[DwarfCompileUnit] getOrCreateCommonBlock(): check for existing entity first. NFCI

For global variables and common blocks there is no way to create entities
through getOrCreateContextDIE(), so no need to obtain the context first.

Differential Revision: https://reviews.llvm.org/D113651

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index b1d9c02..8c0a1f6 100644 (file)
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -349,12 +349,10 @@ void DwarfCompileUnit::addLocationAttribute(
 
 DIE *DwarfCompileUnit::getOrCreateCommonBlock(
     const DICommonBlock *CB, ArrayRef<GlobalExpr> GlobalExprs) {
-  // Construct the context before querying for the existence of the DIE in case
-  // such construction creates the DIE.
-  DIE *ContextDIE = getOrCreateContextDIE(CB->getScope());
-
+  // Check for pre-existence.
   if (DIE *NDie = getDIE(CB))
     return NDie;
+  DIE *ContextDIE = getOrCreateContextDIE(CB->getScope());
   DIE &NDie = createAndAddDIE(dwarf::DW_TAG_common_block, *ContextDIE, CB);
   StringRef Name = CB->getName().empty() ? "_BLNK_" : CB->getName();
   addString(NDie, dwarf::DW_AT_name, Name);