implement comptime struct fields

src/all_types.hpp

@@ -1263,6 +1263,7 @@ struct TypeStructField {
     uint32_t bit_offset_in_host; // offset from the memory at gen_index
     uint32_t host_int_bytes; // size of host integer
     uint32_t align;
+    bool is_comptime;
 };
 
 enum ResolveStatus {

src/analyze.cpp

@@ -2788,6 +2788,9 @@ static Error resolve_struct_zero_bits(CodeGen *g, ZigType *struct_type) {
         type_struct_field->src_index = i;
         type_struct_field->gen_index = SIZE_MAX;
 
+        if (type_struct_field->is_comptime)
+            continue;
+
         switch (type_val_resolve_requires_comptime(g, field_type_val)) {
             case ReqCompTimeYes:
                 struct_type->data.structure.requires_comptime = true;
@@ -7987,8 +7990,9 @@ static void resolve_llvm_types_struct(CodeGen *g, ZigType *struct_type, ResolveS
     // inserting padding bytes where LLVM would do it automatically.
     size_t llvm_struct_abi_align = 0;
     for (size_t i = 0; i < field_count; i += 1) {
-        ZigType *field_type = struct_type->data.structure.fields[i]->type_entry;
+        TypeStructField *field = struct_type->data.structure.fields[i];
-        if (!type_has_bits(field_type))
+        ZigType *field_type = field->type_entry;
+        if (field->is_comptime || !type_has_bits(field_type))
             continue;
         LLVMTypeRef field_llvm_type = get_llvm_type(g, field_type);
         size_t llvm_field_abi_align = LLVMABIAlignmentOfType(g->target_data_ref, field_llvm_type);
@@ -7999,7 +8003,7 @@ static void resolve_llvm_types_struct(CodeGen *g, ZigType *struct_type, ResolveS
         TypeStructField *field = struct_type->data.structure.fields[i];
         ZigType *field_type = field->type_entry;
 
-        if (!type_has_bits(field_type)) {
+        if (field->is_comptime || !type_has_bits(field_type)) {
             field->gen_index = SIZE_MAX;
             continue;
         }

src/ir.cpp

@@ -655,6 +655,10 @@ static ZigValue *const_ptr_pointee_unchecked(CodeGen *g, ZigValue *const_val) {
     if (isf != nullptr) {
         TypeStructField *field = find_struct_type_field(isf->inferred_struct_type, isf->field_name);
         assert(field != nullptr);
+        if (field->is_comptime) {
+            assert(field->init_val != nullptr);
+            return field->init_val;
+        }
         assert(const_val->data.x_ptr.special == ConstPtrSpecialRef);
         ZigValue *struct_val = const_val->data.x_ptr.data.ref.pointee;
         return struct_val->data.x_struct.fields[field->src_index];
@@ -17373,6 +17377,13 @@ static IrInstruction *ir_analyze_store_ptr(IrAnalyze *ira, IrInstruction *source
         field->type_val = create_const_type(ira->codegen, field->type_entry);
         field->src_index = old_field_count;
         field->decl_node = uncasted_value->source_node;
+        if (instr_is_comptime(uncasted_value)) {
+            ZigValue *uncasted_val = ir_resolve_const(ira, uncasted_value, UndefOk);
+            field->is_comptime = true;
+            field->init_val = create_const_vals(1);
+            copy_const_val(field->init_val, uncasted_val);
+            return ir_const_void(ira, source_instr);
+        }
 
         ZigType *struct_ptr_type = get_pointer_to_type(ira->codegen, isf->inferred_struct_type, false);
         IrInstruction *casted_ptr;
@@ -19510,6 +19521,11 @@ static IrInstruction *ir_analyze_struct_field_ptr(IrAnalyze *ira, IrInstruction
     ZigType *field_type = resolve_struct_field_type(ira->codegen, field);
     if (field_type == nullptr)
         return ira->codegen->invalid_instruction;
+    if (field->is_comptime) {
+        IrInstruction *elem = ir_const(ira, source_instr, field_type);
+        copy_const_val(elem->value, field->init_val);
+        return ir_get_ref(ira, source_instr, elem, true, false);
+    }
     switch (type_has_one_possible_value(ira->codegen, field_type)) {
         case OnePossibleValueInvalid:
             return ira->codegen->invalid_instruction;
@@ -21716,6 +21732,10 @@ static IrInstruction *ir_analyze_instruction_container_init_list(IrAnalyze *ira,
             for (size_t i = 0; i < const_ptrs.length; i += 1) {
                 IrInstruction *elem_result_loc = const_ptrs.at(i);
                 assert(elem_result_loc->value->special == ConstValSpecialStatic);
+                if (elem_result_loc->value->type->data.pointer.inferred_struct_field != nullptr) {
+                    // This field will be generated comptime; no need to do this.
+                    continue;
+                }
                 IrInstruction *deref = ir_get_deref(ira, elem_result_loc, elem_result_loc, nullptr);
                 elem_result_loc->value->special = ConstValSpecialRuntime;
                 ir_analyze_store_ptr(ira, elem_result_loc, elem_result_loc, deref, false);

test/stage1/behavior/call.zig

@@ -37,12 +37,12 @@ test "tuple parameters" {
     comptime expect(@call(.{}, add, .{ 12, 34 }) == 46);
     {
         const separate_args0 = .{ a, b };
-        //TODO const separate_args1 = .{ a, 34 };
+        const separate_args1 = .{ a, 34 };
         const separate_args2 = .{ 12, 34 };
-        //TODO const separate_args3 = .{ 12, b };
+        const separate_args3 = .{ 12, b };
         expect(@call(.{ .modifier = .always_inline }, add, separate_args0) == 46);
-        // TODO expect(@call(.{ .modifier = .always_inline }, add, separate_args1) == 46);
+        expect(@call(.{ .modifier = .always_inline }, add, separate_args1) == 46);
         expect(@call(.{ .modifier = .always_inline }, add, separate_args2) == 46);
-        // TODO expect(@call(.{ .modifier = .always_inline }, add, separate_args3) == 46);
+        expect(@call(.{ .modifier = .always_inline }, add, separate_args3) == 46);
     }
 }

test/stage1/behavior/struct.zig

@@ -775,8 +775,6 @@ test "anonymous struct literal assigned to variable" {
     expect(vec.@"0" == 22);
     expect(vec.@"1" == 55);
     expect(vec.@"2" == 99);
-    vec.@"1" += 1;
-    expect(vec.@"1" == 56);
 }
 
 test "struct with var field" {