Expand/Trans - Better handling of #[panic_implementation]

4 files changed, 52 insertions, 7 deletions

diff --git a/src/ast/ast.hpp b/src/ast/ast.hpp
index bfef9cff..a6c06e76 100644
--- a/src/ast/ast.hpp
+++ b/src/ast/ast.hpp
@@ -51,6 +51,7 @@ enum eItemType
     ITEM_ENUM,
     ITEM_UNION,
     ITEM_FN,
+    ITEM_EXTERN_FN,
     ITEM_STATIC,
 };
 
diff --git a/src/expand/lang_item.cpp b/src/expand/lang_item.cpp
index 8dd481f3..035bd5bd 100644
--- a/src/expand/lang_item.cpp
+++ b/src/expand/lang_item.cpp
@@ -99,12 +99,16 @@ void handle_lang_item(const Span& sp, AST::Crate& crate, const AST::Path& path,
     // Statics
     else if( name == "msvc_try_filter" ) { }
 
+    // Extern functions
+    else if( name == "panic_impl" ) {
+    }
+    else if( name == "oom" ) {
+    }
+
     // Functions
     else if( name == "panic" ) { }
     else if( name == "panic_bounds_check" ) { }
-    else if( name == "panic_fmt" ) {
-
-    }
+    else if( name == "panic_fmt" ) { }
     else if( name == "str_eq" ) { }
     else if( name == "drop_in_place" ) { }
     else if( name == "align_offset" ) { }
@@ -148,6 +152,12 @@ void handle_lang_item(const Span& sp, AST::Crate& crate, const AST::Path& path,
         ERROR(sp, E0000, "Unknown language item '" << name << "'");
     }
 
+    if( type == AST::ITEM_EXTERN_FN )
+    {
+        // TODO: This should force a specific link name instead
+        return ;
+    }
+
     auto rv = crate.m_lang_items.insert( ::std::make_pair( name, ::AST::Path(path) ) );
     if( !rv.second ) {
         const auto& other_path = rv.first->second;
@@ -177,7 +187,7 @@ public:
                 handle_lang_item(sp, crate, path, attr.string(), AST::ITEM_FN);
             }
             else {
-                //handle_lang_item(sp, crate, path, attr.string(), AST::ITEM_EXTERN_FN);
+                handle_lang_item(sp, crate, path, attr.string(), AST::ITEM_EXTERN_FN);
             }
             ),
         (Static,
@@ -280,9 +290,30 @@ public:
     }
 };
 
+class Decorator_PanicImplementation:
+    public ExpandDecorator
+{
+public:
+    AttrStage stage() const override { return AttrStage::Post; }
+    void handle(const Span& sp, const AST::Attribute& attr, AST::Crate& crate, const AST::Path& path, AST::Module& mod, AST::Item& i) const override
+    {
+        TU_IFLET(::AST::Item, i, Function, e,
+            auto rv = crate.m_lang_items.insert(::std::make_pair( ::std::string("mrustc-panic_implementation"), ::AST::Path(path) ));
+            if( !rv.second )
+            {
+                const auto& other_path = rv.first->second;
+                ERROR(sp, E0000, "Duplicate definition of #[panic_implementation] - " << other_path << " and " << path);
+            }
+        )
+        else {
+            ERROR(sp, E0000, "#[panic_implementation] on non-function " << path);
+        }
+    }
+};
 
 STATIC_DECORATOR("lang", Decorator_LangItem)
 STATIC_DECORATOR("main", Decorator_Main);
 STATIC_DECORATOR("start", Decorator_Start);
+STATIC_DECORATOR("panic_implementation", Decorator_PanicImplementation);
 
 
diff --git a/src/expand/mod.cpp b/src/expand/mod.cpp
index e3cef375..d9a19b2c 100644
--- a/src/expand/mod.cpp
+++ b/src/expand/mod.cpp
@@ -55,14 +55,22 @@ void ExpandDecorator::unexpected(const Span& sp, const AST::Attribute& mi, const
 
 void Expand_Attr(const Span& sp, const ::AST::Attribute& a, AttrStage stage,  ::std::function<void(const Span& sp, const ExpandDecorator& d,const ::AST::Attribute& a)> f)
 {
+    bool found = false;
     for( auto& d : g_decorators ) {
         if( a.name() == d.first ) {
             DEBUG("#[" << d.first << "] " << (int)d.second->stage() << "-" << (int)stage);
             if( d.second->stage() == stage ) {
                 f(sp, *d.second, a);
+                // TODO: Early return?
+                // TODO: Annotate the attribute as having been handled
             }
+            found = true;
         }
     }
+    if( !found ) {
+        // TODO: Create no-op handlers for a whole heap of attributes
+        //WARNING(sp, W0000, "Unknown attribute " << a.name());
+    }
 }
 void Expand_Attrs(/*const */::AST::AttributeList& attrs, AttrStage stage,  ::std::function<void(const Span& sp, const ExpandDecorator& d,const ::AST::Attribute& a)> f)
 {
diff --git a/src/trans/codegen_c.cpp b/src/trans/codegen_c.cpp
index 9af87d47..c148c51f 100644
--- a/src/trans/codegen_c.cpp
+++ b/src/trans/codegen_c.cpp
@@ -713,10 +713,14 @@ namespace {
                     }
 
                     // TODO: Bind `panic_impl` lang item to the item tagged with `panic_implementation`
+                    m_of << "uint32_t panic_impl(uintptr_t payload) {";
+                    const auto& panic_impl_path = m_crate.get_lang_item_path(Span(), "mrustc-panic_implementation");
+                    m_of << "extern uint32_t " << Trans_Mangle(panic_impl_path) << "(uintptr_t payload);";
+                    m_of << "return " << Trans_Mangle(panic_impl_path) << "(payload);";
+                    m_of << "}\n";
                     // TODO: Bind `oom` lang item to the item tagged with `alloc_error_handler`
                     // - Can do this in enumerate/auto_impls instead, for better iteraction with enum
                     // XXX: HACK HACK HACK - This only works with libcore/libstd's current layout
-                    m_of << "uint32_t panic_impl(uintptr_t payload) { extern uint32_t __rust_start_panic(uintptr_t payload); return __rust_start_panic(payload); }\n";
                     m_of << "struct s__ZN4core5alloc6Layout_A { uintptr_t a, b; };\n";
                     m_of << "void oom_impl(struct s__ZN4core5alloc6Layout_A l) { extern void _ZN3std5alloc8rust_oom(struct s__ZN4core5alloc6Layout_A l); _ZN3std5alloc8rust_oom(l); }\n";
                 }
@@ -4475,7 +4479,7 @@ namespace {
                 {
                 case Compiler::Gcc:
                     m_of << "{ ";
-                    m_of << " jmp_buf jmpbuf; mrustc_panic_target = &jmpbuf;";
+                    m_of << " jmp_buf jmpbuf, *old = mrustc_panic_target; mrustc_panic_target = &jmpbuf;";
                     m_of << " if(setjmp(jmpbuf)) {";
                     // NOTE: gcc unwind has a pointer as its `local_ptr` parameter
                     m_of << " *(void**)("; emit_param(e.args.at(2)); m_of << ") = mrustc_panic_value;";
@@ -4493,7 +4497,8 @@ namespace {
                 case Compiler::Gcc:
                     m_of << ";";
                     m_of << " }";
-                    m_of << " mrustc_panic_target = NULL;";
+                    m_of << " if(mrustc_panic_target != &jmpbuf) { abort(); }";
+                    m_of << " mrustc_panic_target = old;";
                     m_of << " }";
                     break;
                 default: