direct_variable_access.cc | Explore in Territory

// Copyright 2023 The Dawn & Tint Authors
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#include "src/tint/lang/core/ir/transform/direct_variable_access.h"

#include <string>
#include <utility>

#include "src/tint/lang/core/ir/builder.h"
#include "src/tint/lang/core/ir/clone_context.h"
#include "src/tint/lang/core/ir/module.h"
#include "src/tint/lang/core/ir/traverse.h"
#include "src/tint/lang/core/ir/user_call.h"
#include "src/tint/lang/core/ir/validator.h"
#include "src/tint/lang/core/ir/var.h"
#include "src/tint/utils/containers/reverse.h"

usingnamespacetint::core::fluent_types;     // NOLINT
usingnamespacetint::core::number_suffixes;  // NOLINT

namespace tint::core::ir::transform {
namespace {

/// An access root, originating from a module-scope var.
/// These roots are not passed by parameter, but instead the callee references the module-scope var
/// directly.
struct RootModuleScopeVar { … };

/// An access root, originating from a pointer parameter or function-scope var.
/// These roots are passed by pointer parameter.
struct RootPtrParameter { … };

/// An access root. Either a RootModuleScopeVar or RootPtrParameter.
AccessRoot;

/// MemberAccess is an access operator to a struct member.
struct MemberAccess { … };

/// IndexAccess is an access operator to an array element or matrix column.
/// The ordered list of indices is passed by parameter.
struct IndexAccess { … };

/// An access operation. Either a MemberAccess or IndexAccess.
AccessOp;

/// A AccessShape describes the static "path" from a root variable to an element within the
/// variable.
///
/// Functions that have pointer parameters which need transforming will be forked into one or more
/// 'variants'. Each variant has different AccessShapes for the pointer parameters - the transform
/// will only emit one variant when the shapes of the pointer parameter accesses match.
///
/// Array accessors index expressions are held externally to the AccessShape, so
/// AccessShape will be considered equal even if the array or matrix index values differ.
///
/// For example, consider the following:
///
/// ```
/// struct A {
///     x : array<i32, 8>,
///     y : u32,
/// };
/// struct B {
///     x : i32,
///     y : array<A, 4>
/// };
/// var<workgroup> C : B;
/// ```
///
/// The following AccessShape would describe the following:
///
/// +====================================+===============+=================================+
/// | AccessShape                        | Type          |  Expression                     |
/// +====================================+===============+=================================+
/// | [ Var 'C', MemberAccess 'x' ]      | i32           |  C.x                            |
/// +------------------------------------+---------------+---------------------------------+
/// | [ Var 'C', MemberAccess 'y' ]      | array<A, 4>   |  C.y                            |
/// +------------------------------------+---------------+---------------------------------+
/// | [ Var 'C', MemberAccess 'y',       | A             |  C.y[indices[0]]                |
/// |   IndexAccess ]                    |               |                                 |
/// +------------------------------------+---------------+---------------------------------+
/// | [ Var 'C', MemberAccess 'y',       | array<i32, 8> |  C.y[indices[0]].x              |
/// |   IndexAccess, MemberAccess 'x' ]  |               |                                 |
/// +------------------------------------+---------------+---------------------------------+
/// | [ Var 'C', MemberAccess 'y',       | i32           |  C.y[indices[0]].x[indices[1]]  |
/// |   IndexAccess, MemberAccess 'x',   |               |                                 |
/// |   IndexAccess ]                    |               |                                 |
/// +------------------------------------+---------------+---------------------------------+
/// | [ Var 'C', MemberAccess 'y',       | u32           |  C.y[indices[0]].y              |
/// |   IndexAccess, MemberAccess 'y' ]  |               |                                 |
/// +------------------------------------+---------------+---------------------------------+
///
/// Where: `indices` is the AccessChain::indices.
struct AccessShape { … };

/// AccessChain describes a chain of access expressions originating from a variable.
struct AccessChain { … };

/// A variant signature describes the access shape of all the function's pointer parameters.
/// This is a map of pointer parameter index to access shape.
VariantSignature;

/// FnInfo describes a function that has pointer parameters which need replacing.
/// This function will be replaced by zero, one or many variants. Each variant will have a unique
/// access shape for the function's the pointer arguments.
struct FnInfo { … };

/// FnVariant describes a unique variant of a function that has pointer parameters that need
/// replacing.
struct FnVariant { … };

/// PIMPL state for the transform.
struct State { … };

}  // namespace

Result<SuccessType> DirectVariableAccess(Module& ir, const DirectVariableAccessOptions& options) { … }

}  // namespace tint::core::ir::transform
chromium/third_party/dawn/src/tint/lang/core/ir/transform/direct_variable_access.cc
