src/runtime/mkpreempt.go - go - Git at Google

 // Copyright 2019 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.

 // +build ignore

 // mkpreempt generates the asyncPreempt functions for each
 // architecture.
 package main

 import (
 	"flag"
 	"fmt"
 	"io"
 	"log"
 	"os"
 	"strings"
 )

 // Copied from cmd/compile/internal/ssa/gen/*Ops.go

 var regNames386 = []string{
 	"AX",
 	"CX",
 	"DX",
 	"BX",
 	"SP",
 	"BP",
 	"SI",
 	"DI",
 	"X0",
 	"X1",
 	"X2",
 	"X3",
 	"X4",
 	"X5",
 	"X6",
 	"X7",
 }

 var regNamesAMD64 = []string{
 	"AX",
 	"CX",
 	"DX",
 	"BX",
 	"SP",
 	"BP",
 	"SI",
 	"DI",
 	"R8",
 	"R9",
 	"R10",
 	"R11",
 	"R12",
 	"R13",
 	"R14",
 	"R15",
 	"X0",
 	"X1",
 	"X2",
 	"X3",
 	"X4",
 	"X5",
 	"X6",
 	"X7",
 	"X8",
 	"X9",
 	"X10",
 	"X11",
 	"X12",
 	"X13",
 	"X14",
 	"X15",
 }

 var out io.Writer

 var arches = map[string]func(){
 	"386":     gen386,
 	"amd64":   genAMD64,
 	"arm":     genARM,
 	"arm64":   notImplemented,
 	"mips64x": notImplemented,
 	"mipsx":   notImplemented,
 	"ppc64x":  notImplemented,
 	"s390x":   notImplemented,
 	"wasm":    genWasm,
 }
 var beLe = map[string]bool{"mips64x": true, "mipsx": true, "ppc64x": true}

 func main() {
 	flag.Parse()
 	if flag.NArg() > 0 {
 		out = os.Stdout
 		for _, arch := range flag.Args() {
 			gen, ok := arches[arch]
 			if !ok {
 				log.Fatalf("unknown arch %s", arch)
 			}
 			header(arch)
 			gen()
 		}
 		return
 	}

 	for arch, gen := range arches {
 		f, err := os.Create(fmt.Sprintf("preempt_%s.s", arch))
 		if err != nil {
 			log.Fatal(err)
 		}
 		out = f
 		header(arch)
 		gen()
 		if err := f.Close(); err != nil {
 			log.Fatal(err)
 		}
 	}
 }

 func header(arch string) {
 	fmt.Fprintf(out, "// Code generated by mkpreempt.go; DO NOT EDIT.\n\n")
 	if beLe[arch] {
 		base := arch[:len(arch)-1]
 		fmt.Fprintf(out, "// +build %s %sle\n\n", base, base)
 	}
 	fmt.Fprintf(out, "#include \"go_asm.h\"\n")
 	fmt.Fprintf(out, "#include \"textflag.h\"\n\n")
 	fmt.Fprintf(out, "TEXT ·asyncPreempt(SB),NOSPLIT|NOFRAME,$0-0\n")
 }

 func p(f string, args ...interface{}) {
 	fmted := fmt.Sprintf(f, args...)
 	fmt.Fprintf(out, "\t%s\n", strings.Replace(fmted, "\n", "\n\t", -1))
 }

 func label(l string) {
 	fmt.Fprintf(out, "%s\n", l)
 }

 type layout struct {
 	stack int
 	regs  []regPos
 	sp    string // stack pointer register
 }

 type regPos struct {
 	pos int

 	op  string
 	reg string

 	// If this register requires special save and restore, these
 	// give those operations with a %d placeholder for the stack
 	// offset.
 	save, restore string
 }

 func (l *layout) add(op, reg string, size int) {
 	l.regs = append(l.regs, regPos{op: op, reg: reg, pos: l.stack})
 	l.stack += size
 }

 func (l *layout) addSpecial(save, restore string, size int) {
 	l.regs = append(l.regs, regPos{save: save, restore: restore, pos: l.stack})
 	l.stack += size
 }

 func (l *layout) save() {
 	for _, reg := range l.regs {
 		if reg.save != "" {
 			p(reg.save, reg.pos)
 		} else {
 			p("%s %s, %d(%s)", reg.op, reg.reg, reg.pos, l.sp)
 		}
 	}
 }

 func (l *layout) restore() {
 	for i := len(l.regs) - 1; i >= 0; i-- {
 		reg := l.regs[i]
 		if reg.restore != "" {
 			p(reg.restore, reg.pos)
 		} else {
 			p("%s %d(%s), %s", reg.op, reg.pos, l.sp, reg.reg)
 		}
 	}
 }

 func gen386() {
 	p("PUSHFL")

 	// Save general purpose registers.
 	var l = layout{sp: "SP"}
 	for _, reg := range regNames386 {
 		if reg == "SP" || strings.HasPrefix(reg, "X") {
 			continue
 		}
 		l.add("MOVL", reg, 4)
 	}

 	// Save the 387 state.
 	l.addSpecial(
 		"FSAVE %d(SP)\nFLDCW runtime·controlWord64(SB)",
 		"FRSTOR %d(SP)",
 		108)

 	// Save SSE state only if supported.
 	lSSE := layout{stack: l.stack, sp: "SP"}
 	for i := 0; i < 8; i++ {
 		lSSE.add("MOVUPS", fmt.Sprintf("X%d", i), 16)
 	}

 	p("ADJSP $%d", lSSE.stack)
 	p("NOP SP")
 	l.save()
 	p("CMPB internal∕cpu·X86+const_offsetX86HasSSE2(SB), $1\nJNE nosse")
 	lSSE.save()
 	label("nosse:")
 	p("CALL ·asyncPreempt2(SB)")
 	p("CMPB internal∕cpu·X86+const_offsetX86HasSSE2(SB), $1\nJNE nosse2")
 	lSSE.restore()
 	label("nosse2:")
 	l.restore()
 	p("ADJSP $%d", -lSSE.stack)

 	p("POPFL")
 	p("RET")
 }

 func genAMD64() {
 	// Assign stack offsets.
 	var l = layout{sp: "SP"}
 	for _, reg := range regNamesAMD64 {
 		if reg == "SP" || reg == "BP" {
 			continue
 		}
 		if strings.HasPrefix(reg, "X") {
 			l.add("MOVUPS", reg, 16)
 		} else {
 			l.add("MOVQ", reg, 8)
 		}
 	}

 	// TODO: MXCSR register?

 	p("PUSHQ BP")
 	p("MOVQ SP, BP")
 	p("// Save flags before clobbering them")
 	p("PUSHFQ")
 	p("// obj doesn't understand ADD/SUB on SP, but does understand ADJSP")
 	p("ADJSP $%d", l.stack)
 	p("// But vet doesn't know ADJSP, so suppress vet stack checking")
 	p("NOP SP")
 	l.save()
 	p("CALL ·asyncPreempt2(SB)")
 	l.restore()
 	p("ADJSP $%d", -l.stack)
 	p("POPFQ")
 	p("POPQ BP")
 	p("RET")
 }

 func genARM() {
 	// Add integer registers R0-R12.
 	// R13 (SP), R14 (LR), R15 (PC) are special and not saved here.
 	var l = layout{sp: "R13", stack: 4} // add LR slot
 	for i := 0; i <= 12; i++ {
 		reg := fmt.Sprintf("R%d", i)
 		if i == 10 {
 			continue // R10 is g register, no need to save/restore
 		}
 		l.add("MOVW", reg, 4)
 	}
 	// Add flag register.
 	l.addSpecial(
 		"MOVW CPSR, R0\nMOVW R0, %d(R13)",
 		"MOVW %d(R13), R0\nMOVW R0, CPSR",
 		4)

 	// Add floating point registers F0-F15 and flag register.
 	var lfp = layout{stack: l.stack, sp: "R13"}
 	lfp.addSpecial(
 		"MOVW FPCR, R0\nMOVW R0, %d(R13)",
 		"MOVW %d(R13), R0\nMOVW R0, FPCR",
 		4)
 	for i := 0; i <= 15; i++ {
 		reg := fmt.Sprintf("F%d", i)
 		lfp.add("MOVD", reg, 8)
 	}

 	p("MOVW.W R14, -%d(R13)", lfp.stack) // allocate frame, save LR
 	l.save()
 	p("MOVB ·goarm(SB), R0\nCMP $6, R0\nBLT nofp") // test goarm, and skip FP registers if goarm=5.
 	lfp.save()
 	label("nofp:")
 	p("CALL ·asyncPreempt2(SB)")
 	p("MOVB ·goarm(SB), R0\nCMP $6, R0\nBLT nofp2") // test goarm, and skip FP registers if goarm=5.
 	lfp.restore()
 	label("nofp2:")
 	l.restore()

 	p("MOVW %d(R13), R14", lfp.stack)     // sigctxt.pushCall pushes LR on stack, restore it
 	p("MOVW.P %d(R13), R15", lfp.stack+4) // load PC, pop frame (including the space pushed by sigctxt.pushCall)
 	p("UNDEF")                            // shouldn't get here
 }

 func genWasm() {
 	p("// No async preemption on wasm")
 	p("UNDEF")
 }

 func notImplemented() {
 	p("// Not implemented yet")
 	p("JMP ·abort(SB)")
 }
	// Copyright 2019 The Go Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style
	// license that can be found in the LICENSE file.

	// +build ignore

	// mkpreempt generates the asyncPreempt functions for each
	// architecture.
	package main

	import (
	"flag"
	"fmt"
	"io"
	"log"
	"os"
	"strings"
	)

	// Copied from cmd/compile/internal/ssa/gen/*Ops.go

	var regNames386 = []string{
	"AX",
	"CX",
	"DX",
	"BX",
	"SP",
	"BP",
	"SI",
	"DI",
	"X0",
	"X1",
	"X2",
	"X3",
	"X4",
	"X5",
	"X6",
	"X7",
	}

	var regNamesAMD64 = []string{
	"AX",
	"CX",
	"DX",
	"BX",
	"SP",
	"BP",
	"SI",
	"DI",
	"R8",
	"R9",
	"R10",
	"R11",
	"R12",
	"R13",
	"R14",
	"R15",
	"X0",
	"X1",
	"X2",
	"X3",
	"X4",
	"X5",
	"X6",
	"X7",
	"X8",
	"X9",
	"X10",
	"X11",
	"X12",
	"X13",
	"X14",
	"X15",
	}

	var out io.Writer

	var arches = map[string]func(){
	"386": gen386,
	"amd64": genAMD64,
	"arm": genARM,
	"arm64": notImplemented,
	"mips64x": notImplemented,
	"mipsx": notImplemented,
	"ppc64x": notImplemented,
	"s390x": notImplemented,
	"wasm": genWasm,
	}
	var beLe = map[string]bool{"mips64x": true, "mipsx": true, "ppc64x": true}

	func main() {
	flag.Parse()
	if flag.NArg() > 0 {
	out = os.Stdout
	for _, arch := range flag.Args() {
	gen, ok := arches[arch]
	if !ok {
	log.Fatalf("unknown arch %s", arch)
	}
	header(arch)
	gen()
	}
	return
	}

	for arch, gen := range arches {
	f, err := os.Create(fmt.Sprintf("preempt_%s.s", arch))
	if err != nil {
	log.Fatal(err)
	}
	out = f
	header(arch)
	gen()
	if err := f.Close(); err != nil {
	log.Fatal(err)
	}
	}
	}

	func header(arch string) {
	fmt.Fprintf(out, "// Code generated by mkpreempt.go; DO NOT EDIT.\n\n")
	if beLe[arch] {
	base := arch[:len(arch)-1]
	fmt.Fprintf(out, "// +build %s %sle\n\n", base, base)
	}
	fmt.Fprintf(out, "#include \"go_asm.h\"\n")
	fmt.Fprintf(out, "#include \"textflag.h\"\n\n")
	fmt.Fprintf(out, "TEXT ·asyncPreempt(SB),NOSPLIT\|NOFRAME,$0-0\n")
	}

	func p(f string, args ...interface{}) {
	fmted := fmt.Sprintf(f, args...)
	fmt.Fprintf(out, "\t%s\n", strings.Replace(fmted, "\n", "\n\t", -1))
	}

	func label(l string) {
	fmt.Fprintf(out, "%s\n", l)
	}

	type layout struct {
	stack int
	regs []regPos
	sp string // stack pointer register
	}

	type regPos struct {
	pos int

	op string
	reg string

	// If this register requires special save and restore, these
	// give those operations with a %d placeholder for the stack
	// offset.
	save, restore string
	}

	func (l *layout) add(op, reg string, size int) {
	l.regs = append(l.regs, regPos{op: op, reg: reg, pos: l.stack})
	l.stack += size
	}

	func (l *layout) addSpecial(save, restore string, size int) {
	l.regs = append(l.regs, regPos{save: save, restore: restore, pos: l.stack})
	l.stack += size
	}

	func (l *layout) save() {
	for _, reg := range l.regs {
	if reg.save != "" {
	p(reg.save, reg.pos)
	} else {
	p("%s %s, %d(%s)", reg.op, reg.reg, reg.pos, l.sp)
	}
	}
	}

	func (l *layout) restore() {
	for i := len(l.regs) - 1; i >= 0; i-- {
	reg := l.regs[i]
	if reg.restore != "" {
	p(reg.restore, reg.pos)
	} else {
	p("%s %d(%s), %s", reg.op, reg.pos, l.sp, reg.reg)
	}
	}
	}

	func gen386() {
	p("PUSHFL")

	// Save general purpose registers.
	var l = layout{sp: "SP"}
	for _, reg := range regNames386 {
	if reg == "SP" \|\| strings.HasPrefix(reg, "X") {
	continue
	}
	l.add("MOVL", reg, 4)
	}

	// Save the 387 state.
	l.addSpecial(
	"FSAVE %d(SP)\nFLDCW runtime·controlWord64(SB)",
	"FRSTOR %d(SP)",
	108)

	// Save SSE state only if supported.
	lSSE := layout{stack: l.stack, sp: "SP"}
	for i := 0; i < 8; i++ {
	lSSE.add("MOVUPS", fmt.Sprintf("X%d", i), 16)
	}

	p("ADJSP $%d", lSSE.stack)
	p("NOP SP")
	l.save()
	p("CMPB internal∕cpu·X86+const_offsetX86HasSSE2(SB), $1\nJNE nosse")
	lSSE.save()
	label("nosse:")
	p("CALL ·asyncPreempt2(SB)")
	p("CMPB internal∕cpu·X86+const_offsetX86HasSSE2(SB), $1\nJNE nosse2")
	lSSE.restore()
	label("nosse2:")
	l.restore()
	p("ADJSP $%d", -lSSE.stack)

	p("POPFL")
	p("RET")
	}

	func genAMD64() {
	// Assign stack offsets.
	var l = layout{sp: "SP"}
	for _, reg := range regNamesAMD64 {
	if reg == "SP" \|\| reg == "BP" {
	continue
	}
	if strings.HasPrefix(reg, "X") {
	l.add("MOVUPS", reg, 16)
	} else {
	l.add("MOVQ", reg, 8)
	}
	}

	// TODO: MXCSR register?

	p("PUSHQ BP")
	p("MOVQ SP, BP")
	p("// Save flags before clobbering them")
	p("PUSHFQ")
	p("// obj doesn't understand ADD/SUB on SP, but does understand ADJSP")
	p("ADJSP $%d", l.stack)
	p("// But vet doesn't know ADJSP, so suppress vet stack checking")
	p("NOP SP")
	l.save()
	p("CALL ·asyncPreempt2(SB)")
	l.restore()
	p("ADJSP $%d", -l.stack)
	p("POPFQ")
	p("POPQ BP")
	p("RET")
	}

	func genARM() {
	// Add integer registers R0-R12.
	// R13 (SP), R14 (LR), R15 (PC) are special and not saved here.
	var l = layout{sp: "R13", stack: 4} // add LR slot
	for i := 0; i <= 12; i++ {
	reg := fmt.Sprintf("R%d", i)
	if i == 10 {
	continue // R10 is g register, no need to save/restore
	}
	l.add("MOVW", reg, 4)
	}
	// Add flag register.
	l.addSpecial(
	"MOVW CPSR, R0\nMOVW R0, %d(R13)",
	"MOVW %d(R13), R0\nMOVW R0, CPSR",
	4)

	// Add floating point registers F0-F15 and flag register.
	var lfp = layout{stack: l.stack, sp: "R13"}
	lfp.addSpecial(
	"MOVW FPCR, R0\nMOVW R0, %d(R13)",
	"MOVW %d(R13), R0\nMOVW R0, FPCR",
	4)
	for i := 0; i <= 15; i++ {
	reg := fmt.Sprintf("F%d", i)
	lfp.add("MOVD", reg, 8)
	}

	p("MOVW.W R14, -%d(R13)", lfp.stack) // allocate frame, save LR
	l.save()
	p("MOVB ·goarm(SB), R0\nCMP $6, R0\nBLT nofp") // test goarm, and skip FP registers if goarm=5.
	lfp.save()
	label("nofp:")
	p("CALL ·asyncPreempt2(SB)")
	p("MOVB ·goarm(SB), R0\nCMP $6, R0\nBLT nofp2") // test goarm, and skip FP registers if goarm=5.
	lfp.restore()
	label("nofp2:")
	l.restore()

	p("MOVW %d(R13), R14", lfp.stack) // sigctxt.pushCall pushes LR on stack, restore it
	p("MOVW.P %d(R13), R15", lfp.stack+4) // load PC, pop frame (including the space pushed by sigctxt.pushCall)
	p("UNDEF") // shouldn't get here
	}

	func genWasm() {
	p("// No async preemption on wasm")
	p("UNDEF")
	}

	func notImplemented() {
	p("// Not implemented yet")
	p("JMP ·abort(SB)")
	}