| From 41b90ed7af10a071ccfeede6a429e0d80518436d Mon Sep 17 00:00:00 2001 |
| From: Cherry Zhang <cherryyz@google.com> |
| Date: Sat, 17 Feb 2018 10:31:39 -0500 |
| Subject: [PATCH 8/9] cmd/internal/obj/arm64: fix branch-too-far with TBZ like |
| instructions |
| |
| 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 |
| --- |
| Signed-off-by: Khem Raj <raj.khem@gmail.com> |
| Upstream-Status: Backport |
| |
| src/cmd/internal/obj/arm64/asm7.go | 11 +++++++++-- |
| src/cmd/internal/obj/arm64/asm_test.go | 1 + |
| 2 files changed, 10 insertions(+), 2 deletions(-) |
| |
| diff --git a/src/cmd/internal/obj/arm64/asm7.go b/src/cmd/internal/obj/arm64/asm7.go |
| index ca81238c93..b1ee552489 100644 |
| --- a/src/cmd/internal/obj/arm64/asm7.go |
| +++ b/src/cmd/internal/obj/arm64/asm7.go |
| @@ -696,9 +696,16 @@ 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 |
| diff --git a/src/cmd/internal/obj/arm64/asm_test.go b/src/cmd/internal/obj/arm64/asm_test.go |
| index 369c48f510..3e0c9c13a6 100644 |
| --- a/src/cmd/internal/obj/arm64/asm_test.go |
| +++ b/src/cmd/internal/obj/arm64/asm_test.go |
| @@ -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++ { |
| -- |
| 2.14.1 |
| |