Elfreloc1 func(*Link, *OutBuf, *loader.Loader, loader.Sym, loader.ExtReloc, int, int64) bool
ElfrelocSize uint32 // size of an ELF relocation record, must match Elfreloc1.
Elfsetupplt func(ctxt *Link, plt, gotplt *loader.SymbolBuilder, dynamic loader.Sym)
- Gentext func(*Link, *loader.Loader)
+ Gentext func(*Link, *loader.Loader) // Generate text before addressing has been performed.
Machoreloc1 func(*sys.Arch, *OutBuf, *loader.Loader, loader.Sym, loader.ExtReloc, int64) bool
MachorelocSize uint32 // size of an Mach-O relocation record, must match Machoreloc1.
PEreloc1 func(*sys.Arch, *OutBuf, *loader.Loader, loader.Sym, loader.ExtReloc, int64) bool
Xcoffreloc1 func(*sys.Arch, *OutBuf, *loader.Loader, loader.Sym, loader.ExtReloc, int64) bool
+ // Generate additional symbols for the native symbol table just prior to
+ // code generation.
+ GenSymsLate func(*Link, *loader.Loader)
+
// TLSIEtoLE converts a TLS Initial Executable relocation to
// a TLS Local Executable relocation.
//
"cmd/link/internal/ld"
"cmd/link/internal/loader"
"cmd/link/internal/sym"
+ "debug/elf"
"fmt"
"log"
+ "sort"
)
+// fakeLabelName matches the RISCV_FAKE_LABEL_NAME from binutils.
+const fakeLabelName = ".L0 "
+
func gentext(ctxt *ld.Link, ldr *loader.Loader) {
}
+func genSymsLate(ctxt *ld.Link, ldr *loader.Loader) {
+ if ctxt.LinkMode != ld.LinkExternal {
+ return
+ }
+
+ // Generate a local text symbol for each relocation target, as the
+ // R_RISCV_PCREL_LO12_* relocations generated by elfreloc1 need it.
+ if ctxt.Textp == nil {
+ log.Fatal("genSymsLate called before Textp has been assigned")
+ }
+ var hi20Syms []loader.Sym
+ for _, s := range ctxt.Textp {
+ relocs := ldr.Relocs(s)
+ for ri := 0; ri < relocs.Count(); ri++ {
+ r := relocs.At(ri)
+ if r.Type() != objabi.R_RISCV_PCREL_ITYPE && r.Type() != objabi.R_RISCV_PCREL_STYPE {
+ continue
+ }
+ if r.Off() == 0 && ldr.SymType(s) == sym.STEXT {
+ // Use the symbol for the function instead of creating
+ // an overlapping symbol.
+ continue
+ }
+
+ // TODO(jsing): Consider generating ELF symbols without needing
+ // loader symbols, in order to reduce memory consumption. This
+ // would require changes to genelfsym so that it called
+ // putelfsym and putelfsyment as appropriate.
+ sb := ldr.MakeSymbolBuilder(fakeLabelName)
+ sb.SetType(sym.STEXT)
+ sb.SetValue(ldr.SymValue(s) + int64(r.Off()))
+ sb.SetLocal(true)
+ sb.SetReachable(true)
+ sb.SetVisibilityHidden(true)
+ sb.SetSect(ldr.SymSect(s))
+ if outer := ldr.OuterSym(s); outer != 0 {
+ ldr.AddInteriorSym(outer, sb.Sym())
+ }
+ hi20Syms = append(hi20Syms, sb.Sym())
+ }
+ }
+ ctxt.Textp = append(ctxt.Textp, hi20Syms...)
+ ldr.SortSyms(ctxt.Textp)
+}
+
+func findHI20Symbol(ctxt *ld.Link, ldr *loader.Loader, val int64) loader.Sym {
+ idx := sort.Search(len(ctxt.Textp), func(i int) bool { return ldr.SymValue(ctxt.Textp[i]) >= val })
+ if idx >= len(ctxt.Textp) {
+ return 0
+ }
+ if s := ctxt.Textp[idx]; ldr.SymValue(s) == val && ldr.SymType(s) == sym.STEXT {
+ return s
+ }
+ return 0
+}
+
func elfreloc1(ctxt *ld.Link, out *ld.OutBuf, ldr *loader.Loader, s loader.Sym, r loader.ExtReloc, ri int, sectoff int64) bool {
- log.Fatalf("elfreloc1")
- return false
+ elfsym := ld.ElfSymForReloc(ctxt, r.Xsym)
+ switch r.Type {
+ case objabi.R_ADDR, objabi.R_DWARFSECREF:
+ out.Write64(uint64(sectoff))
+ switch r.Size {
+ case 4:
+ out.Write64(uint64(elf.R_RISCV_32) | uint64(elfsym)<<32)
+ case 8:
+ out.Write64(uint64(elf.R_RISCV_64) | uint64(elfsym)<<32)
+ default:
+ ld.Errorf(nil, "unknown size %d for %v relocation", r.Size, r.Type)
+ return false
+ }
+ out.Write64(uint64(r.Xadd))
+
+ case objabi.R_CALLRISCV:
+ // Call relocations are currently handled via R_RISCV_PCREL_ITYPE.
+ // TODO(jsing): Consider generating elf.R_RISCV_CALL instead of a
+ // HI20/LO12_I pair.
+
+ case objabi.R_RISCV_PCREL_ITYPE, objabi.R_RISCV_PCREL_STYPE:
+ // Find the text symbol for the AUIPC instruction targeted
+ // by this relocation.
+ relocs := ldr.Relocs(s)
+ offset := int64(relocs.At(ri).Off())
+ hi20Sym := findHI20Symbol(ctxt, ldr, ldr.SymValue(s)+offset)
+ if hi20Sym == 0 {
+ ld.Errorf(nil, "failed to find text symbol for HI20 relocation at %d (%x)", sectoff, ldr.SymValue(s)+offset)
+ return false
+ }
+ hi20ElfSym := ld.ElfSymForReloc(ctxt, hi20Sym)
+
+ // Emit two relocations - a R_RISCV_PCREL_HI20 relocation and a
+ // corresponding R_RISCV_PCREL_LO12_I or R_RISCV_PCREL_LO12_S relocation.
+ // Note that the LO12 relocation must point to a target that has a valid
+ // HI20 PC-relative relocation text symbol, which in turn points to the
+ // given symbol. For further details see the ELF specification for RISC-V:
+ //
+ // https://github.com/riscv/riscv-elf-psabi-doc/blob/master/riscv-elf.md#pc-relative-symbol-addresses
+ //
+ var hiRel, loRel elf.R_RISCV
+ switch r.Type {
+ case objabi.R_RISCV_PCREL_ITYPE:
+ hiRel, loRel = elf.R_RISCV_PCREL_HI20, elf.R_RISCV_PCREL_LO12_I
+ case objabi.R_RISCV_PCREL_STYPE:
+ hiRel, loRel = elf.R_RISCV_PCREL_HI20, elf.R_RISCV_PCREL_LO12_S
+ }
+ out.Write64(uint64(sectoff))
+ out.Write64(uint64(hiRel) | uint64(elfsym)<<32)
+ out.Write64(uint64(r.Xadd))
+ out.Write64(uint64(sectoff + 4))
+ out.Write64(uint64(loRel) | uint64(hi20ElfSym)<<32)
+ out.Write64(uint64(0))
+
+ default:
+ return false
+ }
+
+ return true
}
func elfsetupplt(ctxt *ld.Link, plt, gotplt *loader.SymbolBuilder, dynamic loader.Sym) {
- log.Fatalf("elfsetuplt")
+ log.Fatalf("elfsetupplt")
}
func machoreloc1(*sys.Arch, *ld.OutBuf, *loader.Loader, loader.Sym, loader.ExtReloc, int64) bool {
}
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_CALLRISCV:
+ return val, 0, true
+
+ case objabi.R_RISCV_PCREL_ITYPE, objabi.R_RISCV_PCREL_STYPE:
+ return val, 2, true
+ }
+
+ return val, 0, false
+ }
+
+ rs := ldr.ResolveABIAlias(r.Sym())
+
switch r.Type() {
case objabi.R_CALLRISCV:
// Nothing to do.
log.Fatalf("archrelocvariant")
return -1
}
+
+func extreloc(target *ld.Target, ldr *loader.Loader, r loader.Reloc, s loader.Sym) (loader.ExtReloc, bool) {
+ switch r.Type() {
+ case objabi.R_RISCV_PCREL_ITYPE, objabi.R_RISCV_PCREL_STYPE:
+ return ld.ExtrelocViaOuterSym(ldr, r, s), true
+ }
+ return loader.ExtReloc{}, false
+}