From 85f829deb8adfb7c0d73acabfdb458de969f6763 Mon Sep 17 00:00:00 2001 From: Russ Cox Date: Mon, 29 Jun 2020 17:08:49 -0400 Subject: cmd/asm: 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. Reject any //go:build comments found after actual assembler code (include #include etc directives), because the go command itself doesn't read that far. For #41184. Change-Id: Ib460bfd380cce4239993980dd208afd07deff3f1 Reviewed-on: https://go-review.googlesource.com/c/go/+/240602 Trust: Russ Cox Run-TryBot: Russ Cox TryBot-Result: Go Bot Reviewed-by: Ian Lance Taylor --- src/cmd/asm/internal/lex/input.go | 3 +++ src/cmd/asm/internal/lex/lex.go | 12 +++++++----- src/cmd/asm/internal/lex/lex_test.go | 3 +++ src/cmd/asm/internal/lex/tokenizer.go | 11 +++++++---- 4 files changed, 20 insertions(+), 9 deletions(-) (limited to 'src/cmd/asm/internal/lex') diff --git a/src/cmd/asm/internal/lex/input.go b/src/cmd/asm/internal/lex/input.go index a43953b515..da4ebe6d6e 100644 --- a/src/cmd/asm/internal/lex/input.go +++ b/src/cmd/asm/internal/lex/input.go @@ -109,6 +109,9 @@ func (in *Input) Next() ScanToken { in.Error("'#' must be first item on line") } in.beginningOfLine = in.hash() + in.text = "#" + return '#' + case scanner.Ident: // Is it a macro name? name := in.Stack.Text() diff --git a/src/cmd/asm/internal/lex/lex.go b/src/cmd/asm/internal/lex/lex.go index f1f7da7911..7cd41a55a9 100644 --- a/src/cmd/asm/internal/lex/lex.go +++ b/src/cmd/asm/internal/lex/lex.go @@ -22,11 +22,13 @@ type ScanToken rune const ( // Asm defines some two-character lexemes. We make up // a rune/ScanToken value for them - ugly but simple. - LSH ScanToken = -1000 - iota // << Left shift. - RSH // >> Logical right shift. - ARR // -> Used on ARM for shift type 3, arithmetic right shift. - ROT // @> Used on ARM for shift type 4, rotate right. - macroName // name of macro that should not be expanded + LSH ScanToken = -1000 - iota // << Left shift. + RSH // >> Logical right shift. + ARR // -> Used on ARM for shift type 3, arithmetic right shift. + ROT // @> Used on ARM for shift type 4, rotate right. + Include // included file started here + BuildComment // //go:build or +build comment + macroName // name of macro that should not be expanded ) // IsRegisterShift reports whether the token is one of the ARM register shift operators. diff --git a/src/cmd/asm/internal/lex/lex_test.go b/src/cmd/asm/internal/lex/lex_test.go index f606ffe07b..51679d2fbc 100644 --- a/src/cmd/asm/internal/lex/lex_test.go +++ b/src/cmd/asm/internal/lex/lex_test.go @@ -281,6 +281,9 @@ func drain(input *Input) string { if tok == scanner.EOF { return buf.String() } + if tok == '#' { + continue + } if buf.Len() > 0 { buf.WriteByte('.') } diff --git a/src/cmd/asm/internal/lex/tokenizer.go b/src/cmd/asm/internal/lex/tokenizer.go index aef9ea8636..861a2d421d 100644 --- a/src/cmd/asm/internal/lex/tokenizer.go +++ b/src/cmd/asm/internal/lex/tokenizer.go @@ -107,10 +107,13 @@ func (t *Tokenizer) Next() ScanToken { if t.tok != scanner.Comment { break } - length := strings.Count(s.TokenText(), "\n") - t.line += length - // TODO: If we ever have //go: comments in assembly, will need to keep them here. - // For now, just discard all comments. + text := s.TokenText() + t.line += strings.Count(text, "\n") + // TODO: Use constraint.IsGoBuild once it exists. + if strings.HasPrefix(text, "//go:build") { + t.tok = BuildComment + break + } } switch t.tok { case '\n': -- cgit v1.3