diff --git a/plugin/CMakeLists.txt b/plugin/CMakeLists.txt
index 673a48b..e17c2fb 100644
--- a/plugin/CMakeLists.txt
+++ b/plugin/CMakeLists.txt
@@ -1,4 +1,4 @@
-add_library(selfpatch-slr SHARED main.cpp attrib.cpp)
+add_library(selfpatch-slr SHARED main.cpp attrib.cpp access_discover.cpp)
 
 set_target_properties(selfpatch-slr PROPERTIES PREFIX "")
 target_compile_definitions(selfpatch-slr PRIVATE _GNU_SOURCE)
diff --git a/plugin/access_discover.cpp b/plugin/access_discover.cpp
new file mode 100644
index 0000000..1ab3d7b
--- /dev/null
+++ b/plugin/access_discover.cpp
@@ -0,0 +1,83 @@
+#include "access_discover.h"
+
+#include <iostream>
+
+static void print_gimple_tree(tree t, int depth, int indent = 2) {
+	if (!t)
+		return;
+
+	for (int i = 0; i < depth; ++i)
+		std::cout << " ";
+
+	std::cout << get_tree_code_name(TREE_CODE(t));
+
+	if (TREE_CODE(t) == FIELD_DECL && DECL_NAME(t))
+		std::cout << " <" << IDENTIFIER_POINTER(DECL_NAME(t)) << ">";
+	else if (TREE_CODE(t) == SSA_NAME && SSA_NAME_VAR(t) && DECL_NAME(SSA_NAME_VAR(t)))
+		std::cout << " <ssa " << IDENTIFIER_POINTER(DECL_NAME(SSA_NAME_VAR(t))) << ">";
+
+	std::cout << std::endl;
+
+	for (int i = 0; i < TREE_CODE_LENGTH(TREE_CODE(t)); ++i)
+		print_gimple_tree(TREE_OPERAND(t, i), depth + indent, indent);
+}
+
+static void print_gimple_statement(gimple* stmt) {
+	if (!stmt)
+		return;
+
+	print_gimple_stmt(stdout, stmt, 0, TDF_NONE);
+
+	for (unsigned i = 0; i < gimple_num_ops(stmt); ++i) {
+		tree operand = gimple_op(stmt, i);
+		print_gimple_tree(operand, 2, 2);
+	}
+}
+
+static int scan_gimple_statement(const char* funcname, gimple_stmt_iterator* gsi) {
+	/*
+	gimple *stmt = gsi_stmt(gsi);
+	scan_stmt_for_offsetof(funcname, &gsi);
+	for (unsigned i = 0; i < gimple_num_ops(stmt); ++i) {
+		tree op = gimple_op(stmt, i);
+		scan_tree_for_components(op, funcname, &gsi);
+	}
+
+	Build map: location->LocationPattern
+	*/
+	print_gimple_statement(gsi_stmt(*gsi));
+	return 0;
+}
+
+static void clean_unnecessary_locations() {
+	// Remove all LocationPatterns that do no do any relevant struct accesses
+}
+
+static const pass_data access_discover_pass_data = {
+	GIMPLE_PASS,
+	"access_discover",
+	OPTGROUP_NONE,
+	TV_NONE,
+	0,0,0,0,
+	TODO_update_ssa | TODO_cleanup_cfg | TODO_verify_il
+};
+
+access_discover_pass::access_discover_pass(gcc::context *ctxt) : gimple_opt_pass(access_discover_pass_data, ctxt) {}
+
+unsigned int access_discover_pass::execute(function* fun) {
+	const char* funcname = fun->decl && DECL_NAME(fun->decl)
+		? IDENTIFIER_POINTER(DECL_NAME(fun->decl))
+		: "<anonymous>";
+
+	basic_block bb;
+	FOR_EACH_BB_FN(bb, fun) {
+		for (gimple_stmt_iterator gsi = gsi_start_bb(bb); !gsi_end_p(gsi); gsi_next(&gsi)) {
+			int stmt_scan_success;
+			if ((stmt_scan_success = scan_gimple_statement(funcname, &gsi)) != 0)
+				return stmt_scan_success;
+		}
+	}
+
+	clean_unnecessary_locations();
+	return 0;
+}
diff --git a/plugin/access_discover.h b/plugin/access_discover.h
new file mode 100644
index 0000000..22a14b9
--- /dev/null
+++ b/plugin/access_discover.h
@@ -0,0 +1,11 @@
+#pragma once
+#include "gcc_includes.h"
+
+struct access_discover_pass : gimple_opt_pass {
+	access_discover_pass(gcc::context *ctxt);
+	unsigned int execute(function* fun) override;
+};
+
+#define ACCESS_DISCOVER_PASS_REFPASS "optimized"
+#define ACCESS_DISCOVER_PASS_POSOP PASS_POS_INSERT_AFTER
+
diff --git a/plugin/attrib.cpp b/plugin/attrib.cpp
index c9dd8b5..e518eaf 100644
--- a/plugin/attrib.cpp
+++ b/plugin/attrib.cpp
@@ -1,7 +1,6 @@
 #include "attrib.h"
 
-#include <gcc-plugin.h>
-#include <tree.h>
+#include "gcc_includes.h"
 
 #include <unordered_set>
 #include <string>
diff --git a/plugin/gcc_includes.h b/plugin/gcc_includes.h
new file mode 100644
index 0000000..dd1b862
--- /dev/null
+++ b/plugin/gcc_includes.h
@@ -0,0 +1,23 @@
+#ifndef GCC_PLUGIN_INCLUDES_H
+#define GCC_PLUGIN_INCLUDES_H
+
+#include <gcc-plugin.h>
+#include <plugin-version.h>
+#include <tree.h>
+#include <gimple.h>
+#include <gimplify.h>
+#include <gimple-iterator.h>
+#include <basic-block.h>
+#include <gimple-ssa.h>
+#include <tree-pass.h>
+#include <pretty-print.h>
+#include <tree-pretty-print.h>
+#include <diagnostic.h>
+#include <gimple-pretty-print.h>
+#include <obstack.h>
+#include <cgraph.h>
+#include <context.h>
+#include <function.h>
+#include <builtins.h>
+
+#endif
diff --git a/plugin/main.cpp b/plugin/main.cpp
index 8d5b72f..36f3dae 100644
--- a/plugin/main.cpp
+++ b/plugin/main.cpp
@@ -1,8 +1,8 @@
 #include <iostream>
-#include <gcc-plugin.h>
-#include <plugin-version.h>
 
+#include "gcc_includes.h"
 #include "attrib.h"
+#include "access_discover.h"
 
 int plugin_is_GPL_compatible;
 
@@ -14,5 +14,12 @@ int plugin_init(plugin_name_args *plugin_info, plugin_gcc_version *version) {
 
 	register_callback(plugin_info->base_name, PLUGIN_ATTRIBUTES, register_attributes, NULL);
 
+	struct register_pass_info access_discover_pass_info;
+	access_discover_pass_info.pass = new access_discover_pass(nullptr);
+	access_discover_pass_info.ref_pass_instance_number = 1;
+	access_discover_pass_info.reference_pass_name = ACCESS_DISCOVER_PASS_REFPASS;
+	access_discover_pass_info.pos_op = ACCESS_DISCOVER_PASS_POSOP;
+	register_callback(plugin_info->base_name, PLUGIN_PASS_MANAGER_SETUP, nullptr, &access_discover_pass_info);
+
 	return 0;
 }
diff --git a/subject/offsetof_passthrough.h b/subject/offsetof_passthrough.h
index a3be078..88ba956 100644
--- a/subject/offsetof_passthrough.h
+++ b/subject/offsetof_passthrough.h
@@ -10,9 +10,12 @@ static size_t __spslr_offsetof(const char *t, const char *m, size_t v) {
 	return v;
 }
 
-/* Replace __builtin_offsetof with encoding of type and member that survives C frontend */
+/*
+Replace __builtin_offsetof with encoding of type and member that survives C frontend
+Macro recursion prevention leaves the inner __builtin_offsetof there, otherwise use "(((size_t)&((T*)0)->M))"
+*/
 #undef __builtin_offsetof
 #define __builtin_offsetof(T,M) \
-	((size_t (*)(const char*, const char*, size_t))__spslr_offsetof)((#T), (#M), (((size_t)&((T*)0)->M)))
+	((size_t (*)(const char*, const char*, size_t))__spslr_offsetof)((#T), (#M), __builtin_offsetof(T,M))
 
 #endif