[AIX] Fixed malformed big archive when total archive file size is large than 4Gbytes

[DiggerLin]

Summary

1. we use the unsigned type for NextOffset,PrevOffset ,GlobalSymbolOffset , MemberTableSize, it will caused a malform big archive when the archive file size is large than 4G.
2. also fix a NFC comment on https://reviews.llvm.org/D142479#inline-1443927

[jhenderson]

Sorry for not getting around to reviewing many of your patches. I'm very heavily loaded with my regular work commitments, and will be for the next couple of weeks at least. I'm just trying to review smaller patches in the meantime.

llvm/lib/Object/ArchiveWriter.cpp

708

Why is uint16_t appropriate here? I don't think it's unfeasible for an archive to several several hundred thousand members in particularly big project. I'd stick with uint32_t unless this value directly matches up with a file format member that restricts it to uint16_t.

[DiggerLin]

llvm/lib/Object/ArchiveWriter.cpp

708

According to the definition of getSymbols() function , it should be uint16_t Index.

https://github.com/llvm/llvm-project/blob/main/llvm/lib/Object/ArchiveWriter.cpp#L582

static Expected<std::vector<unsigned>>
getSymbols(MemoryBufferRef Buf, uint16_t Index, raw_ostream &SymNames,

SymMap *SymMap, bool &HasObject)

https://github.com/llvm/llvm-project/blob/main/llvm/lib/Object/ArchiveWriter.cpp#L50

struct SymMap {

bool UseECMap;
std::map<std::string, uint16_t> Map;
std::map<std::string, uint16_t> ECMap;

};

[DiggerLin]

In D150462#4341258, @jhenderson wrote:

Sorry for not getting around to reviewing many of your patches. I'm very heavily loaded with my regular work commitments, and will be for the next couple of weeks at least. I'm just trying to review smaller patches in the meantime.

Hi James, Please don't worry about the delay in reviewing the patches. . I completely understand your work load , and I'm grateful for any time you can spare. thank you very much for your time and your professional comments.

[jhenderson]

Thanks for the explanation. LGTM.

llvm/lib/Object/ArchiveWriter.cpp

printBSDMemberHeader(raw_ostream &Out, uint64_t Pos, StringRef Name,
   while (Pad--)
     Out.write(uint8_t(0));
 }
 
 static void
 printBigArchiveMemberHeader(raw_ostream &Out, StringRef Name,
                             const sys::TimePoint<std::chrono::seconds> &ModTime,
                             unsigned UID, unsigned GID, unsigned Perms,
-                            uint64_t Size, unsigned PrevOffset,
-                            unsigned NextOffset) {
+                            uint64_t Size, uint64_t PrevOffset,
+                            uint64_t NextOffset) {
   unsigned NameLen = Name.size();
 
   printWithSpacePadding(Out, Size, 20);           // File member size
   printWithSpacePadding(Out, NextOffset, 20);     // Next member header offset
   printWithSpacePadding(Out, PrevOffset, 20); // Previous member header offset
   printWithSpacePadding(Out, sys::toTimeT(ModTime), 12); // File member date
   // The big archive format has 12 chars for uid and gid.
   printWithSpacePadding(Out, UID % 1000000000000, 12);   // UID
if (UniqueTimestamps) {
     for (const NewArchiveMember &M : NewMembers)
       FilenameCount[M.MemberName]++;
     for (auto &Entry : FilenameCount)
       Entry.second = Entry.second > 1 ? 1 : 0;
   }
 
   // The big archive format needs to know the offset of the previous member
   // header.
-  unsigned PrevOffset = 0, Index = 0;
+  uint64_t PrevOffset = 0;
+  uint16_t Index = 0;
   for (const NewArchiveMember &M : NewMembers) {
     std::string Header;
     raw_string_ostream Out(Header);
 
     MemoryBufferRef Buf = M.Buf->getMemBufferRef();
     StringRef Data = Thin ? "" : Buf.getBuffer();
 
     Index++;
for (const NewArchiveMember &M : NewMembers) {
     if (Size > object::Archive::MaxMemberSize) {
       std::string StringMsg =
           "File " + M.MemberName.str() + " exceeds size limit";
       return make_error<object::GenericBinaryError>(
           std::move(StringMsg), object::object_error::parse_failed);
     }
 
     if (isAIXBigArchive(Kind)) {
-      unsigned NextOffset = Pos + sizeof(object::BigArMemHdrType) +
+      uint64_t NextOffset = Pos + sizeof(object::BigArMemHdrType) +
                             alignTo(M.MemberName.size(), 2) + alignTo(Size, 2);
       printBigArchiveMemberHeader(Out, M.MemberName, ModTime, M.UID, M.GID,
                                   M.Perms, Size, PrevOffset, NextOffset);
       PrevOffset = Pos;
     } else {
       printMemberHeader(Out, Pos, StringTable, MemberNames, Kind, Thin, M,
                         ModTime, Size);
     }
for (size_t I = 0, Size = NewMembers.size(); I != Size; ++I) {
       // File member name ended with "`\n". The length is included in
       // BigArMemHdrType.
       MemberEndOffset += sizeof(object::BigArMemHdrType) +
                              alignTo(Data[I].Data.size(), 2) +
                              alignTo(Member.MemberName.size(), 2);
     }
 
     // AIX member table size.
-    unsigned MemberTableSize = 20 + // Number of members field
+    uint64_t MemberTableSize = 20 + // Number of members field
                                20 * MemberOffsets.size() +
                                MemberTableNameStrTblSize;
 
-    unsigned GlobalSymbolOffset =
+    uint64_t GlobalSymbolOffset =
         (WriteSymtab && NumSyms > 0)
             ? LastMemberEndOffset +
                   alignTo(sizeof(object::BigArMemHdrType) + MemberTableSize, 2)
             : 0;
 
     // Fixed Sized Header.
     printWithSpacePadding(Out, NewMembers.size() ? LastMemberEndOffset : 0,
                           20); // Offset to member table
     // If there are no file members in the archive, there will be no global
     // symbol table.
-    printWithSpacePadding(Out, NewMembers.size() ? GlobalSymbolOffset : 0, 20);
+    printWithSpacePadding(Out, GlobalSymbolOffset, 20);
     printWithSpacePadding(
         Out, 0,
         20); // Offset to 64 bits global symbol table - Not supported yet
     printWithSpacePadding(
         Out, NewMembers.size() ? sizeof(object::BigArchive::FixLenHdr) : 0,
         20); // Offset to first archive member
     printWithSpacePadding(Out, NewMembers.size() ? LastMemberHeaderOffset : 0,
                           20); // Offset to last archive member