cmd/internal/ld: handle TLS and imported symbols more regularly

For shared libraries we need to be more flexible in how these symbols
are handled (e.g. sometimes tlsg needs to be global, or you can get
a SDYNIMPORT symbol that has .Hide == true) so handling these cases
in genasmsym makes everything much more regular.

Even ignoring shared libraries, I think this is a bit cleaner.

Change-Id: If5beb093a261e79f4496183226e1765ee7aa6717
Reviewed-on: https://go-review.googlesource.com/8230
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

diff --git a/src/cmd/internal/ld/lib.go b/src/cmd/internal/ld/lib.go
index caca87c180c5e5e6a3b0aed6def586cb73e8bfc8..48fd8bc9562225d84924c16472e99ca47faacf4d 100644 (file)
--- a/src/cmd/internal/ld/lib.go
+++ b/src/cmd/internal/ld/lib.go
@@ -430,7 +430,6 @@ func loadlib() {
                tlsg.Type = STLSBSS
        }
        tlsg.Size = int64(Thearch.Ptrsize)
-       tlsg.Hide = 1
        tlsg.Reachable = true
        Ctxt.Tlsg = tlsg
 
@@ -1375,7 +1374,6 @@ func genasmsym(put func(*LSym, string, int, int64, int64, int, *LSym)) {
                                continue
                        }
                        put(s, s.Name, 'D', Symaddr(s), s.Size, int(s.Version), s.Gotype)
-                       continue
 
                case SBSS,
                        SNOPTRBSS:
@@ -1386,18 +1384,31 @@ func genasmsym(put func(*LSym, string, int, int64, int64, int, *LSym)) {
                                Diag("%s should not be bss (size=%d type=%d special=%d)", s.Name, int(len(s.P)), s.Type, s.Special)
                        }
                        put(s, s.Name, 'B', Symaddr(s), s.Size, int(s.Version), s.Gotype)
-                       continue
 
                case SFILE:
                        put(nil, s.Name, 'f', s.Value, 0, int(s.Version), nil)
-                       continue
 
                case SHOSTOBJ:
-                       if HEADTYPE == Hwindows {
+                       if HEADTYPE == Hwindows || Iself {
                                put(s, s.Name, 'U', s.Value, 0, int(s.Version), nil)
                        }
-                       continue
 
+               case SDYNIMPORT:
+                       if !s.Reachable {
+                               continue
+                       }
+                       put(s, s.Extname, 'U', 0, 0, int(s.Version), nil)
+
+               case STLSBSS:
+                       if Linkmode == LinkExternal && HEADTYPE != Hopenbsd {
+                               var type_ int
+                               if goos == "android" {
+                                       type_ = 'B'
+                               } else {
+                                       type_ = 't'
+                               }
+                               put(s, s.Name, type_, Symaddr(s), s.Size, int(s.Version), s.Gotype)
+                       }
                }
        }
 

diff --git a/src/cmd/internal/ld/symtab.go b/src/cmd/internal/ld/symtab.go
index e1ac864426c258bfac2e404a62035fda7310e8f4..e165c8c855d6f0b2fd38f98a801a50c77f1b363d 100644 (file)
--- a/src/cmd/internal/ld/symtab.go
+++ b/src/cmd/internal/ld/symtab.go
@@ -98,22 +98,34 @@ func putelfsym(x *LSym, s string, t int, addr int64, size int64, ver int, go_ *L
 
        case 'B':
                type_ = STT_OBJECT
+
+       case 'U':
+               type_ = STT_NOTYPE
+
+       case 't':
+               type_ = STT_TLS
        }
 
        xo := x
        for xo.Outer != nil {
                xo = xo.Outer
        }
-       if xo.Sect == nil {
-               Ctxt.Cursym = x
-               Diag("missing section in putelfsym")
-               return
-       }
 
-       if (xo.Sect.(*Section)).Elfsect == nil {
-               Ctxt.Cursym = x
-               Diag("missing ELF section in putelfsym")
-               return
+       var elfshnum int
+       if xo.Type == SDYNIMPORT || xo.Type == SHOSTOBJ {
+               elfshnum = SHN_UNDEF
+       } else {
+               if xo.Sect == nil {
+                       Ctxt.Cursym = x
+                       Diag("missing section in putelfsym")
+                       return
+               }
+               if (xo.Sect.(*Section)).Elfsect == nil {
+                       Ctxt.Cursym = x
+                       Diag("missing ELF section in putelfsym")
+                       return
+               }
+               elfshnum = ((xo.Sect.(*Section)).Elfsect.(*ElfShdr)).shnum
        }
 
        // One pass for each binding: STB_LOCAL, STB_GLOBAL,
@@ -128,7 +140,7 @@ func putelfsym(x *LSym, s string, t int, addr int64, size int64, ver int, go_ *L
        // to get the exported symbols put into the dynamic symbol table.
        // To avoid filling the dynamic table with lots of unnecessary symbols,
        // mark all Go symbols local (not global) in the final executable.
-       if Linkmode == LinkExternal && x.Cgoexport&CgoExportStatic == 0 {
+       if Linkmode == LinkExternal && x.Cgoexport&CgoExportStatic == 0 && elfshnum != SHN_UNDEF {
                bind = STB_LOCAL
        }
 
@@ -137,14 +149,14 @@ func putelfsym(x *LSym, s string, t int, addr int64, size int64, ver int, go_ *L
        }
 
        off := putelfstr(s)
-       if Linkmode == LinkExternal {
+       if Linkmode == LinkExternal && elfshnum != SHN_UNDEF {
                addr -= int64((xo.Sect.(*Section)).Vaddr)
        }
        other := STV_DEFAULT
        if x.Type&SHIDDEN != 0 {
                other = STV_HIDDEN
        }
-       putelfsyment(off, addr, size, bind<<4|type_&0xf, ((xo.Sect.(*Section)).Elfsect.(*ElfShdr)).shnum, other)
+       putelfsyment(off, addr, size, bind<<4|type_&0xf, elfshnum, other)
        x.Elfsym = int32(numelfsym)
        numelfsym++
 }
@@ -178,43 +190,9 @@ func Asmelfsym() {
        elfbind = STB_LOCAL
        genasmsym(putelfsym)
 
-       if Linkmode == LinkExternal && HEADTYPE != Hopenbsd {
-               s := Linklookup(Ctxt, "runtime.tlsg", 0)
-               if s.Sect == nil {
-                       Ctxt.Cursym = nil
-                       Diag("missing section for %s", s.Name)
-                       Errorexit()
-               }
-
-               if goos == "android" {
-                       // Android emulates runtime.tlsg as a regular variable.
-                       putelfsyment(putelfstr(s.Name), 0, s.Size, STB_LOCAL<<4|STT_OBJECT, ((s.Sect.(*Section)).Elfsect.(*ElfShdr)).shnum, 0)
-               } else {
-                       putelfsyment(putelfstr(s.Name), 0, s.Size, STB_LOCAL<<4|STT_TLS, ((s.Sect.(*Section)).Elfsect.(*ElfShdr)).shnum, 0)
-               }
-
-               s.Elfsym = int32(numelfsym)
-               numelfsym++
-       }
-
        elfbind = STB_GLOBAL
        elfglobalsymndx = numelfsym
        genasmsym(putelfsym)
-
-       var name string
-       for s := Ctxt.Allsym; s != nil; s = s.Allsym {
-               if s.Type != SHOSTOBJ && (s.Type != SDYNIMPORT || !s.Reachable) {
-                       continue
-               }
-               if s.Type == SDYNIMPORT {
-                       name = s.Extname
-               } else {
-                       name = s.Name
-               }
-               putelfsyment(putelfstr(name), 0, 0, STB_GLOBAL<<4|STT_NOTYPE, 0, 0)
-               s.Elfsym = int32(numelfsym)
-               numelfsym++
-       }
 }
 
 func putplan9sym(x *LSym, s string, t int, addr int64, size int64, ver int, go_ *LSym) {