Self {
info: DummyModuleInfo::with_triple_flags(triple, flags),
trans: FuncTranslator::new(),
func_bytecode_sizes: Vec::new(),
}
}
/// Return a `DummyFuncEnvironment` for translating functions within this
/// `DummyEnvironment`.
pub fn func_env(&self) -> DummyFuncEnvironment {
DummyFuncEnvironment::new(&self.info)
}
}
/// The `FuncEnvironment` implementation for use by the `DummyEnvironment`.
pub struct DummyFuncEnvironment<'dummy_environment> {
pub mod_info: &'dummy_environment DummyModuleInfo,
}
impl<'dummy_environment> DummyFuncEnvironment<'dummy_environment> {
pub fn new(mod_info: &'dummy_environment DummyModuleInfo) -> Self {
Self { mod_info }
}
// Create a signature for `sigidx` amended with a `vmctx` argument after the standard wasm
// arguments.
fn vmctx_sig(&self, sigidx: SignatureIndex) -> ir::Signature {
let mut sig = self.mod_info.signatures[sigidx].clone();
sig.params.push(ir::AbiParam::special(
self.native_pointer(),
ir::ArgumentPurpose::VMContext,
));
sig
}
}
impl<'dummy_environment> FuncEnvironment for DummyFuncEnvironment<'dummy_environment> {
fn triple(&self) -> &Triple {
&self.mod_info.triple
}
fn flags(&self) -> &settings::Flags {
&self.mod_info.flags
}
fn make_global(&mut self, func: &mut ir::Function, index: GlobalIndex) -> GlobalValue {
// Just create a dummy `vmctx` global.
let offset = ((index * 8) as i32 + 8).into();
let gv = func.create_global_value(ir::GlobalValueData::VMContext { offset });
GlobalValue::Memory {
gv,
ty: self.mod_info.globals[index].entity.ty,
}
}
fn make_heap(&mut self, func: &mut ir::Function, _index: MemoryIndex) -> ir::Heap {
// Create a static heap whose base address is stored at `vmctx+0`.
let gv = func.create_global_value(ir::GlobalValueData::VMContext { offset: 0.into() });
func.create_heap(ir::HeapData {
base: ir::HeapBase::GlobalValue(gv),
min_size: 0.into(),
guard_size: 0x8000_0000.into(),
style: ir::HeapStyle::Static {
bound: 0x1_0000_0000.into(),
},
})
}
fn make_indirect_sig(&mut self, func: &mut ir::Function, index: SignatureIndex) -> ir::SigRef {
// A real implementation would probably change the calling convention and add `vmctx` and
// signature index arguments.
func.import_signature(self.vmctx_sig(index))
}
fn make_direct_func(&mut self, func: &mut ir::Function, index: FunctionIndex) -> ir::FuncRef {
let sigidx = self.mod_info.functions[index].entity;
// A real implementation would probably add a `vmctx` argument.
// And maybe attempt some signature de-duplication.
let signature = func.import_signature(self.vmctx_sig(sigidx));
let name = get_func_name(index);
func.import_function(ir::ExtFuncData {
name,
signature,
colocated: false,
})
}
fn translate_call_indirect(
&mut self,
mut pos: FuncCursor,
_table_index: TableIndex,
_sig_index: SignatureIndex,
sig_ref: ir::SigRef,
callee: ir::Value,
call_args: &[ir::Value],
) -> WasmResult<ir::Inst> {
// Pass the current function's vmctx parameter on to the callee.
let vmctx = pos.func
.special_param(ir::ArgumentPurpose::VMContext)
.expect("Missing vmctx parameter");
// The `callee` value is an index into a table of function pointers.
// Apparently, that table is stored at absolute address 0 in this dummy environment.
// TODO: Generate bounds checking code.
let ptr = self.native_pointer();
let callee_offset = if ptr == I32 {
pos.ins().imul_imm(callee, 4)
} else {
let ext = pos.ins().uextend(I64, callee);
pos.ins().imul_imm(ext, 4)
};
let mut mflags = ir::MemFlags::new();
mflags.set_notrap();
mflags.set_aligned();
let func_ptr = pos.ins().load(ptr, mflags, callee_offset, 0);
// Build a value list for the indirect call instruction containing the callee, call_args,
// and the vmctx parameter.
let mut args = ir::ValueList::default();
args.push(func_ptr, &mut pos.func.dfg.value_lists);
args.extend(call_args.iter().cloned(), &mut pos.func.dfg.value_lists);
args.push(vmctx, &mut pos.func.dfg.value_lists);
Ok(pos.ins()
.CallIndirect(ir::Opcode::CallIndirect, VOID, sig_ref, args)
.0)
}
fn translate_call(
&mut self,
mut pos: FuncCursor,
_callee_index: FunctionIndex,
callee: ir::FuncRef,
call_args: &[ir::Value],
) -> WasmResult<ir::Inst> {
// Pass the current function's vmctx parameter on to the callee.
let vmctx = pos.func
.special_param(ir::ArgumentPurpose::VMContext)
.expect("Missing vmctx parameter");
// Build a value list for the call instruction containing the call_args and the vmctx
// parameter.
let mut args = ir::ValueList::default();
args.extend(call_args.iter().cloned(), &mut pos.func.dfg.value_lists);
args.push(vmctx, &mut pos.func.dfg.value_lists);
Ok(pos.ins().Call(ir::Opcode::Call, VOID, callee, args).0)
}
fn translate_memory_grow(
&mut self,
mut pos: FuncCursor,
_index: MemoryIndex,
_heap: ir::Heap,
_val: ir::Value,
) -> WasmResult<ir::Value> {
Ok(pos.ins().iconst(I32, -1))
}
fn translate_memory_size(
&mut self,
mut pos: FuncCursor,
_index: MemoryIndex,
_heap: ir::Heap,
) -> WasmResult<ir::Value> {
Ok(pos.ins().iconst(I32, -1))
}
}
impl<'data> ModuleEnvironment<'data> for DummyEnvironment {
fn flags(&self) -> &settings::Flags {
&self.info.flags
}
fn get_func_name(&self, func_index: FunctionIndex) -> ir::ExternalName {
get_func_name(func_index)
}
fn declare_signature(&mut self, sig: &ir::Signature) {
self.info.signatures.push(sig.clone());
}
fn get_signature(&self, sig_index: SignatureIndex) -> &ir::Signature {
&self.info.signatures[sig_index]
}
fn declare_func_import(
&mut self,
sig_index: SignatureIndex,
module: &'data str,
field: &'data str,
) {
assert_eq!(
self.info.functions.len(),
self.info.imported_funcs.len(),
"Imported functions must be declared first"
);
self.info.functions.push(Exportable::new(sig_index));
self.info
.imported_funcs
.push((String::from(module), String::from(field)));
}
fn get_num_func_imports(&self) -> usize {
self.info.imported_funcs.len()
}
fn declare_func_type(&mut self, sig_index: SignatureIndex) {
self.info.functions.push(Exportable::new(sig_index));
}
fn get_func_type(&self, func_index: FunctionIndex) -> SignatureIndex {
self.info.functions[func_index].entity
}
fn declare_global(&mut self, global: Global) {
self.info.globals.push(Exportable::new(global));
}
fn get_global(&self, global_index: GlobalIndex) -> &Global {
&self.info.globals[global_index].entity
}
fn declare_table(&mut self, table: Table) {
self.info.tables.push(Exportable::new(table));
}
fn declare_table_elements(
&mut self,
_table_index: TableIndex,
_base: Option<GlobalIndex>,
_offset: usize,
_elements: Vec<FunctionIndex>,
) {
// We do nothing
}
fn declare_memory(&mut self, memory: Memory) {
self.info.memories.push(Exportable::new(memory));
}
fn declare_data_initialization(
&mut self,
_memory_index: MemoryIndex,
_base: Option<GlobalIndex>,
_offset: usize,
_data: &'data [u8],
) {
// We do nothing
}
fn declare_func_export(&mut self, func_index: FunctionIndex, name: &'data str) {
self.info.functions[func_index]
.export_names
.push(String::from(name));
}
fn declare_table_export(&mut self, table_index: TableIndex, name: &'data str) {
self.info.tables[table_index]
.export_names
.push(String::from(name));
}
fn declare_memory_export(&mut self, memory_index: MemoryIndex, name: &'data str) {
self.info.memories[memory_index]
.export_names
.push(String::from(name));
}
fn declare_global_export(&mut self, global_index: GlobalIndex, name: &'data str) {
self.info.globals[global_index]
.export_names
.push(String::from(name));
}
fn declare_start_func(&mut self, func_index: FunctionIndex) {
debug_assert!(self.info.start_func.is_none());
self.info.start_func = Some(func_index);
}
fn define_function_body(&mut self, body_bytes: &'data [u8]) -> WasmResult<()> {
let func = {
let mut func_environ = DummyFuncEnvironment::new(&self.info);
let function_index = self.get_num_func_imports() + self.info.function_bodies.len();
let name = get_func_name(function_index);
let sig = func_environ.vmctx_sig(self.get_func_type(function_index));
let mut func = ir::Function::with_name_signature(name, sig);
let reader = wasmparser::BinaryReader::new(body_bytes);
self.trans
.translate_from_reader(reader, &mut func, &mut func_environ)?;
func
};
self.func_bytecode_sizes.push(body_bytes.len());
self.info.function_bodies.push(func);
Ok(())
}
}