DWARFDebugLoclists: Add an api to get the location lists of a DWARF unit

Summary:
This avoid the need to duplicate the location lists searching logic in
various users. The "inline location list dumping" code (which is the
only user actually updated to handle DWARF v5 location lists)  is
switched to this method. After adding v4 location list support, I'll
switch other users too.

Reviewers: dblaikie, probinson, JDevlieghere, aprantl, SouraVX

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70084

2 files changed, 34 insertions, 40 deletions

diff --git a/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp b/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp
index 22ae8ebb649..308f731570c 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp
@@ -92,49 +92,35 @@ static void dumpLocation(raw_ostream &OS, DWARFFormValue &FormValue,
   }
 
   if (FormValue.isFormClass(DWARFFormValue::FC_SectionOffset)) {
+    auto LLDumpOpts = DumpOpts;
+    LLDumpOpts.Verbose = false;
+
     uint64_t Offset = *FormValue.getAsSectionOffset();
     uint64_t BaseAddr = 0;
     if (Optional<object::SectionedAddress> BA = U->getBaseAddress())
       BaseAddr = BA->Address;
-    auto LLDumpOpts = DumpOpts;
-    LLDumpOpts.Verbose = false;
-
-    if (!U->isDWOUnit() && !U->getLocSection()->Data.empty()) {
-      DWARFDebugLoc DebugLoc;
-      DWARFDataExtractor Data(Obj, *U->getLocSection(), Ctx.isLittleEndian(),
-                              Obj.getAddressSize());
-
-      FormValue.dump(OS, DumpOpts);
-      OS << ": ";
 
-      if (Expected<DWARFDebugLoc::LocationList> LL =
-              DebugLoc.parseOneLocationList(Data, &Offset)) {
-        LL->dump(OS, BaseAddr, Ctx.isLittleEndian(), Obj.getAddressSize(), MRI,
-                 U, LLDumpOpts, Indent);
-      } else {
-        OS << '\n';
-        OS.indent(Indent);
-        OS << formatv("error extracting location list: {0}",
-                      fmt_consume(LL.takeError()));
-      }
+    if (const DWARFLocationTable *LT = U->getLocationTable()) {
+      LT->dumpLocationList(&Offset, OS, BaseAddr, MRI, U, LLDumpOpts, Indent);
       return;
     }
 
-    bool UseLocLists = !U->isDWOUnit();
-    auto Data =
-        UseLocLists
-            ? DWARFDataExtractor(Obj, Obj.getLoclistsSection(),
-                                 Ctx.isLittleEndian(), Obj.getAddressSize())
-            : DWARFDataExtractor(U->getLocSectionData(), Ctx.isLittleEndian(),
-                                 Obj.getAddressSize());
-
-    if (!Data.getData().empty()) {
-      // Old-style location list were used in DWARF v4 (.debug_loc.dwo section).
-      // Modern locations list (.debug_loclists) are used starting from v5.
-      // Ideally we should take the version from the .debug_loclists section
-      // header, but using CU's version for simplicity.
-      DWARFDebugLoclists(Data, UseLocLists ? U->getVersion() : 4)
-          .dumpLocationList(&Offset, OS, BaseAddr, MRI, U, LLDumpOpts, Indent);
+    DWARFDebugLoc DebugLoc;
+    DWARFDataExtractor Data(Obj, *U->getLocSection(), Ctx.isLittleEndian(),
+                            Obj.getAddressSize());
+
+    FormValue.dump(OS, DumpOpts);
+    OS << ": ";
+
+    if (Expected<DWARFDebugLoc::LocationList> LL =
+            DebugLoc.parseOneLocationList(Data, &Offset)) {
+      LL->dump(OS, BaseAddr, Ctx.isLittleEndian(), Obj.getAddressSize(), MRI, U,
+               LLDumpOpts, Indent);
+    } else {
+      OS << '\n';
+      OS.indent(Indent);
+      OS << formatv("error extracting location list: {0}",
+                    fmt_consume(LL.takeError()));
     }
     return;
   }
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp b/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
index a56402a707a..81c7959f646 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
@@ -179,14 +179,22 @@ DWARFUnit::DWARFUnit(DWARFContext &DC, const DWARFSection &Section,
       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 we are reading a package file, we need to adjust the location list
+    // data based on the index entries.
+    StringRef Data = LocSection->Data;
     if (auto *IndexEntry = Header.getIndexEntry())
       if (const auto *C = IndexEntry->getOffset(DW_SECT_LOC))
-        LocSectionData = LocSectionData.substr(C->Offset, C->Length);
+        Data = Data.substr(C->Offset, C->Length);
+    LocTable = std::make_unique<DWARFDebugLoclists>(
+        DWARFDataExtractor(Data, isLittleEndian, getAddressByteSize()),
+        Header.getVersion());
+  } else if (Header.getVersion() >= 5) {
+    LocTable = std::make_unique<DWARFDebugLoclists>(
+        DWARFDataExtractor(Context.getDWARFObj(),
+                           Context.getDWARFObj().getLoclistsSection(),
+                           isLittleEndian, getAddressByteSize()),
+        Header.getVersion());
   }
 }