cmd/compile: eliminate stkdelta

At this point in the compiler we haven't assigned Xoffset values for
PAUTO variables anyway, so just immediately store the stack offsets
into Xoffset rather than into a global map.

Change-Id: I61eb471c857c8b145fd0895cbd98fd4e8d3c3365
Reviewed-on: https://go-review.googlesource.com/30081
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

diff --git a/src/cmd/compile/internal/gc/fmt.go b/src/cmd/compile/internal/gc/fmt.go
index 3b746344e658064351e685eec0e4c2bea6c57104..1fa718270581c7f8a28a20371658e8a9b51bfdaf 100644 (file)
--- a/src/cmd/compile/internal/gc/fmt.go
+++ b/src/cmd/compile/internal/gc/fmt.go
@@ -286,7 +286,7 @@ func (n *Node) jconv(s fmt.State, flag FmtFlag) {
        }
 
        if c == 0 && n.Xoffset != BADWIDTH {
-               fmt.Fprintf(s, " x(%d%+d)", n.Xoffset, stkdelta[n])
+               fmt.Fprintf(s, " x(%d)", n.Xoffset)
        }
 
        if n.Class != 0 {

diff --git a/src/cmd/compile/internal/gc/gsubr.go b/src/cmd/compile/internal/gc/gsubr.go
index 35f96270d8468c7a1edf9a9aba745f8c9def430b..b4051fa52d0c7dcecca825d1dd870458e5a2f92c 100644 (file)
--- a/src/cmd/compile/internal/gc/gsubr.go
+++ b/src/cmd/compile/internal/gc/gsubr.go
@@ -98,11 +98,11 @@ func fixautoused(p *obj.Prog) {
                }
 
                if p.From.Name == obj.NAME_AUTO && p.From.Node != nil {
-                       p.From.Offset += stkdelta[p.From.Node.(*Node)]
+                       p.From.Offset += p.From.Node.(*Node).Xoffset
                }
 
                if p.To.Name == obj.NAME_AUTO && p.To.Node != nil {
-                       p.To.Offset += stkdelta[p.To.Node.(*Node)]
+                       p.To.Offset += p.To.Node.(*Node).Xoffset
                }
 
                lp = &p.Link

diff --git a/src/cmd/compile/internal/gc/pgen.go b/src/cmd/compile/internal/gc/pgen.go
index 9b7cd6ba822859a2705a4bff22d46c459642cdb8..9d977e2fc509435f4ab96ebacf75dd38ff193d3f 100644 (file)
--- a/src/cmd/compile/internal/gc/pgen.go
+++ b/src/cmd/compile/internal/gc/pgen.go
@@ -214,11 +214,6 @@ func (s byStackVar) Len() int           { return len(s) }
 func (s byStackVar) Less(i, j int) bool { return cmpstackvarlt(s[i], s[j]) }
 func (s byStackVar) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
 
-// stkdelta records the stack offset delta for a node
-// during the compaction of the stack frame to remove
-// unused stack slots.
-var stkdelta = map[*Node]int64{}
-
 // TODO(lvd) find out where the PAUTO/OLITERAL nodes come from.
 func allocauto(ptxt *obj.Prog) {
        Stksize = 0
@@ -282,22 +277,13 @@ func allocauto(ptxt *obj.Prog) {
                        yyerror("stack frame too large (>2GB)")
                }
 
-               stkdelta[n] = -Stksize - n.Xoffset
+               n.Xoffset = -Stksize
        }
 
        Stksize = Rnd(Stksize, int64(Widthreg))
        stkptrsize = Rnd(stkptrsize, int64(Widthreg))
 
        fixautoused(ptxt)
-
-       // The debug information needs accurate offsets on the symbols.
-       for _, ln := range Curfn.Func.Dcl {
-               if ln.Class != PAUTO || ln.Op != ONAME {
-                       continue
-               }
-               ln.Xoffset += stkdelta[ln]
-               delete(stkdelta, ln)
-       }
 }
 
 func compile(fn *Node) {

diff --git a/src/cmd/compile/internal/gc/ssa.go b/src/cmd/compile/internal/gc/ssa.go
index a7a7de04c84947f24e0597397706e3400d8e84c3..f5e1c5f0c73a19236e9483b0932cf660393724bc 100644 (file)
--- a/src/cmd/compile/internal/gc/ssa.go
+++ b/src/cmd/compile/internal/gc/ssa.go
@@ -4374,12 +4374,13 @@ func AddAux2(a *obj.Addr, v *ssa.Value, offset int64) {
                a.Name = obj.NAME_PARAM
                a.Node = n
                a.Sym = Linksym(n.Orig.Sym)
-               a.Offset += n.Xoffset // TODO: why do I have to add this here?  I don't for auto variables.
+               a.Offset += n.Xoffset
        case *ssa.AutoSymbol:
                n := sym.Node.(*Node)
                a.Name = obj.NAME_AUTO
                a.Node = n
                a.Sym = Linksym(n.Sym)
+               // TODO: a.Offset += n.Xoffset once frame offsets for autos are computed during SSA
        default:
                v.Fatalf("aux in %s not implemented %#v", v, v.Aux)
        }