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source: src/GenPoly/Lvalue.cc @ 2dda05d

ADTarm-ehast-experimentalenumforall-pointer-decayjacob/cs343-translationnew-ast-unique-exprpthread-emulationqualifiedEnum

Last change on this file since 2dda05d was 07de76b, checked in by Peter A. Buhr <pabuhr@…>, 5 years ago
remove file TypeVar?.h* and put TypeVar::Kind into TypeDecl?, move LinkageSpec?.* from directory Parse to SynTree?
Property mode set to `100644`
File size: 23.5 KB

Rev	Line
[51587aa]	1	//
	2	// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
	3	//
	4	// The contents of this file are covered under the licence agreement in the
	5	// file "LICENCE" distributed with Cforall.
	6	//
[906e24d]	7	// Lvalue.cc --
[51587aa]	8	//
	9	// Author : Richard C. Bilson
	10	// Created On : Mon May 18 07:44:20 2015
[01aeade]	11	// Last Modified By : Peter A. Buhr
[07de76b]	12	// Last Modified On : Fri Dec 13 23:14:38 2019
	13	// Update Count : 7
[51587aa]	14	//
[51b7345]	15
[e3e16bc]	16	#include <cassert> // for strict_dynamic_cast
[08fc48f]	17	#include <string> // for string
[51b7345]	18
[07de76b]	19	#include "Common/UniqueName.h"
[8135d4c]	20	#include "Common/PassVisitor.h"
[08fc48f]	21	#include "GenPoly.h" // for isPolyType
[51b7345]	22	#include "Lvalue.h"
	23
[2bfc6b2]	24	#include "InitTweak/InitTweak.h"
[08fc48f]	25	#include "ResolvExpr/TypeEnvironment.h" // for AssertionSet, OpenVarSet
	26	#include "ResolvExpr/Unify.h" // for unify
[51b7345]	27	#include "ResolvExpr/typeops.h"
[08fc48f]	28	#include "SymTab/Indexer.h" // for Indexer
[07de76b]	29	#include "SynTree/LinkageSpec.h" // for Spec, isBuiltin, Intrinsic
[08fc48f]	30	#include "SynTree/Declaration.h" // for Declaration, FunctionDecl
	31	#include "SynTree/Expression.h" // for Expression, ConditionalExpr
	32	#include "SynTree/Mutator.h" // for mutateAll, Mutator
	33	#include "SynTree/Statement.h" // for ReturnStmt, Statement (ptr o...
	34	#include "SynTree/Type.h" // for PointerType, Type, FunctionType
	35	#include "SynTree/Visitor.h" // for Visitor, acceptAll
[2bfc6b2]	36	#include "Validate/FindSpecialDecls.h" // for dereferenceOperator
[1d776fd]	37
[cb43451]	38	#if 0
	39	#define PRINT(x) x
	40	#else
	41	#define PRINT(x)
	42	#endif
	43
[51b7345]	44	namespace GenPoly {
[01aeade]	45	namespace {
[9a34b5a]	46	// TODO: fold this into the general createDeref function??
	47	Expression * mkDeref( Expression * arg ) {
[2bfc6b2]	48	if ( Validate::dereferenceOperator ) {
[a9b1b0c]	49	// note: reference depth can be arbitrarily deep here, so peel off the outermost pointer/reference, not just pointer because they are effecitvely equivalent in this pass
[2bfc6b2]	50	VariableExpr * deref = new VariableExpr( Validate::dereferenceOperator );
[0690350]	51	deref->result = new PointerType( Type::Qualifiers(), deref->result );
	52	Type * base = InitTweak::getPointerBase( arg->result );
	53	assertf( base, "expected pointer type in dereference (type was %s)", toString( arg->result ).c_str() );
[9a34b5a]	54	ApplicationExpr * ret = new ApplicationExpr( deref, { arg } );
[0690350]	55	delete ret->result;
	56	ret->result = base->clone();
[9a34b5a]	57	return ret;
	58	} else {
	59	return UntypedExpr::createDeref( arg );
	60	}
	61	}
	62
[78cdb06]	63	struct ReferenceConversions final : public WithStmtsToAdd, public WithGuards {
[1d776fd]	64	Expression * postmutate( CastExpr * castExpr );
[8a6cf7e]	65	Expression * postmutate( AddressExpr * addrExpr );
[01aeade]	66	};
	67
[1d776fd]	68	/// Intrinsic functions that take reference parameters don't REALLY take reference parameters -- their reference arguments must always be implicitly dereferenced.
	69	struct FixIntrinsicArgs final {
[8499c707]	70	Expression * postmutate( ApplicationExpr * appExpr );
[1d776fd]	71	};
	72
[9aaac6e9]	73	struct FixIntrinsicResult final : public WithGuards {
[78cdb06]	74	enum {
	75	NoSkip,
	76	Skip,
	77	SkipInProgress
	78	} skip = NoSkip;
	79
	80	void premutate( AsmExpr * ) { GuardValue( skip ); skip = Skip; }
	81	void premutate( ApplicationExpr * ) { GuardValue( skip ); skip = (skip == Skip) ? SkipInProgress : NoSkip; }
	82
	83
[8499c707]	84	Expression * postmutate( ApplicationExpr * appExpr );
[9aaac6e9]	85	void premutate( FunctionDecl * funcDecl );
	86	bool inIntrinsic = false;
[8499c707]	87	};
[1d776fd]	88
	89	/// Replace reference types with pointer types
	90	struct ReferenceTypeElimination final {
	91	Type * postmutate( ReferenceType * refType );
[01aeade]	92	};
[b6fd751]	93
	94	/// GCC-like Generalized Lvalues (which have since been removed from GCC)
	95	/// https://gcc.gnu.org/onlinedocs/gcc-3.4.6/gcc/Lvalues.html#Lvalues
	96	/// Replaces &(a,b) with (a, &b), &(a ? b : c) with (a ? &b : &c)
[d335627]	97	struct GeneralizedLvalue final : public WithVisitorRef<GeneralizedLvalue> {
[1d776fd]	98	Expression * postmutate( AddressExpr * addressExpr );
[9236060]	99	Expression * postmutate( MemberExpr * memExpr );
[acd7c5dd]	100
	101	template<typename Func>
	102	Expression * applyTransformation( Expression * expr, Expression * arg, Func mkExpr );
[b6fd751]	103	};
[cb43451]	104
	105	/// Removes redundant &/& pattern that this pass can generate
	106	struct CollapseAddrDeref final {
	107	Expression * postmutate( AddressExpr * addressExpr );
	108	Expression * postmutate( ApplicationExpr * appExpr );
	109	};
[8499c707]	110
[a3323db1]	111	struct AddrRef final : public WithGuards, public WithVisitorRef<AddrRef>, public WithShortCircuiting {
[8499c707]	112	void premutate( AddressExpr * addrExpr );
	113	Expression * postmutate( AddressExpr * addrExpr );
	114	void premutate( Expression * expr );
[a3323db1]	115	void premutate( ApplicationExpr * appExpr );
	116	void premutate( SingleInit * init );
	117
	118	void handleNonAddr( Expression * );
[8499c707]	119
	120	bool first = true;
	121	bool current = false;
	122	int refDepth = 0;
[a3323db1]	123	bool addCast = false;
[8499c707]	124	};
[01aeade]	125	} // namespace
	126
[b0440b7]	127	static bool referencesEliminated = false;
	128	// used by UntypedExpr::createDeref to determine whether result type of dereference should be ReferenceType or value type.
	129	bool referencesPermissable() {
	130	return ! referencesEliminated;
	131	}
	132
[b1ccdfd]	133	void convertLvalue( std::list< Declaration* > & translationUnit ) {
[1d776fd]	134	PassVisitor<ReferenceConversions> refCvt;
	135	PassVisitor<ReferenceTypeElimination> elim;
	136	PassVisitor<GeneralizedLvalue> genLval;
	137	PassVisitor<FixIntrinsicArgs> fixer;
[cb43451]	138	PassVisitor<CollapseAddrDeref> collapser;
[8499c707]	139	PassVisitor<AddrRef> addrRef;
	140	PassVisitor<FixIntrinsicResult> intrinsicResults;
	141	mutateAll( translationUnit, intrinsicResults );
	142	mutateAll( translationUnit, addrRef );
[1d776fd]	143	mutateAll( translationUnit, refCvt );
	144	mutateAll( translationUnit, fixer );
[cb43451]	145	mutateAll( translationUnit, collapser );
[8499c707]	146	mutateAll( translationUnit, genLval );
[8a6cf7e]	147	mutateAll( translationUnit, elim ); // last because other passes need reference types to work
[b0440b7]	148
	149	// from this point forward, no other pass should create reference types.
	150	referencesEliminated = true;
[01aeade]	151	}
	152
[acd7c5dd]	153	Expression * generalizedLvalue( Expression * expr ) {
[9236060]	154	PassVisitor<GeneralizedLvalue> genLval;
[acd7c5dd]	155	return expr->acceptMutator( genLval );
	156	}
	157
[01aeade]	158	namespace {
[85b2300]	159	// true for intrinsic function calls that return an lvalue in C
[1d776fd]	160	bool isIntrinsicReference( Expression * expr ) {
[85b2300]	161	// known intrinsic-reference prelude functions
	162	static std::set<std::string> lvalueFunctions = { "*?", "?[?]" };
[8a6cf7e]	163	if ( UntypedExpr * untyped = dynamic_cast< UntypedExpr * >( expr ) ) {
	164	std::string fname = InitTweak::getFunctionName( untyped );
[85b2300]	165	return lvalueFunctions.count(fname);
[1d776fd]	166	} else if ( ApplicationExpr * appExpr = dynamic_cast< ApplicationExpr * > ( expr ) ) {
	167	if ( DeclarationWithType * func = InitTweak::getFunction( appExpr ) ) {
[85b2300]	168	return func->linkage == LinkageSpec::Intrinsic && lvalueFunctions.count(func->name);
[1d776fd]	169	}
[ce8c12f]	170	}
[1d776fd]	171	return false;
[ce8c12f]	172	}
	173
[8499c707]	174	Expression * FixIntrinsicResult::postmutate( ApplicationExpr * appExpr ) {
[78cdb06]	175	if ( skip != SkipInProgress && isIntrinsicReference( appExpr ) ) {
[8499c707]	176	// eliminate reference types from intrinsic applications - now they return lvalues
[c1ec14f]	177	ReferenceType * result = strict_dynamic_cast< ReferenceType * >( appExpr->result );
	178	appExpr->result = result->base->clone();
[9aaac6e9]	179	if ( ! inIntrinsic ) {
	180	// when not in an intrinsic function, add a cast to
	181	// don't add cast when in an intrinsic function, since they already have the cast
	182	Expression * ret = new CastExpr( appExpr, result );
[b1ccdfd]	183	std::swap( ret->env, appExpr->env );
[9aaac6e9]	184	return ret;
	185	}
	186	delete result;
[8499c707]	187	}
	188	return appExpr;
	189	}
	190
[9aaac6e9]	191	void FixIntrinsicResult::premutate( FunctionDecl * funcDecl ) {
	192	GuardValue( inIntrinsic );
[c1ec14f]	193	inIntrinsic = funcDecl->linkage == LinkageSpec::Intrinsic;
[9aaac6e9]	194	}
	195
[1d776fd]	196	Expression * FixIntrinsicArgs::postmutate( ApplicationExpr * appExpr ) {
[9a34b5a]	197	// intrinsic functions don't really take reference-typed parameters, so they require an implicit dereference on their arguments.
[1d776fd]	198	if ( DeclarationWithType * function = InitTweak::getFunction( appExpr ) ) {
[d335627]	199	FunctionType * ftype = GenPoly::getFunctionType( function->get_type() );
	200	assertf( ftype, "Function declaration does not have function type." );
	201	// can be of differing lengths only when function is variadic
[b1ccdfd]	202	assertf( ftype->parameters.size() == appExpr->args.size() \|\| ftype->isVarArgs, "ApplicationExpr args do not match formal parameter type." );
[b0440b7]	203
	204
[d335627]	205	unsigned int i = 0;
[b1ccdfd]	206	const unsigned int end = ftype->parameters.size();
[0b73f0c]	207
	208	/// The for loop may eagerly dereference the iterators and fail on empty lists
	209	if(i == end) { return appExpr; }
[b1ccdfd]	210	for ( auto p : unsafe_group_iterate( appExpr->args, ftype->parameters ) ) {
[d335627]	211	Expression *& arg = std::get<0>( p );
	212	Type * formal = std::get<1>( p )->get_type();
	213	PRINT(
	214	std::cerr << "pair<0>: " << arg << std::endl;
[a9b1b0c]	215	std::cerr << " -- " << arg->result << std::endl;
[d335627]	216	std::cerr << "pair<1>: " << formal << std::endl;
	217	)
	218	if ( dynamic_cast<ReferenceType*>( formal ) ) {
[a9b1b0c]	219	PRINT(
	220	std::cerr << "===formal is reference" << std::endl;
	221	)
	222	// TODO: it's likely that the second condition should be ... && ! isIntrinsicReference( arg ), but this requires investigation.
[207b496]	223
[85b2300]	224	if ( function->linkage != LinkageSpec::Intrinsic && isIntrinsicReference( arg ) ) {
[207b496]	225	// needed for definition of prelude functions, etc.
[a9b1b0c]	226	// if argument is dereference or array subscript, the result isn't REALLY a reference, but non-intrinsic functions expect a reference: take address
[a3323db1]	227
	228	// NOTE: previously, this condition fixed
	229	// void f(int *&);
	230	// int & x = ...;
	231	// f(&x);
	232	// But now this is taken care of by a reference cast added by AddrRef. Need to find a new
	233	// example or remove this branch.
[207b496]	234
[a9b1b0c]	235	PRINT(
	236	std::cerr << "===is intrinsic arg in non-intrinsic call - adding address" << std::endl;
	237	)
	238	arg = new AddressExpr( arg );
[da7fe39]	239	// } else if ( function->get_linkage() == LinkageSpec::Intrinsic && InitTweak::getPointerBase( arg->result ) ) {
[85b2300]	240	} else if ( function->linkage == LinkageSpec::Intrinsic && arg->result->referenceDepth() != 0 ) {
[a9b1b0c]	241	// argument is a 'real' reference, but function expects a C lvalue: add a dereference to the reference-typed argument
	242	PRINT(
	243	std::cerr << "===is non-intrinsic arg in intrinsic call - adding deref to arg" << std::endl;
	244	)
[b1ccdfd]	245	Type * baseType = InitTweak::getPointerBase( arg->result );
	246	assertf( baseType, "parameter is reference, arg must be pointer or reference: %s", toString( arg->result ).c_str() );
[d335627]	247	PointerType * ptrType = new PointerType( Type::Qualifiers(), baseType->clone() );
[b1ccdfd]	248	delete arg->result;
[207b496]	249	arg->result = ptrType;
[d335627]	250	arg = mkDeref( arg );
[207b496]	251	// assertf( arg->result->referenceDepth() == 0, "Reference types should have been eliminated from intrinsic function calls, but weren't: %s", toCString( arg->result ) );
[1d776fd]	252	}
	253	}
[d335627]	254	++i;
[aaeacf4]	255	if (i == end) break;
[baba5d8]	256	}
[1d776fd]	257	}
	258	return appExpr;
[01aeade]	259	}
	260
[8499c707]	261	// idea: &&&E: get outer &, inner &
[a3323db1]	262	// at inner &, record depth D of reference type of argument of &
[8499c707]	263	// at outer &, add D derefs.
[a3323db1]	264	void AddrRef::handleNonAddr( Expression * ) {
	265	// non-address-of: reset status variables:
	266	// * current expr is NOT the first address-of expr in an address-of chain
	267	// * next seen address-of expr IS the first in the chain.
[8499c707]	268	GuardValue( current );
	269	GuardValue( first );
	270	current = false;
	271	first = true;
	272	}
	273
[a3323db1]	274	void AddrRef::premutate( Expression * expr ) {
	275	handleNonAddr( expr );
	276	GuardValue( addCast );
	277	addCast = false;
	278	}
	279
[8135d4c]	280	void AddrRef::premutate( AddressExpr * ) {
[8499c707]	281	GuardValue( current );
	282	GuardValue( first );
[a3323db1]	283	current = first; // is this the first address-of in the chain?
	284	first = false; // from here out, no longer possible for next address-of to be first in chain
	285	if ( current ) { // this is the outermost address-of in a chain
[8499c707]	286	GuardValue( refDepth );
[a3323db1]	287	refDepth = 0; // set depth to 0 so that postmutate can find the innermost address-of easily
[8499c707]	288	}
	289	}
	290
	291	Expression * AddrRef::postmutate( AddressExpr * addrExpr ) {
[f74eb47]	292	PRINT( std::cerr << "addr ref at " << addrExpr << std::endl; )
[8499c707]	293	if ( refDepth == 0 ) {
[f74eb47]	294	PRINT( std::cerr << "depth 0, get new depth..." << std::endl; )
[a3323db1]	295	// this is the innermost address-of in a chain, record depth D
[b1ccdfd]	296	if ( ! isIntrinsicReference( addrExpr->arg ) ) {
[8499c707]	297	// try to avoid ?[?]
[a3323db1]	298	// xxx - is this condition still necessary? intrinsicReferences should have a cast around them at this point, so I don't think this condition ever fires.
[b1ccdfd]	299	refDepth = addrExpr->arg->result->referenceDepth();
[f74eb47]	300	PRINT( std::cerr << "arg not intrinsic reference, new depth is: " << refDepth << std::endl; )
[a3323db1]	301	} else {
	302	assertf( false, "AddrRef : address-of should not have intrinsic reference argument: %s", toCString( addrExpr->arg ) );
[8499c707]	303	}
	304	}
[a3323db1]	305	if ( current ) { // this is the outermost address-of in a chain
[f74eb47]	306	PRINT( std::cerr << "current, depth is: " << refDepth << std::endl; )
[8499c707]	307	Expression * ret = addrExpr;
	308	while ( refDepth ) {
[a3323db1]	309	// add one dereference for each
[8499c707]	310	ret = mkDeref( ret );
	311	refDepth--;
	312	}
[a3323db1]	313
[57acae0]	314	// if addrExpr depth is 0, then the result is a pointer because the arg was depth 1 and not lvalue.
	315	// This means the dereference result is not a reference, is lvalue, and one less pointer depth than
	316	// the addrExpr. Thus the cast is meaningless.
	317	// TODO: One thing to double check is whether it is possible for the types to differ outside of the single
	318	// pointer level (i.e. can the base type of addrExpr differ from the type of addrExpr-arg?).
	319	// If so then the cast might need to be added, conditional on a more sophisticated check.
	320	if ( addCast && addrExpr->result->referenceDepth() != 0 ) {
	321	PRINT( std::cerr << "adding cast to " << addrExpr->result << std::endl; )
[a3323db1]	322	return new CastExpr( ret, addrExpr->result->clone() );
	323	}
[8499c707]	324	return ret;
	325	}
[f74eb47]	326	PRINT( std::cerr << "not current..." << std::endl; )
[8499c707]	327	return addrExpr;
	328	}
	329
[a3323db1]	330	void AddrRef::premutate( ApplicationExpr * appExpr ) {
	331	visit_children = false;
	332	GuardValue( addCast );
	333	handleNonAddr( appExpr );
	334	for ( Expression *& arg : appExpr->args ) {
	335	// each argument with address-of requires a cast
	336	addCast = true;
	337	arg = arg->acceptMutator( *visitor );
	338	}
	339	}
	340
	341	void AddrRef::premutate( SingleInit * ) {
	342	GuardValue( addCast );
	343	// each initialization context with address-of requires a cast
	344	addCast = true;
	345	}
	346
	347
[8a6cf7e]	348	Expression * ReferenceConversions::postmutate( AddressExpr * addrExpr ) {
	349	// Inner expression may have been lvalue to reference conversion, which becomes an address expression.
	350	// In this case, remove the outer address expression and return the argument.
	351	// TODO: It's possible that this might catch too much and require a more sophisticated check.
	352	return addrExpr;
	353	}
	354
[1d776fd]	355	Expression * ReferenceConversions::postmutate( CastExpr * castExpr ) {
[9a34b5a]	356	// xxx - is it possible to convert directly between reference types with a different base? E.g.,
	357	// int x;
	358	// (double&)x;
	359	// At the moment, I am working off of the assumption that this is illegal, thus the cast becomes redundant
	360	// after this pass, so trash the cast altogether. If that changes, care must be taken to insert the correct
	361	// pointer casts in the right places.
	362
[a4d188f]	363	// Note: reference depth difference is the determining factor in what code is run, rather than whether something is
	364	// reference type or not, since conversion still needs to occur when both types are references that differ in depth.
[31cb252]	365
	366	Type * destType = castExpr->result;
	367	Type * srcType = castExpr->arg->result;
[c9c9ac4f]	368	assertf( destType, "Cast to no type in: %s", toCString( castExpr ) );
	369	assertf( srcType, "Cast from no type in: %s", toCString( castExpr ) );
[31cb252]	370	int depth1 = destType->referenceDepth();
	371	int depth2 = srcType->referenceDepth();
	372	int diff = depth1 - depth2;
	373
[2d80111]	374	if ( diff > 0 && ! castExpr->arg->get_lvalue() ) {
[31cb252]	375	// rvalue to reference conversion -- introduce temporary
	376	// know that reference depth of cast argument is 0, need to introduce n temporaries for reference depth of n, e.g.
	377	// (int &&&)3;
	378	// becomes
	379	// int __ref_tmp_0 = 3;
	380	// int & __ref_tmp_1 = _&_ref_tmp_0;
	381	// int && __ref_tmp_2 = &__ref_tmp_1;
	382	// &__ref_tmp_2;
[453b586]	383	// the last & comes from the remaining reference conversion code
[2348881]	384	SemanticWarning( castExpr->arg->location, Warning::RvalueToReferenceConversion, toCString( castExpr->arg ) );
[31cb252]	385
	386	static UniqueName tempNamer( "__ref_tmp_" );
	387	ObjectDecl * temp = ObjectDecl::newObject( tempNamer.newName(), castExpr->arg->result->clone(), new SingleInit( castExpr->arg ) );
	388	PRINT( std::cerr << "made temp: " << temp << std::endl; )
	389	stmtsToAddBefore.push_back( new DeclStmt( temp ) );
[a4d188f]	390	for ( int i = 0; i < depth1-1; i++ ) { // xxx - maybe this should be diff-1? check how this works with reference type for srcType
[31cb252]	391	ObjectDecl * newTemp = ObjectDecl::newObject( tempNamer.newName(), new ReferenceType( Type::Qualifiers(), temp->type->clone() ), new SingleInit( new AddressExpr( new VariableExpr( temp ) ) ) );
	392	PRINT( std::cerr << "made temp" << i << ": " << newTemp << std::endl; )
	393	stmtsToAddBefore.push_back( new DeclStmt( newTemp ) );
	394	temp = newTemp;
	395	}
	396	// update diff so that remaining code works out correctly
	397	castExpr->arg = new VariableExpr( temp );
	398	PRINT( std::cerr << "update cast to: " << castExpr << std::endl; )
	399	srcType = castExpr->arg->result;
	400	depth2 = srcType->referenceDepth();
	401	diff = depth1 - depth2;
	402	assert( diff == 1 );
	403	}
[fc56cdbf]	404
[a4d188f]	405	// handle conversion between different depths
[31cb252]	406	PRINT (
	407	if ( depth1 \|\| depth2 ) {
	408	std::cerr << "destType: " << destType << " / srcType: " << srcType << std::endl;
	409	std::cerr << "depth: " << depth1 << " / " << depth2 << std::endl;
	410	}
	411	)
	412	if ( diff > 0 ) {
	413	// conversion to type with more depth (e.g. int & -> int &&): add address-of for each level of difference
	414	Expression * ret = castExpr->arg;
	415	for ( int i = 0; i < diff; ++i ) {
	416	ret = new AddressExpr( ret );
	417	}
[2d80111]	418	if ( castExpr->arg->get_lvalue() && ! ResolvExpr::typesCompatible( srcType, strict_dynamic_cast<ReferenceType *>( destType )->base, SymTab::Indexer() ) ) {
[31cb252]	419	// must keep cast if cast-to type is different from the actual type
	420	castExpr->arg = ret;
[1d776fd]	421	return castExpr;
	422	}
[31cb252]	423	ret->env = castExpr->env;
	424	delete ret->result;
	425	ret->result = castExpr->result;
	426	castExpr->env = nullptr;
	427	castExpr->arg = nullptr;
	428	castExpr->result = nullptr;
	429	delete castExpr;
	430	return ret;
	431	} else if ( diff < 0 ) {
	432	// conversion to type with less depth (e.g. int && -> int &): add dereferences for each level of difference
	433	diff = -diff; // care only about magnitude now
[0690350]	434	Expression * ret = castExpr->arg;
[31cb252]	435	for ( int i = 0; i < diff; ++i ) {
[9191a8e]	436	ret = mkDeref( ret );
[ba89e9b7]	437	// xxx - try removing one reference here? actually, looks like mkDeref already does this, so more closely look at the types generated.
[9191a8e]	438	}
[31cb252]	439	if ( ! ResolvExpr::typesCompatibleIgnoreQualifiers( destType->stripReferences(), srcType->stripReferences(), SymTab::Indexer() ) ) {
[8a6cf7e]	440	// must keep cast if types are different
[0690350]	441	castExpr->arg = ret;
[31cb252]	442	return castExpr;
[8a6cf7e]	443	}
[31cb252]	444	ret->env = castExpr->env;
	445	delete ret->result;
	446	ret->result = castExpr->result;
[b4f8808]	447	assert( ret->get_lvalue() ); // ensure result is lvalue
[31cb252]	448	castExpr->env = nullptr;
	449	castExpr->arg = nullptr;
	450	castExpr->result = nullptr;
	451	delete castExpr;
[9191a8e]	452	return ret;
[31cb252]	453	} else {
	454	assert( diff == 0 );
	455	// conversion between references of the same depth
[70a5acf]	456	if ( ResolvExpr::typesCompatible( castExpr->result, castExpr->arg->result, SymTab::Indexer() ) && castExpr->isGenerated ) {
	457	// Remove useless generated casts
	458	PRINT(
	459	std::cerr << "types are compatible, removing cast: " << castExpr << std::endl;
	460	std::cerr << "-- " << castExpr->result << std::endl;
	461	std::cerr << "-- " << castExpr->arg->result << std::endl;
	462	)
	463	Expression * ret = castExpr->arg;
	464	castExpr->arg = nullptr;
	465	std::swap( castExpr->env, ret->env );
	466	delete castExpr;
	467	return ret;
	468	}
[31cb252]	469	return castExpr;
[1d776fd]	470	}
[01aeade]	471	}
[b6fd751]	472
[1d776fd]	473	Type * ReferenceTypeElimination::postmutate( ReferenceType * refType ) {
[b1ccdfd]	474	Type * base = refType->base;
[8a6cf7e]	475	Type::Qualifiers qualifiers = refType->get_qualifiers();
[b1ccdfd]	476	refType->base = nullptr;
[1d776fd]	477	delete refType;
[8a6cf7e]	478	return new PointerType( qualifiers, base );
[ce8c12f]	479	}
	480
[acd7c5dd]	481	template<typename Func>
	482	Expression * GeneralizedLvalue::applyTransformation( Expression * expr, Expression * arg, Func mkExpr ) {
	483	if ( CommaExpr * commaExpr = dynamic_cast< CommaExpr * >( arg ) ) {
[b1ccdfd]	484	Expression * arg1 = commaExpr->arg1->clone();
	485	Expression * arg2 = commaExpr->arg2->clone();
[9236060]	486	Expression * ret = new CommaExpr( arg1, mkExpr( arg2 )->acceptMutator( *visitor ) );
[b1ccdfd]	487	ret->env = expr->env;
	488	expr->env = nullptr;
[acd7c5dd]	489	delete expr;
[8499c707]	490	return ret;
[acd7c5dd]	491	} else if ( ConditionalExpr * condExpr = dynamic_cast< ConditionalExpr * >( arg ) ) {
[b1ccdfd]	492	Expression * arg1 = condExpr->arg1->clone();
	493	Expression * arg2 = condExpr->arg2->clone();
	494	Expression * arg3 = condExpr->arg3->clone();
[9236060]	495	ConditionalExpr * ret = new ConditionalExpr( arg1, mkExpr( arg2 )->acceptMutator( visitor ), mkExpr( arg3 )->acceptMutator( visitor ) );
[b1ccdfd]	496	ret->env = expr->env;
	497	expr->env = nullptr;
[acd7c5dd]	498	delete expr;
	499
	500	// conditional expr type may not be either of the argument types, need to unify
	501	using namespace ResolvExpr;
	502	Type* commonType = nullptr;
	503	TypeEnvironment newEnv;
	504	AssertionSet needAssertions, haveAssertions;
	505	OpenVarSet openVars;
[b1ccdfd]	506	unify( ret->arg2->result, ret->arg3->result, newEnv, needAssertions, haveAssertions, openVars, SymTab::Indexer(), commonType );
	507	ret->result = commonType ? commonType : ret->arg2->result->clone();
[8499c707]	508	return ret;
[b6fd751]	509	}
[acd7c5dd]	510	return expr;
	511	}
	512
[9236060]	513	Expression * GeneralizedLvalue::postmutate( MemberExpr * memExpr ) {
[b1ccdfd]	514	return applyTransformation( memExpr, memExpr->aggregate, [=]( Expression * aggr ) { return new MemberExpr( memExpr->member, aggr ); } );
[acd7c5dd]	515	}
	516
[9236060]	517	Expression * GeneralizedLvalue::postmutate( AddressExpr * addrExpr ) {
[b1ccdfd]	518	return applyTransformation( addrExpr, addrExpr->arg, []( Expression * arg ) { return new AddressExpr( arg ); } );
[b6fd751]	519	}
[cb43451]	520
[8499c707]	521	Expression * CollapseAddrDeref::postmutate( AddressExpr * addrExpr ) {
[b1ccdfd]	522	Expression * arg = addrExpr->arg;
[cb43451]	523	if ( isIntrinsicReference( arg ) ) {
	524	std::string fname = InitTweak::getFunctionName( arg );
	525	if ( fname == "*?" ) {
	526	Expression *& arg0 = InitTweak::getCallArg( arg, 0 );
	527	Expression * ret = arg0;
[b1ccdfd]	528	ret->set_env( addrExpr->env );
[cb43451]	529	arg0 = nullptr;
[b1ccdfd]	530	addrExpr->env = nullptr;
[8499c707]	531	delete addrExpr;
[cb43451]	532	return ret;
	533	}
[bf7b6015]	534	} else if ( CastExpr * castExpr = dynamic_cast< CastExpr * > ( arg ) ) {
	535	// need to move cast to pointer type out a level since address of pointer
	536	// is not valid C code (can be introduced in prior passes, e.g., InstantiateGeneric)
	537	if ( InitTweak::getPointerBase( castExpr->result ) ) {
	538	addrExpr->arg = castExpr->arg;
	539	castExpr->arg = addrExpr;
	540	castExpr->result = new PointerType( Type::Qualifiers(), castExpr->result );
	541	return castExpr;
	542	}
[cb43451]	543	}
[8499c707]	544	return addrExpr;
[cb43451]	545	}
	546
	547	Expression * CollapseAddrDeref::postmutate( ApplicationExpr * appExpr ) {
	548	if ( isIntrinsicReference( appExpr ) ) {
	549	std::string fname = InitTweak::getFunctionName( appExpr );
	550	if ( fname == "*?" ) {
	551	Expression * arg = InitTweak::getCallArg( appExpr, 0 );
	552	// xxx - this isn't right, because it can remove casts that should be there...
	553	// while ( CastExpr * castExpr = dynamic_cast< CastExpr * >( arg ) ) {
	554	// arg = castExpr->get_arg();
	555	// }
	556	if ( AddressExpr * addrExpr = dynamic_cast< AddressExpr * >( arg ) ) {
[b1ccdfd]	557	Expression * ret = addrExpr->arg;
	558	ret->env = appExpr->env;
	559	addrExpr->arg = nullptr;
	560	appExpr->env = nullptr;
[cb43451]	561	delete appExpr;
	562	return ret;
	563	}
	564	}
	565	}
	566	return appExpr;
	567	}
[01aeade]	568	} // namespace
[51b7345]	569	} // namespace GenPoly
[01aeade]	570
[51587aa]	571	// Local Variables: //
	572	// tab-width: 4 //
	573	// mode: c++ //
	574	// compile-command: "make install" //
	575	// End: //

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