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// Copyright 2020 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.
#ifndef SRC_CLONE_CONTEXT_H_
#define SRC_CLONE_CONTEXT_H_
#include <algorithm>
#include <functional>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
#include "src/castable.h"
#include "src/debug.h"
#include "src/symbol.h"
#include "src/traits.h"
namespace tint {
// Forward declarations
class CloneContext;
class Program;
class ProgramBuilder;
namespace ast {
class FunctionList;
class Node;
} // namespace ast
ProgramID ProgramIDOf(const Program*);
ProgramID ProgramIDOf(const ast::Node*);
/// Cloneable is the base class for all objects that can be cloned
class Cloneable : public Castable<Cloneable> {
public:
/// Performs a deep clone of this object using the CloneContext `ctx`.
/// @param ctx the clone context
/// @return the newly cloned object
virtual Cloneable* Clone(CloneContext* ctx) const = 0;
};
/// @returns an invalid ProgramID
inline ProgramID ProgramIDOf(const Cloneable*) {
return ProgramID();
}
/// CloneContext holds the state used while cloning AST nodes.
class CloneContext {
/// ParamTypeIsPtrOf<F, T>::value is true iff the first parameter of
/// F is a pointer of (or derives from) type T.
template <typename F, typename T>
using ParamTypeIsPtrOf = traits::IsTypeOrDerived<
typename std::remove_pointer<traits::ParamTypeT<F, 0>>::type,
T>;
public:
/// SymbolTransform is a function that takes a symbol and returns a new
/// symbol.
using SymbolTransform = std::function<Symbol(Symbol)>;
/// Constructor for cloning objects from `from` into `to`.
/// @param to the target ProgramBuilder to clone into
/// @param from the source Program to clone from
/// @param auto_clone_symbols clone all symbols in `from` before returning
CloneContext(ProgramBuilder* to,
Program const* from,
bool auto_clone_symbols = true);
/// Constructor for cloning objects from and to the ProgramBuilder `builder`.
/// @param builder the ProgramBuilder
explicit CloneContext(ProgramBuilder* builder);
/// Destructor
~CloneContext();
/// Clones the Node or sem::Type `a` into the ProgramBuilder #dst if `a` is
/// not null. If `a` is null, then Clone() returns null. If `a` has been
/// cloned already by this CloneContext then the same cloned pointer is
/// returned.
///
/// Clone() may use a function registered with ReplaceAll() to create a
/// transformed version of the object. See ReplaceAll() for more information.
///
/// If the CloneContext is cloning from a Program to a ProgramBuilder, then
/// the Node or sem::Type `a` must be owned by the Program #src.
///
/// @param a the `Node` or `sem::Type` to clone
/// @return the cloned node
template <typename T>
T* Clone(T* a) {
// If the input is nullptr, there's nothing to clone - just return nullptr.
if (a == nullptr) {
return nullptr;
}
if (src) {
TINT_ASSERT_PROGRAM_IDS_EQUAL_IF_VALID(Clone, src, a);
}
// Was Replace() called for this object?
auto it = replacements_.find(a);
if (it != replacements_.end()) {
return CheckedCast<T>(it->second);
}
Cloneable* cloned = nullptr;
// Attempt to clone using the registered replacer functions.
auto& typeinfo = a->TypeInfo();
for (auto& transform : transforms_) {
if (!typeinfo.Is(*transform.typeinfo)) {
continue;
}
cloned = transform.function(a);
break;
}
if (!cloned) {
// No transform for this type, or the transform returned nullptr.
// Clone with T::Clone().
cloned = a->Clone(this);
}
auto* out = CheckedCast<T>(cloned);
TINT_ASSERT_PROGRAM_IDS_EQUAL_IF_VALID(Clone, dst, out);
return out;
}
/// Clones the Node or sem::Type `a` into the ProgramBuilder #dst if `a` is
/// not null. If `a` is null, then Clone() returns null. If `a` has been
/// cloned already by this CloneContext then the same cloned pointer is
/// returned.
///
/// Unlike Clone(), this method does not invoke or use any transformations
/// registered by ReplaceAll().
///
/// If the CloneContext is cloning from a Program to a ProgramBuilder, then
/// the Node or sem::Type `a` must be owned by the Program #src.
///
/// @param a the `Node` or `sem::Type` to clone
/// @return the cloned node
template <typename T>
T* CloneWithoutTransform(T* a) {
// If the input is nullptr, there's nothing to clone - just return nullptr.
if (a == nullptr) {
return nullptr;
}
if (src) {
TINT_ASSERT_PROGRAM_IDS_EQUAL_IF_VALID(Clone, src, a);
}
// Have we seen this object before? If so, return the previously cloned
// version instead of making yet another copy.
auto it = replacements_.find(a);
if (it != replacements_.end()) {
return CheckedCast<T>(it->second);
}
// First time clone and no replacer transforms matched.
// Clone with T::Clone().
auto* c = a->Clone(this);
replacements_.emplace(a, c);
return CheckedCast<T>(c);
}
/// Clones the Source `s` into #dst
/// TODO(bclayton) - Currently this 'clone' is a shallow copy. If/when
/// `Source.File`s are owned by the Program this should make a copy of the
/// file.
/// @param s the `Source` to clone
/// @return the cloned source
Source Clone(const Source& s) const { return s; }
/// Clones the Symbol `s` into #dst
///
/// The Symbol `s` must be owned by the Program #src.
///
/// @param s the Symbol to clone
/// @return the cloned source
Symbol Clone(Symbol s);
/// Clones each of the elements of the vector `v` into the ProgramBuilder
/// #dst.
///
/// All the elements of the vector `v` must be owned by the Program #src.
///
/// @param v the vector to clone
/// @return the cloned vector
template <typename T>
std::vector<T> Clone(const std::vector<T>& v) {
std::vector<T> out;
out.reserve(v.size());
for (auto& el : v) {
out.emplace_back(Clone(el));
}
return out;
}
/// Clones each of the elements of the vector `v` using the ProgramBuilder
/// #dst, inserting any additional elements into the list that were registered
/// with calls to InsertBefore().
///
/// All the elements of the vector `v` must be owned by the Program #src.
///
/// @param v the vector to clone
/// @return the cloned vector
template <typename T>
std::vector<T*> Clone(const std::vector<T*>& v) {
std::vector<T*> out;
Clone(out, v);
return out;
}
/// Clones each of the elements of the vector `from` into the vector `to`,
/// inserting any additional elements into the list that were registered with
/// calls to InsertBefore().
///
/// All the elements of the vector `from` must be owned by the Program #src.
///
/// @param from the vector to clone
/// @param to the cloned result
template <typename T>
void Clone(std::vector<T*>& to, const std::vector<T*>& from) {
to.reserve(from.size());
auto list_transform_it = list_transforms_.find(&from);
if (list_transform_it != list_transforms_.end()) {
const auto& transforms = list_transform_it->second;
for (auto* o : transforms.insert_front_) {
to.emplace_back(CheckedCast<T>(o));
}
for (auto& el : from) {
auto insert_before_it = transforms.insert_before_.find(el);
if (insert_before_it != transforms.insert_before_.end()) {
for (auto insert : insert_before_it->second) {
to.emplace_back(CheckedCast<T>(insert));
}
}
if (transforms.remove_.count(el) == 0) {
to.emplace_back(Clone(el));
}
auto insert_after_it = transforms.insert_after_.find(el);
if (insert_after_it != transforms.insert_after_.end()) {
for (auto insert : insert_after_it->second) {
to.emplace_back(CheckedCast<T>(insert));
}
}
}
for (auto* o : transforms.insert_back_) {
to.emplace_back(CheckedCast<T>(o));
}
} else {
for (auto& el : from) {
to.emplace_back(Clone(el));
}
}
}
/// Clones each of the elements of the vector `v` into the ProgramBuilder
/// #dst.
///
/// All the elements of the vector `v` must be owned by the Program #src.
///
/// @param v the vector to clone
/// @return the cloned vector
ast::FunctionList Clone(const ast::FunctionList& v);
/// ReplaceAll() registers `replacer` to be called whenever the Clone() method
/// is called with a Cloneable type that matches (or derives from) the type of
/// the single parameter of `replacer`.
/// The returned Cloneable of `replacer` will be used as the replacement for
/// all references to the object that's being cloned. This returned Cloneable
/// must be owned by the Program #dst.
///
/// `replacer` must be function-like with the signature: `T* (T*)`
/// where `T` is a type deriving from Cloneable.
///
/// If `replacer` returns a nullptr then Clone() will call `T::Clone()` to
/// clone the object.
///
/// Example:
///
/// ```
/// // Replace all ast::UintLiterals with the number 42
/// CloneCtx ctx(&out, in);
/// ctx.ReplaceAll([&] (ast::UintLiteral* l) {
/// return ctx->dst->create<ast::UintLiteral>(
/// ctx->Clone(l->source()),
/// ctx->Clone(l->type()),
/// 42);
/// });
/// ctx.Clone();
/// ```
///
/// @warning a single handler can only be registered for any given type.
/// Attempting to register two handlers for the same type will result in an
/// ICE.
/// @warning The replacement object must be of the correct type for all
/// references of the original object. A type mismatch will result in an
/// assertion in debug builds, and undefined behavior in release builds.
/// @param replacer a function or function-like object with the signature
/// `T* (T*)`, where `T` derives from Cloneable
/// @returns this CloneContext so calls can be chained
template <typename F>
traits::EnableIf<ParamTypeIsPtrOf<F, Cloneable>::value, CloneContext>&
ReplaceAll(F&& replacer) {
using TPtr = traits::ParamTypeT<F, 0>;
using T = typename std::remove_pointer<TPtr>::type;
for (auto& transform : transforms_) {
if (transform.typeinfo->Is(TypeInfo::Of<T>()) ||
TypeInfo::Of<T>().Is(*transform.typeinfo)) {
TINT_ICE(Clone, Diagnostics())
<< "ReplaceAll() called with a handler for type "
<< TypeInfo::Of<T>().name
<< " that is already handled by a handler for type "
<< transform.typeinfo->name;
return *this;
}
}
CloneableTransform transform;
transform.typeinfo = &TypeInfo::Of<T>();
transform.function = [=](Cloneable* in) { return replacer(in->As<T>()); };
transforms_.emplace_back(std::move(transform));
return *this;
}
/// ReplaceAll() registers `replacer` to be called whenever the Clone() method
/// is called with a Symbol.
/// The returned symbol of `replacer` will be used as the replacement for
/// all references to the symbol that's being cloned. This returned Symbol
/// must be owned by the Program #dst.
/// @param replacer a function the signature `Symbol(Symbol)`.
/// @warning a SymbolTransform can only be registered once. Attempting to
/// register a SymbolTransform more than once will result in an ICE.
/// @returns this CloneContext so calls can be chained
CloneContext& ReplaceAll(const SymbolTransform& replacer) {
if (symbol_transform_) {
TINT_ICE(Clone, Diagnostics())
<< "ReplaceAll(const SymbolTransform&) called "
"multiple times on the same CloneContext";
return *this;
}
symbol_transform_ = replacer;
return *this;
}
/// Replace replaces all occurrences of `what` in #src with `with` in #dst
/// when calling Clone().
/// @param what a pointer to the object in #src that will be replaced with
/// `with`
/// @param with a pointer to the replacement object owned by #dst that will be
/// used as a replacement for `what`
/// @warning The replacement object must be of the correct type for all
/// references of the original object. A type mismatch will result in an
/// assertion in debug builds, and undefined behavior in release builds.
/// @returns this CloneContext so calls can be chained
template <typename WHAT, typename WITH>
CloneContext& Replace(WHAT* what, WITH* with) {
TINT_ASSERT_PROGRAM_IDS_EQUAL_IF_VALID(Clone, src, what);
TINT_ASSERT_PROGRAM_IDS_EQUAL_IF_VALID(Clone, dst, with);
replacements_[what] = with;
return *this;
}
/// Removes `object` from the cloned copy of `vector`.
/// @param vector the vector in #src
/// @param object a pointer to the object in #src that will be omitted from
/// the cloned vector.
/// @returns this CloneContext so calls can be chained
template <typename T, typename OBJECT>
CloneContext& Remove(const std::vector<T>& vector, OBJECT* object) {
TINT_ASSERT_PROGRAM_IDS_EQUAL_IF_VALID(Clone, src, object);
if (std::find(vector.begin(), vector.end(), object) == vector.end()) {
TINT_ICE(Clone, Diagnostics())
<< "CloneContext::Remove() vector does not contain object";
return *this;
}
list_transforms_[&vector].remove_.emplace(object);
return *this;
}
/// Inserts `object` before any other objects of `vector`, when it is cloned.
/// @param vector the vector in #src
/// @param object a pointer to the object in #dst that will be inserted at the
/// front of the vector
/// @returns this CloneContext so calls can be chained
template <typename T, typename OBJECT>
CloneContext& InsertFront(const std::vector<T>& vector, OBJECT* object) {
TINT_ASSERT_PROGRAM_IDS_EQUAL_IF_VALID(Clone, dst, object);
auto& transforms = list_transforms_[&vector];
auto& list = transforms.insert_front_;
list.emplace_back(object);
return *this;
}
/// Inserts `object` after any other objects of `vector`, when it is cloned.
/// @param vector the vector in #src
/// @param object a pointer to the object in #dst that will be inserted at the
/// end of the vector
/// @returns this CloneContext so calls can be chained
template <typename T, typename OBJECT>
CloneContext& InsertBack(const std::vector<T>& vector, OBJECT* object) {
TINT_ASSERT_PROGRAM_IDS_EQUAL_IF_VALID(Clone, dst, object);
auto& transforms = list_transforms_[&vector];
auto& list = transforms.insert_back_;
list.emplace_back(object);
return *this;
}
/// Inserts `object` before `before` whenever `vector` is cloned.
/// @param vector the vector in #src
/// @param before a pointer to the object in #src
/// @param object a pointer to the object in #dst that will be inserted before
/// any occurrence of the clone of `before`
/// @returns this CloneContext so calls can be chained
template <typename T, typename BEFORE, typename OBJECT>
CloneContext& InsertBefore(const std::vector<T>& vector,
const BEFORE* before,
OBJECT* object) {
TINT_ASSERT_PROGRAM_IDS_EQUAL_IF_VALID(Clone, src, before);
TINT_ASSERT_PROGRAM_IDS_EQUAL_IF_VALID(Clone, dst, object);
if (std::find(vector.begin(), vector.end(), before) == vector.end()) {
TINT_ICE(Clone, Diagnostics())
<< "CloneContext::InsertBefore() vector does not contain before";
return *this;
}
auto& transforms = list_transforms_[&vector];
auto& list = transforms.insert_before_[before];
list.emplace_back(object);
return *this;
}
/// Inserts `object` after `after` whenever `vector` is cloned.
/// @param vector the vector in #src
/// @param after a pointer to the object in #src
/// @param object a pointer to the object in #dst that will be inserted after
/// any occurrence of the clone of `after`
/// @returns this CloneContext so calls can be chained
template <typename T, typename AFTER, typename OBJECT>
CloneContext& InsertAfter(const std::vector<T>& vector,
const AFTER* after,
OBJECT* object) {
TINT_ASSERT_PROGRAM_IDS_EQUAL_IF_VALID(Clone, src, after);
TINT_ASSERT_PROGRAM_IDS_EQUAL_IF_VALID(Clone, dst, object);
if (std::find(vector.begin(), vector.end(), after) == vector.end()) {
TINT_ICE(Clone, Diagnostics())
<< "CloneContext::InsertAfter() vector does not contain after";
return *this;
}
auto& transforms = list_transforms_[&vector];
auto& list = transforms.insert_after_[after];
list.emplace_back(object);
return *this;
}
/// Clone performs the clone of the Program's AST nodes, types and symbols
/// from #src to #dst. Semantic nodes are not cloned, as these will be rebuilt
/// when the ProgramBuilder #dst builds its Program.
void Clone();
/// The target ProgramBuilder to clone into.
ProgramBuilder* const dst;
/// The source Program to clone from.
Program const* const src;
private:
struct CloneableTransform {
/// Constructor
CloneableTransform();
/// Copy constructor
/// @param other the CloneableTransform to copy
CloneableTransform(const CloneableTransform& other);
/// Destructor
~CloneableTransform();
// TypeInfo of the Cloneable that the transform operates on
const TypeInfo* typeinfo;
std::function<Cloneable*(Cloneable*)> function;
};
CloneContext(const CloneContext&) = delete;
CloneContext& operator=(const CloneContext&) = delete;
/// Cast `obj` from type `FROM` to type `TO`, returning the cast object.
/// Reports an internal compiler error if the cast failed.
template <typename TO, typename FROM>
TO* CheckedCast(FROM* obj) {
if (TO* cast = As<TO>(obj)) {
return cast;
}
TINT_ICE(Clone, Diagnostics())
<< "Cloned object was not of the expected type\n"
<< "got: " << (obj ? obj->TypeInfo().name : "<null>") << "\n"
<< "expected: " << TypeInfo::Of<TO>().name;
return nullptr;
}
/// @returns the diagnostic list of #dst
diag::List& Diagnostics() const;
/// A vector of Cloneable*
using CloneableList = std::vector<Cloneable*>;
// Transformations to be applied to a list (vector)
struct ListTransforms {
/// Constructor
ListTransforms();
/// Destructor
~ListTransforms();
/// A map of object in #src to omit when cloned into #dst.
std::unordered_set<const Cloneable*> remove_;
/// A list of objects in #dst to insert before any others when the vector is
/// cloned.
CloneableList insert_front_;
/// A list of objects in #dst to insert befor after any others when the
/// vector is cloned.
CloneableList insert_back_;
/// A map of object in #src to the list of cloned objects in #dst.
/// Clone(const std::vector<T*>& v) will use this to insert the map-value
/// list into the target vector before cloning and inserting the map-key.
std::unordered_map<const Cloneable*, CloneableList> insert_before_;
/// A map of object in #src to the list of cloned objects in #dst.
/// Clone(const std::vector<T*>& v) will use this to insert the map-value
/// list into the target vector after cloning and inserting the map-key.
std::unordered_map<const Cloneable*, CloneableList> insert_after_;
};
/// A map of object in #src to their replacement in #dst
std::unordered_map<const Cloneable*, Cloneable*> replacements_;
/// A map of symbol in #src to their cloned equivalent in #dst
std::unordered_map<Symbol, Symbol> cloned_symbols_;
/// Cloneable transform functions registered with ReplaceAll()
std::vector<CloneableTransform> transforms_;
/// Map of std::vector pointer to transforms for that list
std::unordered_map<const void*, ListTransforms> list_transforms_;
/// Symbol transform registered with ReplaceAll()
SymbolTransform symbol_transform_;
};
} // namespace tint
#endif // SRC_CLONE_CONTEXT_H_