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cmd/link/internal/ppc64: Use PCrel relocs in runtime.addmoduledata if supported

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This is another step towards supporting TOC-free operations.

Change-Id: I77edcf066c757b8ec815c701d7f6d72cd645eca9
Reviewed-on: https://go-review.googlesource.com/c/go/+/483437
Reviewed-by: Bryan Mills <bcmills@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
Run-TryBot: Paul Murphy <murp@ibm.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
This commit is contained in:
Paul E. Murphy 2023-01-12 15:57:51 -06:00 committed by Paul Murphy
parent db32aba508
commit de788efeac
1 changed files with 40 additions and 37 deletions
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77
src/cmd/link/internal/ppc64/asm.go
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@ -219,20 +219,23 @@ func genaddmoduledata(ctxt *ld.Link, ldr *loader.Loader) {
initfunc.AddUint32(ctxt.Arch, op)
}
// addis r2, r12, .TOC.-func@ha
toc := ctxt.DotTOC[0]
rel1, _ := initfunc.AddRel(objabi.R_ADDRPOWER_PCREL)
rel1.SetOff(0)
rel1.SetSiz(8)
rel1.SetSym(toc)
o(0x3c4c0000)
// addi r2, r2, .TOC.-func@l
o(0x38420000)
// mflr r31
o(0x7c0802a6)
// stdu r31, -32(r1)
o(0xf801ffe1)
// addis r3, r2, local.moduledata@got@ha
// Write a function to load this module's local.moduledata. This is shared code.
//
// package link
// void addmoduledata() {
// runtime.addmoduledata(local.moduledata)
// }
// Regenerate TOC from R12 (the address of this function).
sz := initfunc.AddSymRef(ctxt.Arch, ctxt.DotTOC[0], 0, objabi.R_ADDRPOWER_PCREL, 8)
initfunc.SetUint32(ctxt.Arch, sz-8, 0x3c4c0000) // addis r2, r12, .TOC.-func@ha
initfunc.SetUint32(ctxt.Arch, sz-4, 0x38420000) // addi r2, r2, .TOC.-func@l
// This is Go ABI. Stack a frame and save LR.
o(0x7c0802a6) // mflr r31
o(0xf801ffe1) // stdu r31, -32(r1)
// Get the moduledata pointer from GOT and put into R3.
var tgt loader.Sym
if s := ldr.Lookup("local.moduledata", 0); s != 0 {
tgt = s
@ -241,29 +244,29 @@ func genaddmoduledata(ctxt *ld.Link, ldr *loader.Loader) {
} else {
tgt = ldr.LookupOrCreateSym("runtime.firstmoduledata", 0)
}
rel2, _ := initfunc.AddRel(objabi.R_ADDRPOWER_GOT)
rel2.SetOff(int32(initfunc.Size()))
rel2.SetSiz(8)
rel2.SetSym(tgt)
o(0x3c620000)
// ld r3, local.moduledata@got@l(r3)
o(0xe8630000)
// bl runtime.addmoduledata
rel3, _ := initfunc.AddRel(objabi.R_CALLPOWER)
rel3.SetOff(int32(initfunc.Size()))
rel3.SetSiz(4)
rel3.SetSym(addmoduledata)
o(0x48000001)
// nop
o(0x60000000)
// ld r31, 0(r1)
o(0xe8010000)
// mtlr r31
o(0x7c0803a6)
// addi r1,r1,32
o(0x38210020)
// blr
o(0x4e800020)
if !hasPCrel {
sz = initfunc.AddSymRef(ctxt.Arch, tgt, 0, objabi.R_ADDRPOWER_GOT, 8)
initfunc.SetUint32(ctxt.Arch, sz-8, 0x3c620000) // addis r3, r2, local.moduledata@got@ha
initfunc.SetUint32(ctxt.Arch, sz-4, 0xe8630000) // ld r3, local.moduledata@got@l(r3)
} else {
sz = initfunc.AddSymRef(ctxt.Arch, tgt, 0, objabi.R_ADDRPOWER_GOT_PCREL34, 8)
// Note, this is prefixed instruction. It must not cross a 64B boundary.
// It is doubleworld aligned here, so it will never cross (this function is 16B aligned, minimum).
initfunc.SetUint32(ctxt.Arch, sz-8, 0x04100000)
initfunc.SetUint32(ctxt.Arch, sz-4, 0xe4600000) // pld r3, local.moduledata@got@pcrel
}
// Call runtime.addmoduledata
sz = initfunc.AddSymRef(ctxt.Arch, addmoduledata, 0, objabi.R_CALLPOWER, 4)
initfunc.SetUint32(ctxt.Arch, sz-4, 0x48000001) // bl runtime.addmoduledata
o(0x60000000) // nop (for TOC restore)
// Pop stack frame and return.
o(0xe8010000) // ld r31, 0(r1)
o(0x7c0803a6) // mtlr r31
o(0x38210020) // addi r1,r1,32
o(0x4e800020) // blr
}
// Rewrite ELF (v1 or v2) calls to _savegpr0_n, _savegpr1_n, _savefpr_n, _restfpr_n, _savevr_m, or