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use super::{HandleMap, HandleSet, ModuleMap};
use crate::arena::{Arena, Handle};
pub struct ExpressionTracer<'tracer> {
pub constants: &'tracer Arena<crate::Constant>,
/// The arena in which we are currently tracing expressions.
pub expressions: &'tracer Arena<crate::Expression>,
/// The used map for `types`.
pub types_used: &'tracer mut HandleSet<crate::Type>,
/// The used map for `constants`.
pub constants_used: &'tracer mut HandleSet<crate::Constant>,
/// The used set for `arena`.
///
/// This points to whatever arena holds the expressions we are
/// currently tracing: either a function's expression arena, or
/// the module's constant expression arena.
pub expressions_used: &'tracer mut HandleSet<crate::Expression>,
/// The used set for the module's `global_expressions` arena.
///
/// If `None`, we are already tracing the constant expressions,
/// and `expressions_used` already refers to their handle set.
pub global_expressions_used: Option<&'tracer mut HandleSet<crate::Expression>>,
}
impl ExpressionTracer<'_> {
/// Propagate usage through `self.expressions`, starting with `self.expressions_used`.
///
/// Treat `self.expressions_used` as the initial set of "known
/// live" expressions, and follow through to identify all
/// transitively used expressions.
///
/// Mark types, constants, and constant expressions used directly
/// by `self.expressions` as used. Items used indirectly are not
/// marked.
///
/// [fe]: crate::Function::expressions
/// [ce]: crate::Module::global_expressions
pub fn trace_expressions(&mut self) {
log::trace!(
"entering trace_expression of {}",
if self.global_expressions_used.is_some() {
"function expressions"
} else {
"const expressions"
}
);
// We don't need recursion or a work list. Because an
// expression may only refer to other expressions that precede
// it in the arena, it suffices to make a single pass over the
// arena from back to front, marking the referents of used
// expressions as used themselves.
for (handle, expr) in self.expressions.iter().rev() {
// If this expression isn't used, it doesn't matter what it uses.
if !self.expressions_used.contains(handle) {
continue;
}
log::trace!("tracing new expression {:?}", expr);
use crate::Expression as Ex;
match *expr {
// Expressions that do not contain handles that need to be traced.
Ex::Literal(_)
| Ex::FunctionArgument(_)
| Ex::GlobalVariable(_)
| Ex::LocalVariable(_)
| Ex::CallResult(_)
| Ex::SubgroupBallotResult
| Ex::RayQueryProceedResult => {}
Ex::Constant(handle) => {
self.constants_used.insert(handle);
// Constants and expressions are mutually recursive, which
// complicates our nice one-pass algorithm. However, since
// constants don't refer to each other, we can get around
// this by looking *through* each constant and marking its
// initializer as used. Since `expr` refers to the constant,
// and the constant refers to the initializer, it must
// precede `expr` in the arena.
let init = self.constants[handle].init;
match self.global_expressions_used {
Some(ref mut used) => used.insert(init),
None => self.expressions_used.insert(init),
};
}
Ex::Override(_) => {
// All overrides are considered used by definition. We mark
// their types and initialization expressions as used in
// `compact::compact`, so we have no more work to do here.
}
Ex::ZeroValue(ty) => {
self.types_used.insert(ty);
}
Ex::Compose { ty, ref components } => {
self.types_used.insert(ty);
self.expressions_used
.insert_iter(components.iter().cloned());
}
Ex::Access { base, index } => self.expressions_used.insert_iter([base, index]),
Ex::AccessIndex { base, index: _ } => {
self.expressions_used.insert(base);
}
Ex::Splat { size: _, value } => {
self.expressions_used.insert(value);
}
Ex::Swizzle {
size: _,
vector,
pattern: _,
} => {
self.expressions_used.insert(vector);
}
Ex::Load { pointer } => {
self.expressions_used.insert(pointer);
}
Ex::ImageSample {
image,
sampler,
gather: _,
coordinate,
array_index,
offset,
ref level,
depth_ref,
} => {
self.expressions_used
.insert_iter([image, sampler, coordinate]);
self.expressions_used.insert_iter(array_index);
match self.global_expressions_used {
Some(ref mut used) => used.insert_iter(offset),
None => self.expressions_used.insert_iter(offset),
}
use crate::SampleLevel as Sl;
match *level {
Sl::Auto | Sl::Zero => {}
Sl::Exact(expr) | Sl::Bias(expr) => {
self.expressions_used.insert(expr);
}
Sl::Gradient { x, y } => self.expressions_used.insert_iter([x, y]),
}
self.expressions_used.insert_iter(depth_ref);
}
Ex::ImageLoad {
image,
coordinate,
array_index,
sample,
level,
} => {
self.expressions_used.insert(image);
self.expressions_used.insert(coordinate);
self.expressions_used.insert_iter(array_index);
self.expressions_used.insert_iter(sample);
self.expressions_used.insert_iter(level);
}
Ex::ImageQuery { image, ref query } => {
self.expressions_used.insert(image);
use crate::ImageQuery as Iq;
match *query {
Iq::Size { level } => self.expressions_used.insert_iter(level),
Iq::NumLevels | Iq::NumLayers | Iq::NumSamples => {}
}
}
Ex::Unary { op: _, expr } => {
self.expressions_used.insert(expr);
}
Ex::Binary { op: _, left, right } => {
self.expressions_used.insert_iter([left, right]);
}
Ex::Select {
condition,
accept,
reject,
} => self
.expressions_used
.insert_iter([condition, accept, reject]),
Ex::Derivative {
axis: _,
ctrl: _,
expr,
} => {
self.expressions_used.insert(expr);
}
Ex::Relational { fun: _, argument } => {
self.expressions_used.insert(argument);
}
Ex::Math {
fun: _,
arg,
arg1,
arg2,
arg3,
} => {
self.expressions_used.insert(arg);
self.expressions_used.insert_iter(arg1);
self.expressions_used.insert_iter(arg2);
self.expressions_used.insert_iter(arg3);
}
Ex::As {
expr,
kind: _,
convert: _,
} => {
self.expressions_used.insert(expr);
}
Ex::ArrayLength(expr) => {
self.expressions_used.insert(expr);
}
Ex::AtomicResult { ty, comparison: _ }
| Ex::WorkGroupUniformLoadResult { ty }
| Ex::SubgroupOperationResult { ty } => {
self.types_used.insert(ty);
}
Ex::RayQueryGetIntersection {
query,
committed: _,
} => {
self.expressions_used.insert(query);
}
}
}
}
}
impl ModuleMap {
/// Fix up all handles in `expr`.
///
/// Use the expression handle remappings in `operand_map`, and all
/// other mappings from `self`.
pub fn adjust_expression(
&self,
expr: &mut crate::Expression,
operand_map: &HandleMap<crate::Expression>,
) {
let adjust = |expr: &mut Handle<crate::Expression>| {
operand_map.adjust(expr);
};
use crate::Expression as Ex;
match *expr {
// Expressions that do not contain handles that need to be adjusted.
Ex::Literal(_)
| Ex::FunctionArgument(_)
| Ex::GlobalVariable(_)
| Ex::LocalVariable(_)
| Ex::CallResult(_)
| Ex::SubgroupBallotResult
| Ex::RayQueryProceedResult => {}
// All overrides are retained, so their handles never change.
Ex::Override(_) => {}
// Expressions that contain handles that need to be adjusted.
Ex::Constant(ref mut constant) => self.constants.adjust(constant),
Ex::ZeroValue(ref mut ty) => self.types.adjust(ty),
Ex::Compose {
ref mut ty,
ref mut components,
} => {
self.types.adjust(ty);
for component in components {
adjust(component);
}
}
Ex::Access {
ref mut base,
ref mut index,
} => {
adjust(base);
adjust(index);
}
Ex::AccessIndex {
ref mut base,
index: _,
} => adjust(base),
Ex::Splat {
size: _,
ref mut value,
} => adjust(value),
Ex::Swizzle {
size: _,
ref mut vector,
pattern: _,
} => adjust(vector),
Ex::Load { ref mut pointer } => adjust(pointer),
Ex::ImageSample {
ref mut image,
ref mut sampler,
gather: _,
ref mut coordinate,
ref mut array_index,
ref mut offset,
ref mut level,
ref mut depth_ref,
} => {
adjust(image);
adjust(sampler);
adjust(coordinate);
operand_map.adjust_option(array_index);
if let Some(ref mut offset) = *offset {
self.global_expressions.adjust(offset);
}
self.adjust_sample_level(level, operand_map);
operand_map.adjust_option(depth_ref);
}
Ex::ImageLoad {
ref mut image,
ref mut coordinate,
ref mut array_index,
ref mut sample,
ref mut level,
} => {
adjust(image);
adjust(coordinate);
operand_map.adjust_option(array_index);
operand_map.adjust_option(sample);
operand_map.adjust_option(level);
}
Ex::ImageQuery {
ref mut image,
ref mut query,
} => {
adjust(image);
self.adjust_image_query(query, operand_map);
}
Ex::Unary {
op: _,
ref mut expr,
} => adjust(expr),
Ex::Binary {
op: _,
ref mut left,
ref mut right,
} => {
adjust(left);
adjust(right);
}
Ex::Select {
ref mut condition,
ref mut accept,
ref mut reject,
} => {
adjust(condition);
adjust(accept);
adjust(reject);
}
Ex::Derivative {
axis: _,
ctrl: _,
ref mut expr,
} => adjust(expr),
Ex::Relational {
fun: _,
ref mut argument,
} => adjust(argument),
Ex::Math {
fun: _,
ref mut arg,
ref mut arg1,
ref mut arg2,
ref mut arg3,
} => {
adjust(arg);
operand_map.adjust_option(arg1);
operand_map.adjust_option(arg2);
operand_map.adjust_option(arg3);
}
Ex::As {
ref mut expr,
kind: _,
convert: _,
} => adjust(expr),
Ex::AtomicResult {
ref mut ty,
comparison: _,
} => self.types.adjust(ty),
Ex::WorkGroupUniformLoadResult { ref mut ty } => self.types.adjust(ty),
Ex::SubgroupOperationResult { ref mut ty } => self.types.adjust(ty),
Ex::ArrayLength(ref mut expr) => adjust(expr),
Ex::RayQueryGetIntersection {
ref mut query,
committed: _,
} => adjust(query),
}
}
fn adjust_sample_level(
&self,
level: &mut crate::SampleLevel,
operand_map: &HandleMap<crate::Expression>,
) {
let adjust = |expr: &mut Handle<crate::Expression>| operand_map.adjust(expr);
use crate::SampleLevel as Sl;
match *level {
Sl::Auto | Sl::Zero => {}
Sl::Exact(ref mut expr) => adjust(expr),
Sl::Bias(ref mut expr) => adjust(expr),
Sl::Gradient {
ref mut x,
ref mut y,
} => {
adjust(x);
adjust(y);
}
}
}
fn adjust_image_query(
&self,
query: &mut crate::ImageQuery,
operand_map: &HandleMap<crate::Expression>,
) {
use crate::ImageQuery as Iq;
match *query {
Iq::Size { ref mut level } => operand_map.adjust_option(level),
Iq::NumLevels | Iq::NumLayers | Iq::NumSamples => {}
}
}
}