79467baf12
FreeBSD support has been broken for a long time, probably since https://github.com/tinygo-org/tinygo/pull/1860 (merged in May). Nobody has complained yet, so I am going to assume nobody uses it. This doesn't remove support for FreeBSD entirely: the code necessary to build TinyGo on FreeBSD is still there. It just removes the code necessary to build binaries targetting FreeBSD. But again, it could very well be broken as we don't test it. If anybody wants to re-enable support for FreeBSD, they would be welcome to do that. But I think it would at the very least need a smoke test of some sort.
269 строки
10 КиБ
Go
269 строки
10 КиБ
Go
package compiler
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// This file implements the syscall.Syscall and syscall.Syscall6 instructions as
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// compiler builtins.
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import (
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"strconv"
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"golang.org/x/tools/go/ssa"
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"tinygo.org/x/go-llvm"
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)
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// createRawSyscall creates a system call with the provided system call number
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// and returns the result as a single integer (the system call result). The
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// result is not further interpreted.
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func (b *builder) createRawSyscall(call *ssa.CallCommon) (llvm.Value, error) {
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num := b.getValue(call.Args[0])
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switch {
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case b.GOARCH == "amd64":
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if b.GOOS == "darwin" {
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// Darwin adds this magic number to system call numbers:
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//
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// > Syscall classes for 64-bit system call entry.
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// > For 64-bit users, the 32-bit syscall number is partitioned
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// > with the high-order bits representing the class and low-order
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// > bits being the syscall number within that class.
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// > The high-order 32-bits of the 64-bit syscall number are unused.
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// > All system classes enter the kernel via the syscall instruction.
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//
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// Source: https://opensource.apple.com/source/xnu/xnu-792.13.8/osfmk/mach/i386/syscall_sw.h
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num = b.CreateOr(num, llvm.ConstInt(b.uintptrType, 0x2000000, false), "")
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}
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// Sources:
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// https://stackoverflow.com/a/2538212
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// https://en.wikibooks.org/wiki/X86_Assembly/Interfacing_with_Linux#syscall
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args := []llvm.Value{num}
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argTypes := []llvm.Type{b.uintptrType}
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// Constraints will look something like:
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// "={rax},0,{rdi},{rsi},{rdx},{r10},{r8},{r9},~{rcx},~{r11}"
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constraints := "={rax},0"
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for i, arg := range call.Args[1:] {
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constraints += "," + [...]string{
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"{rdi}",
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"{rsi}",
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"{rdx}",
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"{r10}",
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"{r8}",
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"{r9}",
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"{r11}",
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"{r12}",
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"{r13}",
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}[i]
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llvmValue := b.getValue(arg)
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args = append(args, llvmValue)
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argTypes = append(argTypes, llvmValue.Type())
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}
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constraints += ",~{rcx},~{r11}"
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fnType := llvm.FunctionType(b.uintptrType, argTypes, false)
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target := llvm.InlineAsm(fnType, "syscall", constraints, true, false, llvm.InlineAsmDialectIntel)
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return b.CreateCall(target, args, ""), nil
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case b.GOARCH == "386" && b.GOOS == "linux":
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// Sources:
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// syscall(2) man page
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// https://stackoverflow.com/a/2538212
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// https://en.wikibooks.org/wiki/X86_Assembly/Interfacing_with_Linux#int_0x80
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args := []llvm.Value{num}
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argTypes := []llvm.Type{b.uintptrType}
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// Constraints will look something like:
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// "={eax},0,{ebx},{ecx},{edx},{esi},{edi},{ebp}"
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constraints := "={eax},0"
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for i, arg := range call.Args[1:] {
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constraints += "," + [...]string{
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"{ebx}",
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"{ecx}",
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"{edx}",
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"{esi}",
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"{edi}",
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"{ebp}",
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}[i]
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llvmValue := b.getValue(arg)
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args = append(args, llvmValue)
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argTypes = append(argTypes, llvmValue.Type())
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}
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fnType := llvm.FunctionType(b.uintptrType, argTypes, false)
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target := llvm.InlineAsm(fnType, "int 0x80", constraints, true, false, llvm.InlineAsmDialectIntel)
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return b.CreateCall(target, args, ""), nil
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case b.GOARCH == "arm" && b.GOOS == "linux":
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// Implement the EABI system call convention for Linux.
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// Source: syscall(2) man page.
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args := []llvm.Value{}
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argTypes := []llvm.Type{}
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// Constraints will look something like:
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// ={r0},0,{r1},{r2},{r7},~{r3}
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constraints := "={r0}"
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for i, arg := range call.Args[1:] {
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constraints += "," + [...]string{
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"0", // tie to output
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"{r1}",
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"{r2}",
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"{r3}",
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"{r4}",
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"{r5}",
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"{r6}",
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}[i]
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llvmValue := b.getValue(arg)
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args = append(args, llvmValue)
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argTypes = append(argTypes, llvmValue.Type())
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}
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args = append(args, num)
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argTypes = append(argTypes, b.uintptrType)
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constraints += ",{r7}" // syscall number
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for i := len(call.Args) - 1; i < 4; i++ {
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// r0-r3 get clobbered after the syscall returns
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constraints += ",~{r" + strconv.Itoa(i) + "}"
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}
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fnType := llvm.FunctionType(b.uintptrType, argTypes, false)
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target := llvm.InlineAsm(fnType, "svc #0", constraints, true, false, 0)
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return b.CreateCall(target, args, ""), nil
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case b.GOARCH == "arm64" && b.GOOS == "linux":
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// Source: syscall(2) man page.
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args := []llvm.Value{}
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argTypes := []llvm.Type{}
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// Constraints will look something like:
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// ={x0},0,{x1},{x2},{x8},~{x3},~{x4},~{x5},~{x6},~{x7},~{x16},~{x17}
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constraints := "={x0}"
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for i, arg := range call.Args[1:] {
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constraints += "," + [...]string{
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"0", // tie to output
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"{x1}",
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"{x2}",
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"{x3}",
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"{x4}",
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"{x5}",
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}[i]
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llvmValue := b.getValue(arg)
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args = append(args, llvmValue)
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argTypes = append(argTypes, llvmValue.Type())
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}
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args = append(args, num)
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argTypes = append(argTypes, b.uintptrType)
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constraints += ",{x8}" // syscall number
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for i := len(call.Args) - 1; i < 8; i++ {
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// x0-x7 may get clobbered during the syscall following the aarch64
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// calling convention.
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constraints += ",~{x" + strconv.Itoa(i) + "}"
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}
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constraints += ",~{x16},~{x17}" // scratch registers
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fnType := llvm.FunctionType(b.uintptrType, argTypes, false)
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target := llvm.InlineAsm(fnType, "svc #0", constraints, true, false, 0)
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return b.CreateCall(target, args, ""), nil
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default:
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return llvm.Value{}, b.makeError(call.Pos(), "unknown GOOS/GOARCH for syscall: "+b.GOOS+"/"+b.GOARCH)
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}
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}
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// createSyscall emits instructions for the syscall.Syscall* family of
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// functions, depending on the target OS/arch.
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func (b *builder) createSyscall(call *ssa.CallCommon) (llvm.Value, error) {
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switch b.GOOS {
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case "linux":
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syscallResult, err := b.createRawSyscall(call)
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if err != nil {
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return syscallResult, err
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}
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// Return values: r0, r1 uintptr, err Errno
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// Pseudocode:
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// var err uintptr
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// if syscallResult < 0 && syscallResult > -4096 {
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// err = -syscallResult
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// }
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// return syscallResult, 0, err
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zero := llvm.ConstInt(b.uintptrType, 0, false)
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inrange1 := b.CreateICmp(llvm.IntSLT, syscallResult, llvm.ConstInt(b.uintptrType, 0, false), "")
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inrange2 := b.CreateICmp(llvm.IntSGT, syscallResult, llvm.ConstInt(b.uintptrType, 0xfffffffffffff000, true), "") // -4096
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hasError := b.CreateAnd(inrange1, inrange2, "")
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errResult := b.CreateSelect(hasError, b.CreateSub(zero, syscallResult, ""), zero, "syscallError")
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retval := llvm.Undef(b.ctx.StructType([]llvm.Type{b.uintptrType, b.uintptrType, b.uintptrType}, false))
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retval = b.CreateInsertValue(retval, syscallResult, 0, "")
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retval = b.CreateInsertValue(retval, zero, 1, "")
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retval = b.CreateInsertValue(retval, errResult, 2, "")
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return retval, nil
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case "darwin":
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syscallResult, err := b.createRawSyscall(call)
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if err != nil {
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return syscallResult, err
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}
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// Return values: r0, r1 uintptr, err Errno
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// Pseudocode:
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// var err uintptr
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// if syscallResult != 0 {
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// err = syscallResult
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// }
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// return syscallResult, 0, err
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zero := llvm.ConstInt(b.uintptrType, 0, false)
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hasError := b.CreateICmp(llvm.IntNE, syscallResult, llvm.ConstInt(b.uintptrType, 0, false), "")
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errResult := b.CreateSelect(hasError, syscallResult, zero, "syscallError")
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retval := llvm.Undef(b.ctx.StructType([]llvm.Type{b.uintptrType, b.uintptrType, b.uintptrType}, false))
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retval = b.CreateInsertValue(retval, syscallResult, 0, "")
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retval = b.CreateInsertValue(retval, zero, 1, "")
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retval = b.CreateInsertValue(retval, errResult, 2, "")
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return retval, nil
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case "windows":
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// On Windows, syscall.Syscall* is basically just a function pointer
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// call. This is complicated in gc because of stack switching and the
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// different ABI, but easy in TinyGo: just call the function pointer.
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// The signature looks like this:
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// func Syscall(trap, nargs, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno)
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// Prepare input values.
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var paramTypes []llvm.Type
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var params []llvm.Value
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for _, val := range call.Args[2:] {
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param := b.getValue(val)
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params = append(params, param)
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paramTypes = append(paramTypes, param.Type())
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}
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llvmType := llvm.FunctionType(b.uintptrType, paramTypes, false)
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fn := b.getValue(call.Args[0])
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fnPtr := b.CreateIntToPtr(fn, llvm.PointerType(llvmType, 0), "")
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// Prepare some functions that will be called later.
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setLastError := b.mod.NamedFunction("SetLastError")
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if setLastError.IsNil() {
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llvmType := llvm.FunctionType(b.ctx.VoidType(), []llvm.Type{b.ctx.Int32Type()}, false)
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setLastError = llvm.AddFunction(b.mod, "SetLastError", llvmType)
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}
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getLastError := b.mod.NamedFunction("GetLastError")
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if getLastError.IsNil() {
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llvmType := llvm.FunctionType(b.ctx.Int32Type(), nil, false)
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getLastError = llvm.AddFunction(b.mod, "GetLastError", llvmType)
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}
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// Now do the actual call. Pseudocode:
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// SetLastError(0)
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// r1 = trap(a1, a2, a3, ...)
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// err = uintptr(GetLastError())
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// return r1, 0, err
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// Note that SetLastError/GetLastError could be replaced with direct
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// access to the thread control block, which is probably smaller and
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// faster. The Go runtime does this in assembly.
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b.CreateCall(setLastError, []llvm.Value{llvm.ConstNull(b.ctx.Int32Type())}, "")
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syscallResult := b.CreateCall(fnPtr, params, "")
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errResult := b.CreateCall(getLastError, nil, "err")
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if b.uintptrType != b.ctx.Int32Type() {
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errResult = b.CreateZExt(errResult, b.uintptrType, "err.uintptr")
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}
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// Return r1, 0, err
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retval := llvm.ConstNull(b.ctx.StructType([]llvm.Type{b.uintptrType, b.uintptrType, b.uintptrType}, false))
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retval = b.CreateInsertValue(retval, syscallResult, 0, "")
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retval = b.CreateInsertValue(retval, errResult, 2, "")
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return retval, nil
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default:
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return llvm.Value{}, b.makeError(call.Pos(), "unknown GOOS/GOARCH for syscall: "+b.GOOS+"/"+b.GOARCH)
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}
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}
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// createRawSyscallNoError emits instructions for the Linux-specific
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// syscall.rawSyscallNoError function.
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func (b *builder) createRawSyscallNoError(call *ssa.CallCommon) (llvm.Value, error) {
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syscallResult, err := b.createRawSyscall(call)
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if err != nil {
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return syscallResult, err
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}
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retval := llvm.ConstNull(b.ctx.StructType([]llvm.Type{b.uintptrType, b.uintptrType}, false))
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retval = b.CreateInsertValue(retval, syscallResult, 0, "")
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retval = b.CreateInsertValue(retval, llvm.ConstInt(b.uintptrType, 0, false), 1, "")
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return retval, nil
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}
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