1 files changed, 128 insertions, 0 deletions
diff --git a/src/cmd/oldlink/internal/sym/reloc.go b/src/cmd/oldlink/internal/sym/reloc.go
new file mode 100644
index 0000000000..4809db8c80
--- /dev/null
+++ b/src/cmd/oldlink/internal/sym/reloc.go
@@ -0,0 +1,128 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package sym
+
+import (
+	"cmd/internal/objabi"
+	"cmd/internal/sys"
+	"debug/elf"
+)
+
+// Reloc is a relocation.
+//
+// The typical Reloc rewrites part of a symbol at offset Off to address Sym.
+// A Reloc is stored in a slice on the Symbol it rewrites.
+//
+// Relocations are generated by the compiler as the type
+// cmd/internal/obj.Reloc, which is encoded into the object file wire
+// format and decoded by the linker into this type. A separate type is
+// used to hold linker-specific state about the relocation.
+//
+// Some relocations are created by cmd/link.
+type Reloc struct {
+	Off       int32            // offset to rewrite
+	Siz       uint8            // number of bytes to rewrite, 1, 2, or 4
+	Done      bool             // set to true when relocation is complete
+	Type      objabi.RelocType // the relocation type
+	Add       int64            // addend
+	Sym       *Symbol          // symbol the relocation addresses
+	*relocExt                  // extra fields (see below), may be nil, call InitExt before use
+}
+
+// relocExt contains extra fields in Reloc that are used only in
+// certain cases.
+type relocExt struct {
+	Xadd    int64        // addend passed to external linker
+	Xsym    *Symbol      // symbol passed to external linker
+	Variant RelocVariant // variation on Type, currently used only on PPC64 and S390X
+}
+
+func (r *Reloc) InitExt() {
+	if r.relocExt == nil {
+		r.relocExt = new(relocExt)
+	}
+}
+
+// RelocVariant is a linker-internal variation on a relocation.
+type RelocVariant uint8
+
+const (
+	RV_NONE RelocVariant = iota
+	RV_POWER_LO
+	RV_POWER_HI
+	RV_POWER_HA
+	RV_POWER_DS
+
+	// RV_390_DBL is a s390x-specific relocation variant that indicates that
+	// the value to be placed into the relocatable field should first be
+	// divided by 2.
+	RV_390_DBL
+
+	RV_CHECK_OVERFLOW RelocVariant = 1 << 7
+	RV_TYPE_MASK      RelocVariant = RV_CHECK_OVERFLOW - 1
+)
+
+func RelocName(arch *sys.Arch, r objabi.RelocType) string {
+	// We didn't have some relocation types at Go1.4.
+	// Uncomment code when we include those in bootstrap code.
+
+	switch {
+	case r >= objabi.MachoRelocOffset: // Mach-O
+		// nr := (r - objabi.MachoRelocOffset)>>1
+		// switch ctxt.Arch.Family {
+		// case sys.AMD64:
+		// 	return macho.RelocTypeX86_64(nr).String()
+		// case sys.ARM:
+		// 	return macho.RelocTypeARM(nr).String()
+		// case sys.ARM64:
+		// 	return macho.RelocTypeARM64(nr).String()
+		// case sys.I386:
+		// 	return macho.RelocTypeGeneric(nr).String()
+		// default:
+		// 	panic("unreachable")
+		// }
+	case r >= objabi.ElfRelocOffset: // ELF
+		nr := r - objabi.ElfRelocOffset
+		switch arch.Family {
+		case sys.AMD64:
+			return elf.R_X86_64(nr).String()
+		case sys.ARM:
+			return elf.R_ARM(nr).String()
+		case sys.ARM64:
+			return elf.R_AARCH64(nr).String()
+		case sys.I386:
+			return elf.R_386(nr).String()
+		case sys.MIPS, sys.MIPS64:
+			return elf.R_MIPS(nr).String()
+		case sys.PPC64:
+			return elf.R_PPC64(nr).String()
+		case sys.S390X:
+			return elf.R_390(nr).String()
+		default:
+			panic("unreachable")
+		}
+	}
+
+	return r.String()
+}
+
+// RelocByOff implements sort.Interface for sorting relocations by offset.
+type RelocByOff []Reloc
+
+func (x RelocByOff) Len() int { return len(x) }
+
+func (x RelocByOff) Swap(i, j int) { x[i], x[j] = x[j], x[i] }
+
+func (x RelocByOff) Less(i, j int) bool {
+	a := &x[i]
+	b := &x[j]
+	if a.Off < b.Off {
+		return true
+	}
+	if a.Off > b.Off {
+		return false
+	}
+	return false
+}