add nrvo_by_default/

3 files changed, 120 insertions, 0 deletions

diff --git a/nrvo_by_default/Makefile b/nrvo_by_default/Makefile
new file mode 100644
index 0000000..f9fd487
--- /dev/null
+++ b/nrvo_by_default/Makefile
@@ -0,0 +1,26 @@
+# Builds rvo.cpp on various optimization levels supported by GCC.
+# The compiler is `g++` by default.
+# You can change the compiler to be used using the CXX variable.
+# For example, if you want to compile using `x86_64-w64-mingw32-g++`, run
+#
+#     > make CXX=x86_64-w64-mingw32-g++
+
+CXXFLAGS = -Wall -Wextra -DNDEBUG -std=c++11 -static-libgcc -static-libstdc++ -s
+
+optimization_levels = 0 1 2 3
+
+all::
+
+define make_target
+rvo.$(CXX).O$(1).exe: rvo.cpp
+	$(CXX) $(CXXFLAGS) -O$(1) $$< -o $$@
+
+all:: rvo.$(CXX).O$(1).exe
+endef
+
+$(foreach i,$(optimization_levels),$(eval $(call make_target,$(i))))
+
+.PHONY: clean-all
+
+clean-all:
+	$(RM) $(wildcard rvo.$(CXX).*.exe)
diff --git a/nrvo_by_default/nmake.mk b/nrvo_by_default/nmake.mk
new file mode 100644
index 0000000..45aefd4
--- /dev/null
+++ b/nrvo_by_default/nmake.mk
@@ -0,0 +1,21 @@
+CXXFLAGS = /nologo /W4 /EHsc /MT /DNDEBUG
+
+all: rvo.cl.Od.exe rvo.cl.O1.exe rvo.cl.O2.exe rvo.cl.Ox.exe
+
+rvo.cl.Od.exe: rvo.cpp
+	$(CXX) $(CXXFLAGS) /Od /Fe:$@ $**
+
+rvo.cl.O1.exe: rvo.cpp
+	$(CXX) $(CXXFLAGS) /O1 /Fe:$@ $**
+
+rvo.cl.O2.exe: rvo.cpp
+	$(CXX) $(CXXFLAGS) /O2 /Fe:$@ $**
+
+rvo.cl.Ox.exe: rvo.cpp
+	$(CXX) $(CXXFLAGS) /Ox /Fe:$@ $**
+
+clean:
+	del rvo.obj
+
+clean-all: clean
+	del rvo.cl.*.exe
diff --git a/nrvo_by_default/rvo.cpp b/nrvo_by_default/rvo.cpp
new file mode 100644
index 0000000..f8c8f32
--- /dev/null
+++ b/nrvo_by_default/rvo.cpp
@@ -0,0 +1,73 @@
+#include <iostream>
+#include <utility>
+
+namespace
+{
+    class C
+    {
+    public:
+        explicit C()
+        {
+            std::cout << "\tC::C()\n";
+        }
+
+        C(C&&) noexcept
+        {
+            std::cout << "\tC::C(C&&)\n";
+        }
+
+        C(const C&)
+        {
+            std::cout << "\tC::C(const C&)\n";
+        }
+
+        C& operator=(C&&) noexcept
+        {
+            std::cout << "\tC::operator=(C&&)\n";
+            return *this;
+        }
+
+        C& operator=(const C&)
+        {
+            std::cout << "\tC::operator=(const C&)\n";
+            return *this;
+        }
+
+        ~C()
+        {
+            std::cout << "\tC::~C()\n";
+        }
+    };
+
+    C make_rvo()
+    {
+        return C{};
+    }
+
+    C make_nrvo()
+    {
+        C c;
+        return c;
+    }
+}
+
+int main()
+{
+    {
+        std::cout << "C c\n";
+        C c;
+    }
+    {
+        std::cout << "C c(make_rvo())\n";
+        C c(make_rvo());
+    }
+    {
+        std::cout << "C c{make_rvo()}\n";
+        C c{make_rvo()};
+    }
+    {
+        std::cout << "C c = make_rvo()\n";
+        C c = make_rvo();
+    }
+    return 0;
+}