Files
wasmer/lib/compiler-llvm/src/trampoline/wasm.rs

430 lines
14 KiB
Rust

use crate::config::{CompiledFunctionKind, LLVMConfig};
use crate::object_file::load_object_file;
use crate::translator::abi::{func_type_to_llvm, rets_from_call};
use crate::translator::intrinsics::{type_to_llvm, type_to_llvm_ptr, Intrinsics};
use inkwell::{
attributes::{Attribute, AttributeLoc},
context::Context,
module::Linkage,
passes::PassManager,
targets::FileType,
types::BasicType,
values::{BasicValue, FunctionValue},
AddressSpace,
};
use std::cmp;
use std::convert::TryInto;
use std::iter;
use wasm_common::{FunctionType, Type};
use wasmer_compiler::{CompileError, FunctionBody};
pub struct FuncTrampoline {
ctx: Context,
}
const FUNCTION_SECTION: &str = ".wasmer_trampoline";
impl FuncTrampoline {
pub fn new() -> Self {
Self {
ctx: Context::create(),
}
}
pub fn trampoline(
&mut self,
ty: &FunctionType,
config: &LLVMConfig,
) -> Result<FunctionBody, CompileError> {
// The function type, used for the callbacks.
let function = CompiledFunctionKind::FunctionCallTrampoline(ty.clone());
let module = self.ctx.create_module("");
let target_triple = config.target_triple();
let target_machine = config.target_machine();
module.set_triple(&target_triple);
module.set_data_layout(&target_machine.get_target_data().get_data_layout());
let intrinsics = Intrinsics::declare(&module, &self.ctx);
let (callee_ty, callee_attrs) = func_type_to_llvm(&self.ctx, &intrinsics, ty)?;
let trampoline_ty = intrinsics.void_ty.fn_type(
&[
intrinsics.ctx_ptr_ty.as_basic_type_enum(), // callee_vmctx ptr
callee_ty
.ptr_type(AddressSpace::Generic)
.as_basic_type_enum(), // callee function address
intrinsics.i128_ptr_ty.as_basic_type_enum(), // in/out values ptr
],
false,
);
let trampoline_func = module.add_function("", trampoline_ty, Some(Linkage::External));
trampoline_func
.as_global_value()
.set_section(FUNCTION_SECTION);
generate_trampoline(trampoline_func, ty, &callee_attrs, &self.ctx, &intrinsics)?;
if let Some(ref callbacks) = config.callbacks {
callbacks.preopt_ir(&function, &module);
}
let pass_manager = PassManager::create(());
if config.enable_verifier {
pass_manager.add_verifier_pass();
}
pass_manager.add_early_cse_pass();
pass_manager.run_on(&module);
if let Some(ref callbacks) = config.callbacks {
callbacks.postopt_ir(&function, &module);
}
let memory_buffer = target_machine
.write_to_memory_buffer(&module, FileType::Object)
.unwrap();
if let Some(ref callbacks) = config.callbacks {
callbacks.obj_memory_buffer(&function, &memory_buffer);
}
let mem_buf_slice = memory_buffer.as_slice();
let (function, sections) =
load_object_file(mem_buf_slice, FUNCTION_SECTION, None, |name: &String| {
Err(CompileError::Codegen(format!(
"trampoline generation produced reference to unknown function {}",
name
)))
})?;
if !sections.is_empty() {
return Err(CompileError::Codegen(
"trampoline generation produced custom sections".into(),
));
}
if !function.relocations.is_empty() {
return Err(CompileError::Codegen(
"trampoline generation produced relocations".into(),
));
}
if !function.jt_offsets.is_empty() {
return Err(CompileError::Codegen(
"trampoline generation produced jump tables".into(),
));
}
// Ignore CompiledFunctionFrameInfo. Extra frame info isn't a problem.
Ok(FunctionBody {
body: function.body.body,
unwind_info: function.body.unwind_info,
})
}
pub fn dynamic_trampoline(
&mut self,
ty: &FunctionType,
config: &LLVMConfig,
) -> Result<FunctionBody, CompileError> {
// The function type, used for the callbacks
let function = CompiledFunctionKind::DynamicFunctionTrampoline(ty.clone());
let module = self.ctx.create_module("");
let target_triple = config.target_triple();
let target_machine = config.target_machine();
module.set_triple(&target_triple);
module.set_data_layout(&target_machine.get_target_data().get_data_layout());
let intrinsics = Intrinsics::declare(&module, &self.ctx);
let params = iter::once(Ok(intrinsics.ctx_ptr_ty.as_basic_type_enum()))
.chain(
ty.params()
.iter()
.map(|param_ty| type_to_llvm(&intrinsics, *param_ty)),
)
.collect::<Result<Vec<_>, _>>()?;
let trampoline_ty = intrinsics.void_ty.fn_type(params.as_slice(), false);
let trampoline_func = module.add_function("", trampoline_ty, Some(Linkage::External));
trampoline_func
.as_global_value()
.set_section(FUNCTION_SECTION);
generate_dynamic_trampoline(trampoline_func, ty, &self.ctx, &intrinsics)?;
if let Some(ref callbacks) = config.callbacks {
callbacks.preopt_ir(&function, &module);
}
let pass_manager = PassManager::create(());
if config.enable_verifier {
pass_manager.add_verifier_pass();
}
pass_manager.add_early_cse_pass();
pass_manager.run_on(&module);
if let Some(ref callbacks) = config.callbacks {
callbacks.postopt_ir(&function, &module);
}
let memory_buffer = target_machine
.write_to_memory_buffer(&module, FileType::Object)
.unwrap();
if let Some(ref callbacks) = config.callbacks {
callbacks.obj_memory_buffer(&function, &memory_buffer);
}
let mem_buf_slice = memory_buffer.as_slice();
let (function, sections) =
load_object_file(mem_buf_slice, FUNCTION_SECTION, None, |name: &String| {
Err(CompileError::Codegen(format!(
"trampoline generation produced reference to unknown function {}",
name
)))
})?;
if !sections.is_empty() {
return Err(CompileError::Codegen(
"trampoline generation produced custom sections".into(),
));
}
if !function.relocations.is_empty() {
return Err(CompileError::Codegen(
"trampoline generation produced relocations".into(),
));
}
if !function.jt_offsets.is_empty() {
return Err(CompileError::Codegen(
"trampoline generation produced jump tables".into(),
));
}
// Ignore CompiledFunctionFrameInfo. Extra frame info isn't a problem.
Ok(FunctionBody {
body: function.body.body,
unwind_info: function.body.unwind_info,
})
}
}
fn generate_trampoline<'ctx>(
trampoline_func: FunctionValue,
func_sig: &FunctionType,
func_attrs: &[(Attribute, AttributeLoc)],
context: &'ctx Context,
intrinsics: &Intrinsics<'ctx>,
) -> Result<(), CompileError> {
let entry_block = context.append_basic_block(trampoline_func, "entry");
let builder = context.create_builder();
builder.position_at_end(entry_block);
/*
// TODO: remove debugging
builder.build_call(
intrinsics.debug_trap,
&[],
"");
*/
let (callee_vmctx_ptr, func_ptr, args_rets_ptr) = match *trampoline_func.get_params().as_slice()
{
[callee_vmctx_ptr, func_ptr, args_rets_ptr] => (
callee_vmctx_ptr,
func_ptr.into_pointer_value(),
args_rets_ptr.into_pointer_value(),
),
_ => {
return Err(CompileError::Codegen(
"trampoline function unimplemented".to_string(),
))
}
};
let mut args_vec = Vec::with_capacity(func_sig.params().len() + 1);
let func_sig_returns_bitwidths = func_sig
.results()
.iter()
.map(|ty| match ty {
Type::I32 | Type::F32 => Ok(32),
Type::I64 | Type::F64 => Ok(64),
Type::V128 => Ok(128),
ty => {
return Err(CompileError::Codegen(format!(
"generate_trampoline: unimplemented wasm_common type {:?}",
ty
)))
}
})
.collect::<Result<Vec<i32>, _>>()?;
let _is_sret = match func_sig_returns_bitwidths.as_slice() {
[]
| [_]
| [32, 64]
| [64, 32]
| [64, 64]
| [32, 32]
| [32, 32, 32]
| [32, 32, 64]
| [64, 32, 32]
| [32, 32, 32, 32] => false,
_ => {
let basic_types: Vec<_> = func_sig
.results()
.iter()
.map(|&ty| type_to_llvm(intrinsics, ty))
.collect::<Result<_, _>>()?;
let sret_ty = context.struct_type(&basic_types, false);
args_vec.push(builder.build_alloca(sret_ty, "sret").into());
true
}
};
args_vec.push(callee_vmctx_ptr);
let mut i = 0;
for param_ty in func_sig.params().iter() {
let index = intrinsics.i32_ty.const_int(i as _, false);
let item_pointer =
unsafe { builder.build_in_bounds_gep(args_rets_ptr, &[index], "arg_ptr") };
let casted_pointer_type = type_to_llvm_ptr(intrinsics, *param_ty)?;
let typed_item_pointer =
builder.build_pointer_cast(item_pointer, casted_pointer_type, "typed_arg_pointer");
let arg = builder.build_load(typed_item_pointer, "arg");
args_vec.push(arg);
i += 1;
if *param_ty == Type::V128 {
i += 1;
}
}
let call_site = builder.build_call(func_ptr, &args_vec, "call");
for (attr, attr_loc) in func_attrs {
call_site.add_attribute(*attr_loc, *attr);
}
let rets = rets_from_call(&builder, intrinsics, call_site, func_sig);
let mut idx = 0;
rets.iter().for_each(|v| {
let ptr = unsafe {
builder.build_gep(
args_rets_ptr,
&[intrinsics.i32_ty.const_int(idx, false)],
"",
)
};
let ptr = builder.build_pointer_cast(ptr, v.get_type().ptr_type(AddressSpace::Generic), "");
builder.build_store(ptr, *v);
if v.get_type() == intrinsics.i128_ty.as_basic_type_enum() {
idx += 1;
}
idx += 1;
});
builder.build_return(None);
Ok(())
}
fn generate_dynamic_trampoline<'ctx>(
trampoline_func: FunctionValue,
func_sig: &FunctionType,
context: &'ctx Context,
intrinsics: &Intrinsics<'ctx>,
) -> Result<(), CompileError> {
let entry_block = context.append_basic_block(trampoline_func, "entry");
let builder = context.create_builder();
builder.position_at_end(entry_block);
/*
// TODO: remove debugging
builder.build_call(
intrinsics.debug_trap,
&[],
"");
*/
// Allocate stack space for the params and results.
let values = builder.build_alloca(
intrinsics.i128_ty.array_type(cmp::max(
func_sig.params().len().try_into().unwrap(),
func_sig.results().len().try_into().unwrap(),
)),
"",
);
// Copy params to 'values'.
for i in 0..func_sig.params().len() {
let ptr = unsafe {
builder.build_in_bounds_gep(
values,
&[
intrinsics.i32_zero,
intrinsics.i32_ty.const_int(i.try_into().unwrap(), false),
],
"",
)
};
let ptr = builder
.build_bitcast(ptr, type_to_llvm_ptr(intrinsics, func_sig.params()[i])?, "")
.into_pointer_value();
builder.build_store(ptr, trampoline_func.get_nth_param(i as u32 + 1).unwrap());
}
let callee_ty = intrinsics
.void_ty
.fn_type(
&[
intrinsics.ctx_ptr_ty.as_basic_type_enum(),
intrinsics.i128_ptr_ty.as_basic_type_enum(),
],
false,
)
.ptr_type(AddressSpace::Generic)
.ptr_type(AddressSpace::Generic);
let vmctx = trampoline_func.get_nth_param(0).unwrap();
let callee = builder
.build_load(
builder
.build_bitcast(vmctx, callee_ty, "")
.into_pointer_value(),
"",
)
.into_pointer_value();
builder.build_call(
callee,
&[vmctx.as_basic_value_enum(), values.as_basic_value_enum()],
"",
);
match func_sig.results() {
[] => {
builder.build_return(None);
}
[ty] => {
let ptr = unsafe {
builder.build_in_bounds_gep(
values,
&[intrinsics.i32_zero, intrinsics.i32_ty.const_int(0, false)],
"",
)
};
let ptr = builder
.build_bitcast(ptr, type_to_llvm_ptr(intrinsics, *ty)?, "")
.into_pointer_value();
let ret = builder.build_load(ptr, "");
builder.build_return(Some(&ret));
}
_ => unimplemented!("multi-value return is not yet implemented"),
};
Ok(())
}