[flang-commits] [flang] [llvm] [flang][OpenMP] Decompose compound constructs, do recursive lowering (PR #90098)
Sergio Afonso via flang-commits
flang-commits at lists.llvm.org
Tue May 7 04:58:06 PDT 2024
================
@@ -0,0 +1,1161 @@
+//===- ConstructDecompositionT.h -- Decomposing compound constructs -------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+// Given a compound construct with a set of clauses, generate the list of
+// constituent leaf constructs, each with a list of clauses that apply to it.
+//
+// Note: Clauses that are not originally present, but that are implied by the
+// OpenMP spec are materialized, and are present in the output.
+//
+// Note: Composite constructs will also be broken up into leaf constructs.
+// If composite constructs require processing as a whole, the lists of clauses
+// for each leaf constituent should be merged.
+//===----------------------------------------------------------------------===//
+#ifndef LLVM_FRONTEND_OPENMP_CONSTRUCTDECOMPOSITIONT_H
+#define LLVM_FRONTEND_OPENMP_CONSTRUCTDECOMPOSITIONT_H
+
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/iterator_range.h"
+#include "llvm/Frontend/OpenMP/ClauseT.h"
+#include "llvm/Frontend/OpenMP/OMP.h"
+
+#include <iterator>
+#include <list>
+#include <optional>
+#include <tuple>
+#include <type_traits>
+#include <unordered_map>
+#include <unordered_set>
+#include <utility>
+#include <variant>
+
+static inline llvm::ArrayRef<llvm::omp::Directive> getWorksharing() {
+ static llvm::omp::Directive worksharing[] = {
+ llvm::omp::Directive::OMPD_do, llvm::omp::Directive::OMPD_for,
+ llvm::omp::Directive::OMPD_scope, llvm::omp::Directive::OMPD_sections,
+ llvm::omp::Directive::OMPD_single, llvm::omp::Directive::OMPD_workshare,
+ };
+ return worksharing;
+}
+
+static inline llvm::ArrayRef<llvm::omp::Directive> getWorksharingLoop() {
+ static llvm::omp::Directive worksharingLoop[] = {
+ llvm::omp::Directive::OMPD_do,
+ llvm::omp::Directive::OMPD_for,
+ };
+ return worksharingLoop;
+}
+
+namespace detail {
+template <typename Container, typename Predicate>
+typename std::remove_reference_t<Container>::iterator
+find_unique(Container &&container, Predicate &&pred) {
+ auto first = std::find_if(container.begin(), container.end(), pred);
+ if (first == container.end())
+ return first;
+ auto second = std::find_if(std::next(first), container.end(), pred);
+ if (second == container.end())
+ return first;
+ return container.end();
+}
+
+} // namespace detail
+
+namespace tomp {
+
+// ClauseType - Either instance of ClauseT, or a type derived from ClauseT.
+//
+// This is the clause representation in the code using this infrastructure.
+//
+// HelperType - A class that implements two member functions:
+//
+// // Return the base object of the given object, if any.
+// std::optional<Object> getBaseObject(const Object &object) const
+// // Return the iteration variable of the outermost loop associated
+// // with the construct being worked on, if any.
+// std::optional<Object> getLoopIterVar() const
+template <typename ClauseType, typename HelperType>
+struct ConstructDecompositionT {
+ using ClauseTy = ClauseType;
+
+ using TypeTy = typename ClauseTy::TypeTy;
+ using IdTy = typename ClauseTy::IdTy;
+ using ExprTy = typename ClauseTy::ExprTy;
+ using HelperTy = HelperType;
+ using ObjectTy = tomp::ObjectT<IdTy, ExprTy>;
+
+ using ClauseSet = std::unordered_set<const ClauseTy *>;
+
+ ConstructDecompositionT(uint32_t ver, HelperType &hlp,
+ llvm::omp::Directive dir,
+ llvm::ArrayRef<ClauseTy> clauses)
+ : version(ver), construct(dir), helper(hlp) {
+ for (const ClauseTy &clause : clauses)
+ nodes.push_back(&clause);
+
+ bool success = split();
+ if (!success)
+ return;
+
+ // Copy the individual leaf directives with their clauses to the
+ // output list. Copy by value, since we don't own the storage
+ // with the input clauses, and the internal representation uses
+ // clause addresses.
+ for (auto &leaf : leafs) {
+ output.push_back({leaf.id});
+ auto &out = output.back();
+ for (const ClauseTy *c : leaf.clauses)
+ out.clauses.push_back(*c);
+ }
+ }
+
+ tomp::ListT<DirectiveWithClauses<ClauseType>> output;
+
+private:
+ bool split();
+
+ struct LeafReprInternal {
+ llvm::omp::Directive id = llvm::omp::Directive::OMPD_unknown;
+ tomp::type::ListT<const ClauseTy *> clauses;
+ };
+
+ LeafReprInternal *findDirective(llvm::omp::Directive dirId) {
+ auto found = llvm::find_if(
+ leafs, [&](const LeafReprInternal &leaf) { return leaf.id == dirId; });
+ return found != leafs.end() ? &*found : nullptr;
+ }
+
+ ClauseSet *findClausesWith(const ObjectTy &object) {
+ if (auto found = syms.find(object.id()); found != syms.end())
+ return &found->second;
+ return nullptr;
+ }
+
+ template <typename S>
+ ClauseTy *makeClause(llvm::omp::Clause clauseId, S &&specific) {
+ implicit.push_back(ClauseTy{clauseId, std::move(specific)});
+ return &implicit.back();
+ }
+
+ void addClauseSymsToMap(const ObjectTy &object, const ClauseTy *);
+ void addClauseSymsToMap(const tomp::ObjectListT<IdTy, ExprTy> &objects,
+ const ClauseTy *);
+ void addClauseSymsToMap(const TypeTy &item, const ClauseTy *);
+ void addClauseSymsToMap(const ExprTy &item, const ClauseTy *);
+ void addClauseSymsToMap(const tomp::clause::MapT<TypeTy, IdTy, ExprTy> &item,
+ const ClauseTy *);
+
+ template <typename U>
+ void addClauseSymsToMap(const std::optional<U> &item, const ClauseTy *);
+ template <typename U>
+ void addClauseSymsToMap(const tomp::ListT<U> &item, const ClauseTy *);
+ template <typename... U, size_t... Is>
+ void addClauseSymsToMap(const std::tuple<U...> &item, const ClauseTy *,
+ std::index_sequence<Is...> = {});
+ template <typename U>
+ std::enable_if_t<std::is_enum_v<llvm::remove_cvref_t<U>>, void>
+ addClauseSymsToMap(U &&item, const ClauseTy *);
+
+ template <typename U>
+ std::enable_if_t<llvm::remove_cvref_t<U>::EmptyTrait::value, void>
+ addClauseSymsToMap(U &&item, const ClauseTy *);
+
+ template <typename U>
+ std::enable_if_t<llvm::remove_cvref_t<U>::IncompleteTrait::value, void>
+ addClauseSymsToMap(U &&item, const ClauseTy *);
+
+ template <typename U>
+ std::enable_if_t<llvm::remove_cvref_t<U>::WrapperTrait::value, void>
+ addClauseSymsToMap(U &&item, const ClauseTy *);
+
+ template <typename U>
+ std::enable_if_t<llvm::remove_cvref_t<U>::TupleTrait::value, void>
+ addClauseSymsToMap(U &&item, const ClauseTy *);
+
+ template <typename U>
+ std::enable_if_t<llvm::remove_cvref_t<U>::UnionTrait::value, void>
+ addClauseSymsToMap(U &&item, const ClauseTy *);
+
+ // Apply a clause to the only directive that allows it. If there are no
+ // directives that allow it, or if there is more that one, do not apply
+ // anything and return false, otherwise return true.
+ bool applyToUnique(const ClauseTy *node);
+
+ // Apply a clause to the first directive in given range that allows it.
+ // If such a directive does not exist, return false, otherwise return true.
+ template <typename Iterator>
+ bool applyToFirst(const ClauseTy *node, llvm::iterator_range<Iterator> range);
+
+ // Apply a clause to the innermost directive that allows it. If such a
+ // directive does not exist, return false, otherwise return true.
+ bool applyToInnermost(const ClauseTy *node);
+
+ // Apply a clause to the outermost directive that allows it. If such a
+ // directive does not exist, return false, otherwise return true.
+ bool applyToOutermost(const ClauseTy *node);
+
+ template <typename Predicate>
+ bool applyIf(const ClauseTy *node, Predicate shouldApply);
+
+ bool applyToAll(const ClauseTy *node);
+
+ template <typename Clause>
+ bool applyClause(Clause &&clause, const ClauseTy *node);
+
+ bool applyClause(const tomp::clause::CollapseT<TypeTy, IdTy, ExprTy> &clause,
+ const ClauseTy *);
+ bool applyClause(const tomp::clause::PrivateT<TypeTy, IdTy, ExprTy> &clause,
+ const ClauseTy *);
+ bool
+ applyClause(const tomp::clause::FirstprivateT<TypeTy, IdTy, ExprTy> &clause,
+ const ClauseTy *);
+ bool
+ applyClause(const tomp::clause::LastprivateT<TypeTy, IdTy, ExprTy> &clause,
+ const ClauseTy *);
+ bool applyClause(const tomp::clause::SharedT<TypeTy, IdTy, ExprTy> &clause,
+ const ClauseTy *);
+ bool applyClause(const tomp::clause::DefaultT<TypeTy, IdTy, ExprTy> &clause,
+ const ClauseTy *);
+ bool
+ applyClause(const tomp::clause::ThreadLimitT<TypeTy, IdTy, ExprTy> &clause,
+ const ClauseTy *);
+ bool applyClause(const tomp::clause::OrderT<TypeTy, IdTy, ExprTy> &clause,
+ const ClauseTy *);
+ bool applyClause(const tomp::clause::AllocateT<TypeTy, IdTy, ExprTy> &clause,
+ const ClauseTy *);
+ bool applyClause(const tomp::clause::ReductionT<TypeTy, IdTy, ExprTy> &clause,
+ const ClauseTy *);
+ bool applyClause(const tomp::clause::IfT<TypeTy, IdTy, ExprTy> &clause,
+ const ClauseTy *);
+ bool applyClause(const tomp::clause::LinearT<TypeTy, IdTy, ExprTy> &clause,
+ const ClauseTy *);
+ bool applyClause(const tomp::clause::NowaitT<TypeTy, IdTy, ExprTy> &clause,
+ const ClauseTy *);
+
+ uint32_t version;
+ llvm::omp::Directive construct;
+ HelperType &helper;
+ ListT<LeafReprInternal> leafs;
+ tomp::ListT<const ClauseTy *> nodes;
+ std::list<ClauseTy> implicit; // Container for materialized implicit clauses.
+ // Inserting must preserve element addresses.
+ std::unordered_map<IdTy, ClauseSet> syms;
+ std::unordered_set<IdTy> mapBases;
+};
+
+// Deduction guide
+template <typename ClauseType, typename HelperType>
+ConstructDecompositionT(uint32_t, HelperType &, llvm::omp::Directive,
+ llvm::ArrayRef<ClauseType>)
+ -> ConstructDecompositionT<ClauseType, HelperType>;
+
+template <typename C, typename H>
+void ConstructDecompositionT<C, H>::addClauseSymsToMap(const ObjectTy &object,
+ const ClauseTy *node) {
+ syms[object.id()].insert(node);
+}
+
+template <typename C, typename H>
+void ConstructDecompositionT<C, H>::addClauseSymsToMap(
+ const tomp::ObjectListT<IdTy, ExprTy> &objects, const ClauseTy *node) {
+ for (auto &object : objects)
+ syms[object.id()].insert(node);
+}
+
+template <typename C, typename H>
+void ConstructDecompositionT<C, H>::addClauseSymsToMap(const TypeTy &item,
+ const ClauseTy *node) {
+ // Nothing to do for types.
+}
+
+template <typename C, typename H>
+void ConstructDecompositionT<C, H>::addClauseSymsToMap(const ExprTy &item,
+ const ClauseTy *node) {
+ // Nothing to do for expressions.
+}
+
+template <typename C, typename H>
+void ConstructDecompositionT<C, H>::addClauseSymsToMap(
+ const tomp::clause::MapT<TypeTy, IdTy, ExprTy> &item,
+ const ClauseTy *node) {
+ auto &objects = std::get<tomp::ObjectListT<IdTy, ExprTy>>(item.t);
+ addClauseSymsToMap(objects, node);
+ for (auto &object : objects) {
+ if (auto base = helper.getBaseObject(object))
+ mapBases.insert(base->id());
+ }
+}
+
+template <typename C, typename H>
+template <typename U>
+void ConstructDecompositionT<C, H>::addClauseSymsToMap(
+ const std::optional<U> &item, const ClauseTy *node) {
+ if (item)
+ addClauseSymsToMap(*item, node);
+}
+
+template <typename C, typename H>
+template <typename U>
+void ConstructDecompositionT<C, H>::addClauseSymsToMap(
+ const tomp::ListT<U> &item, const ClauseTy *node) {
+ for (auto &s : item)
+ addClauseSymsToMap(s, node);
+}
+
+template <typename C, typename H>
+template <typename... U, size_t... Is>
+void ConstructDecompositionT<C, H>::addClauseSymsToMap(
+ const std::tuple<U...> &item, const ClauseTy *node,
+ std::index_sequence<Is...>) {
+ (void)node; // Silence strange warning from GCC.
+ (addClauseSymsToMap(std::get<Is>(item), node), ...);
+}
+
+template <typename C, typename H>
+template <typename U>
+std::enable_if_t<std::is_enum_v<llvm::remove_cvref_t<U>>, void>
+ConstructDecompositionT<C, H>::addClauseSymsToMap(U &&item,
+ const ClauseTy *node) {
+ // Nothing to do for enums.
+}
+
+template <typename C, typename H>
+template <typename U>
+std::enable_if_t<llvm::remove_cvref_t<U>::EmptyTrait::value, void>
+ConstructDecompositionT<C, H>::addClauseSymsToMap(U &&item,
+ const ClauseTy *node) {
+ // Nothing to do for an empty class.
+}
+
+template <typename C, typename H>
+template <typename U>
+std::enable_if_t<llvm::remove_cvref_t<U>::IncompleteTrait::value, void>
+ConstructDecompositionT<C, H>::addClauseSymsToMap(U &&item,
+ const ClauseTy *node) {
+ // Nothing to do for an incomplete class (they're empty).
+}
+
+template <typename C, typename H>
+template <typename U>
+std::enable_if_t<llvm::remove_cvref_t<U>::WrapperTrait::value, void>
+ConstructDecompositionT<C, H>::addClauseSymsToMap(U &&item,
+ const ClauseTy *node) {
+ addClauseSymsToMap(item.v, node);
+}
+
+template <typename C, typename H>
+template <typename U>
+std::enable_if_t<llvm::remove_cvref_t<U>::TupleTrait::value, void>
+ConstructDecompositionT<C, H>::addClauseSymsToMap(U &&item,
+ const ClauseTy *node) {
+ constexpr size_t tuple_size =
+ std::tuple_size_v<llvm::remove_cvref_t<decltype(item.t)>>;
+ addClauseSymsToMap(item.t, node, std::make_index_sequence<tuple_size>{});
+}
+
+template <typename C, typename H>
+template <typename U>
+std::enable_if_t<llvm::remove_cvref_t<U>::UnionTrait::value, void>
+ConstructDecompositionT<C, H>::addClauseSymsToMap(U &&item,
+ const ClauseTy *node) {
+ std::visit([&](auto &&s) { addClauseSymsToMap(s, node); }, item.u);
+}
+
+// Apply a clause to the only directive that allows it. If there are no
+// directives that allow it, or if there is more that one, do not apply
+// anything and return false, otherwise return true.
+template <typename C, typename H>
+bool ConstructDecompositionT<C, H>::applyToUnique(const ClauseTy *node) {
+ auto unique = detail::find_unique(leafs, [=](const auto &dirInfo) {
+ return llvm::omp::isAllowedClauseForDirective(dirInfo.id, node->id,
+ version);
+ });
+
+ if (unique != leafs.end()) {
+ unique->clauses.push_back(node);
+ return true;
+ }
+ return false;
+}
+
+// Apply a clause to the first directive in given range that allows it.
+// If such a directive does not exist, return false, otherwise return true.
+template <typename C, typename H>
+template <typename Iterator>
+bool ConstructDecompositionT<C, H>::applyToFirst(
+ const ClauseTy *node, llvm::iterator_range<Iterator> range) {
+ if (range.empty())
+ return false;
+
+ for (auto &leaf : range) {
+ if (!llvm::omp::isAllowedClauseForDirective(leaf.id, node->id, version))
+ continue;
+ leaf.clauses.push_back(node);
+ return true;
+ }
+ return false;
+}
+
+// Apply a clause to the innermost directive that allows it. If such a
+// directive does not exist, return false, otherwise return true.
+template <typename C, typename H>
+bool ConstructDecompositionT<C, H>::applyToInnermost(const ClauseTy *node) {
+ return applyToFirst(node, llvm::reverse(leafs));
+}
+
+// Apply a clause to the outermost directive that allows it. If such a
+// directive does not exist, return false, otherwise return true.
+template <typename C, typename H>
+bool ConstructDecompositionT<C, H>::applyToOutermost(const ClauseTy *node) {
+ return applyToFirst(node, llvm::iterator_range(leafs));
+}
+
+template <typename C, typename H>
+template <typename Predicate>
+bool ConstructDecompositionT<C, H>::applyIf(const ClauseTy *node,
+ Predicate shouldApply) {
+ bool applied = false;
+ for (auto &leaf : leafs) {
+ if (!llvm::omp::isAllowedClauseForDirective(leaf.id, node->id, version))
+ continue;
+ if (!shouldApply(leaf))
+ continue;
+ leaf.clauses.push_back(node);
+ applied = true;
+ }
+
+ return applied;
+}
+
+template <typename C, typename H>
+bool ConstructDecompositionT<C, H>::applyToAll(const ClauseTy *node) {
+ return applyIf(node, [](auto) { return true; });
+}
+
+template <typename C, typename H>
+template <typename Clause>
+bool ConstructDecompositionT<C, H>::applyClause(Clause &&clause,
+ const ClauseTy *node) {
+ // The default behavior is to find the unique directive to which the
+ // given clause may be applied. If there are no such directives, or
+ // if there are multiple ones, flag an error.
+ // From "OpenMP Application Programming Interface", Version 5.2:
+ // S Some clauses are permitted only on a single leaf construct of the
+ // S combined or composite construct, in which case the effect is as if
+ // S the clause is applied to that specific construct. (p339, 31-33)
+ if (applyToUnique(node))
+ return true;
+
+ return false;
+}
+
+// COLLAPSE
+// [5.2:93:20-21]
+// Directives: distribute, do, for, loop, simd, taskloop
+//
+// [5.2:339:35]
+// (35) The collapse clause is applied once to the combined or composite
+// construct.
+template <typename C, typename H>
+bool ConstructDecompositionT<C, H>::applyClause(
+ const tomp::clause::CollapseT<TypeTy, IdTy, ExprTy> &clause,
+ const ClauseTy *node) {
+ // Apply "collapse" to the innermost directive. If it's not one that
+ // allows it flag an error.
+ if (!leafs.empty()) {
+ auto &last = leafs.back();
+
+ if (llvm::omp::isAllowedClauseForDirective(last.id, node->id, version)) {
+ last.clauses.push_back(node);
+ return true;
+ }
+ }
+
+ return false;
+}
+
+// PRIVATE
+// [5.2:111:5-7]
+// Directives: distribute, do, for, loop, parallel, scope, sections, simd,
+// single, target, task, taskloop, teams
+//
+// [5.2:340:1-2]
+// (1) The effect of the 1 private clause is as if it is applied only to the
+// innermost leaf construct that permits it.
+template <typename C, typename H>
+bool ConstructDecompositionT<C, H>::applyClause(
+ const tomp::clause::PrivateT<TypeTy, IdTy, ExprTy> &clause,
+ const ClauseTy *node) {
+ return applyToInnermost(node);
+}
+
+// FIRSTPRIVATE
+// [5.2:112:5-7]
+// Directives: distribute, do, for, parallel, scope, sections, single, target,
+// task, taskloop, teams
+//
+// [5.2:340:3-20]
+// (3) The effect of the firstprivate clause is as if it is applied to one or
+// more leaf constructs as follows:
+// (5) To the distribute construct if it is among the constituent constructs;
+// (6) To the teams construct if it is among the constituent constructs and the
+// distribute construct is not;
+// (8) To a worksharing construct that accepts the clause if one is among the
+// constituent constructs;
+// (9) To the taskloop construct if it is among the constituent constructs;
+// (10) To the parallel construct if it is among the constituent constructs and
+// neither a taskloop construct nor a worksharing construct that accepts
+// the clause is among them;
+// (12) To the target construct if it is among the constituent constructs and
+// the same list item neither appears in a lastprivate clause nor is the
+// base variable or base pointer of a list item that appears in a map
+// clause.
+//
+// (15) If the parallel construct is among the constituent constructs and the
+// effect is not as if the firstprivate clause is applied to it by the above
+// rules, then the effect is as if the shared clause with the same list item is
+// applied to the parallel construct.
+// (17) If the teams construct is among the constituent constructs and the
+// effect is not as if the firstprivate clause is applied to it by the above
+// rules, then the effect is as if the shared clause with the same list item is
+// applied to the teams construct.
+template <typename C, typename H>
+bool ConstructDecompositionT<C, H>::applyClause(
+ const tomp::clause::FirstprivateT<TypeTy, IdTy, ExprTy> &clause,
+ const ClauseTy *node) {
+ bool applied = false;
+
+ // [5.2:340:3-6]
+ auto hasDistribute = findDirective(llvm::omp::OMPD_distribute);
----------------
skatrak wrote:
Nit: Maybe rather than "hasXyz" it would be better to name these variables "xyzLeaf", just because when used they currently look like they should be booleans rather than pointers to structures.
https://github.com/llvm/llvm-project/pull/90098
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