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denoland-deno/ext/ffi/jit_trampoline.rs
2022-08-23 09:16:43 +05:30

261 lines
8.1 KiB
Rust

// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
use crate::NativeType;
use crate::{tcc::Compiler, Symbol};
use std::ffi::c_void;
use std::ffi::CString;
use std::fmt::Write as _;
use std::mem::size_of;
const _: () = assert!(size_of::<fn()>() == size_of::<usize>());
pub(crate) struct Allocation {
pub addr: *mut c_void,
_ctx: Compiler,
_sym: Box<Symbol>,
}
macro_rules! cstr {
($st:expr) => {
&CString::new($st).unwrap()
};
}
fn native_arg_to_c(ty: &NativeType) -> &'static str {
match ty {
NativeType::U8 | NativeType::U16 | NativeType::U32 => "uint32_t",
NativeType::I8 | NativeType::I16 | NativeType::I32 => "int32_t",
NativeType::Void => "void",
NativeType::F32 => "float",
NativeType::F64 => "double",
NativeType::U64 => "uint64_t",
NativeType::I64 => "int64_t",
NativeType::ISize => "intptr_t",
NativeType::USize => "uintptr_t",
NativeType::Buffer => "struct FastApiTypedArray*",
NativeType::Function | NativeType::Pointer => "void*",
}
}
fn native_to_c(ty: &NativeType) -> &'static str {
match ty {
NativeType::U8 => "uint8_t",
NativeType::U16 => "uint16_t",
NativeType::U32 => "uint32_t",
NativeType::I8 => "int8_t",
NativeType::I16 => "uint16_t",
NativeType::I32 => "int32_t",
NativeType::Void => "void",
NativeType::F32 => "float",
NativeType::F64 => "double",
NativeType::U64 => "uint64_t",
NativeType::I64 => "int64_t",
NativeType::ISize => "intptr_t",
NativeType::USize => "uintptr_t",
NativeType::Pointer | NativeType::Buffer | NativeType::Function => "void*",
}
}
pub(crate) fn codegen(sym: &crate::Symbol) -> String {
let mut c = String::from(include_str!("prelude.h"));
let needs_unwrap = crate::needs_unwrap(sym.result_type);
// Return type of the FFI call.
let ffi_ret = native_to_c(&sym.result_type);
// Return type of the trampoline.
let ret = if needs_unwrap { "void" } else { ffi_ret };
// extern <return_type> func(
let _ = write!(c, "\nextern {ffi_ret} func(");
// <param_type> p0, <param_type> p1, ...);
for (i, ty) in sym.parameter_types.iter().enumerate() {
if i > 0 {
c += ", ";
}
c += native_to_c(ty);
let _ = write!(c, " p{i}");
}
c += ");\n\n";
// void* recv, <param_type> p0, <param_type> p1, ...);
c += ret;
c += " func_trampoline(";
c += "void* recv";
for (i, ty) in sym.parameter_types.iter().enumerate() {
c += ", ";
c += native_arg_to_c(ty);
let _ = write!(c, " p{i}");
}
if needs_unwrap {
let _ = write!(c, ", struct FastApiTypedArray* const p_ret");
}
c += ") {\n";
// func(p0, p1, ...);
let mut call_s = String::from("func(");
{
for (i, ty) in sym.parameter_types.iter().enumerate() {
if i > 0 {
call_s += ", ";
}
if matches!(ty, NativeType::Buffer) {
let _ = write!(call_s, "p{i}->data");
} else {
let _ = write!(call_s, "p{i}");
}
}
call_s += ");\n";
}
if needs_unwrap {
// <return_type> r = func(p0, p1, ...);
// ((<return_type>*)p_ret->data)[0] = r;
let _ = write!(c, " {ffi_ret} r = {call_s}");
let _ = writeln!(c, " (({ffi_ret}*)p_ret->data)[0] = r;");
} else {
// return func(p0, p1, ...);
let _ = write!(c, " return {call_s}");
}
c += "}\n\n";
c
}
pub(crate) fn gen_trampoline(
sym: Box<crate::Symbol>,
) -> Result<Box<Allocation>, ()> {
let mut ctx = Compiler::new()?;
ctx.set_options(cstr!("-nostdlib"));
// SAFETY: symbol satisfies ABI requirement.
unsafe { ctx.add_symbol(cstr!("func"), sym.ptr.0 as *const c_void) };
let c = codegen(&sym);
ctx.compile_string(cstr!(c))?;
let alloc = Allocation {
addr: ctx.relocate_and_get_symbol(cstr!("func_trampoline"))?,
_ctx: ctx,
_sym: sym,
};
Ok(Box::new(alloc))
}
#[cfg(test)]
mod tests {
use super::*;
use libffi::middle::Type;
use std::ptr::null_mut;
fn codegen(parameters: Vec<NativeType>, ret: NativeType) -> String {
let sym = Box::new(crate::Symbol {
cif: libffi::middle::Cif::new(vec![], Type::void()),
ptr: libffi::middle::CodePtr(null_mut()),
parameter_types: parameters,
result_type: ret,
can_callback: false,
});
super::codegen(&sym)
}
const PRELUDE: &str = include_str!("prelude.h");
fn assert_codegen(expected: String, actual: &str) {
assert_eq!(expected, format!("{PRELUDE}\n{}", actual))
}
#[test]
fn test_gen_trampoline() {
assert_codegen(
codegen(vec![], NativeType::Void),
"extern void func();\n\n\
void func_trampoline(void* recv) {\
\n return func();\n\
}\n\n",
);
assert_codegen(
codegen(vec![NativeType::U32, NativeType::U32], NativeType::U32),
"extern uint32_t func(uint32_t p0, uint32_t p1);\n\n\
uint32_t func_trampoline(void* recv, uint32_t p0, uint32_t p1) {\
\n return func(p0, p1);\n\
}\n\n",
);
assert_codegen(
codegen(vec![NativeType::I32, NativeType::I32], NativeType::I32),
"extern int32_t func(int32_t p0, int32_t p1);\n\n\
int32_t func_trampoline(void* recv, int32_t p0, int32_t p1) {\
\n return func(p0, p1);\n\
}\n\n",
);
assert_codegen(
codegen(vec![NativeType::F32, NativeType::F32], NativeType::F32),
"extern float func(float p0, float p1);\n\n\
float func_trampoline(void* recv, float p0, float p1) {\
\n return func(p0, p1);\n\
}\n\n",
);
assert_codegen(
codegen(vec![NativeType::F64, NativeType::F64], NativeType::F64),
"extern double func(double p0, double p1);\n\n\
double func_trampoline(void* recv, double p0, double p1) {\
\n return func(p0, p1);\n\
}\n\n",
);
assert_codegen(
codegen(vec![NativeType::Buffer, NativeType::U32], NativeType::U32),
"extern uint32_t func(void* p0, uint32_t p1);\n\n\
uint32_t func_trampoline(void* recv, struct FastApiTypedArray* p0, uint32_t p1) {\
\n return func(p0->data, p1);\n\
}\n\n",
);
assert_codegen(
codegen(vec![NativeType::Buffer, NativeType::Buffer], NativeType::U32),
"extern uint32_t func(void* p0, void* p1);\n\n\
uint32_t func_trampoline(void* recv, struct FastApiTypedArray* p0, struct FastApiTypedArray* p1) {\
\n return func(p0->data, p1->data);\n\
}\n\n",
);
assert_codegen(
codegen(vec![], NativeType::U64),
"extern uint64_t func();\n\n\
void func_trampoline(void* recv, struct FastApiTypedArray* const p_ret) {\
\n uint64_t r = func();\
\n ((uint64_t*)p_ret->data)[0] = r;\n\
}\n\n",
);
assert_codegen(
codegen(vec![NativeType::Buffer, NativeType::Buffer], NativeType::U64),
"extern uint64_t func(void* p0, void* p1);\n\n\
void func_trampoline(void* recv, struct FastApiTypedArray* p0, struct FastApiTypedArray* p1, struct FastApiTypedArray* const p_ret) {\
\n uint64_t r = func(p0->data, p1->data);\
\n ((uint64_t*)p_ret->data)[0] = r;\n\
}\n\n",
);
assert_codegen(
codegen(vec![NativeType::Pointer, NativeType::Pointer], NativeType::U64),
"extern uint64_t func(void* p0, void* p1);\n\n\
void func_trampoline(void* recv, void* p0, void* p1, struct FastApiTypedArray* const p_ret) {\
\n uint64_t r = func(p0, p1);\
\n ((uint64_t*)p_ret->data)[0] = r;\n\
}\n\n",
);
}
#[test]
fn test_gen_trampoline_implicit_cast() {
assert_codegen(
codegen(vec![NativeType::I8, NativeType::U8], NativeType::I8),
"extern int8_t func(int8_t p0, uint8_t p1);\n\n\
int8_t func_trampoline(void* recv, int32_t p0, uint32_t p1) {\
\n return func(p0, p1);\n\
}\n\n",
);
assert_codegen(
codegen(vec![NativeType::ISize, NativeType::U64], NativeType::Void),
"extern void func(intptr_t p0, uint64_t p1);\n\n\
void func_trampoline(void* recv, intptr_t p0, uint64_t p1) {\
\n return func(p0, p1);\n\
}\n\n",
);
assert_codegen(
codegen(vec![NativeType::USize, NativeType::USize], NativeType::U32),
"extern uint32_t func(uintptr_t p0, uintptr_t p1);\n\n\
uint32_t func_trampoline(void* recv, uintptr_t p0, uintptr_t p1) {\
\n return func(p0, p1);\n\
}\n\n",
);
}
}