Feature/source loc refactor (#668)

* * Remove the need for IRHighLevelDecoration in Emit
* Use the IRLayoutDecoration for GeometryShaderPrimitiveTypeModifier

* Initial look at at variable byte encoding, and simple unit test.

* Fixing problems with comparison due to naming differences with slang/fxc.

* * More tests and perf improvements for byte encoding.
* Mechanism to detect processor and processor features in main slang header.

* Split out cpu based defines into slang-cpu-defines.h so do not polute slang.h

* Support for variable byte encoding on serialization.

* Removed unused flag.

* Fix warning.

* Fix calcMsByte32 for 0 values without using intrinsic.

* Fix a mistake in calculating maximum instruction size.

* Introduced the idea of SourceUnit.

* Small improvements around naming.
Add more functionality - including getting the HumaneLoc.

* Add support for #line default

* Compiling with new SourceLoc handling.

* Fix off by one on #line directives.

* Can use 32bits for SourceLoc. Fix serialize to use that.

* Small fixes and comment on usage.

* Premake run.

* Fix signed warning.

* Fix typo on StringSlicePool::has found in review.

1 files changed, 43 insertions, 0 deletions

diff --git a/source/core/slang-string-slice-pool.cpp b/source/core/slang-string-slice-pool.cpp
new file mode 100644
index 000000000..88963d68f
--- /dev/null
+++ b/source/core/slang-string-slice-pool.cpp
@@ -0,0 +1,43 @@
+#include "slang-string-slice-pool.h"
+
+namespace Slang {
+
+StringSlicePool::StringSlicePool() :
+    m_arena(1024)
+{
+    clear();
+}
+
+void StringSlicePool::clear()
+{
+    m_slices.SetSize(1);
+    m_slices[0] = UnownedStringSlice::fromLiteral("");
+
+    m_map.Clear();
+}
+
+StringSlicePool::Handle StringSlicePool::add(const Slice& slice)
+{
+    const int* indexPtr = m_map.TryGetValue(slice);
+    if (indexPtr)
+    {
+        return Handle(*indexPtr);
+    }
+
+    // Create a scoped copy
+    UnownedStringSlice scopePath(m_arena.allocateString(slice.begin(), slice.size()), slice.size());
+
+    const int index = int(m_slices.Count());
+
+    m_slices.Add(scopePath);
+    m_map.Add(scopePath, index);
+    return Handle(index);
+}
+
+int StringSlicePool::findIndex(const Slice& slice) const
+{
+    const int* index = m_map.TryGetValue(slice);
+    return index ? *index : -1;
+
+}
+} // namespace Slang