all: remove +build tags (#377)

Commit 759be3dad9 bumped our Go
requirement to 1.18 which allows us to drop support for old-style
`+build` tags. This change runs `go fix ./...` to remove them, and
updates some remaining code generators that produced `+build` lines.

README.md

@@ -37,7 +37,6 @@ $ go get -u github.com/mmcloughlin/avo
 
 ```go
 //go:build ignore
-// +build ignore
 
 package main
 

attr/make_textflag.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

build/zinstructions_test.go

@@ -1,7 +1,6 @@
 // Code generated by command: avogen -output zinstructions_test.go buildtest. DO NOT EDIT.
 
 //go:build !integration
-// +build !integration
 
 package build
 

buildtags/syntax_go116.go

@@ -1,5 +1,4 @@
 //go:build !go1.17
-// +build !go1.17
 
 package buildtags
 

buildtags/syntax_go117.go

@@ -1,5 +1,4 @@
 //go:build go1.17 && !go1.18
-// +build go1.17,!go1.18
 
 package buildtags
 

buildtags/syntax_go118.go

@@ -1,5 +1,4 @@
 //go:build go1.18
-// +build go1.18
 
 package buildtags
 

examples/add/README.md

@@ -7,7 +7,6 @@ The [code generator](asm.go) is as follows:
 [embedmd]:# (asm.go)
 ```go
 //go:build ignore
-// +build ignore
 
 package main
 

examples/add/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

examples/args/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

examples/complex/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

examples/data/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

examples/dot/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

examples/ext/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

examples/fnv1a/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

examples/geohash/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

examples/md5x16/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

examples/pragma/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

examples/returns/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

examples/sha1/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

examples/stadtx/asm.go

@@ -1,4 +1,4 @@
-// +build ignore
+//go:build ignore
 
 package main
 

examples/sum/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

internal/gen/buildtest.go

@@ -20,7 +20,7 @@ func NewBuildTest(cfg printer.Config) Interface {
 
 func (b *buildtest) Generate(is []inst.Instruction) ([]byte, error) {
 	b.Printf("// %s\n\n", b.cfg.GeneratedWarning())
-	b.BuildTag("!integration")
+	b.BuildConstraint("!integration")
 	b.NL()
 	b.Printf("package build\n\n")
 	b.Printf("import (\n")

internal/gen/ctorstest.go

@@ -23,7 +23,7 @@ func NewCtorsTest(cfg printer.Config) Interface {
 
 func (c *ctorstest) Generate(is []inst.Instruction) ([]byte, error) {
 	c.Printf("// %s\n\n", c.cfg.GeneratedWarning())
-	c.BuildTag("!integration")
+	c.BuildConstraint("!integration")
 	c.NL()
 	c.Printf("package x86\n\n")
 	c.Printf("import (\n")
@@ -65,7 +65,7 @@ func NewCtorsStress(cfg printer.Config) Interface {
 
 func (c *ctorsstress) Generate(is []inst.Instruction) ([]byte, error) {
 	c.Printf("// %s\n\n", c.cfg.GeneratedWarning())
-	c.BuildTag("stress")
+	c.BuildConstraint("stress")
 	c.NL()
 	c.Printf("package x86\n\n")
 	c.Printf("import (\n")
@@ -112,7 +112,7 @@ func NewCtorsBench(cfg printer.Config) Interface {
 
 func (c *ctorsbench) Generate(is []inst.Instruction) ([]byte, error) {
 	c.Printf("// %s\n\n", c.cfg.GeneratedWarning())
-	c.BuildTag("stress")
+	c.BuildConstraint("stress")
 	c.NL()
 	c.Printf("package x86\n\n")
 	c.Printf("import (\n")

internal/inst/stress_test.go

@@ -2,7 +2,6 @@
 // stress-test only build.
 
 //go:build stress
-// +build stress
 
 package inst
 

internal/prnt/printer.go

@@ -4,6 +4,7 @@ package prnt
 import (
 	"bytes"
 	"fmt"
+	"go/build/constraint"
 	"io"
 	"strings"
 )
@@ -75,9 +76,13 @@ func (g *Generator) Comment(lines ...string) {
 	}
 }
 
-// BuildTag outputs a build tag.
-func (g *Generator) BuildTag(tag string) {
-	g.Comment("+build " + tag)
+// BuildConstraint outputs a build constraint.
+func (g *Generator) BuildConstraint(expr string) {
+	line := fmt.Sprintf("//go:build %s", expr)
+	if _, err := constraint.Parse(line); err != nil {
+		g.AddError(err)
+	}
+	g.Linef(line)
 }
 
 // AddError records an error in code generation. The first non-nil error will

operand/make_const.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

tests/alloc/gp8/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

tests/alloc/masks/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

tests/alloc/upper32/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

tests/alloc/zeroing/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

tests/cast/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

tests/fixedbugs/issue100/allocfail/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

tests/fixedbugs/issue100/minrepro/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

tests/fixedbugs/issue122/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

tests/fixedbugs/issue191/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

tests/fixedbugs/issue195/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

tests/fixedbugs/issue336/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

tests/fixedbugs/issue50/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

tests/fixedbugs/issue62/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

tests/fixedbugs/issue65/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

tests/fixedbugs/issue68/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

tests/fixedbugs/issue76/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

tests/fixedbugs/issue89/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

tests/fmt/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

tests/labels/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

tests/signature/asm.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

tests/textflag/make_attrtest.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

tests/thirdparty/make_workflow.go

@@ -1,5 +1,4 @@
 //go:build ignore
-// +build ignore
 
 package main
 

x86/stress_test.go

@@ -2,7 +2,6 @@
 // are limited to stress-test mode.
 
 //go:build stress
-// +build stress
 
 package x86
 

x86/zctors_test.go

@@ -1,7 +1,6 @@
 // Code generated by command: avogen -output zctors_test.go ctorstest. DO NOT EDIT.
 
 //go:build !integration
-// +build !integration
 
 package x86