Standalone MIRI (and mmir codegen) - Support external functions

3 files changed, 47 insertions, 3 deletions

diff --git a/src/trans/codegen_mmir.cpp b/src/trans/codegen_mmir.cpp
index 345a5703..703ef44d 100644
--- a/src/trans/codegen_mmir.cpp
+++ b/src/trans/codegen_mmir.cpp
@@ -796,6 +796,30 @@ namespace
 
             m_mir_res = nullptr;
         }
+        void emit_function_ext(const ::HIR::Path& p, const ::HIR::Function& item, const Trans_Params& params) override
+        {
+            ::MIR::Function empty_fcn;
+            ::MIR::TypeResolve  top_mir_res { sp, m_resolve, FMT_CB(ss, ss << "extern fn " << p;), ::HIR::TypeRef(), {}, empty_fcn };
+            m_mir_res = &top_mir_res;
+            TRACE_FUNCTION_F(p);
+
+            // If the function is a C external, emit as such
+            if( item.m_linkage.name != "" )
+            {
+                ::HIR::TypeRef  ret_type_tmp;
+                const auto& ret_type = monomorphise_fcn_return(ret_type_tmp, item, params);
+
+                m_of << "fn " << p << "(";
+                for(unsigned int i = 0; i < item.m_args.size(); i ++)
+                {
+                    if( i != 0 )    m_of << ", ";
+                    m_of << params.monomorph(m_resolve, item.m_args[i].second);
+                }
+                m_of << "): " << ret_type << " = \"" << item.m_linkage.name << "\":\"" << item.m_abi << "\";\n";
+            }
+
+            m_mir_res = nullptr;
+        }
         void emit_function_code(const ::HIR::Path& p, const ::HIR::Function& item, const Trans_Params& params, bool is_extern_def, const ::MIR::FunctionPointer& code) override
         {
             TRACE_FUNCTION_F(p);
diff --git a/tools/standalone_miri/module_tree.cpp b/tools/standalone_miri/module_tree.cpp
index 321eaad9..a457db8e 100644
--- a/tools/standalone_miri/module_tree.cpp
+++ b/tools/standalone_miri/module_tree.cpp
@@ -91,10 +91,24 @@ bool Parser::parse_one()
         {
             rv_ty = parse_type();
         }
-        auto body = parse_body();
+        
+        if( lex.consume_if('=') )
+        {
+            auto link_name = ::std::move(lex.check_consume(TokenClass::String).strval);
+            lex.check_consume(':');
+            auto abi = ::std::move(lex.check_consume(TokenClass::String).strval);
+            lex.check_consume(';');
 
-        auto p2 = p;
-        tree.functions.insert( ::std::make_pair(::std::move(p), Function { ::std::move(p2), ::std::move(arg_tys), rv_ty, ::std::move(body) }) );
+            auto p2 = p;
+            tree.functions.insert( ::std::make_pair(::std::move(p), Function { ::std::move(p2), ::std::move(arg_tys), rv_ty, {link_name, abi}, {} }) );
+        }
+        else
+        {
+            auto body = parse_body();
+
+            auto p2 = p;
+            tree.functions.insert( ::std::make_pair(::std::move(p), Function { ::std::move(p2), ::std::move(arg_tys), rv_ty, {}, ::std::move(body) }) );
+        }
     }
     else if( lex.consume_if("static") )
     {
diff --git a/tools/standalone_miri/module_tree.hpp b/tools/standalone_miri/module_tree.hpp
index dd302367..3489e77e 100644
--- a/tools/standalone_miri/module_tree.hpp
+++ b/tools/standalone_miri/module_tree.hpp
@@ -17,6 +17,12 @@ struct Function
     ::HIR::Path my_path;
     ::std::vector<::HIR::TypeRef>   args;
     ::HIR::TypeRef   ret_ty;
+    
+    // If `link_name` is non-empty, then the function is an external
+    struct {
+        ::std::string   link_name;
+        ::std::string   link_abi;
+    } external;
     ::MIR::Function m_mir;
 };