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Customize Function and BasicBlock to carry both a SPIR-V ID and an index, for O(1) access. #341

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Customize Function and BasicBlock to carry both a SPIR-V ID and an index, for O(1) access. #341

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006718d
builder: rely on `&mut self` (instead of `&self`) on most methods.
eddyb Jul 20, 2025
f8f5301
Customize `Function` and `BasicBlock` to carry both a SPIR-V ID and a…
eddyb Jul 20, 2025
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107 changes: 46 additions & 61 deletions crates/rustc_codegen_spirv/src/builder/builder_methods.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,9 @@ use crate::maybe_pqp_cg_ssa as rustc_codegen_ssa;

use super::Builder;
use crate::abi::ConvSpirvType;
use crate::builder_spirv::{BuilderCursor, SpirvConst, SpirvValue, SpirvValueExt, SpirvValueKind};
use crate::builder_spirv::{
SpirvBlockCursor, SpirvConst, SpirvValue, SpirvValueExt, SpirvValueKind,
};
use crate::codegen_cx::CodegenCx;
use crate::custom_insts::{CustomInst, CustomOp};
use crate::spirv_type::SpirvType;
Expand Down Expand Up @@ -127,7 +129,7 @@ fn memset_fill_u64(b: u8) -> u64 {
}

fn memset_dynamic_scalar(
builder: &Builder<'_, '_>,
builder: &mut Builder<'_, '_>,
fill_var: Word,
byte_width: usize,
is_float: bool,
Expand All @@ -154,7 +156,7 @@ fn memset_dynamic_scalar(

impl<'a, 'tcx> Builder<'a, 'tcx> {
#[instrument(level = "trace", skip(self))]
fn ordering_to_semantics_def(&self, ordering: AtomicOrdering) -> SpirvValue {
fn ordering_to_semantics_def(&mut self, ordering: AtomicOrdering) -> SpirvValue {
let mut invalid_seq_cst = false;
let semantics = match ordering {
AtomicOrdering::Relaxed => MemorySemantics::NONE,
Expand All @@ -166,8 +168,8 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
| MemorySemantics::ACQUIRE_RELEASE
}
AtomicOrdering::SeqCst => {
let emit = self.emit();
let memory_model = emit.module_ref().memory_model.as_ref().unwrap();
let builder = self.emit();
let memory_model = builder.module_ref().memory_model.as_ref().unwrap();
if memory_model.operands[1].unwrap_memory_model() == MemoryModel::Vulkan {
invalid_seq_cst = true;
}
Expand Down Expand Up @@ -263,7 +265,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
}

#[instrument(level = "trace", skip(self))]
fn memset_dynamic_pattern(&self, ty: &SpirvType<'tcx>, fill_var: Word) -> Word {
fn memset_dynamic_pattern(&mut self, ty: &SpirvType<'tcx>, fill_var: Word) -> Word {
match *ty {
SpirvType::Void => self.fatal("memset invalid on void pattern"),
SpirvType::Bool => self.fatal("memset invalid on bool pattern"),
Expand Down Expand Up @@ -750,9 +752,9 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
let ptr_id = ptr.def(self);

let maybe_original_access_chain = {
let emit = self.emit();
let module = emit.module_ref();
let current_func_blocks = emit
let builder = self.emit();
let module = builder.module_ref();
let current_func_blocks = builder
.selected_function()
.and_then(|func_idx| Some(&module.functions.get(func_idx)?.blocks[..]))
.unwrap_or_default();
Expand Down Expand Up @@ -823,28 +825,28 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
)
)]
fn emit_access_chain(
&self,
&mut self,
result_type: <Self as BackendTypes>::Type,
pointer: Word,
ptr_base_index: Option<SpirvValue>,
indices: Vec<Word>,
is_inbounds: bool,
) -> SpirvValue {
let mut emit = self.emit();
let mut builder = self.emit();

let non_zero_ptr_base_index =
ptr_base_index.filter(|&idx| self.builder.lookup_const_scalar(idx) != Some(0));
if let Some(ptr_base_index) = non_zero_ptr_base_index {
let result = if is_inbounds {
emit.in_bounds_ptr_access_chain(
builder.in_bounds_ptr_access_chain(
result_type,
None,
pointer,
ptr_base_index.def(self),
indices,
)
} else {
emit.ptr_access_chain(
builder.ptr_access_chain(
result_type,
None,
pointer,
Expand All @@ -857,9 +859,9 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
result
} else {
if is_inbounds {
emit.in_bounds_access_chain(result_type, None, pointer, indices)
builder.in_bounds_access_chain(result_type, None, pointer, indices)
} else {
emit.access_chain(result_type, None, pointer, indices)
builder.access_chain(result_type, None, pointer, indices)
}
.unwrap()
}
Expand Down Expand Up @@ -1091,21 +1093,9 @@ impl<'a, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'tcx> {

#[instrument(level = "trace", skip(cx))]
fn build(cx: &'a Self::CodegenCx, llbb: Self::BasicBlock) -> Self {
let cursor = cx.builder.select_block_by_id(llbb);
// FIXME(eddyb) change `Self::Function` to be more like a function index.
let current_fn = {
let emit = cx.emit_with_cursor(cursor);
let selected_function = emit.selected_function().unwrap();
let selected_function = &emit.module_ref().functions[selected_function];
let def_inst = selected_function.def.as_ref().unwrap();
let def = def_inst.result_id.unwrap();
let ty = def_inst.operands[1].unwrap_id_ref();
def.with_type(ty)
};
Self {
cx,
cursor,
current_fn,
current_block: llbb,
current_span: Default::default(),
}
}
Expand Down Expand Up @@ -1201,17 +1191,18 @@ impl<'a, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'tcx> {
llfn: Self::Function,
_name: &str,
) -> Self::BasicBlock {
let cursor_fn = cx.builder.select_function_by_id(llfn.def_cx(cx));
cx.emit_with_cursor(cursor_fn).begin_block(None).unwrap()
let mut builder = cx.builder.builder_for_fn(llfn);
let id = builder.begin_block(None).unwrap();
let index_in_builder = builder.selected_block().unwrap();
SpirvBlockCursor {
parent_fn: llfn,
id,
index_in_builder,
}
}

fn append_sibling_block(&mut self, _name: &str) -> Self::BasicBlock {
self.emit_with_cursor(BuilderCursor {
function: self.cursor.function,
block: None,
})
.begin_block(None)
.unwrap()
fn append_sibling_block(&mut self, name: &str) -> Self::BasicBlock {
Self::append_block(self.cx, self.current_block.parent_fn, name)
}

fn switch_to_block(&mut self, llbb: Self::BasicBlock) {
Expand Down Expand Up @@ -1239,7 +1230,7 @@ impl<'a, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'tcx> {
}

fn br(&mut self, dest: Self::BasicBlock) {
self.emit().branch(dest).unwrap();
self.emit().branch(dest.id).unwrap();
}

fn cond_br(
Expand All @@ -1257,7 +1248,7 @@ impl<'a, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'tcx> {
Some(SpirvConst::Scalar(0)) => self.br(else_llbb),
_ => {
self.emit()
.branch_conditional(cond, then_llbb, else_llbb, empty())
.branch_conditional(cond, then_llbb.id, else_llbb.id, empty())
.unwrap();
}
}
Expand Down Expand Up @@ -1330,9 +1321,11 @@ impl<'a, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'tcx> {
)),
};
let cases = cases
.map(|(i, b)| (construct_case(self, signed, i), b))
.map(|(i, b)| (construct_case(self, signed, i), b.id))
.collect::<Vec<_>>();
self.emit().switch(v.def(self), else_llbb, cases).unwrap();
self.emit()
.switch(v.def(self), else_llbb.id, cases)
.unwrap();
}

fn invoke(
Expand All @@ -1349,7 +1342,7 @@ impl<'a, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'tcx> {
) -> Self::Value {
// Exceptions don't exist, jump directly to then block
let result = self.call(llty, fn_attrs, fn_abi, llfn, args, funclet, instance);
self.emit().branch(then).unwrap();
self.emit().branch(then.id).unwrap();
result
}

Expand Down Expand Up @@ -2741,16 +2734,16 @@ impl<'a, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'tcx> {
.with_type(agg_val.ty)
}

fn set_personality_fn(&mut self, _personality: Self::Value) {
fn set_personality_fn(&mut self, _personality: Self::Function) {
todo!()
}

// These are used by everyone except msvc
fn cleanup_landing_pad(&mut self, _pers_fn: Self::Value) -> (Self::Value, Self::Value) {
fn cleanup_landing_pad(&mut self, _pers_fn: Self::Function) -> (Self::Value, Self::Value) {
todo!()
}

fn filter_landing_pad(&mut self, _pers_fn: Self::Value) -> (Self::Value, Self::Value) {
fn filter_landing_pad(&mut self, _pers_fn: Self::Function) -> (Self::Value, Self::Value) {
todo!()
}

Expand Down Expand Up @@ -2979,16 +2972,6 @@ impl<'a, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'tcx> {
// be fixed upstream, so we never see any "function pointer" values being
// created just to perform direct calls.
let (callee_val, result_type, argument_types) = match self.lookup_type(callee.ty) {
// HACK(eddyb) this seems to be needed, but it's not what `get_fn_addr`
// produces, are these coming from inside `rustc_codegen_spirv`?
SpirvType::Function {
return_type,
arguments,
} => {
assert_ty_eq!(self, callee_ty, callee.ty);
(callee.def(self), return_type, arguments)
}

Comment on lines 2974 to -2991
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@eddyb eddyb Jul 20, 2025 •
edited
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This special-case could be removed because it could only be reached by the custom entry-point logic passing a function as the callee, while rustc_codegen_ssa always expects a function pointer (this matches up with the entry_func -> self.get_fn_addr(entry_instance) change in entry.rs).

While direct calls should IMO be supported as first-class, that would require call to be able to take Self::Function as the callee, not Self::Value, as the only rustc_codegen_ssa interface to get a Self::Value for a function is get_fn_addr (which always creates a pointer).

(This also makes sense if you consider that Self::Value is really meant to be an IR value, ideally something vaguely-register-like, that can partake in runtime dataflow, and "a function" doesn't fit that without being referred to indirectly, i.e. as a function pointer)

SpirvType::Pointer { pointee } => match self.lookup_type(pointee) {
SpirvType::Function {
return_type,
Expand All @@ -3014,7 +2997,7 @@ impl<'a, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'tcx> {
},

_ => bug!(
"call expected function or `fn` pointer type, got `{}`",
"call expected `fn` pointer type, got `{}`",
self.debug_type(callee.ty)
),
};
Expand Down Expand Up @@ -3091,18 +3074,20 @@ impl<'a, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'tcx> {
struct FormatArgsNotRecognized(String);

// HACK(eddyb) this is basically a `try` block.
let try_decode_and_remove_format_args = || {
let mut try_decode_and_remove_format_args = || {
let mut decoded_format_args = DecodedFormatArgs::default();

let const_u32_as_usize = |ct_id| match self.builder.lookup_const_by_id(ct_id)? {
// HACK(eddyb) work around mutable borrowing conflicts.
let cx = self.cx;

let const_u32_as_usize = |ct_id| match cx.builder.lookup_const_by_id(ct_id)? {
SpirvConst::Scalar(x) => Some(u32::try_from(x).ok()? as usize),
_ => None,
};
let const_slice_as_elem_ids = |ptr_id: Word, len: usize| {
if let SpirvConst::PtrTo { pointee } =
self.builder.lookup_const_by_id(ptr_id)?
if let SpirvConst::PtrTo { pointee } = cx.builder.lookup_const_by_id(ptr_id)?
&& let SpirvConst::Composite(elems) =
self.builder.lookup_const_by_id(pointee)?
cx.builder.lookup_const_by_id(pointee)?
&& elems.len() == len
{
return Some(elems);
Expand Down
9 changes: 7 additions & 2 deletions crates/rustc_codegen_spirv/src/builder/ext_inst.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -41,7 +41,7 @@ impl ExtInst {

impl<'a, 'tcx> Builder<'a, 'tcx> {
pub fn custom_inst(
&self,
&mut self,
result_type: Word,
inst: custom_insts::CustomInst<Operand>,
) -> SpirvValue {
Expand All @@ -58,7 +58,12 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
.with_type(result_type)
}

pub fn gl_op(&self, op: GLOp, result_type: Word, args: impl AsRef<[SpirvValue]>) -> SpirvValue {
pub fn gl_op(
&mut self,
op: GLOp,
result_type: Word,
args: impl AsRef<[SpirvValue]>,
) -> SpirvValue {
let args = args.as_ref();
let glsl = self.ext_inst.borrow_mut().import_glsl(self);
self.emit()
Expand Down
34 changes: 17 additions & 17 deletions crates/rustc_codegen_spirv/src/builder/intrinsics.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -381,7 +381,7 @@ impl<'a, 'tcx> IntrinsicCallBuilderMethods<'tcx> for Builder<'a, 'tcx> {
}

impl Builder<'_, '_> {
pub fn count_ones(&self, arg: SpirvValue) -> SpirvValue {
pub fn count_ones(&mut self, arg: SpirvValue) -> SpirvValue {
let ty = arg.ty;
match self.cx.lookup_type(ty) {
SpirvType::Integer(bits, false) => {
Expand Down Expand Up @@ -426,7 +426,7 @@ impl Builder<'_, '_> {
}
}

pub fn bit_reverse(&self, arg: SpirvValue) -> SpirvValue {
pub fn bit_reverse(&mut self, arg: SpirvValue) -> SpirvValue {
let ty = arg.ty;
match self.cx.lookup_type(ty) {
SpirvType::Integer(bits, false) => {
Expand Down Expand Up @@ -489,7 +489,7 @@ impl Builder<'_, '_> {
}

pub fn count_leading_trailing_zeros(
&self,
&mut self,
arg: SpirvValue,
trailing: bool,
non_zero: bool,
Expand All @@ -501,9 +501,9 @@ impl Builder<'_, '_> {
let u32 = SpirvType::Integer(32, false).def(self.span(), self);

let glsl = self.ext_inst.borrow_mut().import_glsl(self);
let find_xsb = |arg, offset: i32| {
let find_xsb = |this: &mut Self, arg, offset: i32| {
if trailing {
let lsb = self
let lsb = this
.emit()
.ext_inst(
u32,
Expand All @@ -516,12 +516,12 @@ impl Builder<'_, '_> {
if offset == 0 {
lsb
} else {
let const_offset = self.constant_i32(self.span(), offset).def(self);
self.emit().i_add(u32, None, const_offset, lsb).unwrap()
let const_offset = this.constant_i32(this.span(), offset).def(this);
this.emit().i_add(u32, None, const_offset, lsb).unwrap()
}
} else {
// rust is always unsigned, so FindUMsb
let msb_bit = self
let msb_bit = this
.emit()
.ext_inst(
u32,
Expand All @@ -533,21 +533,21 @@ impl Builder<'_, '_> {
.unwrap();
// the glsl op returns the Msb bit, not the amount of leading zeros of this u32
// leading zeros = 31 - Msb bit
let const_offset = self.constant_i32(self.span(), 31 - offset).def(self);
self.emit().i_sub(u32, None, const_offset, msb_bit).unwrap()
let const_offset = this.constant_i32(this.span(), 31 - offset).def(this);
this.emit().i_sub(u32, None, const_offset, msb_bit).unwrap()
}
};

let converted = match bits {
8 | 16 => {
let arg = self.emit().u_convert(u32, None, arg.def(self)).unwrap();
if trailing {
find_xsb(arg, 0)
find_xsb(self, arg, 0)
} else {
find_xsb(arg, bits as i32 - 32)
find_xsb(self, arg, bits as i32 - 32)
}
}
32 => find_xsb(arg.def(self), 0),
32 => find_xsb(self, arg.def(self), 0),
64 => {
let u32_0 = self.constant_int(u32, 0).def(self);
let u32_32 = self.constant_u32(self.span(), 32).def(self);
Expand All @@ -562,16 +562,16 @@ impl Builder<'_, '_> {

if trailing {
let use_lower = self.emit().i_equal(bool, None, lower, u32_0).unwrap();
let lower_bits = find_xsb(lower, 32);
let higher_bits = find_xsb(higher, 0);
let lower_bits = find_xsb(self, lower, 32);
let higher_bits = find_xsb(self, higher, 0);
self.emit()
.select(u32, None, use_lower, higher_bits, lower_bits)
.unwrap()
} else {
let use_higher =
self.emit().i_equal(bool, None, higher, u32_0).unwrap();
let lower_bits = find_xsb(lower, 0);
let higher_bits = find_xsb(higher, 32);
let lower_bits = find_xsb(self, lower, 0);
let higher_bits = find_xsb(self, higher, 32);
self.emit()
.select(u32, None, use_higher, lower_bits, higher_bits)
.unwrap()
Expand Down
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