From 2c6df2e35dd95621d025306a49b863efd77ebf3a Mon Sep 17 00:00:00 2001 From: Russ Cox Date: Fri, 22 May 2020 15:22:52 -0400 Subject: [PATCH] cmd/compile: reject misplaced go:build comments We are converting from using error-prone ad-hoc syntax // +build lines to less error-prone, standard boolean syntax //go:build lines. The timeline is: Go 1.16: prepare for transition - Builds still use // +build for file selection. - Source files may not contain //go:build without // +build. - Builds fail when a source file contains //go:build lines without // +build lines. <<< Go 1.17: start transition - Builds prefer //go:build for file selection, falling back to // +build for files containing only // +build. - Source files may contain //go:build without // +build (but they won't build with Go 1.16). - Gofmt moves //go:build and // +build lines to proper file locations. - Gofmt introduces //go:build lines into files with only // +build lines. - Go vet rejects files with mismatched //go:build and // +build lines. Go 1.18: complete transition - Go fix removes // +build lines, leaving behind equivalent // +build lines. This CL provides part of the <<< marked line above in the Go 1.16 step: rejecting files containing //go:build but not // +build. The standard go command checks only consider the top of the file. This compiler check, along with a separate go vet check for ignored files, handles the remainder of the file. For #41184. Change-Id: I014006eebfc84ab5943de18bc90449e534f150a2 Reviewed-on: https://go-review.googlesource.com/c/go/+/240601 Trust: Russ Cox Run-TryBot: Russ Cox TryBot-Result: Go Bot Reviewed-by: Ian Lance Taylor --- src/cmd/compile/internal/gc/lex.go | 5 +++++ src/cmd/compile/internal/gc/noder.go | 1 + test/directive.go | 7 +++++++ 3 files changed, 13 insertions(+) diff --git a/src/cmd/compile/internal/gc/lex.go b/src/cmd/compile/internal/gc/lex.go index 25bc0399ce..7cce371408 100644 --- a/src/cmd/compile/internal/gc/lex.go +++ b/src/cmd/compile/internal/gc/lex.go @@ -50,6 +50,9 @@ const ( // Runtime and cgo type pragmas NotInHeap // values of this type must not be heap allocated + + // Go command pragmas + GoBuildPragma ) const ( @@ -71,6 +74,8 @@ const ( func pragmaFlag(verb string) PragmaFlag { switch verb { + case "go:build": + return GoBuildPragma case "go:nointerface": if objabi.Fieldtrack_enabled != 0 { return Nointerface diff --git a/src/cmd/compile/internal/gc/noder.go b/src/cmd/compile/internal/gc/noder.go index 5dce533e4b..c63c80dd36 100644 --- a/src/cmd/compile/internal/gc/noder.go +++ b/src/cmd/compile/internal/gc/noder.go @@ -242,6 +242,7 @@ func (p *noder) node() { mkpackage(p.file.PkgName.Value) if pragma, ok := p.file.Pragma.(*Pragma); ok { + pragma.Flag &^= GoBuildPragma p.checkUnused(pragma) } diff --git a/test/directive.go b/test/directive.go index 6167cd6279..37781c30d5 100644 --- a/test/directive.go +++ b/test/directive.go @@ -6,11 +6,16 @@ // Verify that misplaced directives are diagnosed. +// ok +//go:build !ignore + //go:noinline // ERROR "misplaced compiler directive" //go:noinline // ERROR "misplaced compiler directive" package main +//go:build bad // ERROR "misplaced compiler directive" + //go:nosplit func f1() {} @@ -93,3 +98,5 @@ type T6 = int // EOF //go:noinline // ERROR "misplaced compiler directive" + +//go:build bad // ERROR "misplaced compiler directive"