AsmPrinter: Avoid creating symbols in DwarfStringPool

Stop creating symbols we don't need in `DwarfStringPool`.  The consumers
only call `DwarfStringPoolEntryRef::getSymbol()` when DWARF is
relocatable, so this just stops creating the unused symbols when it's
not.  This drops memory usage from 851 MB to 845 MB, around 0.7%.

(I'm looking at `llc` memory usage on `verify-uselistorder.lto.opt.bc`;
see r236629 for details.)

llvm-svn: 238122

1 files changed, 2 insertions, 2 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfStringPool.h b/llvm/lib/CodeGen/AsmPrinter/DwarfStringPool.h
index b042350fb59..93a168485a5 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfStringPool.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfStringPool.h
@@ -30,12 +30,12 @@ class DwarfStringPool {
   StringMap<EntryTy, BumpPtrAllocator &> Pool;
   StringRef Prefix;
   unsigned NumBytes = 0;
+  bool ShouldCreateSymbols;
 
 public:
   typedef DwarfStringPoolEntryRef EntryRef;
 
-  DwarfStringPool(BumpPtrAllocator &A, AsmPrinter &Asm, StringRef Prefix)
-      : Pool(A), Prefix(Prefix) {}
+  DwarfStringPool(BumpPtrAllocator &A, AsmPrinter &Asm, StringRef Prefix);
 
   void emit(AsmPrinter &Asm, MCSection *StrSection,
             MCSection *OffsetSection = nullptr);