deno.land / x / deno@v1.28.2 / ext / ffi / fast_call.rs
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Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
use std::cmp::max;use std::ffi::c_void;use std::iter::once;
use deno_core::v8::fast_api;use dynasmrt::dynasm;use dynasmrt::DynasmApi;use dynasmrt::ExecutableBuffer;
use crate::needs_unwrap;use crate::NativeType;use crate::Symbol;
pub(crate) fn is_compatible(sym: &Symbol) -> bool { cfg!(any( all(target_arch = "x86_64", target_family = "unix"), all(target_arch = "x86_64", target_family = "windows"), all(target_arch = "aarch64", target_vendor = "apple") )) && !sym.can_callback}
pub(crate) fn compile_trampoline(sym: &Symbol) -> Trampoline { #[cfg(all(target_arch = "x86_64", target_family = "unix"))] return SysVAmd64::compile(sym); #[cfg(all(target_arch = "x86_64", target_family = "windows"))] return Win64::compile(sym); #[cfg(all(target_arch = "aarch64", target_vendor = "apple"))] return Aarch64Apple::compile(sym); #[allow(unreachable_code)] { unimplemented!("fast API is not implemented for the current target"); }}
pub(crate) fn make_template(sym: &Symbol, trampoline: &Trampoline) -> Template { let mut params = once(fast_api::Type::V8Value) // Receiver .chain(sym.parameter_types.iter().map(|t| t.into())) .collect::<Vec<_>>();
let ret = if needs_unwrap(sym.result_type) { params.push(fast_api::Type::TypedArray(fast_api::CType::Int32)); fast_api::Type::Void } else { fast_api::Type::from(&sym.result_type) };
Template { args: params.into_boxed_slice(), ret: (&ret).into(), symbol_ptr: trampoline.ptr(), }}
/// Trampoline for fast-call FFI functions////// Calls the FFI function without the first argument (the receiver)pub(crate) struct Trampoline(ExecutableBuffer);
impl Trampoline { fn ptr(&self) -> *const c_void { &self.0[0] as *const u8 as *const c_void }}
pub(crate) struct Template { args: Box<[fast_api::Type]>, ret: fast_api::CType, symbol_ptr: *const c_void,}
impl fast_api::FastFunction for Template { fn function(&self) -> *const c_void { self.symbol_ptr }
fn args(&self) -> &'static [fast_api::Type] { Box::leak(self.args.clone()) }
fn return_type(&self) -> fast_api::CType { self.ret }}
impl From<&NativeType> for fast_api::Type { fn from(native_type: &NativeType) -> Self { match native_type { NativeType::Bool => fast_api::Type::Bool, NativeType::U8 | NativeType::U16 | NativeType::U32 => { fast_api::Type::Uint32 } NativeType::I8 | NativeType::I16 | NativeType::I32 => { fast_api::Type::Int32 } NativeType::F32 => fast_api::Type::Float32, NativeType::F64 => fast_api::Type::Float64, NativeType::Void => fast_api::Type::Void, NativeType::I64 => fast_api::Type::Int64, NativeType::U64 => fast_api::Type::Uint64, NativeType::ISize => fast_api::Type::Int64, NativeType::USize | NativeType::Pointer | NativeType::Function => { fast_api::Type::Uint64 } NativeType::Buffer => fast_api::Type::TypedArray(fast_api::CType::Uint8), } }}
macro_rules! x64 { ($assembler:expr; $($tokens:tt)+) => { dynasm!($assembler; .arch x64; $($tokens)+) }}
macro_rules! aarch64 { ($assembler:expr; $($tokens:tt)+) => { dynasm!($assembler; .arch aarch64; $($tokens)+) }}
struct SysVAmd64 { // Reference: https://refspecs.linuxfoundation.org/elf/x86_64-abi-0.99.pdf assmblr: dynasmrt::x64::Assembler, // Parameter counters integral_params: u32, float_params: u32, // Stack offset accumulators offset_trampoline: u32, offset_callee: u32, allocated_stack: u32, frame_pointer: u32,}
#[cfg_attr( not(all(target_aarch = "x86_64", target_family = "unix")), allow(dead_code))]impl SysVAmd64 { // Integral arguments go to the following GPR, in order: rdi, rsi, rdx, rcx, r8, r9 const INTEGRAL_REGISTERS: u32 = 6; // SSE arguments go to the first 8 SSE registers: xmm0-xmm7 const FLOAT_REGISTERS: u32 = 8;
fn new() -> Self { Self { assmblr: dynasmrt::x64::Assembler::new().unwrap(), integral_params: 0, float_params: 0, // Start at 8 to account for trampoline caller's return address offset_trampoline: 8, // default to tail-call mode. If a new stack frame is allocated this becomes 0 offset_callee: 8, allocated_stack: 0, frame_pointer: 0, } }
fn compile(sym: &Symbol) -> Trampoline { let mut compiler = Self::new();
let must_cast_return_value = compiler.must_cast_return_value(sym.result_type); let must_wrap_return_value = compiler.must_wrap_return_value_in_typed_array(sym.result_type); let must_save_preserved_register = must_wrap_return_value; let cannot_tailcall = must_cast_return_value || must_wrap_return_value;
if cannot_tailcall { if must_save_preserved_register { compiler.save_preserved_register_to_stack(); } compiler.allocate_stack(&sym.parameter_types); }
for param in sym.parameter_types.iter().copied() { compiler.move_left(param) } if !compiler.is_recv_arg_overridden() { // the receiver object should never be expected. Avoid its unexpected or deliberate leak compiler.zero_first_arg(); } if must_wrap_return_value { compiler.save_out_array_to_preserved_register(); }
if cannot_tailcall { compiler.call(sym.ptr.as_ptr()); if must_cast_return_value { compiler.cast_return_value(sym.result_type); } if must_wrap_return_value { compiler.wrap_return_value_in_out_array(); } compiler.deallocate_stack(); if must_save_preserved_register { compiler.recover_preserved_register(); } compiler.ret(); } else { compiler.tailcall(sym.ptr.as_ptr()); }
Trampoline(compiler.finalize()) }
fn move_left(&mut self, param: NativeType) { // Section 3.2.3 of the SysV ABI spec, on argument classification: // - INTEGER: // > Arguments of types (signed and unsigned) _Bool, char, short, int, // > long, long long, and pointers are in the INTEGER class. // - SSE: // > Arguments of types float, double, _Decimal32, _Decimal64 and // > __m64 are in class SSE. match param.into() { Int(integral) => self.move_integral(integral), Float(float) => self.move_float(float), } }
fn move_float(&mut self, param: Floating) { // Section 3.2.3 of the SysV AMD64 ABI: // > If the class is SSE, the next available vector register is used, the registers // > are taken in the order from %xmm0 to %xmm7. // [...] // > Once registers are assigned, the arguments passed in memory are pushed on // > the stack in reversed (right-to-left) order let param_i = self.float_params;
let is_in_stack = param_i >= Self::FLOAT_REGISTERS; // floats are only moved to accommodate integer movement in the stack let stack_has_moved = self.allocated_stack > 0 || self.integral_params >= Self::INTEGRAL_REGISTERS;
if is_in_stack && stack_has_moved { let s = &mut self.assmblr; let ot = self.offset_trampoline as i32; let oc = self.offset_callee as i32; match param { Single => x64!(s ; movss xmm8, [rsp + ot] ; movss [rsp + oc], xmm8 ), Double => x64!(s ; movsd xmm8, [rsp + ot] ; movsd [rsp + oc], xmm8 ), }
// Section 3.2.3 of the SysV AMD64 ABI: // > The size of each argument gets rounded up to eightbytes. [...] Therefore the stack will always be eightbyte aligned. self.offset_trampoline += 8; self.offset_callee += 8;
debug_assert!( self.allocated_stack == 0 || self.offset_callee <= self.allocated_stack ); } self.float_params += 1; }
fn move_integral(&mut self, arg: Integral) { // Section 3.2.3 of the SysV AMD64 ABI: // > If the class is INTEGER, the next available register of the sequence %rdi, // > %rsi, %rdx, %rcx, %r8 and %r9 is used // [...] // > Once registers are assigned, the arguments passed in memory are pushed on // > the stack in reversed (right-to-left) order let s = &mut self.assmblr; let param_i = self.integral_params;
// move each argument one position to the left. The first argument in the stack moves to the last integer register (r9). // If the FFI function is called with a new stack frame, the arguments remaining in the stack are copied to the new stack frame. // Otherwise, they are copied 8 bytes lower in the same frame match (param_i, arg) { // u8 and u16 parameters are defined as u32 parameters in the V8's fast API function. The trampoline takes care of the cast. // Conventionally, many compilers expect 8 and 16 bit arguments to be sign/zero extended by the caller // See https://stackoverflow.com/a/36760539/2623340 (0, U(B)) => x64!(s; movzx edi, sil), (0, I(B)) => x64!(s; movsx edi, sil), (0, U(W)) => x64!(s; movzx edi, si), (0, I(W)) => x64!(s; movsx edi, si), (0, U(DW) | I(DW)) => x64!(s; mov edi, esi), (0, U(QW) | I(QW)) => x64!(s; mov rdi, rsi), // The fast API expects buffer arguments passed as a pointer to a FastApiTypedArray<Uint8> struct // Here we blindly follow the layout of https://github.com/denoland/rusty_v8/blob/main/src/fast_api.rs#L190-L200 // although that might be problematic: https://discord.com/channels/684898665143206084/956626010248478720/1009450940866252823 (0, Buffer) => x64!(s; mov rdi, [rsi + 8]),
(1, U(B)) => x64!(s; movzx esi, dl), (1, I(B)) => x64!(s; movsx esi, dl), (1, U(W)) => x64!(s; movzx esi, dx), (1, I(W)) => x64!(s; movsx esi, dx), (1, U(DW) | I(DW)) => x64!(s; mov esi, edx), (1, U(QW) | I(QW)) => x64!(s; mov rsi, rdx), (1, Buffer) => x64!(s; mov rsi, [rdx + 8]),
(2, U(B)) => x64!(s; movzx edx, cl), (2, I(B)) => x64!(s; movsx edx, cl), (2, U(W)) => x64!(s; movzx edx, cx), (2, I(W)) => x64!(s; movsx edx, cx), (2, U(DW) | I(DW)) => x64!(s; mov edx, ecx), (2, U(QW) | I(QW)) => x64!(s; mov rdx, rcx), (2, Buffer) => x64!(s; mov rdx, [rcx + 8]),
(3, U(B)) => x64!(s; movzx ecx, r8b), (3, I(B)) => x64!(s; movsx ecx, r8b), (3, U(W)) => x64!(s; movzx ecx, r8w), (3, I(W)) => x64!(s; movsx ecx, r8w), (3, U(DW) | I(DW)) => x64!(s; mov ecx, r8d), (3, U(QW) | I(QW)) => x64!(s; mov rcx, r8), (3, Buffer) => x64!(s; mov rcx, [r8 + 8]),
(4, U(B)) => x64!(s; movzx r8d, r9b), (4, I(B)) => x64!(s; movsx r8d, r9b), (4, U(W)) => x64!(s; movzx r8d, r9w), (4, I(W)) => x64!(s; movsx r8d, r9w), (4, U(DW) | I(DW)) => x64!(s; mov r8d, r9d), (4, U(QW) | I(QW)) => x64!(s; mov r8, r9), (4, Buffer) => x64!(s; mov r8, [r9 + 8]),
(5, param) => { let ot = self.offset_trampoline as i32; // First argument in stack goes to last register (r9) match param { U(B) => x64!(s; movzx r9d, BYTE [rsp + ot]), I(B) => x64!(s; movsx r9d, BYTE [rsp + ot]), U(W) => x64!(s; movzx r9d, WORD [rsp + ot]), I(W) => x64!(s; movsx r9d, WORD [rsp + ot]), U(DW) | I(DW) => x64!(s; mov r9d, [rsp + ot]), U(QW) | I(QW) => x64!(s; mov r9, [rsp + ot]), Buffer => x64!(s ; mov r9, [rsp + ot] ; mov r9, [r9 + 8] ), } // Section 3.2.3 of the SysV AMD64 ABI: // > The size of each argument gets rounded up to eightbytes. [...] Therefore the stack will always be eightbyte aligned. self.offset_trampoline += 8; }
(6.., param) => { let ot = self.offset_trampoline as i32; let oc = self.offset_callee as i32; match param { U(B) => x64!(s // TODO: optimize to [rsp] (without immediate) when offset is 0 ; movzx eax, BYTE [rsp + ot] ; mov [rsp + oc], eax ), I(B) => x64!(s ; movsx eax, BYTE [rsp + ot] ; mov [rsp + oc], eax ), U(W) => x64!(s ; movzx eax, WORD [rsp + ot] ; mov [rsp + oc], eax ), I(W) => x64!(s ; movsx eax, WORD [rsp + ot] ; mov [rsp + oc], eax ), U(DW) | I(DW) => x64!(s ; mov eax, [rsp + ot] ; mov [rsp + oc], eax ), U(QW) | I(QW) => x64!(s ; mov rax, [rsp + ot] ; mov [rsp + oc], rax ), Buffer => x64!(s ; mov rax, [rsp + ot] ; mov rax, [rax + 8] ; mov [rsp + oc], rax ), } // Section 3.2.3 of the SysV AMD64 ABI: // > The size of each argument gets rounded up to eightbytes. [...] Therefore the stack will always be eightbyte aligned. self.offset_trampoline += 8; self.offset_callee += 8;
debug_assert!( self.allocated_stack == 0 || self.offset_callee <= self.allocated_stack ); } } self.integral_params += 1; }
fn zero_first_arg(&mut self) { debug_assert!( self.integral_params == 0, "the trampoline would zero the first argument after having overridden it with the second one" ); dynasm!(self.assmblr ; .arch x64 ; xor edi, edi ); }
fn cast_return_value(&mut self, rv: NativeType) { let s = &mut self.assmblr; // V8 only supports 32bit integers. We support 8 and 16 bit integers casting them to 32bits. // In SysV-AMD64 the convention dictates that the unused bits of the return value contain garbage, so we // need to zero/sign extend the return value explicitly match rv { NativeType::U8 => x64!(s; movzx eax, al), NativeType::I8 => x64!(s; movsx eax, al), NativeType::U16 => x64!(s; movzx eax, ax), NativeType::I16 => x64!(s; movsx eax, ax), _ => (), } }
fn save_out_array_to_preserved_register(&mut self) { let s = &mut self.assmblr; // functions returning 64 bit integers have the out array appended as their last parameter, // and it is a *FastApiTypedArray<Int32> match self.integral_params { // Trampoline's signature is (receiver, [param0, param1, ...], *FastApiTypedArray) // self.integral_params account only for the original params [param0, param1, ...] // and the out array has not been moved left 0 => x64!(s; mov rbx, [rsi + 8]), 1 => x64!(s; mov rbx, [rdx + 8]), 2 => x64!(s; mov rbx, [rcx + 8]), 3 => x64!(s; mov rbx, [r8 + 8]), 4 => x64!(s; mov rbx, [r9 + 8]), 5.. => { x64!(s ; mov rax, [rsp + self.offset_trampoline as i32] ; mov rbx, [rax + 8] ) } } }
fn wrap_return_value_in_out_array(&mut self) { x64!(self.assmblr; mov [rbx], rax); }
fn save_preserved_register_to_stack(&mut self) { x64!(self.assmblr; push rbx); self.offset_trampoline += 8; // stack pointer has been modified, and the callee stack parameters are expected at the top of the stack self.offset_callee = 0; self.frame_pointer += 8; }
fn recover_preserved_register(&mut self) { debug_assert!( self.frame_pointer >= 8, "the trampoline would try to pop from the stack beyond its frame pointer" ); x64!(self.assmblr; pop rbx); self.frame_pointer -= 8; // parameter offsets are invalid once this method is called }
fn allocate_stack(&mut self, params: &[NativeType]) { let mut int_params = 0u32; let mut float_params = 0u32; for param in params { match param { NativeType::F32 | NativeType::F64 => float_params += 1, _ => int_params += 1, } } let mut stack_size = (int_params.saturating_sub(Self::INTEGRAL_REGISTERS) + float_params.saturating_sub(Self::FLOAT_REGISTERS)) * 8;
// Align new stack frame (accounting for the 8 byte of the trampoline caller's return address // and any other potential addition to the stack prior to this allocation) // Section 3.2.2 of the SysV AMD64 ABI: // > The end of the input argument area shall be aligned on a 16 (32 or 64, if // > __m256 or __m512 is passed on stack) byte boundary. In other words, the value // > (%rsp + 8) is always a multiple of 16 (32 or 64) when control is transferred to // > the function entry point. The stack pointer, %rsp, always points to the end of the // > latest allocated stack frame. stack_size += padding_to_align(16, self.frame_pointer + stack_size + 8);
if stack_size > 0 { x64!(self.assmblr; sub rsp, stack_size as i32); self.offset_trampoline += stack_size; // stack pointer has been modified, and the callee stack parameters are expected at the top of the stack self.offset_callee = 0; self.allocated_stack += stack_size; self.frame_pointer += stack_size; } }
fn deallocate_stack(&mut self) { debug_assert!( self.frame_pointer >= self.allocated_stack, "the trampoline would try to deallocate stack beyond its frame pointer" ); if self.allocated_stack > 0 { x64!(self.assmblr; add rsp, self.allocated_stack as i32);
self.frame_pointer -= self.allocated_stack; self.allocated_stack = 0; } }
fn call(&mut self, ptr: *const c_void) { // the stack has been aligned during stack allocation and/or pushing of preserved registers debug_assert!( (8 + self.frame_pointer) % 16 == 0, "the trampoline would call the FFI function with an unaligned stack" ); x64!(self.assmblr ; mov rax, QWORD ptr as _ ; call rax ); }
fn tailcall(&mut self, ptr: *const c_void) { // stack pointer is never modified and remains aligned // return address remains the one provided by the trampoline's caller (V8) debug_assert!( self.allocated_stack == 0, "the trampoline would tail call the FFI function with an outstanding stack allocation" ); debug_assert!( self.frame_pointer == 0, "the trampoline would tail call the FFI function with outstanding locals in the frame" ); x64!(self.assmblr ; mov rax, QWORD ptr as _ ; jmp rax ); }
fn ret(&mut self) { debug_assert!( self.allocated_stack == 0, "the trampoline would return with an outstanding stack allocation" ); debug_assert!( self.frame_pointer == 0, "the trampoline would return with outstanding locals in the frame" ); x64!(self.assmblr; ret); }
fn is_recv_arg_overridden(&self) -> bool { // V8 receiver is the first parameter of the trampoline function and is a pointer self.integral_params > 0 }
fn must_cast_return_value(&self, rv: NativeType) -> bool { // V8 only supports i32 and u32 return types for integers // We support 8 and 16 bit integers by extending them to 32 bits in the trampoline before returning matches!( rv, NativeType::U8 | NativeType::I8 | NativeType::U16 | NativeType::I16 ) }
fn must_wrap_return_value_in_typed_array(&self, rv: NativeType) -> bool { // V8 only supports i32 and u32 return types for integers // We support 64 bit integers by wrapping them in a TypedArray out parameter crate::needs_unwrap(rv) }
fn finalize(self) -> ExecutableBuffer { self.assmblr.finalize().unwrap() }}
struct Aarch64Apple { // Reference https://github.com/ARM-software/abi-aa/blob/main/aapcs64/aapcs64.rst assmblr: dynasmrt::aarch64::Assembler, // Parameter counters integral_params: u32, float_params: u32, // Stack offset accumulators offset_trampoline: u32, offset_callee: u32, allocated_stack: u32,}
#[cfg_attr( not(all(target_aarch = "aarch64", target_vendor = "apple")), allow(dead_code))]impl Aarch64Apple { // Integral arguments go to the first 8 GPR: x0-x7 const INTEGRAL_REGISTERS: u32 = 8; // Floating-point arguments go to the first 8 SIMD & Floating-Point registers: v0-v1 const FLOAT_REGISTERS: u32 = 8;
fn new() -> Self { Self { assmblr: dynasmrt::aarch64::Assembler::new().unwrap(), integral_params: 0, float_params: 0, offset_trampoline: 0, offset_callee: 0, allocated_stack: 0, } }
fn compile(sym: &Symbol) -> Trampoline { let mut compiler = Self::new();
let must_wrap_return_value = compiler.must_wrap_return_value_in_typed_array(sym.result_type); let must_save_preserved_register = must_wrap_return_value; let cannot_tailcall = must_wrap_return_value;
if cannot_tailcall { compiler.allocate_stack(sym); compiler.save_frame_record(); if compiler.must_save_preserved_register_to_stack(sym) { compiler.save_preserved_register_to_stack(); } }
for param in sym.parameter_types.iter().copied() { compiler.move_left(param) } if !compiler.is_recv_arg_overridden() { // the receiver object should never be expected. Avoid its unexpected or deliberate leak compiler.zero_first_arg(); } if compiler.must_wrap_return_value_in_typed_array(sym.result_type) { compiler.save_out_array_to_preserved_register(); }
if cannot_tailcall { compiler.call(sym.ptr.as_ptr()); if must_wrap_return_value { compiler.wrap_return_value_in_out_array(); } if must_save_preserved_register { compiler.recover_preserved_register(); } compiler.recover_frame_record(); compiler.deallocate_stack(); compiler.ret(); } else { compiler.tailcall(sym.ptr.as_ptr()); }
Trampoline(compiler.finalize()) }
fn move_left(&mut self, param: NativeType) { // Section 6.4.2 of the Aarch64 Procedure Call Standard (PCS), on argument classification: // - INTEGRAL or POINTER: // > If the argument is an Integral or Pointer Type, the size of the argument is less than or equal to 8 bytes // > and the NGRN is less than 8, the argument is copied to the least significant bits in x[NGRN]. // // - Floating-Point or Vector: // > If the argument is a Half-, Single-, Double- or Quad- precision Floating-point or short vector type // > and the NSRN is less than 8, then the argument is allocated to the least significant bits of register v[NSRN] match param.into() { Int(integral) => self.move_integral(integral), Float(float) => self.move_float(float), } }
fn move_float(&mut self, param: Floating) { // Section 6.4.2 of the Aarch64 PCS: // > If the argument is a Half-, Single-, Double- or Quad- precision Floating-point or short vector type and the NSRN is less than 8, then the // > argument is allocated to the least significant bits of register v[NSRN]. The NSRN is incremented by one. The argument has now been allocated. // > [if NSRN is equal or more than 8] // > The argument is copied to memory at the adjusted NSAA. The NSAA is incremented by the size of the argument. The argument has now been allocated. let param_i = self.float_params;
let is_in_stack = param_i >= Self::FLOAT_REGISTERS; if is_in_stack { // https://developer.apple.com/documentation/xcode/writing-arm64-code-for-apple-platforms: // > Function arguments may consume slots on the stack that are not multiples of 8 bytes. // (i.e. natural alignment instead of eightbyte alignment) let padding_trampl = (param.size() - self.offset_trampoline % param.size()) % param.size(); let padding_callee = (param.size() - self.offset_callee % param.size()) % param.size();
// floats are only moved to accommodate integer movement in the stack let stack_has_moved = self.integral_params >= Self::INTEGRAL_REGISTERS; if stack_has_moved { let s = &mut self.assmblr; let ot = self.offset_trampoline; let oc = self.offset_callee; match param { Single => aarch64!(s // 6.1.2 Aarch64 PCS: // > Registers v8-v15 must be preserved by a callee across subroutine calls; // > the remaining registers (v0-v7, v16-v31) do not need to be preserved (or should be preserved by the caller). ; ldr s16, [sp, ot + padding_trampl] ; str s16, [sp, oc + padding_callee] ), Double => aarch64!(s ; ldr d16, [sp, ot + padding_trampl] ; str d16, [sp, oc + padding_callee] ), } } self.offset_trampoline += padding_trampl + param.size(); self.offset_callee += padding_callee + param.size();
debug_assert!( self.allocated_stack == 0 || self.offset_callee <= self.allocated_stack ); } self.float_params += 1; }
fn move_integral(&mut self, param: Integral) { let s = &mut self.assmblr; // Section 6.4.2 of the Aarch64 PCS: // If the argument is an Integral or Pointer Type, the size of the argument is less than or // equal to 8 bytes and the NGRN is less than 8, the argument is copied to the least // significant bits in x[NGRN]. The NGRN is incremented by one. The argument has now been // allocated. // [if NGRN is equal or more than 8] // The argument is copied to memory at the adjusted NSAA. The NSAA is incremented by the size // of the argument. The argument has now been allocated. let param_i = self.integral_params;
// move each argument one position to the left. The first argument in the stack moves to the last integer register (x7). match (param_i, param) { // From https://developer.apple.com/documentation/xcode/writing-arm64-code-for-apple-platforms: // > The caller of a function is responsible for signing or zero-extending any argument with fewer than 32 bits. // > The standard ABI expects the callee to sign or zero-extend those arguments. // (this applies to register parameters, as stack parameters are not eightbyte aligned in Apple) (0, I(B)) => aarch64!(s; sxtb w0, w1), (0, U(B)) => aarch64!(s; and w0, w1, 0xFF), (0, I(W)) => aarch64!(s; sxth w0, w1), (0, U(W)) => aarch64!(s; and w0, w1, 0xFFFF), (0, I(DW) | U(DW)) => aarch64!(s; mov w0, w1), (0, I(QW) | U(QW)) => aarch64!(s; mov x0, x1), // The fast API expects buffer arguments passed as a pointer to a FastApiTypedArray<Uint8> struct // Here we blindly follow the layout of https://github.com/denoland/rusty_v8/blob/main/src/fast_api.rs#L190-L200 // although that might be problematic: https://discord.com/channels/684898665143206084/956626010248478720/1009450940866252823 (0, Buffer) => aarch64!(s; ldr x0, [x1, 8]),
(1, I(B)) => aarch64!(s; sxtb w1, w2), (1, U(B)) => aarch64!(s; and w1, w2, 0xFF), (1, I(W)) => aarch64!(s; sxth w1, w2), (1, U(W)) => aarch64!(s; and w1, w2, 0xFFFF), (1, I(DW) | U(DW)) => aarch64!(s; mov w1, w2), (1, I(QW) | U(QW)) => aarch64!(s; mov x1, x2), (1, Buffer) => aarch64!(s; ldr x1, [x2, 8]),
(2, I(B)) => aarch64!(s; sxtb w2, w3), (2, U(B)) => aarch64!(s; and w2, w3, 0xFF), (2, I(W)) => aarch64!(s; sxth w2, w3), (2, U(W)) => aarch64!(s; and w2, w3, 0xFFFF), (2, I(DW) | U(DW)) => aarch64!(s; mov w2, w3), (2, I(QW) | U(QW)) => aarch64!(s; mov x2, x3), (2, Buffer) => aarch64!(s; ldr x2, [x3, 8]),
(3, I(B)) => aarch64!(s; sxtb w3, w4), (3, U(B)) => aarch64!(s; and w3, w4, 0xFF), (3, I(W)) => aarch64!(s; sxth w3, w4), (3, U(W)) => aarch64!(s; and w3, w4, 0xFFFF), (3, I(DW) | U(DW)) => aarch64!(s; mov w3, w4), (3, I(QW) | U(QW)) => aarch64!(s; mov x3, x4), (3, Buffer) => aarch64!(s; ldr x3, [x4, 8]),
(4, I(B)) => aarch64!(s; sxtb w4, w5), (4, U(B)) => aarch64!(s; and w4, w5, 0xFF), (4, I(W)) => aarch64!(s; sxth w4, w5), (4, U(W)) => aarch64!(s; and w4, w5, 0xFFFF), (4, I(DW) | U(DW)) => aarch64!(s; mov w4, w5), (4, I(QW) | U(QW)) => aarch64!(s; mov x4, x5), (4, Buffer) => aarch64!(s; ldr x4, [x5, 8]),
(5, I(B)) => aarch64!(s; sxtb w5, w6), (5, U(B)) => aarch64!(s; and w5, w6, 0xFF), (5, I(W)) => aarch64!(s; sxth w5, w6), (5, U(W)) => aarch64!(s; and w5, w6, 0xFFFF), (5, I(DW) | U(DW)) => aarch64!(s; mov w5, w6), (5, I(QW) | U(QW)) => aarch64!(s; mov x5, x6), (5, Buffer) => aarch64!(s; ldr x5, [x6, 8]),
(6, I(B)) => aarch64!(s; sxtb w6, w7), (6, U(B)) => aarch64!(s; and w6, w7, 0xFF), (6, I(W)) => aarch64!(s; sxth w6, w7), (6, U(W)) => aarch64!(s; and w6, w7, 0xFFFF), (6, I(DW) | U(DW)) => aarch64!(s; mov w6, w7), (6, I(QW) | U(QW)) => aarch64!(s; mov x6, x7), (6, Buffer) => aarch64!(s; ldr x6, [x7, 8]),
(7, param) => { let ot = self.offset_trampoline; match param { I(B) => { aarch64!(s; ldrsb w7, [sp, ot]) } U(B) => { // ldrb zero-extends the byte to fill the 32bits of the register aarch64!(s; ldrb w7, [sp, ot]) } I(W) => { aarch64!(s; ldrsh w7, [sp, ot]) } U(W) => { // ldrh zero-extends the half-word to fill the 32bits of the register aarch64!(s; ldrh w7, [sp, ot]) } I(DW) | U(DW) => { aarch64!(s; ldr w7, [sp, ot]) } I(QW) | U(QW) => { aarch64!(s; ldr x7, [sp, ot]) } Buffer => { aarch64!(s ; ldr x7, [sp, ot] ; ldr x7, [x7, 8] ) } } // 16 and 8 bit integers are 32 bit integers in v8 self.offset_trampoline += max(param.size(), 4); }
(8.., param) => { // https://developer.apple.com/documentation/xcode/writing-arm64-code-for-apple-platforms: // > Function arguments may consume slots on the stack that are not multiples of 8 bytes. // (i.e. natural alignment instead of eightbyte alignment) // // N.B. V8 does not currently follow this Apple's policy, and instead aligns all arguments to 8 Byte boundaries. // The current implementation follows the V8 incorrect calling convention for the sake of a seamless experience // for the Deno users. Whenever upgrading V8 we should make sure that the bug has not been amended, and revert this // workaround once it has been. The bug is being tracked in https://bugs.chromium.org/p/v8/issues/detail?id=13171 let size_original = param.size(); // 16 and 8 bit integers are 32 bit integers in v8 // let size_trampl = max(size_original, 4); // <-- Apple alignment let size_trampl = 8; // <-- V8 incorrect alignment let padding_trampl = padding_to_align(size_trampl, self.offset_trampoline); let padding_callee = padding_to_align(size_original, self.offset_callee); let ot = self.offset_trampoline; let oc = self.offset_callee; match param { I(B) | U(B) => aarch64!(s ; ldr w8, [sp, ot + padding_trampl] ; strb w8, [sp, oc + padding_callee] ), I(W) | U(W) => aarch64!(s ; ldr w8, [sp, ot + padding_trampl] ; strh w8, [sp, oc + padding_callee] ), I(DW) | U(DW) => aarch64!(s ; ldr w8, [sp, ot + padding_trampl] ; str w8, [sp, oc + padding_callee] ), I(QW) | U(QW) => aarch64!(s ; ldr x8, [sp, ot + padding_trampl] ; str x8, [sp, oc + padding_callee] ), Buffer => aarch64!(s ; ldr x8, [sp, ot + padding_trampl] ; ldr x8, [x8, 8] ; str x8, [sp, oc + padding_callee] ), } self.offset_trampoline += padding_trampl + size_trampl; self.offset_callee += padding_callee + size_original;
debug_assert!( self.allocated_stack == 0 || self.offset_callee <= self.allocated_stack ); } }; self.integral_params += 1; }
fn zero_first_arg(&mut self) { debug_assert!( self.integral_params == 0, "the trampoline would zero the first argument after having overridden it with the second one" ); aarch64!(self.assmblr; mov x0, xzr); }
fn save_out_array_to_preserved_register(&mut self) { let s = &mut self.assmblr; // functions returning 64 bit integers have the out array appended as their last parameter, // and it is a *FastApiTypedArray<Int32> match self.integral_params { // x0 is always V8's receiver 0 => aarch64!(s; ldr x19, [x1, 8]), 1 => aarch64!(s; ldr x19, [x2, 8]), 2 => aarch64!(s; ldr x19, [x3, 8]), 3 => aarch64!(s; ldr x19, [x4, 8]), 4 => aarch64!(s; ldr x19, [x5, 8]), 5 => aarch64!(s; ldr x19, [x6, 8]), 6 => aarch64!(s; ldr x19, [x7, 8]), 7.. => { aarch64!(s ; ldr x19, [sp, self.offset_trampoline] ; ldr x19, [x19, 8] ) } } }
fn wrap_return_value_in_out_array(&mut self) { aarch64!(self.assmblr; str x0, [x19]); }
fn save_frame_record(&mut self) { debug_assert!( self.allocated_stack >= 16, "the trampoline would try to save the frame record to the stack without having allocated enough space for it" ); aarch64!(self.assmblr // Frame record is stored at the bottom of the stack frame ; stp x29, x30, [sp, self.allocated_stack - 16] ; add x29, sp, self.allocated_stack - 16 ) }
fn recover_frame_record(&mut self) { // The stack cannot have been deallocated before the frame record is restored debug_assert!( self.allocated_stack >= 16, "the trampoline would try to load the frame record from the stack, but it couldn't possibly contain it" ); // Frame record is stored at the bottom of the stack frame aarch64!(self.assmblr; ldp x29, x30, [sp, self.allocated_stack - 16]) }
fn save_preserved_register_to_stack(&mut self) { // If a preserved register needs to be used, we must have allocated at least 32 bytes in the stack // 16 for the frame record, 8 for the preserved register, and 8 for 16-byte alignment. debug_assert!( self.allocated_stack >= 32, "the trampoline would try to save a register to the stack without having allocated enough space for it" ); // preserved register is stored after frame record aarch64!(self.assmblr; str x19, [sp, self.allocated_stack - 24]); }
fn recover_preserved_register(&mut self) { // The stack cannot have been deallocated before the preserved register is restored // 16 for the frame record, 8 for the preserved register, and 8 for 16-byte alignment. debug_assert!( self.allocated_stack >= 32, "the trampoline would try to recover the value of a register from the stack, but it couldn't possibly contain it" ); // preserved register is stored after frame record aarch64!(self.assmblr; ldr x19, [sp, self.allocated_stack - 24]); }
fn allocate_stack(&mut self, symbol: &Symbol) { // https://developer.apple.com/documentation/xcode/writing-arm64-code-for-apple-platforms: // > Function arguments may consume slots on the stack that are not multiples of 8 bytes. // (i.e. natural alignment instead of eightbyte alignment) let mut int_params = 0u32; let mut float_params = 0u32; let mut stack_size = 0u32; for param in symbol.parameter_types.iter().copied() { match param.into() { Float(float_param) => { float_params += 1; if float_params > Self::FLOAT_REGISTERS { stack_size += float_param.size(); } } Int(integral_param) => { int_params += 1; if int_params > Self::INTEGRAL_REGISTERS { stack_size += integral_param.size(); } } } }
// Section 6.2.3 of the Aarch64 PCS: // > Each frame shall link to the frame of its caller by means of a frame record of two 64-bit values on the stack stack_size += 16;
if self.must_save_preserved_register_to_stack(symbol) { stack_size += 8; }
// Section 6.2.2 of Aarch64 PCS: // > At any point at which memory is accessed via SP, the hardware requires that // > - SP mod 16 = 0. The stack must be quad-word aligned. // > The stack must also conform to the following constraint at a public interface: // > - SP mod 16 = 0. The stack must be quad-word aligned. stack_size += padding_to_align(16, stack_size);
if stack_size > 0 { aarch64!(self.assmblr; sub sp, sp, stack_size); self.offset_trampoline += stack_size; // stack pointer has been modified, and the callee stack parameters are expected at the top of the stack self.offset_callee = 0; self.allocated_stack += stack_size; } }
fn deallocate_stack(&mut self) { if self.allocated_stack > 0 { aarch64!(self.assmblr; add sp, sp, self.allocated_stack); self.allocated_stack = 0; } }
fn call(&mut self, ptr: *const c_void) { // the stack has been aligned during stack allocation // Frame record has been stored in stack and frame pointer points to it debug_assert!( self.allocated_stack % 16 == 0, "the trampoline would call the FFI function with an unaligned stack" ); debug_assert!( self.allocated_stack >= 16, "the trampoline would call the FFI function without allocating enough stack for the frame record" ); self.load_callee_address(ptr); aarch64!(self.assmblr; blr x8); }
fn tailcall(&mut self, ptr: *const c_void) { // stack pointer is never modified and remains aligned // frame pointer and link register remain the one provided by the trampoline's caller (V8) debug_assert!( self.allocated_stack == 0, "the trampoline would tail call the FFI function with an outstanding stack allocation" ); self.load_callee_address(ptr); aarch64!(self.assmblr; br x8); }
fn ret(&mut self) { debug_assert!( self.allocated_stack == 0, "the trampoline would return with an outstanding stack allocation" ); aarch64!(self.assmblr; ret); }
fn load_callee_address(&mut self, ptr: *const c_void) { // Like all ARM instructions, move instructions are 32bit long and can fit at most 16bit immediates. // bigger immediates are loaded in multiple steps applying a left-shift modifier let mut address = ptr as u64; let mut imm16 = address & 0xFFFF; aarch64!(self.assmblr; movz x8, imm16 as u32); address >>= 16; let mut shift = 16; while address > 0 { imm16 = address & 0xFFFF; if imm16 != 0 { aarch64!(self.assmblr; movk x8, imm16 as u32, lsl shift); } address >>= 16; shift += 16; } }
fn is_recv_arg_overridden(&self) -> bool { // V8 receiver is the first parameter of the trampoline function and is a pointer self.integral_params > 0 }
fn must_save_preserved_register_to_stack(&mut self, symbol: &Symbol) -> bool { self.must_wrap_return_value_in_typed_array(symbol.result_type) }
fn must_wrap_return_value_in_typed_array(&self, rv: NativeType) -> bool { // V8 only supports i32 and u32 return types for integers // We support 64 bit integers by wrapping them in a TypedArray out parameter crate::needs_unwrap(rv) }
fn finalize(self) -> ExecutableBuffer { self.assmblr.finalize().unwrap() }}
struct Win64 { // Reference: https://github.com/MicrosoftDocs/cpp-docs/blob/main/docs/build/x64-calling-convention.md assmblr: dynasmrt::x64::Assembler, // Params counter (Windows does not distinguish by type with regards to parameter position) params: u32, // Stack offset accumulators offset_trampoline: u32, offset_callee: u32, allocated_stack: u32, frame_pointer: u32,}
#[cfg_attr( not(all(target_aarch = "x86_64", target_family = "windows")), allow(dead_code))]impl Win64 { // Section "Parameter Passing" of the Windows x64 calling convention: // > By default, the x64 calling convention passes the first four arguments to a function in registers. const REGISTERS: u32 = 4;
fn new() -> Self { Self { assmblr: dynasmrt::x64::Assembler::new().unwrap(), params: 0, // trampoline caller's return address + trampoline's shadow space offset_trampoline: 8 + 32, offset_callee: 8 + 32, allocated_stack: 0, frame_pointer: 0, } }
fn compile(sym: &Symbol) -> Trampoline { let mut compiler = Self::new();
let must_cast_return_value = compiler.must_cast_return_value(sym.result_type); let must_wrap_return_value = compiler.must_wrap_return_value_in_typed_array(sym.result_type); let must_save_preserved_register = must_wrap_return_value; let cannot_tailcall = must_cast_return_value || must_wrap_return_value;
if cannot_tailcall { if must_save_preserved_register { compiler.save_preserved_register_to_stack(); } compiler.allocate_stack(&sym.parameter_types); }
for param in sym.parameter_types.iter().copied() { compiler.move_left(param) } if !compiler.is_recv_arg_overridden() { // the receiver object should never be expected. Avoid its unexpected or deliberate leak compiler.zero_first_arg(); } if must_wrap_return_value { compiler.save_out_array_to_preserved_register(); }
if cannot_tailcall { compiler.call(sym.ptr.as_ptr()); if must_cast_return_value { compiler.cast_return_value(sym.result_type); } if must_wrap_return_value { compiler.wrap_return_value_in_out_array(); } compiler.deallocate_stack(); if must_save_preserved_register { compiler.recover_preserved_register(); } compiler.ret(); } else { compiler.tailcall(sym.ptr.as_ptr()); }
Trampoline(compiler.finalize()) }
fn move_left(&mut self, param: NativeType) { // Section "Parameter Passing" of the Windows x64 calling convention: // > By default, the x64 calling convention passes the first four arguments to a function in registers. // > The registers used for these arguments depend on the position and type of the argument. // > Remaining arguments get pushed on the stack in right-to-left order. // > [...] // > Integer valued arguments in the leftmost four positions are passed in left-to-right order in RCX, RDX, R8, and R9 // > [...] // > Any floating-point and double-precision arguments in the first four parameters are passed in XMM0 - XMM3, depending on position let s = &mut self.assmblr; let param_i = self.params;
// move each argument one position to the left. The first argument in the stack moves to the last register (r9 or xmm3). // If the FFI function is called with a new stack frame, the arguments remaining in the stack are copied to the new stack frame. // Otherwise, they are copied 8 bytes lower in the same frame match (param_i, param.into()) { // Section "Parameter Passing" of the Windows x64 calling convention: // > All integer arguments in registers are right-justified, so the callee can ignore the upper bits of the register // > and access only the portion of the register necessary. // (i.e. unlike in SysV or Aarch64-Apple, 8/16 bit integers are not expected to be zero/sign extended) (0, Int(U(B | W | DW) | I(B | W | DW))) => x64!(s; mov ecx, edx), (0, Int(U(QW) | I(QW))) => x64!(s; mov rcx, rdx), // The fast API expects buffer arguments passed as a pointer to a FastApiTypedArray<Uint8> struct // Here we blindly follow the layout of https://github.com/denoland/rusty_v8/blob/main/src/fast_api.rs#L190-L200 // although that might be problematic: https://discord.com/channels/684898665143206084/956626010248478720/1009450940866252823 (0, Int(Buffer)) => x64!(s; mov rcx, [rdx + 8]), // Use movaps for singles and doubles, benefits of smaller encoding outweigh those of using the correct instruction for the type, // which for doubles should technically be movapd (0, Float(_)) => { x64!(s; movaps xmm0, xmm1); self.zero_first_arg(); }
(1, Int(U(B | W | DW) | I(B | W | DW))) => x64!(s; mov edx, r8d), (1, Int(U(QW) | I(QW))) => x64!(s; mov rdx, r8), (1, Int(Buffer)) => x64!(s; mov rdx, [r8 + 8]), (1, Float(_)) => x64!(s; movaps xmm1, xmm2),
(2, Int(U(B | W | DW) | I(B | W | DW))) => x64!(s; mov r8d, r9d), (2, Int(U(QW) | I(QW))) => x64!(s; mov r8, r9), (2, Int(Buffer)) => x64!(s; mov r8, [r9 + 8]), (2, Float(_)) => x64!(s; movaps xmm2, xmm3),
(3, param) => { let ot = self.offset_trampoline as i32; match param { Int(U(B | W | DW) | I(B | W | DW)) => { x64!(s; mov r9d, [rsp + ot]) } Int(U(QW) | I(QW)) => { x64!(s; mov r9, [rsp + ot]) } Int(Buffer) => { x64!(s ; mov r9, [rsp + ot] ; mov r9, [r9 + 8]) } Float(_) => { // parameter 4 is always 16-byte aligned, so we can use movaps instead of movups x64!(s; movaps xmm3, [rsp + ot]) } } // Section "x64 Aggregate and Union layout" of the windows x64 software conventions doc: // > The alignment of the beginning of a structure or a union is the maximum alignment of any individual member // Ref: https://github.com/MicrosoftDocs/cpp-docs/blob/main/docs/build/x64-software-conventions.md#x64-aggregate-and-union-layout self.offset_trampoline += 8; } (4.., param) => { let ot = self.offset_trampoline as i32; let oc = self.offset_callee as i32; match param { Int(U(B | W | DW) | I(B | W | DW)) => { x64!(s ; mov eax, [rsp + ot] ; mov [rsp + oc], eax ) } Int(U(QW) | I(QW)) => { x64!(s ; mov rax, [rsp + ot] ; mov [rsp + oc], rax ) } Int(Buffer) => { x64!(s ; mov rax, [rsp + ot] ; mov rax, [rax + 8] ; mov [rsp + oc], rax ) } Float(_) => { x64!(s ; movups xmm4, [rsp + ot] ; movups [rsp + oc], xmm4 ) } } // Section "x64 Aggregate and Union layout" of the windows x64 software conventions doc: // > The alignment of the beginning of a structure or a union is the maximum alignment of any individual member // Ref: https://github.com/MicrosoftDocs/cpp-docs/blob/main/docs/build/x64-software-conventions.md#x64-aggregate-and-union-layout self.offset_trampoline += 8; self.offset_callee += 8;
debug_assert!( self.allocated_stack == 0 || self.offset_callee <= self.allocated_stack ); } } self.params += 1; }
fn zero_first_arg(&mut self) { debug_assert!( self.params == 0, "the trampoline would zero the first argument after having overridden it with the second one" ); x64!(self.assmblr; xor ecx, ecx); }
fn cast_return_value(&mut self, rv: NativeType) { let s = &mut self.assmblr; // V8 only supports 32bit integers. We support 8 and 16 bit integers casting them to 32bits. // Section "Return Values" of the Windows x64 Calling Convention doc: // > The state of unused bits in the value returned in RAX or XMM0 is undefined. match rv { NativeType::U8 => x64!(s; movzx eax, al), NativeType::I8 => x64!(s; movsx eax, al), NativeType::U16 => x64!(s; movzx eax, ax), NativeType::I16 => x64!(s; movsx eax, ax), _ => (), } }
fn save_out_array_to_preserved_register(&mut self) { let s = &mut self.assmblr; // functions returning 64 bit integers have the out array appended as their last parameter, // and it is a *FastApiTypedArray<Int32> match self.params { // rcx is always V8 receiver 0 => x64!(s; mov rbx, [rdx + 8]), 1 => x64!(s; mov rbx, [r8 + 8]), 2 => x64!(s; mov rbx, [r9 + 8]), 3.. => { x64!(s ; mov rax, [rsp + self.offset_trampoline as i32] ; mov rbx, [rax + 8] ) } } }
fn wrap_return_value_in_out_array(&mut self) { x64!(self.assmblr; mov [rbx], rax) }
fn save_preserved_register_to_stack(&mut self) { x64!(self.assmblr; push rbx); self.offset_trampoline += 8; // stack pointer has been modified, and the callee stack parameters are expected at the top of the stack self.offset_callee = 0; self.frame_pointer += 8; }
fn recover_preserved_register(&mut self) { debug_assert!( self.frame_pointer >= 8, "the trampoline would try to pop from the stack beyond its frame pointer" ); x64!(self.assmblr; pop rbx); self.frame_pointer -= 8; // parameter offsets are invalid once this method is called }
fn allocate_stack(&mut self, params: &[NativeType]) { let mut stack_size = 0; // Section "Calling Convention Defaults" of the x64-calling-convention and Section "Stack Allocation" of the stack-usage docs: // > The x64 Application Binary Interface (ABI) uses a four-register fast-call calling convention by default. // > Space is allocated on the call stack as a shadow store for callees to save those registers. // > [...] // > Any parameters beyond the first four must be stored on the stack after the shadow store before the call // > [...] // > Even if the called function has fewer than 4 parameters, these 4 stack locations are effectively owned by the called function, // > and may be used by the called function for other purposes besides saving parameter register values stack_size += max(params.len() as u32, 4) * 8;
// Align new stack frame (accounting for the 8 byte of the trampoline caller's return address // and any other potential addition to the stack prior to this allocation) // Section "Stack Allocation" of stack-usage docs: // > The stack will always be maintained 16-byte aligned, except within the prolog (for example, after the return address is pushed) stack_size += padding_to_align(16, self.frame_pointer + stack_size + 8);
x64!(self.assmblr; sub rsp, stack_size as i32); self.offset_trampoline += stack_size; // stack pointer has been modified, and the callee stack parameters are expected at the top of the stack right after the shadow space self.offset_callee = 32; self.allocated_stack += stack_size; self.frame_pointer += stack_size; }
fn deallocate_stack(&mut self) { debug_assert!( self.frame_pointer >= self.allocated_stack, "the trampoline would try to deallocate stack beyond its frame pointer" ); x64!(self.assmblr; add rsp, self.allocated_stack as i32); self.frame_pointer -= self.allocated_stack; self.allocated_stack = 0; }
fn call(&mut self, ptr: *const c_void) { // the stack has been aligned during stack allocation and/or pushing of preserved registers debug_assert!( (8 + self.frame_pointer) % 16 == 0, "the trampoline would call the FFI function with an unaligned stack" ); x64!(self.assmblr ; mov rax, QWORD ptr as _ ; call rax ); }
fn tailcall(&mut self, ptr: *const c_void) { // stack pointer is never modified and remains aligned // return address remains the one provided by the trampoline's caller (V8) debug_assert!( self.allocated_stack == 0, "the trampoline would tail call the FFI function with an outstanding stack allocation" ); debug_assert!( self.frame_pointer == 0, "the trampoline would tail call the FFI function with outstanding locals in the frame" ); x64!(self.assmblr ; mov rax, QWORD ptr as _ ; jmp rax ); }
fn ret(&mut self) { debug_assert!( self.allocated_stack == 0, "the trampoline would return with an outstanding stack allocation" ); debug_assert!( self.frame_pointer == 0, "the trampoline would return with outstanding locals in the frame" ); x64!(self.assmblr; ret); }
fn is_recv_arg_overridden(&self) -> bool { self.params > 0 }
fn must_cast_return_value(&self, rv: NativeType) -> bool { // V8 only supports i32 and u32 return types for integers // We support 8 and 16 bit integers by extending them to 32 bits in the trampoline before returning matches!( rv, NativeType::U8 | NativeType::I8 | NativeType::U16 | NativeType::I16 ) }
fn must_wrap_return_value_in_typed_array(&self, rv: NativeType) -> bool { // V8 only supports i32 and u32 return types for integers // We support 64 bit integers by wrapping them in a TypedArray out parameter crate::needs_unwrap(rv) }
fn finalize(self) -> ExecutableBuffer { self.assmblr.finalize().unwrap() }}
fn padding_to_align(alignment: u32, size: u32) -> u32 { (alignment - size % alignment) % alignment}
#[derive(Clone, Copy, Debug)]enum Floating { Single = 4, Double = 8,}
impl Floating { fn size(self) -> u32 { self as u32 }}
use Floating::*;
#[derive(Clone, Copy, Debug)]enum Integral { I(Size), U(Size), Buffer,}
impl Integral { fn size(self) -> u32 { match self { I(size) | U(size) => size as u32, Buffer => 8, } }}
use Integral::*;
#[derive(Clone, Copy, Debug)]enum Size { B = 1, W = 2, DW = 4, QW = 8,}use Size::*;
#[allow(clippy::enum_variant_names)]#[derive(Clone, Copy, Debug)]enum Param { Int(Integral), Float(Floating),}
use Param::*;
impl From<NativeType> for Param { fn from(native: NativeType) -> Self { match native { NativeType::F32 => Float(Single), NativeType::F64 => Float(Double), NativeType::Bool | NativeType::U8 => Int(U(B)), NativeType::U16 => Int(U(W)), NativeType::U32 | NativeType::Void => Int(U(DW)), NativeType::U64 | NativeType::USize | NativeType::Pointer | NativeType::Function => Int(U(QW)), NativeType::I8 => Int(I(B)), NativeType::I16 => Int(I(W)), NativeType::I32 => Int(I(DW)), NativeType::I64 | NativeType::ISize => Int(I(QW)), NativeType::Buffer => Int(Buffer), } }}
#[cfg(test)]mod tests { use std::ptr::null_mut;
use libffi::middle::Type;
use crate::NativeType; use crate::Symbol;
fn symbol(parameters: Vec<NativeType>, ret: NativeType) -> Symbol { Symbol { cif: libffi::middle::Cif::new(vec![], Type::void()), ptr: libffi::middle::CodePtr(null_mut()), parameter_types: parameters, result_type: ret, can_callback: false, } }
mod sysv_amd64 { use std::ops::Deref;
use dynasmrt::dynasm; use dynasmrt::DynasmApi;
use super::super::SysVAmd64; use super::symbol; use crate::NativeType::*;
#[test] fn tailcall() { let trampoline = SysVAmd64::compile(&symbol( vec![ U8, U16, I16, I8, U32, U64, Buffer, Function, I64, I32, I16, I8, F32, F32, F32, F32, F64, F64, F64, F64, F32, F64, ], Void, ));
let mut assembler = dynasmrt::x64::Assembler::new().unwrap(); // See https://godbolt.org/z/KE9x1h9xq dynasm!(assembler ; .arch x64 ; movzx edi, sil // u8 ; movzx esi, dx // u16 ; movsx edx, cx // i16 ; movsx ecx, r8b // i8 ; mov r8d, r9d // u32 ; mov r9, [DWORD rsp + 8] // u64 ; mov rax, [DWORD rsp + 16] // Buffer ; mov rax, [rax + 8] // .. ; mov [DWORD rsp + 8], rax // .. ; mov rax, [DWORD rsp + 24] // Function ; mov [DWORD rsp + 16], rax // .. ; mov rax, [DWORD rsp + 32] // i64 ; mov [DWORD rsp + 24], rax // .. ; mov eax, [DWORD rsp + 40] // i32 ; mov [DWORD rsp + 32], eax // .. ; movsx eax, WORD [DWORD rsp + 48] // i16 ; mov [DWORD rsp + 40], eax // .. ; movsx eax, BYTE [DWORD rsp + 56] // i8 ; mov [DWORD rsp + 48], eax // .. ; movss xmm8, [DWORD rsp + 64] // f32 ; movss [DWORD rsp + 56], xmm8 // .. ; movsd xmm8, [DWORD rsp + 72] // f64 ; movsd [DWORD rsp + 64], xmm8 // .. ; mov rax, QWORD 0 ; jmp rax ); let expected = assembler.finalize().unwrap(); assert_eq!(trampoline.0.deref(), expected.deref()); }
#[test] fn integer_casting() { let trampoline = SysVAmd64::compile(&symbol( vec![U8, U16, I8, I16, U8, U16, I8, I16, U8, U16, I8, I16], I8, ));
let mut assembler = dynasmrt::x64::Assembler::new().unwrap(); // See https://godbolt.org/z/qo59bPsfv dynasm!(assembler ; .arch x64 ; sub rsp, DWORD 56 // stack allocation ; movzx edi, sil // u8 ; movzx esi, dx // u16 ; movsx edx, cl // i8 ; movsx ecx, r8w // i16 ; movzx r8d, r9b // u8 ; movzx r9d, WORD [DWORD rsp + 64] // u16 ; movsx eax, BYTE [DWORD rsp + 72] // i8 ; mov [DWORD rsp + 0], eax // .. ; movsx eax, WORD [DWORD rsp + 80] // i16 ; mov [DWORD rsp + 8], eax // .. ; movzx eax, BYTE [DWORD rsp + 88] // u8 ; mov [DWORD rsp + 16], eax // .. ; movzx eax, WORD [DWORD rsp + 96] // u16 ; mov [DWORD rsp + 24], eax // .. ; movsx eax, BYTE [DWORD rsp + 104] // i8 ; mov [DWORD rsp + 32], eax // .. ; movsx eax, WORD [DWORD rsp + 112] // i16 ; mov [DWORD rsp + 40], eax // .. ; mov rax, QWORD 0 ; call rax ; movsx eax, al // return value cast ; add rsp, DWORD 56 // stack deallocation ; ret ); let expected = assembler.finalize().unwrap(); assert_eq!(trampoline.0.deref(), expected.deref()); }
#[test] fn buffer_parameters() { let trampoline = SysVAmd64::compile(&symbol( vec![ Buffer, Buffer, Buffer, Buffer, Buffer, Buffer, Buffer, Buffer, ], Void, ));
let mut assembler = dynasmrt::x64::Assembler::new().unwrap(); // See https://godbolt.org/z/hqv63M3Ko dynasm!(assembler ; .arch x64 ; mov rdi, [rsi + 8] // Buffer ; mov rsi, [rdx + 8] // Buffer ; mov rdx, [rcx + 8] // Buffer ; mov rcx, [r8 + 8] // Buffer ; mov r8, [r9 + 8] // Buffer ; mov r9, [DWORD rsp + 8] // Buffer ; mov r9, [r9 + 8] // .. ; mov rax, [DWORD rsp + 16] // Buffer ; mov rax, [rax + 8] // .. ; mov [DWORD rsp + 8], rax // .. ; mov rax, [DWORD rsp + 24] // Buffer ; mov rax, [rax + 8] // .. ; mov [DWORD rsp + 16], rax // .. ; mov rax, QWORD 0 ; jmp rax ); let expected = assembler.finalize().unwrap(); assert_eq!(trampoline.0.deref(), expected.deref()); }
#[test] fn return_u64_in_register_typed_array() { let trampoline = SysVAmd64::compile(&symbol(vec![], U64));
let mut assembler = dynasmrt::x64::Assembler::new().unwrap(); // See https://godbolt.org/z/8G7a488o7 dynasm!(assembler ; .arch x64 ; push rbx ; xor edi, edi // recv ; mov rbx, [rsi + 8] // save data array pointer to non-volatile register ; mov rax, QWORD 0 ; call rax ; mov [rbx], rax // copy return value to data pointer address ; pop rbx ; ret ); let expected = assembler.finalize().unwrap(); assert_eq!(trampoline.0.deref(), expected.deref()); }
#[test] fn return_u64_in_stack_typed_array() { let trampoline = SysVAmd64::compile(&symbol( vec![U64, U64, U64, U64, U64, U64, U64], U64, ));
let mut assembler = dynasmrt::x64::Assembler::new().unwrap(); // See https://godbolt.org/z/cPnPYWdWq dynasm!(assembler ; .arch x64 ; push rbx ; sub rsp, DWORD 16 ; mov rdi, rsi // u64 ; mov rsi, rdx // u64 ; mov rdx, rcx // u64 ; mov rcx, r8 // u64 ; mov r8, r9 // u64 ; mov r9, [DWORD rsp + 32] // u64 ; mov rax, [DWORD rsp + 40] // u64 ; mov [DWORD rsp + 0], rax // .. ; mov rax, [DWORD rsp + 48] // save data array pointer to non-volatile register ; mov rbx, [rax + 8] // .. ; mov rax, QWORD 0 ; call rax ; mov [rbx], rax // copy return value to data pointer address ; add rsp, DWORD 16 ; pop rbx ; ret ); let expected = assembler.finalize().unwrap(); assert_eq!(trampoline.0.deref(), expected.deref()); } }
mod aarch64_apple { use std::ops::Deref;
use dynasmrt::dynasm;
use super::super::Aarch64Apple; use super::symbol; use crate::NativeType::*;
#[test] fn tailcall() { let trampoline = Aarch64Apple::compile(&symbol( vec![ U8, U16, I16, I8, U32, U64, Buffer, Function, I64, I32, I16, I8, F32, F32, F32, F32, F64, F64, F64, F64, F32, F64, ], Void, ));
let mut assembler = dynasmrt::aarch64::Assembler::new().unwrap(); // See https://godbolt.org/z/oefqYWT13 dynasm!(assembler ; .arch aarch64 ; and w0, w1, 0xFF // u8 ; and w1, w2, 0xFFFF // u16 ; sxth w2, w3 // i16 ; sxtb w3, w4 // i8 ; mov w4, w5 // u32 ; mov x5, x6 // u64 ; ldr x6, [x7, 8] // Buffer ; ldr x7, [sp] // Function ; ldr x8, [sp, 8] // i64 ; str x8, [sp] // .. ; ldr w8, [sp, 16] // i32 ; str w8, [sp, 8] // .. ; ldr w8, [sp, 24] // i16 ; strh w8, [sp, 12] // .. ; ldr w8, [sp, 32] // i8 ; strb w8, [sp, 14] // .. ; ldr s16, [sp, 40] // f32 ; str s16, [sp, 16] // .. ; ldr d16, [sp, 48] // f64 ; str d16, [sp, 24] // .. ; movz x8, 0 ; br x8 ); let expected = assembler.finalize().unwrap(); assert_eq!(trampoline.0.deref(), expected.deref()); }
#[test] fn integer_casting() { let trampoline = Aarch64Apple::compile(&symbol( vec![U8, U16, I8, I16, U8, U16, I8, I16, U8, U16, I8, I16], I8, ));
let mut assembler = dynasmrt::aarch64::Assembler::new().unwrap(); // See https://godbolt.org/z/7qfzbzobM dynasm!(assembler ; .arch aarch64 ; and w0, w1, 0xFF // u8 ; and w1, w2, 0xFFFF // u16 ; sxtb w2, w3 // i8 ; sxth w3, w4 // i16 ; and w4, w5, 0xFF // u8 ; and w5, w6, 0xFFFF // u16 ; sxtb w6, w7 // i8 ; ldrsh w7, [sp] // i16 ; ldr w8, [sp, 8] // u8 ; strb w8, [sp] // .. ; ldr w8, [sp, 16] // u16 ; strh w8, [sp, 2] // .. ; ldr w8, [sp, 24] // i8 ; strb w8, [sp, 4] // .. ; ldr w8, [sp, 32] // i16 ; strh w8, [sp, 6] // .. ; movz x8, 0 ; br x8 ); let expected = assembler.finalize().unwrap(); assert_eq!(trampoline.0.deref(), expected.deref()); }
#[test] fn buffer_parameters() { let trampoline = Aarch64Apple::compile(&symbol( vec![ Buffer, Buffer, Buffer, Buffer, Buffer, Buffer, Buffer, Buffer, Buffer, Buffer, ], Void, ));
let mut assembler = dynasmrt::aarch64::Assembler::new().unwrap(); // See https://godbolt.org/z/obd6z6vsf dynasm!(assembler ; .arch aarch64 ; ldr x0, [x1, 8] // Buffer ; ldr x1, [x2, 8] // Buffer ; ldr x2, [x3, 8] // Buffer ; ldr x3, [x4, 8] // Buffer ; ldr x4, [x5, 8] // Buffer ; ldr x5, [x6, 8] // Buffer ; ldr x6, [x7, 8] // Buffer ; ldr x7, [sp] // Buffer ; ldr x7, [x7, 8] // .. ; ldr x8, [sp, 8] // Buffer ; ldr x8, [x8, 8] // .. ; str x8, [sp] // .. ; ldr x8, [sp, 16] // Buffer ; ldr x8, [x8, 8] // .. ; str x8, [sp, 8] // .. ; movz x8, 0 ; br x8 ); let expected = assembler.finalize().unwrap(); assert_eq!(trampoline.0.deref(), expected.deref()); }
#[test] fn return_u64_in_register_typed_array() { let trampoline = Aarch64Apple::compile(&symbol(vec![], U64));
let mut assembler = dynasmrt::aarch64::Assembler::new().unwrap(); // See https://godbolt.org/z/47EvvYb83 dynasm!(assembler ; .arch aarch64 ; sub sp, sp, 32 ; stp x29, x30, [sp, 16] ; add x29, sp, 16 ; str x19, [sp, 8] ; mov x0, xzr // recv ; ldr x19, [x1, 8] // save data array pointer to non-volatile register ; movz x8, 0 ; blr x8 ; str x0, [x19] // copy return value to data pointer address ; ldr x19, [sp, 8] ; ldp x29, x30, [sp, 16] ; add sp, sp, 32 ; ret ); let expected = assembler.finalize().unwrap(); assert_eq!(trampoline.0.deref(), expected.deref()); }
#[test] fn return_u64_in_stack_typed_array() { let trampoline = Aarch64Apple::compile(&symbol( vec![U64, U64, U64, U64, U64, U64, U64, U64, U8, U8], U64, ));
let mut assembler = dynasmrt::aarch64::Assembler::new().unwrap(); // See https://godbolt.org/z/PvYPbsE1b dynasm!(assembler ; .arch aarch64 ; sub sp, sp, 32 ; stp x29, x30, [sp, 16] ; add x29, sp, 16 ; str x19, [sp, 8] ; mov x0, x1 // u64 ; mov x1, x2 // u64 ; mov x2, x3 // u64 ; mov x3, x4 // u64 ; mov x4, x5 // u64 ; mov x5, x6 // u64 ; mov x6, x7 // u64 ; ldr x7, [sp, 32] // u64 ; ldr w8, [sp, 40] // u8 ; strb w8, [sp] // .. ; ldr w8, [sp, 48] // u8 ; strb w8, [sp, 1] // .. ; ldr x19, [sp, 56] // save data array pointer to non-volatile register ; ldr x19, [x19, 8] // .. ; movz x8, 0 ; blr x8 ; str x0, [x19] // copy return value to data pointer address ; ldr x19, [sp, 8] ; ldp x29, x30, [sp, 16] ; add sp, sp, 32 ; ret ); let expected = assembler.finalize().unwrap(); assert_eq!(trampoline.0.deref(), expected.deref()); } }
mod x64_windows { use std::ops::Deref;
use dynasmrt::{dynasm, DynasmApi};
use super::super::Win64; use super::symbol; use crate::NativeType::*;
#[test] fn tailcall() { let trampoline = Win64::compile(&symbol(vec![U8, I16, F64, F32, U32, I8, Buffer], Void));
let mut assembler = dynasmrt::x64::Assembler::new().unwrap(); // See https://godbolt.org/z/TYzqrf9aj dynasm!(assembler ; .arch x64 ; mov ecx, edx // u8 ; mov edx, r8d // i16 ; movaps xmm2, xmm3 // f64 ; movaps xmm3, [DWORD rsp + 40] // f32 ; mov eax, [DWORD rsp + 48] // u32 ; mov [DWORD rsp + 40], eax // .. ; mov eax, [DWORD rsp + 56] // i8 ; mov [DWORD rsp + 48], eax // .. ; mov rax, [DWORD rsp + 64] // Buffer ; mov rax, [rax + 8] // .. ; mov [DWORD rsp + 56], rax // .. ; mov rax, QWORD 0 ; jmp rax ); let expected = assembler.finalize().unwrap(); assert_eq!(trampoline.0.deref(), expected.deref()); }
#[test] fn integer_casting() { let trampoline = Win64::compile(&symbol( vec![U8, U16, I8, I16, U8, U16, I8, I16, U8, U16, I8, I16], I8, ));
let mut assembler = dynasmrt::x64::Assembler::new().unwrap(); // See https://godbolt.org/z/KMx56KGTq dynasm!(assembler ; .arch x64 ; sub rsp, DWORD 104 // stack allocation ; mov ecx, edx // u8 ; mov edx, r8d // u16 ; mov r8d, r9d // i8 ; mov r9d, [DWORD rsp + 144] // i16 ; mov eax, [DWORD rsp + 152] // u8 ; mov [DWORD rsp + 32], eax // .. ; mov eax, [DWORD rsp + 160] // u16 ; mov [DWORD rsp + 40], eax // u16 ; mov eax, [DWORD rsp + 168] // i8 ; mov [DWORD rsp + 48], eax // .. ; mov eax, [DWORD rsp + 176] // i16 ; mov [DWORD rsp + 56], eax // .. ; mov eax, [DWORD rsp + 184] // u8 ; mov [DWORD rsp + 64], eax // .. ; mov eax, [DWORD rsp + 192] // u16 ; mov [DWORD rsp + 72], eax // .. ; mov eax, [DWORD rsp + 200] // i8 ; mov [DWORD rsp + 80], eax // .. ; mov eax, [DWORD rsp + 208] // i16 ; mov [DWORD rsp + 88], eax // .. ; mov rax, QWORD 0 ; call rax ; movsx eax, al // return value cast ; add rsp, DWORD 104 // stack deallocation ; ret ); let expected = assembler.finalize().unwrap(); assert_eq!(trampoline.0.deref(), expected.deref()); }
#[test] fn buffer_parameters() { let trampoline = Win64::compile(&symbol( vec![Buffer, Buffer, Buffer, Buffer, Buffer, Buffer], Void, ));
let mut assembler = dynasmrt::x64::Assembler::new().unwrap(); // See https://godbolt.org/z/TYzqrf9aj dynasm!(assembler ; .arch x64 ; mov rcx, [rdx + 8] // Buffer ; mov rdx, [r8 + 8] // Buffer ; mov r8, [r9 + 8] // Buffer ; mov r9, [DWORD rsp + 40] // Buffer ; mov r9, [r9 + 8] // .. ; mov rax, [DWORD rsp + 48] // Buffer ; mov rax, [rax + 8] // .. ; mov [DWORD rsp + 40], rax // .. ; mov rax, [DWORD rsp + 56] // Buffer ; mov rax, [rax + 8] // .. ; mov [DWORD rsp + 48], rax // .. ; mov rax, QWORD 0 ; jmp rax ); let expected = assembler.finalize().unwrap(); assert_eq!(trampoline.0.deref(), expected.deref()); }
#[test] fn return_u64_in_register_typed_array() { let trampoline = Win64::compile(&symbol(vec![], U64));
let mut assembler = dynasmrt::x64::Assembler::new().unwrap(); // See https://godbolt.org/z/7EnPE7o3T dynasm!(assembler ; .arch x64 ; push rbx ; sub rsp, DWORD 32 ; xor ecx, ecx // recv ; mov rbx, [rdx + 8] // save data array pointer to non-volatile register ; mov rax, QWORD 0 ; call rax ; mov [rbx], rax // copy return value to data pointer address ; add rsp, DWORD 32 ; pop rbx ; ret ); let expected = assembler.finalize().unwrap(); assert_eq!(trampoline.0.deref(), expected.deref()); }
#[test] fn return_u64_in_stack_typed_array() { let trampoline = Win64::compile(&symbol(vec![U64, U64, U64, U64, U64], U64));
let mut assembler = dynasmrt::x64::Assembler::new().unwrap(); // See https://godbolt.org/z/3966sfEex dynasm!(assembler ; .arch x64 ; push rbx ; sub rsp, DWORD 48 ; mov rcx, rdx // u64 ; mov rdx, r8 // u64 ; mov r8, r9 // u64 ; mov r9, [DWORD rsp + 96] // u64 ; mov rax, [DWORD rsp + 104] // u64 ; mov [DWORD rsp + 32], rax // .. ; mov rax, [DWORD rsp + 112] // save data array pointer to non-volatile register ; mov rbx, [rax + 8] // .. ; mov rax, QWORD 0 ; call rax ; mov [rbx], rax // copy return value to data pointer address ; add rsp, DWORD 48 ; pop rbx ; ret ); let expected = assembler.finalize().unwrap(); assert_eq!(trampoline.0.deref(), expected.deref()); } }}
deno
Version Info
a year ago
