9612af466b
Moving settings to a separate config struct has two benefits:
- It decouples the compiler a bit from other packages, most
importantly the compileopts package. Decoupling is generally a good
thing.
- Perhaps more importantly, it precisely specifies which settings are
used while compiling and affect the resulting LLVM module. This will
be necessary for caching the LLVM module.
While it would have been possible to cache without this refactor, it
would have been very easy to miss a setting and thus let the
compiler work with invalid/stale data.
192 строки
6,9 КиБ
Go
192 строки
6,9 КиБ
Go
package compiler
|
|
|
|
// This file implements the syscall.Syscall and syscall.Syscall6 instructions as
|
|
// compiler builtins.
|
|
|
|
import (
|
|
"strconv"
|
|
|
|
"golang.org/x/tools/go/ssa"
|
|
"tinygo.org/x/go-llvm"
|
|
)
|
|
|
|
// createSyscall emits an inline system call instruction, depending on the
|
|
// target OS/arch.
|
|
func (b *builder) createSyscall(call *ssa.CallCommon) (llvm.Value, error) {
|
|
num := b.getValue(call.Args[0])
|
|
var syscallResult llvm.Value
|
|
switch {
|
|
case b.GOARCH == "amd64":
|
|
if b.GOOS == "darwin" {
|
|
// Darwin adds this magic number to system call numbers:
|
|
//
|
|
// > Syscall classes for 64-bit system call entry.
|
|
// > For 64-bit users, the 32-bit syscall number is partitioned
|
|
// > with the high-order bits representing the class and low-order
|
|
// > bits being the syscall number within that class.
|
|
// > The high-order 32-bits of the 64-bit syscall number are unused.
|
|
// > All system classes enter the kernel via the syscall instruction.
|
|
//
|
|
// Source: https://opensource.apple.com/source/xnu/xnu-792.13.8/osfmk/mach/i386/syscall_sw.h
|
|
num = b.CreateOr(num, llvm.ConstInt(b.uintptrType, 0x2000000, false), "")
|
|
}
|
|
// Sources:
|
|
// https://stackoverflow.com/a/2538212
|
|
// https://en.wikibooks.org/wiki/X86_Assembly/Interfacing_with_Linux#syscall
|
|
args := []llvm.Value{num}
|
|
argTypes := []llvm.Type{b.uintptrType}
|
|
// Constraints will look something like:
|
|
// "={rax},0,{rdi},{rsi},{rdx},{r10},{r8},{r9},~{rcx},~{r11}"
|
|
constraints := "={rax},0"
|
|
for i, arg := range call.Args[1:] {
|
|
constraints += "," + [...]string{
|
|
"{rdi}",
|
|
"{rsi}",
|
|
"{rdx}",
|
|
"{r10}",
|
|
"{r8}",
|
|
"{r9}",
|
|
"{r11}",
|
|
"{r12}",
|
|
"{r13}",
|
|
}[i]
|
|
llvmValue := b.getValue(arg)
|
|
args = append(args, llvmValue)
|
|
argTypes = append(argTypes, llvmValue.Type())
|
|
}
|
|
constraints += ",~{rcx},~{r11}"
|
|
fnType := llvm.FunctionType(b.uintptrType, argTypes, false)
|
|
target := llvm.InlineAsm(fnType, "syscall", constraints, true, false, llvm.InlineAsmDialectIntel)
|
|
syscallResult = b.CreateCall(target, args, "")
|
|
case b.GOARCH == "386" && b.GOOS == "linux":
|
|
// Sources:
|
|
// syscall(2) man page
|
|
// https://stackoverflow.com/a/2538212
|
|
// https://en.wikibooks.org/wiki/X86_Assembly/Interfacing_with_Linux#int_0x80
|
|
args := []llvm.Value{num}
|
|
argTypes := []llvm.Type{b.uintptrType}
|
|
// Constraints will look something like:
|
|
// "={eax},0,{ebx},{ecx},{edx},{esi},{edi},{ebp}"
|
|
constraints := "={eax},0"
|
|
for i, arg := range call.Args[1:] {
|
|
constraints += "," + [...]string{
|
|
"{ebx}",
|
|
"{ecx}",
|
|
"{edx}",
|
|
"{esi}",
|
|
"{edi}",
|
|
"{ebp}",
|
|
}[i]
|
|
llvmValue := b.getValue(arg)
|
|
args = append(args, llvmValue)
|
|
argTypes = append(argTypes, llvmValue.Type())
|
|
}
|
|
fnType := llvm.FunctionType(b.uintptrType, argTypes, false)
|
|
target := llvm.InlineAsm(fnType, "int 0x80", constraints, true, false, llvm.InlineAsmDialectIntel)
|
|
syscallResult = b.CreateCall(target, args, "")
|
|
case b.GOARCH == "arm" && b.GOOS == "linux":
|
|
// Implement the EABI system call convention for Linux.
|
|
// Source: syscall(2) man page.
|
|
args := []llvm.Value{}
|
|
argTypes := []llvm.Type{}
|
|
// Constraints will look something like:
|
|
// ={r0},0,{r1},{r2},{r7},~{r3}
|
|
constraints := "={r0}"
|
|
for i, arg := range call.Args[1:] {
|
|
constraints += "," + [...]string{
|
|
"0", // tie to output
|
|
"{r1}",
|
|
"{r2}",
|
|
"{r3}",
|
|
"{r4}",
|
|
"{r5}",
|
|
"{r6}",
|
|
}[i]
|
|
llvmValue := b.getValue(arg)
|
|
args = append(args, llvmValue)
|
|
argTypes = append(argTypes, llvmValue.Type())
|
|
}
|
|
args = append(args, num)
|
|
argTypes = append(argTypes, b.uintptrType)
|
|
constraints += ",{r7}" // syscall number
|
|
for i := len(call.Args) - 1; i < 4; i++ {
|
|
// r0-r3 get clobbered after the syscall returns
|
|
constraints += ",~{r" + strconv.Itoa(i) + "}"
|
|
}
|
|
fnType := llvm.FunctionType(b.uintptrType, argTypes, false)
|
|
target := llvm.InlineAsm(fnType, "svc #0", constraints, true, false, 0)
|
|
syscallResult = b.CreateCall(target, args, "")
|
|
case b.GOARCH == "arm64" && b.GOOS == "linux":
|
|
// Source: syscall(2) man page.
|
|
args := []llvm.Value{}
|
|
argTypes := []llvm.Type{}
|
|
// Constraints will look something like:
|
|
// ={x0},0,{x1},{x2},{x8},~{x3},~{x4},~{x5},~{x6},~{x7},~{x16},~{x17}
|
|
constraints := "={x0}"
|
|
for i, arg := range call.Args[1:] {
|
|
constraints += "," + [...]string{
|
|
"0", // tie to output
|
|
"{x1}",
|
|
"{x2}",
|
|
"{x3}",
|
|
"{x4}",
|
|
"{x5}",
|
|
}[i]
|
|
llvmValue := b.getValue(arg)
|
|
args = append(args, llvmValue)
|
|
argTypes = append(argTypes, llvmValue.Type())
|
|
}
|
|
args = append(args, num)
|
|
argTypes = append(argTypes, b.uintptrType)
|
|
constraints += ",{x8}" // syscall number
|
|
for i := len(call.Args) - 1; i < 8; i++ {
|
|
// x0-x7 may get clobbered during the syscall following the aarch64
|
|
// calling convention.
|
|
constraints += ",~{x" + strconv.Itoa(i) + "}"
|
|
}
|
|
constraints += ",~{x16},~{x17}" // scratch registers
|
|
fnType := llvm.FunctionType(b.uintptrType, argTypes, false)
|
|
target := llvm.InlineAsm(fnType, "svc #0", constraints, true, false, 0)
|
|
syscallResult = b.CreateCall(target, args, "")
|
|
default:
|
|
return llvm.Value{}, b.makeError(call.Pos(), "unknown GOOS/GOARCH for syscall: "+b.GOOS+"/"+b.GOARCH)
|
|
}
|
|
switch b.GOOS {
|
|
case "linux", "freebsd":
|
|
// Return values: r0, r1 uintptr, err Errno
|
|
// Pseudocode:
|
|
// var err uintptr
|
|
// if syscallResult < 0 && syscallResult > -4096 {
|
|
// err = -syscallResult
|
|
// }
|
|
// return syscallResult, 0, err
|
|
zero := llvm.ConstInt(b.uintptrType, 0, false)
|
|
inrange1 := b.CreateICmp(llvm.IntSLT, syscallResult, llvm.ConstInt(b.uintptrType, 0, false), "")
|
|
inrange2 := b.CreateICmp(llvm.IntSGT, syscallResult, llvm.ConstInt(b.uintptrType, 0xfffffffffffff000, true), "") // -4096
|
|
hasError := b.CreateAnd(inrange1, inrange2, "")
|
|
errResult := b.CreateSelect(hasError, b.CreateSub(zero, syscallResult, ""), zero, "syscallError")
|
|
retval := llvm.Undef(b.ctx.StructType([]llvm.Type{b.uintptrType, b.uintptrType, b.uintptrType}, false))
|
|
retval = b.CreateInsertValue(retval, syscallResult, 0, "")
|
|
retval = b.CreateInsertValue(retval, zero, 1, "")
|
|
retval = b.CreateInsertValue(retval, errResult, 2, "")
|
|
return retval, nil
|
|
case "darwin":
|
|
// Return values: r0, r1 uintptr, err Errno
|
|
// Pseudocode:
|
|
// var err uintptr
|
|
// if syscallResult != 0 {
|
|
// err = syscallResult
|
|
// }
|
|
// return syscallResult, 0, err
|
|
zero := llvm.ConstInt(b.uintptrType, 0, false)
|
|
hasError := b.CreateICmp(llvm.IntNE, syscallResult, llvm.ConstInt(b.uintptrType, 0, false), "")
|
|
errResult := b.CreateSelect(hasError, syscallResult, zero, "syscallError")
|
|
retval := llvm.Undef(b.ctx.StructType([]llvm.Type{b.uintptrType, b.uintptrType, b.uintptrType}, false))
|
|
retval = b.CreateInsertValue(retval, syscallResult, 0, "")
|
|
retval = b.CreateInsertValue(retval, zero, 1, "")
|
|
retval = b.CreateInsertValue(retval, errResult, 2, "")
|
|
return retval, nil
|
|
default:
|
|
return llvm.Value{}, b.makeError(call.Pos(), "unknown GOOS/GOARCH for syscall: "+b.GOOS+"/"+b.GOARCH)
|
|
}
|
|
}
|