vendor/llvm/llvm-trunk-r321017

1 files changed, 325 insertions, 0 deletions

diff --git a/tools/llvm-objcopy/llvm-objcopy.cpp b/tools/llvm-objcopy/llvm-objcopy.cpp
new file mode 100644
index 000000000000..9d60ae426390
--- /dev/null
+++ b/tools/llvm-objcopy/llvm-objcopy.cpp
@@ -0,0 +1,325 @@
+//===- llvm-objcopy.cpp ---------------------------------------------------===//
+//
+//                      The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm-objcopy.h"
+#include "Object.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/Twine.h"
+#include "llvm/BinaryFormat/ELF.h"
+#include "llvm/Object/Binary.h"
+#include "llvm/Object/ELFObjectFile.h"
+#include "llvm/Object/ELFTypes.h"
+#include "llvm/Object/Error.h"
+#include "llvm/Support/Casting.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/ErrorOr.h"
+#include "llvm/Support/FileOutputBuffer.h"
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/PrettyStackTrace.h"
+#include "llvm/Support/Signals.h"
+#include "llvm/Support/raw_ostream.h"
+#include <algorithm>
+#include <cassert>
+#include <cstdlib>
+#include <functional>
+#include <iterator>
+#include <memory>
+#include <string>
+#include <system_error>
+#include <utility>
+
+using namespace llvm;
+using namespace object;
+using namespace ELF;
+
+// The name this program was invoked as.
+static StringRef ToolName;
+
+namespace llvm {
+
+LLVM_ATTRIBUTE_NORETURN void error(Twine Message) {
+  errs() << ToolName << ": " << Message << ".\n";
+  errs().flush();
+  exit(1);
+}
+
+LLVM_ATTRIBUTE_NORETURN void reportError(StringRef File, std::error_code EC) {
+  assert(EC);
+  errs() << ToolName << ": '" << File << "': " << EC.message() << ".\n";
+  exit(1);
+}
+
+LLVM_ATTRIBUTE_NORETURN void reportError(StringRef File, Error E) {
+  assert(E);
+  std::string Buf;
+  raw_string_ostream OS(Buf);
+  logAllUnhandledErrors(std::move(E), OS, "");
+  OS.flush();
+  errs() << ToolName << ": '" << File << "': " << Buf;
+  exit(1);
+}
+
+} // end namespace llvm
+
+static cl::opt<std::string> InputFilename(cl::Positional, cl::desc("<input>"));
+static cl::opt<std::string> OutputFilename(cl::Positional, cl::desc("<output>"),
+                                           cl::init("-"));
+static cl::opt<std::string>
+    OutputFormat("O", cl::desc("Set output format to one of the following:"
+                               "\n\tbinary"));
+static cl::list<std::string> ToRemove("remove-section",
+                                      cl::desc("Remove <section>"),
+                                      cl::value_desc("section"));
+static cl::alias ToRemoveA("R", cl::desc("Alias for remove-section"),
+                           cl::aliasopt(ToRemove));
+static cl::opt<bool> StripAll(
+    "strip-all",
+    cl::desc(
+        "Removes non-allocated sections other than .gnu.warning* sections"));
+static cl::opt<bool>
+    StripAllGNU("strip-all-gnu",
+                cl::desc("Removes symbol, relocation, and debug information"));
+static cl::list<std::string> Keep("keep", cl::desc("Keep <section>"),
+                                  cl::value_desc("section"));
+static cl::list<std::string> OnlyKeep("only-keep",
+                                      cl::desc("Remove all but <section>"),
+                                      cl::value_desc("section"));
+static cl::alias OnlyKeepA("j", cl::desc("Alias for only-keep"),
+                           cl::aliasopt(OnlyKeep));
+static cl::opt<bool> StripDebug("strip-debug",
+                                cl::desc("Removes all debug information"));
+static cl::opt<bool> StripSections("strip-sections",
+                                   cl::desc("Remove all section headers"));
+static cl::opt<bool>
+    StripNonAlloc("strip-non-alloc",
+                  cl::desc("Remove all non-allocated sections"));
+static cl::opt<bool>
+    StripDWO("strip-dwo", cl::desc("Remove all DWARF .dwo sections from file"));
+static cl::opt<bool> ExtractDWO(
+    "extract-dwo",
+    cl::desc("Remove all sections that are not DWARF .dwo sections from file"));
+static cl::opt<std::string>
+    SplitDWO("split-dwo",
+             cl::desc("Equivalent to extract-dwo on the input file to "
+                      "<dwo-file>, then strip-dwo on the input file"),
+             cl::value_desc("dwo-file"));
+
+using SectionPred = std::function<bool(const SectionBase &Sec)>;
+
+bool IsDWOSection(const SectionBase &Sec) { return Sec.Name.endswith(".dwo"); }
+
+template <class ELFT>
+bool OnlyKeepDWOPred(const Object<ELFT> &Obj, const SectionBase &Sec) {
+  // We can't remove the section header string table.
+  if (&Sec == Obj.getSectionHeaderStrTab())
+    return false;
+  // Short of keeping the string table we want to keep everything that is a DWO
+  // section and remove everything else.
+  return !IsDWOSection(Sec);
+}
+
+template <class ELFT>
+void WriteObjectFile(const Object<ELFT> &Obj, StringRef File) {
+  std::unique_ptr<FileOutputBuffer> Buffer;
+  Expected<std::unique_ptr<FileOutputBuffer>> BufferOrErr =
+      FileOutputBuffer::create(File, Obj.totalSize(),
+                               FileOutputBuffer::F_executable);
+  handleAllErrors(BufferOrErr.takeError(), [](const ErrorInfoBase &) {
+    error("failed to open " + OutputFilename);
+  });
+  Buffer = std::move(*BufferOrErr);
+
+  Obj.write(*Buffer);
+  if (auto E = Buffer->commit())
+    reportError(File, errorToErrorCode(std::move(E)));
+}
+
+template <class ELFT>
+void SplitDWOToFile(const ELFObjectFile<ELFT> &ObjFile, StringRef File) {
+  // Construct a second output file for the DWO sections.
+  ELFObject<ELFT> DWOFile(ObjFile);
+
+  DWOFile.removeSections([&](const SectionBase &Sec) {
+    return OnlyKeepDWOPred<ELFT>(DWOFile, Sec);
+  });
+  DWOFile.finalize();
+  WriteObjectFile(DWOFile, File);
+}
+
+// This function handles the high level operations of GNU objcopy including
+// handling command line options. It's important to outline certain properties
+// we expect to hold of the command line operations. Any operation that "keeps"
+// should keep regardless of a remove. Additionally any removal should respect
+// any previous removals. Lastly whether or not something is removed shouldn't
+// depend a) on the order the options occur in or b) on some opaque priority
+// system. The only priority is that keeps/copies overrule removes.
+template <class ELFT> void CopyBinary(const ELFObjectFile<ELFT> &ObjFile) {
+  std::unique_ptr<Object<ELFT>> Obj;
+
+  if (!OutputFormat.empty() && OutputFormat != "binary")
+    error("invalid output format '" + OutputFormat + "'");
+  if (!OutputFormat.empty() && OutputFormat == "binary")
+    Obj = llvm::make_unique<BinaryObject<ELFT>>(ObjFile);
+  else
+    Obj = llvm::make_unique<ELFObject<ELFT>>(ObjFile);
+
+  if (!SplitDWO.empty())
+    SplitDWOToFile<ELFT>(ObjFile, SplitDWO.getValue()); 
+
+  SectionPred RemovePred = [](const SectionBase &) { return false; };
+
+  // Removes:
+
+  if (!ToRemove.empty()) {
+    RemovePred = [&](const SectionBase &Sec) {
+      return std::find(std::begin(ToRemove), std::end(ToRemove), Sec.Name) !=
+             std::end(ToRemove);
+    };
+  }
+
+  if (StripDWO || !SplitDWO.empty())
+    RemovePred = [RemovePred](const SectionBase &Sec) {
+      return IsDWOSection(Sec) || RemovePred(Sec);
+    };
+
+  if (ExtractDWO)
+    RemovePred = [RemovePred, &Obj](const SectionBase &Sec) {
+      return OnlyKeepDWOPred(*Obj, Sec) || RemovePred(Sec);
+    };
+
+  if (StripAllGNU)
+    RemovePred = [RemovePred, &Obj](const SectionBase &Sec) {
+      if (RemovePred(Sec))
+        return true;
+      if ((Sec.Flags & SHF_ALLOC) != 0)
+        return false;
+      if (&Sec == Obj->getSectionHeaderStrTab())
+        return false;
+      switch (Sec.Type) {
+      case SHT_SYMTAB:
+      case SHT_REL:
+      case SHT_RELA:
+      case SHT_STRTAB:
+        return true;
+      }
+      return Sec.Name.startswith(".debug");
+    };
+
+  if (StripSections) {
+    RemovePred = [RemovePred](const SectionBase &Sec) {
+      return RemovePred(Sec) || (Sec.Flags & SHF_ALLOC) == 0;
+    };
+    Obj->WriteSectionHeaders = false;
+  }
+
+  if (StripDebug) {
+    RemovePred = [RemovePred](const SectionBase &Sec) {
+      return RemovePred(Sec) || Sec.Name.startswith(".debug");
+    };
+  }
+
+  if (StripNonAlloc)
+    RemovePred = [RemovePred, &Obj](const SectionBase &Sec) {
+      if (RemovePred(Sec))
+        return true;
+      if (&Sec == Obj->getSectionHeaderStrTab())
+        return false;
+      return (Sec.Flags & SHF_ALLOC) == 0;
+    };
+
+  if (StripAll)
+    RemovePred = [RemovePred, &Obj](const SectionBase &Sec) {
+      if (RemovePred(Sec))
+        return true;
+      if (&Sec == Obj->getSectionHeaderStrTab())
+        return false;
+      if (Sec.Name.startswith(".gnu.warning"))
+        return false;
+      return (Sec.Flags & SHF_ALLOC) == 0;
+    };
+
+  // Explicit copies:
+
+  if (!OnlyKeep.empty()) {
+    RemovePred = [RemovePred, &Obj](const SectionBase &Sec) {
+      // Explicitly keep these sections regardless of previous removes.
+      if (std::find(std::begin(OnlyKeep), std::end(OnlyKeep), Sec.Name) !=
+          std::end(OnlyKeep))
+        return false;
+
+      // Allow all implicit removes.
+      if (RemovePred(Sec)) {
+        return true;
+      }
+
+      // Keep special sections.
+      if (Obj->getSectionHeaderStrTab() == &Sec) {
+        return false;
+      }
+      if (Obj->getSymTab() == &Sec || Obj->getSymTab()->getStrTab() == &Sec) {
+        return false;
+      }
+      // Remove everything else.
+      return true;
+    };
+  }
+
+  if (!Keep.empty()) {
+    RemovePred = [RemovePred](const SectionBase &Sec) {
+      // Explicitly keep these sections regardless of previous removes.
+      if (std::find(std::begin(Keep), std::end(Keep), Sec.Name) !=
+          std::end(Keep))
+        return false;
+      // Otherwise defer to RemovePred.
+      return RemovePred(Sec);
+    };
+  }
+
+  Obj->removeSections(RemovePred);
+  Obj->finalize();
+  WriteObjectFile(*Obj, OutputFilename.getValue());
+}
+
+int main(int argc, char **argv) {
+  // Print a stack trace if we signal out.
+  sys::PrintStackTraceOnErrorSignal(argv[0]);
+  PrettyStackTraceProgram X(argc, argv);
+  llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
+  cl::ParseCommandLineOptions(argc, argv, "llvm objcopy utility\n");
+  ToolName = argv[0];
+  if (InputFilename.empty()) {
+    cl::PrintHelpMessage();
+    return 2;
+  }
+  Expected<OwningBinary<Binary>> BinaryOrErr = createBinary(InputFilename);
+  if (!BinaryOrErr)
+    reportError(InputFilename, BinaryOrErr.takeError());
+  Binary &Binary = *BinaryOrErr.get().getBinary();
+  if (auto *o = dyn_cast<ELFObjectFile<ELF64LE>>(&Binary)) {
+    CopyBinary(*o);
+    return 0;
+  }
+  if (auto *o = dyn_cast<ELFObjectFile<ELF32LE>>(&Binary)) {
+    CopyBinary(*o);
+    return 0;
+  }
+  if (auto *o = dyn_cast<ELFObjectFile<ELF64BE>>(&Binary)) {
+    CopyBinary(*o);
+    return 0;
+  }
+  if (auto *o = dyn_cast<ELFObjectFile<ELF32BE>>(&Binary)) {
+    CopyBinary(*o);
+    return 0;
+  }
+  reportError(InputFilename, object_error::invalid_file_type);
+}