source: src/InitTweak/InitTweak.cpp @ b8561fa

//
// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// InitTweak.cpp --
//
// Author           : Rob Schluntz
// Created On       : Fri May 13 11:26:36 2016
// Last Modified By : Andrew Beach
// Last Modified On : Wed Sep 22  9:50:00 2022
// Update Count     : 21
//

#include "InitTweak.hpp"

#include <algorithm>                  // for find, all_of
#include <cassert>                    // for assertf, assert, strict_dynamic_...
#include <iostream>                   // for ostream, cerr, endl
#include <iterator>                   // for back_insert_iterator, back_inser...
#include <memory>                     // for __shared_ptr
#include <vector>

#include "AST/Expr.hpp"
#include "AST/Init.hpp"
#include "AST/Inspect.hpp"
#include "AST/Node.hpp"
#include "AST/Pass.hpp"
#include "AST/Stmt.hpp"
#include "AST/Type.hpp"
#include "CodeGen/OperatorTable.hpp"  // for isConstructor, isDestructor, isC...
#include "Common/SemanticError.hpp"   // for SemanticError
#include "Common/ToString.hpp"        // for toCString
#include "Common/UniqueName.hpp"      // for UniqueName
#include "GenPoly/GenPoly.hpp"        // for getFunctionType
#include "ResolvExpr/Unify.hpp"       // for typesCompatibleIgnoreQualifiers
#include "Tuples/Tuples.hpp"          // for Tuples::isTtype

namespace InitTweak {

// Forward declared, because it is used as a parent type.
class InitExpander::ExpanderImpl {
public:
        virtual ~ExpanderImpl() = default;
        virtual std::vector< ast::ptr< ast::Expr > > next( IndexList & indices ) = 0;
        virtual ast::ptr< ast::Stmt > buildListInit(
                ast::UntypedExpr * callExpr, IndexList & indices ) = 0;
};

namespace {
        struct HasDesignations : public ast::WithShortCircuiting {
                bool result = false;

                void previsit( const ast::Node * ) {
                        // Short circuit if we already know there are designations.
                        if ( result ) visit_children = false;
                }

                void previsit( const ast::Designation * des ) {
                        // Short circuit if we already know there are designations.
                        if ( result ) visit_children = false;
                        else if ( !des->designators.empty() ) {
                                result = true;
                                visit_children = false;
                        }
                }
        };

        struct InitDepthChecker {
                bool result = true;
                const ast::Type * type;
                int curDepth = 0, maxDepth = 0;
                InitDepthChecker( const ast::Type * type ) : type( type ) {
                        const ast::Type * t = type;
                        while ( auto at = dynamic_cast< const ast::ArrayType * >( t ) ) {
                                maxDepth++;
                                t = at->base;
                        }
                        maxDepth++;
                }
                void previsit( ast::ListInit const * ) {
                        curDepth++;
                        if ( curDepth > maxDepth ) result = false;
                }
                void postvisit( ast::ListInit const * ) {
                        curDepth--;
                }
        };

        struct InitFlattener : public ast::WithShortCircuiting {
                std::vector< ast::ptr< ast::Expr > > argList;

                void previsit( const ast::SingleInit * singleInit ) {
                        visit_children = false;
                        argList.emplace_back( singleInit->value );
                }
        };

        template< typename Out >
        void buildCallExpr(
                ast::UntypedExpr * callExpr, const ast::Expr * index, const ast::Expr * dimension,
                const ast::Init * init, Out & out
        ) {
                const CodeLocation & loc = init->location;

                auto cond = new ast::UntypedExpr{
                        loc, new ast::NameExpr{ loc, "?<?" }, { index, dimension } };

                std::vector< ast::ptr< ast::Expr > > args = makeInitList( init );
                splice( callExpr->args, args );

                out.emplace_back( new ast::IfStmt{ loc, cond, new ast::ExprStmt{ loc, callExpr } } );

                out.emplace_back( new ast::ExprStmt{
                        loc, new ast::UntypedExpr{ loc, new ast::NameExpr{ loc, "++?" }, { index } } } );
        }

        template< typename Out >
        void build(
                ast::UntypedExpr * callExpr, const InitExpander::IndexList & indices,
                const ast::Init * init, Out & out
        ) {
                if ( indices.empty() ) return;

                unsigned idx = 0;

                const ast::Expr * index = indices[idx++];
                assert( idx != indices.size() );
                const ast::Expr * dimension = indices[idx++];

                if ( idx == indices.size() ) {
                        if ( auto listInit = dynamic_cast< const ast::ListInit * >( init ) ) {
                                for ( const ast::Init * init : *listInit ) {
                                        buildCallExpr( shallowCopy(callExpr), index, dimension, init, out );
                                }
                        } else {
                                buildCallExpr( shallowCopy(callExpr), index, dimension, init, out );
                        }
                } else {
                        const CodeLocation & loc = init->location;

                        unsigned long cond = 0;
                        auto listInit = dynamic_cast< const ast::ListInit * >( init );
                        if ( ! listInit ) { SemanticError( loc, "unbalanced list initializers" ); }

                        static UniqueName targetLabel( "L__autogen__" );
                        ast::Label switchLabel{
                                loc, targetLabel.newName(), { new ast::Attribute{ "unused" } } };

                        std::vector< ast::ptr< ast::CaseClause > > branches;
                        for ( const ast::Init * init : *listInit ) {
                                auto condition = ast::ConstantExpr::from_ulong( loc, cond );
                                ++cond;

                                std::vector< ast::ptr< ast::Stmt > > stmts;
                                build( callExpr, indices, init, stmts );
                                stmts.emplace_back(
                                        new ast::BranchStmt{ loc, ast::BranchStmt::Break, switchLabel } );
                                branches.emplace_back( new ast::CaseClause{ loc, condition, std::move( stmts ) } );
                        }
                        out.emplace_back( new ast::SwitchStmt{ loc, index, std::move( branches ) } );
                        out.emplace_back( new ast::NullStmt{ loc, { switchLabel } } );
                }
        }

        class InitImpl final : public InitExpander::ExpanderImpl {
                ast::ptr< ast::Init > init;
        public:
                InitImpl( const ast::Init * i ) : init( i ) {}

                std::vector< ast::ptr< ast::Expr > > next( InitExpander::IndexList & ) override {
                        return makeInitList( init );
                }

                ast::ptr< ast::Stmt > buildListInit(
                        ast::UntypedExpr * callExpr, InitExpander::IndexList & indices
                ) override {
                        // If array came with an initializer list, initialize each element. We may have more
                        // initializers than elements of the array; need to check at each index that we have
                        // not exceeded size. We may have fewer initializers than elements in the array; need
                        // to default-construct remaining elements. To accomplish this, generate switch
                        // statement consuming all of expander's elements

                        if ( ! init ) return {};

                        std::list< ast::ptr< ast::Stmt > > stmts;
                        build( callExpr, indices, init, stmts );
                        if ( stmts.empty() ) {
                                return {};
                        } else if ( 1 == stmts.size() ) {
                                return std::move( stmts.front() );
                        } else {
                                auto block = new ast::CompoundStmt{ init->location, std::move( stmts ) };
                                init = nullptr;  // consumed in creating the list init
                                return block;
                        }
                }
        };

        class ExprImpl final : public InitExpander::ExpanderImpl {
                ast::ptr< ast::Expr > arg;
        public:
                ExprImpl( const ast::Expr * a ) : arg( a ) {}

                std::vector< ast::ptr< ast::Expr > > next(
                        InitExpander::IndexList & indices
                ) override {
                        if ( !arg ) return {};

                        const CodeLocation & loc = arg->location;
                        const ast::Expr * expr = arg;
                        for ( auto it = indices.rbegin(); it != indices.rend(); ++it ) {
                                // Go through indices and layer on subscript exprs ?[?].
                                ++it;
                                expr = new ast::UntypedExpr{
                                        loc, new ast::NameExpr{ loc, "?[?]" }, { expr, *it } };
                        }
                        return { expr };
                }

                ast::ptr< ast::Stmt > buildListInit(
                        ast::UntypedExpr *, InitExpander::IndexList &
                ) override {
                        return {};
                }
        };

        struct CallFinder final {
                std::vector< const ast::Expr * > matches;
                const std::vector< std::string > names;

                CallFinder( std::vector< std::string > && ns ) : matches(), names( std::move(ns) ) {}

                void handleCallExpr( const ast::Expr * expr ) {
                        std::string fname = getFunctionName( expr );
                        if ( std::find( names.begin(), names.end(), fname ) != names.end() ) {
                                matches.emplace_back( expr );
                        }
                }

                void postvisit( const ast::ApplicationExpr * expr ) { handleCallExpr( expr ); }
                void postvisit( const ast::UntypedExpr *     expr ) { handleCallExpr( expr ); }
        };

        template <typename Predicate>
        bool allofCtorDtor( const ast::Stmt * stmt, const Predicate & pred ) {
                std::vector< const ast::Expr * > callExprs = collectCtorDtorCalls( stmt );
                return std::all_of( callExprs.begin(), callExprs.end(), pred );
        }

        struct ConstExprChecker : public ast::WithShortCircuiting {
                // Most expressions are not const-expr.
                void previsit( const ast::Expr * ) { result = false; visit_children = false; }

                void previsit( const ast::AddressExpr *addressExpr ) {
                        visit_children = false;
                        const ast::Expr * arg = addressExpr->arg;

                        // Address of a variable or member expression is const-expr.
                        if ( !dynamic_cast< const ast::NameExpr * >( arg )
                                && !dynamic_cast< const ast::VariableExpr * >( arg )
                                && !dynamic_cast< const ast::MemberExpr * >( arg )
                                && !dynamic_cast< const ast::UntypedMemberExpr * >( arg ) ) result = false;
                }

                // These expressions may be const expr, depending on their children.
                void previsit( const ast::SizeofExpr * ) {}
                void previsit( const ast::AlignofExpr * ) {}
                void previsit( const ast::UntypedOffsetofExpr * ) {}
                void previsit( const ast::OffsetofExpr * ) {}
                void previsit( const ast::OffsetPackExpr * ) {}
                void previsit( const ast::CommaExpr * ) {}
                void previsit( const ast::LogicalExpr * ) {}
                void previsit( const ast::ConditionalExpr * ) {}
                void previsit( const ast::CastExpr * ) {}
                void previsit( const ast::ConstantExpr * ) {}

                void previsit( const ast::VariableExpr * varExpr ) {
                        visit_children = false;

                        if ( auto inst = varExpr->result.as<ast::EnumInstType>() ) {
                                long long int value;
                                if ( inst->base->valueOf( varExpr->var, value ) ) {
                                        // enumerators are const expr
                                        return;
                                }
                        }
                        result = false;
                }

                bool result = true;
        };
} // namespace

bool isAssignment( const ast::FunctionDecl * decl ) {
        return CodeGen::isAssignment( decl->name ) && isCopyFunction( decl );
}

bool isDestructor( const ast::FunctionDecl * decl ) {
        return CodeGen::isDestructor( decl->name );
}

bool isDefaultConstructor( const ast::FunctionDecl * decl ) {
        return CodeGen::isConstructor( decl->name ) && 1 == decl->params.size();
}

bool isCopyConstructor( const ast::FunctionDecl * decl ) {
        return CodeGen::isConstructor( decl->name ) && 2 == decl->params.size();
}

bool isCopyFunction( const ast::FunctionDecl * decl ) {
        const ast::FunctionType * ftype = decl->type;
        if ( ftype->params.size() != 2 ) return false;

        const ast::Type * t1 = ast::getPointerBase( ftype->params.front() );
        if ( ! t1 ) return false;
        const ast::Type * t2 = ftype->params.back();

        return ResolvExpr::typesCompatibleIgnoreQualifiers( t1, t2 );
}

const ast::Type * getTypeofThis( const ast::FunctionType * ftype ) {
        assertf( ftype, "getTypeofThis: nullptr ftype" );
        const std::vector<ast::ptr<ast::Type>> & params = ftype->params;
        assertf( !params.empty(), "getTypeofThis: ftype with 0 parameters: %s",
                        toCString( ftype ) );
        const ast::ReferenceType * refType =
                params.front().strict_as<ast::ReferenceType>();
        return refType->base;
}

const ast::ObjectDecl * getParamThis(const ast::FunctionDecl * func) {
        assertf( func, "getParamThis: nullptr ftype" );
        auto & params = func->params;
        assertf( !params.empty(), "getParamThis: ftype with 0 parameters: %s", toCString( func ));
        return params.front().strict_as<ast::ObjectDecl>();
}

// looks like some other such codegen uses UntypedExpr and does not create fake function. should revisit afterwards
// following passes may accidentally resolve this expression if returned as untyped...
ast::Expr * createBitwiseAssignment(const ast::Expr * dst, const ast::Expr * src) {
        static ast::ptr<ast::FunctionDecl> assign = nullptr;
        if (!assign) {
                auto td = new ast::TypeDecl(CodeLocation(), "T", {}, nullptr, ast::TypeDecl::Dtype, true);
                assign = new ast::FunctionDecl(CodeLocation(), "?=?", {td}, {},
                { new ast::ObjectDecl(CodeLocation(), "_dst", new ast::ReferenceType(new ast::TypeInstType("T", td))),
                  new ast::ObjectDecl(CodeLocation(), "_src", new ast::TypeInstType("T", td))},
                { new ast::ObjectDecl(CodeLocation(), "_ret", new ast::TypeInstType("T", td))}, nullptr, {}, ast::Linkage::Intrinsic);
        }
        if (dst->result.as<ast::ReferenceType>()) {
                for (int depth = dst->result->referenceDepth(); depth > 0; depth--) {
                        dst = new ast::AddressExpr(dst);
                }
        } else {
                dst = new ast::CastExpr(dst, new ast::ReferenceType(dst->result, {}));
        }
        if (src->result.as<ast::ReferenceType>()) {
                for (int depth = src->result->referenceDepth(); depth > 0; depth--) {
                        src = new ast::AddressExpr(src);
                }
        }
        auto var = ast::VariableExpr::functionPointer(dst->location, assign);
        auto app = new ast::ApplicationExpr(dst->location, var, {dst, src});
        // Skip the resolver, just set the result to the correct type.
        app->result = ast::deepCopy( src->result );
        return app;
}

std::vector< ast::ptr< ast::Expr > > makeInitList( const ast::Init * init ) {
        ast::Pass< InitFlattener > flattener;
        maybe_accept( init, flattener );
        return std::move( flattener.core.argList );
}

bool tryConstruct( const ast::DeclWithType * dwt ) {
        auto objDecl = dynamic_cast< const ast::ObjectDecl * >( dwt );
        if ( !objDecl ) return false;
        return (objDecl->init == nullptr ||
                        ( objDecl->init != nullptr && objDecl->init->maybeConstructed ))
                && !objDecl->storage.is_extern
                && isConstructable( objDecl->type );
}

bool isConstructable( const ast::Type * type ) {
        return !dynamic_cast< const ast::VarArgsType * >( type ) && !dynamic_cast< const ast::ReferenceType * >( type )
                && !dynamic_cast< const ast::FunctionType * >( type ) && !Tuples::isTtype( type );
}

bool isDesignated( const ast::Init * init ) {
        return ( init ) ? ast::Pass<HasDesignations>::read( init ) : false;
}

bool checkInitDepth( const ast::ObjectDecl * objDecl ) {
        return ( objDecl->init ) ? ast::Pass<InitDepthChecker>::read(
                objDecl->init.get(), objDecl->type.get() ) : true;
}

bool isIntrinsicSingleArgCallStmt( const ast::Stmt * stmt ) {
        return allofCtorDtor( stmt, []( const ast::Expr * callExpr ){
                if ( const ast::ApplicationExpr * appExpr = isIntrinsicCallExpr( callExpr ) ) {
                        const ast::FunctionType * funcType =
                                GenPoly::getFunctionType( appExpr->func->result );
                        assert( funcType );
                        return funcType->params.size() == 1;
                }
                return false;
        });
}

std::vector< const ast::Expr * > collectCtorDtorCalls( const ast::Stmt * stmt ) {
        ast::Pass< CallFinder > finder{ std::vector< std::string >{ "?{}", "^?{}" } };
        maybe_accept( stmt, finder );
        return std::move( finder.core.matches );
}

bool isConstExpr( const ast::Expr * expr ) {
        return ( expr ) ? ast::Pass<ConstExprChecker>::read( expr ) : true;
}

bool isConstExpr( const ast::Init * init ) {
        // for all intents and purposes, no initializer means const expr
        return ( init ) ? ast::Pass<ConstExprChecker>::read( init ) : true;
}

#if defined( __x86_64 ) || defined( __i386 ) // assembler comment to prevent assembler warning message
        #define ASM_COMMENT "#"
#else // defined( __ARM_ARCH )
        #define ASM_COMMENT "//"
#endif
static const char * const data_section =  ".data" ASM_COMMENT;
static const char * const tlsd_section = ".tdata" ASM_COMMENT;

void addDataSectionAttribute( ast::ObjectDecl * objDecl ) {
        const bool is_tls = objDecl->storage.is_threadlocal_any();
        const char * section = is_tls ? tlsd_section : data_section;
        objDecl->attributes.push_back(new ast::Attribute("section", {
                ast::ConstantExpr::from_string(objDecl->location, section)
        }));
}

InitExpander::InitExpander( const ast::Init * init )
: expander( new InitImpl{ init } ), crnt(), indices() {}

InitExpander::InitExpander( const ast::Expr * expr )
: expander( new ExprImpl{ expr } ), crnt(), indices() {}

std::vector< ast::ptr< ast::Expr > > InitExpander::operator* () { return crnt; }

InitExpander & InitExpander::operator++ () {
        crnt = expander->next( indices );
        return *this;
}

/// builds statement which has the same semantics as a C-style list initializer (for array
/// initializers) using callExpr as the base expression to perform initialization
ast::ptr< ast::Stmt > InitExpander::buildListInit( ast::UntypedExpr * callExpr ) {
        return expander->buildListInit( callExpr, indices );
}

void InitExpander::addArrayIndex( const ast::Expr * index, const ast::Expr * dimension ) {
        indices.emplace_back( index );
        indices.emplace_back( dimension );
}

void InitExpander::clearArrayIndices() { indices.clear(); }

bool InitExpander::addReference() {
        for ( ast::ptr< ast::Expr > & expr : crnt ) {
                expr = new ast::AddressExpr{ expr };
        }
        return !crnt.empty();
}

} // namespace InitTweak