DebugInfo: Move loclist base address from DwarfFile to DebugLocStream

There's no need to have more than one of these (there can be two
DwarfFiles - one for the .o, one for the .dwo - but only one loc/loclist
section (either in the .o or the .dwo) & certainly one per
DebugLocStream, which is currently singular in DwarfDebug)

llvm-svn: 375183

llvm/lib/CodeGen/AsmPrinter/DebugLocStream.h

@@ -49,6 +49,7 @@ private:
   SmallVector<Entry, 32> Entries;
   SmallString<256> DWARFBytes;
   std::vector<std::string> Comments;
+  MCSymbol *Sym;
 
   /// Only verbose textual output needs comments.  This will be set to
   /// true for that case, and false otherwise.
@@ -59,6 +60,12 @@ public:
   size_t getNumLists() const { return Lists.size(); }
   const List &getList(size_t LI) const { return Lists[LI]; }
   ArrayRef<List> getLists() const { return Lists; }
+  MCSymbol *getSym() const {
+    return Sym;
+  }
+  void setSym(MCSymbol *Sym) {
+    this->Sym = Sym;
+  }
 
   class ListBuilder;
   class EntryBuilder;

llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp

@@ -965,8 +965,6 @@ void DwarfDebug::beginModule() {
     DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
     Holder.setRnglistsTableBaseSym(
         Asm->createTempSymbol("rnglists_table_base"));
-    Holder.setLoclistsTableBaseSym(
-        Asm->createTempSymbol("loclists_table_base"));
 
     if (useSplitDwarf())
       InfoHolder.setRnglistsTableBaseSym(
@@ -1138,8 +1136,12 @@ void DwarfDebug::finalizeModuleInfo() {
       if (U.hasRangeLists())
         U.addRnglistsBase();
 
-      if (!DebugLocs.getLists().empty() && !useSplitDwarf())
-        U.addLoclistsBase();
+      if (!DebugLocs.getLists().empty() && !useSplitDwarf()) {
+        DebugLocs.setSym(Asm->createTempSymbol("loclists_table_base"));
+        U.addSectionLabel(U.getUnitDie(), dwarf::DW_AT_loclists_base,
+                          DebugLocs.getSym(),
+                          TLOF.getDwarfLoclistsSection()->getBeginSymbol());
+      }
     }
 
     auto *CUNode = cast<DICompileUnit>(P.first);
@@ -2304,16 +2306,18 @@ static MCSymbol *emitRnglistsTableHeader(AsmPrinter *Asm,
 // designates the end of the table for the caller to emit when the table is
 // complete.
 static MCSymbol *emitLoclistsTableHeader(AsmPrinter *Asm,
-                                         const DwarfFile &Holder) {
+                                         const DwarfDebug &DD) {
   MCSymbol *TableStart = Asm->createTempSymbol("debug_loclist_table_start");
   MCSymbol *TableEnd = Asm->createTempSymbol("debug_loclist_table_end");
   emitListsTableHeaderStart(Asm, TableStart, TableEnd);
 
+  const auto &DebugLocs = DD.getDebugLocs();
+
   // FIXME: Generate the offsets table and use DW_FORM_loclistx with the
   // DW_AT_loclists_base attribute. Until then set the number of offsets to 0.
   Asm->OutStreamer->AddComment("Offset entry count");
   Asm->emitInt32(0);
-  Asm->OutStreamer->EmitLabel(Holder.getLoclistsTableBaseSym());
+  Asm->OutStreamer->EmitLabel(DebugLocs.getSym());
 
   return TableEnd;
 }
@@ -2435,8 +2439,7 @@ void DwarfDebug::emitDebugLoc() {
   if (getDwarfVersion() >= 5) {
     Asm->OutStreamer->SwitchSection(
         Asm->getObjFileLowering().getDwarfLoclistsSection());
-    TableEnd = emitLoclistsTableHeader(Asm, useSplitDwarf() ? SkeletonHolder
-                                                            : InfoHolder);
+    TableEnd = emitLoclistsTableHeader(Asm, *this);
   } else {
     Asm->OutStreamer->SwitchSection(
         Asm->getObjFileLowering().getDwarfLocSection());

llvm/lib/CodeGen/AsmPrinter/DwarfFile.h

@@ -80,10 +80,6 @@ class DwarfFile {
   /// The table is shared by all units.
   MCSymbol *RnglistsTableBaseSym = nullptr;
 
-  /// DWARF v5: The symbol that designates the base of the locations list table.
-  /// The table is shared by all units.
-  MCSymbol *LoclistsTableBaseSym = nullptr;
-
   /// The variables of a lexical scope.
   struct ScopeVars {
     /// We need to sort Args by ArgNo and check for duplicates. This could also
@@ -161,9 +157,6 @@ public:
   MCSymbol *getRnglistsTableBaseSym() const { return RnglistsTableBaseSym; }
   void setRnglistsTableBaseSym(MCSymbol *Sym) { RnglistsTableBaseSym = Sym; }
 
-  MCSymbol *getLoclistsTableBaseSym() const { return LoclistsTableBaseSym; }
-  void setLoclistsTableBaseSym(MCSymbol *Sym) { LoclistsTableBaseSym = Sym; }
-
   /// \returns false if the variable was merged with a previous one.
   bool addScopeVariable(LexicalScope *LS, DbgVariable *Var);
 

llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp

@@ -1714,15 +1714,6 @@ void DwarfUnit::addRnglistsBase() {
                   TLOF.getDwarfRnglistsSection()->getBeginSymbol());
 }
 
-void DwarfUnit::addLoclistsBase() {
-  assert(DD->getDwarfVersion() >= 5 &&
-         "DW_AT_loclists_base requires DWARF version 5 or later");
-  const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
-  addSectionLabel(getUnitDie(), dwarf::DW_AT_loclists_base,
-                  DU->getLoclistsTableBaseSym(),
-                  TLOF.getDwarfLoclistsSection()->getBeginSymbol());
-}
-
 void DwarfTypeUnit::finishNonUnitTypeDIE(DIE& D, const DICompositeType *CTy) {
   addFlag(D, dwarf::DW_AT_declaration);
   StringRef Name = CTy->getName();

llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h

@@ -272,9 +272,6 @@ public:
   /// Add the DW_AT_rnglists_base attribute to the unit DIE.
   void addRnglistsBase();
 
-  /// Add the DW_AT_loclists_base attribute to the unit DIE.
-  void addLoclistsBase();
-
   virtual DwarfCompileUnit &getCU() = 0;
 
   void constructTypeDIE(DIE &Buffer, const DICompositeType *CTy);