Files
wasmer/lib/compiler-llvm/src/trampoline/wasm.rs
2020-06-20 13:43:46 -07:00

476 lines
16 KiB
Rust

use crate::config::{CompiledFunctionKind, LLVM};
use crate::object_file::{load_object_file, CompiledFunction};
use crate::translator::abi::{
func_type_to_llvm, get_vmctx_ptr_param, is_sret, pack_values_for_register_return,
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, TargetMachine},
types::BasicType,
values::{BasicValue, FunctionValue},
AddressSpace,
};
use std::cmp;
use std::convert::TryInto;
use wasm_common::{FunctionType, LocalFunctionIndex, Type};
use wasmer_compiler::{CompileError, FunctionBody, RelocationTarget};
pub struct FuncTrampoline {
ctx: Context,
target_machine: TargetMachine,
}
const FUNCTION_SECTION: &str = ".wasmer_trampoline";
impl FuncTrampoline {
pub fn new(target_machine: TargetMachine) -> Self {
Self {
ctx: Context::create(),
target_machine,
}
}
pub fn trampoline(
&mut self,
ty: &FunctionType,
config: &LLVM,
) -> Result<FunctionBody, CompileError> {
// The function type, used for the callbacks.
let function = CompiledFunctionKind::FunctionCallTrampoline(ty.clone());
let module = self.ctx.create_module("");
let target_machine = &self.target_machine;
let target_triple = target_machine.get_triple();
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(), // 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 CompiledFunction {
compiled_function,
custom_sections,
eh_frame_section_indices,
} = load_object_file(
mem_buf_slice,
FUNCTION_SECTION,
RelocationTarget::LocalFunc(LocalFunctionIndex::from_u32(0)),
|name: &String| {
Err(CompileError::Codegen(format!(
"trampoline generation produced reference to unknown function {}",
name
)))
},
)?;
let mut all_sections_are_eh_sections = true;
if eh_frame_section_indices.len() != custom_sections.len() {
all_sections_are_eh_sections = false;
} else {
let mut eh_frame_section_indices = eh_frame_section_indices;
eh_frame_section_indices.sort_unstable();
for (idx, section_idx) in eh_frame_section_indices.iter().enumerate() {
if idx as u32 != section_idx.as_u32() {
all_sections_are_eh_sections = false;
break;
}
}
}
if !all_sections_are_eh_sections {
return Err(CompileError::Codegen(
"trampoline generation produced non-eh custom sections".into(),
));
}
if !compiled_function.relocations.is_empty() {
return Err(CompileError::Codegen(
"trampoline generation produced relocations".into(),
));
}
if !compiled_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: compiled_function.body.body,
unwind_info: compiled_function.body.unwind_info,
})
}
pub fn dynamic_trampoline(
&mut self,
ty: &FunctionType,
config: &LLVM,
) -> Result<FunctionBody, CompileError> {
// The function type, used for the callbacks
let function = CompiledFunctionKind::DynamicFunctionTrampoline(ty.clone());
let module = self.ctx.create_module("");
let target_machine = &self.target_machine;
let target_triple = target_machine.get_triple();
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 (trampoline_ty, trampoline_attrs) = func_type_to_llvm(&self.ctx, &intrinsics, ty)?;
let trampoline_func = module.add_function("", trampoline_ty, Some(Linkage::External));
for (attr, attr_loc) in trampoline_attrs {
trampoline_func.add_attribute(attr_loc, attr);
}
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 CompiledFunction {
compiled_function,
custom_sections,
eh_frame_section_indices,
} = load_object_file(
mem_buf_slice,
FUNCTION_SECTION,
RelocationTarget::LocalFunc(LocalFunctionIndex::from_u32(0)),
|name: &String| {
Err(CompileError::Codegen(format!(
"trampoline generation produced reference to unknown function {}",
name
)))
},
)?;
let mut all_sections_are_eh_sections = true;
if eh_frame_section_indices.len() != custom_sections.len() {
all_sections_are_eh_sections = false;
} else {
let mut eh_frame_section_indices = eh_frame_section_indices;
eh_frame_section_indices.sort_unstable();
for (idx, section_idx) in eh_frame_section_indices.iter().enumerate() {
if idx as u32 != section_idx.as_u32() {
all_sections_are_eh_sections = false;
break;
}
}
}
if !all_sections_are_eh_sections {
return Err(CompileError::Codegen(
"trampoline generation produced non-eh custom sections".into(),
));
}
if !compiled_function.relocations.is_empty() {
return Err(CompileError::Codegen(
"trampoline generation produced relocations".into(),
));
}
if !compiled_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: compiled_function.body.body,
unwind_info: compiled_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);
if is_sret(func_sig)? {
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());
}
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);
// 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'.
let first_user_param = if is_sret(func_sig)? { 2 } else { 1 };
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 + first_user_param)
.unwrap(),
);
}
let callee_ty = intrinsics
.void_ty
.fn_type(
&[
intrinsics.ctx_ptr_ty.as_basic_type_enum(), // vmctx ptr
intrinsics.i128_ptr_ty.as_basic_type_enum(), // in/out values ptr
],
false,
)
.ptr_type(AddressSpace::Generic);
let vmctx = get_vmctx_ptr_param(&trampoline_func);
let callee = builder
.build_load(
builder
.build_bitcast(vmctx, callee_ty.ptr_type(AddressSpace::Generic), "")
.into_pointer_value(),
"",
)
.into_pointer_value();
let values_ptr = builder.build_pointer_cast(values, intrinsics.i128_ptr_ty, "");
builder.build_call(
callee,
&[
vmctx.as_basic_value_enum(),
values_ptr.as_basic_value_enum(),
],
"",
);
if func_sig.results().is_empty() {
builder.build_return(None);
} else {
let results = func_sig
.results()
.iter()
.enumerate()
.map(|(idx, ty)| {
let ptr = unsafe {
builder.build_gep(
values,
&[
intrinsics.i32_ty.const_zero(),
intrinsics.i32_ty.const_int(idx.try_into().unwrap(), false),
],
"",
)
};
let ptr = builder.build_pointer_cast(ptr, type_to_llvm_ptr(intrinsics, *ty)?, "");
Ok(builder.build_load(ptr, ""))
})
.collect::<Result<Vec<_>, CompileError>>()?;
if is_sret(func_sig)? {
let sret = trampoline_func
.get_first_param()
.unwrap()
.into_pointer_value();
let mut struct_value = sret
.get_type()
.get_element_type()
.into_struct_type()
.get_undef();
for (idx, value) in results.iter().enumerate() {
let value = builder.build_bitcast(
*value,
type_to_llvm(&intrinsics, func_sig.results()[idx])?,
"",
);
struct_value = builder
.build_insert_value(struct_value, value, idx as u32, "")
.unwrap()
.into_struct_value();
}
builder.build_store(sret, struct_value);
builder.build_return(None);
} else {
builder.build_return(Some(&pack_values_for_register_return(
&intrinsics,
&builder,
&results.as_slice(),
&trampoline_func.get_type(),
)?));
}
}
Ok(())
}