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| 1 | +//===-- lib/Semantics/rewrite-directives.cpp ------------------------------===// |
| 2 | +// |
| 3 | +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| 4 | +// See https://llvm.org/LICENSE.txt for license information. |
| 5 | +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| 6 | +// |
| 7 | +//===----------------------------------------------------------------------===// |
| 8 | + |
| 9 | +#include "rewrite-directives.h" |
| 10 | +#include "flang/Parser/parse-tree-visitor.h" |
| 11 | +#include "flang/Parser/parse-tree.h" |
| 12 | +#include "flang/Semantics/semantics.h" |
| 13 | +#include "flang/Semantics/symbol.h" |
| 14 | +#include "llvm/Frontend/OpenMP/OMP.h.inc" |
| 15 | +#include <list> |
| 16 | + |
| 17 | +namespace Fortran::semantics { |
| 18 | + |
| 19 | +using namespace parser::literals; |
| 20 | + |
| 21 | +class DirectiveRewriteMutator { |
| 22 | +public: |
| 23 | + explicit DirectiveRewriteMutator(SemanticsContext &context) |
| 24 | + : context_{context} {} |
| 25 | + |
| 26 | + // Default action for a parse tree node is to visit children. |
| 27 | + template <typename T> bool Pre(T &) { return true; } |
| 28 | + template <typename T> void Post(T &) {} |
| 29 | + |
| 30 | +protected: |
| 31 | + SemanticsContext &context_; |
| 32 | +}; |
| 33 | + |
| 34 | +// Rewrite atomic constructs to add an explicit memory ordering to all that do |
| 35 | +// not specify it, honoring in this way the `atomic_default_mem_order` clause of |
| 36 | +// the REQUIRES directive. |
| 37 | +class OmpRewriteMutator : public DirectiveRewriteMutator { |
| 38 | +public: |
| 39 | + explicit OmpRewriteMutator(SemanticsContext &context) |
| 40 | + : DirectiveRewriteMutator(context) {} |
| 41 | + |
| 42 | + template <typename T> bool Pre(T &) { return true; } |
| 43 | + template <typename T> void Post(T &) {} |
| 44 | + |
| 45 | + bool Pre(parser::OpenMPAtomicConstruct &); |
| 46 | + bool Pre(parser::OpenMPRequiresConstruct &); |
| 47 | + |
| 48 | +private: |
| 49 | + bool atomicDirectiveDefaultOrderFound_{false}; |
| 50 | +}; |
| 51 | + |
| 52 | +bool OmpRewriteMutator::Pre(parser::OpenMPAtomicConstruct &x) { |
| 53 | + // Find top-level parent of the operation. |
| 54 | + Symbol *topLevelParent{common::visit( |
| 55 | + [&](auto &atomic) { |
| 56 | + Symbol *symbol{nullptr}; |
| 57 | + Scope *scope{ |
| 58 | + &context_. FindScope(std::get<parser::Verbatim>(atomic. t). source)}; |
| 59 | + do { |
| 60 | + if (Symbol * parent{scope->symbol()}) { |
| 61 | + symbol = parent; |
| 62 | + } |
| 63 | + scope = &scope->parent(); |
| 64 | + } while (!scope->IsGlobal()); |
| 65 | + |
| 66 | + assert(symbol && |
| 67 | + "Atomic construct must be within a scope associated with a symbol"); |
| 68 | + return symbol; |
| 69 | + }, |
| 70 | + x.u)}; |
| 71 | + |
| 72 | + // Get the `atomic_default_mem_order` clause from the top-level parent. |
| 73 | + std::optional<common::OmpAtomicDefaultMemOrderType> defaultMemOrder; |
| 74 | + common::visit( |
| 75 | + [&](auto &details) { |
| 76 | + if constexpr (std::is_convertible_v<decltype(&details), |
| 77 | + WithOmpDeclarative *>) { |
| 78 | + if (details.has_ompAtomicDefaultMemOrder()) { |
| 79 | + defaultMemOrder = *details.ompAtomicDefaultMemOrder(); |
| 80 | + } |
| 81 | + } |
| 82 | + }, |
| 83 | + topLevelParent->details()); |
| 84 | + |
| 85 | + if (!defaultMemOrder) { |
| 86 | + return false; |
| 87 | + } |
| 88 | + |
| 89 | + auto findMemOrderClause = |
| 90 | + []( const std::list<parser::OmpAtomicClause> &clauses) { |
| 91 | + return std::find_if( |
| 92 | + clauses.begin(), clauses.end(), [](const auto &clause) { |
| 93 | + return std::get_if<parser::OmpMemoryOrderClause>( |
| 94 | + &clause.u); |
| 95 | + }) != clauses.end(); |
| 96 | + }; |
| 97 | + |
| 98 | + // Get the clause list to which the new memory order clause must be added, |
| 99 | + // only if there are no other memory order clauses present for this atomic |
| 100 | + // directive. |
| 101 | + std::list<parser::OmpAtomicClause> *clauseList = common::visit( |
| 102 | + common::visitors{[&](parser::OmpAtomic &atomicConstruct) { |
| 103 | + // OmpAtomic only has a single list of clauses. |
| 104 | + auto &clauses{std::get<parser::OmpAtomicClauseList>( |
| 105 | + atomicConstruct.t)}; |
| 106 | + return !findMemOrderClause(clauses.v) ? &clauses.v |
| 107 | + : nullptr; |
| 108 | + }, |
| 109 | + [&](auto &atomicConstruct) { |
| 110 | + // All other atomic constructs have two lists of clauses. |
| 111 | + auto &clausesLhs{std::get<0>(atomicConstruct.t)}; |
| 112 | + auto &clausesRhs{std::get<2>(atomicConstruct.t)}; |
| 113 | + return !findMemOrderClause(clausesLhs.v) && |
| 114 | + !findMemOrderClause(clausesRhs.v) |
| 115 | + ? &clausesRhs.v |
| 116 | + : nullptr; |
| 117 | + }}, |
| 118 | + x.u); |
| 119 | + |
| 120 | + // Add a memory order clause to the atomic directive. |
| 121 | + if (clauseList) { |
| 122 | + atomicDirectiveDefaultOrderFound_ = true; |
| 123 | + switch (*defaultMemOrder) { |
| 124 | + case common::OmpAtomicDefaultMemOrderType::AcqRel: |
| 125 | + clauseList-> emplace_back<parser::OmpMemoryOrderClause>( common::visit( |
| 126 | + common::visitors{[](parser::OmpAtomicRead &) -> parser::OmpClause { |
| 127 | + return parser::OmpClause::Acquire{}; |
| 128 | + }, |
| 129 | + [](parser::OmpAtomicCapture &) -> parser::OmpClause { |
| 130 | + return parser::OmpClause::AcqRel{}; |
| 131 | + }, |
| 132 | + [](auto &) -> parser::OmpClause { |
| 133 | + // parser::{OmpAtomic, OmpAtomicUpdate, OmpAtomicWrite} |
| 134 | + return parser::OmpClause::Release{}; |
| 135 | + }}, |
| 136 | + x.u)); |
| 137 | + break; |
| 138 | + case common::OmpAtomicDefaultMemOrderType::Relaxed: |
| 139 | + clauseList-> emplace_back<parser::OmpMemoryOrderClause>( |
| 140 | + parser::OmpClause{parser::OmpClause::Relaxed{}}); |
| 141 | + break; |
| 142 | + case common::OmpAtomicDefaultMemOrderType::SeqCst: |
| 143 | + clauseList-> emplace_back<parser::OmpMemoryOrderClause>( |
| 144 | + parser::OmpClause{parser::OmpClause::SeqCst{}}); |
| 145 | + break; |
| 146 | + } |
| 147 | + } |
| 148 | + |
| 149 | + return false; |
| 150 | +} |
| 151 | + |
| 152 | +bool OmpRewriteMutator::Pre(parser::OpenMPRequiresConstruct &x) { |
| 153 | + for (parser::OmpClause &clause : std::get<parser::OmpClauseList>(x. t). v) { |
| 154 | + if (std::holds_alternative<parser::OmpClause::AtomicDefaultMemOrder>( |
| 155 | + clause.u) && |
| 156 | + atomicDirectiveDefaultOrderFound_) { |
| 157 | + context_.Say(clause.source, |
| 158 | + "REQUIRES directive with '%s' clause found lexically after atomic " |
| 159 | + "operation without a memory order clause"_err_en_US, |
| 160 | + parser::ToUpperCaseLetters(llvm::omp::getOpenMPClauseName( |
| 161 | + llvm::omp::OMPC_atomic_default_mem_order) |
| 162 | + .str())); |
| 163 | + } |
| 164 | + } |
| 165 | + return false; |
| 166 | +} |
| 167 | + |
| 168 | +bool RewriteOmpParts(SemanticsContext &context, parser::Program &program) { |
| 169 | + if (!context.IsEnabled(common::LanguageFeature::OpenMP)) { |
| 170 | + return true; |
| 171 | + } |
| 172 | + OmpRewriteMutator ompMutator{context}; |
| 173 | + parser::Walk(program, ompMutator); |
| 174 | + return !context.AnyFatalError(); |
| 175 | +} |
| 176 | + |
| 177 | +} // namespace Fortran::semantics |
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