Cache the paddding filler type

src/llvm_backend.hpp

@@ -137,6 +137,12 @@ enum lbFunctionPassManagerKind {
 	lbFunctionPassManager_COUNT
 };
 
+struct lbPadType {
+	i64 padding;
+	i64 padding_align;
+	LLVMTypeRef type;
+};
+
 struct lbModule {
 	LLVMModuleRef mod;
 	LLVMContextRef ctx;
@@ -199,6 +205,9 @@ struct lbModule {
 	PtrMap<Ast *, lbAddr> exact_value_compound_literal_addr_map; // Key: Ast_CompoundLit
 
 	LLVMPassManagerRef function_pass_managers[lbFunctionPassManager_COUNT];
+
+	BlockingMutex pad_types_mutex;
+	Array<lbPadType> pad_types;
 };
 
 struct lbEntityCorrection {

src/llvm_backend_general.cpp

@@ -91,6 +91,9 @@ gb_internal void lb_init_module(lbModule *m, Checker *c) {
 	map_init(&m->map_cell_info_map, 0);
 	map_init(&m->exact_value_compound_literal_addr_map, 1024);
 
+	array_init(&m->pad_types, heap_allocator());
+
+
 	m->const_dummy_builder = LLVMCreateBuilderInContext(m->ctx);
 
 }

src/llvm_backend_utility.cpp

@@ -1003,6 +1003,21 @@ gb_internal i32 lb_convert_struct_index(lbModule *m, Type *t, i32 index) {
 }
 
 gb_internal LLVMTypeRef lb_type_padding_filler(lbModule *m, i64 padding, i64 padding_align) {
+	MUTEX_GUARD(&m->pad_types_mutex);
+	if (padding % padding_align == 0) {
+		for (auto pd : m->pad_types) {
+			if (pd.padding == padding && pd.padding_align == padding_align) {
+				return pd.type;
+			}
+		}
+	} else {
+		for (auto pd : m->pad_types) {
+			if (pd.padding == padding && pd.padding_align == 1) {
+				return pd.type;
+			}
+		}
+	}
+
 	// NOTE(bill): limit to `[N x u64]` to prevent ABI issues
 	padding_align = gb_clamp(padding_align, 1, 8);
 	if (padding % padding_align == 0) {
@@ -1016,13 +1031,19 @@ gb_internal LLVMTypeRef lb_type_padding_filler(lbModule *m, i64 padding, i64 pad
 		}
 		
 		GB_ASSERT_MSG(elem != nullptr, "Invalid lb_type_padding_filler padding and padding_align: %lld", padding_align);
+
+		LLVMTypeRef type = nullptr;
 		if (len != 1) {
-			return llvm_array_type(elem, len);
+			type = llvm_array_type(elem, len);
 		} else {
-			return elem;
+			type = elem;
 		}
+		array_add(&m->pad_types, lbPadType{padding, padding_align, type});
+		return type;
 	} else {
-		return llvm_array_type(lb_type(m, t_u8), padding);
+		LLVMTypeRef type = llvm_array_type(lb_type(m, t_u8), padding);
+		array_add(&m->pad_types, lbPadType{padding, 1, type});
+		return type;
 	}
 }