llvm-symbolizer: Fix bug related to TUs interfering with symbolizing

With the merge of TUs and CUs into a single container, some code that
relied on the CU range having an ordered range of contiguous addresses
(for locating a CU at a given offset) broke. But the units from
debug_info (currently only CUs, but CUs and TUs in DWARFv5) are in a
contiguous sub-range of that container - searching only through that
subrange is still valid & so do that.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@341889 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/DebugInfo/DWARF/DWARFUnit.h

@@ -110,7 +110,7 @@ class DWARFUnitVector final : public SmallVector<std::unique_ptr<DWARFUnit>, 1>
   std::function<std::unique_ptr<DWARFUnit>(uint32_t, DWARFSectionKind,
                                            const DWARFSection *)>
       Parser;
-  unsigned NumInfoUnits = 0;
+  int NumInfoUnits = -1;
 
 public:
   using UnitVector = SmallVectorImpl<std::unique_ptr<DWARFUnit>>;
@@ -135,11 +135,13 @@ public:
                              DWARFSectionKind SectionKind, bool Lazy = false);
 
   /// Returns number of all units held by this instance.
-  unsigned getNumUnits() { return size(); }
+  unsigned getNumUnits() const { return size(); }
   /// Returns number of units from all .debug_info[.dwo] sections.
-  unsigned getNumInfoUnits() { return NumInfoUnits; }
+  unsigned getNumInfoUnits() const {
+    return NumInfoUnits == -1 ? size() : NumInfoUnits;
+  }
   /// Returns number of units from all .debug_types[.dwo] sections.
-  unsigned getNumTypesUnits() { return size() - NumInfoUnits; }
+  unsigned getNumTypesUnits() const { return size() - NumInfoUnits; }
   /// Indicate that parsing .debug_info[.dwo] is done, and remaining units
   /// will be from .debug_types[.dwo].
   void finishedInfoUnits() { NumInfoUnits = size(); }

lib/DebugInfo/DWARF/DWARFUnit.cpp

@@ -113,12 +113,13 @@ void DWARFUnitVector::addUnitsImpl(
 }
 
 DWARFUnit *DWARFUnitVector::getUnitForOffset(uint32_t Offset) const {
-  auto *CU = std::upper_bound(
-    this->begin(), this->end(), Offset,
-    [](uint32_t LHS, const std::unique_ptr<DWARFUnit> &RHS) {
-    return LHS < RHS->getNextUnitOffset();
-  });
-  if (CU != this->end() && (*CU)->getOffset() <= Offset)
+  auto end = begin() + getNumInfoUnits();
+  auto *CU =
+      std::upper_bound(begin(), end, Offset,
+                       [](uint32_t LHS, const std::unique_ptr<DWARFUnit> &RHS) {
+                         return LHS < RHS->getNextUnitOffset();
+                       });
+  if (CU != end && (*CU)->getOffset() <= Offset)
     return CU->get();
   return nullptr;
 }
@@ -130,13 +131,14 @@ DWARFUnitVector::getUnitForIndexEntry(const DWARFUnitIndex::Entry &E) {
     return nullptr;
 
   auto Offset = CUOff->Offset;
+  auto end = begin() + getNumInfoUnits();
 
-  auto *CU = std::upper_bound(
-    this->begin(), this->end(), CUOff->Offset,
-    [](uint32_t LHS, const std::unique_ptr<DWARFUnit> &RHS) {
-    return LHS < RHS->getNextUnitOffset();
-  });
-  if (CU != this->end() && (*CU)->getOffset() <= Offset)
+  auto *CU =
+      std::upper_bound(begin(), end, CUOff->Offset,
+                       [](uint32_t LHS, const std::unique_ptr<DWARFUnit> &RHS) {
+                         return LHS < RHS->getNextUnitOffset();
+                       });
+  if (CU != end && (*CU)->getOffset() <= Offset)
     return CU->get();
 
   if (!Parser)
@@ -148,6 +150,7 @@ DWARFUnitVector::getUnitForIndexEntry(const DWARFUnitIndex::Entry &E) {
 
   auto *NewCU = U.get();
   this->insert(CU, std::move(U));
+  ++NumInfoUnits;
   return NewCU;
 }
 

test/DebugInfo/llvm-symbolizer-tu.test

@@ -0,0 +1,8 @@
+RUN: echo "%p/Inputs/llvm-symbolizer-tu.elf-x86-64 0x0" \
+RUN:   | llvm-symbolizer | FileCheck %s
+
+Built from the following source:
+
+...
+
+CHECK: b.cpp:3:0