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agila_open_tool/tools/v/vlib/v2_toberemoved/abi/abi.v
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// Copyright (c) 2026 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
module abi
import v2.mir
import v2.pref
pub enum X64Abi {
sysv
windows
}
const sysv_int_arg_reg_count = 6
const sysv_sse_arg_reg_count = 8
const sysv_max_direct_aggregate_size = 16
struct SysVLocationState {
mut:
int_regs int
sse_regs int
stack_slots int
}
// lower annotates MIR with ABI classification metadata.
// Current scope is intentionally conservative: it classifies which arguments
// and return values must be passed indirectly for each function.
pub fn lower(mut m mir.Module, arch pref.Arch) {
lower_with_x64_abi(mut m, arch, .sysv)
}
pub fn lower_with_x64_abi(mut m mir.Module, arch pref.Arch, x64_abi X64Abi) {
is_x64 := arch == .x64
mut fn_by_name := map[string]int{}
for i := 0; i < m.funcs.len; i++ {
mut f := &m.funcs[i]
fn_by_name[f.name] = i
if is_x64 {
f.abi_ret_class = abi_value_class(m, f.typ, arch, x64_abi)
f.abi_ret_indirect = abi_class_is_indirect(f.abi_ret_class, m, f.typ, arch, x64_abi)
} else {
f.abi_ret_indirect = needs_indirect(m, f.typ, arch, x64_abi)
}
f.abi_param_class = []mir.AbiArgClass{len: f.params.len, init: .in_reg}
if is_x64 {
f.abi_param_classes = []mir.AbiValueClass{len: f.params.len}
f.abi_param_layouts = []mir.AbiValueLayout{len: f.params.len}
}
mut param_loc_state := SysVLocationState{}
if arch == .x64 && x64_abi == .sysv && f.abi_ret_indirect {
param_loc_state.int_regs = 1
}
for pi, param_id in f.params {
if param_id < 0 || param_id >= m.values.len {
continue
}
param_typ := m.values[param_id].typ
if is_x64 {
param_class := abi_value_class(m, param_typ, arch, x64_abi)
f.abi_param_classes[pi] = param_class
if x64_abi == .sysv {
f.abi_param_layouts[pi] = sysv_assign_value_layout(param_class, mut
param_loc_state)
}
if abi_class_is_indirect(param_class, m, param_typ, arch, x64_abi) {
f.abi_param_class[pi] = .indirect
}
} else if needs_indirect(m, param_typ, arch, x64_abi) {
f.abi_param_class[pi] = .indirect
}
}
}
lower_calls(mut m, arch, x64_abi, fn_by_name)
}
fn needs_indirect(m mir.Module, typ_id int, arch pref.Arch, x64_abi X64Abi) bool {
ssa_mod := m.ssa()
if ssa_mod == unsafe { nil } || typ_id <= 0 || typ_id >= ssa_mod.type_store.types.len {
return false
}
typ := ssa_mod.type_store.types[typ_id]
if typ.kind !in [.struct_t, .array_t] {
return false
}
size := m.type_size(typ_id)
return match arch {
.arm64 {
size > 16
}
.x64 {
match x64_abi {
.sysv { size > sysv_max_direct_aggregate_size }
.windows { size !in [1, 2, 4, 8] }
}
}
else {
size > 16
}
}
}
fn abi_class_is_indirect(value_class mir.AbiValueClass, m mir.Module, typ_id int, arch pref.Arch, x64_abi X64Abi) bool {
if value_class.mode == .indirect {
return true
}
return needs_indirect(m, typ_id, arch, x64_abi)
}
fn abi_value_class(m mir.Module, typ_id int, arch pref.Arch, x64_abi X64Abi) mir.AbiValueClass {
ssa_mod := m.ssa()
size := m.type_size(typ_id)
if ssa_mod == unsafe { nil } || typ_id <= 0 || typ_id >= ssa_mod.type_store.types.len {
return mir.AbiValueClass{
mode: .direct
size: size
}
}
typ := ssa_mod.type_store.types[typ_id]
if arch == .x64 && x64_abi == .sysv {
if typ.kind !in [.struct_t, .array_t] {
return sysv_scalar_abi_value_class(m, typ_id)
}
return sysv_abi_value_class(m, typ_id)
}
indirect := needs_indirect(m, typ_id, arch, x64_abi)
return mir.AbiValueClass{
mode: if indirect { .indirect } else { .direct }
size: size
}
}
fn sysv_scalar_abi_value_class(m mir.Module, typ_id int) mir.AbiValueClass {
ssa_mod := m.ssa()
size := m.type_size(typ_id)
if ssa_mod == unsafe { nil } || typ_id <= 0 || typ_id >= ssa_mod.type_store.types.len {
return mir.AbiValueClass{
mode: .direct
size: size
}
}
typ := ssa_mod.type_store.types[typ_id]
classes := match typ.kind {
.int_t, .ptr_t, .func_t {
[mir.AbiEightbyteClass.integer]
}
.float_t {
match typ.width {
32, 64 { [mir.AbiEightbyteClass.sse] }
128 { [mir.AbiEightbyteClass.sse, .sseup] }
else { []mir.AbiEightbyteClass{} }
}
}
else {
[]mir.AbiEightbyteClass{}
}
}
return mir.AbiValueClass{
mode: .direct
size: size
classes: classes
}
}
fn sysv_abi_value_class(m mir.Module, typ_id int) mir.AbiValueClass {
size := m.type_size(typ_id)
if size <= 0 {
return mir.AbiValueClass{
mode: .direct
size: size
}
}
if sysv_aggregate_must_be_memory_before_classification(size) {
return sysv_memory_value_class(size)
}
mut classes := []mir.AbiEightbyteClass{len: (size + 7) / 8, init: .no_class}
mut visiting := map[int]bool{}
if !sysv_classify_type_into(m, typ_id, 0, mut classes, mut visiting) {
return sysv_memory_value_class(size)
}
classes = sysv_post_merge_classes(size, classes)
if classes.len == 1 && classes[0] == .memory {
return sysv_memory_value_class(size)
}
return mir.AbiValueClass{
mode: .direct
size: size
classes: classes
}
}
fn sysv_aggregate_must_be_memory_before_classification(size int) bool {
// Current SSA aggregate types do not model a SysV vector aggregate larger
// than two eightbytes, so larger struct/array aggregates cannot be passed
// in registers and should not be classified element by element.
return size > sysv_max_direct_aggregate_size
}
fn sysv_memory_value_class(size int) mir.AbiValueClass {
return mir.AbiValueClass{
mode: .indirect
size: size
classes: [.memory]
}
}
fn sysv_classify_type_into(m mir.Module, typ_id int, byte_offset int, mut classes []mir.AbiEightbyteClass, mut visiting map[int]bool) bool {
ssa_mod := m.ssa()
if ssa_mod == unsafe { nil } || typ_id <= 0 || typ_id >= ssa_mod.type_store.types.len {
return true
}
if visiting[typ_id] {
return sysv_merge_class_range(mut classes, byte_offset, 8, .integer)
}
visiting[typ_id] = true
typ := ssa_mod.type_store.types[typ_id]
ok := match typ.kind {
.int_t, .ptr_t, .func_t {
sysv_merge_class_range(mut classes, byte_offset, m.type_size(typ_id), .integer)
}
.float_t {
match typ.width {
32, 64 {
sysv_merge_class_range(mut classes, byte_offset, m.type_size(typ_id), .sse)
}
80 {
false
}
128 {
sysv_merge_class_range(mut classes, byte_offset, 8, .sse)
&& sysv_merge_class_range(mut classes, byte_offset + 8, 8, .sseup)
}
else {
false
}
}
}
.array_t {
sysv_classify_array_into(m, typ.elem_type, typ.len, byte_offset, mut classes, mut
visiting)
}
.struct_t {
sysv_classify_struct_into(m, typ.fields, byte_offset, mut classes, mut visiting)
}
.void_t, .label_t, .metadata_t {
true
}
}
visiting.delete(typ_id)
return ok
}
fn sysv_classify_array_into(m mir.Module, elem_type int, len int, byte_offset int, mut classes []mir.AbiEightbyteClass, mut visiting map[int]bool) bool {
elem_size := m.type_size(elem_type)
for i := 0; i < len; i++ {
if !sysv_classify_type_into(m, elem_type, byte_offset + i * elem_size, mut classes, mut
visiting) {
return false
}
}
return true
}
fn sysv_classify_struct_into(m mir.Module, fields []int, byte_offset int, mut classes []mir.AbiEightbyteClass, mut visiting map[int]bool) bool {
mut field_offset := 0
for field_typ in fields {
align := m.type_align(field_typ)
if align > 1 && field_offset % align != 0 {
field_offset = (field_offset + align - 1) & ~(align - 1)
}
if !sysv_classify_type_into(m, field_typ, byte_offset + field_offset, mut classes, mut
visiting) {
return false
}
field_offset += m.type_size(field_typ)
}
return true
}
fn sysv_merge_class_range(mut classes []mir.AbiEightbyteClass, byte_offset int, size int, class mir.AbiEightbyteClass) bool {
if size <= 0 {
return true
}
start := byte_offset / 8
end := (byte_offset + size + 7) / 8
if start < 0 || end > classes.len {
return false
}
for i := start; i < end; i++ {
classes[i] = sysv_merge_eightbyte_class(classes[i], class)
if classes[i] == .memory {
return false
}
}
return true
}
fn sysv_merge_eightbyte_class(a mir.AbiEightbyteClass, b mir.AbiEightbyteClass) mir.AbiEightbyteClass {
if a == b {
return a
}
if a == .no_class {
return b
}
if b == .no_class {
return a
}
if a == .memory || b == .memory {
return .memory
}
if a == .integer || b == .integer {
return .integer
}
return .sse
}
fn sysv_post_merge_classes(size int, input []mir.AbiEightbyteClass) []mir.AbiEightbyteClass {
mut classes := input.clone()
for class in classes {
if class == .memory {
return [.memory]
}
}
if size > sysv_max_direct_aggregate_size {
mut vector_like := classes.len > 0 && classes[0] == .sse
for i := 1; i < classes.len; i++ {
if classes[i] != .sseup {
vector_like = false
break
}
}
if !vector_like {
return [.memory]
}
}
for i, class in classes {
if class == .sseup && (i == 0 || classes[i - 1] !in [.sse, .sseup]) {
classes[i] = .sse
}
}
return classes
}
fn sysv_assign_value_layout(value_class mir.AbiValueClass, mut state SysVLocationState) mir.AbiValueLayout {
if value_class.classes.len == 0 {
return mir.AbiValueLayout{
value_class: value_class
}
}
if value_class.mode == .indirect || value_class.classes == [mir.AbiEightbyteClass.memory] {
return sysv_indirect_pointer_layout(value_class, mut state)
}
mut needed_int := 0
mut needed_sse := 0
for class in value_class.classes {
match class {
.integer { needed_int++ }
.sse { needed_sse++ }
else {}
}
}
if state.int_regs + needed_int > sysv_int_arg_reg_count
|| state.sse_regs + needed_sse > sysv_sse_arg_reg_count {
return sysv_stack_value_layout(value_class, mut state)
}
mut locs := []mir.AbiLocation{cap: value_class.classes.len}
mut last_sse := -1
for i, class in value_class.classes {
offset := i * 8
match class {
.integer {
locs << mir.AbiLocation{
kind: .int_reg
index: state.int_regs
offset: offset
class: class
}
state.int_regs++
}
.sse {
last_sse = state.sse_regs
locs << mir.AbiLocation{
kind: .sse_reg
index: state.sse_regs
offset: offset
class: class
}
state.sse_regs++
}
.sseup {
locs << mir.AbiLocation{
kind: .sse_reg
index: if last_sse >= 0 { last_sse } else { state.sse_regs }
offset: offset
class: class
}
}
else {
locs << mir.AbiLocation{
kind: .none
index: -1
offset: offset
class: class
}
}
}
}
return mir.AbiValueLayout{
value_class: value_class
locs: locs
}
}
fn sysv_indirect_pointer_layout(value_class mir.AbiValueClass, mut state SysVLocationState) mir.AbiValueLayout {
mut locs := []mir.AbiLocation{cap: 1}
if state.int_regs < sysv_int_arg_reg_count {
locs << mir.AbiLocation{
kind: .int_reg
index: state.int_regs
offset: 0
class: .integer
}
state.int_regs++
} else {
locs << mir.AbiLocation{
kind: .stack
index: state.stack_slots
offset: 0
class: .integer
}
state.stack_slots++
}
return mir.AbiValueLayout{
value_class: value_class
locs: locs
}
}
fn sysv_stack_value_layout(value_class mir.AbiValueClass, mut state SysVLocationState) mir.AbiValueLayout {
slots := if value_class.size > 0 { (value_class.size + 7) / 8 } else { value_class.classes.len }
mut locs := []mir.AbiLocation{cap: slots}
for i := 0; i < slots; i++ {
class := if i < value_class.classes.len {
value_class.classes[i]
} else {
mir.AbiEightbyteClass.memory
}
locs << mir.AbiLocation{
kind: .stack
index: state.stack_slots
offset: i * 8
class: class
}
state.stack_slots++
}
return mir.AbiValueLayout{
value_class: value_class
locs: locs
}
}
fn fallback_arg_type(m mir.Module, arg_id int) int {
if arg_id < 0 || arg_id >= m.values.len {
return 0
}
if logical_typ := logical_arg_type_from_value(m, arg_id, 0) {
return logical_typ
}
return m.values[arg_id].typ
}
fn logical_arg_type_from_value(m mir.Module, val_id int, depth int) ?int {
if depth > 8 || val_id < 0 || val_id >= m.values.len {
return none
}
val := m.values[val_id]
if val.kind != .instruction {
return none
}
instr := m.instrs[val.index]
match instr.op {
.alloca {
if val.typ <= 0 || val.typ >= m.type_store.types.len {
return none
}
typ := m.type_store.types[val.typ]
if typ.kind != .ptr_t || typ.elem_type <= 0 || typ.elem_type >= m.type_store.types.len {
return none
}
elem_typ := m.type_store.types[typ.elem_type]
if elem_typ.kind in [.struct_t, .array_t] {
return typ.elem_type
}
}
.bitcast {
if instr.operands.len > 0 {
return logical_arg_type_from_value(m, instr.operands[0], depth + 1)
}
}
.assign {
if instr.operands.len > 1 {
return logical_arg_type_from_value(m, instr.operands[1], depth + 1)
}
}
else {}
}
return none
}
fn lower_calls(mut m mir.Module, arch pref.Arch, x64_abi X64Abi, fn_by_name map[string]int) {
if arch !in [.arm64, .x64] {
return
}
is_x64 := arch == .x64
for i := 0; i < m.instrs.len; i++ {
mut instr := &m.instrs[i]
if instr.op !in [.call, .call_indirect, .call_sret] || instr.operands.len == 0 {
continue
}
ret_typ, sig_param_types := call_signature(m, instr, fn_by_name)
ret_class := if is_x64 {
abi_value_class(m, ret_typ, arch, x64_abi)
} else {
mir.AbiValueClass{}
}
ret_indirect := if is_x64 {
abi_class_is_indirect(ret_class, m, ret_typ, arch, x64_abi)
} else {
needs_indirect(m, ret_typ, arch, x64_abi)
}
num_args := instr.operands.len - 1
instr.abi_arg_class = []mir.AbiArgClass{len: num_args, init: .in_reg}
if is_x64 {
instr.abi_arg_classes = []mir.AbiValueClass{len: num_args}
instr.abi_arg_layouts = []mir.AbiValueLayout{len: num_args}
}
mut arg_loc_state := SysVLocationState{}
if arch == .x64 && x64_abi == .sysv && ret_indirect {
arg_loc_state.int_regs = 1
}
for arg_idx := 0; arg_idx < num_args; arg_idx++ {
mut arg_typ := 0
if arg_idx < sig_param_types.len && sig_param_types[arg_idx] > 0 {
arg_typ = sig_param_types[arg_idx]
} else {
arg_id := instr.operands[arg_idx + 1]
arg_typ = fallback_arg_type(m, arg_id)
}
if is_x64 {
arg_class := abi_value_class(m, arg_typ, arch, x64_abi)
instr.abi_arg_classes[arg_idx] = arg_class
if x64_abi == .sysv {
instr.abi_arg_layouts[arg_idx] = sysv_assign_value_layout(arg_class, mut
arg_loc_state)
}
if abi_class_is_indirect(arg_class, m, arg_typ, arch, x64_abi) {
instr.abi_arg_class[arg_idx] = .indirect
}
} else if needs_indirect(m, arg_typ, arch, x64_abi) {
instr.abi_arg_class[arg_idx] = .indirect
}
}
instr.abi_ret_class = ret_class
instr.abi_ret_indirect = ret_indirect
// Lower ABI-indirect returns to call_sret for backend consumption.
if instr.abi_ret_indirect {
instr.op = .call_sret
}
}
}
fn call_signature(m mir.Module, instr &mir.Instruction, fn_by_name map[string]int) (int, []int) {
mut ret_typ := instr.typ
mut param_types := []int{}
if instr.operands.len == 0 {
return ret_typ, param_types
}
if instr.op in [.call, .call_sret] {
callee_id := instr.operands[0]
if callee_id >= 0 && callee_id < m.values.len {
callee_name := m.values[callee_id].name
if callee_name != '' && callee_name in fn_by_name {
fn_idx := fn_by_name[callee_name]
if fn_idx >= 0 && fn_idx < m.funcs.len {
callee := m.funcs[fn_idx]
ret_typ = callee.typ
param_types = []int{len: callee.params.len}
for i, pid in callee.params {
if pid >= 0 && pid < m.values.len {
param_types[i] = m.values[pid].typ
}
}
}
}
}
} else if instr.op == .call_indirect {
callee_id := instr.operands[0]
if callee_id >= 0 && callee_id < m.values.len {
fn_ptr_typ_id := m.values[callee_id].typ
if fn_ptr_typ_id > 0 && fn_ptr_typ_id < m.type_store.types.len {
fn_ptr_typ := m.type_store.types[fn_ptr_typ_id]
if fn_ptr_typ.kind == .ptr_t && fn_ptr_typ.elem_type > 0
&& fn_ptr_typ.elem_type < m.type_store.types.len {
fn_typ := m.type_store.types[fn_ptr_typ.elem_type]
if fn_typ.kind == .func_t {
ret_typ = fn_typ.ret_type
param_types = fn_typ.params.clone()
}
} else if fn_ptr_typ.kind == .func_t {
// Function pointer extracted from struct field via extractvalue
// has func_t type directly (not wrapped in ptr_t).
ret_typ = fn_ptr_typ.ret_type
param_types = fn_ptr_typ.params.clone()
}
}
}
}
// Fallback to call operand types when we could not resolve a signature.
if param_types.len == 0 {
num_args := if instr.operands.len > 0 { instr.operands.len - 1 } else { 0 }
param_types = []int{len: num_args}
for i := 0; i < num_args; i++ {
arg_id := instr.operands[i + 1]
param_types[i] = fallback_arg_type(m, arg_id)
}
}
return ret_typ, param_types
}