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cmd/compile: request r12 for indirect calls on ppc64le

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On ppc64le, functions compiled with -shared expect r12 to
hold the function's address for indirect calls. Previously
this was enforced by generating a move instruction if the
address wasn't already in r12. This change avoids that extra
move by requesting r12 in the CALL ops that do indirect calls.

As a result of adding support for plugins on ppc64le, it was
discovered that there would be more cases where this extra
move was needed, so this seemed like a better solution.

Updates #20756

Change-Id: I6770885a46990f78c6d2902a715dcdaa822192a1
Reviewed-on: https://go-review.googlesource.com/62890
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This commit is contained in:
Lynn Boger 2017-09-11 10:39:24 -04:00
parent 818353022e
commit b74b43de68
4 changed files with 11 additions and 25 deletions
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8
src/cmd/compile/internal/ssa/regalloc.go
View file

@ -562,12 +562,6 @@ func (s *regAllocState) init(f *Func) {
if s.f.Config.ctxt.Framepointer_enabled && s.f.Config.FPReg >= 0 {
s.allocatable &^= 1 << uint(s.f.Config.FPReg)
}
if s.f.Config.ctxt.Flag_shared {
switch s.f.Config.arch {
case "ppc64le": // R2 already reserved.
s.allocatable &^= 1 << 12 // R12
}
}
if s.f.Config.LinkReg != -1 {
if isLeaf(f) {
// Leaf functions don't save/restore the link register.
@ -587,7 +581,7 @@ func (s *regAllocState) init(f *Func) {
case "arm":
s.allocatable &^= 1 << 9 // R9
case "ppc64le": // R2 already reserved.
s.allocatable &^= 1 << 12 // R12
// nothing to do
case "arm64":
// nothing to do?
case "386":