AsmPrinter: Use an intrusively linked list for DIE::Children

Replace the `std::vector<>` for `DIE::Children` with an intrusively
linked list.  This is a strict memory improvement: it requires no
auxiliary storage, and reduces `sizeof(DIE)` by one pointer.  It also
factors out the DIE-related malloc traffic.

This drops llc memory usage from 735 MB down to 718 MB, or ~2.3%.

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

llvm-svn: 240736

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp
index de0ef33a9ed..ad180b6667c 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp
@@ -277,7 +277,7 @@ void AsmPrinter::emitDwarfDIE(const DIE &Die) const {
   // Emit the DIE children if any.
   if (Die.hasChildren()) {
     for (auto &Child : Die.children())
-      emitDwarfDIE(*Child);
+      emitDwarfDIE(Child);
 
     OutStreamer->AddComment("End Of Children Mark");
     EmitInt8(0);