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cmd/internal/obj/arm64: fix branch-too-far with TBZ like instructions

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The compiler now emits TBZ like instructions, but the assembler's
too-far-branch patch code didn't include that case. Add it.

Fixes #23889.

Change-Id: Ib75f9250c660b9fb652835fbc83263a5d5073dc5
Reviewed-on: https://go-review.googlesource.com/94902
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
This commit is contained in:
Cherry Zhang 2018-02-17 10:31:39 -05:00
parent 3c16934f16
commit 911839c1f4
2 changed files with 10 additions and 2 deletions
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11
src/cmd/internal/obj/arm64/asm7.go
View File

@ -728,9 +728,16 @@ func span7(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
o = c.oplook(p)
/* very large branches */
if (o.type_ == 7 || o.type_ == 39) && p.Pcond != nil { // 7: BEQ and like, 39: CBZ and like
if (o.type_ == 7 || o.type_ == 39 || o.type_ == 40) && p.Pcond != nil { // 7: BEQ and like, 39: CBZ and like, 40: TBZ and like
otxt := p.Pcond.Pc - pc
if otxt <= -(1<<18)+10 || otxt >= (1<<18)-10 {
var toofar bool
switch o.type_ {
case 7, 39: // branch instruction encodes 19 bits
toofar = otxt <= -(1<<20)+10 || otxt >= (1<<20)-10
case 40: // branch instruction encodes 14 bits
toofar = otxt <= -(1<<15)+10 || otxt >= (1<<15)-10
}
if toofar {
q := c.newprog()
q.Link = p.Link
p.Link = q

1
src/cmd/internal/obj/arm64/asm_test.go
View File

@ -52,6 +52,7 @@ func TestLarge(t *testing.T) {
// gen generates a very large program, with a very far conditional branch.
func gen(buf *bytes.Buffer) {
fmt.Fprintln(buf, "TEXT f(SB),0,$0-0")
fmt.Fprintln(buf, "TBZ $5, R0, label")
fmt.Fprintln(buf, "CBZ R0, label")
fmt.Fprintln(buf, "BEQ label")
for i := 0; i < 1<<19; i++ {