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>
diff --git a/src/cmd/compile/internal/gc/go.go b/src/cmd/compile/internal/gc/go.go
index 9b55eb8..d21b2fb 100644
--- a/src/cmd/compile/internal/gc/go.go
+++ b/src/cmd/compile/internal/gc/go.go
@@ -389,7 +389,6 @@
last int
peekc int
peekc1 int // second peekc for ...
- nlsemi bool
eofnl bool
}
diff --git a/src/cmd/compile/internal/gc/lex.go b/src/cmd/compile/internal/gc/lex.go
index 55d988b..54c69c5 100644
--- a/src/cmd/compile/internal/gc/lex.go
+++ b/src/cmd/compile/internal/gc/lex.go
@@ -869,6 +869,7 @@
type lexer struct {
// TODO(gri) move other lexer state here and out of global variables
// (source, current line number, etc.)
+ nlsemi bool // if set, '\n' and EOF translate to ';'
// current token
tok int32
@@ -925,7 +926,7 @@
LRSH
)
-func (yylval *lexer) _yylex() int32 {
+func (l *lexer) next() {
var c1 int
var op Op
var escflag int
@@ -936,27 +937,31 @@
prevlineno = lineno
+ nlsemi := l.nlsemi
+ l.nlsemi = false
+
l0:
+ // skip white space
c := getc()
- if isSpace(c) {
- if c == '\n' && curio.nlsemi {
+ for isSpace(c) {
+ if c == '\n' && nlsemi {
ungetc(c)
if Debug['x'] != 0 {
fmt.Printf("lex: implicit semi\n")
}
- return ';'
+ l.tok = ';'
+ return
}
-
- goto l0
+ c = getc()
}
- lineno = lexlineno // start of token
+ // start of token
+ lineno = lexlineno
if c >= utf8.RuneSelf {
// all multibyte runes are alpha
cp = &lexbuf
cp.Reset()
-
goto talph
}
@@ -1049,7 +1054,17 @@
case EOF:
lineno = prevlineno
ungetc(EOF)
- return -1
+ // Treat EOF as "end of line" for the purposes
+ // of inserting a semicolon.
+ if nlsemi {
+ if Debug['x'] != 0 {
+ fmt.Printf("lex: implicit semi\n")
+ }
+ l.tok = ';'
+ return
+ }
+ l.tok = -1
+ return
case '_':
cp = &lexbuf
@@ -1137,14 +1152,16 @@
}
x := new(Mpint)
- yylval.val.U = x
+ l.val.U = x
Mpmovecfix(x, v)
x.Rune = true
if Debug['x'] != 0 {
fmt.Printf("lex: codepoint literal\n")
}
litbuf = "string literal"
- return LLITERAL
+ l.nlsemi = true
+ l.tok = LLITERAL
+ return
case '/':
c1 = getc()
@@ -1217,6 +1234,7 @@
case '+':
c1 = getc()
if c1 == '+' {
+ l.nlsemi = true
c = int(LINC)
goto lx
}
@@ -1229,6 +1247,7 @@
case '-':
c1 = getc()
if c1 == '-' {
+ l.nlsemi = true
c = int(LDEC)
goto lx
}
@@ -1339,6 +1358,10 @@
goto asop
}
+ case ')', ']', '}':
+ l.nlsemi = true
+ goto lx
+
default:
goto lx
}
@@ -1363,14 +1386,16 @@
goto l0
}
- return int32(c)
+ l.tok = int32(c)
+ return
asop:
- yylval.op = op
+ l.op = op
if Debug['x'] != 0 {
fmt.Printf("lex: TOKEN ASOP %s=\n", goopnames[op])
}
- return LASOP
+ l.tok = LASOP
+ return
// cp is set to lexbuf and some
// prefix has been stored
@@ -1407,26 +1432,33 @@
if Debug['x'] != 0 {
fmt.Printf("lex: %s %s\n", s, lexname(int(s.Lexical)))
}
- yylval.sym_ = s
- return int32(s.Lexical)
+ l.sym_ = s
+ switch s.Lexical {
+ case LNAME, LRETURN, LBREAK, LCONTINUE, LFALL:
+ l.nlsemi = true
+ }
+ l.tok = int32(s.Lexical)
+ return
ncu:
cp = nil
ungetc(c)
str = lexbuf.String()
- yylval.val.U = new(Mpint)
- mpatofix(yylval.val.U.(*Mpint), str)
- if yylval.val.U.(*Mpint).Ovf {
+ l.val.U = new(Mpint)
+ mpatofix(l.val.U.(*Mpint), str)
+ if l.val.U.(*Mpint).Ovf {
Yyerror("overflow in constant")
- Mpmovecfix(yylval.val.U.(*Mpint), 0)
+ Mpmovecfix(l.val.U.(*Mpint), 0)
}
if Debug['x'] != 0 {
fmt.Printf("lex: integer literal\n")
}
litbuf = "literal " + str
- return LLITERAL
+ l.nlsemi = true
+ l.tok = LLITERAL
+ return
casedot:
for {
@@ -1475,45 +1507,50 @@
cp = nil
str = lexbuf.String()
- yylval.val.U = new(Mpcplx)
- Mpmovecflt(&yylval.val.U.(*Mpcplx).Real, 0.0)
- mpatoflt(&yylval.val.U.(*Mpcplx).Imag, str)
- if yylval.val.U.(*Mpcplx).Imag.Val.IsInf() {
+ l.val.U = new(Mpcplx)
+ Mpmovecflt(&l.val.U.(*Mpcplx).Real, 0.0)
+ mpatoflt(&l.val.U.(*Mpcplx).Imag, str)
+ if l.val.U.(*Mpcplx).Imag.Val.IsInf() {
Yyerror("overflow in imaginary constant")
- Mpmovecflt(&yylval.val.U.(*Mpcplx).Imag, 0.0)
+ Mpmovecflt(&l.val.U.(*Mpcplx).Imag, 0.0)
}
if Debug['x'] != 0 {
fmt.Printf("lex: imaginary literal\n")
}
litbuf = "literal " + str
- return LLITERAL
+ l.nlsemi = true
+ l.tok = LLITERAL
+ return
caseout:
cp = nil
ungetc(c)
str = lexbuf.String()
- yylval.val.U = newMpflt()
- mpatoflt(yylval.val.U.(*Mpflt), str)
- if yylval.val.U.(*Mpflt).Val.IsInf() {
+ l.val.U = newMpflt()
+ mpatoflt(l.val.U.(*Mpflt), str)
+ if l.val.U.(*Mpflt).Val.IsInf() {
Yyerror("overflow in float constant")
- Mpmovecflt(yylval.val.U.(*Mpflt), 0.0)
+ Mpmovecflt(l.val.U.(*Mpflt), 0.0)
}
if Debug['x'] != 0 {
fmt.Printf("lex: floating literal\n")
}
litbuf = "literal " + str
- return LLITERAL
+ l.nlsemi = true
+ l.tok = LLITERAL
+ return
strlit:
- yylval.val.U = internString(cp.Bytes())
+ l.val.U = internString(cp.Bytes())
if Debug['x'] != 0 {
fmt.Printf("lex: string literal\n")
}
litbuf = "string literal"
- return LLITERAL
+ l.nlsemi = true
+ l.tok = LLITERAL
}
var internedStrings = map[string]string{}
@@ -1833,36 +1870,6 @@
}
}
-func (l *lexer) next() {
- tok := l._yylex()
-
- if curio.nlsemi && tok == EOF {
- // Treat EOF as "end of line" for the purposes
- // of inserting a semicolon.
- tok = ';'
- }
-
- switch tok {
- case LNAME,
- LLITERAL,
- LBREAK,
- LCONTINUE,
- LFALL,
- LRETURN,
- LINC,
- LDEC,
- ')',
- '}',
- ']':
- curio.nlsemi = true
-
- default:
- curio.nlsemi = false
- }
-
- l.tok = tok
-}
-
func getc() int {
c := curio.peekc
if c != 0 {
