| // Inferno utils/5l/asm.c |
| // https://bitbucket.org/inferno-os/inferno-os/src/default/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/oldlink/internal/ld" |
| "cmd/oldlink/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) { |
| if !ctxt.DynlinkingGo() { |
| return |
| } |
| addmoduledata := ctxt.Syms.Lookup("runtime.addmoduledata", 0) |
| if addmoduledata.Type == sym.STEXT && ctxt.BuildMode != ld.BuildModePlugin { |
| // we're linking a module containing the runtime -> no need for |
| // an init function |
| return |
| } |
| addmoduledata.Attr |= sym.AttrReachable |
| initfunc := ctxt.Syms.Lookup("go.link.addmoduledata", 0) |
| initfunc.Type = sym.STEXT |
| initfunc.Attr |= sym.AttrLocal |
| initfunc.Attr |= sym.AttrReachable |
| o := func(op uint32) { |
| initfunc.AddUint32(ctxt.Arch, op) |
| } |
| o(0xe59f0004) |
| o(0xe08f0000) |
| |
| o(0xeafffffe) |
| rel := initfunc.AddRel() |
| rel.Off = 8 |
| rel.Siz = 4 |
| rel.Sym = ctxt.Syms.Lookup("runtime.addmoduledata", 0) |
| rel.Type = objabi.R_CALLARM |
| rel.Add = 0xeafffffe // vomit |
| |
| o(0x00000000) |
| rel = initfunc.AddRel() |
| rel.Off = 12 |
| rel.Siz = 4 |
| rel.Sym = ctxt.Moduledata |
| rel.Type = objabi.R_PCREL |
| rel.Add = 4 |
| |
| if ctxt.BuildMode == ld.BuildModePlugin { |
| ctxt.Textp = append(ctxt.Textp, addmoduledata) |
| } |
| ctxt.Textp = append(ctxt.Textp, initfunc) |
| initarray_entry := ctxt.Syms.Lookup("go.link.addmoduledatainit", 0) |
| initarray_entry.Attr |= sym.AttrReachable |
| initarray_entry.Attr |= sym.AttrLocal |
| initarray_entry.Type = sym.SINITARR |
| initarray_entry.AddAddr(ctxt.Arch, initfunc) |
| } |
| |
| // 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(ctxt *ld.Link, s *sym.Symbol, r *sym.Reloc) bool { |
| targ := r.Sym |
| |
| switch r.Type { |
| default: |
| if r.Type >= objabi.ElfRelocOffset { |
| ld.Errorf(s, "unexpected relocation type %d (%s)", r.Type, sym.RelocName(ctxt.Arch, r.Type)) |
| return false |
| } |
| |
| // Handle relocations found in ELF object files. |
| case objabi.ElfRelocOffset + objabi.RelocType(elf.R_ARM_PLT32): |
| r.Type = objabi.R_CALLARM |
| |
| if targ.Type == sym.SDYNIMPORT { |
| addpltsym(ctxt, targ) |
| r.Sym = ctxt.Syms.Lookup(".plt", 0) |
| r.Add = int64(braddoff(int32(r.Add), targ.Plt()/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 targ.Type != sym.SDYNIMPORT { |
| addgotsyminternal(ctxt, targ) |
| } else { |
| addgotsym(ctxt, targ) |
| } |
| |
| r.Type = objabi.R_CONST // write r->add during relocsym |
| r.Sym = nil |
| r.Add += int64(targ.Got()) |
| return true |
| |
| case objabi.ElfRelocOffset + objabi.RelocType(elf.R_ARM_GOT_PREL): // GOT(nil) + A - nil |
| if targ.Type != sym.SDYNIMPORT { |
| addgotsyminternal(ctxt, targ) |
| } else { |
| addgotsym(ctxt, targ) |
| } |
| |
| r.Type = objabi.R_PCREL |
| r.Sym = ctxt.Syms.Lookup(".got", 0) |
| r.Add += int64(targ.Got()) + 4 |
| return true |
| |
| case objabi.ElfRelocOffset + objabi.RelocType(elf.R_ARM_GOTOFF): // R_ARM_GOTOFF32 |
| r.Type = objabi.R_GOTOFF |
| |
| return true |
| |
| case objabi.ElfRelocOffset + objabi.RelocType(elf.R_ARM_GOTPC): // R_ARM_BASE_PREL |
| r.Type = objabi.R_PCREL |
| |
| r.Sym = ctxt.Syms.Lookup(".got", 0) |
| r.Add += 4 |
| return true |
| |
| case objabi.ElfRelocOffset + objabi.RelocType(elf.R_ARM_CALL): |
| r.Type = objabi.R_CALLARM |
| if targ.Type == sym.SDYNIMPORT { |
| addpltsym(ctxt, targ) |
| r.Sym = ctxt.Syms.Lookup(".plt", 0) |
| r.Add = int64(braddoff(int32(r.Add), targ.Plt()/4)) |
| } |
| |
| return true |
| |
| case objabi.ElfRelocOffset + objabi.RelocType(elf.R_ARM_REL32): // R_ARM_REL32 |
| r.Type = objabi.R_PCREL |
| |
| r.Add += 4 |
| return true |
| |
| case objabi.ElfRelocOffset + objabi.RelocType(elf.R_ARM_ABS32): |
| if targ.Type == sym.SDYNIMPORT { |
| ld.Errorf(s, "unexpected R_ARM_ABS32 relocation for dynamic symbol %s", targ.Name) |
| } |
| r.Type = objabi.R_ADDR |
| return true |
| |
| // we can just ignore this, because we are targeting ARM V5+ anyway |
| case objabi.ElfRelocOffset + objabi.RelocType(elf.R_ARM_V4BX): |
| if r.Sym != nil { |
| // R_ARM_V4BX is ABS relocation, so this symbol is a dummy symbol, ignore it |
| r.Sym.Type = 0 |
| } |
| |
| r.Sym = nil |
| return true |
| |
| case objabi.ElfRelocOffset + objabi.RelocType(elf.R_ARM_PC24), |
| objabi.ElfRelocOffset + objabi.RelocType(elf.R_ARM_JUMP24): |
| r.Type = objabi.R_CALLARM |
| if targ.Type == sym.SDYNIMPORT { |
| addpltsym(ctxt, targ) |
| r.Sym = ctxt.Syms.Lookup(".plt", 0) |
| r.Add = int64(braddoff(int32(r.Add), targ.Plt()/4)) |
| } |
| |
| return true |
| } |
| |
| // Handle references to ELF symbols from our own object files. |
| if targ.Type != sym.SDYNIMPORT { |
| return true |
| } |
| |
| switch r.Type { |
| case objabi.R_CALLARM: |
| if ctxt.LinkMode == ld.LinkExternal { |
| // External linker will do this relocation. |
| return true |
| } |
| addpltsym(ctxt, targ) |
| r.Sym = ctxt.Syms.Lookup(".plt", 0) |
| r.Add = int64(targ.Plt()) |
| return true |
| |
| case objabi.R_ADDR: |
| if s.Type != sym.SDATA { |
| break |
| } |
| if ctxt.IsELF { |
| ld.Adddynsym(ctxt, targ) |
| rel := ctxt.Syms.Lookup(".rel", 0) |
| rel.AddAddrPlus(ctxt.Arch, s, int64(r.Off)) |
| rel.AddUint32(ctxt.Arch, ld.ELF32_R_INFO(uint32(targ.Dynid), uint32(elf.R_ARM_GLOB_DAT))) // we need a nil + A dynamic reloc |
| r.Type = objabi.R_CONST // write r->add during relocsym |
| r.Sym = nil |
| return true |
| } |
| } |
| |
| return false |
| } |
| |
| func elfreloc1(ctxt *ld.Link, r *sym.Reloc, sectoff int64) bool { |
| ctxt.Out.Write32(uint32(sectoff)) |
| |
| elfsym := r.Xsym.ElfsymForReloc() |
| switch r.Type { |
| default: |
| return false |
| case objabi.R_ADDR: |
| if r.Siz == 4 { |
| ctxt.Out.Write32(uint32(elf.R_ARM_ABS32) | uint32(elfsym)<<8) |
| } else { |
| return false |
| } |
| case objabi.R_PCREL: |
| if r.Siz == 4 { |
| ctxt.Out.Write32(uint32(elf.R_ARM_REL32) | uint32(elfsym)<<8) |
| } else { |
| return false |
| } |
| case objabi.R_CALLARM: |
| if r.Siz == 4 { |
| if r.Add&0xff000000 == 0xeb000000 { // BL |
| ctxt.Out.Write32(uint32(elf.R_ARM_CALL) | uint32(elfsym)<<8) |
| } else { |
| ctxt.Out.Write32(uint32(elf.R_ARM_JUMP24) | uint32(elfsym)<<8) |
| } |
| } else { |
| return false |
| } |
| case objabi.R_TLS_LE: |
| ctxt.Out.Write32(uint32(elf.R_ARM_TLS_LE32) | uint32(elfsym)<<8) |
| case objabi.R_TLS_IE: |
| ctxt.Out.Write32(uint32(elf.R_ARM_TLS_IE32) | uint32(elfsym)<<8) |
| case objabi.R_GOTPCREL: |
| if r.Siz == 4 { |
| ctxt.Out.Write32(uint32(elf.R_ARM_GOT_PREL) | uint32(elfsym)<<8) |
| } else { |
| return false |
| } |
| } |
| |
| return true |
| } |
| |
| func elfsetupplt(ctxt *ld.Link) { |
| plt := ctxt.Syms.Lookup(".plt", 0) |
| got := ctxt.Syms.Lookup(".got.plt", 0) |
| 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, 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(arch *sys.Arch, out *ld.OutBuf, s *sym.Symbol, r *sym.Reloc, sectoff int64) bool { |
| return false |
| } |
| |
| func pereloc1(arch *sys.Arch, out *ld.OutBuf, s *sym.Symbol, r *sym.Reloc, sectoff int64) bool { |
| rs := r.Xsym |
| |
| if rs.Dynid < 0 { |
| ld.Errorf(s, "reloc %d (%s) to non-coff symbol %s type=%d (%s)", r.Type, sym.RelocName(arch, r.Type), rs.Name, rs.Type, rs.Type) |
| return false |
| } |
| |
| out.Write32(uint32(sectoff)) |
| out.Write32(uint32(rs.Dynid)) |
| |
| var v uint32 |
| switch r.Type { |
| 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, r *sym.Reloc, s *sym.Symbol) { |
| switch r.Type { |
| case objabi.R_CALLARM: |
| // r.Add is the instruction |
| // low 24-bit encodes the target address |
| t := (ld.Symaddr(r.Sym) + int64(signext24(r.Add&0xffffff)*4) - (s.Value + int64(r.Off))) / 4 |
| if t > 0x7fffff || t < -0x800000 || (*ld.FlagDebugTramp > 1 && s.File != r.Sym.File) { |
| // 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 *sym.Symbol |
| for i := 0; ; i++ { |
| name := r.Sym.Name + fmt.Sprintf("%+d-tramp%d", offset, i) |
| tramp = ctxt.Syms.Lookup(name, int(r.Sym.Version)) |
| if tramp.Type == sym.SDYNIMPORT { |
| // don't reuse trampoline defined in other module |
| continue |
| } |
| if tramp.Value == 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 = (ld.Symaddr(tramp) - 8 - (s.Value + 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 tramp.Type == 0 { |
| // trampoline does not exist, create one |
| ctxt.AddTramp(tramp) |
| if ctxt.DynlinkingGo() { |
| if immrot(uint32(offset)) == 0 { |
| ld.Errorf(s, "odd offset in dynlink direct call: %v+%d", r.Sym, offset) |
| } |
| gentrampdyn(ctxt.Arch, tramp, r.Sym, int64(offset)) |
| } else if ctxt.BuildMode == ld.BuildModeCArchive || ctxt.BuildMode == ld.BuildModeCShared || ctxt.BuildMode == ld.BuildModePIE { |
| gentramppic(ctxt.Arch, tramp, r.Sym, int64(offset)) |
| } else { |
| gentramp(ctxt.Arch, ctxt.LinkMode, tramp, r.Sym, int64(offset)) |
| } |
| } |
| // modify reloc to point to tramp, which will be resolved later |
| r.Sym = tramp |
| r.Add = r.Add&0xff000000 | 0xfffffe // clear the offset embedded in the instruction |
| r.Done = false |
| } |
| default: |
| ld.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, tramp, target *sym.Symbol, offset int64) { |
| tramp.Size = 12 // 3 instructions |
| tramp.P = make([]byte, tramp.Size) |
| t := ld.Symaddr(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(tramp.P, o1) |
| arch.ByteOrder.PutUint32(tramp.P[4:], o2) |
| arch.ByteOrder.PutUint32(tramp.P[8:], o3) |
| |
| if linkmode == ld.LinkExternal { |
| r := tramp.AddRel() |
| r.Off = 8 |
| r.Type = objabi.R_ADDR |
| r.Siz = 4 |
| r.Sym = target |
| r.Add = offset |
| } |
| } |
| |
| // generate a trampoline to target+offset in position independent code |
| func gentramppic(arch *sys.Arch, tramp, target *sym.Symbol, offset int64) { |
| tramp.Size = 16 // 4 instructions |
| tramp.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(tramp.P, o1) |
| arch.ByteOrder.PutUint32(tramp.P[4:], o2) |
| arch.ByteOrder.PutUint32(tramp.P[8:], o3) |
| arch.ByteOrder.PutUint32(tramp.P[12:], o4) |
| |
| r := tramp.AddRel() |
| r.Off = 12 |
| r.Type = objabi.R_PCREL |
| r.Siz = 4 |
| r.Sym = target |
| r.Add = offset + 4 |
| } |
| |
| // generate a trampoline to target+offset in dynlink mode (using GOT) |
| func gentrampdyn(arch *sys.Arch, tramp, target *sym.Symbol, offset int64) { |
| tramp.Size = 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.Size = 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 |
| } |
| tramp.P = make([]byte, tramp.Size) |
| arch.ByteOrder.PutUint32(tramp.P, o1) |
| arch.ByteOrder.PutUint32(tramp.P[4:], o2) |
| arch.ByteOrder.PutUint32(tramp.P[8:], o3) |
| arch.ByteOrder.PutUint32(tramp.P[12:], o4) |
| arch.ByteOrder.PutUint32(tramp.P[16:], o5) |
| if offset != 0 { |
| arch.ByteOrder.PutUint32(tramp.P[20:], o6) |
| } |
| |
| r := tramp.AddRel() |
| r.Off = 16 |
| r.Type = objabi.R_GOTPCREL |
| r.Siz = 4 |
| r.Sym = target |
| r.Add = 8 |
| if offset != 0 { |
| // increase reloc offset by 4 as we inserted an ADD instruction |
| r.Off = 20 |
| r.Add = 12 |
| } |
| } |
| |
| func archreloc(ctxt *ld.Link, r *sym.Reloc, s *sym.Symbol, val int64) (int64, bool) { |
| if ctxt.LinkMode == ld.LinkExternal { |
| switch r.Type { |
| case objabi.R_CALLARM: |
| r.Done = false |
| |
| // set up addend for eventual relocation via outer symbol. |
| rs := r.Sym |
| |
| r.Xadd = int64(signext24(r.Add & 0xffffff)) |
| r.Xadd *= 4 |
| for rs.Outer != nil { |
| r.Xadd += ld.Symaddr(rs) - ld.Symaddr(rs.Outer) |
| rs = rs.Outer |
| } |
| |
| if rs.Type != sym.SHOSTOBJ && rs.Type != sym.SDYNIMPORT && rs.Type != sym.SUNDEFEXT && rs.Sect == nil { |
| ld.Errorf(s, "missing section for %s", rs.Name) |
| } |
| r.Xsym = rs |
| |
| if r.Xadd/4 > 0x7fffff || r.Xadd/4 < -0x800000 { |
| ld.Errorf(s, "direct call too far %d", r.Xadd/4) |
| } |
| |
| return int64(braddoff(int32(0xff000000&uint32(r.Add)), int32(0xffffff&uint32(r.Xadd/4)))), true |
| } |
| |
| return -1, false |
| } |
| |
| switch r.Type { |
| case objabi.R_CONST: |
| return r.Add, true |
| case objabi.R_GOTOFF: |
| return ld.Symaddr(r.Sym) + r.Add - ld.Symaddr(ctxt.Syms.Lookup(".got", 0)), true |
| |
| // 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 ld.Symaddr(ctxt.Syms.Lookup(".got.plt", 0)) < ld.Symaddr(ctxt.Syms.Lookup(".plt", 0)) { |
| ld.Errorf(s, ".got.plt should be placed after .plt section.") |
| } |
| return 0xe28fc600 + (0xff & (int64(uint32(ld.Symaddr(r.Sym)-(ld.Symaddr(ctxt.Syms.Lookup(".plt", 0))+int64(r.Off))+r.Add)) >> 20)), true |
| case objabi.R_PLT1: // add ip, ip, #0xYY000 |
| return 0xe28cca00 + (0xff & (int64(uint32(ld.Symaddr(r.Sym)-(ld.Symaddr(ctxt.Syms.Lookup(".plt", 0))+int64(r.Off))+r.Add+4)) >> 12)), true |
| case objabi.R_PLT2: // ldr pc, [ip, #0xZZZ]! |
| return 0xe5bcf000 + (0xfff & int64(uint32(ld.Symaddr(r.Sym)-(ld.Symaddr(ctxt.Syms.Lookup(".plt", 0))+int64(r.Off))+r.Add+8))), true |
| case objabi.R_CALLARM: // bl XXXXXX or b YYYYYY |
| // r.Add is the instruction |
| // low 24-bit encodes the target address |
| t := (ld.Symaddr(r.Sym) + int64(signext24(r.Add&0xffffff)*4) - (s.Value + int64(r.Off))) / 4 |
| if t > 0x7fffff || t < -0x800000 { |
| ld.Errorf(s, "direct call too far: %s %x", r.Sym.Name, t) |
| } |
| return int64(braddoff(int32(0xff000000&uint32(r.Add)), int32(0xffffff&t))), true |
| } |
| |
| return val, false |
| } |
| |
| func archrelocvariant(ctxt *ld.Link, r *sym.Reloc, s *sym.Symbol, t int64) int64 { |
| log.Fatalf("unexpected relocation variant") |
| return t |
| } |
| |
| func addpltreloc(ctxt *ld.Link, plt *sym.Symbol, got *sym.Symbol, s *sym.Symbol, typ objabi.RelocType) { |
| r := plt.AddRel() |
| r.Sym = got |
| r.Off = int32(plt.Size) |
| r.Siz = 4 |
| r.Type = typ |
| r.Add = int64(s.Got()) - 8 |
| |
| plt.Attr |= sym.AttrReachable |
| plt.Size += 4 |
| plt.Grow(plt.Size) |
| } |
| |
| func addpltsym(ctxt *ld.Link, s *sym.Symbol) { |
| if s.Plt() >= 0 { |
| return |
| } |
| |
| ld.Adddynsym(ctxt, s) |
| |
| if ctxt.IsELF { |
| plt := ctxt.Syms.Lookup(".plt", 0) |
| got := ctxt.Syms.Lookup(".got.plt", 0) |
| rel := ctxt.Syms.Lookup(".rel.plt", 0) |
| if plt.Size == 0 { |
| elfsetupplt(ctxt) |
| } |
| |
| // .got entry |
| s.SetGot(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(ctxt.Arch, plt, 0) |
| |
| // .plt entry, this depends on the .got entry |
| s.SetPlt(int32(plt.Size)) |
| |
| addpltreloc(ctxt, plt, got, s, objabi.R_PLT0) // add lr, pc, #0xXX00000 |
| addpltreloc(ctxt, plt, got, s, objabi.R_PLT1) // add lr, lr, #0xYY000 |
| addpltreloc(ctxt, plt, got, s, objabi.R_PLT2) // ldr pc, [lr, #0xZZZ]! |
| |
| // rel |
| rel.AddAddrPlus(ctxt.Arch, got, int64(s.Got())) |
| |
| rel.AddUint32(ctxt.Arch, ld.ELF32_R_INFO(uint32(s.Dynid), uint32(elf.R_ARM_JUMP_SLOT))) |
| } else { |
| ld.Errorf(s, "addpltsym: unsupported binary format") |
| } |
| } |
| |
| func addgotsyminternal(ctxt *ld.Link, s *sym.Symbol) { |
| if s.Got() >= 0 { |
| return |
| } |
| |
| got := ctxt.Syms.Lookup(".got", 0) |
| s.SetGot(int32(got.Size)) |
| |
| got.AddAddrPlus(ctxt.Arch, s, 0) |
| |
| if ctxt.IsELF { |
| } else { |
| ld.Errorf(s, "addgotsyminternal: unsupported binary format") |
| } |
| } |
| |
| func addgotsym(ctxt *ld.Link, s *sym.Symbol) { |
| if s.Got() >= 0 { |
| return |
| } |
| |
| ld.Adddynsym(ctxt, s) |
| got := ctxt.Syms.Lookup(".got", 0) |
| s.SetGot(int32(got.Size)) |
| got.AddUint32(ctxt.Arch, 0) |
| |
| if ctxt.IsELF { |
| rel := ctxt.Syms.Lookup(".rel", 0) |
| rel.AddAddrPlus(ctxt.Arch, got, int64(s.Got())) |
| rel.AddUint32(ctxt.Arch, ld.ELF32_R_INFO(uint32(s.Dynid), uint32(elf.R_ARM_GLOB_DAT))) |
| } else { |
| ld.Errorf(s, "addgotsym: unsupported binary format") |
| } |
| } |
| |
| func asmb(ctxt *ld.Link) { |
| if ctxt.IsELF { |
| ld.Asmbelfsetup() |
| } |
| |
| sect := ld.Segtext.Sections[0] |
| ctxt.Out.SeekSet(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff)) |
| ld.Codeblk(ctxt, int64(sect.Vaddr), int64(sect.Length)) |
| for _, sect = range ld.Segtext.Sections[1:] { |
| ctxt.Out.SeekSet(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff)) |
| ld.Datblk(ctxt, int64(sect.Vaddr), int64(sect.Length)) |
| } |
| |
| if ld.Segrodata.Filelen > 0 { |
| ctxt.Out.SeekSet(int64(ld.Segrodata.Fileoff)) |
| ld.Datblk(ctxt, int64(ld.Segrodata.Vaddr), int64(ld.Segrodata.Filelen)) |
| } |
| if ld.Segrelrodata.Filelen > 0 { |
| ctxt.Out.SeekSet(int64(ld.Segrelrodata.Fileoff)) |
| ld.Datblk(ctxt, int64(ld.Segrelrodata.Vaddr), int64(ld.Segrelrodata.Filelen)) |
| } |
| |
| ctxt.Out.SeekSet(int64(ld.Segdata.Fileoff)) |
| ld.Datblk(ctxt, int64(ld.Segdata.Vaddr), int64(ld.Segdata.Filelen)) |
| |
| ctxt.Out.SeekSet(int64(ld.Segdwarf.Fileoff)) |
| ld.Dwarfblk(ctxt, int64(ld.Segdwarf.Vaddr), int64(ld.Segdwarf.Filelen)) |
| } |
| |
| func asmb2(ctxt *ld.Link) { |
| /* output symbol table */ |
| ld.Symsize = 0 |
| |
| ld.Lcsize = 0 |
| symo := uint32(0) |
| if !*ld.FlagS { |
| // TODO: rationalize |
| switch ctxt.HeadType { |
| default: |
| if ctxt.IsELF { |
| symo = uint32(ld.Segdwarf.Fileoff + ld.Segdwarf.Filelen) |
| symo = uint32(ld.Rnd(int64(symo), int64(*ld.FlagRound))) |
| } |
| |
| case objabi.Hplan9: |
| symo = uint32(ld.Segdata.Fileoff + ld.Segdata.Filelen) |
| |
| case objabi.Hwindows: |
| symo = uint32(ld.Segdwarf.Fileoff + ld.Segdwarf.Filelen) |
| symo = uint32(ld.Rnd(int64(symo), ld.PEFILEALIGN)) |
| } |
| |
| ctxt.Out.SeekSet(int64(symo)) |
| switch ctxt.HeadType { |
| default: |
| if ctxt.IsELF { |
| ld.Asmelfsym(ctxt) |
| ctxt.Out.Flush() |
| ctxt.Out.Write(ld.Elfstrdat) |
| |
| if ctxt.LinkMode == ld.LinkExternal { |
| ld.Elfemitreloc(ctxt) |
| } |
| } |
| |
| case objabi.Hplan9: |
| ld.Asmplan9sym(ctxt) |
| ctxt.Out.Flush() |
| |
| sym := ctxt.Syms.Lookup("pclntab", 0) |
| if sym != nil { |
| ld.Lcsize = int32(len(sym.P)) |
| ctxt.Out.Write(sym.P) |
| ctxt.Out.Flush() |
| } |
| |
| case objabi.Hwindows: |
| // Do nothing |
| } |
| } |
| |
| ctxt.Out.SeekSet(0) |
| switch ctxt.HeadType { |
| default: |
| case objabi.Hplan9: /* plan 9 */ |
| ctxt.Out.Write32b(0x647) /* magic */ |
| ctxt.Out.Write32b(uint32(ld.Segtext.Filelen)) /* sizes */ |
| ctxt.Out.Write32b(uint32(ld.Segdata.Filelen)) |
| ctxt.Out.Write32b(uint32(ld.Segdata.Length - ld.Segdata.Filelen)) |
| ctxt.Out.Write32b(uint32(ld.Symsize)) /* nsyms */ |
| ctxt.Out.Write32b(uint32(ld.Entryvalue(ctxt))) /* va of entry */ |
| ctxt.Out.Write32b(0) |
| ctxt.Out.Write32b(uint32(ld.Lcsize)) |
| |
| case objabi.Hlinux, |
| objabi.Hfreebsd, |
| objabi.Hnetbsd, |
| objabi.Hopenbsd: |
| ld.Asmbelf(ctxt, int64(symo)) |
| |
| case objabi.Hwindows: |
| ld.Asmbpe(ctxt) |
| } |
| |
| ctxt.Out.Flush() |
| if *ld.FlagC { |
| fmt.Printf("textsize=%d\n", ld.Segtext.Filelen) |
| fmt.Printf("datsize=%d\n", ld.Segdata.Filelen) |
| fmt.Printf("bsssize=%d\n", ld.Segdata.Length-ld.Segdata.Filelen) |
| fmt.Printf("symsize=%d\n", ld.Symsize) |
| fmt.Printf("lcsize=%d\n", ld.Lcsize) |
| fmt.Printf("total=%d\n", ld.Segtext.Filelen+ld.Segdata.Length+uint64(ld.Symsize)+uint64(ld.Lcsize)) |
| } |
| } |
