dwarfdump: Delay parsing abbreviations until they're needed

This speeds up dumping specific DIEs by not parsing abbreviations for
units that are not used.

(this is also handy to have in eventually to speed up llvm-symbolizer
for .dwp files, where parsing most of the DWP file can be avoided by
using the index)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@313635 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h b/include/llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h
index 963f285c109c996b10d89519d69c29aa29a212b0..d277ec382ba56be432497b84179e9414311f061a 100644 (file)
--- a/include/llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h
+++ b/include/llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h
@@ -56,8 +56,9 @@ class DWARFDebugAbbrev {
   using DWARFAbbreviationDeclarationSetMap =
       std::map<uint64_t, DWARFAbbreviationDeclarationSet>;
 
-  DWARFAbbreviationDeclarationSetMap AbbrDeclSets;
+  mutable DWARFAbbreviationDeclarationSetMap AbbrDeclSets;
   mutable DWARFAbbreviationDeclarationSetMap::const_iterator PrevAbbrOffsetPos;
+  mutable Optional<DataExtractor> Data;
 
 public:
   DWARFDebugAbbrev();
@@ -66,10 +67,11 @@ public:
   getAbbreviationDeclarationSet(uint64_t CUAbbrOffset) const;
 
   void dump(raw_ostream &OS) const;
+  void parse() const;
   void extract(DataExtractor Data);
-  bool empty() const { return begin() == end(); }
 
   DWARFAbbreviationDeclarationSetMap::const_iterator begin() const {
+    parse();
     return AbbrDeclSets.begin();
   }
 

diff --git a/include/llvm/DebugInfo/DWARF/DWARFUnit.h b/include/llvm/DebugInfo/DWARF/DWARFUnit.h
index 6e85e71e5b34ca219962aede36e937af648967b4..ebe8cc66d4f703a8ef828c3222898eaac63212a1 100644 (file)
--- a/include/llvm/DebugInfo/DWARF/DWARFUnit.h
+++ b/include/llvm/DebugInfo/DWARF/DWARFUnit.h
@@ -139,7 +139,8 @@ class DWARFUnit {
 
   uint32_t Offset;
   uint32_t Length;
-  const DWARFAbbreviationDeclarationSet *Abbrevs;
+  mutable const DWARFAbbreviationDeclarationSet *Abbrevs;
+  uint64_t AbbrOffset;
   uint8_t UnitType;
   llvm::Optional<BaseAddress> BaseAddr;
   /// The compile unit debug information entry items.
@@ -231,9 +232,7 @@ public:
     return FormParams.getDwarfOffsetByteSize();
   }
 
-  const DWARFAbbreviationDeclarationSet *getAbbreviations() const {
-    return Abbrevs;
-  }
+  const DWARFAbbreviationDeclarationSet *getAbbreviations() const;
 
   uint8_t getUnitType() const { return UnitType; }
 

diff --git a/lib/DebugInfo/DWARF/DWARFDebugAbbrev.cpp b/lib/DebugInfo/DWARF/DWARFDebugAbbrev.cpp
index 76dd2e4c21bcc0f3058c3c5542e31d499437a3d5..4830c36a8ee791209e558571c8e3b5d2995e4bb0 100644 (file)
--- a/lib/DebugInfo/DWARF/DWARFDebugAbbrev.cpp
+++ b/lib/DebugInfo/DWARF/DWARFDebugAbbrev.cpp
@@ -68,9 +68,7 @@ DWARFAbbreviationDeclarationSet::getAbbreviationDeclaration(
   return &Decls[AbbrCode - FirstAbbrCode];
 }
 
-DWARFDebugAbbrev::DWARFDebugAbbrev() {
-  clear();
-}
+DWARFDebugAbbrev::DWARFDebugAbbrev() { clear(); }
 
 void DWARFDebugAbbrev::clear() {
   AbbrDeclSets.clear();
@@ -79,18 +77,29 @@ void DWARFDebugAbbrev::clear() {
 
 void DWARFDebugAbbrev::extract(DataExtractor Data) {
   clear();
+  this->Data = Data;
+}
 
+void DWARFDebugAbbrev::parse() const {
+  if (!Data)
+    return;
   uint32_t Offset = 0;
   DWARFAbbreviationDeclarationSet AbbrDecls;
-  while (Data.isValidOffset(Offset)) {
+  auto I = AbbrDeclSets.begin();
+  while (Data->isValidOffset(Offset)) {
+    while (I != AbbrDeclSets.end() && I->first < Offset)
+      ++I;
     uint32_t CUAbbrOffset = Offset;
-    if (!AbbrDecls.extract(Data, &Offset))
+    if (!AbbrDecls.extract(*Data, &Offset))
       break;
-    AbbrDeclSets[CUAbbrOffset] = std::move(AbbrDecls);
+    AbbrDeclSets.insert(I, std::make_pair(CUAbbrOffset, std::move(AbbrDecls)));
   }
+  Data = None;
 }
 
 void DWARFDebugAbbrev::dump(raw_ostream &OS) const {
+  parse();
+
   if (AbbrDeclSets.empty()) {
     OS << "< EMPTY >\n";
     return;
@@ -115,5 +124,16 @@ DWARFDebugAbbrev::getAbbreviationDeclarationSet(uint64_t CUAbbrOffset) const {
     return &(Pos->second);
   }
 
+  if (Data && CUAbbrOffset < Data->getData().size()) {
+    uint32_t Offset = CUAbbrOffset;
+    DWARFAbbreviationDeclarationSet AbbrDecls;
+    if (!AbbrDecls.extract(*Data, &Offset))
+      return nullptr;
+    PrevAbbrOffsetPos =
+        AbbrDeclSets.insert(std::make_pair(CUAbbrOffset, std::move(AbbrDecls)))
+            .first;
+    return &PrevAbbrOffsetPos->second;
+  }
+
   return nullptr;
 }

diff --git a/lib/DebugInfo/DWARF/DWARFUnit.cpp b/lib/DebugInfo/DWARF/DWARFUnit.cpp
index 813960ca95d783e5ebcf45f0c66a8ee2449462d6..4467b4ac30944080b4cd136e482b5139b0867a2b 100644 (file)
--- a/lib/DebugInfo/DWARF/DWARFUnit.cpp
+++ b/lib/DebugInfo/DWARF/DWARFUnit.cpp
@@ -94,7 +94,6 @@ bool DWARFUnit::extractImpl(DataExtractor debug_info, uint32_t *offset_ptr) {
   // FIXME: Support DWARF64.
   FormParams.Format = DWARF32;
   FormParams.Version = debug_info.getU16(offset_ptr);
-  uint64_t AbbrOffset;
   if (FormParams.Version >= 5) {
     UnitType = debug_info.getU8(offset_ptr);
     FormParams.AddrSize = debug_info.getU8(offset_ptr);
@@ -124,9 +123,7 @@ bool DWARFUnit::extractImpl(DataExtractor debug_info, uint32_t *offset_ptr) {
 
   // Keep track of the highest DWARF version we encounter across all units.
   Context.setMaxVersionIfGreater(getVersion());
-
-  Abbrevs = Abbrev->getAbbreviationDeclarationSet(AbbrOffset);
-  return Abbrevs != nullptr;
+  return true;
 }
 
 bool DWARFUnit::extract(DataExtractor debug_info, uint32_t *offset_ptr) {
@@ -452,3 +449,9 @@ DWARFDie DWARFUnit::getSibling(const DWARFDebugInfoEntry *Die) {
   }
   return DWARFDie();
 }
+
+const DWARFAbbreviationDeclarationSet *DWARFUnit::getAbbreviations() const {
+  if (!Abbrevs)
+    Abbrevs = Abbrev->getAbbreviationDeclarationSet(AbbrOffset);
+  return Abbrevs;
+}