[llvm] r223201 - ADT: Add SmallVector<>::emplace_back()

Duncan P. N. Exon Smith dexonsmith at apple.com
Tue Dec 2 20:45:09 PST 2014


Author: dexonsmith
Date: Tue Dec  2 22:45:09 2014
New Revision: 223201

URL: http://llvm.org/viewvc/llvm-project?rev=223201&view=rev
Log:
ADT: Add SmallVector<>::emplace_back()

Modified:
    llvm/trunk/include/llvm/ADT/SmallVector.h
    llvm/trunk/unittests/ADT/SmallVectorTest.cpp

Modified: llvm/trunk/include/llvm/ADT/SmallVector.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/SmallVector.h?rev=223201&r1=223200&r2=223201&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ADT/SmallVector.h (original)
+++ llvm/trunk/include/llvm/ADT/SmallVector.h Tue Dec  2 22:45:09 2014
@@ -236,6 +236,51 @@ public:
     this->setEnd(this->end()-1);
     this->end()->~T();
   }
+
+#if LLVM_HAS_VARIADIC_TEMPLATES
+  template <typename... ArgTypes> void emplace_back(ArgTypes &&... Args) {
+    if (LLVM_UNLIKELY(this->EndX >= this->CapacityX))
+      this->grow();
+    ::new ((void *)this->end()) T(std::forward<ArgTypes>(Args)...);
+    this->setEnd(this->end() + 1);
+  }
+#else
+private:
+  template <typename Constructor> emplace_back_impl(Constructor emplace) {
+    if (LLVM_UNLIKELY(this->EndX >= this->CapacityX))
+      this->grow();
+    emplace((void *)this->end());
+    this->setEnd(this->end() + 1);
+  }
+
+public:
+  void emplace_back() {
+    emplace_back_impl([](void *Mem) { ::new (Mem) T(); });
+  }
+  template <typename T1> void emplace_back(T1 &&A1) {
+    emplace_back_impl([&](void *Mem) { ::new (Mem) T(std::forward<T1>(A1)); });
+  }
+  template <typename T1, typename T2> void emplace_back(T1 &&A1, T2 &&A2) {
+    emplace_back_impl([&](void *Mem) {
+      ::new (Mem) T(std::forward<T1>(A1), std::forward<T2>(A2));
+    });
+  }
+  template <typename T1, typename T2, typename T3>
+  void emplace_back(T1 &&A1, T2 &&A2, T3 &&A3) {
+    T(std::forward<T1>(A1), std::forward<T2>(A2), std::forward<T3>(A3));
+    emplace_back_impl([&](void *Mem) {
+      ::new (Mem)
+          T(std::forward<T1>(A1), std::forward<T2>(A2), std::forward<T3>(A3));
+    });
+  }
+  template <typename T1, typename T2, typename T3, typename T4>
+  void emplace_back(T1 &&A1, T2 &&A2, T3 &&A3, T4 &&A4) {
+    emplace_back_impl([&](void *Mem) {
+      ::new (Mem) T(std::forward<T1>(A1), std::forward<T2>(A2),
+                    std::forward<T3>(A3), std::forward<T4>(A4));
+    });
+  }
+#endif // LLVM_HAS_VARIADIC_TEMPLATES
 };
 
 // Define this out-of-line to dissuade the C++ compiler from inlining it.

Modified: llvm/trunk/unittests/ADT/SmallVectorTest.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/ADT/SmallVectorTest.cpp?rev=223201&r1=223200&r2=223201&view=diff
==============================================================================
--- llvm/trunk/unittests/ADT/SmallVectorTest.cpp (original)
+++ llvm/trunk/unittests/ADT/SmallVectorTest.cpp Tue Dec  2 22:45:09 2014
@@ -699,4 +699,135 @@ TEST(SmallVectorTest, MidInsert) {
     EXPECT_TRUE(m.hasValue);
 }
 
+enum EmplaceableArgState {
+  EAS_Defaulted,
+  EAS_Arg,
+  EAS_LValue,
+  EAS_RValue,
+  EAS_Failure
+};
+template <int I> struct EmplaceableArg {
+  EmplaceableArgState State;
+  EmplaceableArg() : State(EAS_Defaulted) {}
+  EmplaceableArg(EmplaceableArg &&X)
+      : State(X.State == EAS_Arg ? EAS_RValue : EAS_Failure) {}
+  EmplaceableArg(EmplaceableArg &X)
+      : State(X.State == EAS_Arg ? EAS_LValue : EAS_Failure) {}
+
+  explicit EmplaceableArg(bool) : State(EAS_Arg) {}
+
+private:
+  EmplaceableArg(const EmplaceableArg &X) LLVM_DELETED_FUNCTION;
+  EmplaceableArg &operator=(EmplaceableArg &&) LLVM_DELETED_FUNCTION;
+  EmplaceableArg &operator=(const EmplaceableArg &) LLVM_DELETED_FUNCTION;
+};
+
+enum EmplaceableState { ES_Emplaced, ES_Moved };
+struct Emplaceable {
+  EmplaceableArg<0> A0;
+  EmplaceableArg<1> A1;
+  EmplaceableArg<2> A2;
+  EmplaceableArg<3> A3;
+  EmplaceableState State;
+
+  Emplaceable() : State(ES_Emplaced) {}
+
+  template <class A0Ty>
+  explicit Emplaceable(A0Ty &&A0)
+      : A0(std::forward<A0Ty>(A0)), State(ES_Emplaced) {}
+
+  template <class A0Ty, class A1Ty>
+  Emplaceable(A0Ty &&A0, A1Ty &&A1)
+      : A0(std::forward<A0Ty>(A0)), A1(std::forward<A1Ty>(A1)),
+        State(ES_Emplaced) {}
+
+  template <class A0Ty, class A1Ty, class A2Ty>
+  Emplaceable(A0Ty &&A0, A1Ty &&A1, A2Ty &&A2)
+      : A0(std::forward<A0Ty>(A0)), A1(std::forward<A1Ty>(A1)),
+        A2(std::forward<A2Ty>(A2)), State(ES_Emplaced) {}
+
+  template <class A0Ty, class A1Ty, class A2Ty, class A3Ty>
+  Emplaceable(A0Ty &&A0, A1Ty &&A1, A2Ty &&A2, A3Ty &&A3)
+      : A0(std::forward<A0Ty>(A0)), A1(std::forward<A1Ty>(A1)),
+        A2(std::forward<A2Ty>(A2)), A3(std::forward<A3Ty>(A3)),
+        State(ES_Emplaced) {}
+
+  Emplaceable(Emplaceable &&) : State(ES_Moved) {}
+  Emplaceable &operator=(Emplaceable &&) {
+    State = ES_Moved;
+    return *this;
+  }
+
+private:
+  Emplaceable(const Emplaceable &) LLVM_DELETED_FUNCTION;
+  Emplaceable &operator=(const Emplaceable &) LLVM_DELETED_FUNCTION;
+};
+
+TEST(SmallVectorTest, EmplaceBack) {
+  EmplaceableArg<0> A0(true);
+  EmplaceableArg<1> A1(true);
+  EmplaceableArg<2> A2(true);
+  EmplaceableArg<3> A3(true);
+  {
+    SmallVector<Emplaceable, 3> V;
+    V.emplace_back();
+    EXPECT_TRUE(V.size() == 1);
+    EXPECT_TRUE(V.back().State == ES_Emplaced);
+    EXPECT_TRUE(V.back().A0.State == EAS_Defaulted);
+    EXPECT_TRUE(V.back().A1.State == EAS_Defaulted);
+    EXPECT_TRUE(V.back().A2.State == EAS_Defaulted);
+    EXPECT_TRUE(V.back().A3.State == EAS_Defaulted);
+  }
+  {
+    SmallVector<Emplaceable, 3> V;
+    V.emplace_back(std::move(A0));
+    EXPECT_TRUE(V.size() == 1);
+    EXPECT_TRUE(V.back().State == ES_Emplaced);
+    EXPECT_TRUE(V.back().A0.State == EAS_RValue);
+    EXPECT_TRUE(V.back().A1.State == EAS_Defaulted);
+    EXPECT_TRUE(V.back().A2.State == EAS_Defaulted);
+    EXPECT_TRUE(V.back().A3.State == EAS_Defaulted);
+  }
+  {
+    SmallVector<Emplaceable, 3> V;
+    V.emplace_back(A0);
+    EXPECT_TRUE(V.size() == 1);
+    EXPECT_TRUE(V.back().State == ES_Emplaced);
+    EXPECT_TRUE(V.back().A0.State == EAS_LValue);
+    EXPECT_TRUE(V.back().A1.State == EAS_Defaulted);
+    EXPECT_TRUE(V.back().A2.State == EAS_Defaulted);
+    EXPECT_TRUE(V.back().A3.State == EAS_Defaulted);
+  }
+  {
+    SmallVector<Emplaceable, 3> V;
+    V.emplace_back(A0, A1);
+    EXPECT_TRUE(V.size() == 1);
+    EXPECT_TRUE(V.back().State == ES_Emplaced);
+    EXPECT_TRUE(V.back().A0.State == EAS_LValue);
+    EXPECT_TRUE(V.back().A1.State == EAS_LValue);
+    EXPECT_TRUE(V.back().A2.State == EAS_Defaulted);
+    EXPECT_TRUE(V.back().A3.State == EAS_Defaulted);
+  }
+  {
+    SmallVector<Emplaceable, 3> V;
+    V.emplace_back(std::move(A0), std::move(A1));
+    EXPECT_TRUE(V.size() == 1);
+    EXPECT_TRUE(V.back().State == ES_Emplaced);
+    EXPECT_TRUE(V.back().A0.State == EAS_RValue);
+    EXPECT_TRUE(V.back().A1.State == EAS_RValue);
+    EXPECT_TRUE(V.back().A2.State == EAS_Defaulted);
+    EXPECT_TRUE(V.back().A3.State == EAS_Defaulted);
+  }
+  {
+    SmallVector<Emplaceable, 3> V;
+    V.emplace_back(std::move(A0), A1, std::move(A2), A3);
+    EXPECT_TRUE(V.size() == 1);
+    EXPECT_TRUE(V.back().State == ES_Emplaced);
+    EXPECT_TRUE(V.back().A0.State == EAS_RValue);
+    EXPECT_TRUE(V.back().A1.State == EAS_LValue);
+    EXPECT_TRUE(V.back().A2.State == EAS_RValue);
+    EXPECT_TRUE(V.back().A3.State == EAS_LValue);
+  }
 }
+
+} // end namespace





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