[DWARF] Defer creating declaration DIEs until we prepare call site info

It isn't necessary to create DIEs for all of the declaration subprograms
in a CU's retainedTypes list. We can defer creating these subprograms
until we need to prepare a call site tag that refers to one.

This cleanup was mentioned in passing in D70350.

1 files changed, 0 insertions, 7 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index d1a36299dc4..624e1a513ec 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -924,13 +924,6 @@ DwarfDebug::getOrCreateDwarfCompileUnit(const DICompileUnit *DIUnit) {
     NewCU.setSection(Asm->getObjFileLowering().getDwarfInfoSection());
   }
 
-  // Create DIEs for function declarations used for call site debug info.
-  // Note: Declaration subprograms imported by LTO are not added to the unit's
-  // list of retained types, so their DIEs are not constructed here.
-  for (auto Scope : DIUnit->getRetainedTypes())
-    if (auto *SP = dyn_cast_or_null<DISubprogram>(Scope))
-      NewCU.getOrCreateSubprogramDIE(SP);
-
   CUMap.insert({DIUnit, &NewCU});
   CUDieMap.insert({&NewCU.getUnitDie(), &NewCU});
   return NewCU;