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// Copyright 2021 The Tint Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "src/transform/decompose_memory_access.h"
#include <memory>
#include <string>
#include <unordered_map>
#include <utility>
#include <vector>
#include "src/ast/assignment_statement.h"
#include "src/ast/call_statement.h"
#include "src/ast/disable_validation_decoration.h"
#include "src/ast/type_name.h"
#include "src/ast/unary_op.h"
#include "src/block_allocator.h"
#include "src/program_builder.h"
#include "src/sem/array.h"
#include "src/sem/atomic_type.h"
#include "src/sem/call.h"
#include "src/sem/member_accessor_expression.h"
#include "src/sem/reference_type.h"
#include "src/sem/statement.h"
#include "src/sem/struct.h"
#include "src/sem/variable.h"
#include "src/utils/hash.h"
#include "src/utils/map.h"
TINT_INSTANTIATE_TYPEINFO(tint::transform::DecomposeMemoryAccess);
TINT_INSTANTIATE_TYPEINFO(tint::transform::DecomposeMemoryAccess::Intrinsic);
namespace tint {
namespace transform {
namespace {
/// Offset is a simple ast::Expression builder interface, used to build byte
/// offsets for storage and uniform buffer accesses.
struct Offset : Castable<Offset> {
/// @returns builds and returns the ast::Expression in `ctx.dst`
virtual const ast::Expression* Build(CloneContext& ctx) const = 0;
};
/// OffsetExpr is an implementation of Offset that clones and casts the given
/// expression to `u32`.
struct OffsetExpr : Offset {
const ast::Expression* const expr = nullptr;
explicit OffsetExpr(const ast::Expression* e) : expr(e) {}
const ast::Expression* Build(CloneContext& ctx) const override {
auto* type = ctx.src->Sem().Get(expr)->Type()->UnwrapRef();
auto* res = ctx.Clone(expr);
if (!type->Is<sem::U32>()) {
res = ctx.dst->Construct<ProgramBuilder::u32>(res);
}
return res;
}
};
/// OffsetLiteral is an implementation of Offset that constructs a u32 literal
/// value.
struct OffsetLiteral : Castable<OffsetLiteral, Offset> {
uint32_t const literal = 0;
explicit OffsetLiteral(uint32_t lit) : literal(lit) {}
const ast::Expression* Build(CloneContext& ctx) const override {
return ctx.dst->Expr(literal);
}
};
/// OffsetBinOp is an implementation of Offset that constructs a binary-op of
/// two Offsets.
struct OffsetBinOp : Offset {
ast::BinaryOp op;
Offset const* lhs = nullptr;
Offset const* rhs = nullptr;
const ast::Expression* Build(CloneContext& ctx) const override {
return ctx.dst->create<ast::BinaryExpression>(op, lhs->Build(ctx),
rhs->Build(ctx));
}
};
/// LoadStoreKey is the unordered map key to a load or store intrinsic.
struct LoadStoreKey {
ast::StorageClass const storage_class; // buffer storage class
sem::Type const* buf_ty = nullptr; // buffer type
sem::Type const* el_ty = nullptr; // element type
bool operator==(const LoadStoreKey& rhs) const {
return storage_class == rhs.storage_class && buf_ty == rhs.buf_ty &&
el_ty == rhs.el_ty;
}
struct Hasher {
inline std::size_t operator()(const LoadStoreKey& u) const {
return utils::Hash(u.storage_class, u.buf_ty, u.el_ty);
}
};
};
/// AtomicKey is the unordered map key to an atomic intrinsic.
struct AtomicKey {
sem::Type const* buf_ty = nullptr; // buffer type
sem::Type const* el_ty = nullptr; // element type
sem::IntrinsicType const op; // atomic op
bool operator==(const AtomicKey& rhs) const {
return buf_ty == rhs.buf_ty && el_ty == rhs.el_ty && op == rhs.op;
}
struct Hasher {
inline std::size_t operator()(const AtomicKey& u) const {
return utils::Hash(u.buf_ty, u.el_ty, u.op);
}
};
};
bool IntrinsicDataTypeFor(const sem::Type* ty,
DecomposeMemoryAccess::Intrinsic::DataType& out) {
if (ty->Is<sem::I32>()) {
out = DecomposeMemoryAccess::Intrinsic::DataType::kI32;
return true;
}
if (ty->Is<sem::U32>()) {
out = DecomposeMemoryAccess::Intrinsic::DataType::kU32;
return true;
}
if (ty->Is<sem::F32>()) {
out = DecomposeMemoryAccess::Intrinsic::DataType::kF32;
return true;
}
if (auto* vec = ty->As<sem::Vector>()) {
switch (vec->Width()) {
case 2:
if (vec->type()->Is<sem::I32>()) {
out = DecomposeMemoryAccess::Intrinsic::DataType::kVec2I32;
return true;
}
if (vec->type()->Is<sem::U32>()) {
out = DecomposeMemoryAccess::Intrinsic::DataType::kVec2U32;
return true;
}
if (vec->type()->Is<sem::F32>()) {
out = DecomposeMemoryAccess::Intrinsic::DataType::kVec2F32;
return true;
}
break;
case 3:
if (vec->type()->Is<sem::I32>()) {
out = DecomposeMemoryAccess::Intrinsic::DataType::kVec3I32;
return true;
}
if (vec->type()->Is<sem::U32>()) {
out = DecomposeMemoryAccess::Intrinsic::DataType::kVec3U32;
return true;
}
if (vec->type()->Is<sem::F32>()) {
out = DecomposeMemoryAccess::Intrinsic::DataType::kVec3F32;
return true;
}
break;
case 4:
if (vec->type()->Is<sem::I32>()) {
out = DecomposeMemoryAccess::Intrinsic::DataType::kVec4I32;
return true;
}
if (vec->type()->Is<sem::U32>()) {
out = DecomposeMemoryAccess::Intrinsic::DataType::kVec4U32;
return true;
}
if (vec->type()->Is<sem::F32>()) {
out = DecomposeMemoryAccess::Intrinsic::DataType::kVec4F32;
return true;
}
break;
}
return false;
}
return false;
}
/// @returns a DecomposeMemoryAccess::Intrinsic decoration that can be applied
/// to a stub function to load the type `ty`.
DecomposeMemoryAccess::Intrinsic* IntrinsicLoadFor(
ProgramBuilder* builder,
ast::StorageClass storage_class,
const sem::Type* ty) {
DecomposeMemoryAccess::Intrinsic::DataType type;
if (!IntrinsicDataTypeFor(ty, type)) {
return nullptr;
}
return builder->ASTNodes().Create<DecomposeMemoryAccess::Intrinsic>(
builder->ID(), DecomposeMemoryAccess::Intrinsic::Op::kLoad, storage_class,
type);
}
/// @returns a DecomposeMemoryAccess::Intrinsic decoration that can be applied
/// to a stub function to store the type `ty`.
DecomposeMemoryAccess::Intrinsic* IntrinsicStoreFor(
ProgramBuilder* builder,
ast::StorageClass storage_class,
const sem::Type* ty) {
DecomposeMemoryAccess::Intrinsic::DataType type;
if (!IntrinsicDataTypeFor(ty, type)) {
return nullptr;
}
return builder->ASTNodes().Create<DecomposeMemoryAccess::Intrinsic>(
builder->ID(), DecomposeMemoryAccess::Intrinsic::Op::kStore,
storage_class, type);
}
/// @returns a DecomposeMemoryAccess::Intrinsic decoration that can be applied
/// to a stub function for the atomic op and the type `ty`.
DecomposeMemoryAccess::Intrinsic* IntrinsicAtomicFor(ProgramBuilder* builder,
sem::IntrinsicType ity,
const sem::Type* ty) {
auto op = DecomposeMemoryAccess::Intrinsic::Op::kAtomicLoad;
switch (ity) {
case sem::IntrinsicType::kAtomicLoad:
op = DecomposeMemoryAccess::Intrinsic::Op::kAtomicLoad;
break;
case sem::IntrinsicType::kAtomicStore:
op = DecomposeMemoryAccess::Intrinsic::Op::kAtomicStore;
break;
case sem::IntrinsicType::kAtomicAdd:
op = DecomposeMemoryAccess::Intrinsic::Op::kAtomicAdd;
break;
case sem::IntrinsicType::kAtomicSub:
op = DecomposeMemoryAccess::Intrinsic::Op::kAtomicSub;
break;
case sem::IntrinsicType::kAtomicMax:
op = DecomposeMemoryAccess::Intrinsic::Op::kAtomicMax;
break;
case sem::IntrinsicType::kAtomicMin:
op = DecomposeMemoryAccess::Intrinsic::Op::kAtomicMin;
break;
case sem::IntrinsicType::kAtomicAnd:
op = DecomposeMemoryAccess::Intrinsic::Op::kAtomicAnd;
break;
case sem::IntrinsicType::kAtomicOr:
op = DecomposeMemoryAccess::Intrinsic::Op::kAtomicOr;
break;
case sem::IntrinsicType::kAtomicXor:
op = DecomposeMemoryAccess::Intrinsic::Op::kAtomicXor;
break;
case sem::IntrinsicType::kAtomicExchange:
op = DecomposeMemoryAccess::Intrinsic::Op::kAtomicExchange;
break;
case sem::IntrinsicType::kAtomicCompareExchangeWeak:
op = DecomposeMemoryAccess::Intrinsic::Op::kAtomicCompareExchangeWeak;
break;
default:
TINT_ICE(Transform, builder->Diagnostics())
<< "invalid IntrinsicType for DecomposeMemoryAccess::Intrinsic: "
<< ty->type_name();
break;
}
DecomposeMemoryAccess::Intrinsic::DataType type;
if (!IntrinsicDataTypeFor(ty, type)) {
return nullptr;
}
return builder->ASTNodes().Create<DecomposeMemoryAccess::Intrinsic>(
builder->ID(), op, ast::StorageClass::kStorage, type);
}
/// BufferAccess describes a single storage or uniform buffer access
struct BufferAccess {
sem::Expression const* var = nullptr; // Storage buffer variable
Offset const* offset = nullptr; // The byte offset on var
sem::Type const* type = nullptr; // The type of the access
operator bool() const { return var; } // Returns true if valid
};
/// Store describes a single storage or uniform buffer write
struct Store {
const ast::AssignmentStatement* assignment; // The AST assignment statement
BufferAccess target; // The target for the write
};
} // namespace
/// State holds the current transform state
struct DecomposeMemoryAccess::State {
/// The clone context
CloneContext& ctx;
/// Alias to `*ctx.dst`
ProgramBuilder& b;
/// Map of AST expression to storage or uniform buffer access
/// This map has entries added when encountered, and removed when outer
/// expressions chain the access.
/// Subset of #expression_order, as expressions are not removed from
/// #expression_order.
std::unordered_map<const ast::Expression*, BufferAccess> accesses;
/// The visited order of AST expressions (superset of #accesses)
std::vector<const ast::Expression*> expression_order;
/// [buffer-type, element-type] -> load function name
std::unordered_map<LoadStoreKey, Symbol, LoadStoreKey::Hasher> load_funcs;
/// [buffer-type, element-type] -> store function name
std::unordered_map<LoadStoreKey, Symbol, LoadStoreKey::Hasher> store_funcs;
/// [buffer-type, element-type, atomic-op] -> load function name
std::unordered_map<AtomicKey, Symbol, AtomicKey::Hasher> atomic_funcs;
/// List of storage or uniform buffer writes
std::vector<Store> stores;
/// Allocations for offsets
BlockAllocator<Offset> offsets_;
/// Constructor
/// @param context the CloneContext
explicit State(CloneContext& context) : ctx(context), b(*ctx.dst) {}
/// @param offset the offset value to wrap in an Offset
/// @returns an Offset for the given literal value
const Offset* ToOffset(uint32_t offset) {
return offsets_.Create<OffsetLiteral>(offset);
}
/// @param expr the expression to convert to an Offset
/// @returns an Offset for the given ast::Expression
const Offset* ToOffset(const ast::Expression* expr) {
if (auto* u32 = expr->As<ast::UintLiteralExpression>()) {
return offsets_.Create<OffsetLiteral>(u32->value);
} else if (auto* i32 = expr->As<ast::SintLiteralExpression>()) {
if (i32->value > 0) {
return offsets_.Create<OffsetLiteral>(i32->value);
}
}
return offsets_.Create<OffsetExpr>(expr);
}
/// @param offset the Offset that is returned
/// @returns the given offset (pass-through)
const Offset* ToOffset(const Offset* offset) { return offset; }
/// @param lhs_ the left-hand side of the add expression
/// @param rhs_ the right-hand side of the add expression
/// @return an Offset that is a sum of lhs and rhs, performing basic constant
/// folding if possible
template <typename LHS, typename RHS>
const Offset* Add(LHS&& lhs_, RHS&& rhs_) {
auto* lhs = ToOffset(std::forward<LHS>(lhs_));
auto* rhs = ToOffset(std::forward<RHS>(rhs_));
auto* lhs_lit = tint::As<OffsetLiteral>(lhs);
auto* rhs_lit = tint::As<OffsetLiteral>(rhs);
if (lhs_lit && lhs_lit->literal == 0) {
return rhs;
}
if (rhs_lit && rhs_lit->literal == 0) {
return lhs;
}
if (lhs_lit && rhs_lit) {
if (static_cast<uint64_t>(lhs_lit->literal) +
static_cast<uint64_t>(rhs_lit->literal) <=
0xffffffff) {
return offsets_.Create<OffsetLiteral>(lhs_lit->literal +
rhs_lit->literal);
}
}
auto* out = offsets_.Create<OffsetBinOp>();
out->op = ast::BinaryOp::kAdd;
out->lhs = lhs;
out->rhs = rhs;
return out;
}
/// @param lhs_ the left-hand side of the multiply expression
/// @param rhs_ the right-hand side of the multiply expression
/// @return an Offset that is the multiplication of lhs and rhs, performing
/// basic constant folding if possible
template <typename LHS, typename RHS>
const Offset* Mul(LHS&& lhs_, RHS&& rhs_) {
auto* lhs = ToOffset(std::forward<LHS>(lhs_));
auto* rhs = ToOffset(std::forward<RHS>(rhs_));
auto* lhs_lit = tint::As<OffsetLiteral>(lhs);
auto* rhs_lit = tint::As<OffsetLiteral>(rhs);
if (lhs_lit && lhs_lit->literal == 0) {
return offsets_.Create<OffsetLiteral>(0);
}
if (rhs_lit && rhs_lit->literal == 0) {
return offsets_.Create<OffsetLiteral>(0);
}
if (lhs_lit && lhs_lit->literal == 1) {
return rhs;
}
if (rhs_lit && rhs_lit->literal == 1) {
return lhs;
}
if (lhs_lit && rhs_lit) {
return offsets_.Create<OffsetLiteral>(lhs_lit->literal *
rhs_lit->literal);
}
auto* out = offsets_.Create<OffsetBinOp>();
out->op = ast::BinaryOp::kMultiply;
out->lhs = lhs;
out->rhs = rhs;
return out;
}
/// AddAccess() adds the `expr -> access` map item to #accesses, and `expr`
/// to #expression_order.
/// @param expr the expression that performs the access
/// @param access the access
void AddAccess(const ast::Expression* expr, const BufferAccess& access) {
TINT_ASSERT(Transform, access.type);
accesses.emplace(expr, access);
expression_order.emplace_back(expr);
}
/// TakeAccess() removes the `node` item from #accesses (if it exists),
/// returning the BufferAccess. If #accesses does not hold an item for
/// `node`, an invalid BufferAccess is returned.
/// @param node the expression that performed an access
/// @return the BufferAccess for the given expression
BufferAccess TakeAccess(const ast::Expression* node) {
auto lhs_it = accesses.find(node);
if (lhs_it == accesses.end()) {
return {};
}
auto access = lhs_it->second;
accesses.erase(node);
return access;
}
/// LoadFunc() returns a symbol to an intrinsic function that loads an element
/// of type `el_ty` from a storage or uniform buffer of type `buf_ty`.
/// The emitted function has the signature:
/// `fn load(buf : buf_ty, offset : u32) -> el_ty`
/// @param buf_ty the storage or uniform buffer type
/// @param el_ty the storage or uniform buffer element type
/// @param var_user the variable user
/// @return the name of the function that performs the load
Symbol LoadFunc(const sem::Type* buf_ty,
const sem::Type* el_ty,
const sem::VariableUser* var_user) {
auto storage_class = var_user->Variable()->StorageClass();
return utils::GetOrCreate(
load_funcs, LoadStoreKey{storage_class, buf_ty, el_ty}, [&] {
auto* buf_ast_ty = CreateASTTypeFor(ctx, buf_ty);
auto* disable_validation = b.Disable(
ast::DisabledValidation::kIgnoreConstructibleFunctionParameter);
ast::VariableList params = {
// Note: The buffer parameter requires the StorageClass in
// order for HLSL to emit this as a ByteAddressBuffer or cbuffer
// array.
b.create<ast::Variable>(b.Sym("buffer"), storage_class,
var_user->Variable()->Access(),
buf_ast_ty, true, nullptr,
ast::DecorationList{disable_validation}),
b.Param("offset", b.ty.u32()),
};
auto name = b.Sym();
if (auto* intrinsic =
IntrinsicLoadFor(ctx.dst, storage_class, el_ty)) {
auto* el_ast_ty = CreateASTTypeFor(ctx, el_ty);
auto* func = b.create<ast::Function>(
name, params, el_ast_ty, nullptr,
ast::DecorationList{
intrinsic,
b.Disable(ast::DisabledValidation::kFunctionHasNoBody),
},
ast::DecorationList{});
b.AST().AddFunction(func);
} else if (auto* arr_ty = el_ty->As<sem::Array>()) {
// fn load_func(buf : buf_ty, offset : u32) -> array<T, N> {
// var arr : array<T, N>;
// for (var i = 0u; i < array_count; i = i + 1) {
// arr[i] = el_load_func(buf, offset + i * array_stride)
// }
// return arr;
// }
auto load =
LoadFunc(buf_ty, arr_ty->ElemType()->UnwrapRef(), var_user);
auto* arr =
b.Var(b.Symbols().New("arr"), CreateASTTypeFor(ctx, arr_ty));
auto* i = b.Var(b.Symbols().New("i"), nullptr, b.Expr(0u));
auto* for_init = b.Decl(i);
auto* for_cond = b.create<ast::BinaryExpression>(
ast::BinaryOp::kLessThan, b.Expr(i), b.Expr(arr_ty->Count()));
auto* for_cont = b.Assign(i, b.Add(i, 1u));
auto* arr_el = b.IndexAccessor(arr, i);
auto* el_offset =
b.Add(b.Expr("offset"), b.Mul(i, arr_ty->Stride()));
auto* el_val = b.Call(load, "buffer", el_offset);
auto* for_loop = b.For(for_init, for_cond, for_cont,
b.Block(b.Assign(arr_el, el_val)));
b.Func(name, params, CreateASTTypeFor(ctx, arr_ty),
{
b.Decl(arr),
for_loop,
b.Return(arr),
});
} else {
ast::ExpressionList values;
if (auto* mat_ty = el_ty->As<sem::Matrix>()) {
auto* vec_ty = mat_ty->ColumnType();
Symbol load = LoadFunc(buf_ty, vec_ty, var_user);
for (uint32_t i = 0; i < mat_ty->columns(); i++) {
auto* offset = b.Add("offset", i * mat_ty->ColumnStride());
values.emplace_back(b.Call(load, "buffer", offset));
}
} else if (auto* str = el_ty->As<sem::Struct>()) {
for (auto* member : str->Members()) {
auto* offset = b.Add("offset", member->Offset());
Symbol load =
LoadFunc(buf_ty, member->Type()->UnwrapRef(), var_user);
values.emplace_back(b.Call(load, "buffer", offset));
}
}
b.Func(
name, params, CreateASTTypeFor(ctx, el_ty),
{
b.Return(b.Construct(CreateASTTypeFor(ctx, el_ty), values)),
});
}
return name;
});
}
/// StoreFunc() returns a symbol to an intrinsic function that stores an
/// element of type `el_ty` to a storage buffer of type `buf_ty`.
/// The function has the signature:
/// `fn store(buf : buf_ty, offset : u32, value : el_ty)`
/// @param buf_ty the storage buffer type
/// @param el_ty the storage buffer element type
/// @param var_user the variable user
/// @return the name of the function that performs the store
Symbol StoreFunc(const sem::Type* buf_ty,
const sem::Type* el_ty,
const sem::VariableUser* var_user) {
auto storage_class = var_user->Variable()->StorageClass();
return utils::GetOrCreate(
store_funcs, LoadStoreKey{storage_class, buf_ty, el_ty}, [&] {
auto* buf_ast_ty = CreateASTTypeFor(ctx, buf_ty);
auto* el_ast_ty = CreateASTTypeFor(ctx, el_ty);
auto* disable_validation = b.Disable(
ast::DisabledValidation::kIgnoreConstructibleFunctionParameter);
ast::VariableList params{
// Note: The buffer parameter requires the StorageClass in
// order for HLSL to emit this as a ByteAddressBuffer.
b.create<ast::Variable>(b.Sym("buffer"), storage_class,
var_user->Variable()->Access(),
buf_ast_ty, true, nullptr,
ast::DecorationList{disable_validation}),
b.Param("offset", b.ty.u32()),
b.Param("value", el_ast_ty),
};
auto name = b.Sym();
if (auto* intrinsic =
IntrinsicStoreFor(ctx.dst, storage_class, el_ty)) {
auto* func = b.create<ast::Function>(
name, params, b.ty.void_(), nullptr,
ast::DecorationList{
intrinsic,
b.Disable(ast::DisabledValidation::kFunctionHasNoBody),
},
ast::DecorationList{});
b.AST().AddFunction(func);
} else {
ast::StatementList body;
if (auto* arr_ty = el_ty->As<sem::Array>()) {
// fn store_func(buf : buf_ty, offset : u32, value : el_ty) {
// var array = value; // No dynamic indexing on constant arrays
// for (var i = 0u; i < array_count; i = i + 1) {
// arr[i] = el_store_func(buf, offset + i * array_stride,
// value[i])
// }
// return arr;
// }
auto* array =
b.Var(b.Symbols().New("array"), nullptr, b.Expr("value"));
auto store =
StoreFunc(buf_ty, arr_ty->ElemType()->UnwrapRef(), var_user);
auto* i = b.Var(b.Symbols().New("i"), nullptr, b.Expr(0u));
auto* for_init = b.Decl(i);
auto* for_cond = b.create<ast::BinaryExpression>(
ast::BinaryOp::kLessThan, b.Expr(i), b.Expr(arr_ty->Count()));
auto* for_cont = b.Assign(i, b.Add(i, 1u));
auto* arr_el = b.IndexAccessor(array, i);
auto* el_offset =
b.Add(b.Expr("offset"), b.Mul(i, arr_ty->Stride()));
auto* store_stmt =
b.CallStmt(b.Call(store, "buffer", el_offset, arr_el));
auto* for_loop =
b.For(for_init, for_cond, for_cont, b.Block(store_stmt));
body = {b.Decl(array), for_loop};
} else if (auto* mat_ty = el_ty->As<sem::Matrix>()) {
auto* vec_ty = mat_ty->ColumnType();
Symbol store = StoreFunc(buf_ty, vec_ty, var_user);
for (uint32_t i = 0; i < mat_ty->columns(); i++) {
auto* offset = b.Add("offset", i * mat_ty->ColumnStride());
auto* access = b.IndexAccessor("value", i);
auto* call = b.Call(store, "buffer", offset, access);
body.emplace_back(b.CallStmt(call));
}
} else if (auto* str = el_ty->As<sem::Struct>()) {
for (auto* member : str->Members()) {
auto* offset = b.Add("offset", member->Offset());
auto* access = b.MemberAccessor(
"value", ctx.Clone(member->Declaration()->symbol));
Symbol store =
StoreFunc(buf_ty, member->Type()->UnwrapRef(), var_user);
auto* call = b.Call(store, "buffer", offset, access);
body.emplace_back(b.CallStmt(call));
}
}
b.Func(name, params, b.ty.void_(), body);
}
return name;
});
}
/// AtomicFunc() returns a symbol to an intrinsic function that performs an
/// atomic operation from a storage buffer of type `buf_ty`. The function has
/// the signature:
// `fn atomic_op(buf : buf_ty, offset : u32, ...) -> T`
/// @param buf_ty the storage buffer type
/// @param el_ty the storage buffer element type
/// @param intrinsic the atomic intrinsic
/// @param var_user the variable user
/// @return the name of the function that performs the load
Symbol AtomicFunc(const sem::Type* buf_ty,
const sem::Type* el_ty,
const sem::Intrinsic* intrinsic,
const sem::VariableUser* var_user) {
auto op = intrinsic->Type();
return utils::GetOrCreate(atomic_funcs, AtomicKey{buf_ty, el_ty, op}, [&] {
auto* buf_ast_ty = CreateASTTypeFor(ctx, buf_ty);
auto* disable_validation = b.Disable(
ast::DisabledValidation::kIgnoreConstructibleFunctionParameter);
// The first parameter to all WGSL atomics is the expression to the
// atomic. This is replaced with two parameters: the buffer and offset.
ast::VariableList params = {
// Note: The buffer parameter requires the kStorage StorageClass in
// order for HLSL to emit this as a ByteAddressBuffer.
b.create<ast::Variable>(b.Sym("buffer"), ast::StorageClass::kStorage,
var_user->Variable()->Access(), buf_ast_ty,
true, nullptr,
ast::DecorationList{disable_validation}),
b.Param("offset", b.ty.u32()),
};
// Other parameters are copied as-is:
for (size_t i = 1; i < intrinsic->Parameters().size(); i++) {
auto* param = intrinsic->Parameters()[i];
auto* ty = CreateASTTypeFor(ctx, param->Type());
params.emplace_back(b.Param("param_" + std::to_string(i), ty));
}
auto* atomic = IntrinsicAtomicFor(ctx.dst, op, el_ty);
if (atomic == nullptr) {
TINT_ICE(Transform, b.Diagnostics())
<< "IntrinsicAtomicFor() returned nullptr for op " << op
<< " and type " << el_ty->type_name();
}
auto* ret_ty = CreateASTTypeFor(ctx, intrinsic->ReturnType());
auto* func = b.create<ast::Function>(
b.Sym(), params, ret_ty, nullptr,
ast::DecorationList{
atomic,
b.Disable(ast::DisabledValidation::kFunctionHasNoBody),
},
ast::DecorationList{});
b.AST().AddFunction(func);
return func->symbol;
});
}
};
DecomposeMemoryAccess::Intrinsic::Intrinsic(ProgramID pid,
Op o,
ast::StorageClass sc,
DataType ty)
: Base(pid), op(o), storage_class(sc), type(ty) {}
DecomposeMemoryAccess::Intrinsic::~Intrinsic() = default;
std::string DecomposeMemoryAccess::Intrinsic::InternalName() const {
std::stringstream ss;
switch (op) {
case Op::kLoad:
ss << "intrinsic_load_";
break;
case Op::kStore:
ss << "intrinsic_store_";
break;
case Op::kAtomicLoad:
ss << "intrinsic_atomic_load_";
break;
case Op::kAtomicStore:
ss << "intrinsic_atomic_store_";
break;
case Op::kAtomicAdd:
ss << "intrinsic_atomic_add_";
break;
case Op::kAtomicSub:
ss << "intrinsic_atomic_sub_";
break;
case Op::kAtomicMax:
ss << "intrinsic_atomic_max_";
break;
case Op::kAtomicMin:
ss << "intrinsic_atomic_min_";
break;
case Op::kAtomicAnd:
ss << "intrinsic_atomic_and_";
break;
case Op::kAtomicOr:
ss << "intrinsic_atomic_or_";
break;
case Op::kAtomicXor:
ss << "intrinsic_atomic_xor_";
break;
case Op::kAtomicExchange:
ss << "intrinsic_atomic_exchange_";
break;
case Op::kAtomicCompareExchangeWeak:
ss << "intrinsic_atomic_compare_exchange_weak_";
break;
}
ss << storage_class << "_";
switch (type) {
case DataType::kU32:
ss << "u32";
break;
case DataType::kF32:
ss << "f32";
break;
case DataType::kI32:
ss << "i32";
break;
case DataType::kVec2U32:
ss << "vec2_u32";
break;
case DataType::kVec2F32:
ss << "vec2_f32";
break;
case DataType::kVec2I32:
ss << "vec2_i32";
break;
case DataType::kVec3U32:
ss << "vec3_u32";
break;
case DataType::kVec3F32:
ss << "vec3_f32";
break;
case DataType::kVec3I32:
ss << "vec3_i32";
break;
case DataType::kVec4U32:
ss << "vec4_u32";
break;
case DataType::kVec4F32:
ss << "vec4_f32";
break;
case DataType::kVec4I32:
ss << "vec4_i32";
break;
}
return ss.str();
}
const DecomposeMemoryAccess::Intrinsic* DecomposeMemoryAccess::Intrinsic::Clone(
CloneContext* ctx) const {
return ctx->dst->ASTNodes().Create<DecomposeMemoryAccess::Intrinsic>(
ctx->dst->ID(), op, storage_class, type);
}
DecomposeMemoryAccess::DecomposeMemoryAccess() = default;
DecomposeMemoryAccess::~DecomposeMemoryAccess() = default;
bool DecomposeMemoryAccess::ShouldRun(const Program* program,
const DataMap&) const {
for (auto* decl : program->AST().GlobalDeclarations()) {
if (auto* var = program->Sem().Get<sem::Variable>(decl)) {
if (var->StorageClass() == ast::StorageClass::kStorage ||
var->StorageClass() == ast::StorageClass::kUniform) {
return true;
}
}
}
return false;
}
void DecomposeMemoryAccess::Run(CloneContext& ctx,
const DataMap&,
DataMap&) const {
auto& sem = ctx.src->Sem();
State state(ctx);
// Scan the AST nodes for storage and uniform buffer accesses. Complex
// expression chains (e.g. `storage_buffer.foo.bar[20].x`) are handled by
// maintaining an offset chain via the `state.TakeAccess()`,
// `state.AddAccess()` methods.
//
// Inner-most expression nodes are guaranteed to be visited first because AST
// nodes are fully immutable and require their children to be constructed
// first so their pointer can be passed to the parent's constructor.
for (auto* node : ctx.src->ASTNodes().Objects()) {
if (auto* ident = node->As<ast::IdentifierExpression>()) {
// X
if (auto* var = sem.Get<sem::VariableUser>(ident)) {
if (var->Variable()->StorageClass() == ast::StorageClass::kStorage ||
var->Variable()->StorageClass() == ast::StorageClass::kUniform) {
// Variable to a storage or uniform buffer
state.AddAccess(ident, {
var,
state.ToOffset(0u),
var->Type()->UnwrapRef(),
});
}
}
continue;
}
if (auto* accessor = node->As<ast::MemberAccessorExpression>()) {
// X.Y
auto* accessor_sem = sem.Get(accessor);
if (auto* swizzle = accessor_sem->As<sem::Swizzle>()) {
if (swizzle->Indices().size() == 1) {
if (auto access = state.TakeAccess(accessor->structure)) {
auto* vec_ty = access.type->As<sem::Vector>();
auto* offset =
state.Mul(vec_ty->type()->Size(), swizzle->Indices()[0]);
state.AddAccess(accessor, {
access.var,
state.Add(access.offset, offset),
vec_ty->type()->UnwrapRef(),
});
}
}
} else {
if (auto access = state.TakeAccess(accessor->structure)) {
auto* str_ty = access.type->As<sem::Struct>();
auto* member = str_ty->FindMember(accessor->member->symbol);
auto offset = member->Offset();
state.AddAccess(accessor, {
access.var,
state.Add(access.offset, offset),
member->Type()->UnwrapRef(),
});
}
}
continue;
}
if (auto* accessor = node->As<ast::IndexAccessorExpression>()) {
if (auto access = state.TakeAccess(accessor->object)) {
// X[Y]
if (auto* arr = access.type->As<sem::Array>()) {
auto* offset = state.Mul(arr->Stride(), accessor->index);
state.AddAccess(accessor, {
access.var,
state.Add(access.offset, offset),
arr->ElemType()->UnwrapRef(),
});
continue;
}
if (auto* vec_ty = access.type->As<sem::Vector>()) {
auto* offset = state.Mul(vec_ty->type()->Size(), accessor->index);
state.AddAccess(accessor, {
access.var,
state.Add(access.offset, offset),
vec_ty->type()->UnwrapRef(),
});
continue;
}
if (auto* mat_ty = access.type->As<sem::Matrix>()) {
auto* offset = state.Mul(mat_ty->ColumnStride(), accessor->index);
state.AddAccess(accessor, {
access.var,
state.Add(access.offset, offset),
mat_ty->ColumnType(),
});
continue;
}
}
}
if (auto* op = node->As<ast::UnaryOpExpression>()) {
if (op->op == ast::UnaryOp::kAddressOf) {
// &X
if (auto access = state.TakeAccess(op->expr)) {
// HLSL does not support pointers, so just take the access from the
// reference and place it on the pointer.
state.AddAccess(op, access);
continue;
}
}
}
if (auto* assign = node->As<ast::AssignmentStatement>()) {
// X = Y
// Move the LHS access to a store.
if (auto lhs = state.TakeAccess(assign->lhs)) {
state.stores.emplace_back(Store{assign, lhs});
}
}
if (auto* call_expr = node->As<ast::CallExpression>()) {
auto* call = sem.Get(call_expr);
if (auto* intrinsic = call->Target()->As<sem::Intrinsic>()) {
if (intrinsic->Type() == sem::IntrinsicType::kArrayLength) {
// arrayLength(X)
// Don't convert X into a load, this intrinsic actually requires the
// real pointer.
state.TakeAccess(call_expr->args[0]);
continue;
}
if (intrinsic->IsAtomic()) {
if (auto access = state.TakeAccess(call_expr->args[0])) {
// atomic___(X)
ctx.Replace(call_expr, [=, &ctx, &state] {
auto* buf = access.var->Declaration();
auto* offset = access.offset->Build(ctx);
auto* buf_ty = access.var->Type()->UnwrapRef();
auto* el_ty = access.type->UnwrapRef()->As<sem::Atomic>()->Type();
Symbol func =
state.AtomicFunc(buf_ty, el_ty, intrinsic,
access.var->As<sem::VariableUser>());
ast::ExpressionList args{ctx.Clone(buf), offset};
for (size_t i = 1; i < call_expr->args.size(); i++) {
auto* arg = call_expr->args[i];
args.emplace_back(ctx.Clone(arg));
}
return ctx.dst->Call(func, args);
});
}
}
}
}
}
// All remaining accesses are loads, transform these into calls to the
// corresponding load function
for (auto* expr : state.expression_order) {
auto access_it = state.accesses.find(expr);
if (access_it == state.accesses.end()) {
continue;
}
BufferAccess access = access_it->second;
ctx.Replace(expr, [=, &ctx, &state] {
auto* buf = access.var->Declaration();
auto* offset = access.offset->Build(ctx);
auto* buf_ty = access.var->Type()->UnwrapRef();
auto* el_ty = access.type->UnwrapRef();
Symbol func =
state.LoadFunc(buf_ty, el_ty, access.var->As<sem::VariableUser>());
return ctx.dst->Call(func, ctx.CloneWithoutTransform(buf), offset);
});
}
// And replace all storage and uniform buffer assignments with stores
for (auto store : state.stores) {
ctx.Replace(store.assignment, [=, &ctx, &state] {
auto* buf = store.target.var->Declaration();
auto* offset = store.target.offset->Build(ctx);
auto* buf_ty = store.target.var->Type()->UnwrapRef();
auto* el_ty = store.target.type->UnwrapRef();
auto* value = store.assignment->rhs;
Symbol func = state.StoreFunc(buf_ty, el_ty,
store.target.var->As<sem::VariableUser>());
auto* call = ctx.dst->Call(func, ctx.CloneWithoutTransform(buf), offset,
ctx.Clone(value));
return ctx.dst->CallStmt(call);
});
}
ctx.Clone();
}
} // namespace transform
} // namespace tint
TINT_INSTANTIATE_TYPEINFO(tint::transform::Offset);
TINT_INSTANTIATE_TYPEINFO(tint::transform::OffsetLiteral);