[dev.regabi] cmd/compile: change ir.NameOffsetExpr to use *obj.LSym instead of *Name

Because NameOffsetExpr is always used with global variables, and SSA
backend only needs (*Name).Linksym() to generate value for them.

Passes toolstash -cmp.

Updates #43737

Change-Id: I17209e21383edb766070c0accd1fa4660659caef
Reviewed-on: https://go-review.googlesource.com/c/go/+/284119
Trust: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

diff --git a/src/cmd/compile/internal/ir/expr.go b/src/cmd/compile/internal/ir/expr.go
index e24b2d5b2cb41093dd637124f761e496a35d2243..a3356d432af2b60dd665a80a61dfa32ddf0efbe6 100644 (file)
--- a/src/cmd/compile/internal/ir/expr.go
+++ b/src/cmd/compile/internal/ir/expr.go
@@ -8,6 +8,7 @@ import (
        "bytes"
        "cmd/compile/internal/base"
        "cmd/compile/internal/types"
+       "cmd/internal/obj"
        "cmd/internal/src"
        "fmt"
        "go/constant"
@@ -461,22 +462,26 @@ func NewResultExpr(pos src.XPos, typ *types.Type, offset int64) *ResultExpr {
        return n
 }
 
-// A NameOffsetExpr refers to an offset within a variable.
+// A NameOffsetExpr refers to an offset within a global variable.
 // It is like a SelectorExpr but without the field name.
 type NameOffsetExpr struct {
        miniExpr
-       Name_   *Name
+       Linksym *obj.LSym
        Offset_ int64
 }
 
+func NewLinksymOffsetExpr(pos src.XPos, lsym *obj.LSym, offset int64, typ *types.Type) *NameOffsetExpr {
+       n := &NameOffsetExpr{Linksym: lsym, Offset_: offset}
+       n.typ = typ
+       n.op = ONAMEOFFSET
+       return n
+}
+
 func NewNameOffsetExpr(pos src.XPos, name *Name, offset int64, typ *types.Type) *NameOffsetExpr {
        if name == nil || IsBlank(name) || !(name.Op() == ONAME && name.Class == PEXTERN) {
                base.FatalfAt(pos, "cannot take offset of nil, blank name or non-global variable: %v", name)
        }
-       n := &NameOffsetExpr{Name_: name, Offset_: offset}
-       n.typ = typ
-       n.op = ONAMEOFFSET
-       return n
+       return NewLinksymOffsetExpr(pos, name.Linksym(), offset, typ)
 }
 
 // A SelectorExpr is a selector expression X.Sel.

diff --git a/src/cmd/compile/internal/ir/fmt.go b/src/cmd/compile/internal/ir/fmt.go
index a4e769f508b09de304569413532e2443d27aba14..dfb8e4227017015089b8649353357dc8b9e3812f 100644 (file)
--- a/src/cmd/compile/internal/ir/fmt.go
+++ b/src/cmd/compile/internal/ir/fmt.go
@@ -634,7 +634,7 @@ func exprFmt(n Node, s fmt.State, prec int) {
 
        case ONAMEOFFSET:
                n := n.(*NameOffsetExpr)
-               fmt.Fprintf(s, "(%v)(%v@%d)", n.Type(), n.Name_, n.Offset_)
+               fmt.Fprintf(s, "(%v)(%s@%d)", n.Type(), n.Linksym.Name, n.Offset_)
 
        case OTYPE:
                if n.Type() == nil && n.Sym() != nil {

diff --git a/src/cmd/compile/internal/ir/node_gen.go b/src/cmd/compile/internal/ir/node_gen.go
index f1b0a2162837304666e6089649399a6ffcba708b..7db9517b2c57a01c827976664e531852f1c8addd 100644 (file)
--- a/src/cmd/compile/internal/ir/node_gen.go
+++ b/src/cmd/compile/internal/ir/node_gen.go
@@ -825,16 +825,10 @@ func (n *NameOffsetExpr) doChildren(do func(Node) bool) bool {
        if doNodes(n.init, do) {
                return true
        }
-       if n.Name_ != nil && do(n.Name_) {
-               return true
-       }
        return false
 }
 func (n *NameOffsetExpr) editChildren(edit func(Node) Node) {
        editNodes(n.init, edit)
-       if n.Name_ != nil {
-               n.Name_ = edit(n.Name_).(*Name)
-       }
 }
 
 func (n *NilExpr) Format(s fmt.State, verb rune) { fmtNode(n, s, verb) }

diff --git a/src/cmd/compile/internal/ssagen/ssa.go b/src/cmd/compile/internal/ssagen/ssa.go
index 7726ecac557757a82cd86cf7524ce0f40b616e60..fce02f475a3ad31b8eeea1731c40ca19e26bf161 100644 (file)
--- a/src/cmd/compile/internal/ssagen/ssa.go
+++ b/src/cmd/compile/internal/ssagen/ssa.go
@@ -2257,15 +2257,10 @@ func (s *state) expr(n ir.Node) *ssa.Value {
                if s.canSSA(n) {
                        return s.variable(n, n.Type())
                }
-               addr := s.addr(n)
-               return s.load(n.Type(), addr)
+               return s.load(n.Type(), s.addr(n))
        case ir.ONAMEOFFSET:
                n := n.(*ir.NameOffsetExpr)
-               if s.canSSAName(n.Name_) && TypeOK(n.Type()) {
-                       return s.variable(n, n.Type())
-               }
-               addr := s.addr(n)
-               return s.load(n.Type(), addr)
+               return s.load(n.Type(), s.addr(n))
        case ir.ONIL:
                n := n.(*ir.NilExpr)
                t := n.Type()
@@ -5088,13 +5083,18 @@ func (s *state) addr(n ir.Node) *ssa.Value {
        }
 
        t := types.NewPtr(n.Type())
-       var offset int64
+       linksymOffset := func(lsym *obj.LSym, offset int64) *ssa.Value {
+               v := s.entryNewValue1A(ssa.OpAddr, t, lsym, s.sb)
+               // TODO: Make OpAddr use AuxInt as well as Aux.
+               if offset != 0 {
+                       v = s.entryNewValue1I(ssa.OpOffPtr, v.Type, offset, v)
+               }
+               return v
+       }
        switch n.Op() {
        case ir.ONAMEOFFSET:
                no := n.(*ir.NameOffsetExpr)
-               offset = no.Offset_
-               n = no.Name_
-               fallthrough
+               return linksymOffset(no.Linksym, no.Offset_)
        case ir.ONAME:
                n := n.(*ir.Name)
                if n.Heapaddr != nil {
@@ -5103,12 +5103,7 @@ func (s *state) addr(n ir.Node) *ssa.Value {
                switch n.Class {
                case ir.PEXTERN:
                        // global variable
-                       v := s.entryNewValue1A(ssa.OpAddr, t, n.Linksym(), s.sb)
-                       // TODO: Make OpAddr use AuxInt as well as Aux.
-                       if offset != 0 {
-                               v = s.entryNewValue1I(ssa.OpOffPtr, v.Type, offset, v)
-                       }
-                       return v
+                       return linksymOffset(n.Linksym(), 0)
                case ir.PPARAM:
                        // parameter slot
                        v := s.decladdrs[n]