cmd/compile: eliminate iota_

Change-Id: Iad9c1961aedcc754ad2f6010a49f94c5a0a4bfee
Reviewed-on: https://go-review.googlesource.com/32487
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

diff --git a/src/cmd/compile/internal/gc/dcl.go b/src/cmd/compile/internal/gc/dcl.go
index 6cf970dbad6bf07e7f18d7e98c518cffe2463a78..2a678dc2c08d56d6ccebab2101bdd8c2ebbde43b 100644 (file)
--- a/src/cmd/compile/internal/gc/dcl.go
+++ b/src/cmd/compile/internal/gc/dcl.go
@@ -288,7 +288,7 @@ func variter(vl []*Node, t *Node, el []*Node) []*Node {
 
 // declare constants from grammar
 // new_name_list [[type] = expr_list]
-func constiter(vl []*Node, t *Node, cl []*Node) []*Node {
+func constiter(vl []*Node, t *Node, cl []*Node, iotaVal int64) []*Node {
        var lno src.XPos // default is to leave line number alone in listtreecopy
        if len(cl) == 0 {
                if t != nil {
@@ -301,31 +301,29 @@ func constiter(vl []*Node, t *Node, cl []*Node) []*Node {
                lastconst = cl
                lasttype = t
        }
-       clcopy := listtreecopy(cl, lno)
 
        var vv []*Node
-       for _, v := range vl {
-               if len(clcopy) == 0 {
+       for i, v := range vl {
+               if i >= len(cl) {
                        yyerror("missing value in const declaration")
                        break
                }
 
-               c := clcopy[0]
-               clcopy = clcopy[1:]
+               c := treecopy(cl[i], lno)
 
                v.Op = OLITERAL
                declare(v, dclcontext)
 
                v.Name.Param.Ntype = t
                v.Name.Defn = c
+               v.SetIota(iotaVal)
 
                vv = append(vv, nod(ODCLCONST, v, nil))
        }
 
-       if len(clcopy) != 0 {
+       if len(cl) > len(vl) {
                yyerror("extra expression in const declaration")
        }
-       iota_ += 1
        return vv
 }
 
@@ -401,9 +399,7 @@ func oldname(s *Sym) *Node {
                // Maybe a top-level declaration will come along later to
                // define s. resolve will check s.Def again once all input
                // source has been processed.
-               n = newnoname(s)
-               n.SetIota(iota_) // save current iota value in const declarations
-               return n
+               return newnoname(s)
        }
 
        if Curfn != nil && n.Op == ONAME && n.Name.Funcdepth > 0 && n.Name.Funcdepth != funcdepth {

diff --git a/src/cmd/compile/internal/gc/go.go b/src/cmd/compile/internal/gc/go.go
index 07c4d03b8bd71af6fd7bed9db3f44997ac96af44..a460b415d831bca42792540a484c1472e78d5390 100644 (file)
--- a/src/cmd/compile/internal/gc/go.go
+++ b/src/cmd/compile/internal/gc/go.go
@@ -223,8 +223,6 @@ var dclcontext Class // PEXTERN/PAUTO
 
 var statuniqgen int // name generator for static temps
 
-var iota_ int64
-
 var lastconst []*Node
 
 var lasttype *Node

diff --git a/src/cmd/compile/internal/gc/main.go b/src/cmd/compile/internal/gc/main.go
index a9f041c4c37954ab17ced21b868ff86b304d5844..d1dbe45c71acbc3bc8a6a305052848e5f5927ff8 100644 (file)
--- a/src/cmd/compile/internal/gc/main.go
+++ b/src/cmd/compile/internal/gc/main.go
@@ -679,7 +679,6 @@ func findpkg(name string) (file string, ok bool) {
 // but does not make them visible to user code.
 func loadsys() {
        block = 1
-       iota_ = -1000000
 
        importpkg = Runtimepkg
        typecheckok = true

diff --git a/src/cmd/compile/internal/gc/noder.go b/src/cmd/compile/internal/gc/noder.go
index e4378544f0114d5225d9a761185bd9ed6b44bbcd..2de5b18f7c1456601dd053d74c30a98cbc257379 100644 (file)
--- a/src/cmd/compile/internal/gc/noder.go
+++ b/src/cmd/compile/internal/gc/noder.go
@@ -85,7 +85,6 @@ type linkname struct {
 
 func (p *noder) node() {
        block = 1
-       iota_ = -1000000
        imported_unsafe = false
 
        p.lineno(p.file.PkgName)
@@ -134,22 +133,18 @@ func (p *noder) decls(decls []syntax.Decl) (l []*Node) {
                case *syntax.ConstDecl:
                        // Tricky to handle golang.org/issue/15550 correctly.
 
-                       prevIota := iota_
-
                        if decl.Group == nil || decl.Group != lastConstGroup {
                                iotaVal = 0
                                lastConstRHS = nil
                        }
 
-                       iota_ = iotaVal
                        lastconst = lastConstRHS
 
-                       l = append(l, p.constDecl(decl)...)
+                       l = append(l, p.constDecl(decl, iotaVal)...)
 
                        lastConstRHS = lastconst
                        lastconst = nil
 
-                       iota_ = prevIota
                        iotaVal++
 
                        lastConstGroup = decl.Group
@@ -227,7 +222,7 @@ func (p *noder) varDecl(decl *syntax.VarDecl) []*Node {
        return variter(names, typ, exprs)
 }
 
-func (p *noder) constDecl(decl *syntax.ConstDecl) []*Node {
+func (p *noder) constDecl(decl *syntax.ConstDecl, iotaVal int64) []*Node {
        names := p.declNames(decl.NameList)
        typ := p.typeExprOrNil(decl.Type)
 
@@ -236,7 +231,7 @@ func (p *noder) constDecl(decl *syntax.ConstDecl) []*Node {
                exprs = p.exprList(decl.Values)
        }
 
-       return constiter(names, typ, exprs)
+       return constiter(names, typ, exprs, iotaVal)
 }
 
 func (p *noder) typeDecl(decl *syntax.TypeDecl) *Node {

diff --git a/src/cmd/compile/internal/gc/subr.go b/src/cmd/compile/internal/gc/subr.go
index 6a5e1a478e6d4d572b7691d892cba6fd8d7ec5be..c7baea9837759364c322ceaf7fa788b40d7722f5 100644 (file)
--- a/src/cmd/compile/internal/gc/subr.go
+++ b/src/cmd/compile/internal/gc/subr.go
@@ -476,28 +476,13 @@ func treecopy(n *Node, pos src.XPos) *Node {
                }
                return &m
 
-       case ONONAME:
-               if n.Sym == lookup("iota") {
-                       // Not sure yet whether this is the real iota,
-                       // but make a copy of the Node* just in case,
-                       // so that all the copies of this const definition
-                       // don't have the same iota value.
-                       m := *n
-                       if pos.IsKnown() {
-                               m.Pos = pos
-                       }
-                       m.SetIota(iota_)
-                       return &m
-               }
-               return n
-
        case OPACK:
                // OPACK nodes are never valid in const value declarations,
                // but allow them like any other declared symbol to avoid
                // crashing (golang.org/issue/11361).
                fallthrough
 
-       case ONAME, OLITERAL, OTYPE:
+       case ONAME, ONONAME, OLITERAL, OTYPE:
                return n
 
        }

diff --git a/src/cmd/compile/internal/gc/syntax.go b/src/cmd/compile/internal/gc/syntax.go
index 923055c9622d3e131e783a911d988c946152ef3e..b0cf77d47919b9643ec62e031763d52480bd2a49 100644 (file)
--- a/src/cmd/compile/internal/gc/syntax.go
+++ b/src/cmd/compile/internal/gc/syntax.go
@@ -43,7 +43,7 @@ type Node struct {
        // - ODOT, ODOTPTR, and OINDREGSP use it to indicate offset relative to their base address.
        // - OSTRUCTKEY uses it to store the named field's offset.
        // - OXCASE and OXFALL use it to validate the use of fallthrough.
-       // - ONONAME uses it to store the current value of iota, see Node.Iota
+       // - Named OLITERALs use it to to store their ambient iota value.
        // Possibly still more uses. If you find any, document them.
        Xoffset int64
 

diff --git a/src/cmd/compile/internal/gc/typecheck.go b/src/cmd/compile/internal/gc/typecheck.go
index 1467189458b82a6a71370aea52c04d492ee6cfc6..51fc7fd442194d420a37e8c58eb3c793b54b7f21 100644 (file)
--- a/src/cmd/compile/internal/gc/typecheck.go
+++ b/src/cmd/compile/internal/gc/typecheck.go
@@ -36,8 +36,11 @@ func resolve(n *Node) *Node {
                if r != nil {
                        if r.Op != OIOTA {
                                n = r
-                       } else if n.Iota() >= 0 {
-                               n = nodintconst(n.Iota())
+                       } else if len(typecheckdefstack) > 0 {
+                               x := typecheckdefstack[len(typecheckdefstack)-1]
+                               if x.Op == OLITERAL {
+                                       n = nodintconst(x.Iota())
+                               }
                        }
                }
        }