go/src/cmd/internal/obj/riscv/asm_test.go
Joel Sing 3c26aef8fb cmd/internal/obj/riscv: improve large branch/call/jump tests
Rework these tests such that they are built on all architectures and
actually executed when run on riscv64. This increases the likelihood
of catching code generation issues, especially those that impact
relocations. Also ensure that the generated assembly includes the
instruction sequence that is expected for the large branch/call/jump.

Change-Id: I15c40a439dd1d0d4ed189ab81697e93d82c4ef4d
Reviewed-on: https://go-review.googlesource.com/c/go/+/721621
Reviewed-by: Mark Ryan <markdryan@rivosinc.com>
Reviewed-by: Mark Freeman <markfreeman@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Junyang Shao <shaojunyang@google.com>
2025-11-21 22:38:02 -08:00

434 lines
12 KiB
Go

// 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.
package riscv
import (
"bytes"
"fmt"
"internal/testenv"
"os"
"os/exec"
"path/filepath"
"regexp"
"runtime"
"testing"
)
// TestLargeBranch generates a large function with a very far conditional
// branch, in order to ensure that it assembles correctly. This requires
// inverting the branch and using a jump to reach the target.
func TestLargeBranch(t *testing.T) {
if testing.Short() {
t.Skip("Skipping test in short mode")
}
testenv.MustHaveGoBuild(t)
dir := t.TempDir()
if err := os.WriteFile(filepath.Join(dir, "go.mod"), []byte("module largecall"), 0644); err != nil {
t.Fatalf("Failed to write file: %v\n", err)
}
main := `package main
import "fmt"
func main() {
fmt.Print(x())
}
func x() uint64
`
if err := os.WriteFile(filepath.Join(dir, "x.go"), []byte(main), 0644); err != nil {
t.Fatalf("failed to write main: %v\n", err)
}
// Generate a very large function.
buf := bytes.NewBuffer(make([]byte, 0, 7000000))
genLargeBranch(buf)
tmpfile := filepath.Join(dir, "x.s")
if err := os.WriteFile(tmpfile, buf.Bytes(), 0644); err != nil {
t.Fatalf("Failed to write file: %v", err)
}
// Assemble generated file.
cmd := exec.Command(testenv.GoToolPath(t), "tool", "asm", "-o", filepath.Join(dir, "x.o"), "-S", tmpfile)
cmd.Env = append(os.Environ(), "GOARCH=riscv64", "GOOS=linux")
out, err := cmd.CombinedOutput()
if err != nil {
t.Errorf("Failed to assemble: %v\n%s", err, out)
}
// The expected instruction sequence for the long branch is:
// BNEZ
// AUIPC $..., X31
// JALR X0, $..., X31
want := regexp.MustCompile(`\sBNEZ\s.*\s.*\n.*\n.*AUIPC\s\$\d+, X31.*\n.*JALR\sX0, \$\d+, ?X31`)
if !want.Match(out) {
t.Error("Missing assembly instructions")
}
// Build generated files.
cmd = testenv.Command(t, testenv.GoToolPath(t), "build", "-o", "x.exe", "-ldflags=-linkmode=internal")
cmd.Dir = dir
cmd.Env = append(os.Environ(), "GOARCH=riscv64", "GOOS=linux")
out, err = cmd.CombinedOutput()
if err != nil {
t.Errorf("Build failed: %v, output: %s", err, out)
}
if runtime.GOARCH == "riscv64" && runtime.GOOS == "linux" {
cmd = testenv.Command(t, filepath.Join(dir, "x.exe"))
out, err = cmd.CombinedOutput()
if err != nil {
t.Errorf("Failed to run test binary: %v", err)
}
if string(out) != "1" {
t.Errorf(`Got test output %q, want "2"`, string(out))
}
}
}
func genLargeBranch(buf *bytes.Buffer) {
fmt.Fprintln(buf, "TEXT ·x(SB),0,$0-8")
fmt.Fprintln(buf, "MOV X0, X10")
fmt.Fprintln(buf, "BEQZ X10, label")
for i := 0; i < 1<<18; i++ {
// Use a non-compressable instruction.
fmt.Fprintln(buf, "ADD $0, X5, X0")
}
fmt.Fprintln(buf, "ADD $1, X10, X10")
fmt.Fprintln(buf, "label:")
fmt.Fprintln(buf, "ADD $1, X10, X10")
fmt.Fprintln(buf, "MOV X10, r+0(FP)")
fmt.Fprintln(buf, "RET")
}
// TestLargeCall generates a large function (>1MB of text) with a call to
// a following function, in order to ensure that it assembles and links
// correctly. This requires the use of AUIPC+JALR instruction sequences,
// which are fixed up by the linker.
func TestLargeCall(t *testing.T) {
if testing.Short() {
t.Skip("Skipping test in short mode")
}
testenv.MustHaveGoBuild(t)
dir := t.TempDir()
if err := os.WriteFile(filepath.Join(dir, "go.mod"), []byte("module largecall"), 0644); err != nil {
t.Fatalf("Failed to write file: %v\n", err)
}
main := `package main
import "fmt"
func main() {
fmt.Print(x())
}
func x() uint64
func y() uint64
`
if err := os.WriteFile(filepath.Join(dir, "x.go"), []byte(main), 0644); err != nil {
t.Fatalf("failed to write main: %v\n", err)
}
// Generate a very large function with call.
buf := bytes.NewBuffer(make([]byte, 0, 7000000))
genLargeCall(buf)
tmpfile := filepath.Join(dir, "x.s")
if err := os.WriteFile(tmpfile, buf.Bytes(), 0644); err != nil {
t.Fatalf("Failed to write file: %v\n", err)
}
// Assemble generated file.
cmd := exec.Command(testenv.GoToolPath(t), "tool", "asm", "-o", filepath.Join(dir, "x.o"), "-S", tmpfile)
cmd.Env = append(os.Environ(), "GOARCH=riscv64", "GOOS=linux")
out, err := cmd.CombinedOutput()
if err != nil {
t.Errorf("Failed to assemble: %v\n%s", err, out)
}
// The expected instruction sequence for the long call is:
// AUIPC $0, $0, X31
// JALR X.., X31
want := regexp.MustCompile(`\sAUIPC\s\$0, \$0, X31.*\n.*\sJALR\sX.*, X31`)
if !want.Match(out) {
t.Error("Missing assembly instructions")
}
// Build generated files.
cmd = testenv.Command(t, testenv.GoToolPath(t), "build", "-o", "x.exe", "-ldflags=-linkmode=internal")
cmd.Dir = dir
cmd.Env = append(os.Environ(), "GOARCH=riscv64", "GOOS=linux")
out, err = cmd.CombinedOutput()
if err != nil {
t.Errorf("Build failed: %v, output: %s", err, out)
}
if runtime.GOARCH == "riscv64" && runtime.GOOS == "linux" {
cmd = testenv.Command(t, filepath.Join(dir, "x.exe"))
out, err = cmd.CombinedOutput()
if err != nil {
t.Errorf("Failed to run test binary: %v", err)
}
if string(out) != "2" {
t.Errorf(`Got test output %q, want "2"`, string(out))
}
}
if runtime.GOARCH == "riscv64" && testenv.HasCGO() {
cmd := testenv.Command(t, testenv.GoToolPath(t), "build", "-o", "x.exe", "-ldflags=-linkmode=external")
cmd.Dir = dir
cmd.Env = append(os.Environ(), "GOARCH=riscv64", "GOOS=linux")
out, err := cmd.CombinedOutput()
if err != nil {
t.Errorf("Build failed: %v, output: %s", err, out)
}
if runtime.GOARCH == "riscv64" && runtime.GOOS == "linux" {
cmd = testenv.Command(t, filepath.Join(dir, "x.exe"))
out, err = cmd.CombinedOutput()
if err != nil {
t.Errorf("Failed to run test binary: %v", err)
}
if string(out) != "2" {
t.Errorf(`Got test output %q, want "2"`, string(out))
}
}
}
}
func genLargeCall(buf *bytes.Buffer) {
fmt.Fprintln(buf, "TEXT ·x(SB),0,$0-8")
fmt.Fprintln(buf, "MOV X0, X10")
fmt.Fprintln(buf, "CALL ·y(SB)")
fmt.Fprintln(buf, "ADD $1, X10, X10")
fmt.Fprintln(buf, "MOV X10, r+0(FP)")
fmt.Fprintln(buf, "RET")
for i := 0; i < 1<<18; i++ {
// Use a non-compressable instruction.
fmt.Fprintln(buf, "ADD $0, X5, X0")
}
fmt.Fprintln(buf, "ADD $1, X10, X10")
fmt.Fprintln(buf, "RET")
fmt.Fprintln(buf, "TEXT ·y(SB),0,$0-0")
fmt.Fprintln(buf, "ADD $1, X10, X10")
fmt.Fprintln(buf, "RET")
}
// TestLargeJump generates a large jump (>1MB of text) with a JMP to the
// end of the function, in order to ensure that it assembles correctly.
// This requires the use of AUIPC+JALR instruction sequences.
func TestLargeJump(t *testing.T) {
if testing.Short() {
t.Skip("Skipping test in short mode")
}
testenv.MustHaveGoBuild(t)
dir := t.TempDir()
if err := os.WriteFile(filepath.Join(dir, "go.mod"), []byte("module largejump"), 0644); err != nil {
t.Fatalf("Failed to write file: %v\n", err)
}
main := `package main
import "fmt"
func main() {
fmt.Print(x())
}
func x() uint64
`
if err := os.WriteFile(filepath.Join(dir, "x.go"), []byte(main), 0644); err != nil {
t.Fatalf("failed to write main: %v\n", err)
}
// Generate a very large jump instruction.
buf := bytes.NewBuffer(make([]byte, 0, 7000000))
genLargeJump(buf)
tmpfile := filepath.Join(dir, "x.s")
if err := os.WriteFile(tmpfile, buf.Bytes(), 0644); err != nil {
t.Fatalf("Failed to write file: %v\n", err)
}
// Assemble generated file.
cmd := exec.Command(testenv.GoToolPath(t), "tool", "asm", "-o", filepath.Join(dir, "x.o"), "-S", tmpfile)
cmd.Env = append(os.Environ(), "GOARCH=riscv64", "GOOS=linux")
out, err := cmd.CombinedOutput()
if err != nil {
t.Errorf("Failed to assemble: %v\n%s", err, out)
}
// The expected instruction sequence for the long call is:
// AUIPC $..., X31
// JALR X0, $.., X31
want := regexp.MustCompile(`\sAUIPC\s\$\d+, X31.*\n.*\sJALR\sX0, \$\d+, ?X31`)
if !want.Match(out) {
t.Error("Missing assembly instructions")
t.Errorf("%s", out)
}
// Build generated files.
cmd = testenv.Command(t, testenv.GoToolPath(t), "build", "-o", "x.exe")
cmd.Dir = dir
cmd.Env = append(os.Environ(), "GOARCH=riscv64", "GOOS=linux")
out, err = cmd.CombinedOutput()
if err != nil {
t.Errorf("Build failed: %v, output: %s", err, out)
}
if runtime.GOARCH == "riscv64" && runtime.GOOS == "linux" {
cmd = testenv.Command(t, filepath.Join(dir, "x.exe"))
out, err = cmd.CombinedOutput()
if err != nil {
t.Errorf("Failed to run test binary: %v", err)
}
if string(out) != "1" {
t.Errorf(`Got test output %q, want "1"`, string(out))
}
}
}
func genLargeJump(buf *bytes.Buffer) {
fmt.Fprintln(buf, "TEXT ·x(SB),0,$0-8")
fmt.Fprintln(buf, "MOV X0, X10")
fmt.Fprintln(buf, "JMP end")
for i := 0; i < 1<<18; i++ {
// Use a non-compressable instruction.
fmt.Fprintln(buf, "ADD $0, X5, X0")
}
fmt.Fprintln(buf, "ADD $1, X10, X10")
fmt.Fprintln(buf, "end:")
fmt.Fprintln(buf, "ADD $1, X10, X10")
fmt.Fprintln(buf, "MOV X10, r+0(FP)")
fmt.Fprintln(buf, "RET")
}
// Issue 20348.
func TestNoRet(t *testing.T) {
dir := t.TempDir()
tmpfile := filepath.Join(dir, "x.s")
if err := os.WriteFile(tmpfile, []byte("TEXT ·stub(SB),$0-0\nNOP\n"), 0644); err != nil {
t.Fatal(err)
}
cmd := testenv.Command(t, testenv.GoToolPath(t), "tool", "asm", "-o", filepath.Join(dir, "x.o"), tmpfile)
cmd.Env = append(os.Environ(), "GOARCH=riscv64", "GOOS=linux")
if out, err := cmd.CombinedOutput(); err != nil {
t.Errorf("%v\n%s", err, out)
}
}
func TestImmediateSplitting(t *testing.T) {
dir := t.TempDir()
tmpfile := filepath.Join(dir, "x.s")
asm := `
TEXT _stub(SB),$0-0
LB 4096(X5), X6
LH 4096(X5), X6
LW 4096(X5), X6
LD 4096(X5), X6
LBU 4096(X5), X6
LHU 4096(X5), X6
LWU 4096(X5), X6
SB X6, 4096(X5)
SH X6, 4096(X5)
SW X6, 4096(X5)
SD X6, 4096(X5)
FLW 4096(X5), F6
FLD 4096(X5), F6
FSW F6, 4096(X5)
FSD F6, 4096(X5)
MOVB 4096(X5), X6
MOVH 4096(X5), X6
MOVW 4096(X5), X6
MOV 4096(X5), X6
MOVBU 4096(X5), X6
MOVHU 4096(X5), X6
MOVWU 4096(X5), X6
MOVB X6, 4096(X5)
MOVH X6, 4096(X5)
MOVW X6, 4096(X5)
MOV X6, 4096(X5)
MOVF 4096(X5), F6
MOVD 4096(X5), F6
MOVF F6, 4096(X5)
MOVD F6, 4096(X5)
`
if err := os.WriteFile(tmpfile, []byte(asm), 0644); err != nil {
t.Fatal(err)
}
cmd := testenv.Command(t, testenv.GoToolPath(t), "tool", "asm", "-o", filepath.Join(dir, "x.o"), tmpfile)
cmd.Env = append(os.Environ(), "GOARCH=riscv64", "GOOS=linux")
if out, err := cmd.CombinedOutput(); err != nil {
t.Errorf("%v\n%s", err, out)
}
}
func TestBranch(t *testing.T) {
if runtime.GOARCH != "riscv64" {
t.Skip("Requires riscv64 to run")
}
testenv.MustHaveGoBuild(t)
cmd := testenv.Command(t, testenv.GoToolPath(t), "test")
cmd.Dir = "testdata/testbranch"
if out, err := testenv.CleanCmdEnv(cmd).CombinedOutput(); err != nil {
t.Errorf("Branch test failed: %v\n%s", err, out)
}
}
func TestMinMax(t *testing.T) {
if runtime.GOARCH != "riscv64" {
t.Skip("Requires riscv64 to run")
}
testenv.MustHaveGoBuild(t)
cmd := testenv.Command(t, testenv.GoToolPath(t), "test")
cmd.Dir = "testdata/testminmax"
if out, err := testenv.CleanCmdEnv(cmd).CombinedOutput(); err != nil {
t.Errorf("Min max test failed: %v\n%s", err, out)
}
}
func TestPCAlign(t *testing.T) {
dir := t.TempDir()
tmpfile := filepath.Join(dir, "x.s")
asm := `
TEXT _stub(SB),$0-0
FENCE
PCALIGN $8
FENCE
RET
`
if err := os.WriteFile(tmpfile, []byte(asm), 0644); err != nil {
t.Fatal(err)
}
cmd := exec.Command(testenv.GoToolPath(t), "tool", "asm", "-o", filepath.Join(dir, "x.o"), "-S", tmpfile)
cmd.Env = append(os.Environ(), "GOARCH=riscv64", "GOOS=linux")
out, err := cmd.CombinedOutput()
if err != nil {
t.Errorf("Failed to assemble: %v\n%s", err, out)
}
// The expected instruction sequence after alignment:
// FENCE
// NOP
// FENCE
// RET (CJALR or JALR)
want := regexp.MustCompile("0x0000 0f 00 f0 0f 13 00 00 00 0f 00 f0 0f (82 80|67 80 00 00) ")
if !want.Match(out) {
t.Errorf("PCALIGN test failed - got %s\nwant %s", out, want)
}
}