return true
}
-// sign-extends from 24-bit.
-func signext24(x int64) int64 { return x << 40 >> 40 }
+// sign-extends from 21, 24-bit.
+func signext21(x int64) int64 { return x << (64 - 21) >> (64 - 21) }
+func signext24(x int64) int64 { return x << (64 - 24) >> (64 - 24) }
func machoreloc1(arch *sys.Arch, out *ld.OutBuf, ldr *loader.Loader, s loader.Sym, r loader.ExtReloc, sectoff int64) bool {
var v uint32
if xadd != signext24(xadd) {
// If the relocation target would overflow the addend, then target
// a linker-manufactured label symbol with a smaller addend instead.
- label := ldr.Lookup(machoLabelName(ldr, rs, xadd), ldr.SymVersion(rs))
+ label := ldr.Lookup(offsetLabelName(ldr, rs, xadd/machoRelocLimit*machoRelocLimit), ldr.SymVersion(rs))
if label != 0 {
xadd = ldr.SymValue(rs) + xadd - ldr.SymValue(label)
rs = label
}
func pereloc1(arch *sys.Arch, out *ld.OutBuf, ldr *loader.Loader, s loader.Sym, r loader.ExtReloc, sectoff int64) bool {
- var v uint32
-
rs := r.Xsym
rt := r.Type
- if ldr.SymDynid(rs) < 0 {
+ if r.Xadd != signext21(r.Xadd) {
+ // If the relocation target would overflow the addend, then target
+ // a linker-manufactured label symbol with a smaller addend instead.
+ label := ldr.Lookup(offsetLabelName(ldr, rs, r.Xadd/peRelocLimit*peRelocLimit), ldr.SymVersion(rs))
+ if label == 0 {
+ ldr.Errorf(s, "invalid relocation: %v %s+0x%x", rt, ldr.SymName(rs), r.Xadd)
+ return false
+ }
+ rs = label
+ }
+ if rt == objabi.R_CALLARM64 && r.Xadd != 0 {
+ label := ldr.Lookup(offsetLabelName(ldr, rs, r.Xadd), ldr.SymVersion(rs))
+ if label == 0 {
+ ldr.Errorf(s, "invalid relocation: %v %s+0x%x", rt, ldr.SymName(rs), r.Xadd)
+ return false
+ }
+ rs = label
+ }
+ symdynid := ldr.SymDynid(rs)
+ if symdynid < 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)))
-
switch rt {
default:
return false
case objabi.R_DWARFSECREF:
- v = ld.IMAGE_REL_ARM64_SECREL
+ out.Write32(uint32(sectoff))
+ out.Write32(uint32(symdynid))
+ out.Write16(ld.IMAGE_REL_ARM64_SECREL)
case objabi.R_ADDR:
+ out.Write32(uint32(sectoff))
+ out.Write32(uint32(symdynid))
if r.Size == 8 {
- v = ld.IMAGE_REL_ARM64_ADDR64
+ out.Write16(ld.IMAGE_REL_ARM64_ADDR64)
} else {
- v = ld.IMAGE_REL_ARM64_ADDR32
+ out.Write16(ld.IMAGE_REL_ARM64_ADDR32)
}
- }
- out.Write16(uint16(v))
+ case objabi.R_ADDRARM64:
+ // Note: r.Xadd has been taken care of below, in archreloc.
+ out.Write32(uint32(sectoff))
+ out.Write32(uint32(symdynid))
+ out.Write16(ld.IMAGE_REL_ARM64_PAGEBASE_REL21)
+
+ out.Write32(uint32(sectoff + 4))
+ out.Write32(uint32(symdynid))
+ out.Write16(ld.IMAGE_REL_ARM64_PAGEOFFSET_12A)
+
+ case objabi.R_CALLARM64:
+ // Note: r.Xadd has been taken care of above, by using a label pointing into the middle of the function.
+ out.Write32(uint32(sectoff))
+ out.Write32(uint32(symdynid))
+ out.Write16(ld.IMAGE_REL_ARM64_BRANCH26)
+ }
return true
}
nExtReloc = 4 // need another two relocations for non-zero addend
}
- // Note: ld64 currently has a bug that any non-zero addend for BR26 relocation
- // will make the linking fail because it thinks the code is not PIC even though
- // the BR26 relocation should be fully resolved at link time.
- // That is the reason why the next if block is disabled. When the bug in ld64
- // is fixed, we can enable this block and also enable duff's device in cmd/7g.
- if false && target.IsDarwin() {
+ if target.IsWindows() {
var o0, o1 uint32
-
if target.IsBigEndian() {
o0 = uint32(val >> 32)
o1 = uint32(val)
o0 = uint32(val)
o1 = uint32(val >> 32)
}
- // Mach-O wants the addend to be encoded in the instruction
- // Note that although Mach-O supports ARM64_RELOC_ADDEND, it
- // can only encode 24-bit of signed addend, but the instructions
- // supports 33-bit of signed addend, so we always encode the
- // addend in place.
- o0 |= (uint32((xadd>>12)&3) << 29) | (uint32((xadd>>12>>2)&0x7ffff) << 5)
- o1 |= uint32(xadd&0xfff) << 10
-
- // when laid out, the instruction order must always be o1, o2.
+
+ // The first instruction (ADRP) has a 21-bit immediate field,
+ // and the second (ADD) has a 12-bit immediate field.
+ // The first instruction is only for high bits, but to get the carry bits right we have
+ // to put the full addend, including the bottom 12 bits again.
+ // That limits the distance of any addend to only 21 bits.
+ // But we assume that LDRP's top bit will be interpreted as a sign bit,
+ // so we only use 20 bits.
+ // pereloc takes care of introducing new symbol labels
+ // every megabyte for longer relocations.
+ xadd := uint32(xadd)
+ o0 |= (xadd&3)<<29 | (xadd&0xffffc)<<3
+ o1 |= (xadd & 0xfff) << 10
+
if target.IsBigEndian() {
val = int64(o0)<<32 | int64(o1)
} else {
nExtReloc = 2 // need two ELF relocations. see elfreloc1
}
return val, nExtReloc, isOk
+
+ case objabi.R_ADDR:
+ if target.IsWindows() && r.Add() != 0 {
+ if r.Siz() == 8 {
+ val = r.Add()
+ } else if target.IsBigEndian() {
+ val = int64(uint32(val)) | int64(r.Add())<<32
+ } else {
+ val = val>>32<<32 | int64(uint32(r.Add()))
+ }
+ return val, 1, true
+ }
}
}
}
}
-const machoRelocLimit = 1 << 23
+const (
+ machoRelocLimit = 1 << 23
+ peRelocLimit = 1 << 20
+)
func gensymlate(ctxt *ld.Link, ldr *loader.Loader) {
// When external linking on darwin, Mach-O relocation has only signed 24-bit
// addend. For large symbols, we generate "label" symbols in the middle, so
// that relocations can target them with smaller addends.
- if !ctxt.IsDarwin() || !ctxt.IsExternal() {
+ // On Windows, we only get 21 bits, again (presumably) signed.
+ if !ctxt.IsDarwin() && !ctxt.IsWindows() || !ctxt.IsExternal() {
return
}
- big := false
- for _, seg := range ld.Segments {
- if seg.Length >= machoRelocLimit {
- big = true
- break
- }
+ limit := int64(machoRelocLimit)
+ if ctxt.IsWindows() {
+ limit = peRelocLimit
}
- if !big {
- return // skip work if nothing big
+
+ if ctxt.IsDarwin() {
+ big := false
+ for _, seg := range ld.Segments {
+ if seg.Length >= machoRelocLimit {
+ big = true
+ break
+ }
+ }
+ if !big {
+ return // skip work if nothing big
+ }
}
- // addLabelSyms adds "label" symbols at s+machoRelocLimit, s+2*machoRelocLimit, etc.
- addLabelSyms := func(s loader.Sym, sz int64) {
+ // addLabelSyms adds "label" symbols at s+limit, s+2*limit, etc.
+ addLabelSyms := func(s loader.Sym, limit, sz int64) {
v := ldr.SymValue(s)
- for off := int64(machoRelocLimit); off < sz; off += machoRelocLimit {
- p := ldr.LookupOrCreateSym(machoLabelName(ldr, s, off), ldr.SymVersion(s))
+ for off := limit; off < sz; off += limit {
+ p := ldr.LookupOrCreateSym(offsetLabelName(ldr, s, off), ldr.SymVersion(s))
ldr.SetAttrReachable(p, true)
ldr.SetSymValue(p, v+off)
ldr.SetSymSect(p, ldr.SymSect(s))
- ld.AddMachoSym(ldr, p)
- //fmt.Printf("gensymlate %s %x\n", ldr.SymName(p), ldr.SymValue(p))
+ if ctxt.IsDarwin() {
+ ld.AddMachoSym(ldr, p)
+ } else if ctxt.IsWindows() {
+ ld.AddPELabelSym(ldr, p)
+ } else {
+ panic("missing case in gensymlate")
+ }
+ // fmt.Printf("gensymlate %s %x\n", ldr.SymName(p), ldr.SymValue(p))
}
}
continue
}
if ldr.SymType(s) == sym.STEXT {
- continue // we don't target the middle of a function
+ if ctxt.IsDarwin() || ctxt.IsWindows() {
+ // Cannot relocate into middle of function.
+ // Generate symbol names for every offset we need in duffcopy/duffzero (only 64 each).
+ switch ldr.SymName(s) {
+ case "runtime.duffcopy":
+ addLabelSyms(s, 8, 8*64)
+ case "runtime.duffzero":
+ addLabelSyms(s, 4, 4*64)
+ }
+ }
+ continue // we don't target the middle of other functions
}
sz := ldr.SymSize(s)
- if sz <= machoRelocLimit {
+ if sz <= limit {
continue
}
- addLabelSyms(s, sz)
+ addLabelSyms(s, limit, sz)
}
// Also for carrier symbols (for which SymSize is 0)
for _, ss := range ld.CarrierSymByType {
- if ss.Sym != 0 && ss.Size > machoRelocLimit {
- addLabelSyms(ss.Sym, ss.Size)
+ if ss.Sym != 0 && ss.Size > limit {
+ addLabelSyms(ss.Sym, limit, ss.Size)
}
}
}
-// machoLabelName returns the name of the "label" symbol used for a
-// relocation targeting s+off. The label symbols is used on darwin
-// when external linking, so that the addend fits in a Mach-O relocation.
-func machoLabelName(ldr *loader.Loader, s loader.Sym, off int64) string {
- return fmt.Sprintf("%s.%d", ldr.SymExtname(s), off/machoRelocLimit)
+// offsetLabelName returns the name of the "label" symbol used for a
+// relocation targeting s+off. The label symbols is used on Darwin/Windows
+// when external linking, so that the addend fits in a Mach-O/PE relocation.
+func offsetLabelName(ldr *loader.Loader, s loader.Sym, off int64) string {
+ if off>>20<<20 == off {
+ return fmt.Sprintf("%s+%dMB", ldr.SymExtname(s), off>>20)
+ }
+ return fmt.Sprintf("%s+%d", ldr.SymExtname(s), off)
}