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llvm-project/flang/lib/Lower/PFTBuilder.cpp

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//===-- PFTBuilder.cpp ----------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "flang/Lower/PFTBuilder.h"
#include "flang/Lower/IntervalSet.h"
#include "flang/Lower/Support/Utils.h"
#include "flang/Parser/dump-parse-tree.h"
#include "flang/Parser/parse-tree-visitor.h"
#include "flang/Semantics/semantics.h"
#include "flang/Semantics/tools.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/IntervalMap.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#define DEBUG_TYPE "flang-pft"
static llvm::cl::opt<bool> clDisableStructuredFir(
"no-structured-fir", llvm::cl::desc("disable generation of structured FIR"),
llvm::cl::init(false), llvm::cl::Hidden);
static llvm::cl::opt<bool> nonRecursiveProcedures(
"non-recursive-procedures",
llvm::cl::desc("Make procedures non-recursive by default. This was the "
"default for all Fortran standards prior to 2018."),
llvm::cl::init(/*2018 standard=*/false));
using namespace Fortran;
namespace {
/// Helpers to unveil parser node inside Fortran::parser::Statement<>,
/// Fortran::parser::UnlabeledStatement, and Fortran::common::Indirection<>
template <typename A>
struct RemoveIndirectionHelper {
using Type = A;
};
template <typename A>
struct RemoveIndirectionHelper<common::Indirection<A>> {
using Type = A;
};
template <typename A>
struct UnwrapStmt {
static constexpr bool isStmt{false};
};
template <typename A>
struct UnwrapStmt<parser::Statement<A>> {
static constexpr bool isStmt{true};
using Type = typename RemoveIndirectionHelper<A>::Type;
constexpr UnwrapStmt(const parser::Statement<A> &a)
: unwrapped{removeIndirection(a.statement)}, position{a.source},
label{a.label} {}
const Type &unwrapped;
parser::CharBlock position;
std::optional<parser::Label> label;
};
template <typename A>
struct UnwrapStmt<parser::UnlabeledStatement<A>> {
static constexpr bool isStmt{true};
using Type = typename RemoveIndirectionHelper<A>::Type;
constexpr UnwrapStmt(const parser::UnlabeledStatement<A> &a)
: unwrapped{removeIndirection(a.statement)}, position{a.source} {}
const Type &unwrapped;
parser::CharBlock position;
std::optional<parser::Label> label;
};
/// The instantiation of a parse tree visitor (Pre and Post) is extremely
/// expensive in terms of compile and link time. So one goal here is to
/// limit the bridge to one such instantiation.
class PFTBuilder {
public:
PFTBuilder(const semantics::SemanticsContext &semanticsContext)
: pgm{std::make_unique<lower::pft::Program>()}, semanticsContext{
semanticsContext} {
lower::pft::PftNode pftRoot{*pgm.get()};
pftParentStack.push_back(pftRoot);
}
/// Get the result
std::unique_ptr<lower::pft::Program> result() { return std::move(pgm); }
template <typename A>
constexpr bool Pre(const A &a) {
if constexpr (lower::pft::isFunctionLike<A>) {
return enterFunction(a, semanticsContext);
} else if constexpr (lower::pft::isConstruct<A> ||
lower::pft::isDirective<A>) {
return enterConstructOrDirective(a);
} else if constexpr (UnwrapStmt<A>::isStmt) {
using T = typename UnwrapStmt<A>::Type;
// Node "a" being visited has one of the following types:
// Statement<T>, Statement<Indirection<T>>, UnlabeledStatement<T>,
// or UnlabeledStatement<Indirection<T>>
auto stmt{UnwrapStmt<A>(a)};
if constexpr (lower::pft::isConstructStmt<T> ||
lower::pft::isOtherStmt<T>) {
addEvaluation(lower::pft::Evaluation{
stmt.unwrapped, pftParentStack.back(), stmt.position, stmt.label});
return false;
} else if constexpr (std::is_same_v<T, parser::ActionStmt>) {
return std::visit(
common::visitors{
[&](const common::Indirection<parser::IfStmt> &x) {
convertIfStmt(x.value(), stmt.position, stmt.label);
return false;
},
[&](const auto &x) {
addEvaluation(lower::pft::Evaluation{
removeIndirection(x), pftParentStack.back(),
stmt.position, stmt.label});
return true;
},
},
stmt.unwrapped.u);
}
}
return true;
}
/// Convert an IfStmt into an IfConstruct, retaining the IfStmt as the
/// first statement of the construct.
void convertIfStmt(const parser::IfStmt &ifStmt, parser::CharBlock position,
std::optional<parser::Label> label) {
// Generate a skeleton IfConstruct parse node. Its components are never
// referenced. The actual components are available via the IfConstruct
// evaluation's nested evaluationList, with the ifStmt in the position of
// the otherwise normal IfThenStmt. Caution: All other PFT nodes reference
// front end generated parse nodes; this is an exceptional case.
static const auto ifConstruct = parser::IfConstruct{
parser::Statement<parser::IfThenStmt>{
std::nullopt,
parser::IfThenStmt{
std::optional<parser::Name>{},
parser::ScalarLogicalExpr{parser::LogicalExpr{parser::Expr{
parser::LiteralConstant{parser::LogicalLiteralConstant{
false, std::optional<parser::KindParam>{}}}}}}}},
parser::Block{}, std::list<parser::IfConstruct::ElseIfBlock>{},
std::optional<parser::IfConstruct::ElseBlock>{},
parser::Statement<parser::EndIfStmt>{std::nullopt,
parser::EndIfStmt{std::nullopt}}};
enterConstructOrDirective(ifConstruct);
addEvaluation(
lower::pft::Evaluation{ifStmt, pftParentStack.back(), position, label});
Pre(std::get<parser::UnlabeledStatement<parser::ActionStmt>>(ifStmt.t));
static const auto endIfStmt = parser::EndIfStmt{std::nullopt};
addEvaluation(
lower::pft::Evaluation{endIfStmt, pftParentStack.back(), {}, {}});
exitConstructOrDirective();
}
template <typename A>
constexpr void Post(const A &) {
if constexpr (lower::pft::isFunctionLike<A>) {
exitFunction();
} else if constexpr (lower::pft::isConstruct<A> ||
lower::pft::isDirective<A>) {
exitConstructOrDirective();
}
}
// Module like
bool Pre(const parser::Module &node) { return enterModule(node); }
bool Pre(const parser::Submodule &node) { return enterModule(node); }
void Post(const parser::Module &) { exitModule(); }
void Post(const parser::Submodule &) { exitModule(); }
// Block data
bool Pre(const parser::BlockData &node) {
addUnit(lower::pft::BlockDataUnit{node, pftParentStack.back(),
semanticsContext});
return false;
}
// Get rid of production wrapper
bool Pre(const parser::Statement<parser::ForallAssignmentStmt> &statement) {
addEvaluation(std::visit(
[&](const auto &x) {
return lower::pft::Evaluation{x, pftParentStack.back(),
statement.source, statement.label};
},
statement.statement.u));
return false;
}
bool Pre(const parser::WhereBodyConstruct &whereBody) {
return std::visit(
common::visitors{
[&](const parser::Statement<parser::AssignmentStmt> &stmt) {
// Not caught as other AssignmentStmt because it is not
// wrapped in a parser::ActionStmt.
addEvaluation(lower::pft::Evaluation{stmt.statement,
pftParentStack.back(),
stmt.source, stmt.label});
return false;
},
[&](const auto &) { return true; },
},
whereBody.u);
}
// CompilerDirective have special handling in case they are top level
// directives (i.e. they do not belong to a ProgramUnit).
bool Pre(const parser::CompilerDirective &directive) {
assert(pftParentStack.size() > 0 &&
"At least the Program must be a parent");
if (pftParentStack.back().isA<lower::pft::Program>()) {
addUnit(
lower::pft::CompilerDirectiveUnit(directive, pftParentStack.back()));
return false;
}
return enterConstructOrDirective(directive);
}
private:
/// Initialize a new module-like unit and make it the builder's focus.
template <typename A>
bool enterModule(const A &func) {
Fortran::lower::pft::ModuleLikeUnit &unit =
addUnit(lower::pft::ModuleLikeUnit{func, pftParentStack.back()});
functionList = &unit.nestedFunctions;
pushEvaluationList(&unit.evaluationList);
pftParentStack.emplace_back(unit);
return true;
}
void exitModule() {
if (!evaluationListStack.empty())
popEvaluationList();
pftParentStack.pop_back();
resetFunctionState();
}
/// Add the end statement Evaluation of a sub/program to the PFT.
/// There may be intervening internal subprogram definitions between
/// prior statements and this end statement.
void endFunctionBody() {
if (evaluationListStack.empty())
return;
auto evaluationList = evaluationListStack.back();
if (evaluationList->empty() || !evaluationList->back().isEndStmt()) {
const auto &endStmt =
pftParentStack.back().get<lower::pft::FunctionLikeUnit>().endStmt;
endStmt.visit(common::visitors{
[&](const parser::Statement<parser::EndProgramStmt> &s) {
addEvaluation(lower::pft::Evaluation{
s.statement, pftParentStack.back(), s.source, s.label});
},
[&](const parser::Statement<parser::EndFunctionStmt> &s) {
addEvaluation(lower::pft::Evaluation{
s.statement, pftParentStack.back(), s.source, s.label});
},
[&](const parser::Statement<parser::EndSubroutineStmt> &s) {
addEvaluation(lower::pft::Evaluation{
s.statement, pftParentStack.back(), s.source, s.label});
},
[&](const parser::Statement<parser::EndMpSubprogramStmt> &s) {
addEvaluation(lower::pft::Evaluation{
s.statement, pftParentStack.back(), s.source, s.label});
},
[&](const auto &s) {
llvm::report_fatal_error("missing end statement or unexpected "
"begin statement reference");
},
});
}
lastLexicalEvaluation = nullptr;
}
/// Pop the ModuleLikeUnit evaluationList when entering the first module
/// procedure.
void cleanModuleEvaluationList() {
if (evaluationListStack.empty())
return;
if (pftParentStack.back().isA<lower::pft::ModuleLikeUnit>())
popEvaluationList();
}
/// Initialize a new function-like unit and make it the builder's focus.
template <typename A>
bool enterFunction(const A &func,
const semantics::SemanticsContext &semanticsContext) {
cleanModuleEvaluationList();
endFunctionBody(); // enclosing host subprogram body, if any
Fortran::lower::pft::FunctionLikeUnit &unit =
addFunction(lower::pft::FunctionLikeUnit{func, pftParentStack.back(),
semanticsContext});
labelEvaluationMap = &unit.labelEvaluationMap;
assignSymbolLabelMap = &unit.assignSymbolLabelMap;
functionList = &unit.nestedFunctions;
pushEvaluationList(&unit.evaluationList);
pftParentStack.emplace_back(unit);
return true;
}
void exitFunction() {
rewriteIfGotos();
endFunctionBody();
analyzeBranches(nullptr, *evaluationListStack.back()); // add branch links
processEntryPoints();
popEvaluationList();
labelEvaluationMap = nullptr;
assignSymbolLabelMap = nullptr;
pftParentStack.pop_back();
resetFunctionState();
}
/// Initialize a new construct or directive and make it the builder's focus.
template <typename A>
bool enterConstructOrDirective(const A &constructOrDirective) {
Fortran::lower::pft::Evaluation &eval = addEvaluation(
lower::pft::Evaluation{constructOrDirective, pftParentStack.back()});
eval.evaluationList.reset(new lower::pft::EvaluationList);
pushEvaluationList(eval.evaluationList.get());
pftParentStack.emplace_back(eval);
constructAndDirectiveStack.emplace_back(&eval);
return true;
}
void exitConstructOrDirective() {
rewriteIfGotos();
auto *eval = constructAndDirectiveStack.back();
if (eval->isExecutableDirective()) {
// A construct at the end of an (unstructured) OpenACC or OpenMP
// construct region must have an exit target inside the region.
Fortran::lower::pft::EvaluationList &evaluationList =
*eval->evaluationList;
if (!evaluationList.empty() && evaluationList.back().isConstruct()) {
static const parser::ContinueStmt exitTarget{};
addEvaluation(
lower::pft::Evaluation{exitTarget, pftParentStack.back(), {}, {}});
}
}
popEvaluationList();
pftParentStack.pop_back();
constructAndDirectiveStack.pop_back();
}
/// Reset function state to that of an enclosing host function.
void resetFunctionState() {
if (!pftParentStack.empty()) {
pftParentStack.back().visit(common::visitors{
[&](lower::pft::FunctionLikeUnit &p) {
functionList = &p.nestedFunctions;
labelEvaluationMap = &p.labelEvaluationMap;
assignSymbolLabelMap = &p.assignSymbolLabelMap;
},
[&](lower::pft::ModuleLikeUnit &p) {
functionList = &p.nestedFunctions;
},
[&](auto &) { functionList = nullptr; },
});
}
}
template <typename A>
A &addUnit(A &&unit) {
pgm->getUnits().emplace_back(std::move(unit));
return std::get<A>(pgm->getUnits().back());
}
template <typename A>
A &addFunction(A &&func) {
if (functionList) {
functionList->emplace_back(std::move(func));
return functionList->back();
}
return addUnit(std::move(func));
}
// ActionStmt has a couple of non-conforming cases, explicitly handled here.
// The other cases use an Indirection, which are discarded in the PFT.
lower::pft::Evaluation
makeEvaluationAction(const parser::ActionStmt &statement,
parser::CharBlock position,
std::optional<parser::Label> label) {
return std::visit(
common::visitors{
[&](const auto &x) {
return lower::pft::Evaluation{
removeIndirection(x), pftParentStack.back(), position, label};
},
},
statement.u);
}
/// Append an Evaluation to the end of the current list.
lower::pft::Evaluation &addEvaluation(lower::pft::Evaluation &&eval) {
assert(functionList && "not in a function");
assert(!evaluationListStack.empty() && "empty evaluation list stack");
if (!constructAndDirectiveStack.empty())
eval.parentConstruct = constructAndDirectiveStack.back();
auto &entryPointList = eval.getOwningProcedure()->entryPointList;
evaluationListStack.back()->emplace_back(std::move(eval));
lower::pft::Evaluation *p = &evaluationListStack.back()->back();
if (p->isActionStmt() || p->isConstructStmt() || p->isEndStmt() ||
p->isExecutableDirective()) {
if (lastLexicalEvaluation) {
lastLexicalEvaluation->lexicalSuccessor = p;
p->printIndex = lastLexicalEvaluation->printIndex + 1;
} else {
p->printIndex = 1;
}
lastLexicalEvaluation = p;
for (std::size_t entryIndex = entryPointList.size() - 1;
entryIndex && !entryPointList[entryIndex].second->lexicalSuccessor;
--entryIndex)
// Link to the entry's first executable statement.
entryPointList[entryIndex].second->lexicalSuccessor = p;
} else if (const auto *entryStmt = p->getIf<parser::EntryStmt>()) {
const semantics::Symbol *sym =
std::get<parser::Name>(entryStmt->t).symbol;
assert(sym->has<semantics::SubprogramDetails>() &&
"entry must be a subprogram");
entryPointList.push_back(std::pair{sym, p});
}
if (p->label.has_value())
labelEvaluationMap->try_emplace(*p->label, p);
return evaluationListStack.back()->back();
}
/// push a new list on the stack of Evaluation lists
void pushEvaluationList(lower::pft::EvaluationList *evaluationList) {
assert(functionList && "not in a function");
assert(evaluationList && evaluationList->empty() &&
"evaluation list isn't correct");
evaluationListStack.emplace_back(evaluationList);
}
/// pop the current list and return to the last Evaluation list
void popEvaluationList() {
assert(functionList && "not in a function");
evaluationListStack.pop_back();
}
/// Rewrite IfConstructs containing a GotoStmt or CycleStmt to eliminate an
/// unstructured branch and a trivial basic block. The pre-branch-analysis
/// code:
///
/// <<IfConstruct>>
/// 1 If[Then]Stmt: if(cond) goto L
/// 2 GotoStmt: goto L
/// 3 EndIfStmt
/// <<End IfConstruct>>
/// 4 Statement: ...
/// 5 Statement: ...
/// 6 Statement: L ...
///
/// becomes:
///
/// <<IfConstruct>>
/// 1 If[Then]Stmt [negate]: if(cond) goto L
/// 4 Statement: ...
/// 5 Statement: ...
/// 3 EndIfStmt
/// <<End IfConstruct>>
/// 6 Statement: L ...
///
/// The If[Then]Stmt condition is implicitly negated. It is not modified
/// in the PFT. It must be negated when generating FIR. The GotoStmt or
/// CycleStmt is deleted.
///
/// The transformation is only valid for forward branch targets at the same
/// construct nesting level as the IfConstruct. The result must not violate
/// construct nesting requirements or contain an EntryStmt. The result
/// is subject to normal un/structured code classification analysis. The
/// result is allowed to violate the F18 Clause 11.1.2.1 prohibition on
/// transfer of control into the interior of a construct block, as that does
/// not compromise correct code generation. When two transformation
/// candidates overlap, at least one must be disallowed. In such cases,
/// the current heuristic favors simple code generation, which happens to
/// favor later candidates over earlier candidates. That choice is probably
/// not significant, but could be changed.
///
void rewriteIfGotos() {
auto &evaluationList = *evaluationListStack.back();
if (!evaluationList.size())
return;
struct T {
lower::pft::EvaluationList::iterator ifConstructIt;
parser::Label ifTargetLabel;
bool isCycleStmt = false;
};
llvm::SmallVector<T> ifCandidateStack;
const auto *doStmt =
evaluationList.begin()->getIf<parser::NonLabelDoStmt>();
std::string doName = doStmt ? getConstructName(*doStmt) : std::string{};
for (auto it = evaluationList.begin(), end = evaluationList.end();
it != end; ++it) {
auto &eval = *it;
if (eval.isA<parser::EntryStmt>()) {
ifCandidateStack.clear();
continue;
}
auto firstStmt = [](lower::pft::Evaluation *e) {
return e->isConstruct() ? &*e->evaluationList->begin() : e;
};
const Fortran::lower::pft::Evaluation &targetEval = *firstStmt(&eval);
bool targetEvalIsEndDoStmt = targetEval.isA<parser::EndDoStmt>();
auto branchTargetMatch = [&]() {
if (const parser::Label targetLabel =
ifCandidateStack.back().ifTargetLabel)
if (targetLabel == *targetEval.label)
return true; // goto target match
if (targetEvalIsEndDoStmt && ifCandidateStack.back().isCycleStmt)
return true; // cycle target match
return false;
};
if (targetEval.label || targetEvalIsEndDoStmt) {
while (!ifCandidateStack.empty() && branchTargetMatch()) {
lower::pft::EvaluationList::iterator ifConstructIt =
ifCandidateStack.back().ifConstructIt;
lower::pft::EvaluationList::iterator successorIt =
std::next(ifConstructIt);
if (successorIt != it) {
Fortran::lower::pft::EvaluationList &ifBodyList =
*ifConstructIt->evaluationList;
lower::pft::EvaluationList::iterator branchStmtIt =
std::next(ifBodyList.begin());
assert((branchStmtIt->isA<parser::GotoStmt>() ||
branchStmtIt->isA<parser::CycleStmt>()) &&
"expected goto or cycle statement");
ifBodyList.erase(branchStmtIt);
lower::pft::Evaluation &ifStmt = *ifBodyList.begin();
ifStmt.negateCondition = true;
ifStmt.lexicalSuccessor = firstStmt(&*successorIt);
lower::pft::EvaluationList::iterator endIfStmtIt =
std::prev(ifBodyList.end());
std::prev(it)->lexicalSuccessor = &*endIfStmtIt;
endIfStmtIt->lexicalSuccessor = firstStmt(&*it);
ifBodyList.splice(endIfStmtIt, evaluationList, successorIt, it);
for (; successorIt != endIfStmtIt; ++successorIt)
successorIt->parentConstruct = &*ifConstructIt;
}
ifCandidateStack.pop_back();
}
}
if (eval.isA<parser::IfConstruct>() && eval.evaluationList->size() == 3) {
const auto bodyEval = std::next(eval.evaluationList->begin());
if (const auto *gotoStmt = bodyEval->getIf<parser::GotoStmt>()) {
ifCandidateStack.push_back({it, gotoStmt->v});
} else if (doStmt) {
if (const auto *cycleStmt = bodyEval->getIf<parser::CycleStmt>()) {
std::string cycleName = getConstructName(*cycleStmt);
if (cycleName.empty() || cycleName == doName)
// This candidate will match doStmt's EndDoStmt.
ifCandidateStack.push_back({it, {}, true});
}
}
}
}
}
/// Mark IO statement ERR, EOR, and END specifier branch targets.
/// Mark an IO statement with an assigned format as unstructured.
template <typename A>
void analyzeIoBranches(lower::pft::Evaluation &eval, const A &stmt) {
auto analyzeFormatSpec = [&](const parser::Format &format) {
if (const auto *expr = std::get_if<parser::Expr>(&format.u)) {
if (semantics::ExprHasTypeCategory(*semantics::GetExpr(*expr),
common::TypeCategory::Integer))
eval.isUnstructured = true;
}
};
auto analyzeSpecs{[&](const auto &specList) {
for (const auto &spec : specList) {
std::visit(
Fortran::common::visitors{
[&](const Fortran::parser::Format &format) {
analyzeFormatSpec(format);
},
[&](const auto &label) {
using LabelNodes =
std::tuple<parser::ErrLabel, parser::EorLabel,
parser::EndLabel>;
if constexpr (common::HasMember<decltype(label), LabelNodes>)
markBranchTarget(eval, label.v);
}},
spec.u);
}
}};
using OtherIOStmts =
std::tuple<parser::BackspaceStmt, parser::CloseStmt,
parser::EndfileStmt, parser::FlushStmt, parser::OpenStmt,
parser::RewindStmt, parser::WaitStmt>;
if constexpr (std::is_same_v<A, parser::ReadStmt> ||
std::is_same_v<A, parser::WriteStmt>) {
if (stmt.format)
analyzeFormatSpec(*stmt.format);
analyzeSpecs(stmt.controls);
} else if constexpr (std::is_same_v<A, parser::PrintStmt>) {
analyzeFormatSpec(std::get<parser::Format>(stmt.t));
} else if constexpr (std::is_same_v<A, parser::InquireStmt>) {
if (const auto *specList =
std::get_if<std::list<parser::InquireSpec>>(&stmt.u))
analyzeSpecs(*specList);
} else if constexpr (common::HasMember<A, OtherIOStmts>) {
analyzeSpecs(stmt.v);
} else {
// Always crash if this is instantiated
static_assert(!std::is_same_v<A, parser::ReadStmt>,
"Unexpected IO statement");
}
}
/// Set the exit of a construct, possibly from multiple enclosing constructs.
void setConstructExit(lower::pft::Evaluation &eval) {
eval.constructExit = &eval.evaluationList->back().nonNopSuccessor();
}
/// Mark the target of a branch as a new block.
void markBranchTarget(lower::pft::Evaluation &sourceEvaluation,
lower::pft::Evaluation &targetEvaluation) {
sourceEvaluation.isUnstructured = true;
if (!sourceEvaluation.controlSuccessor)
sourceEvaluation.controlSuccessor = &targetEvaluation;
targetEvaluation.isNewBlock = true;
// If this is a branch into the body of a construct (usually illegal,
// but allowed in some legacy cases), then the targetEvaluation and its
// ancestors must be marked as unstructured.
lower::pft::Evaluation *sourceConstruct = sourceEvaluation.parentConstruct;
lower::pft::Evaluation *targetConstruct = targetEvaluation.parentConstruct;
if (targetConstruct &&
&targetConstruct->getFirstNestedEvaluation() == &targetEvaluation)
// A branch to an initial constructStmt is a branch to the construct.
targetConstruct = targetConstruct->parentConstruct;
if (targetConstruct) {
while (sourceConstruct && sourceConstruct != targetConstruct)
sourceConstruct = sourceConstruct->parentConstruct;
if (sourceConstruct != targetConstruct) // branch into a construct body
for (lower::pft::Evaluation *eval = &targetEvaluation; eval;
eval = eval->parentConstruct) {
eval->isUnstructured = true;
// If the branch is a backward branch into an already analyzed
// DO or IF construct, mark the construct exit as a new block.
// For a forward branch, the isUnstructured flag will cause this
// to be done when the construct is analyzed.
if (eval->constructExit && (eval->isA<parser::DoConstruct>() ||
eval->isA<parser::IfConstruct>()))
eval->constructExit->isNewBlock = true;
}
}
}
void markBranchTarget(lower::pft::Evaluation &sourceEvaluation,
parser::Label label) {
assert(label && "missing branch target label");
lower::pft::Evaluation *targetEvaluation{
labelEvaluationMap->find(label)->second};
assert(targetEvaluation && "missing branch target evaluation");
markBranchTarget(sourceEvaluation, *targetEvaluation);
}
/// Mark the successor of an Evaluation as a new block.
void markSuccessorAsNewBlock(lower::pft::Evaluation &eval) {
eval.nonNopSuccessor().isNewBlock = true;
}
template <typename A>
inline std::string getConstructName(const A &stmt) {
using MaybeConstructNameWrapper =
std::tuple<parser::BlockStmt, parser::CycleStmt, parser::ElseStmt,
parser::ElsewhereStmt, parser::EndAssociateStmt,
parser::EndBlockStmt, parser::EndCriticalStmt,
parser::EndDoStmt, parser::EndForallStmt, parser::EndIfStmt,
parser::EndSelectStmt, parser::EndWhereStmt,
parser::ExitStmt>;
if constexpr (common::HasMember<A, MaybeConstructNameWrapper>) {
if (stmt.v)
return stmt.v->ToString();
}
using MaybeConstructNameInTuple = std::tuple<
parser::AssociateStmt, parser::CaseStmt, parser::ChangeTeamStmt,
parser::CriticalStmt, parser::ElseIfStmt, parser::EndChangeTeamStmt,
parser::ForallConstructStmt, parser::IfThenStmt, parser::LabelDoStmt,
parser::MaskedElsewhereStmt, parser::NonLabelDoStmt,
parser::SelectCaseStmt, parser::SelectRankCaseStmt,
parser::TypeGuardStmt, parser::WhereConstructStmt>;
if constexpr (common::HasMember<A, MaybeConstructNameInTuple>) {
if (auto name = std::get<std::optional<parser::Name>>(stmt.t))
return name->ToString();
}
// These statements have multiple std::optional<parser::Name> elements.
if constexpr (std::is_same_v<A, parser::SelectRankStmt> ||
std::is_same_v<A, parser::SelectTypeStmt>) {
if (auto name = std::get<0>(stmt.t))
return name->ToString();
}
return {};
}
/// \p parentConstruct can be null if this statement is at the highest
/// level of a program.
template <typename A>
void insertConstructName(const A &stmt,
lower::pft::Evaluation *parentConstruct) {
std::string name = getConstructName(stmt);
if (!name.empty())
constructNameMap[name] = parentConstruct;
}
/// Insert branch links for a list of Evaluations.
/// \p parentConstruct can be null if the evaluationList contains the
/// top-level statements of a program.
void analyzeBranches(lower::pft::Evaluation *parentConstruct,
std::list<lower::pft::Evaluation> &evaluationList) {
lower::pft::Evaluation *lastConstructStmtEvaluation{};
for (auto &eval : evaluationList) {
eval.visit(common::visitors{
// Action statements (except IO statements)
[&](const parser::CallStmt &s) {
// Look for alternate return specifiers.
const auto &args =
std::get<std::list<parser::ActualArgSpec>>(s.v.t);
for (const auto &arg : args) {
const auto &actual = std::get<parser::ActualArg>(arg.t);
if (const auto *altReturn =
std::get_if<parser::AltReturnSpec>(&actual.u))
markBranchTarget(eval, altReturn->v);
}
},
[&](const parser::CycleStmt &s) {
std::string name = getConstructName(s);
lower::pft::Evaluation *construct{name.empty()
? doConstructStack.back()
: constructNameMap[name]};
assert(construct && "missing CYCLE construct");
markBranchTarget(eval, construct->evaluationList->back());
},
[&](const parser::ExitStmt &s) {
std::string name = getConstructName(s);
lower::pft::Evaluation *construct{name.empty()
? doConstructStack.back()
: constructNameMap[name]};
assert(construct && "missing EXIT construct");
markBranchTarget(eval, *construct->constructExit);
},
[&](const parser::GotoStmt &s) { markBranchTarget(eval, s.v); },
[&](const parser::IfStmt &) {
eval.lexicalSuccessor->isNewBlock = true;
lastConstructStmtEvaluation = &eval;
},
[&](const parser::ReturnStmt &) {
eval.isUnstructured = true;
if (eval.lexicalSuccessor->lexicalSuccessor)
markSuccessorAsNewBlock(eval);
},
[&](const parser::StopStmt &) {
eval.isUnstructured = true;
if (eval.lexicalSuccessor->lexicalSuccessor)
markSuccessorAsNewBlock(eval);
},
[&](const parser::ComputedGotoStmt &s) {
for (auto &label : std::get<std::list<parser::Label>>(s.t))
markBranchTarget(eval, label);
},
[&](const parser::ArithmeticIfStmt &s) {
markBranchTarget(eval, std::get<1>(s.t));
markBranchTarget(eval, std::get<2>(s.t));
markBranchTarget(eval, std::get<3>(s.t));
},
[&](const parser::AssignStmt &s) { // legacy label assignment
auto &label = std::get<parser::Label>(s.t);
const auto *sym = std::get<parser::Name>(s.t).symbol;
assert(sym && "missing AssignStmt symbol");
lower::pft::Evaluation *target{
labelEvaluationMap->find(label)->second};
assert(target && "missing branch target evaluation");
if (!target->isA<parser::FormatStmt>())
target->isNewBlock = true;
auto iter = assignSymbolLabelMap->find(*sym);
if (iter == assignSymbolLabelMap->end()) {
lower::pft::LabelSet labelSet{};
labelSet.insert(label);
assignSymbolLabelMap->try_emplace(*sym, labelSet);
} else {
iter->second.insert(label);
}
},
[&](const parser::AssignedGotoStmt &) {
// Although this statement is a branch, it doesn't have any
// explicit control successors. So the code at the end of the
// loop won't mark the successor. Do that here.
eval.isUnstructured = true;
markSuccessorAsNewBlock(eval);
},
// The first executable statement after an EntryStmt is a new block.
[&](const parser::EntryStmt &) {
eval.lexicalSuccessor->isNewBlock = true;
},
// Construct statements
[&](const parser::AssociateStmt &s) {
insertConstructName(s, parentConstruct);
},
[&](const parser::BlockStmt &s) {
insertConstructName(s, parentConstruct);
},
[&](const parser::SelectCaseStmt &s) {
insertConstructName(s, parentConstruct);
lastConstructStmtEvaluation = &eval;
},
[&](const parser::CaseStmt &) {
eval.isNewBlock = true;
lastConstructStmtEvaluation->controlSuccessor = &eval;
lastConstructStmtEvaluation = &eval;
},
[&](const parser::EndSelectStmt &) {
eval.nonNopSuccessor().isNewBlock = true;
lastConstructStmtEvaluation = nullptr;
},
[&](const parser::ChangeTeamStmt &s) {
insertConstructName(s, parentConstruct);
},
[&](const parser::CriticalStmt &s) {
insertConstructName(s, parentConstruct);
},
[&](const parser::NonLabelDoStmt &s) {
insertConstructName(s, parentConstruct);
doConstructStack.push_back(parentConstruct);
const auto &loopControl =
std::get<std::optional<parser::LoopControl>>(s.t);
if (!loopControl.has_value()) {
eval.isUnstructured = true; // infinite loop
return;
}
eval.nonNopSuccessor().isNewBlock = true;
eval.controlSuccessor = &evaluationList.back();
if (const auto *bounds =
std::get_if<parser::LoopControl::Bounds>(&loopControl->u)) {
if (bounds->name.thing.symbol->GetType()->IsNumeric(
common::TypeCategory::Real))
eval.isUnstructured = true; // real-valued loop control
} else if (std::get_if<parser::ScalarLogicalExpr>(
&loopControl->u)) {
eval.isUnstructured = true; // while loop
}
},
[&](const parser::EndDoStmt &) {
lower::pft::Evaluation &doEval = evaluationList.front();
eval.controlSuccessor = &doEval;
doConstructStack.pop_back();
if (parentConstruct->lowerAsStructured())
return;
// The loop is unstructured, which wasn't known for all cases when
// visiting the NonLabelDoStmt.
parentConstruct->constructExit->isNewBlock = true;
const auto &doStmt = *doEval.getIf<parser::NonLabelDoStmt>();
const auto &loopControl =
std::get<std::optional<parser::LoopControl>>(doStmt.t);
if (!loopControl.has_value())
return; // infinite loop
if (const auto *concurrent =
std::get_if<parser::LoopControl::Concurrent>(
&loopControl->u)) {
// If there is a mask, the EndDoStmt starts a new block.
const auto &header =
std::get<parser::ConcurrentHeader>(concurrent->t);
eval.isNewBlock |=
std::get<std::optional<parser::ScalarLogicalExpr>>(header.t)
.has_value();
}
},
[&](const parser::IfThenStmt &s) {
insertConstructName(s, parentConstruct);
eval.lexicalSuccessor->isNewBlock = true;
lastConstructStmtEvaluation = &eval;
},
[&](const parser::ElseIfStmt &) {
eval.isNewBlock = true;
eval.lexicalSuccessor->isNewBlock = true;
lastConstructStmtEvaluation->controlSuccessor = &eval;
lastConstructStmtEvaluation = &eval;
},
[&](const parser::ElseStmt &) {
eval.isNewBlock = true;
lastConstructStmtEvaluation->controlSuccessor = &eval;
lastConstructStmtEvaluation = nullptr;
},
[&](const parser::EndIfStmt &) {
if (parentConstruct->lowerAsUnstructured())
parentConstruct->constructExit->isNewBlock = true;
if (lastConstructStmtEvaluation) {
lastConstructStmtEvaluation->controlSuccessor =
parentConstruct->constructExit;
lastConstructStmtEvaluation = nullptr;
}
},
[&](const parser::SelectRankStmt &s) {
insertConstructName(s, parentConstruct);
},
[&](const parser::SelectRankCaseStmt &) { eval.isNewBlock = true; },
[&](const parser::SelectTypeStmt &s) {
insertConstructName(s, parentConstruct);
},
[&](const parser::TypeGuardStmt &) { eval.isNewBlock = true; },
// Constructs - set (unstructured) construct exit targets
[&](const parser::AssociateConstruct &) { setConstructExit(eval); },
[&](const parser::BlockConstruct &) {
// EndBlockStmt may have code.
eval.constructExit = &eval.evaluationList->back();
},
[&](const parser::CaseConstruct &) {
setConstructExit(eval);
eval.isUnstructured = true;
},
[&](const parser::ChangeTeamConstruct &) {
// EndChangeTeamStmt may have code.
eval.constructExit = &eval.evaluationList->back();
},
[&](const parser::CriticalConstruct &) {
// EndCriticalStmt may have code.
eval.constructExit = &eval.evaluationList->back();
},
[&](const parser::DoConstruct &) { setConstructExit(eval); },
[&](const parser::IfConstruct &) { setConstructExit(eval); },
[&](const parser::SelectRankConstruct &) {
setConstructExit(eval);
eval.isUnstructured = true;
},
[&](const parser::SelectTypeConstruct &) {
setConstructExit(eval);
eval.isUnstructured = true;
},
// Default - Common analysis for IO statements; otherwise nop.
[&](const auto &stmt) {
using A = std::decay_t<decltype(stmt)>;
using IoStmts = std::tuple<
parser::BackspaceStmt, parser::CloseStmt, parser::EndfileStmt,
parser::FlushStmt, parser::InquireStmt, parser::OpenStmt,
parser::PrintStmt, parser::ReadStmt, parser::RewindStmt,
parser::WaitStmt, parser::WriteStmt>;
if constexpr (common::HasMember<A, IoStmts>)
analyzeIoBranches(eval, stmt);
},
});
// Analyze construct evaluations.
if (eval.evaluationList)
analyzeBranches(&eval, *eval.evaluationList);
// Set the successor of the last statement in an IF or SELECT block.
if (!eval.controlSuccessor && eval.lexicalSuccessor &&
eval.lexicalSuccessor->isIntermediateConstructStmt()) {
eval.controlSuccessor = parentConstruct->constructExit;
eval.lexicalSuccessor->isNewBlock = true;
}
// Propagate isUnstructured flag to enclosing construct.
if (parentConstruct && eval.isUnstructured)
parentConstruct->isUnstructured = true;
// The successor of a branch starts a new block.
if (eval.controlSuccessor && eval.isActionStmt() &&
eval.lowerAsUnstructured())
markSuccessorAsNewBlock(eval);
}
}
/// For multiple entry subprograms, build a list of the dummy arguments that
/// appear in some, but not all entry points. For those that are functions,
/// also find one of the largest function results, since a single result
/// container holds the result for all entries.
void processEntryPoints() {
lower::pft::Evaluation *initialEval = &evaluationListStack.back()->front();
lower::pft::FunctionLikeUnit *unit = initialEval->getOwningProcedure();
int entryCount = unit->entryPointList.size();
if (entryCount == 1)
return;
llvm::DenseMap<semantics::Symbol *, int> dummyCountMap;
for (int entryIndex = 0; entryIndex < entryCount; ++entryIndex) {
unit->setActiveEntry(entryIndex);
const auto &details =
unit->getSubprogramSymbol().get<semantics::SubprogramDetails>();
for (semantics::Symbol *arg : details.dummyArgs()) {
if (!arg)
continue; // alternate return specifier (no actual argument)
const auto iter = dummyCountMap.find(arg);
if (iter == dummyCountMap.end())
dummyCountMap.try_emplace(arg, 1);
else
++iter->second;
}
if (details.isFunction()) {
const semantics::Symbol *resultSym = &details.result();
assert(resultSym && "missing result symbol");
if (!unit->primaryResult ||
unit->primaryResult->size() < resultSym->size())
unit->primaryResult = resultSym;
}
}
unit->setActiveEntry(0);
for (auto arg : dummyCountMap)
if (arg.second < entryCount)
unit->nonUniversalDummyArguments.push_back(arg.first);
// The first executable statement in the subprogram is preceded by a
// branch to the entry point, so it starts a new block.
if (initialEval->hasNestedEvaluations())
initialEval = &initialEval->getFirstNestedEvaluation();
else if (initialEval->isA<Fortran::parser::EntryStmt>())
initialEval = initialEval->lexicalSuccessor;
initialEval->isNewBlock = true;
}
std::unique_ptr<lower::pft::Program> pgm;
std::vector<lower::pft::PftNode> pftParentStack;
const semantics::SemanticsContext &semanticsContext;
/// functionList points to the internal or module procedure function list
/// of a FunctionLikeUnit or a ModuleLikeUnit. It may be null.
std::list<lower::pft::FunctionLikeUnit> *functionList{};
std::vector<lower::pft::Evaluation *> constructAndDirectiveStack{};
std::vector<lower::pft::Evaluation *> doConstructStack{};
/// evaluationListStack is the current nested construct evaluationList state.
std::vector<lower::pft::EvaluationList *> evaluationListStack{};
llvm::DenseMap<parser::Label, lower::pft::Evaluation *> *labelEvaluationMap{};
lower::pft::SymbolLabelMap *assignSymbolLabelMap{};
std::map<std::string, lower::pft::Evaluation *> constructNameMap{};
lower::pft::Evaluation *lastLexicalEvaluation{};
};
class PFTDumper {
public:
void dumpPFT(llvm::raw_ostream &outputStream,
const lower::pft::Program &pft) {
for (auto &unit : pft.getUnits()) {
std::visit(common::visitors{
[&](const lower::pft::BlockDataUnit &unit) {
outputStream << getNodeIndex(unit) << " ";
outputStream << "BlockData: ";
outputStream << "\nEnd BlockData\n\n";
},
[&](const lower::pft::FunctionLikeUnit &func) {
dumpFunctionLikeUnit(outputStream, func);
},
[&](const lower::pft::ModuleLikeUnit &unit) {
dumpModuleLikeUnit(outputStream, unit);
},
[&](const lower::pft::CompilerDirectiveUnit &unit) {
dumpCompilerDirectiveUnit(outputStream, unit);
},
},
unit);
}
}
llvm::StringRef evaluationName(const lower::pft::Evaluation &eval) {
return eval.visit([](const auto &parseTreeNode) {
return parser::ParseTreeDumper::GetNodeName(parseTreeNode);
});
}
void dumpEvaluation(llvm::raw_ostream &outputStream,
const lower::pft::Evaluation &eval,
const std::string &indentString, int indent = 1) {
llvm::StringRef name = evaluationName(eval);
llvm::StringRef newBlock = eval.isNewBlock ? "^" : "";
llvm::StringRef bang = eval.isUnstructured ? "!" : "";
outputStream << indentString;
if (eval.printIndex)
outputStream << eval.printIndex << ' ';
if (eval.hasNestedEvaluations())
outputStream << "<<" << newBlock << name << bang << ">>";
else
outputStream << newBlock << name << bang;
if (eval.negateCondition)
outputStream << " [negate]";
if (eval.constructExit)
outputStream << " -> " << eval.constructExit->printIndex;
else if (eval.controlSuccessor)
outputStream << " -> " << eval.controlSuccessor->printIndex;
else if (eval.isA<parser::EntryStmt>() && eval.lexicalSuccessor)
outputStream << " -> " << eval.lexicalSuccessor->printIndex;
if (!eval.position.empty())
outputStream << ": " << eval.position.ToString();
else if (auto *dir = eval.getIf<Fortran::parser::CompilerDirective>())
outputStream << ": !" << dir->source.ToString();
outputStream << '\n';
if (eval.hasNestedEvaluations()) {
dumpEvaluationList(outputStream, *eval.evaluationList, indent + 1);
outputStream << indentString << "<<End " << name << bang << ">>\n";
}
}
void dumpEvaluation(llvm::raw_ostream &ostream,
const lower::pft::Evaluation &eval) {
dumpEvaluation(ostream, eval, "");
}
void dumpEvaluationList(llvm::raw_ostream &outputStream,
const lower::pft::EvaluationList &evaluationList,
int indent = 1) {
static const auto white = " ++"s;
auto indentString = white.substr(0, indent * 2);
for (const lower::pft::Evaluation &eval : evaluationList)
dumpEvaluation(outputStream, eval, indentString, indent);
}
void
dumpFunctionLikeUnit(llvm::raw_ostream &outputStream,
const lower::pft::FunctionLikeUnit &functionLikeUnit) {
outputStream << getNodeIndex(functionLikeUnit) << " ";
llvm::StringRef unitKind;
llvm::StringRef name;
llvm::StringRef header;
if (functionLikeUnit.beginStmt) {
functionLikeUnit.beginStmt->visit(common::visitors{
[&](const parser::Statement<parser::ProgramStmt> &stmt) {
unitKind = "Program";
name = toStringRef(stmt.statement.v.source);
},
[&](const parser::Statement<parser::FunctionStmt> &stmt) {
unitKind = "Function";
name = toStringRef(std::get<parser::Name>(stmt.statement.t).source);
header = toStringRef(stmt.source);
},
[&](const parser::Statement<parser::SubroutineStmt> &stmt) {
unitKind = "Subroutine";
name = toStringRef(std::get<parser::Name>(stmt.statement.t).source);
header = toStringRef(stmt.source);
},
[&](const parser::Statement<parser::MpSubprogramStmt> &stmt) {
unitKind = "MpSubprogram";
name = toStringRef(stmt.statement.v.source);
header = toStringRef(stmt.source);
},
[&](const auto &) { llvm_unreachable("not a valid begin stmt"); },
});
} else {
unitKind = "Program";
name = "<anonymous>";
}
outputStream << unitKind << ' ' << name;
if (!header.empty())
outputStream << ": " << header;
outputStream << '\n';
dumpEvaluationList(outputStream, functionLikeUnit.evaluationList);
if (!functionLikeUnit.nestedFunctions.empty()) {
outputStream << "\nContains\n";
for (const lower::pft::FunctionLikeUnit &func :
functionLikeUnit.nestedFunctions)
dumpFunctionLikeUnit(outputStream, func);
outputStream << "End Contains\n";
}
outputStream << "End " << unitKind << ' ' << name << "\n\n";
}
void dumpModuleLikeUnit(llvm::raw_ostream &outputStream,
const lower::pft::ModuleLikeUnit &moduleLikeUnit) {
outputStream << getNodeIndex(moduleLikeUnit) << " ";
outputStream << "ModuleLike:\n";
dumpEvaluationList(outputStream, moduleLikeUnit.evaluationList);
outputStream << "Contains\n";
for (const lower::pft::FunctionLikeUnit &func :
moduleLikeUnit.nestedFunctions)
dumpFunctionLikeUnit(outputStream, func);
outputStream << "End Contains\nEnd ModuleLike\n\n";
}
// Top level directives
void dumpCompilerDirectiveUnit(
llvm::raw_ostream &outputStream,
const lower::pft::CompilerDirectiveUnit &directive) {
outputStream << getNodeIndex(directive) << " ";
outputStream << "CompilerDirective: !";
outputStream << directive.get<Fortran::parser::CompilerDirective>()
.source.ToString();
outputStream << "\nEnd CompilerDirective\n\n";
}
template <typename T>
std::size_t getNodeIndex(const T &node) {
auto addr = static_cast<const void *>(&node);
auto it = nodeIndexes.find(addr);
if (it != nodeIndexes.end())
return it->second;
nodeIndexes.try_emplace(addr, nextIndex);
return nextIndex++;
}
std::size_t getNodeIndex(const lower::pft::Program &) { return 0; }
private:
llvm::DenseMap<const void *, std::size_t> nodeIndexes;
std::size_t nextIndex{1}; // 0 is the root
};
} // namespace
template <typename A, typename T>
static lower::pft::FunctionLikeUnit::FunctionStatement
getFunctionStmt(const T &func) {
lower::pft::FunctionLikeUnit::FunctionStatement result{
std::get<parser::Statement<A>>(func.t)};
return result;
}
template <typename A, typename T>
static lower::pft::ModuleLikeUnit::ModuleStatement getModuleStmt(const T &mod) {
lower::pft::ModuleLikeUnit::ModuleStatement result{
std::get<parser::Statement<A>>(mod.t)};
return result;
}
template <typename A>
static const semantics::Symbol *getSymbol(A &beginStmt) {
const auto *symbol = beginStmt.visit(common::visitors{
[](const parser::Statement<parser::ProgramStmt> &stmt)
-> const semantics::Symbol * { return stmt.statement.v.symbol; },
[](const parser::Statement<parser::FunctionStmt> &stmt)
-> const semantics::Symbol * {
return std::get<parser::Name>(stmt.statement.t).symbol;
},
[](const parser::Statement<parser::SubroutineStmt> &stmt)
-> const semantics::Symbol * {
return std::get<parser::Name>(stmt.statement.t).symbol;
},
[](const parser::Statement<parser::MpSubprogramStmt> &stmt)
-> const semantics::Symbol * { return stmt.statement.v.symbol; },
[](const parser::Statement<parser::ModuleStmt> &stmt)
-> const semantics::Symbol * { return stmt.statement.v.symbol; },
[](const parser::Statement<parser::SubmoduleStmt> &stmt)
-> const semantics::Symbol * {
return std::get<parser::Name>(stmt.statement.t).symbol;
},
[](const auto &) -> const semantics::Symbol * {
llvm_unreachable("unknown FunctionLike or ModuleLike beginStmt");
return nullptr;
}});
assert(symbol && "parser::Name must have resolved symbol");
return symbol;
}
bool Fortran::lower::pft::Evaluation::lowerAsStructured() const {
return !lowerAsUnstructured();
}
bool Fortran::lower::pft::Evaluation::lowerAsUnstructured() const {
return isUnstructured || clDisableStructuredFir;
}
lower::pft::FunctionLikeUnit *
Fortran::lower::pft::Evaluation::getOwningProcedure() const {
return parent.visit(common::visitors{
[](lower::pft::FunctionLikeUnit &c) { return &c; },
[&](lower::pft::Evaluation &c) { return c.getOwningProcedure(); },
[](auto &) -> lower::pft::FunctionLikeUnit * { return nullptr; },
});
}
bool Fortran::lower::definedInCommonBlock(const semantics::Symbol &sym) {
return semantics::FindCommonBlockContaining(sym);
}
static bool isReEntrant(const Fortran::semantics::Scope &scope) {
if (scope.kind() == Fortran::semantics::Scope::Kind::MainProgram)
return false;
if (scope.kind() == Fortran::semantics::Scope::Kind::Subprogram) {
const Fortran::semantics::Symbol *sym = scope.symbol();
assert(sym && "Subprogram scope must have a symbol");
return sym->attrs().test(semantics::Attr::RECURSIVE) ||
(!sym->attrs().test(semantics::Attr::NON_RECURSIVE) &&
Fortran::lower::defaultRecursiveFunctionSetting());
}
if (scope.kind() == Fortran::semantics::Scope::Kind::Module)
return false;
return true;
}
/// Is the symbol `sym` a global?
bool Fortran::lower::symbolIsGlobal(const semantics::Symbol &sym) {
if (const auto *details = sym.detailsIf<semantics::ObjectEntityDetails>()) {
if (details->init())
return true;
if (!isReEntrant(sym.owner())) {
// Turn array and character of non re-entrant programs (like the main
// program) into global memory.
if (const Fortran::semantics::DeclTypeSpec *symTy = sym.GetType())
if (symTy->category() == semantics::DeclTypeSpec::Character)
if (auto e = symTy->characterTypeSpec().length().GetExplicit())
return true;
if (!details->shape().empty() || !details->coshape().empty())
return true;
}
}
return semantics::IsSaved(sym) || lower::definedInCommonBlock(sym) ||
semantics::IsNamedConstant(sym);
}
namespace {
/// This helper class is for sorting the symbols in the symbol table. We want
/// the symbols in an order such that a symbol will be visited after those it
/// depends upon. Otherwise this sort is stable and preserves the order of the
/// symbol table, which is sorted by name.
struct SymbolDependenceDepth {
explicit SymbolDependenceDepth(
std::vector<std::vector<lower::pft::Variable>> &vars)
: vars{vars} {}
void analyzeAliasesInCurrentScope(const semantics::Scope &scope) {
// FIXME: When this function is called on the scope of an internal
// procedure whose parent contains an EQUIVALENCE set and the internal
// procedure uses variables from that EQUIVALENCE set, we end up creating
// an AggregateStore for those variables unnecessarily.
//
/// If this is a function nested in a module no host associated
/// symbol are added to the function scope for module symbols used in this
/// scope. As a result, alias analysis in parent module scopes must be
/// preformed here.
const semantics::Scope *parentScope = &scope;
while (!parentScope->IsGlobal()) {
parentScope = &parentScope->parent();
if (parentScope->IsModule())
analyzeAliases(*parentScope);
}
for (const auto &iter : scope) {
const semantics::Symbol &ultimate = iter.second.get().GetUltimate();
if (skipSymbol(ultimate))
continue;
analyzeAliases(ultimate.owner());
}
// add all aggregate stores to the front of the work list
adjustSize(1);
// The copy in the loop matters, 'stores' will still be used.
for (auto st : stores)
vars[0].emplace_back(std::move(st));
}
// Compute the offset of the last byte that resides in the symbol.
inline static std::size_t offsetWidth(const Fortran::semantics::Symbol &sym) {
std::size_t width = sym.offset();
if (std::size_t size = sym.size())
width += size - 1;
return width;
}
// Analyze the equivalence sets. This analysis need not be performed when the
// scope has no equivalence sets.
void analyzeAliases(const semantics::Scope &scope) {
if (scope.equivalenceSets().empty())
return;
// Don't analyze a scope if it has already been analyzed.
if (analyzedScopes.find(&scope) != analyzedScopes.end())
return;
analyzedScopes.insert(&scope);
std::list<std::list<semantics::SymbolRef>> aggregates =
Fortran::semantics::GetStorageAssociations(scope);
for (std::list<semantics::SymbolRef> aggregate : aggregates) {
const Fortran::semantics::Symbol *aggregateSym = nullptr;
bool isGlobal = false;
const semantics::Symbol &first = *aggregate.front();
std::size_t start = first.offset();
std::size_t end = first.offset() + first.size();
const Fortran::semantics::Symbol *namingSym = nullptr;
for (semantics::SymbolRef symRef : aggregate) {
const semantics::Symbol &sym = *symRef;
aliasSyms.insert(&sym);
if (sym.test(Fortran::semantics::Symbol::Flag::CompilerCreated)) {
aggregateSym = &sym;
} else {
isGlobal |= lower::symbolIsGlobal(sym);
start = std::min(sym.offset(), start);
end = std::max(sym.offset() + sym.size(), end);
if (!namingSym || (sym.name() < namingSym->name()))
namingSym = &sym;
}
}
assert(namingSym && "must contain at least one user symbol");
if (!aggregateSym) {
stores.emplace_back(
Fortran::lower::pft::Variable::Interval{start, end - start},
*namingSym, isGlobal);
} else {
stores.emplace_back(*aggregateSym, *namingSym, isGlobal);
}
}
}
// Recursively visit each symbol to determine the height of its dependence on
// other symbols.
int analyze(const semantics::Symbol &sym) {
auto done = seen.insert(&sym);
LLVM_DEBUG(llvm::dbgs() << "analyze symbol: " << sym << '\n');
if (!done.second)
return 0;
if (semantics::IsProcedure(sym)) {
// TODO: add declaration?
return 0;
}
semantics::Symbol ultimate = sym.GetUltimate();
if (const auto *details =
ultimate.detailsIf<semantics::NamelistDetails>()) {
// handle namelist group symbols
for (const semantics::SymbolRef &s : details->objects())
analyze(s);
return 0;
}
if (!ultimate.has<semantics::ObjectEntityDetails>() &&
!ultimate.has<semantics::ProcEntityDetails>())
return 0;
if (sym.has<semantics::DerivedTypeDetails>())
llvm_unreachable("not yet implemented - derived type analysis");
// Symbol must be something lowering will have to allocate.
int depth = 0;
const semantics::DeclTypeSpec *symTy = sym.GetType();
assert(symTy && "symbol must have a type");
// Analyze symbols appearing in object entity specification expression. This
// ensures these symbols will be instantiated before the current one.
// This is not done for object entities that are host associated because
// they must be instantiated from the value of the host symbols (the
// specification expressions should not be re-evaluated).
if (const auto *details = sym.detailsIf<semantics::ObjectEntityDetails>()) {
// check CHARACTER's length
if (symTy->category() == semantics::DeclTypeSpec::Character)
if (auto e = symTy->characterTypeSpec().length().GetExplicit())
for (const auto &s : evaluate::CollectSymbols(*e))
depth = std::max(analyze(s) + 1, depth);
auto doExplicit = [&](const auto &bound) {
if (bound.isExplicit()) {
semantics::SomeExpr e{*bound.GetExplicit()};
for (const auto &s : evaluate::CollectSymbols(e))
depth = std::max(analyze(s) + 1, depth);
}
};
// handle any symbols in array bound declarations
for (const semantics::ShapeSpec &subs : details->shape()) {
doExplicit(subs.lbound());
doExplicit(subs.ubound());
}
// handle any symbols in coarray bound declarations
for (const semantics::ShapeSpec &subs : details->coshape()) {
doExplicit(subs.lbound());
doExplicit(subs.ubound());
}
// handle any symbols in initialization expressions
if (auto e = details->init())
for (const auto &s : evaluate::CollectSymbols(*e))
depth = std::max(analyze(s) + 1, depth);
}
adjustSize(depth + 1);
bool global = lower::symbolIsGlobal(sym);
vars[depth].emplace_back(sym, global, depth);
if (semantics::IsAllocatable(sym))
vars[depth].back().setHeapAlloc();
if (semantics::IsPointer(sym))
vars[depth].back().setPointer();
if (ultimate.attrs().test(semantics::Attr::TARGET))
vars[depth].back().setTarget();
// If there are alias sets, then link the participating variables to their
// aggregate stores when constructing the new variable on the list.
if (lower::pft::Variable::AggregateStore *store = findStoreIfAlias(sym)) {
vars[depth].back().setAlias(store->getOffset());
}
return depth;
}
/// Save the final list of variable allocations as a single vector and free
/// the rest.
void finalize() {
for (int i = 1, end = vars.size(); i < end; ++i)
vars[0].insert(vars[0].end(), vars[i].begin(), vars[i].end());
vars.resize(1);
}
Fortran::lower::pft::Variable::AggregateStore *
findStoreIfAlias(const Fortran::evaluate::Symbol &sym) {
const semantics::Symbol &ultimate = sym.GetUltimate();
const semantics::Scope &scope = ultimate.owner();
// Expect the total number of EQUIVALENCE sets to be small for a typical
// Fortran program.
if (aliasSyms.find(&ultimate) != aliasSyms.end()) {
LLVM_DEBUG(llvm::dbgs() << "symbol: " << ultimate << '\n');
LLVM_DEBUG(llvm::dbgs() << "scope: " << scope << '\n');
std::size_t off = ultimate.offset();
std::size_t symSize = ultimate.size();
for (lower::pft::Variable::AggregateStore &v : stores) {
if (&v.getOwningScope() == &scope) {
auto intervalOff = std::get<0>(v.interval);
auto intervalSize = std::get<1>(v.interval);
if (off >= intervalOff && off < intervalOff + intervalSize)
return &v;
// Zero sized symbol in zero sized equivalence.
if (off == intervalOff && symSize == 0)
return &v;
}
}
// clang-format off
LLVM_DEBUG(
llvm::dbgs() << "looking for " << off << "\n{\n";
for (lower::pft::Variable::AggregateStore &v : stores) {
llvm::dbgs() << " in scope: " << &v.getOwningScope() << "\n";
llvm::dbgs() << " i = [" << std::get<0>(v.interval) << ".."
<< std::get<0>(v.interval) + std::get<1>(v.interval)
<< "]\n";
}
llvm::dbgs() << "}\n");
// clang-format on
llvm_unreachable("the store must be present");
}
return nullptr;
}
private:
/// Skip symbol in alias analysis.
bool skipSymbol(const semantics::Symbol &sym) {
// Common block equivalences are largely managed by the front end.
// Compiler generated symbols ('.' names) cannot be equivalenced.
// FIXME: Equivalence code generation may need to be revisited.
return !sym.has<semantics::ObjectEntityDetails>() ||
lower::definedInCommonBlock(sym) || sym.name()[0] == '.';
}
// Make sure the table is of appropriate size.
void adjustSize(std::size_t size) {
if (vars.size() < size)
vars.resize(size);
}
llvm::SmallSet<const semantics::Symbol *, 32> seen;
std::vector<std::vector<lower::pft::Variable>> &vars;
llvm::SmallSet<const semantics::Symbol *, 32> aliasSyms;
/// Set of Scope that have been analyzed for aliases.
llvm::SmallSet<const semantics::Scope *, 4> analyzedScopes;
std::vector<Fortran::lower::pft::Variable::AggregateStore> stores;
};
} // namespace
static void processSymbolTable(
const semantics::Scope &scope,
std::vector<std::vector<Fortran::lower::pft::Variable>> &varList) {
SymbolDependenceDepth sdd{varList};
sdd.analyzeAliasesInCurrentScope(scope);
for (const auto &iter : scope)
sdd.analyze(iter.second.get());
sdd.finalize();
}
//===----------------------------------------------------------------------===//
// FunctionLikeUnit implementation
//===----------------------------------------------------------------------===//
Fortran::lower::pft::FunctionLikeUnit::FunctionLikeUnit(
const parser::MainProgram &func, const lower::pft::PftNode &parent,
const semantics::SemanticsContext &semanticsContext)
: ProgramUnit{func, parent}, endStmt{
getFunctionStmt<parser::EndProgramStmt>(
func)} {
const auto &programStmt =
std::get<std::optional<parser::Statement<parser::ProgramStmt>>>(func.t);
if (programStmt.has_value()) {
beginStmt = FunctionStatement(programStmt.value());
const semantics::Symbol *symbol = getSymbol(*beginStmt);
entryPointList[0].first = symbol;
processSymbolTable(*symbol->scope(), varList);
} else {
processSymbolTable(
semanticsContext.FindScope(
std::get<parser::Statement<parser::EndProgramStmt>>(func.t).source),
varList);
}
}
Fortran::lower::pft::FunctionLikeUnit::FunctionLikeUnit(
const parser::FunctionSubprogram &func, const lower::pft::PftNode &parent,
const semantics::SemanticsContext &)
: ProgramUnit{func, parent},
beginStmt{getFunctionStmt<parser::FunctionStmt>(func)},
endStmt{getFunctionStmt<parser::EndFunctionStmt>(func)} {
const semantics::Symbol *symbol = getSymbol(*beginStmt);
entryPointList[0].first = symbol;
processSymbolTable(*symbol->scope(), varList);
}
Fortran::lower::pft::FunctionLikeUnit::FunctionLikeUnit(
const parser::SubroutineSubprogram &func, const lower::pft::PftNode &parent,
const semantics::SemanticsContext &)
: ProgramUnit{func, parent},
beginStmt{getFunctionStmt<parser::SubroutineStmt>(func)},
endStmt{getFunctionStmt<parser::EndSubroutineStmt>(func)} {
const semantics::Symbol *symbol = getSymbol(*beginStmt);
entryPointList[0].first = symbol;
processSymbolTable(*symbol->scope(), varList);
}
Fortran::lower::pft::FunctionLikeUnit::FunctionLikeUnit(
const parser::SeparateModuleSubprogram &func,
const lower::pft::PftNode &parent, const semantics::SemanticsContext &)
: ProgramUnit{func, parent},
beginStmt{getFunctionStmt<parser::MpSubprogramStmt>(func)},
endStmt{getFunctionStmt<parser::EndMpSubprogramStmt>(func)} {
const semantics::Symbol *symbol = getSymbol(*beginStmt);
entryPointList[0].first = symbol;
processSymbolTable(*symbol->scope(), varList);
}
Fortran::lower::HostAssociations &
Fortran::lower::pft::FunctionLikeUnit::parentHostAssoc() {
if (auto *par = parent.getIf<FunctionLikeUnit>())
return par->hostAssociations;
llvm::report_fatal_error("parent is not a function");
}
bool Fortran::lower::pft::FunctionLikeUnit::parentHasHostAssoc() {
if (auto *par = parent.getIf<FunctionLikeUnit>())
return !par->hostAssociations.empty();
return false;
}
parser::CharBlock
Fortran::lower::pft::FunctionLikeUnit::getStartingSourceLoc() const {
if (beginStmt)
return stmtSourceLoc(*beginStmt);
if (!evaluationList.empty())
return evaluationList.front().position;
return stmtSourceLoc(endStmt);
}
//===----------------------------------------------------------------------===//
// ModuleLikeUnit implementation
//===----------------------------------------------------------------------===//
Fortran::lower::pft::ModuleLikeUnit::ModuleLikeUnit(
const parser::Module &m, const lower::pft::PftNode &parent)
: ProgramUnit{m, parent}, beginStmt{getModuleStmt<parser::ModuleStmt>(m)},
endStmt{getModuleStmt<parser::EndModuleStmt>(m)} {
const semantics::Symbol *symbol = getSymbol(beginStmt);
processSymbolTable(*symbol->scope(), varList);
}
Fortran::lower::pft::ModuleLikeUnit::ModuleLikeUnit(
const parser::Submodule &m, const lower::pft::PftNode &parent)
: ProgramUnit{m, parent}, beginStmt{getModuleStmt<parser::SubmoduleStmt>(
m)},
endStmt{getModuleStmt<parser::EndSubmoduleStmt>(m)} {
const semantics::Symbol *symbol = getSymbol(beginStmt);
processSymbolTable(*symbol->scope(), varList);
}
parser::CharBlock
Fortran::lower::pft::ModuleLikeUnit::getStartingSourceLoc() const {
return stmtSourceLoc(beginStmt);
}
const Fortran::semantics::Scope &
Fortran::lower::pft::ModuleLikeUnit::getScope() const {
const Fortran::semantics::Symbol *symbol = getSymbol(beginStmt);
assert(symbol && symbol->scope() &&
"Module statement must have a symbol with a scope");
return *symbol->scope();
}
//===----------------------------------------------------------------------===//
// BlockDataUnit implementation
//===----------------------------------------------------------------------===//
Fortran::lower::pft::BlockDataUnit::BlockDataUnit(
const parser::BlockData &bd, const lower::pft::PftNode &parent,
const semantics::SemanticsContext &semanticsContext)
: ProgramUnit{bd, parent},
symTab{semanticsContext.FindScope(
std::get<parser::Statement<parser::EndBlockDataStmt>>(bd.t).source)} {
}
std::unique_ptr<lower::pft::Program>
Fortran::lower::createPFT(const parser::Program &root,
const semantics::SemanticsContext &semanticsContext) {
PFTBuilder walker(semanticsContext);
Walk(root, walker);
return walker.result();
}
// FIXME: FlangDriver
// This option should be integrated with the real driver as the default of
// RECURSIVE vs. NON_RECURSIVE may be changed by other command line options,
// etc., etc.
bool Fortran::lower::defaultRecursiveFunctionSetting() {
return !nonRecursiveProcedures;
}
void Fortran::lower::dumpPFT(llvm::raw_ostream &outputStream,
const lower::pft::Program &pft) {
PFTDumper{}.dumpPFT(outputStream, pft);
}
void Fortran::lower::pft::Program::dump() const {
dumpPFT(llvm::errs(), *this);
}
void Fortran::lower::pft::Evaluation::dump() const {
PFTDumper{}.dumpEvaluation(llvm::errs(), *this);
}
void Fortran::lower::pft::Variable::dump() const {
if (auto *s = std::get_if<Nominal>(&var)) {
llvm::errs() << "symbol: " << s->symbol->name();
llvm::errs() << " (depth: " << s->depth << ')';
if (s->global)
llvm::errs() << ", global";
if (s->heapAlloc)
llvm::errs() << ", allocatable";
if (s->pointer)
llvm::errs() << ", pointer";
if (s->target)
llvm::errs() << ", target";
if (s->aliaser)
llvm::errs() << ", equivalence(" << s->aliasOffset << ')';
} else if (auto *s = std::get_if<AggregateStore>(&var)) {
llvm::errs() << "interval[" << std::get<0>(s->interval) << ", "
<< std::get<1>(s->interval) << "]:";
llvm::errs() << " name: " << toStringRef(s->getNamingSymbol().name());
if (s->isGlobal())
llvm::errs() << ", global";
if (s->initialValueSymbol)
llvm::errs() << ", initial value: {" << *s->initialValueSymbol << "}";
} else {
llvm_unreachable("not a Variable");
}
llvm::errs() << '\n';
}
void Fortran::lower::pft::FunctionLikeUnit::dump() const {
PFTDumper{}.dumpFunctionLikeUnit(llvm::errs(), *this);
}
void Fortran::lower::pft::ModuleLikeUnit::dump() const {
PFTDumper{}.dumpModuleLikeUnit(llvm::errs(), *this);
}
/// The BlockDataUnit dump is just the associated symbol table.
void Fortran::lower::pft::BlockDataUnit::dump() const {
llvm::errs() << "block data {\n" << symTab << "\n}\n";
}
std::vector<Fortran::lower::pft::Variable>
Fortran::lower::pft::buildFuncResultDependencyList(
const Fortran::semantics::Symbol &symbol) {
std::vector<std::vector<pft::Variable>> variableList;
SymbolDependenceDepth sdd(variableList);
sdd.analyzeAliasesInCurrentScope(symbol.owner());
sdd.analyze(symbol);
sdd.finalize();
// Remove the pft::variable for the result itself, only its dependencies
// should be returned in the list.
assert(!variableList[0].empty() && "must at least contain the result");
assert(&variableList[0].back().getSymbol() == &symbol &&
"result sym should be last");
variableList[0].pop_back();
return variableList[0];
}
namespace {
/// Helper class to find all the symbols referenced in a FunctionLikeUnit.
/// It defines a parse tree visitor doing a deep visit in all nodes with
/// symbols (including evaluate::Expr).
struct SymbolVisitor {
template <typename A>
bool Pre(const A &x) {
if constexpr (Fortran::parser::HasTypedExpr<A>::value)
if (const auto *expr = Fortran::semantics::GetExpr(x))
visitExpr(*expr);
return true;
}
bool Pre(const Fortran::parser::Name &name) {
if (const semantics::Symbol *symbol = name.symbol)
visitSymbol(*symbol);
return false;
}
void visitExpr(const Fortran::lower::SomeExpr &expr) {
for (const semantics::Symbol &symbol :
Fortran::evaluate::CollectSymbols(expr))
visitSymbol(symbol);
}
void visitSymbol(const Fortran::semantics::Symbol &symbol) {
callBack(symbol);
// Visit statement function body since it will be inlined in lowering.
if (const auto *subprogramDetails =
symbol.detailsIf<Fortran::semantics::SubprogramDetails>())
if (const auto &maybeExpr = subprogramDetails->stmtFunction())
visitExpr(*maybeExpr);
}
template <typename A>
constexpr void Post(const A &) {}
const std::function<void(const Fortran::semantics::Symbol &)> &callBack;
};
} // namespace
void Fortran::lower::pft::visitAllSymbols(
const Fortran::lower::pft::FunctionLikeUnit &funit,
const std::function<void(const Fortran::semantics::Symbol &)> callBack) {
SymbolVisitor visitor{callBack};
funit.visit([&](const auto &functionParserNode) {
parser::Walk(functionParserNode, visitor);
});
}
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