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cmd/internal/obj/mips,s390x,riscv: save LR after decrementing SP

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Following CL 412474, for the rest of the LR architectures. On
MIPS(32/64), S390X, and RISCV, there is no single instruction that
saves the LR and decrements the SP, so we need to insert an
instruction to save the LR after decrementing the SP.

On ARM(32) and PPC64 we already use a single instruction to save
the LR and decrement the SP.

Updates #53374.

Change-Id: I5a2e211026d95edb0e0f7d084ddb784f8077b86d
Reviewed-on: https://go-review.googlesource.com/c/go/+/413428
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
This commit is contained in:
Cherry Mui 2022-06-22 16:28:41 -04:00 • committed by David Chase
parent d6481d5b96
commit 3562977b6f
4 changed files with 41 additions and 4 deletions
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14
src/cmd/internal/obj/mips/obj0.go
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@ -343,6 +343,20 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
q.Spadj = +autosize
q = c.ctxt.EndUnsafePoint(q, c.newprog, -1)
// On Linux, in a cgo binary we may get a SIGSETXID signal early on
// before the signal stack is set, as glibc doesn't allow us to block
// SIGSETXID. So a signal may land on the current stack and clobber
// the content below the SP. We store the LR again after the SP is
// decremented.
q = obj.Appendp(q, newprog)
q.As = mov
q.Pos = p.Pos
q.From.Type = obj.TYPE_REG
q.From.Reg = REGLINK
q.To.Type = obj.TYPE_MEM
q.To.Offset = 0
q.To.Reg = REGSP
}
if c.cursym.Func().Text.From.Sym.Wrapper() && c.cursym.Func().Text.Mark&LEAF == 0 {