cmd/link: define a variable for the target platform's elf relocation type

Rather than having half a dozen switch statements. Also remove some c2go dregs.

Change-Id: I19af5b64f73369126020e15421c34cad5bbcfbf8
Reviewed-on: https://go-review.googlesource.com/21442
Reviewed-by: Ian Lance Taylor <iant@golang.org>

diff --git a/src/cmd/link/internal/ld/elf.go b/src/cmd/link/internal/ld/elf.go
index cf518a799e1a4d9df194e79d4a9efe780a67983c..ffb7c4bddefa43ae3a2e25eda83c1e2892e1be3d 100644 (file)
--- a/src/cmd/link/internal/ld/elf.go
+++ b/src/cmd/link/internal/ld/elf.go
@@ -9,7 +9,6 @@ import (
        "crypto/sha1"
        "encoding/binary"
        "encoding/hex"
-       "fmt"
        "path/filepath"
        "sort"
        "strings"
@@ -832,19 +831,22 @@ const (
        NSECT = 48
 )
 
-var Iself bool
+var (
+       Iself bool
 
-var Nelfsym int = 1
+       Nelfsym int = 1
 
-var elf64 bool
+       elf64 bool
+       // Either ".rel" or ".rela" depending on which type of relocation the
+       // target platform uses.
+       elfRelType string
 
-var ehdr ElfEhdr
+       ehdr ElfEhdr
+       phdr [NSECT]*ElfPhdr
+       shdr [NSECT]*ElfShdr
 
-var phdr [NSECT]*ElfPhdr
-
-var shdr [NSECT]*ElfShdr
-
-var interp string
+       interp string
+)
 
 type Elfstring struct {
        s   string
@@ -864,6 +866,13 @@ var buildinfo []byte
 func Elfinit() {
        Iself = true
 
+       switch Thearch.Thechar {
+       case '0', '6', '7', '9', 'z':
+               elfRelType = ".rela"
+       default:
+               elfRelType = ".rel"
+       }
+
        switch Thearch.Thechar {
        // 64-bit architectures
        case '9', 'z':
@@ -1507,21 +1516,15 @@ func elfdynhash() {
                elfwritedynentsym(s, DT_VERSYM, Linklookup(Ctxt, ".gnu.version", 0))
        }
 
-       switch Thearch.Thechar {
-       case '0', '6', '7', '9', 'z':
-               sy := Linklookup(Ctxt, ".rela.plt", 0)
-               if sy.Size > 0 {
+       sy := Linklookup(Ctxt, elfRelType+".plt", 0)
+       if sy.Size > 0 {
+               if elfRelType == ".rela" {
                        Elfwritedynent(s, DT_PLTREL, DT_RELA)
-                       elfwritedynentsymsize(s, DT_PLTRELSZ, sy)
-                       elfwritedynentsym(s, DT_JMPREL, sy)
-               }
-       default:
-               sy := Linklookup(Ctxt, ".rel.plt", 0)
-               if sy.Size > 0 {
+               } else {
                        Elfwritedynent(s, DT_PLTREL, DT_REL)
-                       elfwritedynentsymsize(s, DT_PLTRELSZ, sy)
-                       elfwritedynentsym(s, DT_JMPREL, sy)
                }
+               elfwritedynentsymsize(s, DT_PLTRELSZ, sy)
+               elfwritedynentsym(s, DT_JMPREL, sy)
        }
 
        Elfwritedynent(s, DT_NULL, 0)
@@ -1645,19 +1648,14 @@ func elfshreloc(sect *Section) *ElfShdr {
                return nil
        }
 
-       var prefix string
        var typ int
-       switch Thearch.Thechar {
-       case '0', '6', '7', '9', 'z':
-               prefix = ".rela"
+       if elfRelType == ".rela" {
                typ = SHT_RELA
-       default:
-               prefix = ".rel"
+       } else {
                typ = SHT_REL
        }
 
-       buf := fmt.Sprintf("%s%s", prefix, sect.Name)
-       sh := elfshname(buf)
+       sh := elfshname(elfRelType + sect.Name)
        sh.type_ = uint32(typ)
        sh.entsize = uint64(Thearch.Regsize) * 2
        if typ == SHT_RELA {
@@ -1821,32 +1819,16 @@ func doelf() {
        if Linkmode == LinkExternal {
                Debug['d'] = 1
 
-               switch Thearch.Thechar {
-               case '0', '6', '7', '9', 'z':
-                       Addstring(shstrtab, ".rela.text")
-                       Addstring(shstrtab, ".rela.rodata")
-                       Addstring(shstrtab, ".rela"+relro_prefix+".typelink")
-                       Addstring(shstrtab, ".rela"+relro_prefix+".itablink")
-                       Addstring(shstrtab, ".rela"+relro_prefix+".gosymtab")
-                       Addstring(shstrtab, ".rela"+relro_prefix+".gopclntab")
-                       Addstring(shstrtab, ".rela.noptrdata")
-                       Addstring(shstrtab, ".rela.data")
-                       if UseRelro() {
-                               Addstring(shstrtab, ".rela.data.rel.ro")
-                       }
-
-               default:
-                       Addstring(shstrtab, ".rel.text")
-                       Addstring(shstrtab, ".rel.rodata")
-                       Addstring(shstrtab, ".rel"+relro_prefix+".typelink")
-                       Addstring(shstrtab, ".rel"+relro_prefix+".itablink")
-                       Addstring(shstrtab, ".rel"+relro_prefix+".gosymtab")
-                       Addstring(shstrtab, ".rel"+relro_prefix+".gopclntab")
-                       Addstring(shstrtab, ".rel.noptrdata")
-                       Addstring(shstrtab, ".rel.data")
-                       if UseRelro() {
-                               Addstring(shstrtab, ".rel.data.rel.ro")
-                       }
+               Addstring(shstrtab, elfRelType+".text")
+               Addstring(shstrtab, elfRelType+".rodata")
+               Addstring(shstrtab, elfRelType+relro_prefix+".typelink")
+               Addstring(shstrtab, elfRelType+relro_prefix+".itablink")
+               Addstring(shstrtab, elfRelType+relro_prefix+".gosymtab")
+               Addstring(shstrtab, elfRelType+relro_prefix+".gopclntab")
+               Addstring(shstrtab, elfRelType+".noptrdata")
+               Addstring(shstrtab, elfRelType+".data")
+               if UseRelro() {
+                       Addstring(shstrtab, elfRelType+".data.rel.ro")
                }
 
                // add a .note.GNU-stack section to mark the stack as non-executable
@@ -1869,12 +1851,7 @@ func doelf() {
 
        if hasinitarr {
                Addstring(shstrtab, ".init_array")
-               switch Thearch.Thechar {
-               case '0', '6', '7', '9', 'z':
-                       Addstring(shstrtab, ".rela.init_array")
-               default:
-                       Addstring(shstrtab, ".rel.init_array")
-               }
+               Addstring(shstrtab, elfRelType+".init_array")
        }
 
        if Debug['s'] == 0 {
@@ -1896,14 +1873,8 @@ func doelf() {
                Addstring(shstrtab, ".dynamic")
                Addstring(shstrtab, ".dynsym")
                Addstring(shstrtab, ".dynstr")
-               switch Thearch.Thechar {
-               case '0', '6', '7', '9', 'z':
-                       Addstring(shstrtab, ".rela")
-                       Addstring(shstrtab, ".rela.plt")
-               default:
-                       Addstring(shstrtab, ".rel")
-                       Addstring(shstrtab, ".rel.plt")
-               }
+               Addstring(shstrtab, elfRelType)
+               Addstring(shstrtab, elfRelType+".plt")
 
                Addstring(shstrtab, ".plt")
                Addstring(shstrtab, ".gnu.version")
@@ -1932,12 +1903,7 @@ func doelf() {
                dynstr := s
 
                /* relocation table */
-               switch Thearch.Thechar {
-               case '0', '6', '7', '9', 'z':
-                       s = Linklookup(Ctxt, ".rela", 0)
-               default:
-                       s = Linklookup(Ctxt, ".rel", 0)
-               }
+               s = Linklookup(Ctxt, elfRelType, 0)
                s.Attr |= AttrReachable
                s.Type = obj.SELFROSECT
 
@@ -1977,12 +1943,7 @@ func doelf() {
 
                Thearch.Elfsetupplt()
 
-               switch Thearch.Thechar {
-               case '0', '6', '7', '9', 'z':
-                       s = Linklookup(Ctxt, ".rela.plt", 0)
-               default:
-                       s = Linklookup(Ctxt, ".rel.plt", 0)
-               }
+               s = Linklookup(Ctxt, elfRelType+".plt", 0)
                s.Attr |= AttrReachable
                s.Type = obj.SELFROSECT
 
@@ -2014,12 +1975,11 @@ func doelf() {
                }
                elfwritedynentsym(s, DT_STRTAB, Linklookup(Ctxt, ".dynstr", 0))
                elfwritedynentsymsize(s, DT_STRSZ, Linklookup(Ctxt, ".dynstr", 0))
-               switch Thearch.Thechar {
-               case '0', '6', '7', '9', 'z':
+               if elfRelType == ".rela" {
                        elfwritedynentsym(s, DT_RELA, Linklookup(Ctxt, ".rela", 0))
                        elfwritedynentsymsize(s, DT_RELASZ, Linklookup(Ctxt, ".rela", 0))
                        Elfwritedynent(s, DT_RELAENT, ELF64RELASIZE)
-               default:
+               } else {
                        elfwritedynentsym(s, DT_REL, Linklookup(Ctxt, ".rel", 0))
                        elfwritedynentsymsize(s, DT_RELSZ, Linklookup(Ctxt, ".rel", 0))
                        Elfwritedynent(s, DT_RELENT, ELF32RELSIZE)
@@ -2314,8 +2274,7 @@ func Asmbelf(symo int64) {
                        shsym(sh, Linklookup(Ctxt, ".gnu.version_r", 0))
                }
 
-               switch eh.machine {
-               case EM_X86_64, EM_PPC64, EM_AARCH64, EM_S390:
+               if elfRelType == ".rela" {
                        sh := elfshname(".rela.plt")
                        sh.type_ = SHT_RELA
                        sh.flags = SHF_ALLOC
@@ -2332,8 +2291,7 @@ func Asmbelf(symo int64) {
                        sh.addralign = 8
                        sh.link = uint32(elfshname(".dynsym").shnum)
                        shsym(sh, Linklookup(Ctxt, ".rela", 0))
-
-               default:
+               } else {
                        sh := elfshname(".rel.plt")
                        sh.type_ = SHT_REL
                        sh.flags = SHF_ALLOC