Constant time dynamic cast (#1250)

* Constant time dynamic cast.

* Use getClassInfo virtual function.
Fix problem because of instanciation of specializations was in wrong order for clang.

* Improve comments.

* Improve comment.

* Ensure s_first is defined before kClassInfo, to ensure construction ordering.

1 files changed, 13 insertions, 12 deletions

diff --git a/source/slang/slang.cpp b/source/slang/slang.cpp
index 08c996fd2..6c1a59ea4 100644
--- a/source/slang/slang.cpp
+++ b/source/slang/slang.cpp
@@ -116,20 +116,21 @@ void Session::init()
     // Set all the shared library function pointers to nullptr
     ::memset(m_sharedLibraryFunctions, 0, sizeof(m_sharedLibraryFunctions));
 
+    {
+        static auto res = SyntaxClassBase::ClassInfo::initRanges();
+    }
+
     // Initialize the lookup table of syntax classes:
 
-    #define SYNTAX_CLASS(NAME, BASE) \
-        mapNameToSyntaxClass.Add(getNamePool()->getName(#NAME), getClass<NAME>());
-
-#include "slang-object-meta-begin.h"
-#include "slang-syntax-base-defs.h"
-#include "slang-expr-defs.h"
-#include "slang-decl-defs.h"
-#include "slang-modifier-defs.h"
-#include "slang-stmt-defs.h"
-#include "slang-type-defs.h"
-#include "slang-val-defs.h"
-#include "slang-object-meta-end.h"
+    // We can just iterate over the class pointers.
+    // NOTE! That this adds the names of the abstract classes too(!)
+    {
+        const SyntaxClassBase::ClassInfo* info = SyntaxClassBase::ClassInfo::s_first;
+        for (; info; info = info->m_next)
+        {
+            mapNameToSyntaxClass.Add(getNamePool()->getName(info->m_name), SyntaxClass<Slang::RefObject>(info));
+        }
+    }
 
     // Make sure our source manager is initialized
     builtinSourceManager.initialize(nullptr, nullptr);