mirror of https://github.com/golang/go.git
cmd/compile: set lexer nlsemi state directly
The old code used an extra function call and switch to inspect the current token and determine the new state of curio.nlsemi. However, the lexer knows the token w/o the need of an extra test and thus can set curio.nlsemi directly: - removed need for extra function call in next - renamed _yylex to next - set nlsemi at the point a token is identified - moved nlsemi from curio to lexer - it's really part of the lexer state This change makes the lexer call sequence less convoluted and should also speed up the lexing a bit. Change-Id: Iaf2683081f04231cb62c94e1400d455f98f6f82a Reviewed-on: https://go-review.googlesource.com/19765 Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This commit is contained in:
Robert Griesemer
parent
20ee67acc9
commit
aa5b44aeab
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@ -389,7 +389,6 @@ type Io struct {
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last int
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peekc int
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peekc1 int // second peekc for ...
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nlsemi bool
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eofnl bool
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}
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@ -869,6 +869,7 @@ func isfrog(c int) bool {
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type lexer struct {
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// TODO(gri) move other lexer state here and out of global variables
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// (source, current line number, etc.)
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nlsemi bool // if set, '\n' and EOF translate to ';'
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// current token
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tok int32
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@ -925,7 +926,7 @@ const (
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LRSH
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)
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func (yylval *lexer) _yylex() int32 {
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func (l *lexer) next() {
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var c1 int
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var op Op
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var escflag int
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@ -936,27 +937,31 @@ func (yylval *lexer) _yylex() int32 {
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prevlineno = lineno
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nlsemi := l.nlsemi
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l.nlsemi = false
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l0:
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// skip white space
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c := getc()
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if isSpace(c) {
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if c == '\n' && curio.nlsemi {
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for isSpace(c) {
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if c == '\n' && nlsemi {
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ungetc(c)
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if Debug['x'] != 0 {
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fmt.Printf("lex: implicit semi\n")
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}
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return ';'
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l.tok = ';'
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return
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}
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goto l0
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c = getc()
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}
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lineno = lexlineno // start of token
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// start of token
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lineno = lexlineno
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if c >= utf8.RuneSelf {
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// all multibyte runes are alpha
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cp = &lexbuf
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cp.Reset()
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goto talph
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}
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@ -1049,7 +1054,17 @@ l0:
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case EOF:
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lineno = prevlineno
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ungetc(EOF)
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return -1
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// Treat EOF as "end of line" for the purposes
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// of inserting a semicolon.
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if nlsemi {
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if Debug['x'] != 0 {
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fmt.Printf("lex: implicit semi\n")
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}
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l.tok = ';'
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return
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}
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l.tok = -1
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return
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case '_':
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cp = &lexbuf
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@ -1137,14 +1152,16 @@ l0:
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}
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x := new(Mpint)
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yylval.val.U = x
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l.val.U = x
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Mpmovecfix(x, v)
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x.Rune = true
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if Debug['x'] != 0 {
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fmt.Printf("lex: codepoint literal\n")
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}
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litbuf = "string literal"
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return LLITERAL
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l.nlsemi = true
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l.tok = LLITERAL
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return
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case '/':
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c1 = getc()
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@ -1217,6 +1234,7 @@ l0:
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case '+':
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c1 = getc()
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if c1 == '+' {
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l.nlsemi = true
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c = int(LINC)
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goto lx
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}
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@ -1229,6 +1247,7 @@ l0:
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case '-':
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c1 = getc()
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if c1 == '-' {
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l.nlsemi = true
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c = int(LDEC)
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goto lx
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}
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@ -1339,6 +1358,10 @@ l0:
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goto asop
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}
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case ')', ']', '}':
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l.nlsemi = true
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goto lx
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default:
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goto lx
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}
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@ -1363,14 +1386,16 @@ lx:
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goto l0
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}
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return int32(c)
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l.tok = int32(c)
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return
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asop:
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yylval.op = op
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l.op = op
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if Debug['x'] != 0 {
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fmt.Printf("lex: TOKEN ASOP %s=\n", goopnames[op])
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}
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return LASOP
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l.tok = LASOP
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return
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// cp is set to lexbuf and some
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// prefix has been stored
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@ -1407,26 +1432,33 @@ talph:
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if Debug['x'] != 0 {
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fmt.Printf("lex: %s %s\n", s, lexname(int(s.Lexical)))
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}
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yylval.sym_ = s
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return int32(s.Lexical)
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l.sym_ = s
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switch s.Lexical {
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case LNAME, LRETURN, LBREAK, LCONTINUE, LFALL:
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l.nlsemi = true
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}
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l.tok = int32(s.Lexical)
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return
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ncu:
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cp = nil
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ungetc(c)
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str = lexbuf.String()
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yylval.val.U = new(Mpint)
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mpatofix(yylval.val.U.(*Mpint), str)
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if yylval.val.U.(*Mpint).Ovf {
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l.val.U = new(Mpint)
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mpatofix(l.val.U.(*Mpint), str)
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if l.val.U.(*Mpint).Ovf {
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Yyerror("overflow in constant")
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Mpmovecfix(yylval.val.U.(*Mpint), 0)
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Mpmovecfix(l.val.U.(*Mpint), 0)
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}
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if Debug['x'] != 0 {
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fmt.Printf("lex: integer literal\n")
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}
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litbuf = "literal " + str
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return LLITERAL
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l.nlsemi = true
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l.tok = LLITERAL
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return
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casedot:
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for {
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@ -1475,45 +1507,50 @@ casei:
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cp = nil
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str = lexbuf.String()
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yylval.val.U = new(Mpcplx)
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Mpmovecflt(&yylval.val.U.(*Mpcplx).Real, 0.0)
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mpatoflt(&yylval.val.U.(*Mpcplx).Imag, str)
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if yylval.val.U.(*Mpcplx).Imag.Val.IsInf() {
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l.val.U = new(Mpcplx)
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Mpmovecflt(&l.val.U.(*Mpcplx).Real, 0.0)
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mpatoflt(&l.val.U.(*Mpcplx).Imag, str)
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if l.val.U.(*Mpcplx).Imag.Val.IsInf() {
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Yyerror("overflow in imaginary constant")
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Mpmovecflt(&yylval.val.U.(*Mpcplx).Imag, 0.0)
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Mpmovecflt(&l.val.U.(*Mpcplx).Imag, 0.0)
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}
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if Debug['x'] != 0 {
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fmt.Printf("lex: imaginary literal\n")
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}
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litbuf = "literal " + str
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return LLITERAL
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l.nlsemi = true
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l.tok = LLITERAL
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return
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caseout:
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cp = nil
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ungetc(c)
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str = lexbuf.String()
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yylval.val.U = newMpflt()
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mpatoflt(yylval.val.U.(*Mpflt), str)
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if yylval.val.U.(*Mpflt).Val.IsInf() {
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l.val.U = newMpflt()
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mpatoflt(l.val.U.(*Mpflt), str)
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if l.val.U.(*Mpflt).Val.IsInf() {
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Yyerror("overflow in float constant")
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Mpmovecflt(yylval.val.U.(*Mpflt), 0.0)
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Mpmovecflt(l.val.U.(*Mpflt), 0.0)
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}
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if Debug['x'] != 0 {
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fmt.Printf("lex: floating literal\n")
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}
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litbuf = "literal " + str
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return LLITERAL
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l.nlsemi = true
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l.tok = LLITERAL
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return
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strlit:
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yylval.val.U = internString(cp.Bytes())
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l.val.U = internString(cp.Bytes())
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if Debug['x'] != 0 {
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fmt.Printf("lex: string literal\n")
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}
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litbuf = "string literal"
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return LLITERAL
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l.nlsemi = true
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l.tok = LLITERAL
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}
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var internedStrings = map[string]string{}
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@ -1833,36 +1870,6 @@ func pragcgo(text string) {
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}
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}
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func (l *lexer) next() {
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tok := l._yylex()
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if curio.nlsemi && tok == EOF {
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// Treat EOF as "end of line" for the purposes
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// of inserting a semicolon.
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tok = ';'
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}
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switch tok {
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case LNAME,
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LLITERAL,
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LBREAK,
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LCONTINUE,
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LFALL,
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LRETURN,
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LINC,
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LDEC,
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')',
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'}',
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']':
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curio.nlsemi = true
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default:
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curio.nlsemi = false
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}
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l.tok = tok
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}
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func getc() int {
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c := curio.peekc
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if c != 0 {
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