Split compiled module code & data segments and use mprotect to make a module host-executable

libs/jit/include/pslang/jit/abi.hpp

@@ -7,7 +7,7 @@ namespace pslang::jit
 	{
 		itanium,
 		msvc,
-		arm,
+		armv8,
 	};
 
 }

libs/jit/include/pslang/jit/compiled_module.hpp

@@ -10,10 +10,16 @@ namespace pslang::jit
 {
 
 	struct compiled_module
+	{
+		struct segment
 		{
 			blob memory;
 			std::unordered_map<std::string, std::size_t> symbol_table;
-		std::size_t entry_point;
+		};
+
+		segment data;
+		segment code;
+		std::size_t entry_point; // in code segment
 		jit::abi abi;
 	};
 

libs/jit/source/executable.cpp

@@ -6,24 +6,23 @@
 #include <sys/mman.h>
 #endif
 
+#ifdef __APPLE__
+#include <sys/mman.h>
+#endif
+
 namespace pslang::jit
 {
 
 	compiled_module make_host_executable(compiled_module module)
 	{
-#ifdef __linux__
-		if (module.abi != abi::itanium)
+#if defined(__linux__) || defined(__APPLE__)
+		if (module.abi != abi::itanium && module.abi != abi::armv8)
 			throw std::runtime_error("Abi mismatch");
 
-		auto ptr = (std::uint8_t *)mmap(nullptr, module.memory.size, PROT_READ | PROT_EXEC, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
-		auto shared_ptr = std::shared_ptr<std::uint8_t>(ptr, [size = module.memory.size](std::uint8_t * ptr){ munmap(ptr, size); });
+		// Assume the module code memory was obtained via mmap
+		mprotect(module.code.memory.data.get(), module.code.memory.size, PROT_READ | PROT_EXEC);
 
-		return compiled_module {
-			.memory = blob(shared_ptr, module.memory.size),
-			.symbol_table = std::move(module.symbol_table),
-			.entry_point = module.entry_point,
-			.abi = module.abi,
-		};
+		return module;
 #else
 		throw std::runtime_error("Host-executable modules are not supported for this platform");
 #endif

libs/jit/source/jit.cpp

@@ -6,8 +6,8 @@ namespace pslang::jit
 	compiled_module compile(ast::statement_list_ptr const & /* statements */, jit::abi abi)
 	{
 		return {
-			.memory = {},
-			.symbol_table = {},
+			.data = {},
+			.code = {},
 			.entry_point = 0,
 			.abi = abi,
 		};