source: src/Concurrency/Waitfor.cpp @ 62a38e7

//
// Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// Waitfor.cpp -- Expand waitfor clauses into code.
//
// Author           : Andrew Beach
// Created On       : Fri May 27 10:31:00 2022
// Last Modified By : Andrew Beach
// Last Modified On : Tue Jun 13 13:30:00 2022
// Update Count     : 0
//

#include "Waitfor.hpp"

#include <string>

#include "AST/Pass.hpp"
#include "Common/UniqueName.hpp"
#include "InitTweak/InitTweak.hpp"
#include "ResolvExpr/Resolver.hpp"

#include "AST/Print.hpp"

using namespace std::string_literals;
using ResolvExpr::ResolveContext;

/* So this is what this file dones:

void f(int i, float f, A & mutex b, struct foo *  );
void f(int );

...{
        when ( a < 1 ) waitfor( f : a ) { fee(); }
        or timeout( getWaitTime() ) { fy(); }
        or waitfor( g : a ) { foe(); }
        or waitfor( ^?{} : a ) { break; }
        or waitfor( ^?{} ) { break; }
        or when ( a < 1 ) else { fum(); }
}...

                 ||
                 ||
                \||/
                 \/

...{
        {
                __acceptable_t __acceptables_#[4 <num-clauses>];
                bool __do_run_# = false;

                monitor$ * __monitors_#[1 <num-monitors>] = { a };
                if ( a < 1) {
                        void (*__function_#)() = <casts> f;
                        __acceptables_#[0].is_dtor = false;
                        __acceptables_#[0].func = __function_#;
                        __acceptables_#[0].data = __monitors_#;
                        __acceptables_#[0].size = 1;
                        __do_run_# = true;
                }

                // Remaining waitfor clauses go here.

                long long unsigned int __timeout_# = -1;
                if ( true ) {
                        __timeout_# = getWaitTime();
                        __do_run_# = true;
                }

                if ( a < 1 ) {
                        __timeout_# = 0
                        __do_run_# = true;
                }

                short int __index_# = -1;
                __waitfor_mask_t __mask_# = {&__index_#, {__acceptables_#, ?}};
                __waitfor_internal((__waitfor_mask_t&)__mask_#, __timeout_#);

                switch (__index_#) {
                case 0:
                        { { fee(); } break; }
                case 1:
                        { { foe(); } break; }
                case 2:
                        { <modified-break> break; }
                case 3:
                        { <modified-break> break; }
                case -2:
                        { { fy(); } break; }
                case -1:
                        { { foe(); } break; }
                }
        }
}...
*/

namespace Concurrency {

namespace {

class GenerateWaitForCore final :
                public ast::WithSymbolTable, public ast::WithConstTranslationUnit {
        const ast::FunctionDecl * decl_waitfor    = nullptr;
        const ast::StructDecl   * decl_mask       = nullptr;
        const ast::StructDecl   * decl_acceptable = nullptr;
        const ast::StructDecl   * decl_monitor    = nullptr;

        UniqueName namer_acc = "__acceptables_"s;
        UniqueName namer_idx = "__index_"s;
        UniqueName namer_flg = "__do_run_"s;
        UniqueName namer_msk = "__mask_"s;
        UniqueName namer_mon = "__monitors_"s;
        UniqueName namer_tim = "__timeout_"s;
        UniqueName namer_fun = "__function_"s;

        ast::ObjectDecl * declareAcceptables( ast::CompoundStmt * out,
                const CodeLocation & location, unsigned long numClauses );
        ast::ObjectDecl * declareFlag(
                ast::CompoundStmt * out, const CodeLocation & location );
        ast::ExprStmt * makeSetter(
                const CodeLocation & location, ast::ObjectDecl * flag );
        ast::ObjectDecl * declMonitors(
                ast::CompoundStmt * out, const ast::WaitForClause * clause );
        void init_clause( ast::CompoundStmt * out, ast::ObjectDecl * acceptables,
                int index, const ast::WaitForClause * clause, ast::Stmt * setter );
        ast::Expr * init_timeout(
                ast::CompoundStmt * out, const CodeLocation & topLocation,
                const ast::Expr * timeout_time, const ast::Expr * timeout_cond,
                const ast::Stmt * else_stmt, const ast::Expr * else_cond,
                const ast::Stmt * setter );
        ast::Expr * call(
                ast::CompoundStmt * out, const CodeLocation & location,
                size_t numClauses, ast::ObjectDecl * acceptables,
                ast::Expr * timeout );
public:
        void previsit( const ast::FunctionDecl * decl );
        void previsit( const ast::StructDecl * decl );
        ast::Stmt * postvisit( const ast::WaitForStmt * stmt );
};

ast::Expr * makeOpIndex( const CodeLocation & location,
                const ast::DeclWithType * array, unsigned long index ) {
        return new ast::UntypedExpr( location,
                new ast::NameExpr( location, "?[?]" ),
                {
                        new ast::VariableExpr( location, array ),
                        ast::ConstantExpr::from_ulong( location, index ),
                }
        );
}

ast::Expr * makeOpAssign( const CodeLocation & location,
                const ast::Expr * lhs, const ast::Expr * rhs ) {
        return new ast::UntypedExpr( location,
                new ast::NameExpr( location, "?=?" ),
                { lhs, rhs }
        );
}

ast::Expr * makeOpMember( const CodeLocation & location,
                const std::string & mem, const ast::Expr * sue ) {
        return new ast::UntypedMemberExpr( location,
                new ast::NameExpr( location, mem ),
                sue
        );
}

ast::Stmt * makeAccStmt(
                const CodeLocation & location, ast::DeclWithType * object,
                unsigned long index, const std::string & member,
                const ast::Expr * value, const ResolveContext & context
) {
        ast::Expr * expr = makeOpAssign( location,
                makeOpMember( location,
                        member,
                        makeOpIndex( location,
                                object,
                                index
                        )
                ),
                value
        );

        auto result = ResolvExpr::findVoidExpression( expr, context );
        return new ast::ExprStmt( location, result.get() );
}

const ast::Stmt * maybeCond( const CodeLocation & location,
                const ast::Expr * cond, std::list<ast::ptr<ast::Stmt>> && stmts ) {
        ast::Stmt * block = new ast::CompoundStmt( location, std::move( stmts ) );
        return (cond) ? new ast::IfStmt( location, cond, block ) : block;
}

const ast::VariableExpr * extractVariable( const ast::Expr * func ) {
        if ( auto var = dynamic_cast<const ast::VariableExpr *>( func ) ) {
                return var;
        }
        auto cast = strict_dynamic_cast<const ast::CastExpr *>( func );
        return cast->arg.strict_as<ast::VariableExpr>();
}

const ast::Expr * detectIsDtor(
                const CodeLocation & location, const ast::Expr * func ) {
        const ast::VariableExpr * typed_func = extractVariable( func );
        bool is_dtor = InitTweak::isDestructor(
                typed_func->var.strict_as<ast::FunctionDecl>() );
        return ast::ConstantExpr::from_bool( location, is_dtor );
}

ast::ObjectDecl * GenerateWaitForCore::declareAcceptables(
                ast::CompoundStmt * out,
                const CodeLocation & location, unsigned long numClauses ) {
        ast::ObjectDecl * acceptables = new ast::ObjectDecl( location,
                namer_acc.newName(),
                new ast::ArrayType(
                        new ast::StructInstType( decl_acceptable ),
                        ast::ConstantExpr::from_ulong( location, numClauses ),
                        ast::FixedLen,
                        ast::DynamicDim
                )
        );
        out->push_back( new ast::DeclStmt( location, acceptables ) );

        ast::Expr * set = new ast::UntypedExpr( location,
                new ast::NameExpr( location, "__builtin_memset" ),
                {
                        new ast::VariableExpr( location, acceptables ),
                        ast::ConstantExpr::from_int( location, 0 ),
                        new ast::SizeofExpr( location,
                                new ast::VariableExpr( location, acceptables ) ),
                }
        );
        ResolveContext context{ symtab, transUnit().global };
        auto result = ResolvExpr::findVoidExpression( set, context );
        out->push_back( new ast::ExprStmt( location, result.get() ) );

        return acceptables;
}

ast::ObjectDecl * GenerateWaitForCore::declareFlag(
                ast::CompoundStmt * out, const CodeLocation & location ) {
        ast::ObjectDecl * flag = new ast::ObjectDecl( location,
                namer_flg.newName(),
                new ast::BasicType( ast::BasicKind::Bool ),
                new ast::SingleInit( location,
                        ast::ConstantExpr::from_ulong( location, 0 )
                )
        );
        out->push_back( new ast::DeclStmt( location, flag ) );
        return flag;
}

ast::ExprStmt * GenerateWaitForCore::makeSetter(
                const CodeLocation & location, ast::ObjectDecl * flag ) {
        ast::Expr * expr = new ast::UntypedExpr( location,
                new ast::NameExpr( location, "?=?" ),
                {
                        new ast::VariableExpr( location, flag ),
                        ast::ConstantExpr::from_ulong( location, 1 ),
                }
        );
        ResolveContext context{ symtab, transUnit().global };
        auto result = ResolvExpr::findVoidExpression( expr, context );
        return new ast::ExprStmt( location, result.get() );
}

ast::ObjectDecl * GenerateWaitForCore::declMonitors(
                ast::CompoundStmt * out,
                const ast::WaitForClause * clause ) {
        const CodeLocation & location = clause->location;
        ast::ObjectDecl * monitor = new ast::ObjectDecl( location,
                namer_mon.newName(),
                new ast::ArrayType(
                        new ast::PointerType(
                                new ast::StructInstType( decl_monitor )
                        ),
                        ast::ConstantExpr::from_ulong( location, clause->target_args.size() ),
                        ast::FixedLen,
                        ast::DynamicDim
                ),
                new ast::ListInit( location,
                        map_range<std::vector<ast::ptr<ast::Init>>>(
                                clause->target_args,
                                []( const ast::Expr * expr ){
                                        return new ast::SingleInit( expr->location, expr ); }
                        )
                )
        );
        out->push_back( new ast::DeclStmt( location, monitor ) );
        return monitor;
}

void GenerateWaitForCore::init_clause(
                ast::CompoundStmt * out,
                ast::ObjectDecl * acceptables,
                int index,
                const ast::WaitForClause * clause,
                ast::Stmt * setter ) {
        const CodeLocation & location = clause->location;
        const ast::ObjectDecl * monitors = declMonitors( out, clause );
        ast::Type * fptr_t = new ast::PointerType(
                        new ast::FunctionType( ast::VariableArgs ) );

        const ast::VariableExpr * variableExpr =
                clause->target.as<ast::VariableExpr>();
        ast::Expr * castExpr = new ast::CastExpr(
                location,
                new ast::CastExpr(
                        location,
                        clause->target,
                        ast::deepCopy( variableExpr->result.get() ),
                        ast::GeneratedCast ),
                fptr_t,
                ast::GeneratedCast );

        ast::ObjectDecl * funcDecl = new ast::ObjectDecl( location,
                namer_fun.newName(),
                ast::deepCopy( fptr_t ),
                new ast::SingleInit( location, castExpr )
                );
        ast::Expr * funcExpr = new ast::VariableExpr( location, funcDecl );
        out->push_back( new ast::DeclStmt( location, funcDecl ) );

        ResolveContext context{ symtab, transUnit().global };
        out->push_back( maybeCond( location, clause->when_cond.get(), {
                makeAccStmt( location, acceptables, index, "is_dtor",
                        detectIsDtor( location, clause->target ), context ),
                makeAccStmt( location, acceptables, index, "func",
                        funcExpr, context ),
                makeAccStmt( location, acceptables, index, "data",
                        new ast::VariableExpr( location, monitors ), context ),
                makeAccStmt( location, acceptables, index, "size",
                        ast::ConstantExpr::from_ulong( location,
                                clause->target_args.size() ), context ),
                ast::deepCopy( setter ),
        } ) );
}

ast::Expr * GenerateWaitForCore::init_timeout(
                ast::CompoundStmt * out,
                const CodeLocation & topLocation,
                const ast::Expr * timeout_time,
                const ast::Expr * timeout_cond,
                const ast::Stmt * else_stmt,
                const ast::Expr * else_cond,
                const ast::Stmt * setter ) {
        ast::ObjectDecl * timeout = new ast::ObjectDecl( topLocation,
                namer_tim.newName(),
                new ast::BasicType( ast::BasicKind::LongLongUnsignedInt ),
                new ast::SingleInit( topLocation,
                        ast::ConstantExpr::from_int( topLocation, -1 )
                )
        );
        out->push_back( new ast::DeclStmt( topLocation, timeout ) );

        if ( timeout_time ) {
                const CodeLocation & location = timeout_time->location;
                out->push_back( maybeCond( location, timeout_cond, {
                        new ast::ExprStmt( location,
                                makeOpAssign(
                                        location,
                                        new ast::VariableExpr( location, timeout ),
                                        timeout_time
                                )
                        ),
                        ast::deepCopy( setter ),
                } ) );
        }

        // We only care about the else_stmt's presence and location.
        if ( else_stmt ) {
                const CodeLocation & location = else_stmt->location;
                out->push_back( maybeCond( location, else_cond, {
                        new ast::ExprStmt( location,
                                makeOpAssign(
                                        location,
                                        new ast::VariableExpr( location, timeout ),
                                        ast::ConstantExpr::from_ulong( location, 0 )
                                )
                        ),
                        ast::deepCopy( setter ),
                } ) );
        }

        return new ast::VariableExpr( topLocation, timeout );
}

ast::Expr * GenerateWaitForCore::call(
        ast::CompoundStmt * out,
        const CodeLocation & location,
        size_t numClauses,
        ast::ObjectDecl * acceptables,
        ast::Expr * timeout
) {
        ast::ObjectDecl * index = new ast::ObjectDecl( location,
                namer_idx.newName(),
                new ast::BasicType( ast::BasicKind::ShortSignedInt ),
                new ast::SingleInit( location,
                        ast::ConstantExpr::from_int( location, -1 )
                )
        );
        out->push_back( new ast::DeclStmt( location, index ) );

        ast::ObjectDecl * mask = new ast::ObjectDecl( location,
                namer_msk.newName(),
                new ast::StructInstType( decl_mask ),
                new ast::ListInit( location, {
                        new ast::SingleInit( location,
                                new ast::AddressExpr( location,
                                        new ast::VariableExpr( location, index )
                                )
                        ),
                        new ast::ListInit( location, {
                                new ast::SingleInit( location,
                                        new ast::VariableExpr( location, acceptables )
                                ),
                                new ast::SingleInit( location,
                                        ast::ConstantExpr::from_ulong( location, numClauses )
                                ),
                        }),
                })
        );
        out->push_back( new ast::DeclStmt( location, mask ) );

        ast::ApplicationExpr * waitforMask = new ast::ApplicationExpr( location,
                ast::VariableExpr::functionPointer( location, decl_waitfor ),
                {
                        new ast::CastExpr(
                                new ast::VariableExpr( location, mask ),
                                new ast::ReferenceType(
                                        new ast::StructInstType( decl_mask )
                                )
                        ),
                        timeout
                }
        );
        out->push_back( new ast::ExprStmt( location, waitforMask ) );

        return new ast::VariableExpr( location, index );
}

ast::Stmt * choose( const ast::WaitForStmt * waitfor, ast::Expr * result ) {
        const CodeLocation & location = waitfor->location;

        ast::SwitchStmt * theSwitch = new ast::SwitchStmt( location,
                result,
                std::vector<ast::ptr<ast::CaseClause>>()
        );

        for ( const auto & [i, clause] : enumerate( waitfor->clauses ) ) {
                theSwitch->cases.push_back(
                        new ast::CaseClause( location,
                                ast::ConstantExpr::from_ulong( location, i ),
                                {
                                        new ast::CompoundStmt( location, {
                                                clause->stmt,
                                                new ast::BranchStmt( location,
                                                        ast::BranchStmt::Break,
                                                        ast::Label( location )
                                                )
                                        })
                                }
                        )
                );
        }

        if ( waitfor->timeout_stmt ) {
                theSwitch->cases.push_back(
                        new ast::CaseClause( location,
                                ast::ConstantExpr::from_int( location, -2 ),
                                {
                                        new ast::CompoundStmt( location, {
                                                waitfor->timeout_stmt,
                                                new ast::BranchStmt( location,
                                                        ast::BranchStmt::Break,
                                                        ast::Label( location )
                                                )
                                        })
                                }
                        )
                );
        }

        if ( waitfor->else_stmt ) {
                theSwitch->cases.push_back(
                        new ast::CaseClause( location,
                                ast::ConstantExpr::from_int( location, -1 ),
                                {
                                        new ast::CompoundStmt( location, {
                                                waitfor->else_stmt,
                                                new ast::BranchStmt( location,
                                                        ast::BranchStmt::Break,
                                                        ast::Label( location )
                                                )
                                        })
                                }
                        )
                );
        }

        return theSwitch;
}

void GenerateWaitForCore::previsit( const ast::FunctionDecl * decl ) {
        if ( "__waitfor_internal" == decl->name ) {
                decl_waitfor = decl;
        }
}

void GenerateWaitForCore::previsit( const ast::StructDecl * decl ) {
        if ( !decl->body ) {
                return;
        } else if ( "__acceptable_t" == decl->name ) {
                assert( !decl_acceptable );
                decl_acceptable = decl;
        } else if ( "__waitfor_mask_t" == decl->name ) {
                assert( !decl_mask );
                decl_mask = decl;
        } else if ( "monitor$" == decl->name ) {
                assert( !decl_monitor );
                decl_monitor = decl;
        }
}

ast::Stmt * GenerateWaitForCore::postvisit( const ast::WaitForStmt * stmt ) {
        if ( !decl_monitor || !decl_acceptable || !decl_mask ) {
                SemanticError( stmt, "waitfor keyword requires monitors to be in scope, add #include <monitor.hfa>" );
        }

        const CodeLocation & location = stmt->location;
        ast::CompoundStmt * comp = new ast::CompoundStmt( location );

        ast::ObjectDecl * acceptables = declareAcceptables( comp, location, stmt->clauses.size() );
        ast::ObjectDecl * flag        = declareFlag( comp, location );
        ast::Stmt       * setter      = makeSetter( location, flag );

        for ( const auto & [i, clause] : enumerate( stmt->clauses ) ) {
                init_clause( comp, acceptables, i, clause, setter );
        }

        ast::Expr * timeout = init_timeout(
                comp,
                location,
                stmt->timeout_time,
                stmt->timeout_cond,
                stmt->else_stmt,
                stmt->else_cond,
                setter
        );

        ast::CompoundStmt * compound = new ast::CompoundStmt( location );
        comp->push_back( new ast::IfStmt( location,
                new ast::VariableExpr( location, flag ),
                compound,
                nullptr
        ));

        ast::Expr * result = call(
                compound, location, stmt->clauses.size(), acceptables, timeout );
        compound->push_back( choose( stmt, result ) );
        return comp;
}

} // namespace

void generateWaitFor( ast::TranslationUnit & translationUnit ) {
        ast::Pass<GenerateWaitForCore>::run( translationUnit );
}

} // namespace Concurrency

// Local Variables: //
// tab-width: 4 //
// mode: c++ //
// compile-command: "make install" //
// End: //