Debug Info: create scope children DIEs when the scope DIE is not null.

We try to create the scope children DIEs after we create the scope DIE. But
to avoid emitting empty lexical block DIE, we first check whether a scope
DIE is going to be null, then create the scope children if it is not null.
From the number of children, we decide whether to actually create the scope DIE.

This patch also removes an early exit which checks for a special condition.
It also removes deletion of un-used children DIEs that are generated
because we used to generate children DIEs before the scope DIE.

Deletion of un-used children DIEs may cause problem because we sometimes keep
created DIEs in a member variable of a CU.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190421 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 6 insertions, 0 deletions

diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.h b/lib/CodeGen/AsmPrinter/DwarfDebug.h
index 6c13b9ec6f..c702180dc3 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -469,6 +469,9 @@ private:
   /// \brief Construct new DW_TAG_lexical_block for this scope and
   /// attach DW_AT_low_pc/DW_AT_high_pc labels.
   DIE *constructLexicalScopeDIE(CompileUnit *TheCU, LexicalScope *Scope);
+  /// A helper function to check whether the DIE for a given Scope is going
+  /// to be null.
+  bool isLexicalScopeDIENull(LexicalScope *Scope);
 
   /// \brief This scope represents inlined body of a function. Construct
   /// DIE to represent this concrete inlined copy of the function.
@@ -476,6 +479,9 @@ private:
 
   /// \brief Construct a DIE for this scope.
   DIE *constructScopeDIE(CompileUnit *TheCU, LexicalScope *Scope);
+  /// A helper function to create children of a Scope DIE.
+  DIE *createScopeChildrenDIE(CompileUnit *TheCU, LexicalScope *Scope,
+                              SmallVectorImpl<DIE*> &Children);
 
   /// \brief Emit initial Dwarf sections with a label at the start of each one.
   void emitSectionLabels();