mmcloughlin · mmcloughlin · Oct 28, 2021 · Oct 28, 2021 · Oct 28, 2021 · Oct 28, 2021
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -15,7 +15,7 @@ jobs:
   test:
     strategy:
       matrix:
-        go-version: [1.15.x, 1.16.x]
+        go-version: [1.16.x, 1.17.x]
         platform: [ubuntu-latest]
     runs-on: ${{ matrix.platform }}
     steps:
@@ -59,7 +59,7 @@ jobs:
   lint:
     strategy:
       matrix:
-        go-version: [1.16.x]
+        go-version: [1.17.x]
         platform: [ubuntu-latest]
     runs-on: ${{ matrix.platform }}
     steps:

diff --git a/README.md b/README.md
@@ -36,6 +36,7 @@ $ go get -u github.com/mmcloughlin/avo
 
 [embedmd]:# (examples/add/asm.go)
 ```go
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/attr/make_textflag.go b/attr/make_textflag.go
@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/buildtags/syntax.go b/buildtags/syntax.go
@@ -0,0 +1,40 @@
+package buildtags
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"go/format"
+	"strings"
+)
+
+func PlusBuildSyntaxSupported() bool { return plusbuild }
+
+func GoBuildSyntaxSupported() bool { return gobuild }
+
+func Format(t ConstraintsConvertable) (string, error) {
+	// Print build tags to minimal Go source that can be passed to go/format.
+	src := t.ToConstraints().GoString() + "\npackage stub"
+
+	// Format them.
+	formatted, err := format.Source([]byte(src))
+	if err != nil {
+		return "", fmt.Errorf("format build constraints: %w", err)
+	}
+
+	// Extract the comment lines.
+	buf := bytes.NewReader(formatted)
+	scanner := bufio.NewScanner(buf)
+	output := ""
+	for scanner.Scan() {
+		line := scanner.Text()
+		if strings.HasPrefix(line, "//") {
+			output += line + "\n"
+		}
+	}
+	if err := scanner.Err(); err != nil {
+		return "", fmt.Errorf("parse formatted build constraints: %w", err)
+	}
+
+	return output, nil
+}
diff --git a/buildtags/syntax_go116.go b/buildtags/syntax_go116.go
@@ -0,0 +1,9 @@
+//go:build !go1.17
+// +build !go1.17
+
+package buildtags
+
+const (
+	plusbuild = true
+	gobuild   = false
+)
diff --git a/buildtags/syntax_go117.go b/buildtags/syntax_go117.go
@@ -0,0 +1,9 @@
+//go:build go1.17 && !go1.18
+// +build go1.17,!go1.18
+
+package buildtags
+
+const (
+	plusbuild = true
+	gobuild   = true
+)
diff --git a/buildtags/syntax_go118.go b/buildtags/syntax_go118.go
@@ -0,0 +1,9 @@
+//go:build go1.18
+// +build go1.18
+
+package buildtags
+
+const (
+	plusbuild = false
+	gobuild   = true
+)
diff --git a/examples/add/README.md b/examples/add/README.md
@@ -6,6 +6,7 @@ The [code generator](asm.go) is as follows:
 
 [embedmd]:# (asm.go)
 ```go
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/examples/add/asm.go b/examples/add/asm.go
@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/examples/args/asm.go b/examples/args/asm.go
@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/examples/complex/asm.go b/examples/complex/asm.go
@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/examples/data/asm.go b/examples/data/asm.go
@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/examples/dot/asm.go b/examples/dot/asm.go
@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/examples/ext/asm.go b/examples/ext/asm.go
@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/examples/fnv1a/asm.go b/examples/fnv1a/asm.go
@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/examples/geohash/asm.go b/examples/geohash/asm.go
@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/examples/pragma/asm.go b/examples/pragma/asm.go
@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/examples/returns/asm.go b/examples/returns/asm.go
@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/examples/sha1/asm.go b/examples/sha1/asm.go
@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/examples/sum/asm.go b/examples/sum/asm.go
@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/operand/make_const.go b/operand/make_const.go
@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/printer/goasm.go b/printer/goasm.go
@@ -4,6 +4,7 @@ import (
 	"strconv"
 	"strings"
 
+	"github.com/mmcloughlin/avo/buildtags"
 	"github.com/mmcloughlin/avo/internal/prnt"
 	"github.com/mmcloughlin/avo/ir"
 	"github.com/mmcloughlin/avo/operand"
@@ -44,8 +45,12 @@ func (p *goasm) header(f *ir.File) {
 	p.Comment(p.cfg.GeneratedWarning())
 
 	if len(f.Constraints) > 0 {
+		src, err := buildtags.Format(f.Constraints)
+		if err != nil {
+			p.AddError(err)
+		}
 		p.NL()
-		p.Printf(f.Constraints.GoString())
+		p.Printf(src)
 	}
 
 	if len(f.Includes) > 0 {

diff --git a/printer/goasm_test.go b/printer/goasm_test.go
@@ -5,6 +5,7 @@ import (
 
 	"github.com/mmcloughlin/avo/attr"
 	"github.com/mmcloughlin/avo/build"
+	"github.com/mmcloughlin/avo/buildtags"
 	"github.com/mmcloughlin/avo/printer"
 	"github.com/mmcloughlin/avo/reg"
 )
@@ -73,13 +74,24 @@ func TestConstraints(t *testing.T) {
 	ctx.ConstraintExpr("linux,386 darwin,!cgo")
 	ctx.ConstraintExpr("!noasm")
 
-	AssertPrintsLines(t, ctx, printer.NewGoAsm, []string{
+	expect := []string{
 		"// Code generated by avo. DO NOT EDIT.",
 		"",
-		"// +build linux,386 darwin,!cgo",
-		"// +build !noasm",
-		"",
-	})
+	}
+	if buildtags.GoBuildSyntaxSupported() {
+		expect = append(expect,
+			"//go:build ((linux && 386) || (darwin && !cgo)) && !noasm",
+		)
+	}
+	if buildtags.PlusBuildSyntaxSupported() {
+		expect = append(expect,
+			"// +build linux,386 darwin,!cgo",
+			"// +build !noasm",
+		)
+	}
+	expect = append(expect, "")
+
+	AssertPrintsLines(t, ctx, printer.NewGoAsm, expect)
 }
 
 func TestAlignmentNoOperands(t *testing.T) {

diff --git a/printer/stubs.go b/printer/stubs.go
@@ -1,6 +1,7 @@
 package printer
 
 import (
+	"github.com/mmcloughlin/avo/buildtags"
 	"github.com/mmcloughlin/avo/internal/prnt"
 	"github.com/mmcloughlin/avo/ir"
 )
@@ -19,8 +20,12 @@ func (s *stubs) Print(f *ir.File) ([]byte, error) {
 	s.Comment(s.cfg.GeneratedWarning())
 
 	if len(f.Constraints) > 0 {
+		src, err := buildtags.Format(f.Constraints)
+		if err != nil {
+			s.AddError(err)
+		}
 		s.NL()
-		s.Printf(f.Constraints.GoString())
+		s.Printf(src)
 	}
 
 	s.NL()

diff --git a/script/tools.mod b/script/tools.mod
@@ -5,7 +5,7 @@ go 1.14
 require (
 	github.com/campoy/embedmd v1.0.0 // indirect
 	github.com/dlespiau/covertool v0.0.0-20180314162135-b0c4c6d0583a // indirect
-	github.com/klauspost/asmfmt v1.2.1 // indirect
+	github.com/klauspost/asmfmt v1.3.1 // indirect
 	github.com/urfave/cli v1.22.5 // indirect
 	mvdan.cc/gofumpt v0.0.0-20200412215918-a91da47f375c // indirect
 )
diff --git a/script/tools.sum b/script/tools.sum
@@ -7,6 +7,8 @@ github.com/dlespiau/covertool v0.0.0-20180314162135-b0c4c6d0583a h1:+cYgqwB++gEE
 github.com/dlespiau/covertool v0.0.0-20180314162135-b0c4c6d0583a/go.mod h1:/eQMcW3eA1bzKx23ZYI2H3tXPdJB5JWYTHzoUPBvQY4=
 github.com/klauspost/asmfmt v1.2.1 h1:LgH5hc6QnY2sDT2K+ilscIzcZpfQ1xlayuTyLxo4pOA=
 github.com/klauspost/asmfmt v1.2.1/go.mod h1:RAoUvqkWr2rUa2I19qKMEVZQe4BVtcHGTMCUOcCU2Lg=
+github.com/klauspost/asmfmt v1.3.1 h1:7xZi1N7s9gTLbqiM8KUv8TLyysavbTRGBT5/ly0bRtw=
+github.com/klauspost/asmfmt v1.3.1/go.mod h1:AG8TuvYojzulgDAMCnYn50l/5QV3Bs/tp6j0HLHbNSE=
 github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=

diff --git a/tests/alloc/gp8/asm.go b/tests/alloc/gp8/asm.go
@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/tests/alloc/masks/asm.go b/tests/alloc/masks/asm.go
@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/tests/alloc/upper32/asm.go b/tests/alloc/upper32/asm.go
@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/tests/cast/asm.go b/tests/cast/asm.go
@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/tests/fixedbugs/issue100/allocfail/allocfail.s b/tests/fixedbugs/issue100/allocfail/allocfail.s
@@ -1,8 +1,7 @@
 // Code generated by command: go run asm.go -out allocfail.s -stubs stubs.go. DO NOT EDIT.
 
-// +build !appengine
-// +build !noasm
-// +build gc
+//go:build !appengine && !noasm && gc
+// +build !appengine,!noasm,gc
 
 #include "textflag.h"
 

diff --git a/tests/fixedbugs/issue100/allocfail/asm.go b/tests/fixedbugs/issue100/allocfail/asm.go
@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/tests/fixedbugs/issue100/allocfail/stubs.go b/tests/fixedbugs/issue100/allocfail/stubs.go
diff --git a/tests/fixedbugs/issue100/minrepro/asm.go b/tests/fixedbugs/issue100/minrepro/asm.go
@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/tests/fixedbugs/issue122/asm.go b/tests/fixedbugs/issue122/asm.go
@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/tests/fixedbugs/issue50/asm.go b/tests/fixedbugs/issue50/asm.go
@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/tests/fixedbugs/issue62/asm.go b/tests/fixedbugs/issue62/asm.go
@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/tests/fixedbugs/issue65/asm.go b/tests/fixedbugs/issue65/asm.go
@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/tests/fixedbugs/issue68/asm.go b/tests/fixedbugs/issue68/asm.go
@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/tests/fixedbugs/issue76/asm.go b/tests/fixedbugs/issue76/asm.go
@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/tests/fixedbugs/issue89/asm.go b/tests/fixedbugs/issue89/asm.go
@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/tests/fmt/asm.go b/tests/fmt/asm.go
@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/tests/labels/asm.go b/tests/labels/asm.go
@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main

diff --git a/tests/textflag/make_attrtest.go b/tests/textflag/make_attrtest.go
@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main