Update LLVM for rebase to r212749.

Includes a cherry-pick of:
r212948 - fixes a small issue with atomic calls

Change-Id: Ib97bd980b59f18142a69506400911a6009d9df18

6 files changed, 74 insertions, 63 deletions

diff --git a/lib/DebugInfo/DWARFContext.cpp b/lib/DebugInfo/DWARFContext.cpp
index e52e8af..3961905 100644
--- a/lib/DebugInfo/DWARFContext.cpp
+++ b/lib/DebugInfo/DWARFContext.cpp
@@ -734,7 +734,7 @@ DWARFContextInMemory::DWARFContextInMemory(object::ObjectFile *Obj)
         object::RelocToApply R(V.visit(Type, Reloc, 0, SymAddr));
         if (V.error()) {
           SmallString<32> Name;
-          error_code ec(Reloc.getTypeName(Name));
+          std::error_code ec(Reloc.getTypeName(Name));
           if (ec) {
             errs() << "Aaaaaa! Nameless relocation! Aaaaaa!\n";
           }
diff --git a/lib/DebugInfo/DWARFDebugAranges.cpp b/lib/DebugInfo/DWARFDebugAranges.cpp
index 2524adc..fe7e46d 100644
--- a/lib/DebugInfo/DWARFDebugAranges.cpp
+++ b/lib/DebugInfo/DWARFDebugAranges.cpp
@@ -15,6 +15,7 @@
 #include "llvm/Support/raw_ostream.h"
 #include <algorithm>
 #include <cassert>
+#include <set>
 using namespace llvm;
 
 void DWARFDebugAranges::extract(DataExtractor DebugArangesData) {
@@ -30,6 +31,7 @@ void DWARFDebugAranges::extract(DataExtractor DebugArangesData) {
       uint64_t HighPC = Desc.getEndAddress();
       appendRange(CUOffset, LowPC, HighPC);
     }
+    ParsedCUOffsets.insert(CUOffset);
   }
 }
 
@@ -56,69 +58,55 @@ void DWARFDebugAranges::generate(DWARFContext *CTX) {
     }
   }
 
-  sortAndMinimize();
+  construct();
 }
 
 void DWARFDebugAranges::clear() {
+  Endpoints.clear();
   Aranges.clear();
   ParsedCUOffsets.clear();
 }
 
 void DWARFDebugAranges::appendRange(uint32_t CUOffset, uint64_t LowPC,
                                     uint64_t HighPC) {
-  if (!Aranges.empty()) {
-    if (Aranges.back().CUOffset == CUOffset &&
-        Aranges.back().HighPC() == LowPC) {
-      Aranges.back().setHighPC(HighPC);
-      return;
-    }
-  }
-  Aranges.push_back(Range(LowPC, HighPC, CUOffset));
-}
-
-void DWARFDebugAranges::sortAndMinimize() {
-  const size_t orig_arange_size = Aranges.size();
-  // Size of one? If so, no sorting is needed
-  if (orig_arange_size <= 1)
+  if (LowPC >= HighPC)
     return;
-  // Sort our address range entries
-  std::stable_sort(Aranges.begin(), Aranges.end());
-
-  // Most address ranges are contiguous from function to function
-  // so our new ranges will likely be smaller. We calculate the size
-  // of the new ranges since although std::vector objects can be resized,
-  // the will never reduce their allocated block size and free any excesss
-  // memory, so we might as well start a brand new collection so it is as
-  // small as possible.
-
-  // First calculate the size of the new minimal arange vector
-  // so we don't have to do a bunch of re-allocations as we
-  // copy the new minimal stuff over to the new collection.
-  size_t minimal_size = 1;
-  for (size_t i = 1; i < orig_arange_size; ++i) {
-    if (!Range::SortedOverlapCheck(Aranges[i-1], Aranges[i]))
-      ++minimal_size;
-  }
+  Endpoints.emplace_back(LowPC, CUOffset, true);
+  Endpoints.emplace_back(HighPC, CUOffset, false);
+}
 
-  // Else, make a new RangeColl that _only_ contains what we need.
-  RangeColl minimal_aranges;
-  minimal_aranges.resize(minimal_size);
-  uint32_t j = 0;
-  minimal_aranges[j] = Aranges[0];
-  for (size_t i = 1; i < orig_arange_size; ++i) {
-    if (Range::SortedOverlapCheck(minimal_aranges[j], Aranges[i])) {
-      minimal_aranges[j].setHighPC(Aranges[i].HighPC());
+void DWARFDebugAranges::construct() {
+  std::multiset<uint32_t> ValidCUs;  // Maintain the set of CUs describing
+                                     // a current address range.
+  std::sort(Endpoints.begin(), Endpoints.end());
+  uint64_t PrevAddress = -1ULL;
+  for (const auto &E : Endpoints) {
+    if (PrevAddress < E.Address && ValidCUs.size() > 0) {
+      // If the address range between two endpoints is described by some
+      // CU, first try to extend the last range in Aranges. If we can't
+      // do it, start a new range.
+      if (!Aranges.empty() && Aranges.back().HighPC() == PrevAddress &&
+          ValidCUs.find(Aranges.back().CUOffset) != ValidCUs.end()) {
+        Aranges.back().setHighPC(E.Address);
+      } else {
+        Aranges.emplace_back(PrevAddress, E.Address, *ValidCUs.begin());
+      }
+    }
+    // Update the set of valid CUs.
+    if (E.IsRangeStart) {
+      ValidCUs.insert(E.CUOffset);
     } else {
-      // Only increment j if we aren't merging
-      minimal_aranges[++j] = Aranges[i];
+      auto CUPos = ValidCUs.find(E.CUOffset);
+      assert(CUPos != ValidCUs.end());
+      ValidCUs.erase(CUPos);
     }
+    PrevAddress = E.Address;
   }
-  assert(j+1 == minimal_size);
+  assert(ValidCUs.empty());
 
-  // Now swap our new minimal aranges into place. The local
-  // minimal_aranges will then contian the old big collection
-  // which will get freed.
-  minimal_aranges.swap(Aranges);
+  // Endpoints are not needed now.
+  std::vector<RangeEndpoint> EmptyEndpoints;
+  EmptyEndpoints.swap(Endpoints);
 }
 
 uint32_t DWARFDebugAranges::findAddress(uint64_t Address) const {
diff --git a/lib/DebugInfo/DWARFDebugAranges.h b/lib/DebugInfo/DWARFDebugAranges.h
index de96d7f..a9f37fe 100644
--- a/lib/DebugInfo/DWARFDebugAranges.h
+++ b/lib/DebugInfo/DWARFDebugAranges.h
@@ -27,9 +27,9 @@ private:
   void clear();
   void extract(DataExtractor DebugArangesData);
 
-  // Use appendRange multiple times and then call sortAndMinimize.
+  // Call appendRange multiple times and then call construct.
   void appendRange(uint32_t CUOffset, uint64_t LowPC, uint64_t HighPC);
-  void sortAndMinimize();
+  void construct();
 
   struct Range {
     explicit Range(uint64_t LowPC = -1ULL, uint64_t HighPC = -1ULL,
@@ -47,31 +47,39 @@ private:
         return LowPC + Length;
       return -1ULL;
     }
+
     bool containsAddress(uint64_t Address) const {
       return LowPC <= Address && Address < HighPC();
     }
-
-    bool operator <(const Range &other) const {
+    bool operator<(const Range &other) const {
       return LowPC < other.LowPC;
     }
 
-    static bool SortedOverlapCheck(const Range &Left, const Range &Right) {
-      if (Left.CUOffset != Right.CUOffset)
-        return false;
-      return Left.HighPC() >= Right.LowPC;
-    }
-
     uint64_t LowPC; // Start of address range.
     uint32_t Length; // End of address range (not including this address).
     uint32_t CUOffset; // Offset of the compile unit or die.
   };
 
+  struct RangeEndpoint {
+    uint64_t Address;
+    uint32_t CUOffset;
+    bool IsRangeStart;
+
+    RangeEndpoint(uint64_t Address, uint32_t CUOffset, bool IsRangeStart)
+        : Address(Address), CUOffset(CUOffset), IsRangeStart(IsRangeStart) {}
+
+    bool operator<(const RangeEndpoint &Other) const {
+      return Address < Other.Address;
+    }
+  };
+
+
   typedef std::vector<Range>              RangeColl;
   typedef RangeColl::const_iterator       RangeCollIterator;
-  typedef DenseSet<uint32_t>              ParsedCUOffsetColl;
 
+  std::vector<RangeEndpoint> Endpoints;
   RangeColl Aranges;
-  ParsedCUOffsetColl ParsedCUOffsets;
+  DenseSet<uint32_t> ParsedCUOffsets;
 };
 
 }
diff --git a/lib/DebugInfo/DWARFDebugInfoEntry.cpp b/lib/DebugInfo/DWARFDebugInfoEntry.cpp
index b811ed7..2e7a54a 100644
--- a/lib/DebugInfo/DWARFDebugInfoEntry.cpp
+++ b/lib/DebugInfo/DWARFDebugInfoEntry.cpp
@@ -210,6 +210,16 @@ uint64_t DWARFDebugInfoEntryMinimal::getAttributeValueAsSectionOffset(
   return Result.hasValue() ? Result.getValue() : FailValue;
 }
 
+uint64_t
+DWARFDebugInfoEntryMinimal::getRangesBaseAttribute(const DWARFUnit *U,
+                                                   uint64_t FailValue) const {
+  uint64_t Result =
+      getAttributeValueAsSectionOffset(U, DW_AT_ranges_base, -1ULL);
+  if (Result != -1ULL)
+    return Result;
+  return getAttributeValueAsSectionOffset(U, DW_AT_GNU_ranges_base, FailValue);
+}
+
 bool DWARFDebugInfoEntryMinimal::getLowAndHighPC(const DWARFUnit *U,
                                                  uint64_t &LowPC,
                                                  uint64_t &HighPC) const {
diff --git a/lib/DebugInfo/DWARFDebugInfoEntry.h b/lib/DebugInfo/DWARFDebugInfoEntry.h
index 916e1ed..cc58eb6 100644
--- a/lib/DebugInfo/DWARFDebugInfoEntry.h
+++ b/lib/DebugInfo/DWARFDebugInfoEntry.h
@@ -106,6 +106,8 @@ public:
                                             const uint16_t Attr,
                                             uint64_t FailValue) const;
 
+  uint64_t getRangesBaseAttribute(const DWARFUnit *U, uint64_t FailValue) const;
+
   /// Retrieves DW_AT_low_pc and DW_AT_high_pc from CU.
   /// Returns true if both attributes are present.
   bool getLowAndHighPC(const DWARFUnit *U, uint64_t &LowPC,
diff --git a/lib/DebugInfo/DWARFUnit.cpp b/lib/DebugInfo/DWARFUnit.cpp
index f5f5072..39d0a0f 100644
--- a/lib/DebugInfo/DWARFUnit.cpp
+++ b/lib/DebugInfo/DWARFUnit.cpp
@@ -226,7 +226,9 @@ size_t DWARFUnit::extractDIEsIfNeeded(bool CUDieOnly) {
     AddrOffsetSectionBase = DieArray[0].getAttributeValueAsSectionOffset(
         this, DW_AT_GNU_addr_base, 0);
     RangeSectionBase = DieArray[0].getAttributeValueAsSectionOffset(
-        this, DW_AT_GNU_ranges_base, 0);
+        this, DW_AT_ranges_base, 0);
+    // Don't fall back to DW_AT_GNU_ranges_base: it should be ignored for
+    // skeleton CU DIE, so that DWARF users not aware of it are not broken.
   }
 
   setDIERelations();
@@ -272,7 +274,8 @@ bool DWARFUnit::parseDWO() {
   }
   // Share .debug_addr and .debug_ranges section with compile unit in .dwo
   DWOCU->setAddrOffsetSection(AddrOffsetSection, AddrOffsetSectionBase);
-  DWOCU->setRangesSection(RangeSection, RangeSectionBase);
+  uint32_t DWORangesBase = DieArray[0].getRangesBaseAttribute(this, 0);
+  DWOCU->setRangesSection(RangeSection, DWORangesBase);
   return true;
 }