Add a SymbolicFile interface between Binary and ObjectFile.

This interface allows IRObjectFile to be implemented without having dummy
methods for all section and segment related methods.

Both llvm-ar and llvm-nm are changed to use it. Unfortunately the mangler is
still not plugged in since it requires some refactoring to make a Module hold
a DataLayout.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@201881 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Object/SymbolicFile.h

@@ -0,0 +1,190 @@
+//===- SymbolicFile.h - Interface that only provides symbols ----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file declares the SymbolicFile interface.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_OBJECT_SYMBOLIC_FILE_H
+#define LLVM_OBJECT_SYMBOLIC_FILE_H
+
+#include "llvm/Object/Binary.h"
+
+namespace llvm {
+namespace object {
+
+union DataRefImpl {
+  // This entire union should probably be a
+  // char[max(8, sizeof(uintptr_t))] and require the impl to cast.
+  struct {
+    uint32_t a, b;
+  } d;
+  uintptr_t p;
+  DataRefImpl() { std::memset(this, 0, sizeof(DataRefImpl)); }
+};
+
+inline bool operator==(const DataRefImpl &a, const DataRefImpl &b) {
+  // Check bitwise identical. This is the only legal way to compare a union w/o
+  // knowing which member is in use.
+  return std::memcmp(&a, &b, sizeof(DataRefImpl)) == 0;
+}
+
+inline bool operator<(const DataRefImpl &a, const DataRefImpl &b) {
+  // Check bitwise identical. This is the only legal way to compare a union w/o
+  // knowing which member is in use.
+  return std::memcmp(&a, &b, sizeof(DataRefImpl)) < 0;
+}
+
+template <class content_type> class content_iterator {
+  content_type Current;
+
+public:
+  content_iterator(content_type symb) : Current(symb) {}
+
+  const content_type *operator->() const { return &Current; }
+
+  const content_type &operator*() const { return Current; }
+
+  bool operator==(const content_iterator &other) const {
+    return Current == other.Current;
+  }
+
+  bool operator!=(const content_iterator &other) const {
+    return !(*this == other);
+  }
+
+  content_iterator &operator++() { // preincrement
+    Current.moveNext();
+    return *this;
+  }
+};
+
+class SymbolicFile;
+
+/// This is a value type class that represents a single symbol in the list of
+/// symbols in the object file.
+class BasicSymbolRef {
+  DataRefImpl SymbolPimpl;
+  const SymbolicFile *OwningObject;
+
+public:
+  // FIXME: should we add a SF_Text?
+  enum Flags LLVM_ENUM_INT_TYPE(unsigned) {
+    SF_None = 0,
+    SF_Undefined = 1U << 0,      // Symbol is defined in another object file
+    SF_Global = 1U << 1,         // Global symbol
+    SF_Weak = 1U << 2,           // Weak symbol
+    SF_Absolute = 1U << 3,       // Absolute symbol
+    SF_Common = 1U << 4,         // Symbol has common linkage
+    SF_FormatSpecific = 1U << 5  // Specific to the object file format
+                                 // (e.g. section symbols)
+  };
+
+  BasicSymbolRef() : OwningObject(NULL) { }
+  BasicSymbolRef(DataRefImpl SymbolP, const SymbolicFile *Owner);
+
+  bool operator==(const BasicSymbolRef &Other) const;
+  bool operator<(const BasicSymbolRef &Other) const;
+
+  void moveNext();
+
+  error_code printName(raw_ostream &OS) const;
+
+  /// Get symbol flags (bitwise OR of SymbolRef::Flags)
+  uint32_t getFlags() const;
+
+  DataRefImpl getRawDataRefImpl() const;
+  const SymbolicFile *getObject() const;
+};
+
+typedef content_iterator<BasicSymbolRef> basic_symbol_iterator;
+
+const uint64_t UnknownAddressOrSize = ~0ULL;
+
+class SymbolicFile : public Binary {
+public:
+  virtual ~SymbolicFile();
+  SymbolicFile(unsigned int Type, MemoryBuffer *Source, bool BufferOwned);
+
+  // virtual interface.
+  virtual void moveSymbolNext(DataRefImpl &Symb) const = 0;
+
+  virtual error_code printSymbolName(raw_ostream &OS,
+                                     DataRefImpl Symb) const = 0;
+
+  virtual uint32_t getSymbolFlags(DataRefImpl Symb) const = 0;
+
+  virtual basic_symbol_iterator symbol_begin_impl() const = 0;
+
+  virtual basic_symbol_iterator symbol_end_impl() const = 0;
+
+  // convenience wrappers.
+  basic_symbol_iterator symbol_begin() const {
+    return symbol_begin_impl();
+  }
+  basic_symbol_iterator symbol_end() const {
+    return symbol_end_impl();
+  }
+
+  // construction aux.
+  static ErrorOr<SymbolicFile *> createIRObjectFile(MemoryBuffer *Object,
+                                                    LLVMContext &Context,
+                                                    bool BufferOwned = true);
+
+  static ErrorOr<SymbolicFile *> createSymbolicFile(MemoryBuffer *Object,
+                                                    bool BufferOwned,
+                                                    sys::fs::file_magic Type,
+                                                    LLVMContext *Context);
+
+  static ErrorOr<SymbolicFile *> createSymbolicFile(MemoryBuffer *Object) {
+    return createSymbolicFile(Object, true, sys::fs::file_magic::unknown, 0);
+  }
+  static ErrorOr<SymbolicFile *> createSymbolicFile(StringRef ObjectPath);
+
+  static inline bool classof(const Binary *v) {
+    return v->isSymbolic();
+  }
+};
+
+inline BasicSymbolRef::BasicSymbolRef(DataRefImpl SymbolP,
+                                      const SymbolicFile *Owner)
+    : SymbolPimpl(SymbolP), OwningObject(Owner) {}
+
+inline bool BasicSymbolRef::operator==(const BasicSymbolRef &Other) const {
+  return SymbolPimpl == Other.SymbolPimpl;
+}
+
+inline bool BasicSymbolRef::operator<(const BasicSymbolRef &Other) const {
+  return SymbolPimpl < Other.SymbolPimpl;
+}
+
+inline void BasicSymbolRef::moveNext() {
+  return OwningObject->moveSymbolNext(SymbolPimpl);
+}
+
+inline error_code BasicSymbolRef::printName(raw_ostream &OS) const {
+  return OwningObject->printSymbolName(OS, SymbolPimpl);
+}
+
+inline uint32_t BasicSymbolRef::getFlags() const {
+  return OwningObject->getSymbolFlags(SymbolPimpl);
+}
+
+inline DataRefImpl BasicSymbolRef::getRawDataRefImpl() const {
+  return SymbolPimpl;
+}
+
+inline const SymbolicFile *BasicSymbolRef::getObject() const {
+  return OwningObject;
+}
+
+}
+}
+
+#endif