[lld] r268495 - Print the cpio trailer after every member.

[Sean Silva via llvm-commits]

On Wed, May 4, 2016 at 5:47 AM, Rafael Espindola via llvm-commits <
llvm-commits at lists.llvm.org> wrote:

> Author: rafael
> Date: Wed May  4 07:47:56 2016
> New Revision: 268495
>
> URL: http://llvm.org/viewvc/llvm-project?rev=268495&view=rev
> Log:
> Print the cpio trailer after every member.
>
> This is both simpler and safer. If we crash at any point, there is a
> valid cpio file to reproduce the crash.
>
> Thanks to Rui for the suggestion.
>
> Modified:
>     lld/trunk/ELF/Driver.cpp
>     lld/trunk/ELF/DriverUtils.cpp
>     lld/trunk/ELF/Error.cpp
>     lld/trunk/ELF/Error.h
>
> Modified: lld/trunk/ELF/Driver.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Driver.cpp?rev=268495&r1=268494&r2=268495&view=diff
>
> ==============================================================================
> --- lld/trunk/ELF/Driver.cpp (original)
> +++ lld/trunk/ELF/Driver.cpp Wed May  4 07:47:56 2016
> @@ -493,8 +493,6 @@ template <class ELFT> void LinkerDriver:
>    for (auto *Arg : Args.filtered(OPT_wrap))
>      Symtab.wrap(Arg->getValue());
>
> -  maybeCloseReproArchive();
> -
>    // Write the result to the file.
>    if (Config->GcSections)
>      markLive<ELFT>();
>
> Modified: lld/trunk/ELF/DriverUtils.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/DriverUtils.cpp?rev=268495&r1=268494&r2=268495&view=diff
>
> ==============================================================================
> --- lld/trunk/ELF/DriverUtils.cpp (original)
> +++ lld/trunk/ELF/DriverUtils.cpp Wed May  4 07:47:56 2016
> @@ -117,14 +117,8 @@ static std::string getDestPath(StringRef
>    return Dest.str();
>  }
>
> -static void maybePrintCpioMember(StringRef Path, StringRef Data) {
> -  if (Config->Reproduce.empty())
> -    return;
> -
> -  if (!Driver->IncludedFiles.insert(Path).second)
> -    return;
> -
> -  raw_fd_ostream &OS = *Driver->ReproduceArchive;
> +static void maybePrintCpioMemberAux(raw_fd_ostream &OS, StringRef Path,
> +                                    StringRef Data) {
>    OS << "070707"; // c_magic
>
>    // The c_dev/c_ino pair should be unique according to the spec, but no
> one
> @@ -144,19 +138,28 @@ static void maybePrintCpioMember(StringR
>    OS << Data;                            // c_filedata
>  }
>
> +static void maybePrintCpioMember(StringRef Path, StringRef Data) {
> +  if (Config->Reproduce.empty())
> +    return;
> +
> +  if (!Driver->IncludedFiles.insert(Path).second)
> +    return;
> +  raw_fd_ostream &OS = *Driver->ReproduceArchive;
> +  maybePrintCpioMemberAux(OS, Path, Data);
> +
> +  // Print the trailer and seek back. This way we have a valid archive if
> we
> +  // crash.
> +  uint64_t Pos = OS.tell();
> +  maybePrintCpioMemberAux(OS, "TRAILER!!!", "");
>

Is it 2 or 3 exclamation points? The first source I find
https://www.mkssoftware.com/docs/man4/cpio.4.asp claims the trailer has two
exclamation points. Do you have a specific CPIO spec that you used and
could link?

-- Sean Silva


> +  OS.seek(Pos);
> +}
> +
>  // Write file Src with content Data to the archive.
>  void elf::maybeCopyInputFile(StringRef Src, StringRef Data) {
>    std::string Dest = getDestPath(Src);
>    maybePrintCpioMember(Dest, Data);
>  }
>
> -void elf::maybeCloseReproArchive() {
> -  if (!Driver->ReproduceArchive)
> -    return;
> -  maybePrintCpioMember("TRAILER!!!", "");
> -  Driver->ReproduceArchive.reset();
> -}
> -
>  // Quote a given string if it contains a space character.
>  static std::string quote(StringRef S) {
>    if (S.find(' ') == StringRef::npos)
>
> Modified: lld/trunk/ELF/Error.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Error.cpp?rev=268495&r1=268494&r2=268495&view=diff
>
> ==============================================================================
> --- lld/trunk/ELF/Error.cpp (original)
> +++ lld/trunk/ELF/Error.cpp Wed May  4 07:47:56 2016
> @@ -29,7 +29,6 @@ void warning(const Twine &Msg) { llvm::e
>  void error(const Twine &Msg) {
>    *ErrorOS << Msg << "\n";
>    HasError = true;
> -  maybeCloseReproArchive();
>  }
>
>  void error(std::error_code EC, const Twine &Prefix) {
> @@ -39,7 +38,6 @@ void error(std::error_code EC, const Twi
>
>  void fatal(const Twine &Msg) {
>    llvm::errs() << Msg << "\n";
> -  maybeCloseReproArchive();
>    exit(1);
>  }
>
>
> Modified: lld/trunk/ELF/Error.h
> URL:
> http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Error.h?rev=268495&r1=268494&r2=268495&view=diff
>
> ==============================================================================
> --- lld/trunk/ELF/Error.h (original)
> +++ lld/trunk/ELF/Error.h Wed May  4 07:47:56 2016
> @@ -18,8 +18,6 @@ namespace elf {
>  extern bool HasError;
>  extern llvm::raw_ostream *ErrorOS;
>
> -void maybeCloseReproArchive();
> -
>  void log(const Twine &Msg);
>  void warning(const Twine &Msg);
>
>
>
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