Feature/memory arena improvements (#633)

* First pass at MemoryArena.

* First pass at RandomGenerator.

* Extract TestContext into external source file.

* Fix warning on printf.

* Use enum classes for Test enums.
OutputMode -> TestOutputMode.

* First pass at FreeList unit test.

* Auto registering tests.
Improvements to RandomGenerator.

* Remove the need for unitTest headers - cos can use registering.

* Added unitTest for MemoryArena.

* Do unit tests.

* Fix typo.

* Fix problem limiting errors from TestContext.

* Refactor of MemoryArena
* Removed the ability to rewind (to improve memory usage/simplify)
* Better memory usage - around oversized blocks
  + Will keep allocating from a normal block if more than 1/3 memory left, or an oversided block is allocated

* Better unitTest coverage for MemoryArena.

* Fixes based on code review

* Remove e prefix from enum class types for TestContext
* Added extra checking for allocations sizes
* Fixed some typos
* Added std::is_pod test to allocateAndCopyArray

* Add include for is_pod needed for linux build.

1 files changed, 30 insertions, 19 deletions

diff --git a/tools/slang-test/unit-test-memory-arena.cpp b/tools/slang-test/unit-test-memory-arena.cpp
index 69eed520a..20a7e047d 100644
--- a/tools/slang-test/unit-test-memory-arena.cpp
+++ b/tools/slang-test/unit-test-memory-arena.cpp
@@ -123,15 +123,23 @@ static void memoryArenaUnitTest()
         blocks.Add(arena.allocate(blockSize * 2));
         blocks.Add(arena.allocate(100));
 
-        while (blocks.Count())
+        arena.deallocateAll();
+        blocks.Add(arena.allocate(100));
+        blocks.Add(arena.allocate(blockSize * 2));
+
+        arena.reset();
+
         {
-            arena.deallocateLast(blocks.Last());
-            blocks.RemoveLast();
+            uint32_t data[] = { 1, 2, 3 };
+
+            const uint32_t* copy = arena.allocateAndCopyArray(data, SLANG_COUNT_OF(data));
+
+            SLANG_CHECK(::memcmp(copy, data, sizeof(data)) == 0);
         }
     }
 
     {
-
+        int count = 0;
         const size_t blockSize = 1024;
 
         for (TestMode mode = TestMode(0); int(mode) < int(TestMode::eCount); mode = TestMode(int(mode) + 1))
@@ -143,32 +151,30 @@ static void memoryArenaUnitTest()
 
             List<Block> blocks;
 
-            for (int i = 0; i < 1000; i++)
+            for (int i = 0; i < 10000; i++)
             {
-                int var = randGen.nextInt32() & 0x3ff;
+                count++;
+
+                const int var = randGen.nextInt32() & 0x3ff;
                 if (var < 3 && blocks.Count() > 0)
                 {
-                    if (var == 0)
-                    {
-                        // Do a single dealloc
-                        arena.deallocateLast(blocks.Last().m_data);
-                        blocks.RemoveLast();
-                    }
-                    else if (var == 1)
+                    if (var == 1)
                     {
                         // Deallocate everything
                         arena.deallocateAll();
                         blocks.Clear();
+                    }   
+                    else if (var == 2)
+                    {
+                        arena.reset();
+                        blocks.Clear();
                     }
                     else
                     {
-                        // Do a multiple dealloc
-                        int index = randGen.nextInt32UpTo(int(blocks.Count()));
+                        size_t usedMemory = arena.calcTotalMemoryUsed();
+                        size_t allocatedMemory = arena.calcTotalMemoryAllocated();
 
-                        // Deallocate all afterwards
-                        arena.deallocateAllFrom(blocks[index].m_data);
-
-                        blocks.SetSize(index);
+                        SLANG_CHECK(allocatedMemory >= usedMemory);
                     }
                 }
                 else
@@ -180,6 +186,11 @@ static void memoryArenaUnitTest()
                     {
                         sizeInBytes += blockSize;
                     }
+                    else if ((randGen.nextInt32() & 0xff) < 2)
+                    {
+                        // Let's try for a block that's awkwardly sized 
+                        sizeInBytes = blockSize / 3 + 10;
+                    }
 
                     const uint8_t value = uint8_t(randGen.nextInt32());