Refactor overridden methods iteration to avoid double lookups.

Convert most uses to range-for loops. No functionality change intended.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@320954 91177308-0d34-0410-b5e6-96231b3b80d8

14 files changed, 52 insertions, 88 deletions

diff --git a/include/clang/AST/DeclCXX.h b/include/clang/AST/DeclCXX.h
index a8bc68a004..88dc9a6559 100644
--- a/include/clang/AST/DeclCXX.h
+++ b/include/clang/AST/DeclCXX.h
@@ -2015,7 +2015,7 @@ public:
     if (CD->isVirtualAsWritten() || CD->isPure())
       return true;
 
-    return (CD->begin_overridden_methods() != CD->end_overridden_methods());
+    return CD->size_overridden_methods() != 0;
   }
 
   /// If it's possible to devirtualize a call to this method, return the called
diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index 34a925020e..dd96148edb 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -1378,35 +1378,27 @@ void ASTContext::setInstantiatedFromUnnamedFieldDecl(FieldDecl *Inst,
 
 ASTContext::overridden_cxx_method_iterator
 ASTContext::overridden_methods_begin(const CXXMethodDecl *Method) const {
-  llvm::DenseMap<const CXXMethodDecl *, CXXMethodVector>::const_iterator Pos =
-      OverriddenMethods.find(Method->getCanonicalDecl());
-  if (Pos == OverriddenMethods.end())
-    return nullptr;
-  return Pos->second.begin();
+  return overridden_methods(Method).begin();
 }
 
 ASTContext::overridden_cxx_method_iterator
 ASTContext::overridden_methods_end(const CXXMethodDecl *Method) const {
-  llvm::DenseMap<const CXXMethodDecl *, CXXMethodVector>::const_iterator Pos =
-      OverriddenMethods.find(Method->getCanonicalDecl());
-  if (Pos == OverriddenMethods.end())
-    return nullptr;
-  return Pos->second.end();
+  return overridden_methods(Method).end();
 }
 
 unsigned
 ASTContext::overridden_methods_size(const CXXMethodDecl *Method) const {
-  llvm::DenseMap<const CXXMethodDecl *, CXXMethodVector>::const_iterator Pos =
-      OverriddenMethods.find(Method->getCanonicalDecl());
-  if (Pos == OverriddenMethods.end())
-    return 0;
-  return Pos->second.size();
+  auto Range = overridden_methods(Method);
+  return Range.end() - Range.begin();
 }
 
 ASTContext::overridden_method_range
 ASTContext::overridden_methods(const CXXMethodDecl *Method) const {
-  return overridden_method_range(overridden_methods_begin(Method),
-                                 overridden_methods_end(Method));
+  llvm::DenseMap<const CXXMethodDecl *, CXXMethodVector>::const_iterator Pos =
+      OverriddenMethods.find(Method->getCanonicalDecl());
+  if (Pos == OverriddenMethods.end())
+    return overridden_method_range(nullptr, nullptr);
+  return overridden_method_range(Pos->second.begin(), Pos->second.end());
 }
 
 void ASTContext::addOverriddenMethod(const CXXMethodDecl *Method, 
diff --git a/lib/AST/ASTDumper.cpp b/lib/AST/ASTDumper.cpp
index e74aee0aaa..157b29fd84 100644
--- a/lib/AST/ASTDumper.cpp
+++ b/lib/AST/ASTDumper.cpp
@@ -1195,12 +1195,11 @@ void ASTDumper::VisitFunctionDecl(const FunctionDecl *D) {
         };
 
       dumpChild([=] {
-        auto FirstOverrideItr = MD->begin_overridden_methods();
+        auto Overrides = MD->overridden_methods();
         OS << "Overrides: [ ";
-        dumpOverride(*FirstOverrideItr);
+        dumpOverride(*Overrides.begin());
         for (const auto *Override :
-               llvm::make_range(FirstOverrideItr + 1,
-                                MD->end_overridden_methods())) {
+             llvm::make_range(Overrides.begin() + 1, Overrides.end())) {
           OS << ", ";
           dumpOverride(Override);
         }
diff --git a/lib/AST/CXXInheritance.cpp b/lib/AST/CXXInheritance.cpp
index 4f9f1da95f..24e96ba380 100644
--- a/lib/AST/CXXInheritance.cpp
+++ b/lib/AST/CXXInheritance.cpp
@@ -650,9 +650,11 @@ void FinalOverriderCollector::Collect(const CXXRecordDecl *RD,
       continue;
 
     CXXMethodDecl *CanonM = cast<CXXMethodDecl>(M->getCanonicalDecl());
+    using OverriddenMethodsRange =
+        llvm::iterator_range<CXXMethodDecl::method_iterator>;
+    OverriddenMethodsRange OverriddenMethods = CanonM->overridden_methods();
 
-    if (CanonM->begin_overridden_methods()
-                                       == CanonM->end_overridden_methods()) {
+    if (OverriddenMethods.begin() == OverriddenMethods.end()) {
       // This is a new virtual function that does not override any
       // other virtual function. Add it to the map of virtual
       // functions for which we are tracking overridders. 
@@ -671,11 +673,7 @@ void FinalOverriderCollector::Collect(const CXXRecordDecl *RD,
     // overrider. To do so, we dig down to the original virtual
     // functions using data recursion and update all of the methods it
     // overrides.
-    using OverriddenMethods =
-        llvm::iterator_range<CXXMethodDecl::method_iterator>;
-    SmallVector<OverriddenMethods, 4> Stack;
-    Stack.push_back(llvm::make_range(CanonM->begin_overridden_methods(),
-                                     CanonM->end_overridden_methods()));
+    SmallVector<OverriddenMethodsRange, 4> Stack(1, OverriddenMethods);
     while (!Stack.empty()) {
       for (const CXXMethodDecl *OM : Stack.pop_back_val()) {
         const CXXMethodDecl *CanonOM = OM->getCanonicalDecl();
@@ -693,14 +691,13 @@ void FinalOverriderCollector::Collect(const CXXRecordDecl *RD,
                                UniqueVirtualMethod(CanonM, SubobjectNumber,
                                                    InVirtualSubobject));
 
-        if (CanonOM->begin_overridden_methods()
-                                       == CanonOM->end_overridden_methods())
+        auto OverriddenMethods = CanonOM->overridden_methods();
+        if (OverriddenMethods.begin() == OverriddenMethods.end())
           continue;
 
         // Continue recursion to the methods that this virtual method
         // overrides.
-        Stack.push_back(llvm::make_range(CanonOM->begin_overridden_methods(),
-                                         CanonOM->end_overridden_methods()));
+        Stack.push_back(OverriddenMethods);
       }
     }
 
diff --git a/lib/AST/DeclCXX.cpp b/lib/AST/DeclCXX.cpp
index 6126cc5267..41f2449a9d 100644
--- a/lib/AST/DeclCXX.cpp
+++ b/lib/AST/DeclCXX.cpp
@@ -1642,9 +1642,7 @@ bool CXXMethodDecl::isStatic() const {
 
 static bool recursivelyOverrides(const CXXMethodDecl *DerivedMD,
                                  const CXXMethodDecl *BaseMD) {
-  for (CXXMethodDecl::method_iterator I = DerivedMD->begin_overridden_methods(),
-         E = DerivedMD->end_overridden_methods(); I != E; ++I) {
-    const CXXMethodDecl *MD = *I;
+  for (const CXXMethodDecl *MD : DerivedMD->overridden_methods()) {
     if (MD->getCanonicalDecl() == BaseMD->getCanonicalDecl())
       return true;
     if (recursivelyOverrides(MD, BaseMD))
diff --git a/lib/AST/RecordLayoutBuilder.cpp b/lib/AST/RecordLayoutBuilder.cpp
index 0083e390cb..a9d43dfa80 100644
--- a/lib/AST/RecordLayoutBuilder.cpp
+++ b/lib/AST/RecordLayoutBuilder.cpp
@@ -2895,13 +2895,12 @@ void MicrosoftRecordLayoutBuilder::computeVtorDispSet(
       Work.insert(MD);
   while (!Work.empty()) {
     const CXXMethodDecl *MD = *Work.begin();
-    CXXMethodDecl::method_iterator i = MD->begin_overridden_methods(),
-                                   e = MD->end_overridden_methods();
+    auto MethodRange = MD->overridden_methods();
     // If a virtual method has no-overrides it lives in its parent's vtable.
-    if (i == e)
+    if (MethodRange.begin() == MethodRange.end())
       BasesWithOverriddenMethods.insert(MD->getParent());
     else
-      Work.insert(i, e);
+      Work.insert(MethodRange.begin(), MethodRange.end());
     // We've finished processing this element, remove it from the working set.
     Work.erase(MD);
   }
diff --git a/lib/AST/VTableBuilder.cpp b/lib/AST/VTableBuilder.cpp
index ae8f6309fc..347c516ef6 100644
--- a/lib/AST/VTableBuilder.cpp
+++ b/lib/AST/VTableBuilder.cpp
@@ -1079,9 +1079,7 @@ static void
 visitAllOverriddenMethods(const CXXMethodDecl *MD, VisitorTy &Visitor) {
   assert(MD->isVirtual() && "Method is not virtual!");
 
-  for (CXXMethodDecl::method_iterator I = MD->begin_overridden_methods(),
-       E = MD->end_overridden_methods(); I != E; ++I) {
-    const CXXMethodDecl *OverriddenMD = *I;
+  for (const CXXMethodDecl *OverriddenMD : MD->overridden_methods()) {
     if (!Visitor(OverriddenMD))
       continue;
     visitAllOverriddenMethods(OverriddenMD, Visitor);
@@ -1329,11 +1327,8 @@ static bool OverridesIndirectMethodInBases(
     ItaniumVTableBuilder::PrimaryBasesSetVectorTy &Bases) {
   if (Bases.count(MD->getParent()))
     return true;
-  
-  for (CXXMethodDecl::method_iterator I = MD->begin_overridden_methods(),
-       E = MD->end_overridden_methods(); I != E; ++I) {
-    const CXXMethodDecl *OverriddenMD = *I;
-    
+
+  for (const CXXMethodDecl *OverriddenMD : MD->overridden_methods()) {
     // Check "indirect overriders".
     if (OverridesIndirectMethodInBases(OverriddenMD, Bases))
       return true;
diff --git a/lib/Analysis/ThreadSafetyCommon.cpp b/lib/Analysis/ThreadSafetyCommon.cpp
index c1421b09c9..99284f07b4 100644
--- a/lib/Analysis/ThreadSafetyCommon.cpp
+++ b/lib/Analysis/ThreadSafetyCommon.cpp
@@ -319,11 +319,11 @@ static bool hasCppPointerType(const til::SExpr *E) {
 static const CXXMethodDecl *getFirstVirtualDecl(const CXXMethodDecl *D) {
   while (true) {
     D = D->getCanonicalDecl();
-    CXXMethodDecl::method_iterator I = D->begin_overridden_methods(),
-                                   E = D->end_overridden_methods();
-    if (I == E)
+    auto OverriddenMethods = D->overridden_methods();
+    if (OverriddenMethods.begin() == OverriddenMethods.end())
       return D;  // Method does not override anything
-    D = *I;      // FIXME: this does not work with multiple inheritance.
+    // FIXME: this does not work with multiple inheritance.
+    D = *OverriddenMethods.begin();
   }
   return nullptr;
 }
diff --git a/lib/CodeGen/CGDebugInfo.cpp b/lib/CodeGen/CGDebugInfo.cpp
index 5a288abe36..caea41ec0e 100644
--- a/lib/CodeGen/CGDebugInfo.cpp
+++ b/lib/CodeGen/CGDebugInfo.cpp
@@ -1395,7 +1395,7 @@ llvm::DISubprogram *CGDebugInfo::CreateCXXMemberFunction(
       // C++ ABI does not include all virtual methods from non-primary bases in
       // the vtable for the most derived class. For example, if C inherits from
       // A and B, C's primary vftable will not include B's virtual methods.
-      if (Method->begin_overridden_methods() == Method->end_overridden_methods())
+      if (Method->size_overridden_methods() == 0)
         Flags |= llvm::DINode::FlagIntroducedVirtual;
 
       // The 'this' adjustment accounts for both the virtual and non-virtual
diff --git a/lib/Index/IndexDecl.cpp b/lib/Index/IndexDecl.cpp
index 0615aeacea..e14750e046 100644
--- a/lib/Index/IndexDecl.cpp
+++ b/lib/Index/IndexDecl.cpp
@@ -233,9 +233,8 @@ public:
     if (auto *CXXMD = dyn_cast<CXXMethodDecl>(D)) {
       if (CXXMD->isVirtual())
         Roles |= (unsigned)SymbolRole::Dynamic;
-      for (auto I = CXXMD->begin_overridden_methods(),
-           E = CXXMD->end_overridden_methods(); I != E; ++I) {
-        Relations.emplace_back((unsigned)SymbolRole::RelationOverrideOf, *I);
+      for (const CXXMethodDecl *O : CXXMD->overridden_methods()) {
+        Relations.emplace_back((unsigned)SymbolRole::RelationOverrideOf, O);
       }
     }
     gatherTemplatePseudoOverrides(D, Relations);
diff --git a/lib/Sema/SemaCodeComplete.cpp b/lib/Sema/SemaCodeComplete.cpp
index ee11c5c94e..834e149d1a 100644
--- a/lib/Sema/SemaCodeComplete.cpp
+++ b/lib/Sema/SemaCodeComplete.cpp
@@ -3378,12 +3378,9 @@ static void MaybeAddOverrideCalls(Sema &S, DeclContext *InContext,
       return;
 
   PrintingPolicy Policy = getCompletionPrintingPolicy(S);
-  for (CXXMethodDecl::method_iterator M = Method->begin_overridden_methods(),
-                                   MEnd = Method->end_overridden_methods();
-       M != MEnd; ++M) {
+  for (const CXXMethodDecl *Overridden : Method->overridden_methods()) {
     CodeCompletionBuilder Builder(Results.getAllocator(),
                                   Results.getCodeCompletionTUInfo());
-    const CXXMethodDecl *Overridden = *M;
     if (Overridden->getCanonicalDecl() == Method->getCanonicalDecl())
       continue;
         
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 0b48a87c11..ec5ca69735 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -7517,16 +7517,14 @@ enum OverrideErrorKind { OEK_All, OEK_NonDeleted, OEK_Deleted };
 static void ReportOverrides(Sema& S, unsigned DiagID, const CXXMethodDecl *MD,
                             OverrideErrorKind OEK = OEK_All) {
   S.Diag(MD->getLocation(), DiagID) << MD->getDeclName();
-  for (CXXMethodDecl::method_iterator I = MD->begin_overridden_methods(),
-                                      E = MD->end_overridden_methods();
-       I != E; ++I) {
+  for (const CXXMethodDecl *O : MD->overridden_methods()) {
     // This check (& the OEK parameter) could be replaced by a predicate, but
     // without lambdas that would be overkill. This is still nicer than writing
     // out the diag loop 3 times.
     if ((OEK == OEK_All) ||
-        (OEK == OEK_NonDeleted && !(*I)->isDeleted()) ||
-        (OEK == OEK_Deleted && (*I)->isDeleted()))
-      S.Diag((*I)->getLocation(), diag::note_overridden_virtual_function);
+        (OEK == OEK_NonDeleted && !O->isDeleted()) ||
+        (OEK == OEK_Deleted && O->isDeleted()))
+      S.Diag(O->getLocation(), diag::note_overridden_virtual_function);
   }
 }
 
diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index 497713f660..96472a0a70 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -2748,8 +2748,7 @@ void Sema::CheckOverrideControl(NamedDecl *D) {
   //   If a function is marked with the virt-specifier override and
   //   does not override a member function of a base class, the program is
   //   ill-formed.
-  bool HasOverriddenMethods =
-    MD->begin_overridden_methods() != MD->end_overridden_methods();
+  bool HasOverriddenMethods = MD->size_overridden_methods() != 0;
   if (MD->hasAttr<OverrideAttr>() && !HasOverriddenMethods)
     Diag(MD->getLocation(), diag::err_function_marked_override_not_overriding)
       << MD->getDeclName();
@@ -7424,10 +7423,8 @@ private:
       const llvm::SmallPtrSetImpl<const CXXMethodDecl *> &Methods) {
     if (MD->size_overridden_methods() == 0)
       return Methods.count(MD->getCanonicalDecl());
-    for (CXXMethodDecl::method_iterator I = MD->begin_overridden_methods(),
-                                        E = MD->end_overridden_methods();
-         I != E; ++I)
-      if (CheckMostOverridenMethods(*I, Methods))
+    for (const CXXMethodDecl *O : MD->overridden_methods())
+      if (CheckMostOverridenMethods(O, Methods))
         return true;
     return false;
   }
@@ -7485,10 +7482,9 @@ static void AddMostOverridenMethods(const CXXMethodDecl *MD,
                         llvm::SmallPtrSetImpl<const CXXMethodDecl *>& Methods) {
   if (MD->size_overridden_methods() == 0)
     Methods.insert(MD->getCanonicalDecl());
-  for (CXXMethodDecl::method_iterator I = MD->begin_overridden_methods(),
-                                      E = MD->end_overridden_methods();
-       I != E; ++I)
-    AddMostOverridenMethods(*I, Methods);
+  else
+    for (const CXXMethodDecl *O : MD->overridden_methods())
+      AddMostOverridenMethods(O, Methods);
 }
 
 /// \brief Check if a method overloads virtual methods in a base class without
@@ -14062,15 +14058,13 @@ void Sema::SetDeclDeleted(Decl *Dcl, SourceLocation DelLoc) {
   // non-deleted virtual function.
   if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Fn)) {
     bool IssuedDiagnostic = false;
-    for (CXXMethodDecl::method_iterator I = MD->begin_overridden_methods(),
-                                        E = MD->end_overridden_methods();
-         I != E; ++I) {
+    for (const CXXMethodDecl *O : MD->overridden_methods()) {
       if (!(*MD->begin_overridden_methods())->isDeleted()) {
         if (!IssuedDiagnostic) {
           Diag(DelLoc, diag::err_deleted_override) << MD->getDeclName();
           IssuedDiagnostic = true;
         }
-        Diag((*I)->getLocation(), diag::note_overridden_virtual_function);
+        Diag(O->getLocation(), diag::note_overridden_virtual_function);
       }
     }
     // If this function was implicitly deleted because it was defaulted,
@@ -14981,10 +14975,8 @@ void Sema::actOnDelayedExceptionSpecification(Decl *MethodD,
 
   if (Method->isVirtual()) {
     // Check overrides, which we previously had to delay.
-    for (CXXMethodDecl::method_iterator O = Method->begin_overridden_methods(),
-                                     OEnd = Method->end_overridden_methods();
-         O != OEnd; ++O)
-      CheckOverridingFunctionExceptionSpec(Method, *O);
+    for (const CXXMethodDecl *O : Method->overridden_methods())
+      CheckOverridingFunctionExceptionSpec(Method, O);
   }
 }
 
diff --git a/lib/Serialization/ASTWriterDecl.cpp b/lib/Serialization/ASTWriterDecl.cpp
index 041ccd47d0..3dac3a4829 100644
--- a/lib/Serialization/ASTWriterDecl.cpp
+++ b/lib/Serialization/ASTWriterDecl.cpp
@@ -1267,10 +1267,8 @@ void ASTDeclWriter::VisitCXXMethodDecl(CXXMethodDecl *D) {
   VisitFunctionDecl(D);
   if (D->isCanonicalDecl()) {
     Record.push_back(D->size_overridden_methods());
-    for (CXXMethodDecl::method_iterator
-           I = D->begin_overridden_methods(), E = D->end_overridden_methods();
-           I != E; ++I)
-      Record.AddDeclRef(*I);
+    for (const CXXMethodDecl *MD : D->overridden_methods())
+      Record.AddDeclRef(MD);
   } else {
     // We only need to record overridden methods once for the canonical decl.
     Record.push_back(0);