Use atexit to fix finalizers on Windows #1361.

releasenotes.md

@@ -24,6 +24,7 @@
 - Correct '.so' suffix on dynamic libraries on Linux.
 - Fix bug where inline index access to array in a struct would crash the compiler.
 - Asserts are now correctly included and traced in when running tests.
+- Use atexit to fix finalizers on Windows #1361.
 
 ### Stdlib changes
 - Additional init functions for hashmap.

resources/examples/ls.c3

@@ -2,8 +2,8 @@ import std::io;
 
 fn void main()
 {
-	Path path = path::getcwd()!!;
-	foreach (i, p : path::ls(path)!!)
+	Path path = path::new_cwd()!!;
+	foreach (i, p : path::new_ls(path)!!)
 	{
 		io::printfn("%02d %s", i, p.str_view());
 	}

resources/msvc_stack.c3

@@ -2,6 +2,12 @@ module test;
 import std::io;
 import std::collections::map;
 import std::os;
+import libc;
+
+fn void bye() @finalizer
+{
+	libc::puts("Bye from finalizer!");
+}
 
 fn void test1()
 {

src/compiler/llvm_codegen_function.c

@@ -406,10 +406,26 @@ void llvm_emit_function_body(GenContext *c, Decl *decl)
 	DEBUG_LOG("Generating function %s.", decl->name);
 	if (decl->func_decl.attr_dynamic) vec_add(c->dynamic_functions, decl);
 	assert(decl->backend_ref);
-	if (decl->func_decl.attr_init || decl->func_decl.attr_finalizer)
+	if (decl->func_decl.attr_init || (decl->func_decl.attr_finalizer && compiler.platform.object_format == OBJ_FORMAT_MACHO))
 	{
 		llvm_append_xxlizer(c, decl->func_decl.priority, decl->func_decl.attr_init, decl->backend_ref);
 	}
+	if (decl->func_decl.attr_finalizer && compiler.platform.object_format != OBJ_FORMAT_MACHO)
+	{
+		LLVMValueRef atexit = LLVMGetNamedFunction(c->module, "atexit");
+		if (!atexit) atexit = LLVMAddFunction(c->module, "atexit", c->atexit_type);
+		scratch_buffer_clear();
+		scratch_buffer_append(".__c3_atexit_");
+		scratch_buffer_set_extern_decl_name(decl, false);
+		LLVMValueRef func = LLVMAddFunction(c->module, scratch_buffer_to_string(), c->xtor_func_type);
+
+		LLVMBuilderRef builder = llvm_create_function_entry(c, func, NULL);
+		LLVMValueRef args[1] = { decl->backend_ref };
+		LLVMBuildCall2(builder, c->atexit_type, atexit, args, 1, "");
+		LLVMBuildRetVoid(builder);
+		LLVMDisposeBuilder(builder);
+		llvm_append_xxlizer(c, decl->func_decl.priority, true, func);
+	}
 	llvm_emit_body(c,
 	               decl->backend_ref,
 	               type_get_resolved_prototype(decl->type),

src/compiler/llvm_codegen_internal.h

@@ -97,6 +97,7 @@ typedef struct GenContext_
 	LLVMTypeRef bool_type;
 	LLVMTypeRef byte_type;
 	LLVMTypeRef introspect_type;
+	LLVMTypeRef atexit_type;
 	LLVMTypeRef fault_type;
 	LLVMTypeRef size_type;
 	LLVMTypeRef typeid_type;

src/compiler/llvm_codegen_module.c

@@ -131,13 +131,15 @@ void gencontext_begin_module(GenContext *c)
 	c->ptr_type = LLVMPointerType(c->byte_type, 0);
 	c->size_type = llvm_get_type(c, type_usz);
 	c->typeid_type = llvm_get_type(c, type_typeid);
+	LLVMTypeRef void_type = LLVMVoidTypeInContext(c->context);
 	LLVMTypeRef dtable_type[3] = { c->ptr_type, c->ptr_type, c->ptr_type };
 	c->dtable_type = LLVMStructTypeInContext(c->context, dtable_type, 3, false);
 	c->chars_type = llvm_get_type(c, type_chars);
 	LLVMTypeRef ctor_type[3] = { LLVMInt32TypeInContext(c->context), c->ptr_type, c->ptr_type };
 	c->xtor_entry_type = LLVMStructTypeInContext(c->context, ctor_type, 3, false);
-	c->xtor_func_type = LLVMFunctionType(LLVMVoidTypeInContext(c->context), NULL, 0, false);
+	c->xtor_func_type = LLVMFunctionType(void_type, NULL, 0, false);
 	c->introspect_type = create_introspection_type(c);
+	c->atexit_type = LLVMFunctionType(void_type, &c->ptr_type, 1, false);
 	c->fault_type = create_fault_type(c);
 	c->memcmp_function = NULL;
 	LLVMTypeRef memcmp_types[3] = {c->ptr_type, c->ptr_type, c->size_type };

test/test_suite/initialize/initialize_finalize.c3t

@@ -31,8 +31,7 @@ fn void shutdown() @finalizer
 
 /* #expect: test.ll
 
-@llvm.global_ctors = appending global [4 x { i32, ptr, ptr }] [{ i32, ptr, ptr } { i32 300, ptr @test.startup2, ptr null }, { i32, ptr, ptr } { i32 65535, ptr @test.start_main, ptr null }, { i32, ptr, ptr } { i32 200, ptr @test.startup1, ptr null }, { i32, ptr, ptr } { i32 65535, ptr @test.empty_startup, ptr null }]
-@llvm.global_dtors = appending global [1 x { i32, ptr, ptr }] [{ i32, ptr, ptr } { i32 65535, ptr @test.shutdown, ptr null }]
+@llvm.global_ctors = appending global [5 x { i32, ptr, ptr }] [{ i32, ptr, ptr } { i32 300, ptr @test.startup2, ptr null }, { i32, ptr, ptr } { i32 65535, ptr @test.start_main, ptr null }, { i32, ptr, ptr } { i32 200, ptr @test.startup1, ptr null }, { i32, ptr, ptr } { i32 65535, ptr @test.empty_startup, ptr null }, { i32, ptr, ptr } { i32 65535, ptr @.__c3_atexit_test.shutdown, ptr null }]
 
 define void @test.startup2() #0 {
 entry:
@@ -61,3 +60,9 @@ entry:
   call void @puts(ptr @.str.4)
   ret void
 }
+
+define void @.__c3_atexit_test.shutdown() {
+entry:
+  call void @atexit(ptr @test.shutdown)
+  ret void
+}