Do not emit empty DW_TAG_lexical_block DIEs. In one test case, size of debug info reduced by almost 7%.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126009 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 3c284bf..5106d57 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -1800,6 +1800,16 @@
if (!Scope || !Scope->getScopeNode())
return NULL;
+ SmallVector <DIE *, 8> Children;
+ // Collect lexical scope childrens first.
+ const SmallVector<DbgVariable *, 8> &Variables = Scope->getDbgVariables();
+ for (unsigned i = 0, N = Variables.size(); i < N; ++i)
+ if (DIE *Variable = constructVariableDIE(Variables[i], Scope))
+ Children.push_back(Variable);
+ const SmallVector<DbgScope *, 4> &Scopes = Scope->getScopes();
+ for (unsigned j = 0, M = Scopes.size(); j < M; ++j)
+ if (DIE *Nested = constructScopeDIE(Scopes[j]))
+ Children.push_back(Nested);
DIScope DS(Scope->getScopeNode());
DIE *ScopeDIE = NULL;
if (Scope->getInlinedAt())
@@ -1815,26 +1825,19 @@
else
ScopeDIE = updateSubprogramScopeDIE(DS);
}
- else
+ else {
+ // There is no need to emit empty lexical block DIE.
+ if (Children.empty())
+ return NULL;
ScopeDIE = constructLexicalScopeDIE(Scope);
+ }
+
if (!ScopeDIE) return NULL;
- // Add variables to scope.
- const SmallVector<DbgVariable *, 8> &Variables = Scope->getDbgVariables();
- for (unsigned i = 0, N = Variables.size(); i < N; ++i) {
- DIE *VariableDIE = constructVariableDIE(Variables[i], Scope);
- if (VariableDIE)
- ScopeDIE->addChild(VariableDIE);
- }
-
- // Add nested scopes.
- const SmallVector<DbgScope *, 4> &Scopes = Scope->getScopes();
- for (unsigned j = 0, M = Scopes.size(); j < M; ++j) {
- // Define the Scope debug information entry.
- DIE *NestedDIE = constructScopeDIE(Scopes[j]);
- if (NestedDIE)
- ScopeDIE->addChild(NestedDIE);
- }
+ // Add children
+ for (SmallVector<DIE *, 8>::iterator I = Children.begin(),
+ E = Children.end(); I != E; ++I)
+ ScopeDIE->addChild(*I);
if (DS.isSubprogram())
addPubTypes(DISubprogram(DS));