Reapply "NFC: DebugInfo: Refactor RangeSpanList to be a struct, like DebugLocStream::List"

Move these data structures closer together so their emission code can
eventually share more of its implementation.

Was an egregious bug (completely untested, evidently) where I hadn't
inverted a DWARFv5 test as needed, so it was doing the exact opposite of
what was required & thus tried to emit a DWARFv5 range list header in
DWARFv4.

Reapply 8e04896288d22ed8bef7ac367923374f96b753d6 which was
reverted in a8154e5e0c83d2f0f65f3b4fb1a0bc68785bd975.

4 files changed, 11 insertions, 19 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index 0f3d8c689fa..5707f962b4b 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -503,10 +503,10 @@ void DwarfCompileUnit::addScopeRangeList(DIE &ScopeDIE,
     const MCSymbol *RangeSectionSym =
         TLOF.getDwarfRangesSection()->getBeginSymbol();
     if (isDwoUnit())
-      addSectionDelta(ScopeDIE, dwarf::DW_AT_ranges, List.getSym(),
+      addSectionDelta(ScopeDIE, dwarf::DW_AT_ranges, List.Label,
                       RangeSectionSym);
     else
-      addSectionLabel(ScopeDIE, dwarf::DW_AT_ranges, List.getSym(),
+      addSectionLabel(ScopeDIE, dwarf::DW_AT_ranges, List.Label,
                       RangeSectionSym);
   }
 }
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index b8905ce5c9d..6d62d4b3e69 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -2331,7 +2331,7 @@ static MCSymbol *emitRnglistsTableHeader(AsmPrinter *Asm,
   Asm->OutStreamer->EmitLabel(Holder.getRnglistsTableBaseSym());
 
   for (const RangeSpanList &List : Holder.getRangeLists())
-    Asm->EmitLabelDifference(List.getSym(), Holder.getRnglistsTableBaseSym(),
+    Asm->EmitLabelDifference(List.Label, Holder.getRnglistsTableBaseSym(),
                              4);
 
   return TableEnd;
@@ -2688,11 +2688,11 @@ void DwarfDebug::emitDebugARanges() {
 /// Emit a single range list. We handle both DWARF v5 and earlier.
 static void emitRangeList(DwarfDebug &DD, AsmPrinter *Asm,
                           const RangeSpanList &List) {
-  emitRangeList(DD, Asm, List.getSym(), List.getRanges(), List.getCU(),
+  emitRangeList(DD, Asm, List.Label, List.Ranges, *List.CU,
                 dwarf::DW_RLE_base_addressx, dwarf::DW_RLE_offset_pair,
                 dwarf::DW_RLE_startx_length, dwarf::DW_RLE_end_of_list,
                 llvm::dwarf::RangeListEncodingString,
-                List.getCU().getCUNode()->getRangesBaseAddress() ||
+                List.CU->getCUNode()->getRangesBaseAddress() ||
                     DD.getDwarfVersion() >= 5,
                 [](auto) {});
 }
@@ -2709,8 +2709,9 @@ void DwarfDebug::emitDebugRangesImpl(const DwarfFile &Holder, MCSection *Section
 
   Asm->OutStreamer->SwitchSection(Section);
 
-  MCSymbol *TableEnd =
-      getDwarfVersion() < 5 ? nullptr : emitRnglistsTableHeader(Asm, Holder);
+  MCSymbol *TableEnd = nullptr;
+  if (getDwarfVersion() >= 5)
+    TableEnd = emitRnglistsTableHeader(Asm, Holder);
 
   for (const RangeSpanList &List : Holder.getRangeLists())
     emitRangeList(*this, Asm, List);
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfFile.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfFile.cpp
index e3c9095d134..e5c4db58f47 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfFile.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfFile.cpp
@@ -126,6 +126,6 @@ void DwarfFile::addScopeLabel(LexicalScope *LS, DbgLabel *Label) {
 std::pair<uint32_t, RangeSpanList *>
 DwarfFile::addRange(const DwarfCompileUnit &CU, SmallVector<RangeSpan, 2> R) {
   CURangeLists.push_back(
-      RangeSpanList(Asm->createTempSymbol("debug_ranges"), CU, std::move(R)));
+      RangeSpanList{Asm->createTempSymbol("debug_ranges"), &CU, std::move(R)});
   return std::make_pair(CURangeLists.size() - 1, &CURangeLists.back());
 }
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfFile.h b/llvm/lib/CodeGen/AsmPrinter/DwarfFile.h
index 35fa51fb24c..cf293d7534d 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfFile.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfFile.h
@@ -37,21 +37,12 @@ struct RangeSpan {
   const MCSymbol *End;
 };
 
-class RangeSpanList {
-private:
+struct RangeSpanList {
   // Index for locating within the debug_range section this particular span.
-  MCSymbol *RangeSym;
+  MCSymbol *Label;
   const DwarfCompileUnit *CU;
   // List of ranges.
   SmallVector<RangeSpan, 2> Ranges;
-
-public:
-  RangeSpanList(MCSymbol *Sym, const DwarfCompileUnit &CU,
-                SmallVector<RangeSpan, 2> Ranges)
-      : RangeSym(Sym), CU(&CU), Ranges(std::move(Ranges)) {}
-  MCSymbol *getSym() const { return RangeSym; }
-  const DwarfCompileUnit &getCU() const { return *CU; }
-  const SmallVectorImpl<RangeSpan> &getRanges() const { return Ranges; }
 };
 
 class DwarfFile {