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| author | Michael Munday <mike.munday@ibm.com> | 2017-09-20 12:12:33 -0400 |
|---|---|---|
| committer | Michael Munday <mike.munday@ibm.com> | 2017-09-20 20:20:46 +0000 |
| commit | 55ac5b50b079b14bcab4dc1a971d84516cd4bf75 (patch) | |
| tree | 6facc9b7abb7f124f73be0b9b8656d8abdb921bf /src | |
| parent | 0d73f1e333bc9d0b0c07345efc498ebecaebf786 (diff) | |
| download | go-55ac5b50b079b14bcab4dc1a971d84516cd4bf75.tar.xz | |
cmd/compile: fix large global variables in -linkshared mode on s390x
When rewriting loads and stores accessing global variables to use the
GOT we were making use of REGTMP (R10). Unfortunately loads and stores
with large offsets (larger than 20-bits) were also using REGTMP,
causing it to be clobbered and subsequently a segmentation fault.
This can be fixed by using REGTMP2 (R11) for the rewrite. This is fine
because REGTMP2 only has a couple of uses in the assembler (division,
high multiplication and storage-to-storage instructions). We didn't
use REGTMP2 originally because it used to be used more frequently,
in particular for stores of constants to memory. However we have now
eliminated those uses.
This was found while writing a test case for CL 63030. That test case
is included in this CL.
Change-Id: I13956f1f3ca258a7c8a7ff0a7570d2848adf7f68
Reviewed-on: https://go-review.googlesource.com/65011
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Diffstat (limited to 'src')
| -rw-r--r-- | src/cmd/internal/obj/s390x/objz.go | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/src/cmd/internal/obj/s390x/objz.go b/src/cmd/internal/obj/s390x/objz.go index 1539de67c8..45ce68bebf 100644 --- a/src/cmd/internal/obj/s390x/objz.go +++ b/src/cmd/internal/obj/s390x/objz.go @@ -126,7 +126,7 @@ func (c *ctxtz) rewriteToUseGot(p *obj.Prog) { // ADD instruction. if p.From.Type == obj.TYPE_ADDR && p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local() { // MOVD $sym, Rx becomes MOVD sym@GOT, Rx - // MOVD $sym+<off>, Rx becomes MOVD sym@GOT, Rx; MOVD $<off>(Rx or REGTMP2), Rx + // MOVD $sym+<off>, Rx becomes MOVD sym@GOT, Rx or REGTMP2; MOVD $<off>(Rx or REGTMP2), Rx if p.To.Type != obj.TYPE_REG || p.As != AMOVD { c.ctxt.Diag("do not know how to handle LEA-type insn to non-register in %v with -dynlink", p) } @@ -154,8 +154,8 @@ func (c *ctxtz) rewriteToUseGot(p *obj.Prog) { c.ctxt.Diag("don't know how to handle %v with -dynlink", p) } var source *obj.Addr - // MOVD sym, Ry becomes MOVD sym@GOT, REGTMP; MOVD (REGTMP), Ry - // MOVD Ry, sym becomes MOVD sym@GOT, REGTMP; MOVD Ry, (REGTMP) + // MOVD sym, Ry becomes MOVD sym@GOT, REGTMP2; MOVD (REGTMP2), Ry + // MOVD Ry, sym becomes MOVD sym@GOT, REGTMP2; MOVD Ry, (REGTMP2) // An addition may be inserted between the two MOVs if there is an offset. if p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local() { if p.To.Name == obj.NAME_EXTERN && !p.To.Sym.Local() { @@ -184,17 +184,17 @@ func (c *ctxtz) rewriteToUseGot(p *obj.Prog) { p1.From.Sym = source.Sym p1.From.Name = obj.NAME_GOTREF p1.To.Type = obj.TYPE_REG - p1.To.Reg = REGTMP + p1.To.Reg = REGTMP2 p2.As = p.As p2.From = p.From p2.To = p.To if p.From.Name == obj.NAME_EXTERN { - p2.From.Reg = REGTMP + p2.From.Reg = REGTMP2 p2.From.Name = obj.NAME_NONE p2.From.Sym = nil } else if p.To.Name == obj.NAME_EXTERN { - p2.To.Reg = REGTMP + p2.To.Reg = REGTMP2 p2.To.Name = obj.NAME_NONE p2.To.Sym = nil } else { |