cmd/compile/internal/types: remove unused lineno arguments for PushDcl/MarkDcl

More steps towards simpler symbol handling:

- Pushdcl's incoming pos argument, saved in a newly pushed *Sym, was always
  immediately overwritten by the Lastlineno value of the saved *Sym.

- Markdcl's incoming pos argument, saved in the stack mark *Sym, was not
  restored when the stack mark was popped.

- Popdcl always maintained the most recent Lastlineno for a *Sym given
  by package and name, making it unnecessary to save Lastlineno in the
  first place. Removed Lastlineno from the set of fields that need saving,
  and simplified Popdcl.

Change-Id: Ie93da1fbd780dcafc2703044e781c0c6298df569
Reviewed-on: https://go-review.googlesource.com/41390
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

diff --git a/src/cmd/compile/internal/gc/alg.go b/src/cmd/compile/internal/gc/alg.go
index fada9a115b42df16006b08a2be395365fb4b16de..c410a8da2ef60eacab3c0265179470ce31df28df 100644 (file)
--- a/src/cmd/compile/internal/gc/alg.go
+++ b/src/cmd/compile/internal/gc/alg.go
@@ -191,7 +191,7 @@ func genhash(sym *types.Sym, t *types.Type) {
 
        lineno = autogeneratedPos // less confusing than end of input
        dclcontext = PEXTERN
-       types.Markdcl(lineno)
+       types.Markdcl()
 
        // func sym(p *T, h uintptr) uintptr
        tfn := nod(OTFUNC, nil, nil)
@@ -362,7 +362,7 @@ func geneq(sym *types.Sym, t *types.Type) {
 
        lineno = autogeneratedPos // less confusing than end of input
        dclcontext = PEXTERN
-       types.Markdcl(lineno)
+       types.Markdcl()
 
        // func sym(p, q *T) bool
        tfn := nod(OTFUNC, nil, nil)

diff --git a/src/cmd/compile/internal/gc/bimport.go b/src/cmd/compile/internal/gc/bimport.go
index baae4bdd9ab037404734f207ad3a6267094a33f2..7766a5617a54363a71a93f88dea8b1c1e40592ca 100644 (file)
--- a/src/cmd/compile/internal/gc/bimport.go
+++ b/src/cmd/compile/internal/gc/bimport.go
@@ -1091,7 +1091,7 @@ func (p *importer) node() *Node {
                return nodl(p.pos(), op, p.expr(), nil)
 
        case OIF:
-               types.Markdcl(lineno)
+               types.Markdcl()
                n := nodl(p.pos(), OIF, nil, nil)
                n.Ninit.Set(p.stmtList())
                n.Left = p.expr()
@@ -1101,7 +1101,7 @@ func (p *importer) node() *Node {
                return n
 
        case OFOR:
-               types.Markdcl(lineno)
+               types.Markdcl()
                n := nodl(p.pos(), OFOR, nil, nil)
                n.Ninit.Set(p.stmtList())
                n.Left, n.Right = p.exprsOrNil()
@@ -1110,7 +1110,7 @@ func (p *importer) node() *Node {
                return n
 
        case ORANGE:
-               types.Markdcl(lineno)
+               types.Markdcl()
                n := nodl(p.pos(), ORANGE, nil, nil)
                n.List.Set(p.stmtList())
                n.Right = p.expr()
@@ -1119,7 +1119,7 @@ func (p *importer) node() *Node {
                return n
 
        case OSELECT, OSWITCH:
-               types.Markdcl(lineno)
+               types.Markdcl()
                n := nodl(p.pos(), op, nil, nil)
                n.Ninit.Set(p.stmtList())
                n.Left, _ = p.exprsOrNil()
@@ -1131,7 +1131,7 @@ func (p *importer) node() *Node {
        //      unreachable - mapped to OXCASE case below by exporter
 
        case OXCASE:
-               types.Markdcl(lineno)
+               types.Markdcl()
                n := nodl(p.pos(), OXCASE, nil, nil)
                n.Xoffset = int64(types.Block)
                n.List.Set(p.exprList())

diff --git a/src/cmd/compile/internal/gc/dcl.go b/src/cmd/compile/internal/gc/dcl.go
index 93f52f3af2a41f6f37b8b607c149befe152e335b..99e05e79b18052358fd62b1fdf07861acf78f63b 100644 (file)
--- a/src/cmd/compile/internal/gc/dcl.go
+++ b/src/cmd/compile/internal/gc/dcl.go
@@ -104,7 +104,7 @@ func declare(n *Node, ctxt Class) {
                        vargen++
                        gen = vargen
                }
-               types.Pushdcl(s, lineno)
+               types.Pushdcl(s)
                n.Name.Curfn = Curfn
        }
 
@@ -510,7 +510,7 @@ var funcdepth int32   // len(funcstack) during parsing, but then forced to be th
 // start the function.
 // called before funcargs; undone at end of funcbody.
 func funcstart(n *Node) {
-       types.Markdcl(lineno)
+       types.Markdcl()
        funcstack = append(funcstack, Curfn)
        funcdepth++
        Curfn = n

diff --git a/src/cmd/compile/internal/gc/noder.go b/src/cmd/compile/internal/gc/noder.go
index f0c501b1557053a929cb3ac0d4fa4a1a97e1a3a6..d4c00c80426fb1f51ca99cf963923620f173d785 100644 (file)
--- a/src/cmd/compile/internal/gc/noder.go
+++ b/src/cmd/compile/internal/gc/noder.go
@@ -774,14 +774,14 @@ func (p *noder) stmt(stmt syntax.Stmt) *Node {
 }
 
 func (p *noder) blockStmt(stmt *syntax.BlockStmt) []*Node {
-       types.Markdcl(lineno)
+       types.Markdcl()
        nodes := p.stmts(stmt.List)
        types.Popdcl()
        return nodes
 }
 
 func (p *noder) ifStmt(stmt *syntax.IfStmt) *Node {
-       types.Markdcl(lineno)
+       types.Markdcl()
        n := p.nod(stmt, OIF, nil, nil)
        if stmt.Init != nil {
                n.Ninit.Set1(p.stmt(stmt.Init))
@@ -803,7 +803,7 @@ func (p *noder) ifStmt(stmt *syntax.IfStmt) *Node {
 }
 
 func (p *noder) forStmt(stmt *syntax.ForStmt) *Node {
-       types.Markdcl(lineno)
+       types.Markdcl()
        var n *Node
        if r, ok := stmt.Init.(*syntax.RangeClause); ok {
                if stmt.Cond != nil || stmt.Post != nil {
@@ -837,7 +837,7 @@ func (p *noder) forStmt(stmt *syntax.ForStmt) *Node {
 }
 
 func (p *noder) switchStmt(stmt *syntax.SwitchStmt) *Node {
-       types.Markdcl(lineno)
+       types.Markdcl()
        n := p.nod(stmt, OSWITCH, nil, nil)
        if stmt.Init != nil {
                n.Ninit.Set1(p.stmt(stmt.Init))
@@ -861,7 +861,7 @@ func (p *noder) caseClauses(clauses []*syntax.CaseClause, tswitch *Node) []*Node
        var nodes []*Node
        for _, clause := range clauses {
                p.lineno(clause)
-               types.Markdcl(lineno)
+               types.Markdcl()
                n := p.nod(clause, OXCASE, nil, nil)
                if clause.Cases != nil {
                        n.List.Set(p.exprList(clause.Cases))
@@ -891,7 +891,7 @@ func (p *noder) commClauses(clauses []*syntax.CommClause) []*Node {
        var nodes []*Node
        for _, clause := range clauses {
                p.lineno(clause)
-               types.Markdcl(lineno)
+               types.Markdcl()
                n := p.nod(clause, OXCASE, nil, nil)
                if clause.Comm != nil {
                        n.List.Set1(p.stmt(clause.Comm))

diff --git a/src/cmd/compile/internal/gc/subr.go b/src/cmd/compile/internal/gc/subr.go
index 1d94147230123fa197f6d929314605df88d8e08d..fad935e92b8661a5fafa43a89301d319ed7b2175 100644 (file)
--- a/src/cmd/compile/internal/gc/subr.go
+++ b/src/cmd/compile/internal/gc/subr.go
@@ -1684,7 +1684,7 @@ func genwrapper(rcvr *types.Type, method *types.Field, newnam *types.Sym, iface
        lineno = autogeneratedPos
 
        dclcontext = PEXTERN
-       types.Markdcl(lineno)
+       types.Markdcl()
 
        this := namedfield(".this", rcvr)
        this.Left.Name.Param.Ntype = this.Right

diff --git a/src/cmd/compile/internal/types/scope.go b/src/cmd/compile/internal/types/scope.go
index 80e87eb4868877e410a9c606467e0ecade745fcf..64b1b181413ff20119b8e60a98174fd9b7c06440 100644 (file)
--- a/src/cmd/compile/internal/types/scope.go
+++ b/src/cmd/compile/internal/types/scope.go
@@ -4,15 +4,13 @@
 
 package types
 
-import "cmd/internal/src"
-
 // Declaration stack & operations
 
 var blockgen int32 = 1 // max block number
 var Block int32        // current block number
 
 // dclstack maintains a stack of shadowed symbol declarations so that
-// popdcl can restore their declarations when a block scope ends.
+// Popdcl can restore their declarations when a block scope ends.
 //
 // The Syms on this stack are not "real" Syms as they don't actually
 // represent object names. Sym is just a convenient type for saving shadowed
@@ -24,52 +22,39 @@ func dcopy(a, b *Sym) {
        a.Name = b.Name
        a.Def = b.Def
        a.Block = b.Block
-       a.Lastlineno = b.Lastlineno
 }
 
-func push(pos src.XPos) *Sym {
+func push() *Sym {
        d := new(Sym)
-       d.Lastlineno = pos
        dclstack = append(dclstack, d)
        return d
 }
 
 // Pushdcl pushes the current declaration for symbol s (if any) so that
 // it can be shadowed by a new declaration within a nested block scope.
-func Pushdcl(s *Sym, pos src.XPos) {
-       d := push(pos)
-       dcopy(d, s)
+func Pushdcl(s *Sym) {
+       dcopy(push(), s)
 }
 
 // Popdcl pops the innermost block scope and restores all symbol declarations
 // to their previous state.
 func Popdcl() {
-       i := len(dclstack)
-       for ; i > 0; i-- {
+       for i := len(dclstack); i > 0; i-- {
                d := dclstack[i-1]
                if d.Name == "" {
-                       break
+                       // pop stack mark
+                       Block = d.Block
+                       dclstack = dclstack[:i-1]
+                       return
                }
-               s := d.Pkg.Lookup(d.Name)
-               lno := s.Lastlineno
-               dcopy(s, d)
-               d.Lastlineno = lno
-       }
-
-       if i == 0 {
-               Fatalf("popdcl: no mark")
+               dcopy(d.Pkg.Lookup(d.Name), d)
        }
-
-       Block = dclstack[i-1].Block
-       dclstack = dclstack[:i-1] // pop mark
+       Fatalf("popdcl: no stack mark")
 }
 
 // Markdcl records the start of a new block scope for declarations.
-func Markdcl(lineno src.XPos) {
-       d := push(lineno)
-       d.Name = "" // used as stack mark
-       d.Block = Block
-
+func Markdcl() {
+       push().Block = Block // stack mark (Name == "")
        blockgen++
        Block = blockgen
 }

diff --git a/src/cmd/compile/internal/types/sym.go b/src/cmd/compile/internal/types/sym.go
index c969f96b47ece7aebdae130c11761a9519f374c4..e316e99ce7889de367cbb044c14eb8e60768e7f3 100644 (file)
--- a/src/cmd/compile/internal/types/sym.go
+++ b/src/cmd/compile/internal/types/sym.go
@@ -18,15 +18,15 @@ import (
 // allows using Sym pointer equality to test for Go identifier uniqueness when
 // handling selector expressions.
 type Sym struct {
-       Importdef *Pkg   // where imported definition was found
-       Linkname  string // link name
+       Importdef  *Pkg     // where imported definition was found
+       Linkname   string   // link name
+       Lastlineno src.XPos // last declaration for diagnostic
 
        // saved and restored by dcopy
-       Pkg        *Pkg
-       Name       string   // object name
-       Def        *Node    // definition: ONAME OTYPE OPACK or OLITERAL
-       Lastlineno src.XPos // last declaration for diagnostic
-       Block      int32    // blocknumber to catch redeclaration
+       Pkg   *Pkg
+       Name  string // object name
+       Def   *Node  // definition: ONAME OTYPE OPACK or OLITERAL
+       Block int32  // blocknumber to catch redeclaration
 
        flags   bitset8
        Label   *Node // corresponding label (ephemeral)