[libcxxabi] Refactor test timing logic and disable by default.

Summary:
When using LIT the timing output is entirely unused but introduces a dependency on `<chrono>`. When libc++ is built without a montonic clock this causes some of the tests to fail.
This patch factors out all of the timing logic into `support/timer.hpp` and disables it by default. To enable the timing you must define `LIBCXXABI_TIME_TESTS`.



Reviewers: mclow.lists, danalbert, jroelofs

Reviewed By: jroelofs

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D6391

git-svn-id: https://llvm.org/svn/llvm-project/libcxxabi/trunk@222701 91177308-0d34-0410-b5e6-96231b3b80d8

7 files changed, 69 insertions, 43 deletions

diff --git a/test/dynamic_cast14.cpp b/test/dynamic_cast14.cpp
index 2145fb4..c929e38 100644
--- a/test/dynamic_cast14.cpp
+++ b/test/dynamic_cast14.cpp
@@ -8,6 +8,7 @@
 //===----------------------------------------------------------------------===//
 
 #include <cassert>
+#include "support/timer.hpp"
 
 namespace t1
 {
@@ -2172,18 +2173,10 @@ void test()
 
 }  // t3
 
-#include <chrono>
-#include <iostream>
-
 int main()
 {
-    typedef std::chrono::high_resolution_clock Clock;
-    typedef Clock::time_point time_point;
-    typedef std::chrono::duration<double, std::micro> NS;
-    time_point t0 = Clock::now();
+    timer t;
     t1::test();
     t2::test();
     t3::test();
-    time_point t1 = Clock::now();
-    std::cout << NS(t1-t0).count() << " microseconds\n";
 }
diff --git a/test/dynamic_cast3.cpp b/test/dynamic_cast3.cpp
index 2ce77f3..afd4ad8 100644
--- a/test/dynamic_cast3.cpp
+++ b/test/dynamic_cast3.cpp
@@ -8,6 +8,7 @@
 //===----------------------------------------------------------------------===//
 
 #include <cassert>
+#include "support/timer.hpp"
 
 /*
 
@@ -2406,15 +2407,9 @@ void test()
 
 }  // t41
 
-#include <chrono>
-#include <iostream>
-
 int main()
 {
-    typedef std::chrono::high_resolution_clock Clock;
-    typedef Clock::time_point time_point;
-    typedef std::chrono::duration<double, std::micro> NS;
-    time_point t0 = Clock::now();
+    timer t;
     t1::test();
     t2::test();
     t3::test();
@@ -2456,6 +2451,4 @@ int main()
     t39::test();
     t40::test();
     t41::test();
-    time_point t1 = Clock::now();
-    std::cout << NS(t1-t0).count() << " microseconds\n";
 }
diff --git a/test/dynamic_cast5.cpp b/test/dynamic_cast5.cpp
index 8986969..d7064f4 100644
--- a/test/dynamic_cast5.cpp
+++ b/test/dynamic_cast5.cpp
@@ -8,6 +8,7 @@
 //===----------------------------------------------------------------------===//
 
 #include <cassert>
+#include "support/timer.hpp"
 
 namespace t1
 {
@@ -1298,15 +1299,10 @@ void test()
 
 }  // t9
 
-#include <chrono>
-#include <iostream>
 
 int main()
 {
-    typedef std::chrono::high_resolution_clock Clock;
-    typedef Clock::time_point time_point;
-    typedef std::chrono::duration<double, std::micro> NS;
-    time_point t0 = Clock::now();
+    timer t;
     t1::test();
     t2::test();
     t3::test();
@@ -1316,6 +1312,4 @@ int main()
     t7::test();
     t8::test();
     t9::test();
-    time_point t1 = Clock::now();
-    std::cout << NS(t1-t0).count() << " microseconds\n";
 }
diff --git a/test/dynamic_cast_stress.cpp b/test/dynamic_cast_stress.cpp
index c3e5d0a..95276b2 100644
--- a/test/dynamic_cast_stress.cpp
+++ b/test/dynamic_cast_stress.cpp
@@ -9,8 +9,7 @@
 
 #include <cassert>
 #include <tuple>
-#include <chrono>
-#include <iostream>
+#include "support/timer.hpp"
 
 template <std::size_t Indx, std::size_t Depth>
 struct C
@@ -50,17 +49,16 @@ struct A
 
 void test()
 {
-    typedef std::chrono::high_resolution_clock Clock;
-    typedef std::chrono::duration<double, std::micro> US;
     const std::size_t Width = 10;
     const std::size_t Depth = 5;
     A<Width, Depth> a;
     typedef B<Width/2, Depth> Destination;
 //    typedef A<Width, Depth> Destination;
-    auto t0 = Clock::now();
-    Destination* b = dynamic_cast<Destination*>((C<Width/2, 0>*)&a);
-    auto t1 = Clock::now();
-    std::cout << US(t1-t0).count() << " microseconds\n";
+    Destination *b = nullptr;
+    {
+        timer t;
+        b = dynamic_cast<Destination*>((C<Width/2, 0>*)&a);
+    }
     assert(b != 0);
 }
 
diff --git a/test/lit.cfg b/test/lit.cfg
index 490796b..2d7c403 100644
--- a/test/lit.cfg
+++ b/test/lit.cfg
@@ -237,6 +237,10 @@ if link_flags_str is not None:
 
 # Configure extra compiler flags.
 
+# Always disable timed test when using LIT since the output gets lost and since
+# using the timer requires <chrono> as a dependancy.
+compile_flags += ['-DLIBCXXABI_NO_TIMER']
+
 san = lit_config.params.get('llvm_use_sanitizer', None)
 if san is None:
     san = getattr(config, 'llvm_use_sanitizer', None)
diff --git a/test/support/timer.hpp b/test/support/timer.hpp
new file mode 100644
index 0000000..a3d51d7
--- /dev/null
+++ b/test/support/timer.hpp
@@ -0,0 +1,46 @@
+#ifndef TIMER_HPP
+#define TIMER_HPP
+
+// Define LIBCXXABI_NO_TIMER to disable testing with a timer.
+#ifndef LIBCXXABI_NO_TIMER
+
+#include <chrono>
+#include <iostream>
+
+class timer
+{
+    typedef std::chrono::high_resolution_clock Clock;
+    typedef Clock::time_point TimePoint;
+    typedef std::chrono::microseconds MicroSeconds;
+public:
+    timer() : m_start(Clock::now()) {}
+
+    timer(timer const &) = delete;
+    timer & operator=(timer const &) = delete;
+
+    ~timer()
+    {
+        using std::chrono::duration_cast;
+        TimePoint end = Clock::now();
+        MicroSeconds us = duration_cast<MicroSeconds>(end - m_start);
+        std::cout << us.count() << " microseconds\n";
+    }
+
+private:
+    TimePoint m_start;
+};
+
+#else /* LIBCXXABI_NO_TIMER */
+
+class timer
+{
+public:
+    timer() {}
+    timer(timer const &) = delete;
+    timer & operator=(timer const &) = delete;
+    ~timer() {}
+};
+
+#endif /* LIBCXXABI_TIME_TESTS */
+
+#endif /* TIMER_HPP */
\ No newline at end of file
diff --git a/test/test_demangle.cpp b/test/test_demangle.cpp
index 15cb3a1..8a4685a 100644
--- a/test/test_demangle.cpp
+++ b/test/test_demangle.cpp
@@ -7,12 +7,12 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "support/timer.hpp"
 #include <iostream>
 #include <string>
 #include <cstdlib>
 #include <cxxabi.h>
 #include <cassert>
-#include <chrono>
 
 // Is long double fp80?  (Only x87 extended double has 64-bit mantissa)
 #define LDBL_FP80 (__LDBL_MANT_DIG__ == 64)
@@ -29664,14 +29664,12 @@ void test2()
 
 int main()
 {
-    typedef std::chrono::high_resolution_clock Clock;
-    typedef std::chrono::duration<double> sec;
-    Clock::time_point t0 = Clock::now();
-    test();
-    test2();
-    Clock::time_point t1 = Clock::now();
-    std::cout << sec(t1-t0).count() << " seconds for test\n";
-    std::cout << N / sec(t1-t0).count() / 1000000. << " million symbols per second\n";
+    std::cout << "Testing " << N << " symbols." << std::endl;
+    {
+        timer t;
+        test();
+        test2();
+    }
 #if 0
     std::string input;
     while (std::cin)