DWARFAbbreviationDeclaration: remove dead code, refactor parsing code and make it more robust. No functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193770 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 60 insertions, 75 deletions

diff --git a/lib/DebugInfo/DWARFAbbreviationDeclaration.cpp b/lib/DebugInfo/DWARFAbbreviationDeclaration.cpp
index 2de62ab..f46fd58 100644
--- a/lib/DebugInfo/DWARFAbbreviationDeclaration.cpp
+++ b/lib/DebugInfo/DWARFAbbreviationDeclaration.cpp
@@ -14,37 +14,51 @@
 using namespace llvm;
 using namespace dwarf;
 
-bool
-DWARFAbbreviationDeclaration::extract(DataExtractor data, uint32_t* offset_ptr){
-  return extract(data, offset_ptr, data.getULEB128(offset_ptr));
+void DWARFAbbreviationDeclaration::clear() {
+  Code = 0;
+  Tag = 0;
+  HasChildren = false;
+  Attributes.clear();
 }
 
-bool
-DWARFAbbreviationDeclaration::extract(DataExtractor data, uint32_t* offset_ptr,
-                                      uint32_t code) {
-  Code = code;
-  Attribute.clear();
-  if (Code) {
-    Tag = data.getULEB128(offset_ptr);
-    HasChildren = data.getU8(offset_ptr);
+DWARFAbbreviationDeclaration::DWARFAbbreviationDeclaration() {
+  clear();
+}
 
-    while (data.isValidOffset(*offset_ptr)) {
-      uint16_t attr = data.getULEB128(offset_ptr);
-      uint16_t form = data.getULEB128(offset_ptr);
+bool
+DWARFAbbreviationDeclaration::extract(DataExtractor Data, uint32_t* OffsetPtr) {
+  clear();
+  Code = Data.getULEB128(OffsetPtr);
+  if (Code == 0) {
+    return false;
+  }
+  Tag = Data.getULEB128(OffsetPtr);
+  uint8_t ChildrenByte = Data.getU8(OffsetPtr);
+  HasChildren = (ChildrenByte == DW_CHILDREN_yes);
 
-      if (attr && form)
-        Attribute.push_back(DWARFAttribute(attr, form));
-      else
-        break;
+  while (true) {
+    uint32_t CurOffset = *OffsetPtr;
+    uint16_t Attr = Data.getULEB128(OffsetPtr);
+    if (CurOffset == *OffsetPtr) {
+      clear();
+      return false;
     }
-
-    return Tag != 0;
-  } else {
-    Tag = 0;
-    HasChildren = false;
+    CurOffset = *OffsetPtr;
+    uint16_t Form = Data.getULEB128(OffsetPtr);
+    if (CurOffset == *OffsetPtr) {
+      clear();
+      return false;
+    }
+    if (Attr == 0 && Form == 0)
+      break;
+    Attributes.push_back(AttributeSpec(Attr, Form));
   }
 
-  return false;
+  if (Tag == 0) {
+    clear();
+    return false;
+  }
+  return true;
 }
 
 void DWARFAbbreviationDeclaration::dump(raw_ostream &OS) const {
@@ -55,19 +69,19 @@ void DWARFAbbreviationDeclaration::dump(raw_ostream &OS) const {
   else
     OS << format("DW_TAG_Unknown_%x", getTag());
   OS << "\tDW_CHILDREN_" << (hasChildren() ? "yes" : "no") << '\n';
-  for (unsigned i = 0, e = Attribute.size(); i != e; ++i) {
+  for (unsigned i = 0, e = Attributes.size(); i != e; ++i) {
     OS << '\t';
-    const char *attrString = AttributeString(Attribute[i].getAttribute());
+    const char *attrString = AttributeString(Attributes[i].Attr);
     if (attrString)
       OS << attrString;
     else
-      OS << format("DW_AT_Unknown_%x", Attribute[i].getAttribute());
+      OS << format("DW_AT_Unknown_%x", Attributes[i].Attr);
     OS << '\t';
-    const char *formString = FormEncodingString(Attribute[i].getForm());
+    const char *formString = FormEncodingString(Attributes[i].Form);
     if (formString)
       OS << formString;
     else
-      OS << format("DW_FORM_Unknown_%x", Attribute[i].getForm());
+      OS << format("DW_FORM_Unknown_%x", Attributes[i].Form);
     OS << '\n';
   }
   OS << '\n';
@@ -75,8 +89,8 @@ void DWARFAbbreviationDeclaration::dump(raw_ostream &OS) const {
 
 uint32_t
 DWARFAbbreviationDeclaration::findAttributeIndex(uint16_t attr) const {
-  for (uint32_t i = 0, e = Attribute.size(); i != e; ++i) {
-    if (Attribute[i].getAttribute() == attr)
+  for (uint32_t i = 0, e = Attributes.size(); i != e; ++i) {
+    if (Attributes[i].Attr == attr)
       return i;
   }
   return -1U;
diff --git a/lib/DebugInfo/DWARFAbbreviationDeclaration.h b/lib/DebugInfo/DWARFAbbreviationDeclaration.h
index 9a3fcd8..e9b072e 100644
--- a/lib/DebugInfo/DWARFAbbreviationDeclaration.h
+++ b/lib/DebugInfo/DWARFAbbreviationDeclaration.h
@@ -10,7 +10,6 @@
 #ifndef LLVM_DEBUGINFO_DWARFABBREVIATIONDECLARATION_H
 #define LLVM_DEBUGINFO_DWARFABBREVIATIONDECLARATION_H
 
-#include "DWARFAttribute.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Support/DataExtractor.h"
 
@@ -22,31 +21,33 @@ class DWARFAbbreviationDeclaration {
   uint32_t Code;
   uint32_t Tag;
   bool HasChildren;
-  SmallVector<DWARFAttribute, 8> Attribute;
+
+  struct AttributeSpec {
+    AttributeSpec(uint16_t Attr, uint16_t Form) : Attr(Attr), Form(Form) {}
+    uint16_t Attr;
+    uint16_t Form;
+  };
+  SmallVector<AttributeSpec, 8> Attributes;
 public:
-  enum { InvalidCode = 0 };
-  DWARFAbbreviationDeclaration()
-    : Code(InvalidCode), Tag(0), HasChildren(0) {}
+  DWARFAbbreviationDeclaration();
 
   uint32_t getCode() const { return Code; }
   uint32_t getTag() const { return Tag; }
   bool hasChildren() const { return HasChildren; }
-  uint32_t getNumAttributes() const { return Attribute.size(); }
+  uint32_t getNumAttributes() const { return Attributes.size(); }
   uint16_t getAttrByIndex(uint32_t idx) const {
-    return Attribute.size() > idx ? Attribute[idx].getAttribute() : 0;
+    return idx < Attributes.size() ? Attributes[idx].Attr : 0;
   }
   uint16_t getFormByIndex(uint32_t idx) const {
-    return Attribute.size() > idx ? Attribute[idx].getForm() : 0;
+    return idx < Attributes.size() ? Attributes[idx].Form : 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; }
+  bool extract(DataExtractor Data, uint32_t* OffsetPtr);
   void dump(raw_ostream &OS) const;
-  const SmallVectorImpl<DWARFAttribute> &getAttributes() const {
-    return Attribute;
-  }
+
+private:
+  void clear();
 };
 
 }
diff --git a/lib/DebugInfo/DWARFAttribute.h b/lib/DebugInfo/DWARFAttribute.h
deleted file mode 100644
index 6f49b63..0000000
--- a/lib/DebugInfo/DWARFAttribute.h
+++ /dev/null
@@ -1,30 +0,0 @@
-//===-- 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