Codegen - Remove need for `-z muldefs`

4 files changed, 100 insertions, 17 deletions

diff --git a/src/expand/crate_tags.cpp b/src/expand/crate_tags.cpp
index ca5a98ce..e99f1aa2 100644
--- a/src/expand/crate_tags.cpp
+++ b/src/expand/crate_tags.cpp
@@ -52,7 +52,44 @@ public:
     }
 };
 
+class Decorator_Allocator:
+    public ExpandDecorator
+{
+public:
+    AttrStage stage() const override { return AttrStage::Pre; }
+
+    void handle(const Span& sp, const AST::MetaItem& mi, AST::Crate& crate) const override {
+        // TODO: Check for an existing allocator crate
+        crate.m_lang_items.insert(::std::make_pair( "mrustc-allocator", AST::Path("",{}) ));
+    }
+};
+class Decorator_PanicRuntime:
+    public ExpandDecorator
+{
+public:
+    AttrStage stage() const override { return AttrStage::Pre; }
+
+    void handle(const Span& sp, const AST::MetaItem& mi, AST::Crate& crate) const override {
+        // TODO: Check for an existing panic_runtime crate
+        crate.m_lang_items.insert(::std::make_pair( "mrustc-panic_runtime", AST::Path("",{}) ));
+    }
+};
+class Decorator_NeedsPanicRuntime:
+    public ExpandDecorator
+{
+public:
+    AttrStage stage() const override { return AttrStage::Pre; }
+
+    void handle(const Span& sp, const AST::MetaItem& mi, AST::Crate& crate) const override {
+        crate.m_lang_items.insert(::std::make_pair( "mrustc-needs_panic_runtime", AST::Path("",{}) ));
+    }
+};
+
 STATIC_DECORATOR("crate_type", Decorator_CrateType)
 STATIC_DECORATOR("crate_name", Decorator_CrateName)
 
+STATIC_DECORATOR("allocator", Decorator_Allocator)
+STATIC_DECORATOR("panic_runtime", Decorator_PanicRuntime)
+STATIC_DECORATOR("needs_panic_runtime", Decorator_NeedsPanicRuntime)
+
 
diff --git a/src/main.cpp b/src/main.cpp
index e6220fe6..36fa106e 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -328,19 +328,55 @@ int main(int argc, char *argv[])
 
         // Allocator and panic strategies
         CompilePhaseV("Implicit Crates", [&]() {
+            if( params.test_harness )
+            {
+                crate.load_extern_crate(Span(), "test");
+            }
             if( crate.m_crate_type == ::AST::Crate::Type::Executable || params.test_harness || crate.m_crate_type == ::AST::Crate::Type::ProcMacro )
             {
-                // TODO: Detect if an allocator crate is already present.
-                crate.load_extern_crate(Span(), "alloc_system");
-                crate.load_extern_crate(Span(), "panic_abort");
+                bool allocator_crate_loaded = false;
+                bool panic_runtime_loaded = false;
+                bool panic_runtime_needed = false;
+                for(const auto& ec : crate.m_extern_crates)
+                {
+                    ::std::ostringstream    ss;
+                    for(const auto& e : ec.second.m_hir->m_lang_items)
+                        ss << e << ",";
+                    DEBUG("Looking at lang items from " << ec.first << " : " << ss.str());
+                    if(ec.second.m_hir->m_lang_items.count("mrustc-allocator"))
+                    {
+                        if( allocator_crate_loaded ) {
+                            // TODO: Emit an error because there's multiple allocators loaded
+                        }
+                        allocator_crate_loaded = true;
+                    }
+                    if(ec.second.m_hir->m_lang_items.count("mrustc-panic_runtime"))
+                    {
+                        if( panic_runtime_loaded ) {
+                            // TODO: Emit an error because there's multiple allocators loaded
+                        }
+                        panic_runtime_loaded = true;
+                    }
+                    if(ec.second.m_hir->m_lang_items.count("mrustc-needs_panic_runtime"))
+                    {
+                        panic_runtime_needed = true;
+                    }
+                }
+                if( !allocator_crate_loaded )
+                {
+                    crate.load_extern_crate(Span(), "alloc_system");
+                }
+
+                if( panic_runtime_needed && !panic_runtime_loaded )
+                {
+                    // TODO: Get a panic method from the command line
+                    // - Fall back to abort by default, because mrustc doesn't do unwinding yet.
+                    crate.load_extern_crate(Span(), "panic_abort");
+                }
 
                 // - `mrustc-main` lang item default
                 crate.m_lang_items.insert(::std::make_pair( ::std::string("mrustc-main"), ::AST::Path("", {AST::PathNode("main")}) ));
             }
-            if( params.test_harness )
-            {
-                crate.load_extern_crate(Span(), "test");
-            }
             });
 
         // Resolve names to be absolute names (include references to the relevant struct/global/function)
diff --git a/src/trans/codegen.cpp b/src/trans/codegen.cpp
index a705c67b..b3244072 100644
--- a/src/trans/codegen.cpp
+++ b/src/trans/codegen.cpp
@@ -87,6 +87,7 @@ void Trans_Codegen(const ::std::string& outfile, const TransOptions& opt, const
         DEBUG("FUNCTION " << ent.first);
         assert( ent.second->ptr );
         const auto& fcn = *ent.second->ptr;
+        // Extern if there isn't any HIR
         bool is_extern = ! static_cast<bool>(fcn.m_code);
         if( fcn.m_code.m_mir ) {
             codegen->emit_function_proto(ent.first, fcn, ent.second->pp, is_extern);
diff --git a/src/trans/codegen_c.cpp b/src/trans/codegen_c.cpp
index f3274d68..393aba72 100644
--- a/src/trans/codegen_c.cpp
+++ b/src/trans/codegen_c.cpp
@@ -490,7 +490,6 @@ namespace {
                     {
                         args.push_back("-l"); args.push_back(path.c_str());
                     }
-                    args.push_back("-z"); args.push_back("muldefs");
                     args.push_back("-Wl,--gc-sections");
                 }
                 else
@@ -760,6 +759,10 @@ namespace {
         {
             ::MIR::TypeResolve  top_mir_res { sp, m_resolve, FMT_CB(ss, ss << "struct " << p;), ::HIR::TypeRef(), {}, *(::MIR::Function*)nullptr };
             m_mir_res = &top_mir_res;
+            bool is_vtable; {
+                const auto& lc = p.m_path.m_components.back();
+                is_vtable = (lc.size() > 7 && ::std::strcmp(lc.c_str() + lc.size() - 7, "#vtable") == 0);
+                };
 
             TRACE_FUNCTION_F(p);
             ::HIR::TypeRef  tmp;
@@ -796,11 +799,9 @@ namespace {
             m_of << "struct s_" << Trans_Mangle(p) << " {\n";
 
             // HACK: For vtables, insert the alignment and size at the start
+            if(is_vtable)
             {
-                const auto& lc = p.m_path.m_components.back();
-                if( lc.size() > 7 && ::std::strcmp(lc.c_str() + lc.size() - 7, "#vtable") == 0 ) {
-                    m_of << "\tVTABLE_HDR hdr;\n";
-                }
+                m_of << "\tVTABLE_HDR hdr;\n";
             }
 
             TU_MATCHA( (item.m_data), (e),
@@ -1222,7 +1223,7 @@ namespace {
             const auto& e = str.m_data.as_Tuple();
 
 
-            m_of << "struct e_" << Trans_Mangle(p) << " " << Trans_Mangle(path) << "(";
+            m_of << "static struct e_" << Trans_Mangle(p) << " " << Trans_Mangle(path) << "(";
             for(unsigned int i = 0; i < e.size(); i ++)
             {
                 if(i != 0)
@@ -1282,7 +1283,7 @@ namespace {
                 };
             // Crate constructor function
             const auto& e = item.m_data.as_Tuple();
-            m_of << "struct s_" << Trans_Mangle(p) << " " << Trans_Mangle(p) << "(";
+            m_of << "static struct s_" << Trans_Mangle(p) << " " << Trans_Mangle(p) << "(";
             for(unsigned int i = 0; i < e.size(); i ++)
             {
                 if(i != 0)
@@ -1683,10 +1684,13 @@ namespace {
                     auto fcn_p = p.clone();
                     fcn_p.m_data.as_UfcsKnown().item = call_fcn_name;
                     fcn_p.m_data.as_UfcsKnown().trait.m_path = trait_name.clone();
-                    emit_ctype(*te->m_rettype);
+
                     auto  arg_ty = ::HIR::TypeRef::new_unit();
                     for(const auto& ty : te->m_arg_types)
                         arg_ty.m_data.as_Tuple().push_back( ty.clone() );
+
+                    m_of << "static ";
+                    emit_ctype(*te->m_rettype);
                     m_of << " " << Trans_Mangle(fcn_p) << "("; emit_ctype(type, FMT_CB(ss, ss << "*ptr";)); m_of << ", "; emit_ctype(arg_ty, FMT_CB(ss, ss << "args";)); m_of << ") {\n";
                     m_of << "\treturn (*ptr)(";
                         for(unsigned int i = 0; i < te->m_arg_types.size(); i++)
@@ -1711,10 +1715,15 @@ namespace {
                 const auto& vtable_ref = m_crate.get_struct_by_path(sp, vtable_sp);
                 ::HIR::TypeRef  vtable_ty( ::HIR::GenericPath(mv$(vtable_sp), mv$(vtable_params)), &vtable_ref );
 
-                if( m_compiler == Compiler::Msvc )
+                // Weak link for vtables
+                switch(m_compiler)
                 {
-                    // Weak link for vtables
+                case Compiler::Gcc:
+                    m_of << "__attribute__((weak)) ";
+                    break;
+                case Compiler::Msvc:
                     m_of << "__declspec(selectany) ";
+                    break;
                 }
 
                 emit_ctype(vtable_ty);