cmd/link: introduce and use peFile and peStringTable

Change-Id: Icd13b32d35cde474c9292227471f916a64af88eb
Reviewed-on: https://go-review.googlesource.com/55257
Reviewed-by: Ian Lance Taylor <iant@golang.org>

diff --git a/src/cmd/link/internal/ld/pe.go b/src/cmd/link/internal/ld/pe.go
index caa3eabb511acc9ba210bc49d9ec015b3c096f0c..6c6758644fe02d6a90f5c9ef55ae5db29e3fcc10 100644 (file)
--- a/src/cmd/link/internal/ld/pe.go
+++ b/src/cmd/link/internal/ld/pe.go
@@ -328,8 +328,6 @@ var dosstub = []uint8{
 
 var rsrcsym *Symbol
 
-var strtbl []byte
-
 var PESECTHEADR int32
 
 var PEFILEHEADR int32
@@ -382,6 +380,42 @@ var dexport [1024]*Symbol
 
 var nexport int
 
+// peStringTable is a COFF string table.
+type peStringTable struct {
+       strings    []string
+       stringsLen int
+}
+
+// size resturns size of string table t.
+func (t *peStringTable) size() int {
+       // string table starts with 4-byte length at the beginning
+       return t.stringsLen + 4
+}
+
+// add adds string str to string table t.
+func (t *peStringTable) add(str string) int {
+       off := t.size()
+       t.strings = append(t.strings, str)
+       t.stringsLen += len(str) + 1 // each string will have 0 appended to it
+       return off
+}
+
+// write writes string table t into the output file.
+func (t *peStringTable) write() {
+       Lputl(uint32(t.size()))
+       for _, s := range t.strings {
+               Cwritestring(s)
+               Cput(0)
+       }
+}
+
+// peFile is used to build COFF file.
+type peFile struct {
+       stringTable peStringTable
+}
+
+var pefile peFile
+
 func addpesectionWithLongName(ctxt *Link, shortname, longname string, sectsize int, filesize int) *IMAGE_SECTION_HEADER {
        if pensect == 16 {
                Errorf(nil, "too many sections")
@@ -407,6 +441,7 @@ func addpesectionWithLongName(ctxt *Link, shortname, longname string, sectsize i
 func addpesection(ctxt *Link, name string, sectsize int, filesize int) *IMAGE_SECTION_HEADER {
        return addpesectionWithLongName(ctxt, name, name, sectsize, filesize)
 }
+
 func chksectoff(ctxt *Link, h *IMAGE_SECTION_HEADER, off int64) {
        if off != int64(h.PointerToRawData) {
                Errorf(nil, "%s.PointerToRawData = %#x, want %#x", cstring(h.Name[:]), uint64(int64(h.PointerToRawData)), uint64(off))
@@ -942,13 +977,6 @@ func (ctxt *Link) dope() {
        initdynexport(ctxt)
 }
 
-func strtbladd(name string) int {
-       off := len(strtbl) + 4 // offset includes 4-byte length at beginning of table
-       strtbl = append(strtbl, name...)
-       strtbl = append(strtbl, 0)
-       return off
-}
-
 /*
  * For more than 8 characters section names, name contains a slash (/) that is
  * followed by an ASCII representation of a decimal number that is an offset into
@@ -961,7 +989,7 @@ func newPEDWARFSection(ctxt *Link, name string, size int64) *IMAGE_SECTION_HEADE
                return nil
        }
 
-       off := strtbladd(name)
+       off := pefile.stringTable.add(name)
        s := fmt.Sprintf("/%d", off)
        h := addpesectionWithLongName(ctxt, s, name, int(size), int(size))
        h.Characteristics = IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_DISCARDABLE
@@ -978,7 +1006,7 @@ func writePESymTableRecords(ctxt *Link) int {
                // write COFF symbol table record
                if len(s.Name) > 8 {
                        Lputl(0)
-                       Lputl(uint32(strtbladd(s.Name)))
+                       Lputl(uint32(pefile.stringTable.add(s.Name)))
                } else {
                        strnput(s.Name, 8)
                }
@@ -1071,7 +1099,7 @@ func addpesymtable(ctxt *Link) {
        }
 
        // update COFF file header and section table
-       size := len(strtbl) + 4 + 18*symcnt
+       size := pefile.stringTable.size() + 18*symcnt
        var h *IMAGE_SECTION_HEADER
        if Linkmode != LinkExternal {
                // We do not really need .symtab for go.o, and if we have one, ld
@@ -1084,10 +1112,7 @@ func addpesymtable(ctxt *Link) {
        fh.NumberOfSymbols = uint32(symcnt)
 
        // write COFF string table
-       Lputl(uint32(len(strtbl)) + 4)
-       for i := 0; i < len(strtbl); i++ {
-               Cput(strtbl[i])
-       }
+       pefile.stringTable.write()
        if Linkmode != LinkExternal {
                strnput("", int(h.SizeOfRawData-uint32(size)))
        }