[DWARF] - Take relocations in account when extracting ranges from .debug_ranges

I found this when investigated "Bug 32319 - .gdb_index is broken/incomplete" for LLD.

When we have object file with .debug_ranges section it may be filled with zeroes.
Relocations are exist in file to relocate this zeroes into real values later, but until that
a pair of zeroes is treated as terminator. And DWARF parser thinks there is no ranges at all
when I am trying to collect address ranges for building .gdb_index.

Solution implemented in this patch is to take relocations in account when parsing ranges.

Differential revision: https://reviews.llvm.org/D32228

llvm-svn: 301170

3 files changed, 22 insertions, 14 deletions

diff --git a/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp b/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
index f01050c83ba..7e8d04672c0 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
@@ -222,11 +222,11 @@ void DWARFContext::dump(raw_ostream &OS, DIDumpType DumpType, bool DumpEH,
     // sizes, but for simplicity we just use the address byte size of the last
     // compile unit (there is no easy and fast way to associate address range
     // list and the compile unit it describes).
-    DataExtractor rangesData(getRangeSection(), isLittleEndian(),
+    DataExtractor rangesData(getRangeSection().Data, isLittleEndian(),
                              savedAddressByteSize);
     offset = 0;
     DWARFDebugRangeList rangeList;
-    while (rangeList.extract(rangesData, &offset))
+    while (rangeList.extract(rangesData, &offset, getRangeSection().Relocs))
       rangeList.dump(OS);
   }
 
@@ -732,7 +732,7 @@ DWARFContextInMemory::DWARFContextInMemory(const object::ObjectFile &Obj,
       *SectionData = data;
       if (name == "debug_ranges") {
         // FIXME: Use the other dwo range section when we emit it.
-        RangeDWOSection = data;
+        RangeDWOSection.Data = data;
       }
     } else if (name == "debug_types") {
       // Find debug_types data by section rather than name as there are
@@ -773,6 +773,7 @@ DWARFContextInMemory::DWARFContextInMemory(const object::ObjectFile &Obj,
         .Case("debug_loc", &LocSection.Relocs)
         .Case("debug_info.dwo", &InfoDWOSection.Relocs)
         .Case("debug_line", &LineSection.Relocs)
+        .Case("debug_ranges", &RangeSection.Relocs)
         .Case("apple_names", &AppleNamesSection.Relocs)
         .Case("apple_types", &AppleTypesSection.Relocs)
         .Case("apple_namespaces", &AppleNamespacesSection.Relocs)
@@ -855,7 +856,7 @@ StringRef *DWARFContextInMemory::MapSectionToMember(StringRef Name) {
       .Case("debug_frame", &DebugFrameSection)
       .Case("eh_frame", &EHFrameSection)
       .Case("debug_str", &StringSection)
-      .Case("debug_ranges", &RangeSection)
+      .Case("debug_ranges", &RangeSection.Data)
       .Case("debug_macinfo", &MacinfoSection)
       .Case("debug_pubnames", &PubNamesSection)
       .Case("debug_pubtypes", &PubTypesSection)
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFDebugRangeList.cpp b/llvm/lib/DebugInfo/DWARF/DWARFDebugRangeList.cpp
index f1d82fda8c0..9380fe8fe85 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFDebugRangeList.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFDebugRangeList.cpp
@@ -7,6 +7,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/DebugInfo/DWARF/DWARFContext.h"
 #include "llvm/DebugInfo/DWARF/DWARFDebugRangeList.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/raw_ostream.h"
@@ -22,7 +23,8 @@ void DWARFDebugRangeList::clear() {
   Entries.clear();
 }
 
-bool DWARFDebugRangeList::extract(DataExtractor data, uint32_t *offset_ptr) {
+bool DWARFDebugRangeList::extract(DataExtractor data, uint32_t *offset_ptr,
+                                  const RelocAddrMap &Relocs) {
   clear();
   if (!data.isValidOffset(*offset_ptr))
     return false;
@@ -33,8 +35,11 @@ bool DWARFDebugRangeList::extract(DataExtractor data, uint32_t *offset_ptr) {
   while (true) {
     RangeListEntry entry;
     uint32_t prev_offset = *offset_ptr;
-    entry.StartAddress = data.getAddress(offset_ptr);
-    entry.EndAddress = data.getAddress(offset_ptr);
+    entry.StartAddress =
+        getRelocatedValue(data, AddressSize, offset_ptr, &Relocs);
+    entry.EndAddress =
+        getRelocatedValue(data, AddressSize, offset_ptr, &Relocs);
+
     // Check that both values were extracted correctly.
     if (*offset_ptr != prev_offset + 2 * AddressSize) {
       clear();
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp b/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
index c3f46774540..f50487fc3ba 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
@@ -32,7 +32,7 @@ using namespace llvm;
 using namespace dwarf;
 
 void DWARFUnitSectionBase::parse(DWARFContext &C, const DWARFSection &Section) {
-  parseImpl(C, Section, C.getDebugAbbrev(), C.getRangeSection(),
+  parseImpl(C, Section, C.getDebugAbbrev(), &C.getRangeSection(),
             C.getStringSection(), StringRef(), C.getAddrSection(),
             C.getLineSection().Data, C.isLittleEndian(), false);
 }
@@ -40,16 +40,17 @@ void DWARFUnitSectionBase::parse(DWARFContext &C, const DWARFSection &Section) {
 void DWARFUnitSectionBase::parseDWO(DWARFContext &C,
                                     const DWARFSection &DWOSection,
                                     DWARFUnitIndex *Index) {
-  parseImpl(C, DWOSection, C.getDebugAbbrevDWO(), C.getRangeDWOSection(),
+  parseImpl(C, DWOSection, C.getDebugAbbrevDWO(), &C.getRangeDWOSection(),
             C.getStringDWOSection(), C.getStringOffsetDWOSection(),
             C.getAddrSection(), C.getLineDWOSection().Data, C.isLittleEndian(),
             true);
 }
 
 DWARFUnit::DWARFUnit(DWARFContext &DC, const DWARFSection &Section,
-                     const DWARFDebugAbbrev *DA, StringRef RS, StringRef SS,
-                     StringRef SOS, StringRef AOS, StringRef LS, bool LE,
-                     bool IsDWO, const DWARFUnitSectionBase &UnitSection,
+                     const DWARFDebugAbbrev *DA, const DWARFSection *RS,
+                     StringRef SS, StringRef SOS, StringRef AOS, StringRef LS,
+                     bool LE, bool IsDWO,
+                     const DWARFUnitSectionBase &UnitSection,
                      const DWARFUnitIndex::Entry *IndexEntry)
     : Context(DC), InfoSection(Section), Abbrev(DA), RangeSection(RS),
       LineSection(LS), StringSection(SS), StringOffsetSection([&]() {
@@ -142,9 +143,10 @@ bool DWARFUnit::extractRangeList(uint32_t RangeListOffset,
                                         DWARFDebugRangeList &RangeList) const {
   // Require that compile unit is extracted.
   assert(!DieArray.empty());
-  DataExtractor RangesData(RangeSection, isLittleEndian, AddrSize);
+  DataExtractor RangesData(RangeSection->Data, isLittleEndian, AddrSize);
   uint32_t ActualRangeListOffset = RangeSectionBase + RangeListOffset;
-  return RangeList.extract(RangesData, &ActualRangeListOffset);
+  return RangeList.extract(RangesData, &ActualRangeListOffset,
+                           RangeSection->Relocs);
 }
 
 void DWARFUnit::clear() {