Thunks/gen: Move diagnostic marshaling helper to a dedicated header

ThunkLibs/Generator/diagnostics.h

@@ -0,0 +1,60 @@
+#pragma once
+
+#include <clang/AST/ASTContext.h>
+#include <clang/Basic/Diagnostic.h>
+#include <clang/Basic/SourceLocation.h>
+
+#include <utility>
+#include <vector>
+
+struct ClangDiagnosticAsException {
+    std::pair<clang::SourceLocation, unsigned> diagnostic;
+
+    std::vector<ClangDiagnosticAsException> notes;
+
+    // List of callbacks that add an argument to a clang::DiagnosticBuilder
+    std::vector<std::function<void(clang::DiagnosticBuilder&)>> args;
+
+    ClangDiagnosticAsException& AddString(std::string str) {
+        args.push_back([arg=std::move(str)](clang::DiagnosticBuilder& db) {
+            db.AddString(arg);
+        });
+        return *this;
+    }
+
+    ClangDiagnosticAsException& AddTaggedVal(clang::QualType type) {
+        args.push_back([val=type](clang::DiagnosticBuilder& db) {
+            db.AddTaggedVal(reinterpret_cast<uintptr_t>(val.getAsOpaquePtr()), clang::DiagnosticsEngine::ak_qualtype);
+        });
+        return *this;
+    }
+
+    ClangDiagnosticAsException& addNote(ClangDiagnosticAsException diagnostic) {
+        notes.push_back(std::move(diagnostic));
+        return *this;
+    }
+
+    void Report(clang::DiagnosticsEngine& diagnostics) const {
+        {
+            auto builder = diagnostics.Report(diagnostic.first, diagnostic.second);
+            for (auto& arg_appender : args) {
+                arg_appender(builder);
+            }
+        }
+        for (auto& note : notes) {
+            note.Report(diagnostics);
+        }
+    }
+};
+
+// Helper class to build a custom DiagID from the given message and store it in a throwable object
+struct ErrorReporter {
+    clang::ASTContext& context;
+
+    template<std::size_t N>
+    [[nodiscard]] ClangDiagnosticAsException operator()(clang::SourceLocation loc, const char (&message)[N],
+                                                        clang::DiagnosticsEngine::Level level = clang::DiagnosticsEngine::Error) {
+        auto id = context.getDiagnostics().getCustomDiagID(level, message);
+        return { std::pair(loc, id) };
+    }
+};

ThunkLibs/Generator/gen.cpp

@@ -1,6 +1,8 @@
 #include "clang/AST/RecursiveASTVisitor.h"
 #include "clang/Frontend/CompilerInstance.h"
 
+#include "diagnostics.h"
+
 #include <fstream>
 #include <numeric>
 #include <iostream>
@@ -103,25 +105,6 @@ struct NamespaceInfo {
 
 static std::vector<clang::DeclContext*> decl_contexts;
 
-struct ClangDiagnosticAsException {
-    std::pair<clang::SourceLocation, unsigned> diagnostic;
-
-    void Report(clang::DiagnosticsEngine& diagnostics) const {
-        diagnostics.Report(diagnostic.first, diagnostic.second);
-    }
-};
-
-// Helper class to build a custom DiagID from the given message and store it in a throwable object
-struct ErrorReporter {
-    clang::ASTContext& context;
-
-    template<std::size_t N>
-    [[nodiscard]] ClangDiagnosticAsException operator()(clang::SourceLocation loc, const char (&message)[N]) {
-        auto id = context.getDiagnostics().getCustomDiagID(clang::DiagnosticsEngine::Error, message);
-        return { std::pair(loc, id) };
-    }
-};
-
 struct NamespaceAnnotations {
     std::optional<unsigned> version;
     std::optional<std::string> load_host_endpoint_via;