Allow specifying an import module using @wasm #1305.

releasenotes.md

@@ -22,6 +22,7 @@
 - Ability of `vendor-fetch` to register the fetched dependencies in the project file.
 - Allow the "self" parameter to be $/# for macro methods.
 - Support compile time slicing of untyped lists.
+- Allow specifying an import module using `@wasm` #1305.
 
 ### Fixes
 - Issue where a lambda wasn't correctly registered as external. #1408

src/compiler/compiler_internal.h

@@ -345,6 +345,7 @@ typedef struct
 	const char *deprecated;
 	const char **links;
 	const char *section;
+	const char *wasm_module;
 	SourceSpan overload;
 } ResolvedAttrData;
 

src/compiler/copying.c

@@ -806,6 +806,7 @@ static ResolvedAttrData *copy_attrs_resolved(CopyStruct *c, ResolvedAttrData *da
 			.deprecated = data->deprecated,
 			.links = data->links,
 			.section = data->section,
+			.wasm_module = data->wasm_module
 	};
 	return copy;
 }

src/compiler/llvm_codegen.c

@@ -1183,6 +1183,10 @@ void llvm_append_function_attributes(GenContext *c, Decl *decl)
 	{
 		scratch_buffer_set_extern_decl_name(decl, true);
 		llvm_attribute_add_string(c, function, "wasm-import-name", scratch_buffer_to_string(), -1);
+		if (decl->attrs_resolved && decl->attrs_resolved->wasm_module)
+		{
+			llvm_attribute_add_string(c, function, "wasm-import-module", decl->attrs_resolved->wasm_module, -1);
+		}
 	}
 	if (decl->alignment != type_abi_alignment(decl->type))
 	{

src/compiler/sema_decls.c

@@ -2419,10 +2419,9 @@ static bool sema_analyse_attribute(SemaContext *context, ResolvedAttrData *attr_
 
 	// No attribute has more than one argument right now.
 	unsigned args = vec_size(attr->exprs);
-	if (args > 1 && type != ATTRIBUTE_LINK && type != ATTRIBUTE_TAG)
+	if (args > 1 && type != ATTRIBUTE_LINK && type != ATTRIBUTE_TAG && type != ATTRIBUTE_WASM)
 	{
-		SEMA_ERROR(attr->exprs[1], "Too many arguments for the attribute.");
-		return false;
+		RETURN_SEMA_ERROR(attr->exprs[1], "Too many arguments for the attribute.");
 	}
 	Expr *expr = args ? attr->exprs[0] : NULL;
 
@@ -2554,6 +2553,41 @@ static bool sema_analyse_attribute(SemaContext *context, ResolvedAttrData *attr_
 				decl->alignment = (AlignSize)align;
 				return true;
 			}
+		case ATTRIBUTE_WASM:
+			if (args > 2) RETURN_SEMA_ERROR(attr->exprs[2], "Too many arguments to '@wasm', expected 0, 1 or 2 arguments");
+			decl->is_export = true;
+			if (context->unit->module->is_generic)
+			{
+				RETURN_SEMA_ERROR(attr, "'@wasm' is not allowed in generic modules.");
+			}
+			if (args == 0) return true;
+			if (decl->has_extname)
+			{
+				RETURN_SEMA_ERROR(expr, "An external name is already defined, please use '@wasm` without an argument.");
+			}
+			if (args == 2)
+			{
+				if (!decl->is_extern)
+				{
+					RETURN_SEMA_ERROR(expr, "Specifying a wasm import module name is only valid for extern declarations.");
+				}
+				Expr *module = expr;
+				expr = attr->exprs[1];
+				if (!sema_analyse_expr(context, module)) return false;
+				if (!expr_is_const_string(module))
+				{
+					RETURN_SEMA_ERROR(module, "Expected a constant string value as argument.");
+				}
+				attr_data->wasm_module = module->const_expr.bytes.ptr;
+				if (!sema_analyse_expr(context, expr)) return false;
+				if (!expr_is_const_string(expr))
+				{
+					RETURN_SEMA_ERROR(expr, "Expected a constant string value as argument.");
+				}
+				decl->extname = expr->const_expr.bytes.ptr;
+				decl->has_extname = true;
+			}
+			return true;
 		case ATTRIBUTE_EXPORT:
 			if (context->unit->module->is_generic)
 			{
@@ -2729,9 +2763,6 @@ static bool sema_analyse_attribute(SemaContext *context, ResolvedAttrData *attr_
 			}
 			decl->is_weak = true;
 			break;
-		case ATTRIBUTE_WASM:
-			decl->is_export = true;
-			break;
 		case ATTRIBUTE_NAKED:
 			assert(domain == ATTR_FUNC);
 			decl->func_decl.attr_naked = true;
@@ -2915,7 +2946,7 @@ static bool sema_analyse_attributes(SemaContext *context, Decl *decl, Attr **att
 	if (!sema_analyse_attributes_inner(context, &data, decl, attrs, domain, NULL, erase_decl)) return false;
 	if (*erase_decl) return true;
 	decl->resolved_attributes = true;
-	if (data.tags || data.deprecated || data.links || data.section || data.overload.row)
+	if (data.tags || data.deprecated || data.links || data.section || data.overload.row || data.wasm_module )
 	{
 		ResolvedAttrData *copy = MALLOCS(ResolvedAttrData);
 		*copy = data;

test/test_suite/attributes/attributes_repeat_param.c3t

@@ -0,0 +1,26 @@
+// #target: macos-aarch64
+module test;
+
+def @Test(x) = { @extern("Foo" +++ x) };
+
+fn void hello_world() @Test("Megaman")
+{}
+
+fn void ello_world() @Test("Pegasus")
+{}
+
+fn int main()
+{
+	hello_world();
+	ello_world();
+	return 0;
+}
+
+/* #expect: test.ll
+
+define i32 @main() #0 {
+entry:
+  call void @FooMegaman()
+  call void @FooPegasus()
+  ret i32 0
+}

test/test_suite/attributes/wasm_import.c3t

@@ -0,0 +1,8 @@
+// #target: wasm32
+module test;
+extern fn void test() @wasm("hello", "world");
+
+/* #expect: test.ll
+
+declare void @world() #0
+attributes #0 = { nounwind uwtable "no-trapping-math"="true" "stack-protector-buffer-size"="8" "wasm-export-name"="world" "wasm-import-module"="hello" "wasm-import-name"="world" }

test/test_suite/attributes/wasm_module.c3

@@ -0,0 +1,5 @@
+
+fn void test() @wasm("hello", "world") { } // #error: Specifying a wasm import module
+extern fn void test2() @wasm("a", "b", "c"); // #error: Too many arguments to
+extern fn void test3() @extern("hello") @wasm("a"); // #error: An external name
+extern fn void test4() @extern("hello") @wasm("a", "b"); // #error: An external name