[llvm] r273373 - llvm-ar: be more clever about default format

[Rafael Espíndola via llvm-commits]

testcase? :-)

On 22 June 2016 at 00:03, Saleem Abdulrasool via llvm-commits
<llvm-commits at lists.llvm.org> wrote:
> Author: compnerd
> Date: Tue Jun 21 23:03:28 2016
> New Revision: 273373
>
> URL: http://llvm.org/viewvc/llvm-project?rev=273373&view=rev
> Log:
> llvm-ar: be more clever about default format
>
> Try to be more clever about selecting the default format.  When an existing
> archive is used, use the type of the archive to determine the format.  When
> existing members are present, use the first member's format to determine the
> format to use.  If we are creating an empty archive (MRI mode) or are adding
> non-object members, default to the current behaviour of using the host type due
> to the lack of a better alternative.  This aids in cross-compilation on Darwin
> to non-Darwin platforms which rely on GNU format archives.
>
> Modified:
>     llvm/trunk/tools/llvm-ar/llvm-ar.cpp
>
> Modified: llvm/trunk/tools/llvm-ar/llvm-ar.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-ar/llvm-ar.cpp?rev=273373&r1=273372&r2=273373&view=diff
> ==============================================================================
> --- llvm/trunk/tools/llvm-ar/llvm-ar.cpp (original)
> +++ llvm/trunk/tools/llvm-ar/llvm-ar.cpp Tue Jun 21 23:03:28 2016
> @@ -19,6 +19,7 @@
>  #include "llvm/LibDriver/LibDriver.h"
>  #include "llvm/Object/Archive.h"
>  #include "llvm/Object/ArchiveWriter.h"
> +#include "llvm/Object/MachO.h"
>  #include "llvm/Object/ObjectFile.h"
>  #include "llvm/Support/CommandLine.h"
>  #include "llvm/Support/Errc.h"
> @@ -575,21 +576,86 @@ computeNewArchiveMembers(ArchiveOperatio
>    return Ret;
>  }
>
> +static object::Archive::Kind getDefaultForHost() {
> +  return Triple(sys::getProcessTriple()).isOSDarwin() ? object::Archive::K_BSD
> +                                                      : object::Archive::K_GNU;
> +}
> +
> +static object::Archive::Kind
> +getKindFromMember(const NewArchiveIterator &Member) {
> +  if (Member.isNewMember()) {
> +    object::Archive::Kind Kind = getDefaultForHost();
> +
> +    sys::fs::file_status Status;
> +    if (auto OptionalFD = Member.getFD(Status)) {
> +      auto OptionalMB = MemoryBuffer::getOpenFile(*OptionalFD, Member.getName(),
> +                                                  Status.getSize(), false);
> +      if (OptionalMB) {
> +        MemoryBufferRef MemoryBuffer = (*OptionalMB)->getMemBufferRef();
> +
> +        Expected<std::unique_ptr<object::ObjectFile>> OptionalObject =
> +            object::ObjectFile::createObjectFile(MemoryBuffer);
> +
> +        if (OptionalObject)
> +          Kind = isa<object::MachOObjectFile>(**OptionalObject)
> +              ? object::Archive::K_BSD
> +              : object::Archive::K_GNU;
> +
> +        // squelch the error in case we had a non-object file
> +        consumeError(OptionalObject.takeError());
> +      }
> +
> +      if (close(*OptionalFD) != 0)
> +        failIfError(std::error_code(errno, std::generic_category()),
> +                    "failed to close file");
> +    }
> +
> +    return Kind;
> +  } else {
> +    const object::Archive::Child &OldMember = Member.getOld();
> +    if (OldMember.getParent()->isThin())
> +      return object::Archive::Kind::K_GNU;
> +
> +    auto OptionalMB = OldMember.getMemoryBufferRef();
> +    failIfError(OptionalMB.getError());
> +
> +    Expected<std::unique_ptr<object::ObjectFile>> OptionalObject =
> +        object::ObjectFile::createObjectFile(*OptionalMB);
> +
> +    if (OptionalObject)
> +      return isa<object::MachOObjectFile>(*OptionalObject->get())
> +                 ? object::Archive::K_BSD
> +                 : object::Archive::K_GNU;
> +
> +    // squelch the error in case we had a non-object file
> +    consumeError(OptionalObject.takeError());
> +    return getDefaultForHost();
> +  }
> +}
> +
>  static void
>  performWriteOperation(ArchiveOperation Operation,
>                        object::Archive *OldArchive,
>                        std::unique_ptr<MemoryBuffer> OldArchiveBuf,
>                        std::vector<NewArchiveIterator> *NewMembersP) {
> +  std::vector<NewArchiveIterator> NewMembers;
> +  if (!NewMembersP)
> +    NewMembers = computeNewArchiveMembers(Operation, OldArchive);
> +
>    object::Archive::Kind Kind;
>    switch (FormatOpt) {
> -  case Default: {
> -    Triple T(sys::getProcessTriple());
> -    if (T.isOSDarwin() && !Thin)
> -      Kind = object::Archive::K_BSD;
> -    else
> +  case Default:
> +    if (Thin)
>        Kind = object::Archive::K_GNU;
> +    else if (OldArchive)
> +      Kind = OldArchive->kind();
> +    else if (NewMembersP)
> +      Kind = NewMembersP->size() ? getKindFromMember(NewMembersP->front())
> +                                 : getDefaultForHost();
> +    else
> +      Kind = NewMembers.size() ? getKindFromMember(NewMembers.front())
> +                               : getDefaultForHost();
>      break;
> -  }
>    case GNU:
>      Kind = object::Archive::K_GNU;
>      break;
> @@ -599,18 +665,10 @@ performWriteOperation(ArchiveOperation O
>      Kind = object::Archive::K_BSD;
>      break;
>    }
> -  if (NewMembersP) {
> -    std::pair<StringRef, std::error_code> Result = writeArchive(
> -        ArchiveName, *NewMembersP, Symtab, Kind, Deterministic, Thin,
> -        std::move(OldArchiveBuf));
> -    failIfError(Result.second, Result.first);
> -    return;
> -  }
> -  std::vector<NewArchiveIterator> NewMembers =
> -      computeNewArchiveMembers(Operation, OldArchive);
> -  auto Result =
> -      writeArchive(ArchiveName, NewMembers, Symtab, Kind, Deterministic, Thin,
> -      std::move(OldArchiveBuf));
> +
> +  std::pair<StringRef, std::error_code> Result =
> +      writeArchive(ArchiveName, NewMembersP ? *NewMembersP : NewMembers, Symtab,
> +                   Kind, Deterministic, Thin, std::move(OldArchiveBuf));
>    failIfError(Result.second, Result.first);
>  }
>
>
>
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