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all: generate NOTOC shared code on power10/PPC64/linux
An explicit TOC pointer is not needed when building with GOPPC64=power10
on linux/PPC64 as all addressing is PC relative.
Apply changes to the compiler, assembler, and linker to remove R2/TOC
maintenance in these build configurations.
This results in noticeably smaller PIC binaries. For example the size
(in bytes) of the k8s binaries before and with this patch:
GOFLAGS="-buildmode=pie" \
FORCE_HOST_GO=y \
GOPPC64=power10 \
CGO_CFLAGS="-mcpu=power10 -O2 -g" \
make all
apiextensions-apiserver 66060288 64487424 -1572864 -2.38%
e2e_node.test 163520856 159850760 -3670096 -2.24%
e2e.test 178167304 174890432 -3276872 -1.83%
ginkgo 11010048 10747904 -262144 -2.38%
go-runner 2162688 2162688 0 0%
k8s-tests 170182216 166970880 -3211336 -1.88%
kubeadm 52625408 51314688 -1310720 -2.49%
kube-aggregator 62849024 61341696 -1507328 -2.39%
kube-apiserver 147783680 144375808 -3407872 -2.30%
kube-controller-manager 131137536 127991808 -3145728 -2.39%
kubectl 53608448 52363264 -1245184 -2.32%
kubectl-convert 52625408 51314688 -1310720 -2.49%
kubelet 120913920 118095872 -2818048 -2.33%
kube-log-runner 1900544 1835008 -65536 -3.44%
kubemark 119078912 116326400 -2752512 -2.31%
kube-proxy 58392576 56885248 -1507328 -2.58%
kube-scheduler 60751872 59244544 -1507328 -2.48%
mounter 1835008 1769472 -65536 -3.57%
watch-termination 38076416 37158912 -917504 -2.40%
And text size changes:
apiextensions-apiserver 30243288 28654116 -1589172 -5.25%
e2e_node.test 71132064 67520288 -3611776 -5.07%
e2e.test 61843984 58635088 -3208896 -5.18%
ginkgo 4975916 4769304 -206612 -4.15%
go-runner 896532 858400 -38132 -4.25%
k8s-tests 60925792 57752032 -3173760 -5.20%
kubeadm 24643240 23404100 -1239140 -5.02%
kube-aggregator 28688060 27160976 -1527084 -5.32%
kube-apiserver 65627332 62259460 -3367872 -5.13%
kube-controller-manager 56773844 53706532 -3067312 -5.40%
kubectl 24344276 23080640 -1263636 -5.19%
kubectl-convert 23733764 22521768 -1211996 -5.10%
kubelet 52494580 49720340 -2774240 -5.28%
kube-log-runner 787128 753232 -33896 -4.30%
kubemark 51576580 48837380 -2739200 -5.31%
kube-proxy 26541092 25124080 -1417012 -5.33%
kube-scheduler 27448512 25976172 -1472340 -5.36%
mounter 744100 712628 -31472 -4.22%
watch-termination 18047276 17139912 -907364 -5.02%
Change-Id: Ib4872823b06f93861e46a00679b5d4e5e30b538a
Reviewed-on: https://go-review.googlesource.com/c/go/+/495416
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Run-TryBot: Paul Murphy <murp@ibm.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>
This commit is contained in:
Paul E. Murphy
Paul Murphy
parent
1524bd1c78
commit
29d5272da8
@ -1869,7 +1869,7 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
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pp.To.Reg = ppc64.REG_LR
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pp.SetFrom3Const(1)
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if base.Ctxt.Flag_shared {
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if ppc64.NeedTOCpointer(base.Ctxt) {
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// When compiling Go into PIC, the function we just
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// called via pointer might have been implemented in
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// a separate module and so overwritten the TOC
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@ -1071,7 +1071,7 @@ func (c *ctxt9) aclass(a *obj.Addr) int {
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}
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case obj.TYPE_BRANCH:
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if a.Sym != nil && c.ctxt.Flag_dynlink {
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if a.Sym != nil && c.ctxt.Flag_dynlink && !pfxEnabled {
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return C_LBRAPIC
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}
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return C_SBRA
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@ -1275,6 +1275,12 @@ func opset(a, b0 obj.As) {
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oprange[a&obj.AMask] = oprange[b0]
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}
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// Determine if the build configuration requires a TOC pointer.
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// It is assumed this always called after buildop.
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func NeedTOCpointer(ctxt *obj.Link) bool {
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return !pfxEnabled && ctxt.Flag_shared
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}
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// Build the opcode table
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func buildop(ctxt *obj.Link) {
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// Limit PC-relative prefix instruction usage to supported and tested targets.
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@ -643,8 +643,8 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
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q = p
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if c.ctxt.Flag_shared && c.cursym.Name != "runtime.duffzero" && c.cursym.Name != "runtime.duffcopy" {
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// When compiling Go into PIC, all functions must start
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if NeedTOCpointer(c.ctxt) && c.cursym.Name != "runtime.duffzero" && c.cursym.Name != "runtime.duffcopy" {
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// When compiling Go into PIC, without PCrel support, all functions must start
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// with instructions to load the TOC pointer into r2:
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//
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// addis r2, r12, .TOC.-func@ha
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@ -763,7 +763,7 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
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break
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}
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if c.ctxt.Flag_shared {
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if NeedTOCpointer(c.ctxt) {
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q = obj.Appendp(q, c.newprog)
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q.As = AMOVD
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q.Pos = p.Pos
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@ -1289,7 +1289,7 @@ func (c *ctxt9) stacksplit(p *obj.Prog, framesize int32) *obj.Prog {
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morestacksym = c.ctxt.Lookup("runtime.morestack")
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}
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if c.ctxt.Flag_shared {
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if NeedTOCpointer(c.ctxt) {
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// In PPC64 PIC code, R2 is used as TOC pointer derived from R12
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// which is the address of function entry point when entering
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// the function. We need to preserve R2 across call to morestack.
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@ -1352,7 +1352,7 @@ func (c *ctxt9) stacksplit(p *obj.Prog, framesize int32) *obj.Prog {
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p.To.Sym = morestacksym
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}
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if c.ctxt.Flag_shared {
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if NeedTOCpointer(c.ctxt) {
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// MOVD 8(SP), R2
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p = obj.Appendp(p, c.newprog)
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p.As = AMOVD
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@ -137,14 +137,17 @@ func putelfsym(ctxt *Link, x loader.Sym, typ elf.SymType, curbind elf.SymBind) {
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// externally linking, I don't think this makes a lot of sense.
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other = int(elf.STV_HIDDEN)
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}
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if ctxt.IsPPC64() && typ == elf.STT_FUNC && ldr.AttrShared(x) && ldr.SymName(x) != "runtime.duffzero" && ldr.SymName(x) != "runtime.duffcopy" {
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// On ppc64 the top three bits of the st_other field indicate how
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// many instructions separate the global and local entry points. In
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// our case it is two instructions, indicated by the value 3.
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// The conditions here match those in preprocess in
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// cmd/internal/obj/ppc64/obj9.go, which is where the
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// instructions are inserted.
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other |= 3 << 5
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if ctxt.IsPPC64() && typ == elf.STT_FUNC && ldr.AttrShared(x) {
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// On ppc64 the top three bits of the st_other field indicate how many
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// bytes separate the global and local entry points. For non-PCrel shared
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// symbols this is always 8 bytes except for some special functions.
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hasPCrel := buildcfg.GOPPC64 >= 10 && buildcfg.GOOS == "linux"
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// This should match the preprocessing behavior in cmd/internal/obj/ppc64/obj9.go
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// where the distinct global entry is inserted.
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if !hasPCrel && ldr.SymName(x) != "runtime.duffzero" && ldr.SymName(x) != "runtime.duffcopy" {
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other |= 3 << 5
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}
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}
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// When dynamically linking, we create Symbols by reading the names from
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@ -221,10 +221,10 @@ func genpltstub(ctxt *ld.Link, ldr *loader.Loader, r loader.Reloc, ri int, s loa
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// An R_PPC64_REL24_NOTOC relocation does not use or maintain
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// a TOC pointer, and almost always implies a Power10 target.
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//
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// For dynamic calls made from a Go object, the shared attribute
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// indicates a PIC symbol, which requires a TOC pointer be
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// maintained. Otherwise, a simpler non-PIC stub suffices.
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if (r.Type() == objabi.ElfRelocOffset+objabi.RelocType(elf.R_PPC64_REL24)) || (!ldr.AttrExternal(s) && ldr.AttrShared(s)) {
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// For dynamic calls made from a Go caller, a TOC relative stub is
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// always needed when a TOC pointer is maintained (specifically, if
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// the Go caller is PIC, and cannot use PCrel instructions).
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if (r.Type() == objabi.ElfRelocOffset+objabi.RelocType(elf.R_PPC64_REL24)) || (!ldr.AttrExternal(s) && ldr.AttrShared(s) && !hasPCrel) {
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stubTypeStr = "_tocrel"
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stubType = 1
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} else {
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@ -318,7 +318,7 @@ func genstubs(ctxt *ld.Link, ldr *loader.Loader) {
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case sym.STEXT:
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targ := r.Sym()
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if (ldr.AttrExternal(targ) && ldr.SymLocalentry(targ) <= 1) || (!ldr.AttrExternal(targ) && !ldr.AttrShared(targ)) {
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if (ldr.AttrExternal(targ) && ldr.SymLocalentry(targ) <= 1) || (!ldr.AttrExternal(targ) && (!ldr.AttrShared(targ) || hasPCrel)) {
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// This is NOTOC to NOTOC call (st_other is 0 or 1). No call stub is needed.
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} else {
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// This is a NOTOC to TOC function. Generate a calling stub.
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@ -387,10 +387,12 @@ func genaddmoduledata(ctxt *ld.Link, ldr *loader.Loader) {
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// runtime.addmoduledata(local.moduledata)
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// }
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// Regenerate TOC from R12 (the address of this function).
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sz := initfunc.AddSymRef(ctxt.Arch, ctxt.DotTOC[0], 0, objabi.R_ADDRPOWER_PCREL, 8)
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initfunc.SetUint32(ctxt.Arch, sz-8, 0x3c4c0000) // addis r2, r12, .TOC.-func@ha
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initfunc.SetUint32(ctxt.Arch, sz-4, 0x38420000) // addi r2, r2, .TOC.-func@l
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if !hasPCrel {
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// Regenerate TOC from R12 (the address of this function).
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sz := initfunc.AddSymRef(ctxt.Arch, ctxt.DotTOC[0], 0, objabi.R_ADDRPOWER_PCREL, 8)
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initfunc.SetUint32(ctxt.Arch, sz-8, 0x3c4c0000) // addis r2, r12, .TOC.-func@ha
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initfunc.SetUint32(ctxt.Arch, sz-4, 0x38420000) // addi r2, r2, .TOC.-func@l
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}
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// This is Go ABI. Stack a frame and save LR.
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o(OP_MFLR_R0) // mflr r0
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@ -407,11 +409,11 @@ func genaddmoduledata(ctxt *ld.Link, ldr *loader.Loader) {
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}
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if !hasPCrel {
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sz = initfunc.AddSymRef(ctxt.Arch, tgt, 0, objabi.R_ADDRPOWER_GOT, 8)
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sz := initfunc.AddSymRef(ctxt.Arch, tgt, 0, objabi.R_ADDRPOWER_GOT, 8)
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initfunc.SetUint32(ctxt.Arch, sz-8, 0x3c620000) // addis r3, r2, local.moduledata@got@ha
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initfunc.SetUint32(ctxt.Arch, sz-4, 0xe8630000) // ld r3, local.moduledata@got@l(r3)
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} else {
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sz = initfunc.AddSymRef(ctxt.Arch, tgt, 0, objabi.R_ADDRPOWER_GOT_PCREL34, 8)
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sz := initfunc.AddSymRef(ctxt.Arch, tgt, 0, objabi.R_ADDRPOWER_GOT_PCREL34, 8)
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// Note, this is prefixed instruction. It must not cross a 64B boundary.
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// It is doubleworld aligned here, so it will never cross (this function is 16B aligned, minimum).
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initfunc.SetUint32(ctxt.Arch, sz-8, OP_PLD_PFX_PCREL)
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@ -419,7 +421,7 @@ func genaddmoduledata(ctxt *ld.Link, ldr *loader.Loader) {
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}
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// Call runtime.addmoduledata
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sz = initfunc.AddSymRef(ctxt.Arch, addmoduledata, 0, objabi.R_CALLPOWER, 4)
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sz := initfunc.AddSymRef(ctxt.Arch, addmoduledata, 0, objabi.R_CALLPOWER, 4)
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initfunc.SetUint32(ctxt.Arch, sz-4, OP_BL) // bl runtime.addmoduledata
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o(OP_NOP) // nop (for TOC restore)
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@ -995,7 +997,12 @@ func elfreloc1(ctxt *ld.Link, out *ld.OutBuf, ldr *loader.Loader, s loader.Sym,
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if r.Size != 4 {
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return false
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}
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out.Write64(uint64(elf.R_PPC64_REL24) | uint64(elfsym)<<32)
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if !hasPCrel {
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out.Write64(uint64(elf.R_PPC64_REL24) | uint64(elfsym)<<32)
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} else {
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// TOC is not used in PCrel compiled Go code.
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out.Write64(uint64(elf.R_PPC64_REL24_NOTOC) | uint64(elfsym)<<32)
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}
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}
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out.Write64(uint64(r.Xadd))
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@ -1441,10 +1448,10 @@ func archreloc(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, r loade
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tgtName := ldr.SymName(rs)
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// If we are linking PIE or shared code, all golang generated object files have an extra 2 instruction prologue
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// If we are linking PIE or shared code, non-PCrel golang generated object files have an extra 2 instruction prologue
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// to regenerate the TOC pointer from R12. The exception are two special case functions tested below. Note,
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// local call offsets for externally generated objects are accounted for when converting into golang relocs.
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if !ldr.AttrExternal(rs) && ldr.AttrShared(rs) && tgtName != "runtime.duffzero" && tgtName != "runtime.duffcopy" {
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if !hasPCrel && !ldr.AttrExternal(rs) && ldr.AttrShared(rs) && tgtName != "runtime.duffzero" && tgtName != "runtime.duffcopy" {
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// Furthermore, only apply the offset if the target looks like the start of a function call.
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if r.Add() == 0 && ldr.SymType(rs) == sym.STEXT {
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t += 8
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