[llvm-dwarfdump] - Add the support of parsing .debug_loclists.

This teaches llvm-dwarfdump to dump the content of .debug_loclists sections.

It converts the DWARFDebugLocDWO class to DWARFDebugLoclists,
teaches llvm-dwarfdump about .debug_loclists section and
adds the implementation for parsing the DW_LLE_offset_pair entries.

Differential revision: https://reviews.llvm.org/D53364

llvm-svn: 344895

3 files changed, 108 insertions, 28 deletions

diff --git a/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp b/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
index 18ec8476e9d..1f3753809a2 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
@@ -292,6 +292,27 @@ dumpRnglistsSection(raw_ostream &OS, DWARFDataExtractor &rnglistData,
   }
 }
 
+static void dumpLoclistsSection(raw_ostream &OS, DIDumpOptions DumpOpts,
+                                DWARFDataExtractor Data,
+                                const MCRegisterInfo *MRI,
+                                Optional<uint64_t> DumpOffset) {
+  uint32_t Offset = 0;
+  DWARFDebugLoclists Loclists;
+
+  DWARFListTableHeader Header(".debug_loclists", "locations");
+  if (Error E = Header.extract(Data, &Offset)) {
+    WithColor::error() << toString(std::move(E)) << '\n';
+    return;
+  }
+
+  Header.dump(OS, DumpOpts);
+  DataExtractor LocData(Data.getData().drop_front(Offset),
+                        Data.isLittleEndian(), Header.getAddrSize());
+
+  Loclists.parse(LocData);
+  Loclists.dump(OS, 0, MRI, DumpOffset);
+}
+
 void DWARFContext::dump(
     raw_ostream &OS, DIDumpOptions DumpOpts,
     std::array<Optional<uint64_t>, DIDT_ID_Count> DumpOffsets) {
@@ -366,9 +387,15 @@ void DWARFContext::dump(
                  DObj->getLocSection().Data)) {
     getDebugLoc()->dump(OS, getRegisterInfo(), DumpOffset);
   }
+  if (shouldDump(Explicit, ".debug_loclists", DIDT_ID_DebugLoclists,
+                 DObj->getLoclistsSection().Data)) {
+    DWARFDataExtractor Data(*DObj, DObj->getLoclistsSection(), isLittleEndian(),
+                            0);
+    dumpLoclistsSection(OS, DumpOpts, Data, getRegisterInfo(), DumpOffset);
+  }
   if (shouldDump(ExplicitDWO, ".debug_loc.dwo", DIDT_ID_DebugLoc,
                  DObj->getLocDWOSection().Data)) {
-    getDebugLocDWO()->dump(OS, getRegisterInfo(), DumpOffset);
+    getDebugLocDWO()->dump(OS, 0, getRegisterInfo(), DumpOffset);
   }
 
   if (shouldDump(Explicit, ".debug_frame", DIDT_ID_DebugFrame,
@@ -696,11 +723,11 @@ const DWARFDebugLoc *DWARFContext::getDebugLoc() {
   return Loc.get();
 }
 
-const DWARFDebugLocDWO *DWARFContext::getDebugLocDWO() {
+const DWARFDebugLoclists *DWARFContext::getDebugLocDWO() {
   if (LocDWO)
     return LocDWO.get();
 
-  LocDWO.reset(new DWARFDebugLocDWO());
+  LocDWO.reset(new DWARFDebugLoclists());
   // Assume all compile units have the same address byte size.
   // FIXME: We don't need AddressSize for split DWARF since relocatable
   // addresses cannot appear there. At the moment DWARFExpression requires it.
@@ -1213,6 +1240,7 @@ class DWARFObjInMemory final : public DWARFObject {
 
   DWARFSectionMap InfoSection;
   DWARFSectionMap LocSection;
+  DWARFSectionMap LocListsSection;
   DWARFSectionMap LineSection;
   DWARFSectionMap RangeSection;
   DWARFSectionMap RnglistsSection;
@@ -1234,6 +1262,7 @@ class DWARFObjInMemory final : public DWARFObject {
     return StringSwitch<DWARFSectionMap *>(Name)
         .Case("debug_info", &InfoSection)
         .Case("debug_loc", &LocSection)
+        .Case("debug_loclists", &LocListsSection)
         .Case("debug_line", &LineSection)
         .Case("debug_str_offsets", &StringOffsetSection)
         .Case("debug_ranges", &RangeSection)
@@ -1529,6 +1558,7 @@ public:
 
   StringRef getAbbrevSection() const override { return AbbrevSection; }
   const DWARFSection &getLocSection() const override { return LocSection; }
+  const DWARFSection &getLoclistsSection() const override { return LocListsSection; }
   StringRef getARangeSection() const override { return ARangeSection; }
   StringRef getDebugFrameSection() const override { return DebugFrameSection; }
   StringRef getEHFrameSection() const override { return EHFrameSection; }
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFDebugLoc.cpp b/llvm/lib/DebugInfo/DWARF/DWARFDebugLoc.cpp
index 617b914ecce..bfcf799d230 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFDebugLoc.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFDebugLoc.cpp
@@ -144,24 +144,39 @@ void DWARFDebugLoc::parse(const DWARFDataExtractor &data) {
     WithColor::error() << "failed to consume entire .debug_loc section\n";
 }
 
-Optional<DWARFDebugLocDWO::LocationList>
-DWARFDebugLocDWO::parseOneLocationList(DataExtractor Data, unsigned *Offset) {
+Optional<DWARFDebugLoclists::LocationList>
+DWARFDebugLoclists::parseOneLocationList(DataExtractor Data, unsigned *Offset) {
   LocationList LL;
   LL.Offset = *Offset;
 
   // dwarf::DW_LLE_end_of_list_entry is 0 and indicates the end of the list.
   while (auto Kind =
              static_cast<dwarf::LocationListEntry>(Data.getU8(Offset))) {
-    if (Kind != dwarf::DW_LLE_startx_length) {
+
+    Entry E;
+    E.Kind = Kind;
+    switch (Kind) {
+    case dwarf::DW_LLE_startx_length:
+      E.Value0 = Data.getULEB128(Offset);
+      E.Value1 = Data.getU32(Offset);
+      break;
+    case dwarf::DW_LLE_start_length:
+      E.Value0 = Data.getAddress(Offset);
+      E.Value1 = Data.getULEB128(Offset);
+      break;
+    case dwarf::DW_LLE_offset_pair:
+      E.Value0 = Data.getULEB128(Offset);
+      E.Value1 = Data.getULEB128(Offset);
+      break;
+    case dwarf::DW_LLE_base_address:
+      E.Value0 = Data.getAddress(Offset);
+      break;
+    default:
       WithColor::error() << "dumping support for LLE of kind " << (int)Kind
                          << " not implemented\n";
       return None;
     }
 
-    Entry E;
-    E.Start = Data.getULEB128(Offset);
-    E.Length = Data.getU32(Offset);
-
     unsigned Bytes = Data.getU16(Offset);
     // A single location description describing the location of the object...
     StringRef str = Data.getData().substr(*Offset, Bytes);
@@ -174,7 +189,7 @@ DWARFDebugLocDWO::parseOneLocationList(DataExtractor Data, unsigned *Offset) {
   return LL;
 }
 
-void DWARFDebugLocDWO::parse(DataExtractor data) {
+void DWARFDebugLoclists::parse(DataExtractor data) {
   IsLittleEndian = data.isLittleEndian();
   AddressSize = data.getAddressSize();
 
@@ -187,8 +202,8 @@ void DWARFDebugLocDWO::parse(DataExtractor data) {
   }
 }
 
-DWARFDebugLocDWO::LocationList const *
-DWARFDebugLocDWO::getLocationListAtOffset(uint64_t Offset) const {
+DWARFDebugLoclists::LocationList const *
+DWARFDebugLoclists::getLocationListAtOffset(uint64_t Offset) const {
   auto It = std::lower_bound(
       Locations.begin(), Locations.end(), Offset,
       [](const LocationList &L, uint64_t Offset) { return L.Offset < Offset; });
@@ -197,23 +212,46 @@ DWARFDebugLocDWO::getLocationListAtOffset(uint64_t Offset) const {
   return nullptr;
 }
 
-void DWARFDebugLocDWO::LocationList::dump(raw_ostream &OS, bool IsLittleEndian,
-                                          unsigned AddressSize,
-                                          const MCRegisterInfo *MRI,
-                                          unsigned Indent) const {
+void DWARFDebugLoclists::LocationList::dump(raw_ostream &OS, uint64_t BaseAddr,
+                                            bool IsLittleEndian,
+                                            unsigned AddressSize,
+                                            const MCRegisterInfo *MRI,
+                                            unsigned Indent) const {
   for (const Entry &E : Entries) {
-    OS << '\n';
-    OS.indent(Indent);
-    OS << "Addr idx " << E.Start << " (w/ length " << E.Length << "): ";
+    switch (E.Kind) {
+    case dwarf::DW_LLE_startx_length:
+      OS << '\n';
+      OS.indent(Indent);
+      OS << "Addr idx " << E.Value0 << " (w/ length " << E.Value1 << "): ";
+      break;
+    case dwarf::DW_LLE_start_length:
+      OS << '\n';
+      OS.indent(Indent);
+      OS << format("[0x%8.8x, 0x%8.8x): ", E.Value0, E.Value0 + E.Value1);
+      break;
+    case dwarf::DW_LLE_offset_pair:
+      OS << '\n';
+      OS.indent(Indent);
+      OS << format("[0x%8.8x, 0x%8.8x): ", BaseAddr + E.Value0,
+                   BaseAddr + E.Value1);
+      break;
+    case dwarf::DW_LLE_base_address:
+      BaseAddr = E.Value0;
+      break;
+    default:
+      llvm_unreachable("unreachable locations list kind");
+    }
+
     dumpExpression(OS, E.Loc, IsLittleEndian, AddressSize, MRI);
   }
 }
 
-void DWARFDebugLocDWO::dump(raw_ostream &OS, const MCRegisterInfo *MRI,
-                            Optional<uint64_t> Offset) const {
+void DWARFDebugLoclists::dump(raw_ostream &OS, uint64_t BaseAddr,
+                              const MCRegisterInfo *MRI,
+                              Optional<uint64_t> Offset) const {
   auto DumpLocationList = [&](const LocationList &L) {
     OS << format("0x%8.8x: ", L.Offset);
-    L.dump(OS, IsLittleEndian, AddressSize, MRI, /*Indent=*/12);
+    L.dump(OS, BaseAddr, IsLittleEndian, AddressSize, MRI, /*Indent=*/12);
     OS << "\n\n";
   };
 
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp b/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp
index b4413653290..76430b41f18 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp
@@ -102,7 +102,7 @@ static void dumpLocation(raw_ostream &OS, DWARFFormValue &FormValue,
   FormValue.dump(OS, DumpOpts);
   if (FormValue.isFormClass(DWARFFormValue::FC_SectionOffset)) {
     uint32_t Offset = *FormValue.getAsSectionOffset();
-    if (!U->isDWOUnit()) {
+    if (!U->isDWOUnit() && !U->getLocSection()->Data.empty()) {
       DWARFDebugLoc DebugLoc;
       DWARFDataExtractor Data(Obj, *U->getLocSection(), Ctx.isLittleEndian(),
                               Obj.getAddressSize());
@@ -115,11 +115,23 @@ static void dumpLocation(raw_ostream &OS, DWARFFormValue &FormValue,
                  Indent);
       } else
         OS << "error extracting location list.";
-    } else {
-      DataExtractor Data(U->getLocSectionData(), Ctx.isLittleEndian(), 0);
-      auto LL = DWARFDebugLocDWO::parseOneLocationList(Data, &Offset);
+      return;
+    }
+
+    StringRef LoclistsSectionData =
+        U->isDWOUnit() ? U->getLocSectionData() : Obj.getLoclistsSection().Data;
+    if (!LoclistsSectionData.empty()) {
+      DataExtractor Data(LoclistsSectionData, Ctx.isLittleEndian(),
+                         Obj.getAddressSize());
+      auto LL = DWARFDebugLoclists::parseOneLocationList(Data, &Offset);
+
+      uint64_t BaseAddr = 0;
+      if (Optional<SectionedAddress> BA = U->getBaseAddress())
+        BaseAddr = BA->Address;
+
       if (LL)
-        LL->dump(OS, Ctx.isLittleEndian(), Obj.getAddressSize(), MRI, Indent);
+        LL->dump(OS, BaseAddr, Ctx.isLittleEndian(), Obj.getAddressSize(), MRI,
+                 Indent);
       else
         OS << "error extracting location list.";
     }