Sketch out a DWARF parser.

This introduces a new library to LLVM: libDebugInfo. It will provide debug information
parsing to LLVM. Much of the design and some of the code is taken from the LLDB project.

It also contains an llvm-dwarfdump tool that can dump the abbrevs and DIEs from an
object file. It can be used to write tests for DWARF input and output easily.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139627 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/DebugInfo/DIContext.h

@@ -0,0 +1,42 @@
+//===-- DIContext.h ---------------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines DIContext, and abstract data structure that holds
+// debug information data.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_DEBUGINFO_DICONTEXT_H
+#define LLVM_DEBUGINFO_DICONTEXT_H
+
+#include "llvm/ADT/StringRef.h"
+#include "llvm/DebugInfo/DILineInfo.h"
+
+namespace llvm {
+
+class raw_ostream;
+
+class DIContext {
+public:
+  virtual ~DIContext();
+
+  /// getDWARFContext - get a context for binary DWARF data.
+  static DIContext *getDWARFContext(bool isLittleEndian,
+                                    StringRef infoSection,
+                                    StringRef abbrevSection,
+                                    StringRef aRangeSection = StringRef(),
+                                    StringRef lineSection = StringRef(),
+                                    StringRef stringSection = StringRef());
+
+  virtual void dump(raw_ostream &OS) = 0;
+};
+
+}
+
+#endif

lib/CMakeLists.txt

@@ -9,6 +9,7 @@ add_subdirectory(Analysis)
 add_subdirectory(MC)
 add_subdirectory(CompilerDriver)
 add_subdirectory(Object)
+add_subdirectory(DebugInfo)
 add_subdirectory(ExecutionEngine)
 add_subdirectory(Target)
 add_subdirectory(AsmParser)

lib/DebugInfo/CMakeLists.txt

@@ -0,0 +1,13 @@
+add_llvm_library(LLVMMC
+  DIContext.cpp
+  DWARFAbbreviationDeclaration.cpp
+  DWARFCompileUnit.cpp
+  DWARFContext.cpp
+  DWARFDebugAbbrev.cpp
+  DWARFDebugInfoEntry.cpp
+  DWARFFormValue.cpp
+  )
+
+add_llvm_library_dependencies(LLVMDebugInfo
+  LLVMSupport
+  )

lib/DebugInfo/DIContext.cpp

@@ -0,0 +1,24 @@
+//===-- DIContext.cpp -----------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/DebugInfo/DIContext.h"
+#include "DWARFContext.h"
+using namespace llvm;
+
+DIContext::~DIContext() {}
+
+DIContext *DIContext::getDWARFContext(bool isLittleEndian,
+                                      StringRef infoSection,
+                                      StringRef abbrevSection,
+                                      StringRef aRangeSection,
+                                      StringRef lineSection,
+                                      StringRef stringSection) {
+  return new DWARFContextInMemory(isLittleEndian, infoSection, abbrevSection,
+                                  aRangeSection, lineSection, stringSection);
+}

lib/DebugInfo/DWARFAbbreviationDeclaration.cpp

@@ -0,0 +1,66 @@
+//===-- DWARFAbbreviationDeclaration.cpp ----------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "DWARFAbbreviationDeclaration.h"
+#include "llvm/Support/Dwarf.h"
+#include "llvm/Support/raw_ostream.h"
+using namespace llvm;
+using namespace dwarf;
+
+bool
+DWARFAbbreviationDeclaration::extract(DataExtractor data, uint32_t* offset_ptr){
+  return extract(data, offset_ptr, data.getULEB128(offset_ptr));
+}
+
+bool
+DWARFAbbreviationDeclaration::extract(DataExtractor data, uint32_t* offset_ptr,
+                                      uint32_t code) {
+  Code = code;
+  Attributes.clear();
+  if (Code) {
+    Tag = data.getULEB128(offset_ptr);
+    HasChildren = data.getU8(offset_ptr);
+
+    while (data.isValidOffset(*offset_ptr)) {
+      uint16_t attr = data.getULEB128(offset_ptr);
+      uint16_t form = data.getULEB128(offset_ptr);
+
+      if (attr && form)
+        Attributes.push_back(DWARFAttribute(attr, form));
+      else
+        break;
+    }
+
+    return Tag != 0;
+  }
+  else {
+    Tag = 0;
+    HasChildren = false;
+  }
+
+  return false;
+}
+
+void DWARFAbbreviationDeclaration::dump(raw_ostream &OS) const {
+  OS << '[' << getCode() << "] " << TagString(getTag()) << "\tDW_CHILDREN_"
+     << (hasChildren() ? "yes" : "no") << '\n';
+  for (unsigned i = 0, e = Attributes.size(); i != e; ++i)
+    OS << '\t' << AttributeString(Attributes[i].getAttribute())
+       << '\t' << FormEncodingString(Attributes[i].getForm()) << '\n';
+  OS << '\n';
+}
+
+uint32_t
+DWARFAbbreviationDeclaration::findAttributeIndex(uint16_t attr) const {
+  for (uint32_t i = 0, e = Attributes.size(); i != e; ++i) {
+    if (Attributes[i].getAttribute() == attr)
+      return i;
+  }
+  return -1U;
+}

lib/DebugInfo/DWARFAbbreviationDeclaration.h

@@ -0,0 +1,54 @@
+//===-- DWARFAbbreviationDeclaration.h --------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_DEBUGINFO_DWARFABBREVIATIONDECLARATION_H
+#define LLVM_DEBUGINFO_DWARFABBREVIATIONDECLARATION_H
+
+#include "DWARFAttribute.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/Support/DataExtractor.h"
+
+namespace llvm {
+
+class raw_ostream;
+
+class DWARFAbbreviationDeclaration {
+  uint32_t Code;
+  uint32_t Tag;
+  bool HasChildren;
+  SmallVector<DWARFAttribute, 8> Attributes;
+public:
+  enum { InvalidCode = 0 };
+  DWARFAbbreviationDeclaration()
+    : Code(InvalidCode), Tag(0), HasChildren(0) {}
+
+  uint32_t getCode() const { return Code; }
+  uint32_t getTag() const { return Tag; }
+  bool hasChildren() const { return HasChildren; }
+  uint32_t getNumAttributes() const { return Attributes.size(); }
+  uint16_t getAttrByIndex(uint32_t idx) const {
+    return Attributes.size() > idx ? Attributes[idx].getAttribute() : 0;
+  }
+  uint16_t getFormByIndex(uint32_t idx) const {
+    return Attributes.size() > idx ? Attributes[idx].getForm() : 0;
+  }
+
+  uint32_t findAttributeIndex(uint16_t attr) const;
+  bool extract(DataExtractor data, uint32_t* offset_ptr);
+  bool extract(DataExtractor data, uint32_t* offset_ptr, uint32_t code);
+  bool isValid() const { return Code != 0 && Tag != 0; }
+  void dump(raw_ostream &OS) const;
+  const SmallVectorImpl<DWARFAttribute> &getAttributes() const {
+    return Attributes;
+  }
+};
+
+}
+
+#endif

lib/DebugInfo/DWARFAttribute.h

@@ -0,0 +1,30 @@
+//===-- DWARFAttribute.h ----------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_DEBUGINFO_DWARFATTRIBUTE_H
+#define LLVM_DEBUGINFO_DWARFATTRIBUTE_H
+
+#include "llvm/Support/DataTypes.h"
+
+namespace llvm {
+
+class DWARFAttribute {
+  uint16_t Attribute;
+  uint16_t Form;
+  public:
+  DWARFAttribute(uint16_t attr, uint16_t form)
+    : Attribute(attr), Form(form) {}
+
+  uint16_t getAttribute() const { return Attribute; }
+  uint16_t getForm() const { return Form; }
+};
+
+}
+
+#endif