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Add utilities for running modifications inside nested IR nodes (p4lan…
…g#4940) * Add ir-traversal Signed-off-by: Vladimír Štill <[email protected]> * Docs for ir-traversal Signed-off-by: Vladimír Štill <[email protected]> * Further docs tweaks Signed-off-by: Vladimír Štill <[email protected]> * Code tweaks Signed-off-by: Vladimír Štill <[email protected]> * Fix formatting Signed-off-by: Vladimír Štill <[email protected]> * Add tests, few fixes in impl Signed-off-by: Vladimír Štill <[email protected]> * Fix a typo & make lint happy Signed-off-by: Vladimír Štill <[email protected]> * Format Signed-off-by: Vladimir Still <[email protected]> * Put the namespace Detail into a separate file Signed-off-by: Vladimír Štill <[email protected]> * Exemplify IR::Traversal on few places in testgen Signed-off-by: Vladimír Štill <[email protected]> * Try using quote includes Signed-off-by: Vladimír Štill <[email protected]> --------- Signed-off-by: Vladimír Štill <[email protected]> Signed-off-by: Vladimir Still <[email protected]>
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| Original file line number | Diff line number | Diff line change |
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| /* | ||
| Copyright 2024-present Intel Corporation. | ||
| 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. | ||
| */ | ||
| /** | ||
| * \file | ||
| * \brief IR traversing utilities, internal implementation details, not to be used directly. | ||
| * \date 2024 | ||
| * \author Vladimír Štill | ||
| */ | ||
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| #ifndef IR_IR_TRAVERSAL_INTERNAL_H_ | ||
| #define IR_IR_TRAVERSAL_INTERNAL_H_ | ||
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| #include "lib/exceptions.h" | ||
| #include "lib/rtti_utils.h" | ||
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| #ifndef IR_IR_TRAVERSAL_INTERNAL_ENABLE | ||
| #error "This file must not be used directly" | ||
| #endif | ||
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| namespace P4::IR::Traversal::Detail { | ||
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| /// @brief Internal, don't use directly. | ||
| /// The class exists so that the functions can be mutually recursive. | ||
| struct Traverse { | ||
| template <typename Obj, typename T> | ||
| static const Obj *modify(const Obj *, Assign<const T *> asgn) { | ||
| static_assert(!std::is_const_v<Obj>, "Cannot modify constant object"); | ||
| return asgn.value; | ||
| } | ||
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| template <typename Obj, typename T> | ||
| static const Obj *modify(Obj *, Assign<const T *> asgn) { | ||
| static_assert(!std::is_const_v<Obj>, "Cannot modify constant object"); | ||
| return asgn.value; | ||
| } | ||
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| template <typename Obj, typename T> | ||
| static Obj *modify(Obj *obj, Assign<T> &&asgn) { | ||
| static_assert(!std::is_const_v<Obj>, "Cannot modify constant object"); | ||
| *obj = std::move(asgn.value); | ||
| return obj; | ||
| } | ||
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| template <typename Obj, typename T> | ||
| static Obj *modify(Obj *obj, const Assign<T> &asgn) { | ||
| static_assert(!std::is_const_v<Obj>, "Cannot modify constant object"); | ||
| *obj = asgn.value; | ||
| return obj; | ||
| } | ||
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| template <typename Obj, typename Fn> | ||
| static decltype(auto) modify(Obj *obj, Fn fn) { | ||
| static_assert(!std::is_const_v<Obj>, "Cannot modify constant object"); | ||
| return fn(obj); | ||
| } | ||
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| template <typename Obj, typename... Selectors> | ||
| static Obj *modify(Obj *obj, Index idx, Selectors &&...selectors) { | ||
| static_assert(!std::is_const_v<Obj>, "Cannot modify constant object"); | ||
| BUG_CHECK(obj->size() > idx.value, "Index %1% out of bounds of %2%", idx.value, obj); | ||
| modifyRef((*obj)[idx.value], std::forward<Selectors>(selectors)...); | ||
| return obj; | ||
| } | ||
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| template <typename Obj, typename To, typename... Selectors> | ||
| static To *modify(Obj *obj, RTTI::Detail::ToType<To> cast, Selectors &&...selectors) { | ||
| static_assert(!std::is_const_v<Obj>, "Cannot modify constant object"); | ||
| auto *casted = cast(obj); | ||
| BUG_CHECK(casted, "Cast of %1% failed", obj); | ||
| return modify(casted, std::forward<Selectors>(selectors)...); | ||
| } | ||
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| template <typename Obj, typename T, typename Sub, typename... Selectors> | ||
| static Obj *modify(Obj *obj, Sub T::*member, Selectors &&...selectors) { | ||
| static_assert(!std::is_const_v<Obj>, "Cannot modify constant object"); | ||
| modifyRef(obj->*member, std::forward<Selectors>(selectors)...); | ||
| return obj; | ||
| } | ||
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| template <typename T, typename... Selectors> | ||
| static void modifyRef(T &ref, Selectors &&...selectors) { | ||
| if constexpr (std::is_pointer_v<T>) { | ||
| ref = modify(ref->clone(), std::forward<Selectors>(selectors)...); | ||
| } else { | ||
| auto *res = modify(&ref, std::forward<Selectors>(selectors)...); | ||
| if (&ref != res) { | ||
| ref = *res; | ||
| } | ||
| } | ||
| } | ||
| }; | ||
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| } // namespace P4::IR::Traversal::Detail | ||
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| #endif // IR_IR_TRAVERSAL_INTERNAL_H_ |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,135 @@ | ||
| /* | ||
| Copyright 2024-present Intel Corporation. | ||
| 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. | ||
| */ | ||
| /** | ||
| * \file | ||
| * \brief IR traversing utilities. This is mainly useful for modifying a sub-component of an IR | ||
| * node. | ||
| * \date 2024 | ||
| * \author Vladimír Štill | ||
| */ | ||
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| #ifndef IR_IR_TRAVERSAL_H_ | ||
| #define IR_IR_TRAVERSAL_H_ | ||
| #define IR_IR_TRAVERSAL_INTERNAL_ENABLE | ||
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| #include <cstddef> | ||
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| namespace P4::IR::Traversal { | ||
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| /// @brief A selector used at the end of selector chain to assign to the current sub-object. | ||
| /// e.g. `modify(obj, &IR::AssignmentStatement::left, Assign(var))` will set the LHS of assignment. | ||
| /// @tparam T the parameter is usually derived by the C++ compiler. | ||
| template <typename T> | ||
| struct Assign { | ||
| explicit Assign(const T &value) : value(value) {} | ||
| T value; | ||
| }; | ||
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| /// @brief Select an index of a integer-indexed sub-object. %This is useful e.g. to select first | ||
| /// parameter of a method call and in similar cases involving @ref IR::Vector or @ref | ||
| /// IR::IndexedVector. | ||
| /// | ||
| /// @code | ||
| /// modify(mce, &IR::MethodCallExpression::arguments, Index(0), &IR::Argument::expression, | ||
| /// Assign(val)) | ||
| /// @endcode | ||
| /// This snippet assigns `val` into the first argument of a method call. | ||
| struct Index { | ||
| explicit Index(size_t value) : value(value) {} | ||
| size_t value; | ||
| }; | ||
|
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| } // namespace P4::IR::Traversal | ||
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| // Put the internals out of the main file to increase its readability. | ||
| #include "ir-traversal-internal.h" | ||
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| namespace P4::IR::Traversal { | ||
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| /// @brief Given an object @p obj and a series of selector (ending with a modifier), modify the @p | ||
| /// obj's sub object at the selected path. %This is useful for deeper modification of objects that | ||
| /// is not based on object types (in that case please use visitors) but on object structure (e.g. | ||
| /// member paths of C++ objects). | ||
| /// @param obj An object to modify. | ||
| /// @param ...selectors A series of selectors ending either with Assign, or with a modifier | ||
| /// function (typically a lambda). | ||
| /// @return Modified object. This will usually be the same object as @p obj (unless the only | ||
| /// selector is Assign with a pointer). | ||
| /// | ||
| /// @section sec_selectors Path Selectors | ||
| /// | ||
| /// Selection of the sub-objects is perfomed mainly using member pointers, but other selectors are | ||
| /// also possible. | ||
| /// | ||
| /// - Object member pointer (e.g. `&IR::Expression::type`, `&IR::AssignmentStatement::left`) -- | ||
| /// these are used to select members of object. Note that since the IR sometimes uses inline | ||
| /// members and sometimes uses pointer members these are transparently handled the same -- this | ||
| /// behaves as-if at any point the current object was a pointer to value that is to be processed | ||
| /// by the following selectors. | ||
| /// - @ref `IR::Traversal::Index` -- used for indexing e.g. @ref `IR::Vector` or @ref | ||
| /// `IR::IndexedVector`. | ||
| /// - @ref `RTTI::to<T>` -- used to cast to a more specific type. This is necessary to access | ||
| /// members of the more specific type (e.g. if you know that a RHS of `IR::AssignmentStatement` is | ||
| /// `IR::Lss`, you can use `RTTI::to<IR::Lss>` and then access members of `IR::Lss`. Note that the | ||
| /// cast is not applied to anything -- we are passing a cast object. | ||
| /// | ||
| /// @section sec_modifiers Modifiers | ||
| /// | ||
| /// Modifier is a last component of the chain, it modifies the selected object. | ||
| /// - @ref `Traversal::Assign` -- a simple modifier that assigns/replaces the currently selected | ||
| /// value. If the argument is a pointer, the value is replaced, if the argument is non-pointer, | ||
| /// the selected value is assigned. | ||
| /// - freeform modifier object -- usually a lambda. This object will receive pointer to non-const | ||
| /// value of the currently selected object and can modify it in any way (e.g. increment value). | ||
| /// | ||
| /// For example, given an extern call, you can modify the type of the first argument by adding a | ||
| /// cast to it like this: | ||
| /// @code | ||
| /// modify(call, &IR::MethodCallStatement::methodCall, &IR::MethodCallExpression::arguments, | ||
| /// Index(0), &IR::Argument::expression, [&](const IR::Expression *expr) | ||
| /// { | ||
| /// return new IR::Cast(expr->srcInfo, idxType, expr); | ||
| /// }); | ||
| /// @endcode | ||
| /// | ||
| /// Similarly, you can set the type of the first argument in the type of the extern like this: | ||
| /// @code | ||
| /// modify(call, &IR::MethodCallStatement::methodCall, &IR::MethodCallExpression::method, | ||
| /// &IR::Expression::type, RTTI::to<IR::Type_Method>, &IR::Type_Method::parameters, | ||
| /// &IR::ParameterList::parameters, Index(0), &IR::Parameter::type, Assign(idxType)); | ||
| /// @endcode | ||
| /// | ||
| /// Any time a cast fails or an index is out of range the modification triggers a `BUG`. | ||
| /// | ||
| /// Please note that any modification is applied only to the selected path, that is, if the same | ||
| /// node occurs multiple times in the IR DAG, and one of them is "focused" by the selector and | ||
| /// modified, the other instance is unchanged (because the "focused" instance is cloned). | ||
| template <typename Obj, typename... Selectors> | ||
| Obj *modify(Obj *obj, Selectors &&...selectors) { | ||
| return Detail::Traverse::modify(obj, std::forward<Selectors>(selectors)...); | ||
| } | ||
|
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| /// @brief Similar to modify, but accepts constant argument which is cloned. Therefore, the result | ||
| /// is a different object then @p obj. @sa `Traversal::modify`. | ||
| template <typename Obj, typename... Selectors> | ||
| Obj *apply(const Obj *obj, Selectors &&...selectors) { | ||
| return Detail::Traverse::modify(obj->clone(), std::forward<Selectors>(selectors)...); | ||
| } | ||
|
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| } // namespace P4::IR::Traversal | ||
|
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| #undef IR_IR_TRAVERSAL_INTERNAL_ENABLE | ||
| #endif // IR_IR_TRAVERSAL_H_ |
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