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-rw-r--r--src/cmd/link/internal/arm/asm.go657
1 files changed, 657 insertions, 0 deletions
diff --git a/src/cmd/link/internal/arm/asm.go b/src/cmd/link/internal/arm/asm.go
new file mode 100644
index 0000000..03caeae
--- /dev/null
+++ b/src/cmd/link/internal/arm/asm.go
@@ -0,0 +1,657 @@
+// Inferno utils/5l/asm.c
+// https://bitbucket.org/inferno-os/inferno-os/src/master/utils/5l/asm.c
+//
+// Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved.
+// Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
+// Portions Copyright © 1997-1999 Vita Nuova Limited
+// Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
+// Portions Copyright © 2004,2006 Bruce Ellis
+// Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
+// Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
+// Portions Copyright © 2009 The Go Authors. All rights reserved.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package arm
+
+import (
+ "cmd/internal/objabi"
+ "cmd/internal/sys"
+ "cmd/link/internal/ld"
+ "cmd/link/internal/loader"
+ "cmd/link/internal/sym"
+ "debug/elf"
+ "fmt"
+ "log"
+)
+
+// This assembler:
+//
+// .align 2
+// local.dso_init:
+// ldr r0, .Lmoduledata
+// .Lloadfrom:
+// ldr r0, [r0]
+// b runtime.addmoduledata@plt
+// .align 2
+// .Lmoduledata:
+// .word local.moduledata(GOT_PREL) + (. - (.Lloadfrom + 4))
+// assembles to:
+//
+// 00000000 <local.dso_init>:
+// 0: e59f0004 ldr r0, [pc, #4] ; c <local.dso_init+0xc>
+// 4: e5900000 ldr r0, [r0]
+// 8: eafffffe b 0 <runtime.addmoduledata>
+// 8: R_ARM_JUMP24 runtime.addmoduledata
+// c: 00000004 .word 0x00000004
+// c: R_ARM_GOT_PREL local.moduledata
+
+func gentext(ctxt *ld.Link, ldr *loader.Loader) {
+ initfunc, addmoduledata := ld.PrepareAddmoduledata(ctxt)
+ if initfunc == nil {
+ return
+ }
+
+ o := func(op uint32) {
+ initfunc.AddUint32(ctxt.Arch, op)
+ }
+ o(0xe59f0004)
+ o(0xe08f0000)
+
+ o(0xeafffffe)
+ rel, _ := initfunc.AddRel(objabi.R_CALLARM)
+ rel.SetOff(8)
+ rel.SetSiz(4)
+ rel.SetSym(addmoduledata)
+ rel.SetAdd(0xeafffffe) // vomit
+
+ o(0x00000000)
+
+ rel2, _ := initfunc.AddRel(objabi.R_PCREL)
+ rel2.SetOff(12)
+ rel2.SetSiz(4)
+ rel2.SetSym(ctxt.Moduledata)
+ rel2.SetAdd(4)
+}
+
+// Preserve highest 8 bits of a, and do addition to lower 24-bit
+// of a and b; used to adjust ARM branch instruction's target
+func braddoff(a int32, b int32) int32 {
+ return int32((uint32(a))&0xff000000 | 0x00ffffff&uint32(a+b))
+}
+
+func adddynrel(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loader.Sym, r loader.Reloc, rIdx int) bool {
+
+ targ := r.Sym()
+ var targType sym.SymKind
+ if targ != 0 {
+ targType = ldr.SymType(targ)
+ }
+
+ switch r.Type() {
+ default:
+ if r.Type() >= objabi.ElfRelocOffset {
+ ldr.Errorf(s, "unexpected relocation type %d (%s)", r.Type(), sym.RelocName(target.Arch, r.Type()))
+ return false
+ }
+
+ // Handle relocations found in ELF object files.
+ case objabi.ElfRelocOffset + objabi.RelocType(elf.R_ARM_PLT32):
+ su := ldr.MakeSymbolUpdater(s)
+ su.SetRelocType(rIdx, objabi.R_CALLARM)
+
+ if targType == sym.SDYNIMPORT {
+ addpltsym(target, ldr, syms, targ)
+ su.SetRelocSym(rIdx, syms.PLT)
+ su.SetRelocAdd(rIdx, int64(braddoff(int32(r.Add()), ldr.SymPlt(targ)/4)))
+ }
+
+ return true
+
+ case objabi.ElfRelocOffset + objabi.RelocType(elf.R_ARM_THM_PC22): // R_ARM_THM_CALL
+ ld.Exitf("R_ARM_THM_CALL, are you using -marm?")
+ return false
+
+ case objabi.ElfRelocOffset + objabi.RelocType(elf.R_ARM_GOT32): // R_ARM_GOT_BREL
+ if targType != sym.SDYNIMPORT {
+ addgotsyminternal(target, ldr, syms, targ)
+ } else {
+ ld.AddGotSym(target, ldr, syms, targ, uint32(elf.R_ARM_GLOB_DAT))
+ }
+
+ su := ldr.MakeSymbolUpdater(s)
+ su.SetRelocType(rIdx, objabi.R_CONST) // write r->add during relocsym
+ su.SetRelocSym(rIdx, 0)
+ su.SetRelocAdd(rIdx, r.Add()+int64(ldr.SymGot(targ)))
+ return true
+
+ case objabi.ElfRelocOffset + objabi.RelocType(elf.R_ARM_GOT_PREL): // GOT(nil) + A - nil
+ if targType != sym.SDYNIMPORT {
+ addgotsyminternal(target, ldr, syms, targ)
+ } else {
+ ld.AddGotSym(target, ldr, syms, targ, uint32(elf.R_ARM_GLOB_DAT))
+ }
+ su := ldr.MakeSymbolUpdater(s)
+ su.SetRelocType(rIdx, objabi.R_PCREL)
+ su.SetRelocSym(rIdx, syms.GOT)
+ su.SetRelocAdd(rIdx, r.Add()+4+int64(ldr.SymGot(targ)))
+ return true
+
+ case objabi.ElfRelocOffset + objabi.RelocType(elf.R_ARM_GOTOFF): // R_ARM_GOTOFF32
+ su := ldr.MakeSymbolUpdater(s)
+ su.SetRelocType(rIdx, objabi.R_GOTOFF)
+ return true
+
+ case objabi.ElfRelocOffset + objabi.RelocType(elf.R_ARM_GOTPC): // R_ARM_BASE_PREL
+ su := ldr.MakeSymbolUpdater(s)
+ su.SetRelocType(rIdx, objabi.R_PCREL)
+ su.SetRelocSym(rIdx, syms.GOT)
+ su.SetRelocAdd(rIdx, r.Add()+4)
+ return true
+
+ case objabi.ElfRelocOffset + objabi.RelocType(elf.R_ARM_CALL):
+ su := ldr.MakeSymbolUpdater(s)
+ su.SetRelocType(rIdx, objabi.R_CALLARM)
+ if targType == sym.SDYNIMPORT {
+ addpltsym(target, ldr, syms, targ)
+ su.SetRelocSym(rIdx, syms.PLT)
+ su.SetRelocAdd(rIdx, int64(braddoff(int32(r.Add()), ldr.SymPlt(targ)/4)))
+ }
+ return true
+
+ case objabi.ElfRelocOffset + objabi.RelocType(elf.R_ARM_REL32): // R_ARM_REL32
+ su := ldr.MakeSymbolUpdater(s)
+ su.SetRelocType(rIdx, objabi.R_PCREL)
+ su.SetRelocAdd(rIdx, r.Add()+4)
+ return true
+
+ case objabi.ElfRelocOffset + objabi.RelocType(elf.R_ARM_ABS32):
+ if targType == sym.SDYNIMPORT {
+ ldr.Errorf(s, "unexpected R_ARM_ABS32 relocation for dynamic symbol %s", ldr.SymName(targ))
+ }
+ su := ldr.MakeSymbolUpdater(s)
+ su.SetRelocType(rIdx, objabi.R_ADDR)
+ return true
+
+ case objabi.ElfRelocOffset + objabi.RelocType(elf.R_ARM_PC24),
+ objabi.ElfRelocOffset + objabi.RelocType(elf.R_ARM_JUMP24):
+ su := ldr.MakeSymbolUpdater(s)
+ su.SetRelocType(rIdx, objabi.R_CALLARM)
+ if targType == sym.SDYNIMPORT {
+ addpltsym(target, ldr, syms, targ)
+ su.SetRelocSym(rIdx, syms.PLT)
+ su.SetRelocAdd(rIdx, int64(braddoff(int32(r.Add()), ldr.SymPlt(targ)/4)))
+ }
+
+ return true
+ }
+
+ // Handle references to ELF symbols from our own object files.
+ if targType != sym.SDYNIMPORT {
+ return true
+ }
+
+ // Reread the reloc to incorporate any changes in type above.
+ relocs := ldr.Relocs(s)
+ r = relocs.At(rIdx)
+
+ switch r.Type() {
+ case objabi.R_CALLARM:
+ if target.IsExternal() {
+ // External linker will do this relocation.
+ return true
+ }
+ addpltsym(target, ldr, syms, targ)
+ su := ldr.MakeSymbolUpdater(s)
+ su.SetRelocSym(rIdx, syms.PLT)
+ su.SetRelocAdd(rIdx, int64(braddoff(int32(r.Add()), ldr.SymPlt(targ)/4))) // TODO: don't use r.Add for instruction bytes (issue 19811)
+ return true
+
+ case objabi.R_ADDR:
+ if ldr.SymType(s) != sym.SDATA {
+ break
+ }
+ if target.IsElf() {
+ ld.Adddynsym(ldr, target, syms, targ)
+ rel := ldr.MakeSymbolUpdater(syms.Rel)
+ rel.AddAddrPlus(target.Arch, s, int64(r.Off()))
+ rel.AddUint32(target.Arch, elf.R_INFO32(uint32(ldr.SymDynid(targ)), uint32(elf.R_ARM_GLOB_DAT))) // we need a nil + A dynamic reloc
+ su := ldr.MakeSymbolUpdater(s)
+ su.SetRelocType(rIdx, objabi.R_CONST) // write r->add during relocsym
+ su.SetRelocSym(rIdx, 0)
+ return true
+ }
+ }
+
+ return false
+}
+
+func elfreloc1(ctxt *ld.Link, out *ld.OutBuf, ldr *loader.Loader, s loader.Sym, r loader.ExtReloc, ri int, sectoff int64) bool {
+ out.Write32(uint32(sectoff))
+
+ elfsym := ld.ElfSymForReloc(ctxt, r.Xsym)
+ siz := r.Size
+ switch r.Type {
+ default:
+ return false
+ case objabi.R_ADDR, objabi.R_DWARFSECREF:
+ if siz == 4 {
+ out.Write32(uint32(elf.R_ARM_ABS32) | uint32(elfsym)<<8)
+ } else {
+ return false
+ }
+ case objabi.R_PCREL:
+ if siz == 4 {
+ out.Write32(uint32(elf.R_ARM_REL32) | uint32(elfsym)<<8)
+ } else {
+ return false
+ }
+ case objabi.R_CALLARM:
+ if siz == 4 {
+ relocs := ldr.Relocs(s)
+ r := relocs.At(ri)
+ if r.Add()&0xff000000 == 0xeb000000 { // BL // TODO: using r.Add here is bad (issue 19811)
+ out.Write32(uint32(elf.R_ARM_CALL) | uint32(elfsym)<<8)
+ } else {
+ out.Write32(uint32(elf.R_ARM_JUMP24) | uint32(elfsym)<<8)
+ }
+ } else {
+ return false
+ }
+ case objabi.R_TLS_LE:
+ out.Write32(uint32(elf.R_ARM_TLS_LE32) | uint32(elfsym)<<8)
+ case objabi.R_TLS_IE:
+ out.Write32(uint32(elf.R_ARM_TLS_IE32) | uint32(elfsym)<<8)
+ case objabi.R_GOTPCREL:
+ if siz == 4 {
+ out.Write32(uint32(elf.R_ARM_GOT_PREL) | uint32(elfsym)<<8)
+ } else {
+ return false
+ }
+ }
+
+ return true
+}
+
+func elfsetupplt(ctxt *ld.Link, plt, got *loader.SymbolBuilder, dynamic loader.Sym) {
+ if plt.Size() == 0 {
+ // str lr, [sp, #-4]!
+ plt.AddUint32(ctxt.Arch, 0xe52de004)
+
+ // ldr lr, [pc, #4]
+ plt.AddUint32(ctxt.Arch, 0xe59fe004)
+
+ // add lr, pc, lr
+ plt.AddUint32(ctxt.Arch, 0xe08fe00e)
+
+ // ldr pc, [lr, #8]!
+ plt.AddUint32(ctxt.Arch, 0xe5bef008)
+
+ // .word &GLOBAL_OFFSET_TABLE[0] - .
+ plt.AddPCRelPlus(ctxt.Arch, got.Sym(), 4)
+
+ // the first .plt entry requires 3 .plt.got entries
+ got.AddUint32(ctxt.Arch, 0)
+
+ got.AddUint32(ctxt.Arch, 0)
+ got.AddUint32(ctxt.Arch, 0)
+ }
+}
+
+func machoreloc1(*sys.Arch, *ld.OutBuf, *loader.Loader, loader.Sym, loader.ExtReloc, int64) bool {
+ return false
+}
+
+func pereloc1(arch *sys.Arch, out *ld.OutBuf, ldr *loader.Loader, s loader.Sym, r loader.ExtReloc, sectoff int64) bool {
+ rs := r.Xsym
+ rt := r.Type
+
+ if ldr.SymDynid(rs) < 0 {
+ ldr.Errorf(s, "reloc %d (%s) to non-coff symbol %s type=%d (%s)", rt, sym.RelocName(arch, rt), ldr.SymName(rs), ldr.SymType(rs), ldr.SymType(rs))
+ return false
+ }
+
+ out.Write32(uint32(sectoff))
+ out.Write32(uint32(ldr.SymDynid(rs)))
+
+ var v uint32
+ switch rt {
+ default:
+ // unsupported relocation type
+ return false
+
+ case objabi.R_DWARFSECREF:
+ v = ld.IMAGE_REL_ARM_SECREL
+
+ case objabi.R_ADDR:
+ v = ld.IMAGE_REL_ARM_ADDR32
+ }
+
+ out.Write16(uint16(v))
+
+ return true
+}
+
+// sign extend a 24-bit integer
+func signext24(x int64) int32 {
+ return (int32(x) << 8) >> 8
+}
+
+// encode an immediate in ARM's imm12 format. copied from ../../../internal/obj/arm/asm5.go
+func immrot(v uint32) uint32 {
+ for i := 0; i < 16; i++ {
+ if v&^0xff == 0 {
+ return uint32(i<<8) | v | 1<<25
+ }
+ v = v<<2 | v>>30
+ }
+ return 0
+}
+
+// Convert the direct jump relocation r to refer to a trampoline if the target is too far
+func trampoline(ctxt *ld.Link, ldr *loader.Loader, ri int, rs, s loader.Sym) {
+ relocs := ldr.Relocs(s)
+ r := relocs.At(ri)
+ switch r.Type() {
+ case objabi.R_CALLARM:
+ var t int64
+ // ldr.SymValue(rs) == 0 indicates a cross-package jump to a function that is not yet
+ // laid out. Conservatively use a trampoline. This should be rare, as we lay out packages
+ // in dependency order.
+ if ldr.SymValue(rs) != 0 {
+ // r.Add is the instruction
+ // low 24-bit encodes the target address
+ t = (ldr.SymValue(rs) + int64(signext24(r.Add()&0xffffff)*4) - (ldr.SymValue(s) + int64(r.Off()))) / 4
+ }
+ if t > 0x7fffff || t < -0x800000 || ldr.SymValue(rs) == 0 || (*ld.FlagDebugTramp > 1 && ldr.SymPkg(s) != ldr.SymPkg(rs)) {
+ // direct call too far, need to insert trampoline.
+ // look up existing trampolines first. if we found one within the range
+ // of direct call, we can reuse it. otherwise create a new one.
+ offset := (signext24(r.Add()&0xffffff) + 2) * 4
+ var tramp loader.Sym
+ for i := 0; ; i++ {
+ oName := ldr.SymName(rs)
+ name := oName + fmt.Sprintf("%+d-tramp%d", offset, i)
+ tramp = ldr.LookupOrCreateSym(name, int(ldr.SymVersion(rs)))
+ ldr.SetAttrReachable(tramp, true)
+ if ldr.SymType(tramp) == sym.SDYNIMPORT {
+ // don't reuse trampoline defined in other module
+ continue
+ }
+ if oName == "runtime.deferreturn" {
+ ldr.SetIsDeferReturnTramp(tramp, true)
+ }
+ if ldr.SymValue(tramp) == 0 {
+ // either the trampoline does not exist -- we need to create one,
+ // or found one the address which is not assigned -- this will be
+ // laid down immediately after the current function. use this one.
+ break
+ }
+
+ t = (ldr.SymValue(tramp) - 8 - (ldr.SymValue(s) + int64(r.Off()))) / 4
+ if t >= -0x800000 && t < 0x7fffff {
+ // found an existing trampoline that is not too far
+ // we can just use it
+ break
+ }
+ }
+ if ldr.SymType(tramp) == 0 {
+ // trampoline does not exist, create one
+ trampb := ldr.MakeSymbolUpdater(tramp)
+ ctxt.AddTramp(trampb)
+ if ctxt.DynlinkingGo() {
+ if immrot(uint32(offset)) == 0 {
+ ctxt.Errorf(s, "odd offset in dynlink direct call: %v+%d", ldr.SymName(rs), offset)
+ }
+ gentrampdyn(ctxt.Arch, trampb, rs, int64(offset))
+ } else if ctxt.BuildMode == ld.BuildModeCArchive || ctxt.BuildMode == ld.BuildModeCShared || ctxt.BuildMode == ld.BuildModePIE {
+ gentramppic(ctxt.Arch, trampb, rs, int64(offset))
+ } else {
+ gentramp(ctxt.Arch, ctxt.LinkMode, ldr, trampb, rs, int64(offset))
+ }
+ }
+ // modify reloc to point to tramp, which will be resolved later
+ sb := ldr.MakeSymbolUpdater(s)
+ relocs := sb.Relocs()
+ r := relocs.At(ri)
+ r.SetSym(tramp)
+ r.SetAdd(r.Add()&0xff000000 | 0xfffffe) // clear the offset embedded in the instruction
+ }
+ default:
+ ctxt.Errorf(s, "trampoline called with non-jump reloc: %d (%s)", r.Type(), sym.RelocName(ctxt.Arch, r.Type()))
+ }
+}
+
+// generate a trampoline to target+offset
+func gentramp(arch *sys.Arch, linkmode ld.LinkMode, ldr *loader.Loader, tramp *loader.SymbolBuilder, target loader.Sym, offset int64) {
+ tramp.SetSize(12) // 3 instructions
+ P := make([]byte, tramp.Size())
+ t := ldr.SymValue(target) + offset
+ o1 := uint32(0xe5900000 | 11<<12 | 15<<16) // MOVW (R15), R11 // R15 is actual pc + 8
+ o2 := uint32(0xe12fff10 | 11) // JMP (R11)
+ o3 := uint32(t) // WORD $target
+ arch.ByteOrder.PutUint32(P, o1)
+ arch.ByteOrder.PutUint32(P[4:], o2)
+ arch.ByteOrder.PutUint32(P[8:], o3)
+ tramp.SetData(P)
+
+ if linkmode == ld.LinkExternal || ldr.SymValue(target) == 0 {
+ r, _ := tramp.AddRel(objabi.R_ADDR)
+ r.SetOff(8)
+ r.SetSiz(4)
+ r.SetSym(target)
+ r.SetAdd(offset)
+ }
+}
+
+// generate a trampoline to target+offset in position independent code
+func gentramppic(arch *sys.Arch, tramp *loader.SymbolBuilder, target loader.Sym, offset int64) {
+ tramp.SetSize(16) // 4 instructions
+ P := make([]byte, tramp.Size())
+ o1 := uint32(0xe5900000 | 11<<12 | 15<<16 | 4) // MOVW 4(R15), R11 // R15 is actual pc + 8
+ o2 := uint32(0xe0800000 | 11<<12 | 15<<16 | 11) // ADD R15, R11, R11
+ o3 := uint32(0xe12fff10 | 11) // JMP (R11)
+ o4 := uint32(0) // WORD $(target-pc) // filled in with relocation
+ arch.ByteOrder.PutUint32(P, o1)
+ arch.ByteOrder.PutUint32(P[4:], o2)
+ arch.ByteOrder.PutUint32(P[8:], o3)
+ arch.ByteOrder.PutUint32(P[12:], o4)
+ tramp.SetData(P)
+
+ r, _ := tramp.AddRel(objabi.R_PCREL)
+ r.SetOff(12)
+ r.SetSiz(4)
+ r.SetSym(target)
+ r.SetAdd(offset + 4)
+}
+
+// generate a trampoline to target+offset in dynlink mode (using GOT)
+func gentrampdyn(arch *sys.Arch, tramp *loader.SymbolBuilder, target loader.Sym, offset int64) {
+ tramp.SetSize(20) // 5 instructions
+ o1 := uint32(0xe5900000 | 11<<12 | 15<<16 | 8) // MOVW 8(R15), R11 // R15 is actual pc + 8
+ o2 := uint32(0xe0800000 | 11<<12 | 15<<16 | 11) // ADD R15, R11, R11
+ o3 := uint32(0xe5900000 | 11<<12 | 11<<16) // MOVW (R11), R11
+ o4 := uint32(0xe12fff10 | 11) // JMP (R11)
+ o5 := uint32(0) // WORD $target@GOT // filled in with relocation
+ o6 := uint32(0)
+ if offset != 0 {
+ // insert an instruction to add offset
+ tramp.SetSize(24) // 6 instructions
+ o6 = o5
+ o5 = o4
+ o4 = 0xe2800000 | 11<<12 | 11<<16 | immrot(uint32(offset)) // ADD $offset, R11, R11
+ o1 = uint32(0xe5900000 | 11<<12 | 15<<16 | 12) // MOVW 12(R15), R11
+ }
+ P := make([]byte, tramp.Size())
+ arch.ByteOrder.PutUint32(P, o1)
+ arch.ByteOrder.PutUint32(P[4:], o2)
+ arch.ByteOrder.PutUint32(P[8:], o3)
+ arch.ByteOrder.PutUint32(P[12:], o4)
+ arch.ByteOrder.PutUint32(P[16:], o5)
+ if offset != 0 {
+ arch.ByteOrder.PutUint32(P[20:], o6)
+ }
+ tramp.SetData(P)
+
+ r, _ := tramp.AddRel(objabi.R_GOTPCREL)
+ r.SetOff(16)
+ r.SetSiz(4)
+ r.SetSym(target)
+ r.SetAdd(8)
+ if offset != 0 {
+ // increase reloc offset by 4 as we inserted an ADD instruction
+ r.SetOff(20)
+ r.SetAdd(12)
+ }
+}
+
+func archreloc(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, r loader.Reloc, s loader.Sym, val int64) (o int64, nExtReloc int, ok bool) {
+ rs := r.Sym()
+ rs = ldr.ResolveABIAlias(rs)
+ if target.IsExternal() {
+ switch r.Type() {
+ case objabi.R_CALLARM:
+ // set up addend for eventual relocation via outer symbol.
+ _, off := ld.FoldSubSymbolOffset(ldr, rs)
+ xadd := int64(signext24(r.Add()&0xffffff))*4 + off
+ if xadd/4 > 0x7fffff || xadd/4 < -0x800000 {
+ ldr.Errorf(s, "direct call too far %d", xadd/4)
+ }
+ return int64(braddoff(int32(0xff000000&uint32(r.Add())), int32(0xffffff&uint32(xadd/4)))), 1, true
+ }
+ return -1, 0, false
+ }
+
+ const isOk = true
+ const noExtReloc = 0
+ switch r.Type() {
+ // The following three arch specific relocations are only for generation of
+ // Linux/ARM ELF's PLT entry (3 assembler instruction)
+ case objabi.R_PLT0: // add ip, pc, #0xXX00000
+ if ldr.SymValue(syms.GOTPLT) < ldr.SymValue(syms.PLT) {
+ ldr.Errorf(s, ".got.plt should be placed after .plt section.")
+ }
+ return 0xe28fc600 + (0xff & (int64(uint32(ldr.SymValue(rs)-(ldr.SymValue(syms.PLT)+int64(r.Off()))+r.Add())) >> 20)), noExtReloc, isOk
+ case objabi.R_PLT1: // add ip, ip, #0xYY000
+ return 0xe28cca00 + (0xff & (int64(uint32(ldr.SymValue(rs)-(ldr.SymValue(syms.PLT)+int64(r.Off()))+r.Add()+4)) >> 12)), noExtReloc, isOk
+ case objabi.R_PLT2: // ldr pc, [ip, #0xZZZ]!
+ return 0xe5bcf000 + (0xfff & int64(uint32(ldr.SymValue(rs)-(ldr.SymValue(syms.PLT)+int64(r.Off()))+r.Add()+8))), noExtReloc, isOk
+ case objabi.R_CALLARM: // bl XXXXXX or b YYYYYY
+ // r.Add is the instruction
+ // low 24-bit encodes the target address
+ t := (ldr.SymValue(rs) + int64(signext24(r.Add()&0xffffff)*4) - (ldr.SymValue(s) + int64(r.Off()))) / 4
+ if t > 0x7fffff || t < -0x800000 {
+ ldr.Errorf(s, "direct call too far: %s %x", ldr.SymName(rs), t)
+ }
+ return int64(braddoff(int32(0xff000000&uint32(r.Add())), int32(0xffffff&t))), noExtReloc, isOk
+ }
+
+ return val, 0, false
+}
+
+func archrelocvariant(*ld.Target, *loader.Loader, loader.Reloc, sym.RelocVariant, loader.Sym, int64) int64 {
+ log.Fatalf("unexpected relocation variant")
+ return -1
+}
+
+func extreloc(target *ld.Target, ldr *loader.Loader, r loader.Reloc, s loader.Sym) (loader.ExtReloc, bool) {
+ rs := ldr.ResolveABIAlias(r.Sym())
+ var rr loader.ExtReloc
+ switch r.Type() {
+ case objabi.R_CALLARM:
+ // set up addend for eventual relocation via outer symbol.
+ rs, off := ld.FoldSubSymbolOffset(ldr, rs)
+ rr.Xadd = int64(signext24(r.Add()&0xffffff))*4 + off
+ rst := ldr.SymType(rs)
+ if rst != sym.SHOSTOBJ && rst != sym.SDYNIMPORT && rst != sym.SUNDEFEXT && ldr.SymSect(rs) == nil {
+ ldr.Errorf(s, "missing section for %s", ldr.SymName(rs))
+ }
+ rr.Xsym = rs
+ rr.Type = r.Type()
+ rr.Size = r.Siz()
+ return rr, true
+ }
+ return rr, false
+}
+
+func addpltreloc(ldr *loader.Loader, plt *loader.SymbolBuilder, got *loader.SymbolBuilder, s loader.Sym, typ objabi.RelocType) {
+ r, _ := plt.AddRel(typ)
+ r.SetSym(got.Sym())
+ r.SetOff(int32(plt.Size()))
+ r.SetSiz(4)
+ r.SetAdd(int64(ldr.SymGot(s)) - 8)
+
+ plt.SetReachable(true)
+ plt.SetSize(plt.Size() + 4)
+ plt.Grow(plt.Size())
+}
+
+func addpltsym(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loader.Sym) {
+ if ldr.SymPlt(s) >= 0 {
+ return
+ }
+
+ ld.Adddynsym(ldr, target, syms, s)
+
+ if target.IsElf() {
+ plt := ldr.MakeSymbolUpdater(syms.PLT)
+ got := ldr.MakeSymbolUpdater(syms.GOTPLT)
+ rel := ldr.MakeSymbolUpdater(syms.RelPLT)
+ if plt.Size() == 0 {
+ panic("plt is not set up")
+ }
+
+ // .got entry
+ ldr.SetGot(s, int32(got.Size()))
+
+ // In theory, all GOT should point to the first PLT entry,
+ // Linux/ARM's dynamic linker will do that for us, but FreeBSD/ARM's
+ // dynamic linker won't, so we'd better do it ourselves.
+ got.AddAddrPlus(target.Arch, plt.Sym(), 0)
+
+ // .plt entry, this depends on the .got entry
+ ldr.SetPlt(s, int32(plt.Size()))
+
+ addpltreloc(ldr, plt, got, s, objabi.R_PLT0) // add lr, pc, #0xXX00000
+ addpltreloc(ldr, plt, got, s, objabi.R_PLT1) // add lr, lr, #0xYY000
+ addpltreloc(ldr, plt, got, s, objabi.R_PLT2) // ldr pc, [lr, #0xZZZ]!
+
+ // rel
+ rel.AddAddrPlus(target.Arch, got.Sym(), int64(ldr.SymGot(s)))
+
+ rel.AddUint32(target.Arch, elf.R_INFO32(uint32(ldr.SymDynid(s)), uint32(elf.R_ARM_JUMP_SLOT)))
+ } else {
+ ldr.Errorf(s, "addpltsym: unsupported binary format")
+ }
+}
+
+func addgotsyminternal(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loader.Sym) {
+ if ldr.SymGot(s) >= 0 {
+ return
+ }
+
+ got := ldr.MakeSymbolUpdater(syms.GOT)
+ ldr.SetGot(s, int32(got.Size()))
+ got.AddAddrPlus(target.Arch, s, 0)
+
+ if target.IsElf() {
+ } else {
+ ldr.Errorf(s, "addgotsyminternal: unsupported binary format")
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-15 10:09:54 +0000