DebugInfo: Remove some extra handling of abstract variables and instead rely solely on the delayed handling introduced in r210946

Now that we handle finding abstract variables at the end of the module,
remove the upfront handling and just ensure the abstract variable is
built when necessary.

In theory we could have a split implementation, where inlined variables
are immediately constructed referencing the abstract definition, and
concrete variables are delayed - but let's go with one solution for now
unless there's a reason not to.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210961 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 34 insertions, 40 deletions

diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 77bb77d4a5..2269686d2e 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -865,7 +865,7 @@ void DwarfDebug::collectDeadVariables() {
         for (unsigned vi = 0, ve = Variables.getNumElements(); vi != ve; ++vi) {
           DIVariable DV(Variables.getElement(vi));
           assert(DV.isVariable());
-          DbgVariable NewVar(DV, nullptr, this);
+          DbgVariable NewVar(DV, this);
           auto VariableDie = SPCU->constructVariableDIE(NewVar);
           SPCU->applyVariableAttributes(NewVar, *VariableDie);
           SPDIE->addChild(std::move(VariableDie));
@@ -1086,32 +1086,31 @@ DbgVariable *DwarfDebug::getExistingAbstractVariable(const DIVariable &DV) {
   return getExistingAbstractVariable(DV, Cleansed);
 }
 
-DbgVariable *DwarfDebug::createAbstractVariable(DIVariable &Var,
-                                                LexicalScope *Scope) {
-  auto AbsDbgVariable = make_unique<DbgVariable>(Var, nullptr, this);
+void DwarfDebug::createAbstractVariable(const DIVariable &Var,
+                                        LexicalScope *Scope) {
+  auto AbsDbgVariable = make_unique<DbgVariable>(Var, this);
   addScopeVariable(Scope, AbsDbgVariable.get());
-  return (AbstractVariables[Var] = std::move(AbsDbgVariable)).get();
+  AbstractVariables[Var] = std::move(AbsDbgVariable);
 }
 
-DbgVariable *DwarfDebug::getOrCreateAbstractVariable(DIVariable &DV,
-                                                     const MDNode *ScopeNode) {
+void DwarfDebug::ensureAbstractVariableIsCreated(const DIVariable &DV,
+                                                 const MDNode *ScopeNode) {
   DIVariable Cleansed = DV;
-  if (DbgVariable *Var = getExistingAbstractVariable(DV, Cleansed))
-    return Var;
+  if (getExistingAbstractVariable(DV, Cleansed))
+    return;
 
-  return createAbstractVariable(Cleansed,
-                                LScopes.getOrCreateAbstractScope(ScopeNode));
+  createAbstractVariable(Cleansed, LScopes.getOrCreateAbstractScope(ScopeNode));
 }
 
-DbgVariable *DwarfDebug::findAbstractVariable(DIVariable &DV,
-                                              const MDNode *ScopeNode) {
+void
+DwarfDebug::ensureAbstractVariableIsCreatedIfScoped(const DIVariable &DV,
+                                                    const MDNode *ScopeNode) {
   DIVariable Cleansed = DV;
-  if (DbgVariable *Var = getExistingAbstractVariable(DV, Cleansed))
-    return Var;
+  if (getExistingAbstractVariable(DV, Cleansed))
+    return;
 
   if (LexicalScope *Scope = LScopes.findAbstractScope(ScopeNode))
-    return createAbstractVariable(Cleansed, Scope);
-  return nullptr;
+    createAbstractVariable(Cleansed, Scope);
 }
 
 // If Var is a current function argument then add it to CurrentFnArguments list.
@@ -1150,9 +1149,8 @@ void DwarfDebug::collectVariableInfoFromMMITable(
     if (!Scope)
       continue;
 
-    DbgVariable *AbsDbgVariable =
-        findAbstractVariable(DV, Scope->getScopeNode());
-    ConcreteVariables.push_back(make_unique<DbgVariable>(DV, AbsDbgVariable, this));
+    ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
+    ConcreteVariables.push_back(make_unique<DbgVariable>(DV, this));
     DbgVariable *RegVar = ConcreteVariables.back().get();
     RegVar->setFrameIndex(VI.Slot);
     addScopeVariable(Scope, RegVar);
@@ -1220,8 +1218,8 @@ DwarfDebug::collectVariableInfo(SmallPtrSet<const MDNode *, 16> &Processed) {
     Processed.insert(DV);
     const MachineInstr *MInsn = Ranges.front().first;
     assert(MInsn->isDebugValue() && "History must begin with debug value");
-    DbgVariable *AbsVar = findAbstractVariable(DV, Scope->getScopeNode());
-    ConcreteVariables.push_back(make_unique<DbgVariable>(MInsn, AbsVar, this));
+    ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
+    ConcreteVariables.push_back(make_unique<DbgVariable>(MInsn, this));
     DbgVariable *RegVar = ConcreteVariables.back().get();
     addScopeVariable(Scope, RegVar);
 
@@ -1278,8 +1276,8 @@ DwarfDebug::collectVariableInfo(SmallPtrSet<const MDNode *, 16> &Processed) {
     if (!Processed.insert(DV))
       continue;
     if (LexicalScope *Scope = LScopes.findLexicalScope(DV.getContext())) {
-      ConcreteVariables.push_back(make_unique<DbgVariable>(
-          DV, findAbstractVariable(DV, Scope->getScopeNode()), this));
+      ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
+      ConcreteVariables.push_back(make_unique<DbgVariable>(DV, this));
       addScopeVariable(Scope, ConcreteVariables.back().get());
     }
   }
@@ -1563,7 +1561,7 @@ void DwarfDebug::endFunction(const MachineFunction *MF) {
       assert(DV && DV.isVariable());
       if (!ProcessedVars.insert(DV))
         continue;
-      getOrCreateAbstractVariable(DV, DV.getContext());
+      ensureAbstractVariableIsCreated(DV, DV.getContext());
     }
     constructAbstractSubprogramScopeDIE(TheCU, AScope);
   }
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.h b/lib/CodeGen/AsmPrinter/DwarfDebug.h
index 8445b74798..f2aa80845a 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -72,25 +72,21 @@ class DbgVariable {
   DIVariable Var;             // Variable Descriptor.
   DIE *TheDIE;                // Variable DIE.
   unsigned DotDebugLocOffset; // Offset in DotDebugLocEntries.
-  DbgVariable *AbsVar;        // Corresponding Abstract variable, if any.
   const MachineInstr *MInsn;  // DBG_VALUE instruction of the variable.
   int FrameIndex;
   DwarfDebug *DD;
 
 public:
   /// Construct a DbgVariable from a DIVariable.
-  /// AbstractVar may be NULL.
-  DbgVariable(DIVariable V, DbgVariable *AbstractVar, DwarfDebug *DD)
-      : Var(V), TheDIE(nullptr), DotDebugLocOffset(~0U), AbsVar(AbstractVar),
-        MInsn(nullptr), FrameIndex(~0), DD(DD) {}
+  DbgVariable(DIVariable V, DwarfDebug *DD)
+      : Var(V), TheDIE(nullptr), DotDebugLocOffset(~0U), MInsn(nullptr),
+        FrameIndex(~0), DD(DD) {}
 
   /// Construct a DbgVariable from a DEBUG_VALUE.
   /// AbstractVar may be NULL.
-  DbgVariable(const MachineInstr *DbgValue, DbgVariable *AbstractVar,
-              DwarfDebug *DD)
-    : Var(DbgValue->getDebugVariable()),
-      TheDIE(nullptr), DotDebugLocOffset(~0U), AbsVar(AbstractVar),
-      MInsn(DbgValue), FrameIndex(~0), DD(DD) {}
+  DbgVariable(const MachineInstr *DbgValue, DwarfDebug *DD)
+      : Var(DbgValue->getDebugVariable()), TheDIE(nullptr),
+        DotDebugLocOffset(~0U), MInsn(DbgValue), FrameIndex(~0), DD(DD) {}
 
   // Accessors.
   DIVariable getVariable() const { return Var; }
@@ -99,7 +95,6 @@ public:
   void setDotDebugLocOffset(unsigned O) { DotDebugLocOffset = O; }
   unsigned getDotDebugLocOffset() const { return DotDebugLocOffset; }
   StringRef getName() const { return Var.getName(); }
-  DbgVariable *getAbstractVariable() const { return AbsVar; }
   const MachineInstr *getMInsn() const { return MInsn; }
   int getFrameIndex() const { return FrameIndex; }
   void setFrameIndex(int FI) { FrameIndex = FI; }
@@ -347,10 +342,11 @@ class DwarfDebug : public AsmPrinterHandler {
   DbgVariable *getExistingAbstractVariable(const DIVariable &DV,
                                            DIVariable &Cleansed);
   DbgVariable *getExistingAbstractVariable(const DIVariable &DV);
-  DbgVariable *createAbstractVariable(DIVariable &DV, LexicalScope *Scope);
-  DbgVariable *getOrCreateAbstractVariable(DIVariable &Var,
-                                           const MDNode *Scope);
-  DbgVariable *findAbstractVariable(DIVariable &Var, const MDNode *Scope);
+  void createAbstractVariable(const DIVariable &DV, LexicalScope *Scope);
+  void ensureAbstractVariableIsCreated(const DIVariable &Var,
+                                       const MDNode *Scope);
+  void ensureAbstractVariableIsCreatedIfScoped(const DIVariable &Var,
+                                               const MDNode *Scope);
 
   /// \brief Find DIE for the given subprogram and attach appropriate
   /// DW_AT_low_pc and DW_AT_high_pc attributes. If there are global