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| author | Paul Murphy <murp@redhat.com> | 2025-10-08 14:34:09 -0500 |
|---|---|---|
| committer | Gopher Robot <gobot@golang.org> | 2025-10-21 07:41:30 -0700 |
| commit | 694182d77b1a0e3676214ad0e361bdbdafde33a1 (patch) | |
| tree | dc4c23077d1e46255003446cd847709e49d5bc54 /src/cmd/internal/obj | |
| parent | b0dcb955421e1fe8021dbe23b8dd8d2b184da395 (diff) | |
| download | go-694182d77b1a0e3676214ad0e361bdbdafde33a1.tar.xz | |
cmd/internal/obj/ppc64: improve large prologue generation
Avoid needing an unsafe section to store LR and adjust SP
for large constants by using the stdux (MOVDU) instruction.
This is also a few instructions shorter as the large
constant adjustment is only created once.
Change-Id: I6ff7a24181cdadb1846a33129fc148dcf59b76d5
Reviewed-on: https://go-review.googlesource.com/c/go/+/710197
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Auto-Submit: Keith Randall <khr@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Diffstat (limited to 'src/cmd/internal/obj')
| -rw-r--r-- | src/cmd/internal/obj/ppc64/obj9.go | 38 |
1 files changed, 16 insertions, 22 deletions
diff --git a/src/cmd/internal/obj/ppc64/obj9.go b/src/cmd/internal/obj/ppc64/obj9.go index 5615b70aad..bae2965639 100644 --- a/src/cmd/internal/obj/ppc64/obj9.go +++ b/src/cmd/internal/obj/ppc64/obj9.go @@ -903,44 +903,38 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) { q.To.Reg = REGSP q.Spadj = autosize } else { - // Frame size is too large for a MOVDU instruction. - // Store link register before decrementing SP, so if a signal comes - // during the execution of the function prologue, the traceback - // code will not see a half-updated stack frame. - // This sequence is not async preemptible, as if we open a frame - // at the current SP, it will clobber the saved LR. + // Frame size is too large for an stdu MOVDU instruction, use stdux MOVDU. q = obj.Appendp(q, c.newprog) q.As = AMOVD q.Pos = p.Pos q.From.Type = obj.TYPE_REG q.From.Reg = REG_LR q.To.Type = obj.TYPE_REG - q.To.Reg = REG_R29 // REGTMP may be used to synthesize large offset in the next instruction - - q = c.ctxt.StartUnsafePoint(q, c.newprog) + q.To.Reg = REG_R29 + // Create stack adjustment in REGTMP q = obj.Appendp(q, c.newprog) q.As = AMOVD q.Pos = p.Pos - q.From.Type = obj.TYPE_REG - q.From.Reg = REG_R29 - q.To.Type = obj.TYPE_MEM - q.To.Offset = int64(-autosize) - q.To.Reg = REGSP + q.From.Type = obj.TYPE_CONST + q.From.Offset = int64(-autosize) + q.To.Type = obj.TYPE_REG + q.To.Reg = REGTMP prologueEnd = q + // MOVDU R29, R31(R1) q = obj.Appendp(q, c.newprog) - q.As = AADD + q.As = AMOVDU q.Pos = p.Pos - q.From.Type = obj.TYPE_CONST - q.From.Offset = int64(-autosize) - q.To.Type = obj.TYPE_REG - q.To.Reg = REGSP - q.Spadj = +autosize - - q = c.ctxt.EndUnsafePoint(q, c.newprog, -1) + q.From.Type = obj.TYPE_REG + q.From.Reg = REG_R29 + q.To.Type = obj.TYPE_MEM + q.To.Reg = REGTMP + q.To.Index = REGSP + q.Spadj = autosize } + prologueEnd.Pos = prologueEnd.Pos.WithXlogue(src.PosPrologueEnd) } else if c.cursym.Func().Text.Mark&LEAF == 0 { // A very few functions that do not return to their caller |