diff --git a/src/config/config.cc b/src/config/config.cc
index 6fb1dfcc..f4d99ca1 100644
--- a/src/config/config.cc
+++ b/src/config/config.cc
@@ -151,21 +151,35 @@ template <> struct convert<scope_t> {
     }
 };
 
-template <> struct convert<std::vector<source_location::variant>> {
-    static bool decode(
-        const Node &node, std::vector<source_location::variant> &rhs)
+template <> struct convert<std::vector<source_location>> {
+    static bool decode(const Node &node, std::vector<source_location> &rhs)
     {
         for (auto it = node.begin(); it != node.end(); ++it) {
             const YAML::Node &n = *it;
             if (n["usr"]) {
-                rhs.emplace_back(n["usr"].as<source_location::usr>());
+                source_location loc;
+                loc.location_type = source_location::location_t::usr;
+                loc.location = n["usr"].as<std::string>();
+                rhs.emplace_back(std::move(loc));
             }
             else if (n["marker"]) {
-                rhs.emplace_back(n["marker"].as<source_location::marker>());
+                source_location loc;
+                loc.location_type = source_location::location_t::marker;
+                loc.location = n["marker"].as<std::string>();
+                rhs.emplace_back(std::move(loc));
             }
             else if (n["file"] && n["line"]) {
-                rhs.emplace_back(std::make_pair(
-                    n["file"].as<std::string>(), n["line"].as<int>()));
+                source_location loc;
+                loc.location_type = source_location::location_t::fileline;
+                loc.location = n["file"].as<std::string>() + ":" +
+                    n["line"].as<std::string>();
+                rhs.emplace_back(std::move(loc));
+            }
+            else if (n["function"]) {
+                source_location loc;
+                loc.location_type = source_location::location_t::function;
+                loc.location = n["function"].as<std::string>();
+                rhs.emplace_back(std::move(loc));
             }
             else {
                 return false;
@@ -261,7 +275,7 @@ template <> struct convert<sequence_diagram> {
             return false;
 
         if (node["start_from"])
-            rhs.start_from = node["start_from"].as<decltype(rhs.start_from)>();
+            rhs.start_from = node["start_from"].as<std::vector<source_location>>();
 
         return true;
     }
diff --git a/src/config/config.h b/src/config/config.h
index d085e40e..8516ce1a 100644
--- a/src/config/config.h
+++ b/src/config/config.h
@@ -81,13 +81,9 @@ struct diagram {
 };
 
 struct source_location {
-    using usr = std::string;
-    using marker = std::string;
-    using file = std::pair<std::string, int>;
-    // std::variant requires unique types, so we cannot add
-    // marker here, we need sth like boost::mp_unique
-    // type function
-    using variant = std::variant<usr, /* marker, */ file>;
+    enum class location_t { usr, marker, fileline, function };
+    location_t location_type;
+    std::string location;
 };
 
 struct class_diagram : public diagram {
@@ -102,7 +98,7 @@ struct class_diagram : public diagram {
 struct sequence_diagram : public diagram {
     virtual ~sequence_diagram() = default;
 
-    std::vector<source_location::variant> start_from;
+    std::vector<source_location> start_from;
 };
 
 struct config {
diff --git a/src/main.cc b/src/main.cc
index 1efbadbb..8b1d4f2c 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -77,10 +77,7 @@ int main(int argc, const char *argv[])
     LOG_INFO("Loading compilation database from {} directory",
         config.compilation_database_dir);
 
-    auto db =
-        compilation_database::from_directory(config.compilation_database_dir);
-
-    cppast::libclang_compilation_database db2(config.compilation_database_dir);
+    cppast::libclang_compilation_database db(config.compilation_database_dir);
 
     for (const auto &[name, diagram] : config.diagrams) {
         // If there are any specific diagram names provided on the command line,
@@ -100,7 +97,7 @@ int main(int argc, const char *argv[])
         if (std::dynamic_pointer_cast<class_diagram>(diagram)) {
             auto model =
                 clanguml::class_diagram::generators::plantuml::generate(
-                    db2, name, dynamic_cast<class_diagram &>(*diagram));
+                    db, name, dynamic_cast<class_diagram &>(*diagram));
 
             ofs << clanguml::class_diagram::generators::plantuml::generator(
                 dynamic_cast<clanguml::config::class_diagram &>(*diagram),
diff --git a/src/sequence_diagram/generators/plantuml/sequence_diagram_generator.cc b/src/sequence_diagram/generators/plantuml/sequence_diagram_generator.cc
index 2c142ef9..43d831d0 100644
--- a/src/sequence_diagram/generators/plantuml/sequence_diagram_generator.cc
+++ b/src/sequence_diagram/generators/plantuml/sequence_diagram_generator.cc
@@ -20,6 +20,9 @@
 
 #include "sequence_diagram/visitor/translation_unit_context.h"
 
+#include <cppast/libclang_parser.hpp>
+#include <cppast/parser.hpp>
+
 namespace clanguml::sequence_diagram::generators::plantuml {
 
 using diagram_model = clanguml::sequence_diagram::model::diagram;
@@ -97,15 +100,20 @@ void generator::generate(std::ostream &ostr) const
         ostr << b << std::endl;
 
     for (const auto &sf : m_config.start_from) {
-        std::string start_from;
-        if (std::holds_alternative<source_location::usr>(sf)) {
-            start_from = std::get<source_location::usr>(sf);
+        if (sf.location_type == source_location::location_t::function) {
+            std::uint_least64_t start_from;
+            for (const auto &[k, v] : m_model.sequences) {
+                if (v.from == sf.location) {
+                    start_from = k;
+                    break;
+                }
+            }
+            generate_activity(m_model.sequences[start_from], ostr);
         }
         else {
             // TODO: Add support for other sequence start location types
             continue;
         }
-        generate_activity(m_model.sequences[start_from], ostr);
     }
     for (const auto &a : m_config.puml.after)
         ostr << a << std::endl;
@@ -120,51 +128,33 @@ std::ostream &operator<<(std::ostream &os, const generator &g)
 }
 
 clanguml::sequence_diagram::model::diagram generate(
-    clanguml::cx::compilation_database &db, const std::string &name,
+    cppast::libclang_compilation_database &db, const std::string &name,
     clanguml::config::sequence_diagram &diagram)
 {
     spdlog::info("Generating diagram {}.puml", name);
     clanguml::sequence_diagram::model::diagram d;
     d.name = name;
 
+    cppast::cpp_entity_index idx;
+    cppast::simple_file_parser<cppast::libclang_parser> parser{
+        type_safe::ref(idx)};
+
+    clanguml::sequence_diagram::visitor::translation_unit_visitor visitor(
+        idx, d, diagram);
+
     // Get all translation units matching the glob from diagram
     // configuration
-    std::vector<std::filesystem::path> translation_units{};
+    std::vector<std::string> translation_units{};
     for (const auto &g : diagram.glob) {
         spdlog::debug("Processing glob: {}", g);
         const auto matches = glob::rglob(g);
         std::copy(matches.begin(), matches.end(),
             std::back_inserter(translation_units));
     }
+    cppast::parse_files(parser, translation_units, db);
 
-    // Process all matching translation units
-    for (const auto &tu_path : translation_units) {
-        spdlog::debug("Processing translation unit: {}",
-            std::filesystem::canonical(tu_path).c_str());
-
-        auto tu = db.parse_translation_unit(tu_path);
-
-        auto cursor = clang_getTranslationUnitCursor(tu);
-
-        if (clang_Cursor_isNull(cursor)) {
-            spdlog::debug("Cursor is NULL");
-        }
-
-        spdlog::debug("Cursor kind: {}",
-            clang_getCString(clang_getCursorKindSpelling(cursor.kind)));
-        spdlog::debug("Cursor name: {}",
-            clang_getCString(clang_getCursorDisplayName(cursor)));
-
-        clanguml::sequence_diagram::visitor::translation_unit_context ctx(
-            d, diagram);
-        auto res = clang_visitChildren(cursor,
-            clanguml::sequence_diagram::visitor::translation_unit_visitor,
-            &ctx);
-
-        spdlog::debug("Processing result: {}", res);
-
-        clang_suspendTranslationUnit(tu);
-    }
+    for (auto &file : parser.files())
+        visitor(file);
 
     return d;
 }
diff --git a/src/sequence_diagram/generators/plantuml/sequence_diagram_generator.h b/src/sequence_diagram/generators/plantuml/sequence_diagram_generator.h
index 5b63cc08..e90557db 100644
--- a/src/sequence_diagram/generators/plantuml/sequence_diagram_generator.h
+++ b/src/sequence_diagram/generators/plantuml/sequence_diagram_generator.h
@@ -24,6 +24,7 @@
 #include "util/util.h"
 
 #include <glob/glob.hpp>
+#include <cppast/libclang_parser.hpp>
 
 #include <filesystem>
 #include <fstream>
@@ -62,7 +63,7 @@ private:
 };
 
 clanguml::sequence_diagram::model::diagram generate(
-    clanguml::cx::compilation_database &db, const std::string &name,
+    cppast::libclang_compilation_database &db, const std::string &name,
     clanguml::config::sequence_diagram &diagram);
 
 }
diff --git a/src/sequence_diagram/model/activity.h b/src/sequence_diagram/model/activity.h
index 4ac2473e..cf054965 100644
--- a/src/sequence_diagram/model/activity.h
+++ b/src/sequence_diagram/model/activity.h
@@ -25,7 +25,7 @@
 namespace clanguml::sequence_diagram::model {
 
 struct activity {
-    std::string usr;
+    std::uint_least64_t usr;
     std::string from;
     std::vector<message> messages;
 };
diff --git a/src/sequence_diagram/model/diagram.h b/src/sequence_diagram/model/diagram.h
index 44984631..6b23c644 100644
--- a/src/sequence_diagram/model/diagram.h
+++ b/src/sequence_diagram/model/diagram.h
@@ -28,7 +28,7 @@ struct diagram {
     bool started{false};
     std::string name;
 
-    std::map<std::string, activity> sequences;
+    std::map<std::uint_least64_t, activity> sequences;
 };
 
 }
diff --git a/src/sequence_diagram/model/message.h b/src/sequence_diagram/model/message.h
index 54a148eb..872d5411 100644
--- a/src/sequence_diagram/model/message.h
+++ b/src/sequence_diagram/model/message.h
@@ -27,9 +27,9 @@ namespace clanguml::sequence_diagram::model {
 struct message {
     message_t type;
     std::string from;
-    std::string from_usr;
+    std::uint_least64_t from_usr;
     std::string to;
-    std::string to_usr;
+    std::uint_least64_t to_usr;
     std::string message;
     std::string return_type;
     unsigned int line;
diff --git a/src/sequence_diagram/visitor/translation_unit_context.cc b/src/sequence_diagram/visitor/translation_unit_context.cc
index 547875b9..ffe490da 100644
--- a/src/sequence_diagram/visitor/translation_unit_context.cc
+++ b/src/sequence_diagram/visitor/translation_unit_context.cc
@@ -25,9 +25,11 @@
 namespace clanguml::sequence_diagram::visitor {
 
 translation_unit_context::translation_unit_context(
+    cppast::cpp_entity_index &idx,
     clanguml::sequence_diagram::model::diagram &diagram,
     const clanguml::config::sequence_diagram &config)
-    : diagram_{diagram}
+    : entity_index_{idx}
+    , diagram_{diagram}
     , config_{config}
 {
 }
@@ -55,6 +57,11 @@ clanguml::sequence_diagram::model::diagram &translation_unit_context::diagram()
     return diagram_;
 }
 
+const cppast::cpp_entity_index &translation_unit_context::entity_index() const
+{
+    return entity_index_;
+}
+
 void translation_unit_context::set_current_method(cx::cursor method)
 {
     current_method_ = method;
diff --git a/src/sequence_diagram/visitor/translation_unit_context.h b/src/sequence_diagram/visitor/translation_unit_context.h
index f80da7e5..e4c48a4d 100644
--- a/src/sequence_diagram/visitor/translation_unit_context.h
+++ b/src/sequence_diagram/visitor/translation_unit_context.h
@@ -21,6 +21,8 @@
 #include "cx/cursor.h"
 #include "sequence_diagram/model/diagram.h"
 
+#include <cppast/cpp_entity_index.hpp>
+
 #include <functional>
 #include <memory>
 #include <string>
@@ -29,7 +31,7 @@ namespace clanguml::sequence_diagram::visitor {
 
 class translation_unit_context {
 public:
-    translation_unit_context(
+    translation_unit_context(cppast::cpp_entity_index &idx,
         clanguml::sequence_diagram::model::diagram &diagram,
         const clanguml::config::sequence_diagram &config);
 
@@ -50,10 +52,13 @@ public:
     cx::cursor &current_method();
 
 private:
-    std::vector<std::string> namespace_;
-    cx::cursor current_method_;
+    // Reference to the cppast entity index
+    cppast::cpp_entity_index &entity_index_;
     clanguml::sequence_diagram::model::diagram &diagram_;
     const clanguml::config::sequence_diagram &config_;
+
+    std::vector<std::string> namespace_;
+    cx::cursor current_method_;
 };
 
 }
diff --git a/src/sequence_diagram/visitor/translation_unit_visitor.cc b/src/sequence_diagram/visitor/translation_unit_visitor.cc
index e3e23c92..1409844f 100644
--- a/src/sequence_diagram/visitor/translation_unit_visitor.cc
+++ b/src/sequence_diagram/visitor/translation_unit_visitor.cc
@@ -20,124 +20,125 @@
 
 #include "translation_unit_context.h"
 
+#include <cppast/cpp_function.hpp>
+#include <cppast/cpp_member_function.hpp>
+#include <cppast/visitor.hpp>
+
 namespace clanguml::sequence_diagram::visitor {
 
-enum CXChildVisitResult translation_unit_visitor(
-    CXCursor cx_cursor, CXCursor cx_parent, CXClientData client_data)
+translation_unit_visitor::translation_unit_visitor(
+    cppast::cpp_entity_index &idx,
+    clanguml::sequence_diagram::model::diagram &diagram,
+    const clanguml::config::sequence_diagram &config)
+    : ctx{idx, diagram, config}
+{
+}
+
+void translation_unit_visitor::process_activities(const cppast::cpp_function &e)
 {
     using clanguml::sequence_diagram::model::activity;
     using clanguml::sequence_diagram::model::diagram;
     using clanguml::sequence_diagram::model::message;
     using clanguml::sequence_diagram::model::message_t;
+    using cppast::cpp_entity;
+    using cppast::cpp_entity_kind;
+    using cppast::cpp_function;
+    using cppast::cpp_member_function;
+    using cppast::cpp_member_function_call;
+    using cppast::visitor_info;
 
-    auto *ctx = (struct translation_unit_context *)client_data;
+    for (const auto &function_call_ptr : e.function_calls()) {
+        const auto &function_call =
+            static_cast<const cpp_member_function_call &>(*function_call_ptr);
 
-    enum CXChildVisitResult ret = CXChildVisit_Break;
+        message m;
+        m.type = message_t::kCall;
 
-    cx::cursor cursor{std::move(cx_cursor)};
-    cx::cursor parent{std::move(cx_parent)};
+        if (!ctx.entity_index()
+                 .lookup_definition(function_call.get_caller_id())
+                 .has_value())
+            continue;
 
-    if (cursor.spelling().empty()) {
-        return CXChildVisit_Recurse;
-    }
+        if (!ctx.entity_index()
+                 .lookup_definition(function_call.get_caller_method_id())
+                 .has_value())
+            continue;
 
-    switch (cursor.kind()) {
-    case CXCursor_FunctionTemplate:
-    case CXCursor_CXXMethod:
-    case CXCursor_FunctionDecl:
-        ctx->set_current_method(cursor);
-        ret = CXChildVisit_Recurse;
-        break;
-    case CXCursor_CallExpr: {
-        auto referenced = cursor.referenced();
-        auto referenced_type = referenced.type();
-        auto referenced_cursor_name = referenced.display_name();
+        if (!ctx.entity_index()
+                 .lookup_definition(function_call.get_callee_id())
+                 .has_value())
+            continue;
 
-        auto semantic_parent = referenced.semantic_parent();
-        auto sp_name = semantic_parent.fully_qualified();
-        auto lexical_parent = cursor.lexical_parent();
-        auto lp_name = lexical_parent.spelling();
+        if (!ctx.entity_index()
+                 .lookup_definition(function_call.get_callee_method_id())
+                 .has_value())
+            continue;
 
-        CXFile f;
-        unsigned int line{};
-        unsigned int column{};
-        unsigned int offset{};
-        clang_getFileLocation(cursor.location(), &f, &line, &column, &offset);
-        std::string file{clang_getCString(clang_getFileName(f))};
+        const auto &caller =
+            ctx.entity_index()
+                .lookup_definition(function_call.get_caller_id())
+                .value();
+        m.from = cx::util::ns(caller) + "::" + caller.name();
 
-        auto &d = ctx->diagram();
-        auto &config = ctx->config();
-        if (referenced.kind() == CXCursor_CXXMethod) {
-            if (config.should_include(sp_name)) {
-                // Get calling object
-                std::string caller{};
-                if (ctx->current_method()
-                        .semantic_parent()
-                        .is_translation_unit() ||
-                    ctx->current_method().semantic_parent().is_namespace()) {
-                    caller = ctx->current_method()
-                                 .semantic_parent()
-                                 .fully_qualified() +
-                        "::" + ctx->current_method().spelling() + "()";
-                }
-                else {
-                    caller = ctx->current_method()
-                                 .semantic_parent()
-                                 .fully_qualified();
-                }
+        if (!ctx.config().should_include(m.from))
+            continue;
 
-                auto caller_usr = ctx->current_method().usr();
-                // Get called object
-                auto callee = referenced.semantic_parent().fully_qualified();
-                auto callee_usr = referenced.semantic_parent().usr();
+        if (caller.kind() == cpp_entity_kind::function_t)
+            m.from += "()";
 
-                // Get called method
-                auto called_message = cursor.spelling();
 
-                // Found method call: CXCursorKind () const
-                spdlog::debug("Adding method call at line {}:{} to diagram {}"
-                              "\n\tCURRENT_METHOD: {}\n\tFROM: '{}'\n\tTO: "
-                              "{}\n\tMESSAGE: {}\n\tFROM_USR: {}\n\tTO_USR: "
-                              "{}\n\tRETURN_TYPE: {}",
-                    file, line, d.name, ctx->current_method().spelling(),
-                    caller, callee, called_message, caller_usr, callee_usr,
-                    referenced.type().result_type().spelling());
+        m.from_usr = type_safe::get(function_call.get_caller_method_id());
 
-                message m;
-                m.type = message_t::kCall;
-                m.from = caller;
-                m.from_usr = caller_usr;
-                m.line = line;
-                m.to = callee;
-                m.to_usr = referenced.usr();
-                m.message = called_message;
-                m.return_type = referenced.type().result_type().spelling();
+        const auto &callee =
+            ctx.entity_index()
+                .lookup_definition(function_call.get_callee_id())
+                .value();
+        m.to = cx::util::ns(callee) + "::" + callee.name();
 
-                if (d.sequences.find(caller_usr) == d.sequences.end()) {
-                    activity a;
-                    a.usr = caller_usr;
-                    a.from = caller;
-                    d.sequences.insert({caller_usr, std::move(a)});
-                }
+        if (!ctx.config().should_include(m.to))
+            continue;
 
-                d.sequences[caller_usr].messages.emplace_back(std::move(m));
-            }
-        }
-        else if (referenced.kind() == CXCursor_FunctionDecl) {
-            // TODO
+        m.to_usr = type_safe::get(function_call.get_callee_method_id());
+
+        const auto &callee_method =
+            ctx.entity_index()
+                .lookup_definition(function_call.get_callee_method_id())
+                .value();
+
+        m.message = callee_method.name();
+
+        if (ctx.diagram().sequences.find(m.from_usr) ==
+            ctx.diagram().sequences.end()) {
+            activity a;
+            a.usr = m.from_usr;
+            a.from = m.from;
+            ctx.diagram().sequences.insert({m.from_usr, std::move(a)});
         }
 
-        ret = CXChildVisit_Recurse;
-        break;
-    }
-    case CXCursor_Namespace: {
-        ret = CXChildVisit_Recurse;
-        break;
-    }
-    default:
-        ret = CXChildVisit_Recurse;
-    }
+        LOG_DBG("Adding sequence {} -{}()-> {}", m.from, m.message, m.to);
 
-    return ret;
+        ctx.diagram().sequences[m.from_usr].messages.emplace_back(std::move(m));
+    }
+}
+
+void translation_unit_visitor::operator()(const cppast::cpp_entity &file)
+{
+    using cppast::cpp_entity;
+    using cppast::cpp_entity_kind;
+    using cppast::cpp_function;
+    using cppast::cpp_member_function;
+    using cppast::cpp_member_function_call;
+    using cppast::visitor_info;
+
+    cppast::visit(file, [&, this](const cpp_entity &e, visitor_info info) {
+        if (e.kind() == cpp_entity_kind::function_t) {
+            const auto &function = static_cast<const cpp_function &>(e);
+            process_activities(function);
+        }
+        else if (e.kind() == cpp_entity_kind::member_function_t) {
+            const auto &member_function = static_cast<const cpp_function &>(e);
+            process_activities(member_function);
+        }
+    });
 }
 }
diff --git a/src/sequence_diagram/visitor/translation_unit_visitor.h b/src/sequence_diagram/visitor/translation_unit_visitor.h
index 752b2ab5..2ff32d63 100644
--- a/src/sequence_diagram/visitor/translation_unit_visitor.h
+++ b/src/sequence_diagram/visitor/translation_unit_visitor.h
@@ -20,10 +20,24 @@
 #include "config/config.h"
 #include "cx/cursor.h"
 #include "sequence_diagram/model/diagram.h"
+#include "sequence_diagram/visitor/translation_unit_context.h"
+
+#include <cppast/cpp_function.hpp>
 
 namespace clanguml::sequence_diagram::visitor {
 
-enum CXChildVisitResult translation_unit_visitor(
-    CXCursor cx_cursor, CXCursor cx_parent, CXClientData client_data);
+class translation_unit_visitor {
+public:
+    translation_unit_visitor(cppast::cpp_entity_index &idx,
+        clanguml::sequence_diagram::model::diagram &diagram,
+        const clanguml::config::sequence_diagram &config);
 
+    void operator()(const cppast::cpp_entity &file);
+
+private:
+    void process_activities(const cppast::cpp_function &e);
+
+    // ctx allows to track current visitor context, e.g. current namespace
+    translation_unit_context ctx;
+};
 }
diff --git a/tests/t20001/.clang-uml b/tests/t20001/.clang-uml
index 2748c867..5a2b9c8c 100644
--- a/tests/t20001/.clang-uml
+++ b/tests/t20001/.clang-uml
@@ -14,7 +14,7 @@ diagrams:
     using_namespace:
       - clanguml::t20001
     start_from:
-      - usr: "c:@N@clanguml@N@t20001@F@tmain#"
+      - function: "clanguml::t20001::tmain()"
     plantuml:
       before:
         - "' t20001 test sequence diagram"
diff --git a/tests/t20001/test_case.h b/tests/t20001/test_case.h
index 1034f4c1..36027af3 100644
--- a/tests/t20001/test_case.h
+++ b/tests/t20001/test_case.h
@@ -18,7 +18,7 @@
 
 TEST_CASE("t20001", "[test-case][sequence]")
 {
-    auto [config, db] = load_config2("t20001");
+    auto [config, db] = load_config("t20001");
 
     auto diagram = config.diagrams["t20001_sequence"];
 
@@ -49,6 +49,7 @@ TEST_CASE("t20001", "[test-case][sequence]")
     REQUIRE_THAT(puml, HasCall("B", "A", "log_result"));
     REQUIRE_THAT(puml, HasCallWithResponse("B", "A", "add3"));
     REQUIRE_THAT(puml, HasCall("A", "add"));
+    REQUIRE_THAT(puml, !HasCall("A", "detail::C", "add"));
 
     save_puml(
         "./" + config.output_directory + "/" + diagram->name + ".puml", puml);
diff --git a/tests/test_cases.cc b/tests/test_cases.cc
index ab49b08b..999f6828 100644
--- a/tests/test_cases.cc
+++ b/tests/test_cases.cc
@@ -41,7 +41,7 @@ std::pair<clanguml::config::config, compilation_database> load_config2(
 }
 
 clanguml::sequence_diagram::model::diagram generate_sequence_diagram(
-    compilation_database &db,
+    cppast::libclang_compilation_database &db,
     std::shared_ptr<clanguml::config::diagram> diagram)
 {
     auto diagram_model =