11 files changed, 533 insertions, 0 deletions
diff --git a/include/lld/Common/Args.h b/include/lld/Common/Args.h
new file mode 100644
index 0000000000000..c49a6a7e17e75
--- /dev/null
+++ b/include/lld/Common/Args.h
@@ -0,0 +1,35 @@
+//===- Args.h ---------------------------------------------------*- C++ -*-===//
+//
+//                             The LLVM Linker
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLD_ARGS_H
+#define LLD_ARGS_H
+
+#include "lld/Common/LLVM.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include <vector>
+
+namespace llvm {
+namespace opt {
+class InputArgList;
+}
+} // namespace llvm
+
+namespace lld {
+namespace args {
+int getInteger(llvm::opt::InputArgList &Args, unsigned Key, int Default);
+std::vector<StringRef> getStrings(llvm::opt::InputArgList &Args, int Id);
+
+uint64_t getZOptionValue(llvm::opt::InputArgList &Args, int Id, StringRef Key,
+                         uint64_t Default);
+
+std::vector<StringRef> getLines(MemoryBufferRef MB);
+} // namespace args
+} // namespace lld
+
+#endif
diff --git a/include/lld/Common/Driver.h b/include/lld/Common/Driver.h
new file mode 100644
index 0000000000000..15ec3cd44cb55
--- /dev/null
+++ b/include/lld/Common/Driver.h
@@ -0,0 +1,43 @@
+//===- lld/Common/Driver.h - Linker Driver Emulator -----------------------===//
+//
+//                             The LLVM Linker
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLD_COMMON_DRIVER_H
+#define LLD_COMMON_DRIVER_H
+
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/Support/raw_ostream.h"
+
+namespace lld {
+namespace coff {
+bool link(llvm::ArrayRef<const char *> Args, bool CanExitEarly,
+          llvm::raw_ostream &Diag = llvm::errs());
+}
+
+namespace mingw {
+bool link(llvm::ArrayRef<const char *> Args,
+          llvm::raw_ostream &Diag = llvm::errs());
+}
+
+namespace elf {
+bool link(llvm::ArrayRef<const char *> Args, bool CanExitEarly,
+          llvm::raw_ostream &Diag = llvm::errs());
+}
+
+namespace mach_o {
+bool link(llvm::ArrayRef<const char *> Args,
+          llvm::raw_ostream &Diag = llvm::errs());
+}
+
+namespace wasm {
+bool link(llvm::ArrayRef<const char *> Args, bool CanExitEarly,
+          llvm::raw_ostream &Diag = llvm::errs());
+}
+}
+
+#endif
diff --git a/include/lld/Common/ErrorHandler.h b/include/lld/Common/ErrorHandler.h
new file mode 100644
index 0000000000000..8ae6f46ac59e1
--- /dev/null
+++ b/include/lld/Common/ErrorHandler.h
@@ -0,0 +1,112 @@
+//===- ErrorHandler.h -------------------------------------------*- C++ -*-===//
+//
+//                             The LLVM Linker
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// In LLD, we have three levels of errors: fatal, error or warn.
+//
+// Fatal makes the program exit immediately with an error message.
+// You shouldn't use it except for reporting a corrupted input file.
+//
+// Error prints out an error message and increment a global variable
+// ErrorCount to record the fact that we met an error condition. It does
+// not exit, so it is safe for a lld-as-a-library use case. It is generally
+// useful because it can report more than one error in a single run.
+//
+// Warn doesn't do anything but printing out a given message.
+//
+// It is not recommended to use llvm::outs() or llvm::errs() directly
+// in LLD because they are not thread-safe. The functions declared in
+// this file are mutually excluded, so you want to use them instead.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLD_COMMON_ERRORHANDLER_H
+#define LLD_COMMON_ERRORHANDLER_H
+
+#include "lld/Common/LLVM.h"
+
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/FileOutputBuffer.h"
+
+namespace lld {
+
+class ErrorHandler {
+public:
+  uint64_t ErrorCount = 0;
+  uint64_t ErrorLimit = 20;
+  StringRef ErrorLimitExceededMsg = "too many errors emitted, stopping now";
+  StringRef LogName = "lld";
+  llvm::raw_ostream *ErrorOS = &llvm::errs();
+  bool ColorDiagnostics = llvm::errs().has_colors();
+  bool ExitEarly = true;
+  bool FatalWarnings = false;
+  bool Verbose = false;
+
+  void error(const Twine &Msg);
+  LLVM_ATTRIBUTE_NORETURN void fatal(const Twine &Msg);
+  void log(const Twine &Msg);
+  void message(const Twine &Msg);
+  void warn(const Twine &Msg);
+
+  std::unique_ptr<llvm::FileOutputBuffer> OutputBuffer;
+
+private:
+  void print(StringRef S, raw_ostream::Colors C);
+};
+
+/// Returns the default error handler.
+ErrorHandler &errorHandler();
+
+inline void error(const Twine &Msg) { errorHandler().error(Msg); }
+inline LLVM_ATTRIBUTE_NORETURN void fatal(const Twine &Msg) {
+  errorHandler().fatal(Msg);
+}
+inline void log(const Twine &Msg) { errorHandler().log(Msg); }
+inline void message(const Twine &Msg) { errorHandler().message(Msg); }
+inline void warn(const Twine &Msg) { errorHandler().warn(Msg); }
+inline uint64_t errorCount() { return errorHandler().ErrorCount; }
+
+LLVM_ATTRIBUTE_NORETURN void exitLld(int Val);
+
+// check functions are convenient functions to strip errors
+// from error-or-value objects.
+template <class T> T check(ErrorOr<T> E) {
+  if (auto EC = E.getError())
+    fatal(EC.message());
+  return std::move(*E);
+}
+
+template <class T> T check(Expected<T> E) {
+  if (!E)
+    fatal(llvm::toString(E.takeError()));
+  return std::move(*E);
+}
+
+template <class T>
+T check2(ErrorOr<T> E, llvm::function_ref<std::string()> Prefix) {
+  if (auto EC = E.getError())
+    fatal(Prefix() + ": " + EC.message());
+  return std::move(*E);
+}
+
+template <class T>
+T check2(Expected<T> E, llvm::function_ref<std::string()> Prefix) {
+  if (!E)
+    fatal(Prefix() + ": " + toString(E.takeError()));
+  return std::move(*E);
+}
+
+inline std::string toString(const Twine &S) { return S.str(); }
+
+// To evaluate the second argument lazily, we use C macro.
+#define CHECK(E, S) check2(E, [&] { return toString(S); })
+
+} // namespace lld
+
+#endif
diff --git a/include/lld/Common/LLVM.h b/include/lld/Common/LLVM.h
new file mode 100644
index 0000000000000..b5d0e2bffb038
--- /dev/null
+++ b/include/lld/Common/LLVM.h
@@ -0,0 +1,83 @@
+//===--- LLVM.h - Import various common LLVM datatypes ----------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file forward declares and imports various common LLVM datatypes that
+// lld wants to use unqualified.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLD_COMMON_LLVM_H
+#define LLD_COMMON_LLVM_H
+
+// This should be the only #include, force #includes of all the others on
+// clients.
+#include "llvm/ADT/Hashing.h"
+#include "llvm/Support/Casting.h"
+#include <utility>
+
+namespace llvm {
+  // ADT's.
+  class Error;
+  class StringRef;
+  class Twine;
+  class MemoryBuffer;
+  class MemoryBufferRef;
+  template<typename T> class ArrayRef;
+  template<unsigned InternalLen> class SmallString;
+  template<typename T, unsigned N> class SmallVector;
+  template<typename T> class SmallVectorImpl;
+
+  template<typename T>
+  struct SaveAndRestore;
+
+  template<typename T>
+  class ErrorOr;
+
+  template<typename T>
+  class Expected;
+
+  class raw_ostream;
+  // TODO: DenseMap, ...
+}
+
+namespace lld {
+  // Casting operators.
+  using llvm::isa;
+  using llvm::cast;
+  using llvm::dyn_cast;
+  using llvm::dyn_cast_or_null;
+  using llvm::cast_or_null;
+
+  // ADT's.
+  using llvm::Error;
+  using llvm::StringRef;
+  using llvm::Twine;
+  using llvm::MemoryBuffer;
+  using llvm::MemoryBufferRef;
+  using llvm::ArrayRef;
+  using llvm::SmallString;
+  using llvm::SmallVector;
+  using llvm::SmallVectorImpl;
+  using llvm::SaveAndRestore;
+  using llvm::ErrorOr;
+  using llvm::Expected;
+
+  using llvm::raw_ostream;
+} // end namespace lld.
+
+namespace std {
+template <> struct hash<llvm::StringRef> {
+public:
+  size_t operator()(const llvm::StringRef &s) const {
+    return llvm::hash_value(s);
+  }
+};
+}
+
+#endif
diff --git a/include/lld/Common/Memory.h b/include/lld/Common/Memory.h
new file mode 100644
index 0000000000000..699f7c1654cd3
--- /dev/null
+++ b/include/lld/Common/Memory.h
@@ -0,0 +1,60 @@
+//===- Memory.h -------------------------------------------------*- C++ -*-===//
+//
+//                             The LLVM Linker
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines arena allocators.
+//
+// Almost all large objects, such as files, sections or symbols, are
+// used for the entire lifetime of the linker once they are created.
+// This usage characteristic makes arena allocator an attractive choice
+// where the entire linker is one arena. With an arena, newly created
+// objects belong to the arena and freed all at once when everything is done.
+// Arena allocators are efficient and easy to understand.
+// Most objects are allocated using the arena allocators defined by this file.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLD_COMMON_MEMORY_H
+#define LLD_COMMON_MEMORY_H
+
+#include "llvm/Support/Allocator.h"
+#include "llvm/Support/StringSaver.h"
+#include <vector>
+
+namespace lld {
+
+// Use this arena if your object doesn't have a destructor.
+extern llvm::BumpPtrAllocator BAlloc;
+extern llvm::StringSaver Saver;
+
+void freeArena();
+
+// These two classes are hack to keep track of all
+// SpecificBumpPtrAllocator instances.
+struct SpecificAllocBase {
+  SpecificAllocBase() { Instances.push_back(this); }
+  virtual ~SpecificAllocBase() = default;
+  virtual void reset() = 0;
+  static std::vector<SpecificAllocBase *> Instances;
+};
+
+template <class T> struct SpecificAlloc : public SpecificAllocBase {
+  void reset() override { Alloc.DestroyAll(); }
+  llvm::SpecificBumpPtrAllocator<T> Alloc;
+};
+
+// Use this arena if your object has a destructor.
+// Your destructor will be invoked from freeArena().
+template <typename T, typename... U> T *make(U &&... Args) {
+  static SpecificAlloc<T> Alloc;
+  return new (Alloc.Alloc.Allocate()) T(std::forward<U>(Args)...);
+}
+
+} // namespace lld
+
+#endif
diff --git a/include/lld/Common/Reproduce.h b/include/lld/Common/Reproduce.h
new file mode 100644
index 0000000000000..0f425de269c7f
--- /dev/null
+++ b/include/lld/Common/Reproduce.h
@@ -0,0 +1,39 @@
+//===- Reproduce.h - Utilities for creating reproducers ---------*- C++ -*-===//
+//
+//                             The LLVM Linker
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLD_COMMON_REPRODUCE_H
+#define LLD_COMMON_REPRODUCE_H
+
+#include "lld/Common/LLVM.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Error.h"
+
+namespace llvm {
+namespace opt { class Arg; }
+}
+
+namespace lld {
+
+// Makes a given pathname an absolute path first, and then remove
+// beginning /. For example, "../foo.o" is converted to "home/john/foo.o",
+// assuming that the current directory is "/home/john/bar".
+std::string relativeToRoot(StringRef Path);
+
+// Quote a given string if it contains a space character.
+std::string quote(StringRef S);
+
+// Rewrite the given path if a file exists with that pathname, otherwise
+// returns the original path.
+std::string rewritePath(StringRef S);
+
+// Returns the string form of the given argument.
+std::string toString(const llvm::opt::Arg &Arg);
+}
+
+#endif
diff --git a/include/lld/Common/Strings.h b/include/lld/Common/Strings.h
new file mode 100644
index 0000000000000..1a63f75f9ecfe
--- /dev/null
+++ b/include/lld/Common/Strings.h
@@ -0,0 +1,23 @@
+//===- Strings.h ------------------------------------------------*- C++ -*-===//
+//
+//                             The LLVM Linker
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLD_STRINGS_H
+#define LLD_STRINGS_H
+
+#include "llvm/ADT/Optional.h"
+#include "llvm/ADT/StringRef.h"
+#include <string>
+
+namespace lld {
+// Returns a demangled C++ symbol name. If Name is not a mangled
+// name, it returns Optional::None.
+llvm::Optional<std::string> demangleItanium(llvm::StringRef Name);
+}
+
+#endif
diff --git a/include/lld/Common/TargetOptionsCommandFlags.h b/include/lld/Common/TargetOptionsCommandFlags.h
new file mode 100644
index 0000000000000..9c4ff7cea3fb8
--- /dev/null
+++ b/include/lld/Common/TargetOptionsCommandFlags.h
@@ -0,0 +1,21 @@
+//===-- TargetOptionsCommandFlags.h ----------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Helper to create TargetOptions from command line flags.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/Optional.h"
+#include "llvm/Support/CodeGen.h"
+#include "llvm/Target/TargetOptions.h"
+
+namespace lld {
+llvm::TargetOptions InitTargetOptionsFromCodeGenFlags();
+llvm::Optional<llvm::CodeModel::Model> GetCodeModelFromCMModel();
+}
diff --git a/include/lld/Common/Threads.h b/include/lld/Common/Threads.h
new file mode 100644
index 0000000000000..8545907531433
--- /dev/null
+++ b/include/lld/Common/Threads.h
@@ -0,0 +1,86 @@
+//===- Threads.h ------------------------------------------------*- C++ -*-===//
+//
+//                             The LLVM Linker
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// LLD supports threads to distribute workloads to multiple cores. Using
+// multicore is most effective when more than one core are idle. At the
+// last step of a build, it is often the case that a linker is the only
+// active process on a computer. So, we are naturally interested in using
+// threads wisely to reduce latency to deliver results to users.
+//
+// That said, we don't want to do "too clever" things using threads.
+// Complex multi-threaded algorithms are sometimes extremely hard to
+// reason about and can easily mess up the entire design.
+//
+// Fortunately, when a linker links large programs (when the link time is
+// most critical), it spends most of the time to work on massive number of
+// small pieces of data of the same kind, and there are opportunities for
+// large parallelism there. Here are examples:
+//
+//  - We have hundreds of thousands of input sections that need to be
+//    copied to a result file at the last step of link. Once we fix a file
+//    layout, each section can be copied to its destination and its
+//    relocations can be applied independently.
+//
+//  - We have tens of millions of small strings when constructing a
+//    mergeable string section.
+//
+// For the cases such as the former, we can just use parallelForEach
+// instead of std::for_each (or a plain for loop). Because tasks are
+// completely independent from each other, we can run them in parallel
+// without any coordination between them. That's very easy to understand
+// and reason about.
+//
+// For the cases such as the latter, we can use parallel algorithms to
+// deal with massive data. We have to write code for a tailored algorithm
+// for each problem, but the complexity of multi-threading is isolated in
+// a single pass and doesn't affect the linker's overall design.
+//
+// The above approach seems to be working fairly well. As an example, when
+// linking Chromium (output size 1.6 GB), using 4 cores reduces latency to
+// 75% compared to single core (from 12.66 seconds to 9.55 seconds) on my
+// Ivy Bridge Xeon 2.8 GHz machine. Using 40 cores reduces it to 63% (from
+// 12.66 seconds to 7.95 seconds). Because of the Amdahl's law, the
+// speedup is not linear, but as you add more cores, it gets faster.
+//
+// On a final note, if you are trying to optimize, keep the axiom "don't
+// guess, measure!" in mind. Some important passes of the linker are not
+// that slow. For example, resolving all symbols is not a very heavy pass,
+// although it would be very hard to parallelize it. You want to first
+// identify a slow pass and then optimize it.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLD_COMMON_THREADS_H
+#define LLD_COMMON_THREADS_H
+
+#include "llvm/Support/Parallel.h"
+#include <functional>
+
+namespace lld {
+
+extern bool ThreadsEnabled;
+
+template <typename R, class FuncTy> void parallelForEach(R &&Range, FuncTy Fn) {
+  if (ThreadsEnabled)
+    for_each(llvm::parallel::par, std::begin(Range), std::end(Range), Fn);
+  else
+    for_each(llvm::parallel::seq, std::begin(Range), std::end(Range), Fn);
+}
+
+inline void parallelForEachN(size_t Begin, size_t End,
+                             std::function<void(size_t)> Fn) {
+  if (ThreadsEnabled)
+    for_each_n(llvm::parallel::par, Begin, End, Fn);
+  else
+    for_each_n(llvm::parallel::seq, Begin, End, Fn);
+}
+
+} // namespace lld
+
+#endif
diff --git a/include/lld/Common/Version.h b/include/lld/Common/Version.h
new file mode 100644
index 0000000000000..93de77df5804e
--- /dev/null
+++ b/include/lld/Common/Version.h
@@ -0,0 +1,25 @@
+//===- lld/Common/Version.h - LLD Version Number ----------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Defines a version-related utility function.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLD_VERSION_H
+#define LLD_VERSION_H
+
+#include "lld/Common/Version.inc"
+#include "llvm/ADT/StringRef.h"
+
+namespace lld {
+/// \brief Retrieves a string representing the complete lld version.
+std::string getLLDVersion();
+}
+
+#endif // LLD_VERSION_H
diff --git a/include/lld/Common/Version.inc.in b/include/lld/Common/Version.inc.in
new file mode 100644
index 0000000000000..2789a5c460892
--- /dev/null
+++ b/include/lld/Common/Version.inc.in
@@ -0,0 +1,6 @@
+#define LLD_VERSION @LLD_VERSION@
+#define LLD_VERSION_STRING "@LLD_VERSION@"
+#define LLD_VERSION_MAJOR @LLD_VERSION_MAJOR@
+#define LLD_VERSION_MINOR @LLD_VERSION_MINOR@
+#define LLD_REVISION_STRING "@LLD_REVISION@"
+#define LLD_REPOSITORY_STRING "@LLD_REPOSITORY@"