[llvm] Non-functional change: declared a couple of local variables as const.

[dblaikie]

llvm/include/llvm/MC/MCContext.h

528

This doesn't immediately make sense to me - 'find' probably (I haven't double checked the type of MCDwarfLineTablesCUMap to confirm this, but find on most containers works this way) returns an iterator by value. Binding that to a reference is a bit surprising/confusing/unnecessary (& relies on reference lifetime extension - a rarely used/subtle feature)

So probably don't make this change.

llvm/lib/MC/MCAsmStreamer.cpp

1914

Seems reasonable

[tamur]

Reverted changes to llvm/MC/MCContext.h

[dblaikie]

Looks good - thanks!

llvm/include/llvm/MC/MCContext.h

const std::map<unsigned, MCDwarfLineTable> &getMCDwarfLineTables() const {
       return MCDwarfLineTablesCUMap;
     }
 
     MCDwarfLineTable &getMCDwarfLineTable(unsigned CUID) {
       return MCDwarfLineTablesCUMap[CUID];
     }
 
     const MCDwarfLineTable &getMCDwarfLineTable(unsigned CUID) const {
-      auto I = MCDwarfLineTablesCUMap.find(CUID);
+      const auto &I = MCDwarfLineTablesCUMap.find(CUID);
       assert(I != MCDwarfLineTablesCUMap.end());
       return I->second;
     }
 
     const SmallVectorImpl<MCDwarfFile> &getMCDwarfFiles(unsigned CUID = 0) {
       return getMCDwarfLineTable(CUID).getMCDwarfFiles();
     }
 

llvm/lib/MC/MCAsmStreamer.cpp

 void MCAsmStreamer::FinishImpl() {
   // If we are generating dwarf for assembly source files dump out the sections.
   if (getContext().getGenDwarfForAssembly())
     MCGenDwarfInfo::Emit(this);
 
   // Emit the label for the line table, if requested - since the rest of the
   // line table will be defined by .loc/.file directives, and not emitted
   // directly, the label is the only work required here.
-  auto &Tables = getContext().getMCDwarfLineTables();
+  const auto &Tables = getContext().getMCDwarfLineTables();
   if (!Tables.empty()) {
     assert(Tables.size() == 1 && "asm output only supports one line table");
     if (auto *Label = Tables.begin()->second.getLabel()) {
       SwitchSection(getContext().getObjectFileInfo()->getDwarfLineSection());
       EmitLabel(Label);
     }
   }
 }