Properly handle libclang diagnostics

include/cppast/diagnostic.hpp

@@ -26,13 +26,19 @@ namespace cppast
         }
 
         /// \returns A source location where only file and line information is available.
-        static source_location make(std::string file, unsigned line)
+        static source_location make_file(std::string file, unsigned line)
         {
             return {type_safe::nullopt, std::move(file), line};
         }
 
+        /// \returns A source location where only the file is available.
+        static source_location make_file(std::string file)
+        {
+            return {type_safe::nullopt, std::move(file), type_safe::nullopt};
+        }
+
         /// \returns A source location where only the entity name is available.
-        static source_location make(std::string entity)
+        static source_location make_entity(std::string entity)
         {
             return {std::move(entity), type_safe::nullopt, type_safe::nullopt};
         }

include/cppast/parser.hpp

@@ -5,6 +5,8 @@
 #ifndef CPPAST_PARSER_HPP_INCLUDED
 #define CPPAST_PARSER_HPP_INCLUDED
 
+#include <atomic>
+
 #include <cppast/compile_config.hpp>
 #include <cppast/cpp_file.hpp>
 
@@ -19,7 +21,10 @@ namespace cppast
     class diagnostic_logger
     {
     public:
-        diagnostic_logger() noexcept                = default;
+        diagnostic_logger() noexcept : error_(false)
+        {
+        }
+
         diagnostic_logger(const diagnostic_logger&) = delete;
         diagnostic_logger& operator=(const diagnostic_logger&) = delete;
         virtual ~diagnostic_logger() noexcept                  = default;
@@ -27,13 +32,21 @@ namespace cppast
         /// \effects Logs the diagnostic by invoking the `do_log()` member function.
         /// \returns Whether or not the diagnostic was logged.
         /// \notes `source` points to a string literal that gives additional context to what generates the message.
-        bool log(const char* source, const diagnostic& d) const
+        bool log(const char* source, const diagnostic& d) const;
+
+        /// \returns Whether or not a diagnostic of [severity::error]() was logged.
+        /// \notes If an error happens, the parser will still continue to build the AST,
+        /// unless the error is critical
+        /// so the result will be incomplete if this function returns `true`.
+        bool error_logged() const noexcept
         {
-            return do_log(source, d);
+            return error_;
         }
 
     private:
         virtual bool do_log(const char* source, const diagnostic& d) const = 0;
+
+        mutable std::atomic<bool> error_;
     };
 
     /// A [cppast::diagnostic_logger]() that logs to `stderr`.

src/libclang/libclang_parser.cpp

@@ -93,7 +93,7 @@ struct libclang_parser::impl
 {
     detail::cxindex index;
 
-    impl() : index(clang_createIndex(1, 1))
+    impl() : index(clang_createIndex(0, 0)) // no diagnostic, other one is irrelevant
     {
     }
 };
@@ -117,7 +117,46 @@ namespace
         return args;
     }
 
-    detail::cxtranslation_unit get_cxunit(const detail::cxindex&         idx,
+    type_safe::optional<severity> get_severity(const CXDiagnostic& diag)
+    {
+        switch (clang_getDiagnosticSeverity(diag))
+        {
+        case CXDiagnostic_Ignored:
+        case CXDiagnostic_Note:
+        case CXDiagnostic_Warning:
+            // ignore those diagnostics
+            return type_safe::nullopt;
+
+        case CXDiagnostic_Error:
+            return severity::error;
+        case CXDiagnostic_Fatal:
+            return severity::critical;
+        }
+
+        DEBUG_UNREACHABLE(detail::assert_handler{});
+        return type_safe::nullopt;
+    }
+
+    void print_diagnostics(const diagnostic_logger& logger, const char* path,
+                           const CXTranslationUnit& tu)
+    {
+        auto no = clang_getNumDiagnostics(tu);
+        for (auto i = 0u; i != no; ++i)
+        {
+            auto diag = clang_getDiagnostic(tu, i);
+            auto sev  = get_severity(diag);
+            if (sev)
+            {
+                auto loc  = source_location::make_file(path); // line number won't help
+                auto text = detail::cxstring(clang_getDiagnosticSpelling(diag));
+
+                logger.log("libclang parser", diagnostic{text.c_str(), loc, sev.value()});
+            }
+        }
+    }
+
+    detail::cxtranslation_unit get_cxunit(const diagnostic_logger&       logger,
+                                          const detail::cxindex&         idx,
                                           const libclang_compile_config& config, const char* path,
                                           const std::string& source)
     {
@@ -155,6 +194,7 @@ namespace
                 throw libclang_error("clang_parseTranslationUnit: AST deserialization error");
             }
         }
+        print_diagnostics(logger, path, tu);
 
         return detail::cxtranslation_unit(tu);
     }
@@ -178,8 +218,8 @@ std::unique_ptr<cpp_file> libclang_parser::do_parse(const cpp_entity_index& idx,
 
     // preprocess + parse
     auto preprocessed = detail::preprocess(config, path.c_str(), logger());
-    auto tu           = get_cxunit(pimpl_->index, config, path.c_str(), preprocessed.source);
+    auto tu   = get_cxunit(logger(), pimpl_->index, config, path.c_str(), preprocessed.source);
-    auto file         = clang_getFile(tu.get(), path.c_str());
+    auto file = clang_getFile(tu.get(), path.c_str());
 
     cpp_file::builder builder(path);
     auto              preprocessed_iter = preprocessed.entities.begin();

src/libclang/parse_error.hpp

@@ -19,12 +19,12 @@ namespace cppast
     {
         inline source_location make_location(const CXCursor& cur)
         {
-            return source_location::make(get_display_name(cur).c_str());
+            return source_location::make_entity(get_display_name(cur).c_str());
         }
 
         inline source_location make_location(const CXType& type)
         {
-            return source_location::make(cxstring(clang_getTypeSpelling(type)).c_str());
+            return source_location::make_entity(cxstring(clang_getTypeSpelling(type)).c_str());
         }
 
         // thrown on a parsing error

src/libclang/type_parser.cpp

@@ -330,7 +330,7 @@ namespace
         {
             auto msg = detail::format("unexpected type of kind '",
                                       detail::get_type_kind_spelling(type).c_str(), "'");
-            auto location = source_location::make(get_type_spelling(type).c_str());
+            auto location = source_location::make_entity(get_type_spelling(type).c_str());
             context.logger->log("libclang parser", diagnostic{msg, location, severity::warning});
         }
         // fallthrough

src/parser.cpp

@@ -11,6 +11,13 @@
 
 using namespace cppast;
 
+bool diagnostic_logger::log(const char* source, const diagnostic& d) const
+{
+    if (d.severity == severity::error)
+        error_ = true;
+    return do_log(source, d);
+}
+
 bool stderr_diagnostic_logger::do_log(const char* source, const diagnostic& d) const
 {
     std::fprintf(stderr, "[%s] [%s] %s %s\n", source, to_string(d.severity),

test/cpp_function.cpp

@@ -202,7 +202,7 @@ struct foo
 {
     static void a();
 
-    static int b() noexcept {}
+    static int b() noexcept { return 0; }
 
     static constexpr char c() = delete;
 };