cmd/internal/obj/arm64: rewrite branches that are too far

Fixes #12540.

Change-Id: I7893fdc023145b0aca4b4c7df7e08e47edcf5bba
Reviewed-on: https://go-review.googlesource.com/16902
Run-TryBot: Minux Ma <minux@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

diff --git a/src/cmd/internal/obj/arm64/asm7.go b/src/cmd/internal/obj/arm64/asm7.go
index ae596cfaa47ae73f18f7257dedfe9b5ad612688a..29effcb5f515c1d56e0ec01f92f2b1995a39f696 100644 (file)
--- a/src/cmd/internal/obj/arm64/asm7.go
+++ b/src/cmd/internal/obj/arm64/asm7.go
@@ -535,9 +535,9 @@ func span7(ctxt *obj.Link, cursym *obj.LSym) {
                buildop(ctxt)
        }
 
-       bflag := 0
-       c := int32(0)
-       p.Pc = int64(c)
+       bflag := 1
+       c := int64(0)
+       p.Pc = c
        var m int
        var o *Optab
        for p = p.Link; p != nil; p = p.Link {
@@ -545,7 +545,7 @@ func span7(ctxt *obj.Link, cursym *obj.LSym) {
                if p.As == ADWORD && (c&7) != 0 {
                        c += 4
                }
-               p.Pc = int64(c)
+               p.Pc = c
                o = oplook(ctxt, p)
                m = int(o.size)
                if m == 0 {
@@ -567,13 +567,13 @@ func span7(ctxt *obj.Link, cursym *obj.LSym) {
                if p.As == AB || p.As == obj.ARET || p.As == AERET { /* TODO: other unconditional operations */
                        checkpool(ctxt, p, 0)
                }
-               c += int32(m)
+               c += int64(m)
                if ctxt.Blitrl != nil {
                        checkpool(ctxt, p, 1)
                }
        }
 
-       cursym.Size = int64(c)
+       cursym.Size = c
 
        /*
         * if any procedure is large enough to
@@ -582,38 +582,38 @@ func span7(ctxt *obj.Link, cursym *obj.LSym) {
         * around jmps to fix. this is rare.
         */
        for bflag != 0 {
+               if ctxt.Debugvlog != 0 {
+                       fmt.Fprintf(ctxt.Bso, "%5.2f span1\n", obj.Cputime())
+               }
                bflag = 0
                c = 0
-               for p = cursym.Text; p != nil; p = p.Link {
+               for p = cursym.Text.Link; p != nil; p = p.Link {
                        if p.As == ADWORD && (c&7) != 0 {
                                c += 4
                        }
-                       p.Pc = int64(c)
+                       p.Pc = c
                        o = oplook(ctxt, p)
 
-                       /* very large branches
-                       if(o->type == 6 && p->cond) {
-                               otxt = p->cond->pc - c;
-                               if(otxt < 0)
-                                       otxt = -otxt;
-                               if(otxt >= (1L<<17) - 10) {
-                                       q = ctxt->arch->prg();
-                                       q->link = p->link;
-                                       p->link = q;
-                                       q->as = AB;
-                                       q->to.type = obj.TYPE_BRANCH;
-                                       q->cond = p->cond;
-                                       p->cond = q;
-                                       q = ctxt->arch->prg();
-                                       q->link = p->link;
-                                       p->link = q;
-                                       q->as = AB;
-                                       q->to.type = obj.TYPE_BRANCH;
-                                       q->cond = q->link->link;
-                                       bflag = 1;
+                       /* very large branches */
+                       if o.type_ == 7 && p.Pcond != nil {
+                               otxt := p.Pcond.Pc - c
+                               if otxt <= -(1<<18)+10 || otxt >= (1<<18)-10 {
+                                       q := ctxt.NewProg()
+                                       q.Link = p.Link
+                                       p.Link = q
+                                       q.As = AB
+                                       q.To.Type = obj.TYPE_BRANCH
+                                       q.Pcond = p.Pcond
+                                       p.Pcond = q
+                                       q = ctxt.NewProg()
+                                       q.Link = p.Link
+                                       p.Link = q
+                                       q.As = AB
+                                       q.To.Type = obj.TYPE_BRANCH
+                                       q.Pcond = q.Link.Link
+                                       bflag = 1
                                }
                        }
-                       */
                        m = int(o.size)
 
                        if m == 0 {
@@ -623,12 +623,12 @@ func span7(ctxt *obj.Link, cursym *obj.LSym) {
                                continue
                        }
 
-                       c += int32(m)
+                       c += int64(m)
                }
        }
 
        c += -c & (FuncAlign - 1)
-       cursym.Size = int64(c)
+       cursym.Size = c
 
        /*
         * lay out the code, emitting code and data relocations.