Start adding support for writing archives in BSD format.

No support for the symbol table yet (but will hopefully add it today).
We always use the long filename format so that we can align the member,
which is an advantage of the BSD format.

llvm-svn: 241721

include/llvm/Object/ArchiveWriter.h

@@ -44,8 +44,7 @@ public:
 
 std::pair<StringRef, std::error_code>
 writeArchive(StringRef ArcName, std::vector<NewArchiveIterator> &NewMembers,
-             bool WriteSymtab);
-
+             bool WriteSymtab, object::Archive::Kind Kind);
 }
 
 #endif

lib/LibDriver/LibDriver.cpp

@@ -139,8 +139,10 @@ int llvm::libDriverMain(llvm::ArrayRef<const char*> ArgsArr) {
                          llvm::sys::path::filename(Arg->getValue()));
   }
 
-  std::pair<StringRef, std::error_code> Result = llvm::writeArchive(
-      getOutputPath(&Args, Members[0]), Members, /*WriteSymtab=*/true);
+  std::pair<StringRef, std::error_code> Result =
+      llvm::writeArchive(getOutputPath(&Args, Members[0]), Members,
+                         /*WriteSymtab=*/true, object::Archive::K_GNU);
+
   if (Result.second) {
     if (Result.first.empty())
       Result.first = ArgsArr[0];

lib/Object/ArchiveWriter.cpp

@@ -117,10 +117,25 @@ static void printMemberHeader(raw_fd_ostream &Out, StringRef Name,
 }
 
 static void
-printMemberHeader(raw_fd_ostream &Out, StringRef Name,
+printMemberHeader(raw_fd_ostream &Out, object::Archive::Kind Kind,
+                  StringRef Name,
                   std::vector<unsigned>::iterator &StringMapIndexIter,
                   const sys::TimeValue &ModTime, unsigned UID, unsigned GID,
                   unsigned Perms, unsigned Size) {
+  if (Kind == object::Archive::K_BSD) {
+    uint64_t PosAfterHeader = Out.tell() + 60 + Name.size();
+    // Pad so that even 64 bit object files are aligned.
+    unsigned Pad = OffsetToAlignment(PosAfterHeader, 8);
+    unsigned NameWithPadding = Name.size() + Pad;
+    printWithSpacePadding(Out, Twine("#1/") + Twine(NameWithPadding), 16);
+    printRestOfMemberHeader(Out, ModTime, UID, GID, Perms,
+                            NameWithPadding + Size);
+    Out << Name;
+    assert(PosAfterHeader == Out.tell());
+    while (Pad--)
+      Out.write(uint8_t(0));
+    return;
+  }
   if (Name.size() < 16) {
     printMemberHeader(Out, Name, ModTime, UID, GID, Perms, Size);
     return;
@@ -160,9 +175,13 @@ static void writeStringTable(raw_fd_ostream &Out,
 
 // Returns the offset of the first reference to a member offset.
 static ErrorOr<unsigned>
-writeSymbolTable(raw_fd_ostream &Out, ArrayRef<NewArchiveIterator> Members,
+writeSymbolTable(raw_fd_ostream &Out, object::Archive::Kind Kind,
+                 ArrayRef<NewArchiveIterator> Members,
                  ArrayRef<MemoryBufferRef> Buffers,
                  std::vector<unsigned> &MemberOffsetRefs) {
+  if (Kind != object::Archive::K_GNU)
+    return 0;
+
   unsigned StartOffset = 0;
   unsigned MemberNum = 0;
   std::string NameBuf;
@@ -222,7 +241,7 @@ writeSymbolTable(raw_fd_ostream &Out, ArrayRef<NewArchiveIterator> Members,
 std::pair<StringRef, std::error_code>
 llvm::writeArchive(StringRef ArcName,
                    std::vector<NewArchiveIterator> &NewMembers,
-                   bool WriteSymtab) {
+                   bool WriteSymtab, object::Archive::Kind Kind) {
   SmallString<128> TmpArchive;
   int TmpArchiveFD;
   if (auto EC = sys::fs::createUniqueFile(ArcName + ".temp-archive-%%%%%%%.a",
@@ -274,14 +293,15 @@ llvm::writeArchive(StringRef ArcName,
   unsigned MemberReferenceOffset = 0;
   if (WriteSymtab) {
     ErrorOr<unsigned> MemberReferenceOffsetOrErr =
-        writeSymbolTable(Out, NewMembers, Members, MemberOffsetRefs);
+        writeSymbolTable(Out, Kind, NewMembers, Members, MemberOffsetRefs);
     if (auto EC = MemberReferenceOffsetOrErr.getError())
       return std::make_pair(ArcName, EC);
     MemberReferenceOffset = MemberReferenceOffsetOrErr.get();
   }
 
   std::vector<unsigned> StringMapIndexes;
-  writeStringTable(Out, NewMembers, StringMapIndexes);
+  if (Kind != object::Archive::K_BSD)
+    writeStringTable(Out, NewMembers, StringMapIndexes);
 
   unsigned MemberNum = 0;
   unsigned NewMemberNum = 0;
@@ -296,13 +316,13 @@ llvm::writeArchive(StringRef ArcName,
     if (I.isNewMember()) {
       StringRef FileName = I.getNew();
       const sys::fs::file_status &Status = NewMemberStatus[NewMemberNum++];
-      printMemberHeader(Out, sys::path::filename(FileName), StringMapIndexIter,
-                        Status.getLastModificationTime(), Status.getUser(),
-                        Status.getGroup(), Status.permissions(),
-                        Status.getSize());
+      printMemberHeader(Out, Kind, sys::path::filename(FileName),
+                        StringMapIndexIter, Status.getLastModificationTime(),
+                        Status.getUser(), Status.getGroup(),
+                        Status.permissions(), Status.getSize());
     } else {
       object::Archive::child_iterator OldMember = I.getOld();
-      printMemberHeader(Out, I.getName(), StringMapIndexIter,
+      printMemberHeader(Out, Kind, I.getName(), StringMapIndexIter,
                         OldMember->getLastModified(), OldMember->getUID(),
                         OldMember->getGID(), OldMember->getAccessMode(),
                         OldMember->getSize());

test/Object/archive-format.test

@@ -17,3 +17,13 @@ CHECK-NEXT: 0123456789abcdef/
 CHECK-NEXT: 0123456789abcde/{{................................}}4         `
 CHECK-NEXT: bar./0              {{................................}}4         `
 CHECK-NEXT: zed.
+
+RUN: rm -f test-bsd.a
+RUN: llvm-ar --format=bsd rc test-bsd.a 0123456789abcde 0123456789abcdef
+RUN: cat test-bsd.a | FileCheck -strict-whitespace --check-prefix=BSD %s
+
+BSD:      !<arch>
+BSD-NEXT: #1/20           {{..............................}}  24        `
+BSD-NEXT: 0123456789abcde{{.....}}bar.
+BSD-SAME: #1/16           {{..............................}}  20        `
+BSD-NEXT: 0123456789abcdefzed.

tools/llvm-ar/llvm-ar.cpp

@@ -70,6 +70,16 @@ static cl::list<std::string>
 
 static cl::opt<bool> MRI("M", cl::desc(""));
 
+namespace {
+enum Format { Default, GNU, BSD };
+}
+
+static cl::opt<Format>
+    FormatOpt("format", cl::desc("Archive format to create"),
+              cl::values(clEnumValN(Default, "defalut", "default"),
+                         clEnumValN(GNU, "gnu", "gnu"),
+                         clEnumValN(BSD, "bsd", "bsd"), clEnumValEnd));
+
 std::string Options;
 
 // Provide additional help output explaining the operations and modifiers of
@@ -539,15 +549,27 @@ computeNewArchiveMembers(ArchiveOperation Operation,
 static void
 performWriteOperation(ArchiveOperation Operation, object::Archive *OldArchive,
                       std::vector<NewArchiveIterator> *NewMembersP) {
+  object::Archive::Kind Kind;
+  switch (FormatOpt) {
+  case Default:
+    // FIXME: change as the support for other formats improve.
+    Kind = object::Archive::K_GNU;
+  case GNU:
+    Kind = object::Archive::K_GNU;
+    break;
+  case BSD:
+    Kind = object::Archive::K_BSD;
+    break;
+  }
   if (NewMembersP) {
     std::pair<StringRef, std::error_code> Result =
-        writeArchive(ArchiveName, *NewMembersP, Symtab);
+        writeArchive(ArchiveName, *NewMembersP, Symtab, Kind);
     failIfError(Result.second, Result.first);
     return;
   }
   std::vector<NewArchiveIterator> NewMembers =
       computeNewArchiveMembers(Operation, OldArchive);
-  auto Result = writeArchive(ArchiveName, NewMembers, Symtab);
+  auto Result = writeArchive(ArchiveName, NewMembers, Symtab, Kind);
   failIfError(Result.second, Result.first);
 }