[DWARF parser] Cleanup code in DWARFDebugAbbrev.

No functionality change.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207274 91177308-0d34-0410-b5e6-96231b3b80d8

lib/DebugInfo/DWARFContext.cpp

@@ -218,7 +218,7 @@ const DWARFDebugAbbrev *DWARFContext::getDebugAbbrev() {
   DataExtractor abbrData(getAbbrevSection(), isLittleEndian(), 0);
 
   Abbrev.reset(new DWARFDebugAbbrev());
-  Abbrev->parse(abbrData);
+  Abbrev->extract(abbrData);
   return Abbrev.get();
 }
 
@@ -228,7 +228,7 @@ const DWARFDebugAbbrev *DWARFContext::getDebugAbbrevDWO() {
 
   DataExtractor abbrData(getAbbrevDWOSection(), isLittleEndian(), 0);
   AbbrevDWO.reset(new DWARFDebugAbbrev());
-  AbbrevDWO->parse(abbrData);
+  AbbrevDWO->extract(abbrData);
   return AbbrevDWO.get();
 }
 

lib/DebugInfo/DWARFDebugAbbrev.cpp

@@ -12,24 +12,36 @@
 #include "llvm/Support/raw_ostream.h"
 using namespace llvm;
 
-bool DWARFAbbreviationDeclarationSet::extract(DataExtractor data,
-                                              uint32_t* offset_ptr) {
-  const uint32_t beginOffset = *offset_ptr;
-  Offset = beginOffset;
+DWARFAbbreviationDeclarationSet::DWARFAbbreviationDeclarationSet() {
   clear();
-  DWARFAbbreviationDeclaration abbrevDeclaration;
-  uint32_t prevAbbrAode = 0;
-  while (abbrevDeclaration.extract(data, offset_ptr)) {
-    Decls.push_back(abbrevDeclaration);
-    if (IdxOffset == 0) {
-      IdxOffset = abbrevDeclaration.getCode();
+}
+
+void DWARFAbbreviationDeclarationSet::clear() {
+  Offset = 0;
+  FirstAbbrCode = 0;
+  Decls.clear();
+}
+
+bool DWARFAbbreviationDeclarationSet::extract(DataExtractor Data,
+                                              uint32_t *OffsetPtr) {
+  clear();
+  const uint32_t BeginOffset = *OffsetPtr;
+  Offset = BeginOffset;
+  DWARFAbbreviationDeclaration AbbrDecl;
+  uint32_t PrevAbbrCode = 0;
+  while (AbbrDecl.extract(Data, OffsetPtr)) {
+    Decls.push_back(AbbrDecl);
+    if (FirstAbbrCode == 0) {
+      FirstAbbrCode = AbbrDecl.getCode();
     } else {
-      if (prevAbbrAode + 1 != abbrevDeclaration.getCode())
-        IdxOffset = UINT32_MAX;// Out of order indexes, we can't do O(1) lookups
+      if (PrevAbbrCode + 1 != AbbrDecl.getCode()) {
+        // Codes are not consecutive, can't do O(1) lookups.
+        FirstAbbrCode = UINT32_MAX;
       }
-    prevAbbrAode = abbrevDeclaration.getCode();
     }
-  return beginOffset != *offset_ptr;
+    PrevAbbrCode = AbbrDecl.getCode();
+  }
+  return BeginOffset != *OffsetPtr;
 }
 
 void DWARFAbbreviationDeclarationSet::dump(raw_ostream &OS) const {
@@ -38,48 +50,49 @@ void DWARFAbbreviationDeclarationSet::dump(raw_ostream &OS) const {
 }
 
 const DWARFAbbreviationDeclaration *
-DWARFAbbreviationDeclarationSet::getAbbreviationDeclaration(uint32_t abbrCode)
-  const {
-  if (IdxOffset == UINT32_MAX) {
+DWARFAbbreviationDeclarationSet::getAbbreviationDeclaration(
+    uint32_t AbbrCode) const {
+  if (FirstAbbrCode == UINT32_MAX) {
     for (const auto &Decl : Decls) {
-      if (Decl.getCode() == abbrCode)
+      if (Decl.getCode() == AbbrCode)
         return &Decl;
     }
-  } else {
-    uint32_t idx = abbrCode - IdxOffset;
-    if (idx < Decls.size())
-      return &Decls[idx];
-  }
     return nullptr;
   }
-
-DWARFDebugAbbrev::DWARFDebugAbbrev() :
-  AbbrevCollMap(),
-  PrevAbbrOffsetPos(AbbrevCollMap.end()) {}
-
-
-void DWARFDebugAbbrev::parse(DataExtractor data) {
-  uint32_t offset = 0;
-
-  while (data.isValidOffset(offset)) {
-    uint32_t initial_cu_offset = offset;
-    DWARFAbbreviationDeclarationSet abbrevDeclSet;
-
-    if (abbrevDeclSet.extract(data, &offset))
-      AbbrevCollMap[initial_cu_offset] = abbrevDeclSet;
-    else
-      break;
+  if (AbbrCode < FirstAbbrCode || AbbrCode >= FirstAbbrCode + Decls.size())
+    return nullptr;
+  return &Decls[AbbrCode - FirstAbbrCode];
+}
+
+DWARFDebugAbbrev::DWARFDebugAbbrev() {
+  clear();
+}
+
+void DWARFDebugAbbrev::clear() {
+  AbbrDeclSets.clear();
+  PrevAbbrOffsetPos = AbbrDeclSets.end();
+}
+
+void DWARFDebugAbbrev::extract(DataExtractor Data) {
+  clear();
+
+  uint32_t Offset = 0;
+  DWARFAbbreviationDeclarationSet AbbrDecls;
+  while (Data.isValidOffset(Offset)) {
+    uint32_t CUAbbrOffset = Offset;
+    if (!AbbrDecls.extract(Data, &Offset))
+      break;
+    AbbrDeclSets[CUAbbrOffset] = AbbrDecls;
   }
-  PrevAbbrOffsetPos = AbbrevCollMap.end();
 }
 
 void DWARFDebugAbbrev::dump(raw_ostream &OS) const {
-  if (AbbrevCollMap.empty()) {
+  if (AbbrDeclSets.empty()) {
     OS << "< EMPTY >\n";
     return;
   }
 
-  for (const auto &I : AbbrevCollMap) {
+  for (const auto &I : AbbrDeclSets) {
     OS << format("Abbrev table for offset: 0x%8.8" PRIx64 "\n", I.first);
     I.second.dump(OS);
   }
@@ -87,13 +100,12 @@ void DWARFDebugAbbrev::dump(raw_ostream &OS) const {
 
 const DWARFAbbreviationDeclarationSet*
 DWARFDebugAbbrev::getAbbreviationDeclarationSet(uint64_t CUAbbrOffset) const {
-  DWARFAbbreviationDeclarationCollMapConstIter End = AbbrevCollMap.end();
+  const auto End = AbbrDeclSets.end();
   if (PrevAbbrOffsetPos != End && PrevAbbrOffsetPos->first == CUAbbrOffset) {
     return &(PrevAbbrOffsetPos->second);
   }
 
-  DWARFAbbreviationDeclarationCollMapConstIter Pos =
-      AbbrevCollMap.find(CUAbbrOffset);
+  const auto Pos = AbbrDeclSets.find(CUAbbrOffset);
   if (Pos != End) {
     PrevAbbrOffsetPos = Pos;
     return &(Pos->second);

lib/DebugInfo/DWARFDebugAbbrev.h

@@ -17,48 +17,33 @@
 
 namespace llvm {
 
-typedef std::vector<DWARFAbbreviationDeclaration>
-  DWARFAbbreviationDeclarationColl;
-typedef DWARFAbbreviationDeclarationColl::iterator
-  DWARFAbbreviationDeclarationCollIter;
-typedef DWARFAbbreviationDeclarationColl::const_iterator
-  DWARFAbbreviationDeclarationCollConstIter;
-
 class DWARFAbbreviationDeclarationSet {
   uint32_t Offset;
-  uint32_t IdxOffset;
+  /// Code of the first abbreviation, if all abbreviations in the set have
+  /// consecutive codes. UINT32_MAX otherwise.
+  uint32_t FirstAbbrCode;
   std::vector<DWARFAbbreviationDeclaration> Decls;
+
 public:
-  DWARFAbbreviationDeclarationSet()
-    : Offset(0), IdxOffset(0) {}
+  DWARFAbbreviationDeclarationSet();
 
-  DWARFAbbreviationDeclarationSet(uint32_t offset, uint32_t idxOffset)
-    : Offset(offset), IdxOffset(idxOffset) {}
-
-  void clear() {
-    IdxOffset = 0;
-    Decls.clear();
-  }
   uint32_t getOffset() const { return Offset; }
   void dump(raw_ostream &OS) const;
-  bool extract(DataExtractor data, uint32_t* offset_ptr);
+  bool extract(DataExtractor Data, uint32_t *OffsetPtr);
 
   const DWARFAbbreviationDeclaration *
-    getAbbreviationDeclaration(uint32_t abbrCode) const;
+  getAbbreviationDeclaration(uint32_t AbbrCode) const;
+
+private:
+  void clear();
 };
 
 class DWARFDebugAbbrev {
-public:
   typedef std::map<uint64_t, DWARFAbbreviationDeclarationSet>
-    DWARFAbbreviationDeclarationCollMap;
-  typedef DWARFAbbreviationDeclarationCollMap::iterator
-    DWARFAbbreviationDeclarationCollMapIter;
-  typedef DWARFAbbreviationDeclarationCollMap::const_iterator
-    DWARFAbbreviationDeclarationCollMapConstIter;
+    DWARFAbbreviationDeclarationSetMap;
 
-private:
-  DWARFAbbreviationDeclarationCollMap AbbrevCollMap;
-  mutable DWARFAbbreviationDeclarationCollMapConstIter PrevAbbrOffsetPos;
+  DWARFAbbreviationDeclarationSetMap AbbrDeclSets;
+  mutable DWARFAbbreviationDeclarationSetMap::const_iterator PrevAbbrOffsetPos;
 
 public:
   DWARFDebugAbbrev();
@@ -67,7 +52,10 @@ public:
   getAbbreviationDeclarationSet(uint64_t CUAbbrOffset) const;
 
   void dump(raw_ostream &OS) const;
-  void parse(DataExtractor data);
+  void extract(DataExtractor Data);
+
+private:
+  void clear();
 };
 
 }