[DWARF] Make llvm-dwarfdump display location lists in a .dwp file correctly. Fixes PR38990.

Considers the index when extracting location lists from a .dwp file.
Majority of the patch by David Blaikie.

Reviewers: dblaikie

Differential revision: https://reviews.llvm.org/D53155

llvm-svn: 344807

1 files changed, 30 insertions, 18 deletions

diff --git a/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp b/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
index 6c3c62d86ef..dbac5a82b57 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
@@ -39,9 +39,10 @@ void DWARFUnitVector::addUnitsForSection(DWARFContext &C,
                                          DWARFSectionKind SectionKind) {
   const DWARFObject &D = C.getDWARFObj();
   addUnitsImpl(C, D, Section, C.getDebugAbbrev(), &D.getRangeSection(),
-               D.getStringSection(), D.getStringOffsetSection(),
-               &D.getAddrSection(), D.getLineSection(), D.isLittleEndian(),
-               false, false, SectionKind);
+               &D.getLocSection(), D.getStringSection(),
+               D.getStringOffsetSection(), &D.getAddrSection(),
+               D.getLineSection(), D.isLittleEndian(), false, false,
+               SectionKind);
 }
 
 void DWARFUnitVector::addUnitsForDWOSection(DWARFContext &C,
@@ -50,16 +51,18 @@ void DWARFUnitVector::addUnitsForDWOSection(DWARFContext &C,
                                             bool Lazy) {
   const DWARFObject &D = C.getDWARFObj();
   addUnitsImpl(C, D, DWOSection, C.getDebugAbbrevDWO(), &D.getRangeDWOSection(),
-               D.getStringDWOSection(), D.getStringOffsetDWOSection(),
-               &D.getAddrSection(), D.getLineDWOSection(), C.isLittleEndian(),
-               true, Lazy, SectionKind);
+               &D.getLocDWOSection(), D.getStringDWOSection(),
+               D.getStringOffsetDWOSection(), &D.getAddrSection(),
+               D.getLineDWOSection(), C.isLittleEndian(), true, Lazy,
+               SectionKind);
 }
 
 void DWARFUnitVector::addUnitsImpl(
     DWARFContext &Context, const DWARFObject &Obj, const DWARFSection &Section,
-    const DWARFDebugAbbrev *DA, const DWARFSection *RS, StringRef SS,
-    const DWARFSection &SOS, const DWARFSection *AOS, const DWARFSection &LS,
-    bool LE, bool IsDWO, bool Lazy, DWARFSectionKind SectionKind) {
+    const DWARFDebugAbbrev *DA, const DWARFSection *RS,
+    const DWARFSection *LocSection, StringRef SS, const DWARFSection &SOS,
+    const DWARFSection *AOS, const DWARFSection &LS, bool LE, bool IsDWO,
+    bool Lazy, DWARFSectionKind SectionKind) {
   DWARFDataExtractor Data(Obj, Section, LE, 0);
   // Lazy initialization of Parser, now that we have all section info.
   if (!Parser) {
@@ -79,12 +82,12 @@ void DWARFUnitVector::addUnitsImpl(
       std::unique_ptr<DWARFUnit> U;
       if (Header.isTypeUnit())
         U = llvm::make_unique<DWARFTypeUnit>(Context, InfoSection, Header, DA,
-                                             RS, SS, SOS, AOS, LS, LE, IsDWO,
-                                             *this);
+                                             RS, LocSection, SS, SOS, AOS, LS,
+                                             LE, IsDWO, *this);
       else
         U = llvm::make_unique<DWARFCompileUnit>(Context, InfoSection, Header,
-                                                DA, RS, SS, SOS, AOS, LS, LE,
-                                                IsDWO, *this);
+                                                DA, RS, LocSection, SS, SOS,
+                                                AOS, LS, LE, IsDWO, *this);
       return U;
     };
   }
@@ -164,16 +167,25 @@ DWARFUnitVector::getUnitForIndexEntry(const DWARFUnitIndex::Entry &E) {
 }
 
 DWARFUnit::DWARFUnit(DWARFContext &DC, const DWARFSection &Section,
-                     const DWARFUnitHeader &Header,
-                     const DWARFDebugAbbrev *DA, const DWARFSection *RS,
+                     const DWARFUnitHeader &Header, const DWARFDebugAbbrev *DA,
+                     const DWARFSection *RS, const DWARFSection *LocSection,
                      StringRef SS, const DWARFSection &SOS,
                      const DWARFSection *AOS, const DWARFSection &LS, bool LE,
                      bool IsDWO, const DWARFUnitVector &UnitVector)
     : Context(DC), InfoSection(Section), Header(Header), Abbrev(DA),
-      RangeSection(RS), LineSection(LS), StringSection(SS),
-      StringOffsetSection(SOS),  AddrOffsetSection(AOS), isLittleEndian(LE),
-      isDWO(IsDWO), UnitVector(UnitVector) {
+      RangeSection(RS), LocSection(LocSection), LineSection(LS),
+      StringSection(SS), StringOffsetSection(SOS), AddrOffsetSection(AOS),
+      isLittleEndian(LE), isDWO(IsDWO), UnitVector(UnitVector) {
   clear();
+  // For split DWARF we only need to keep track of the location list section's
+  // data (no relocations), and if we are reading a package file, we need to
+  // adjust the location list data based on the index entries.
+  if (IsDWO) {
+    LocSectionData = LocSection->Data;
+    if (auto *IndexEntry = Header.getIndexEntry())
+      if (const auto *C = IndexEntry->getOffset(DW_SECT_LOC))
+        LocSectionData = LocSectionData.substr(C->Offset, C->Length);
+  }
 }
 
 DWARFUnit::~DWARFUnit() = default;