[llvm] r342099 - dwarfdump: Improve performance on large DWP files

[David Blaikie via llvm-commits]

Author: dblaikie
Date: Wed Sep 12 16:39:51 2018
New Revision: 342099

URL: http://llvm.org/viewvc/llvm-project?rev=342099&view=rev
Log:
dwarfdump: Improve performance on large DWP files

Modified:
    llvm/trunk/include/llvm/ADT/STLExtras.h
    llvm/trunk/include/llvm/DebugInfo/DWARF/DWARFUnitIndex.h
    llvm/trunk/lib/DebugInfo/DWARF/DWARFUnitIndex.cpp

Modified: llvm/trunk/include/llvm/ADT/STLExtras.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/STLExtras.h?rev=342099&r1=342098&r2=342099&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ADT/STLExtras.h (original)
+++ llvm/trunk/include/llvm/ADT/STLExtras.h Wed Sep 12 16:39:51 2018
@@ -1130,6 +1130,13 @@ auto lower_bound(R &&Range, ForwardIt I)
   return std::lower_bound(adl_begin(Range), adl_end(Range), I);
 }
 
+/// Provide wrappers to std::upper_bound which take ranges instead of having to
+/// pass begin/end explicitly.
+template <typename R, typename ForwardIt>
+auto upper_bound(R &&Range, ForwardIt I) -> decltype(adl_begin(Range)) {
+  return std::upper_bound(adl_begin(Range), adl_end(Range), I);
+}
+
 /// Wrapper function around std::equal to detect if all elements
 /// in a container are same.
 template <typename R>

Modified: llvm/trunk/include/llvm/DebugInfo/DWARF/DWARFUnitIndex.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/DebugInfo/DWARF/DWARFUnitIndex.h?rev=342099&r1=342098&r2=342099&view=diff
==============================================================================
--- llvm/trunk/include/llvm/DebugInfo/DWARF/DWARFUnitIndex.h (original)
+++ llvm/trunk/include/llvm/DebugInfo/DWARF/DWARFUnitIndex.h Wed Sep 12 16:39:51 2018
@@ -74,6 +74,7 @@ private:
   int InfoColumn = -1;
   std::unique_ptr<DWARFSectionKind[]> ColumnKinds;
   std::unique_ptr<Entry[]> Rows;
+  mutable std::vector<Entry *> OffsetLookup;
 
   static StringRef getColumnHeader(DWARFSectionKind DS);
 

Modified: llvm/trunk/lib/DebugInfo/DWARF/DWARFUnitIndex.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/DebugInfo/DWARF/DWARFUnitIndex.cpp?rev=342099&r1=342098&r2=342099&view=diff
==============================================================================
--- llvm/trunk/lib/DebugInfo/DWARF/DWARFUnitIndex.cpp (original)
+++ llvm/trunk/lib/DebugInfo/DWARF/DWARFUnitIndex.cpp Wed Sep 12 16:39:51 2018
@@ -164,14 +164,27 @@ DWARFUnitIndex::Entry::getOffset() const
 
 const DWARFUnitIndex::Entry *
 DWARFUnitIndex::getFromOffset(uint32_t Offset) const {
-  for (uint32_t i = 0; i != Header.NumBuckets; ++i)
-    if (const auto &Contribs = Rows[i].Contributions) {
-      const auto &InfoContrib = Contribs[InfoColumn];
-      if (InfoContrib.Offset <= Offset &&
-          Offset < (InfoContrib.Offset + InfoContrib.Length))
-        return &Rows[i];
-    }
-  return nullptr;
+  if (OffsetLookup.empty()) {
+    for (uint32_t i = 0; i != Header.NumBuckets; ++i)
+      if (const auto &Contribs = Rows[i].Contributions)
+        OffsetLookup.push_back(&Rows[i]);
+    llvm::sort(OffsetLookup, [&](Entry *E1, Entry *E2) {
+      return E1->Contributions[InfoColumn].Offset <
+             E2->Contributions[InfoColumn].Offset;
+    });
+  }
+  auto I =
+      llvm::upper_bound(OffsetLookup, Offset, [&](uint32_t Offset, Entry *E2) {
+        return Offset < E2->Contributions[InfoColumn].Offset;
+      });
+  if (I == OffsetLookup.begin())
+    return nullptr;
+  --I;
+  const auto *E = *I;
+  const auto &InfoContrib = E->Contributions[InfoColumn];
+  if ((InfoContrib.Offset + InfoContrib.Length) <= Offset)
+    return nullptr;
+  return E;
 }
 
 const DWARFUnitIndex::Entry *DWARFUnitIndex::getFromHash(uint64_t S) const {