cmd/internal/obj: delete Debugzerostack dead code

Fixes #11060

Change-Id: I4c6647fc2f103015b67e30dc2cdb6f771526c139
Reviewed-on: https://go-review.googlesource.com/13840
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

diff --git a/src/cmd/internal/obj/arm/obj5.go b/src/cmd/internal/obj/arm/obj5.go
index 3ecf6bc9d536be4e1beceb9b36530f146147c0b4..ae1438f1035127d09a631a7159ff85a6e1a8ac1a 100644 (file)
--- a/src/cmd/internal/obj/arm/obj5.go
+++ b/src/cmd/internal/obj/arm/obj5.go
@@ -186,65 +186,6 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym) {
        cursym.Locals = autoffset
        cursym.Args = p.To.Val.(int32)
 
-       if ctxt.Debugzerostack != 0 {
-               if autoffset != 0 && p.From3.Offset&obj.NOSPLIT == 0 {
-                       // MOVW $4(R13), R1
-                       p = obj.Appendp(ctxt, p)
-
-                       p.As = AMOVW
-                       p.From.Type = obj.TYPE_ADDR
-                       p.From.Reg = REG_R13
-                       p.From.Offset = 4
-                       p.To.Type = obj.TYPE_REG
-                       p.To.Reg = REG_R1
-
-                       // MOVW $n(R13), R2
-                       p = obj.Appendp(ctxt, p)
-
-                       p.As = AMOVW
-                       p.From.Type = obj.TYPE_ADDR
-                       p.From.Reg = REG_R13
-                       p.From.Offset = 4 + int64(autoffset)
-                       p.To.Type = obj.TYPE_REG
-                       p.To.Reg = REG_R2
-
-                       // MOVW $0, R3
-                       p = obj.Appendp(ctxt, p)
-
-                       p.As = AMOVW
-                       p.From.Type = obj.TYPE_CONST
-                       p.From.Offset = 0
-                       p.To.Type = obj.TYPE_REG
-                       p.To.Reg = REG_R3
-
-                       // L:
-                       //      MOVW.nil R3, 0(R1) +4
-                       //      CMP R1, R2
-                       //      BNE L
-                       pl := obj.Appendp(ctxt, p)
-                       p := pl
-
-                       p.As = AMOVW
-                       p.From.Type = obj.TYPE_REG
-                       p.From.Reg = REG_R3
-                       p.To.Type = obj.TYPE_MEM
-                       p.To.Reg = REG_R1
-                       p.To.Offset = 4
-                       p.Scond |= C_PBIT
-
-                       p = obj.Appendp(ctxt, p)
-                       p.As = ACMP
-                       p.From.Type = obj.TYPE_REG
-                       p.From.Reg = REG_R1
-                       p.Reg = REG_R2
-
-                       p = obj.Appendp(ctxt, p)
-                       p.As = ABNE
-                       p.To.Type = obj.TYPE_BRANCH
-                       p.Pcond = pl
-               }
-       }
-
        /*
         * find leaf subroutines
         * strip NOPs

diff --git a/src/cmd/internal/obj/link.go b/src/cmd/internal/obj/link.go
index 3798e23333938271479306c41693f699ee9c1342..9404251c69709d2cb6c3abb11c9847d96b8ec05e 100644 (file)
--- a/src/cmd/internal/obj/link.go
+++ b/src/cmd/internal/obj/link.go
@@ -466,7 +466,6 @@ type Link struct {
        Arch               *LinkArch
        Debugasm           int32
        Debugvlog          int32
-       Debugzerostack     int32
        Debugdivmod        int32
        Debugpcln          int32
        Flag_shared        int32

diff --git a/src/cmd/internal/obj/x86/obj6.go b/src/cmd/internal/obj/x86/obj6.go
index fa9c474adb344f8f66089330bcd408e7a4b07ff8..e221bdab82b3b5f5bc69a8f87d70cd67a81cfcdc 100644 (file)
--- a/src/cmd/internal/obj/x86/obj6.go
+++ b/src/cmd/internal/obj/x86/obj6.go
@@ -657,51 +657,6 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym) {
                p2.Pcond = p
        }
 
-       if ctxt.Debugzerostack != 0 && autoffset != 0 && cursym.Text.From3.Offset&obj.NOSPLIT == 0 {
-               // 6l -Z means zero the stack frame on entry.
-               // This slows down function calls but can help avoid
-               // false positives in garbage collection.
-               p = obj.Appendp(ctxt, p)
-
-               p.As = AMOVQ
-               p.From.Type = obj.TYPE_REG
-               p.From.Reg = REG_SP
-               p.To.Type = obj.TYPE_REG
-               p.To.Reg = REG_DI
-               if p.Mode == 32 {
-                       p.As = AMOVL
-               }
-
-               p = obj.Appendp(ctxt, p)
-               p.As = AMOVQ
-               p.From.Type = obj.TYPE_CONST
-               p.From.Offset = int64(autoffset) / int64(ctxt.Arch.Regsize)
-               p.To.Type = obj.TYPE_REG
-               p.To.Reg = REG_CX
-               if p.Mode == 32 {
-                       p.As = AMOVL
-               }
-
-               p = obj.Appendp(ctxt, p)
-               p.As = AMOVQ
-               p.From.Type = obj.TYPE_CONST
-               p.From.Offset = 0
-               p.To.Type = obj.TYPE_REG
-               p.To.Reg = REG_AX
-               if p.Mode == 32 {
-                       p.As = AMOVL
-               }
-
-               p = obj.Appendp(ctxt, p)
-               p.As = AREP
-
-               p = obj.Appendp(ctxt, p)
-               p.As = ASTOSQ
-               if p.Mode == 32 {
-                       p.As = ASTOSL
-               }
-       }
-
        var a int
        var pcsize int
        for ; p != nil; p = p.Link {