Add 'xo-expression/' from commit '5ac3c03a0c'

git-subtree-dir: xo-expression
git-subtree-mainline: d0f5ccc1ce
git-subtree-split: 5ac3c03a0c

xo-expression/include/xo/expression/PrimitiveInterface.hpp

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+/** @file PrimitiveInterface.hpp
+ *
+ *  Author: Roland Conybeare
+ **/
+
+#pragma once
+
+#include "FunctionInterface.hpp"
+#include "llvmintrinsic.hpp"
+
+//#include <cstdint>
+
+#include <type_traits>
+namespace xo {
+    namespace ast {
+        class PrimitiveInterface : public FunctionInterface {
+        public:
+            using void_function_type = void (*)();
+
+        public:
+            PrimitiveInterface(TypeDescr fn_type)
+                : FunctionInterface(exprtype::primitive, fn_type) {}
+
+            /** downcast from Expression **/
+            static ref::brw<PrimitiveInterface> from(ref::brw<Expression> x) {
+                return ref::brw<PrimitiveInterface>::from(x);
+            }
+
+            /** if true,  Jit will try to explicitly symbol for this primitive
+             *  (instead of looking it up in host process).
+             *  Don't know if this works.
+             *  Do know it's not needed for ::sin(), ::sqrt().
+             *  Do know that my extern "C" functions like ::mul_i32(), ::mul_f64()
+             *  need something else.
+             **/
+            virtual bool explicit_symbol_def() const = 0;
+
+            /** function address for this primitive **/
+            virtual void_function_type function_address() const = 0;
+
+            /** get llvm intrinsic hint for this primitive **/
+            virtual llvmintrinsic intrinsic() const = 0;
+
+            // virtual const std::string & name() const;
+            // virtual int n_arg() const;
+            // virtual TypeDescr fn_retval() const;
+            // virtual TypeDescr fn_arg(uint32_t i) const;
+
+            // ----- Expression -----
+
+            virtual std::set<std::string> get_free_variables() const override {
+                return std::set<std::string>();
+            }
+
+            virtual std::size_t visit_preorder(VisitFn visitor_fn) override {
+                visitor_fn(this);
+                return 1;
+            }
+
+            virtual std::size_t visit_layer(VisitFn visitor_fn) override {
+                visitor_fn(this);
+                return 1;
+            }
+
+            virtual rp<Expression> xform_layer(TransformFn xform_fn) override {
+                return xform_fn(this);
+            }
+
+            virtual void attach_envs(ref::brw<Environment> /*p*/) override {}
+
+        private:
+        }; /*PrimitiveInterface*/
+    } /*namespace ast*/
+} /*namespace xo*/
+
+
+/** end PrimitiveInterface.hpp **/