[DebugInfo/DWARF] generate aranges for CU even if it has .debug_aranges entry

[sugak]

Summary

Not all of the functions have entries in .debug_aranges, but there are always .debug_info entries for them. Currently, this generates aranges for all of the compilation unit if there are no .debug_arange entries (see how ParsedCUOffsets is used). But this is not completely correct, in practice, a compilation unit might have an entry in .debug_arange which doesn't cover all of the functions and it's .debug_infos still, have to be considered.
To solve the problem remove ParsedCUOffsets which is used to determine if a CU has a .debug_arages.

With this change I was able to get full locations in ASAN stack traces with llvm-symbolizer that previously were not decoded:
Before:

#2 0x7f9a8807b2bb in foo(bar<void ()>) (.../libfoo.so+0xff2bb)

After:

#2 0x7f1a85c8f2bb in fin foo(bar<void ()>) foo/foo.cpp:589

[aprantl]

Testcase?

[aprantl]

tools/llvm-dwarfdump/Statistics.cpp

2

This seems odd, did something go wrong with uploading this patch?

include/llvm/DebugInfo/DWARF/DWARFDebugAranges.h

 //===- DWARFDebugAranges.h --------------------------------------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_DEBUGINFO_DWARFDEBUGARANGES_H
 #define LLVM_DEBUGINFO_DWARFDEBUGARANGES_H
 
-#include "llvm/ADT/DenseSet.h"
 #include "llvm/Support/DataExtractor.h"
 #include <cstdint>
 #include <vector>
 
 namespace llvm {
 
 class DWARFContext;
 
struct RangeEndpoint {
     }
   };
 
   using RangeColl = std::vector<Range>;
   using RangeCollIterator = RangeColl::const_iterator;
 
   std::vector<RangeEndpoint> Endpoints;
   RangeColl Aranges;
-  DenseSet<uint32_t> ParsedCUOffsets;
 };
 
 } // end namespace llvm
 
 #endif // LLVM_DEBUGINFO_DWARFDEBUGARANGES_H

lib/DebugInfo/DWARF/DWARFDebugAranges.cpp

void DWARFDebugAranges::extract(DataExtractor DebugArangesData) {
 
   while (Set.extract(DebugArangesData, &Offset)) {
     uint32_t CUOffset = Set.getCompileUnitDIEOffset();
     for (const auto &Desc : Set.descriptors()) {
       uint64_t LowPC = Desc.Address;
       uint64_t HighPC = Desc.getEndAddress();
       appendRange(CUOffset, LowPC, HighPC);
     }
-    ParsedCUOffsets.insert(CUOffset);
   }
 }
 
 void DWARFDebugAranges::generate(DWARFContext *CTX) {
   clear();
   if (!CTX)
     return;
 
   // Extract aranges from .debug_aranges section.
   DataExtractor ArangesData(CTX->getDWARFObj().getARangeSection(),
                             CTX->isLittleEndian(), 0);
   extract(ArangesData);
 
   // Generate aranges from DIEs: even if .debug_aranges section is present,
   // it may describe only a small subset of compilation units, so we need to
   // manually build aranges for the rest of them.
   for (const auto &CU : CTX->compile_units()) {
     uint32_t CUOffset = CU->getOffset();
-    if (ParsedCUOffsets.insert(CUOffset).second) {
-      DWARFAddressRangesVector CURanges;
-      CU->collectAddressRanges(CURanges);
-      for (const auto &R : CURanges)
-        appendRange(CUOffset, R.LowPC, R.HighPC);
-    }
-  }
 
   construct();
 }
 
 void DWARFDebugAranges::clear() {
   Endpoints.clear();
   Aranges.clear();
-  ParsedCUOffsets.clear();
 }
 
 void DWARFDebugAranges::appendRange(uint32_t CUOffset, uint64_t LowPC,
                                     uint64_t HighPC) {
   if (LowPC >= HighPC)
     return;
   Endpoints.emplace_back(LowPC, CUOffset, true);
   Endpoints.emplace_back(HighPC, CUOffset, false);

lib/DebugInfo/DWARF/DWARFVerifier.cpp

 //===- DWARFVerifier.cpp --------------------------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 #include "SyntaxHighlighting.h"
+#include "llvm/ADT/DenseSet.h"
 #include "llvm/DebugInfo/DWARF/DWARFVerifier.h"
 #include "llvm/DebugInfo/DWARF/DWARFCompileUnit.h"
 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
 #include "llvm/DebugInfo/DWARF/DWARFDebugLine.h"
 #include "llvm/DebugInfo/DWARF/DWARFDie.h"
 #include "llvm/DebugInfo/DWARF/DWARFExpression.h"
 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
 #include "llvm/DebugInfo/DWARF/DWARFSection.h"

tools/llvm-dwarfdump/Statistics.cpp

 #include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/DenseSet.h"
 #include "llvm/DebugInfo/DIContext.h"
 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
 #include "llvm/DebugInfo/DWARF/DWARFDebugLoc.h"
 #include "llvm/Object/ObjectFile.h"
 
 #define DEBUG_TYPE "dwarfdump"
 using namespace llvm;
 using namespace object;