[llvm] r174084 - [Dwarf] early exit to avoid creating dangling DIEs

[Manman Ren]

Author: mren
Date: Thu Jan 31 14:05:14 2013
New Revision: 174084

URL: http://llvm.org/viewvc/llvm-project?rev=174084&view=rev
Log:
[Dwarf] early exit to avoid creating dangling DIEs

We used to create children DIEs for a scope, then check whether ScopeDIE is
null. If ScopeDIE is null, the children DIEs will be dangling. Other DIEs can
link to those dangling DIEs, which are not emitted at all, causing dwarf error.

The current testing case is 4k lines, from MultiSource/BenchMark/McCat/09-vor.

rdar://problem/13071959

Modified:
    llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp

Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp?rev=174084&r1=174083&r2=174084&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp Thu Jan 31 14:05:14 2013
@@ -540,6 +540,12 @@ DIE *DwarfDebug::constructScopeDIE(Compi
   if (!Scope || !Scope->getScopeNode())
     return NULL;
 
+  DIScope DS(Scope->getScopeNode());
+  // Early return to avoid creating dangling variable|scope DIEs.
+  if (!Scope->getInlinedAt() && DS.isSubprogram() && Scope->isAbstractScope() &&
+      !TheCU->getDIE(DS))
+    return NULL;
+
   SmallVector<DIE *, 8> Children;
   DIE *ObjectPointer = NULL;
 
@@ -565,7 +571,6 @@ DIE *DwarfDebug::constructScopeDIE(Compi
   for (unsigned j = 0, M = Scopes.size(); j < M; ++j)
     if (DIE *Nested = constructScopeDIE(TheCU, Scopes[j]))
       Children.push_back(Nested);
-  DIScope DS(Scope->getScopeNode());
   DIE *ScopeDIE = NULL;
   if (Scope->getInlinedAt())
     ScopeDIE = constructInlinedScopeDIE(TheCU, Scope);