diff --git a/pinpoint/CMakeLists.txt b/pinpoint/CMakeLists.txt
index 3ff5228..b6711c4 100644
--- a/pinpoint/CMakeLists.txt
+++ b/pinpoint/CMakeLists.txt
@@ -9,3 +9,4 @@ message(STATUS "GCC plugin path: ${GCC_PLUGIN_PATH}")
 target_include_directories(spslr_pinpoint PRIVATE ${GCC_PLUGIN_PATH}/include ${CMAKE_CURRENT_SOURCE_DIR}/safegcc ${CMAKE_CURRENT_SOURCE_DIR})
 
 add_subdirectory(stage0)
+add_subdirectory(stage1)
diff --git a/pinpoint/pinpoint.cpp b/pinpoint/pinpoint.cpp
index 863ade2..e812438 100644
--- a/pinpoint/pinpoint.cpp
+++ b/pinpoint/pinpoint.cpp
@@ -4,6 +4,7 @@
 #include <safe-plugin-version.h>
 
 #include <stage0.h>
+#include <stage1.h>
 
 int plugin_is_GPL_compatible;
 
@@ -26,7 +27,14 @@ int plugin_init(struct plugin_name_args* plugin_info, struct plugin_gcc_version*
 	separate_offset_pass_info.pos_op = PASS_POS_INSERT_AFTER;
 	register_callback(plugin_info->base_name, PLUGIN_PASS_MANAGER_SETUP, nullptr, &separate_offset_pass_info);
 
-	// Stage 1 -> TODO
+	// Stage 1 -> stage 0 separators are replaced with inline assembly
+
+	struct register_pass_info asm_offset_pass_info;
+	asm_offset_pass_info.pass = new asm_offset_pass(nullptr);
+	asm_offset_pass_info.ref_pass_instance_number = 1;
+	asm_offset_pass_info.reference_pass_name = "separate_offset";
+	asm_offset_pass_info.pos_op = PASS_POS_INSERT_AFTER;
+	register_callback(plugin_info->base_name, PLUGIN_PASS_MANAGER_SETUP, nullptr, &asm_offset_pass_info);
 
 	return 0;
 }
diff --git a/pinpoint/safegcc/safe-gimple.h b/pinpoint/safegcc/safe-gimple.h
index ad6e0a9..9181c77 100644
--- a/pinpoint/safegcc/safe-gimple.h
+++ b/pinpoint/safegcc/safe-gimple.h
@@ -1,4 +1,5 @@
 #include <safe-gcc-plugin.h>
+#include <safe-tree.h>
 
 #ifndef SAFEGCC_GIMPLE_H
 #define SAFEGCC_GIMPLE_H
diff --git a/pinpoint/stage0/separator.cpp b/pinpoint/stage0/separator.cpp
index 39b22bb..b940411 100644
--- a/pinpoint/stage0/separator.cpp
+++ b/pinpoint/stage0/separator.cpp
@@ -1,5 +1,6 @@
 #include <stage0.h>
 #include <pinpoint_config.h>
+#include <pinpoint_error.h>
 
 static tree separator_decl = NULL_TREE;
 
@@ -62,8 +63,40 @@ gimple* make_stage0_gimple_separator(tree lhs, UID target, std::size_t offset) {
 	return call;
 }
 
-bool is_stage0_separator(gimple* stmt, UID& target, std::size_t& offset) {
-	// TODO
-	return false;
+static bool decl_is_separator(tree fndecl) {
+	if (!fndecl)
+		return false;
+
+	tree name_tree = DECL_NAME(fndecl);
+	if (!name_tree)
+		return false;
+
+	const char* name = IDENTIFIER_POINTER(name_tree);
+	if (!name)
+		return false;
+
+	return strcmp(name, SPSLR_PINPOINT_STAGE0_SEPARATOR) == 0;
+}
+
+bool is_stage0_separator(gimple* stmt, UID& target, std::size_t& offset) {
+	if (!stmt || !is_gimple_call(stmt))
+		return false;
+
+	tree fndecl = gimple_call_fndecl(stmt);
+	if (!decl_is_separator(fndecl))
+		return false;
+
+	tree arg0 = gimple_call_arg (stmt, 0);
+	tree arg1 = gimple_call_arg (stmt, 1);
+
+	if (!arg0 || TREE_CODE(arg0) != INTEGER_CST)
+		pinpoint_fatal("is_state0_separator failed to get target UID from separator");
+
+	if (!arg1 || TREE_CODE(arg1) != INTEGER_CST)
+		pinpoint_fatal("is_state0_separator failed to get field offset from separator");
+
+	target = static_cast<UID>(tree_to_uhwi(arg0));
+	offset = static_cast<std::size_t>(tree_to_uhwi(arg1));
+	return true;
 }
 
diff --git a/pinpoint/stage1/CMakeLists.txt b/pinpoint/stage1/CMakeLists.txt
new file mode 100644
index 0000000..88aeb12
--- /dev/null
+++ b/pinpoint/stage1/CMakeLists.txt
@@ -0,0 +1,2 @@
+target_sources(spslr_pinpoint PRIVATE asm_offset_pass.cpp)
+target_include_directories(spslr_pinpoint PRIVATE .)
diff --git a/pinpoint/stage1/asm_offset_pass.cpp b/pinpoint/stage1/asm_offset_pass.cpp
new file mode 100644
index 0000000..399fb23
--- /dev/null
+++ b/pinpoint/stage1/asm_offset_pass.cpp
@@ -0,0 +1,31 @@
+#include <stage1.h>
+#include <stage0.h>
+
+static void separator_assemble_maybe(gimple_stmt_iterator* gsi) {
+	// TODO
+}
+
+static const pass_data asm_offset_pass_data = {
+	GIMPLE_PASS,
+	"asm_offset",
+	OPTGROUP_NONE,
+	TV_NONE,
+	0,0,0,0,
+	TODO_update_ssa
+};
+
+asm_offset_pass::asm_offset_pass(gcc::context* ctxt) : gimple_opt_pass(asm_offset_pass_data, ctxt) {}
+
+unsigned int asm_offset_pass::execute(function* fn) {
+	if (!fn)
+		return 0;
+
+	basic_block bb;
+	FOR_EACH_BB_FN(bb, fn) {
+		for (gimple_stmt_iterator gsi = gsi_start_bb(bb); !gsi_end_p(gsi); gsi_next(&gsi))
+			separator_assemble_maybe(&gsi);
+	}
+
+	return 0;
+}
+
diff --git a/pinpoint/stage1/stage1.h b/pinpoint/stage1/stage1.h
new file mode 100644
index 0000000..b6d9236
--- /dev/null
+++ b/pinpoint/stage1/stage1.h
@@ -0,0 +1,8 @@
+#pragma once
+
+#include <safe-gimple.h>
+
+struct asm_offset_pass : gimple_opt_pass {
+	asm_offset_pass(gcc::context* ctxt);
+	unsigned int execute(function* fn) override;
+};