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source: src/GenPoly/Lvalue.cc @ 2d80111

ADTarm-ehast-experimentalenumforall-pointer-decayjacob/cs343-translationjenkins-sandboxnew-astnew-ast-unique-exprpthread-emulationqualifiedEnum

Last change on this file since 2d80111 was 2d80111, checked in by Andrew Beach <ajbeach@…>, 5 years ago
Lvalue is checked through Expression::get_lvalue. Only three other places use Type::get_lvalue directly now: CodeGen/GenType?, ResolvExpr/ConversionCost? & SynTree/TopLvalue?.
Property mode set to `100644`
File size: 23.3 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
[615a096]	12	// Last Modified On : Fri Mar 17 09:11:18 2017
	13	// Update Count : 5
[51587aa]	14	//
[51b7345]	15
[e3e16bc]	16	#include <cassert> // for strict_dynamic_cast
[08fc48f]	17	#include <string> // for string
[51b7345]	18
[8135d4c]	19	#include "Common/PassVisitor.h"
[08fc48f]	20	#include "GenPoly.h" // for isPolyType
[51b7345]	21	#include "Lvalue.h"
	22
[2bfc6b2]	23	#include "InitTweak/InitTweak.h"
[08fc48f]	24	#include "Parser/LinkageSpec.h" // for Spec, isBuiltin, Intrinsic
	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
	29	#include "SynTree/Declaration.h" // for Declaration, FunctionDecl
	30	#include "SynTree/Expression.h" // for Expression, ConditionalExpr
	31	#include "SynTree/Mutator.h" // for mutateAll, Mutator
	32	#include "SynTree/Statement.h" // for ReturnStmt, Statement (ptr o...
	33	#include "SynTree/Type.h" // for PointerType, Type, FunctionType
	34	#include "SynTree/Visitor.h" // for Visitor, acceptAll
[2bfc6b2]	35	#include "Validate/FindSpecialDecls.h" // for dereferenceOperator
[1d776fd]	36
[cb43451]	37	#if 0
	38	#define PRINT(x) x
	39	#else
	40	#define PRINT(x)
	41	#endif
	42
[51b7345]	43	namespace GenPoly {
[01aeade]	44	namespace {
[9a34b5a]	45	// TODO: fold this into the general createDeref function??
	46	Expression * mkDeref( Expression * arg ) {
[2bfc6b2]	47	if ( Validate::dereferenceOperator ) {
[a9b1b0c]	48	// 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]	49	VariableExpr * deref = new VariableExpr( Validate::dereferenceOperator );
[0690350]	50	deref->result = new PointerType( Type::Qualifiers(), deref->result );
	51	Type * base = InitTweak::getPointerBase( arg->result );
	52	assertf( base, "expected pointer type in dereference (type was %s)", toString( arg->result ).c_str() );
[9a34b5a]	53	ApplicationExpr * ret = new ApplicationExpr( deref, { arg } );
[0690350]	54	delete ret->result;
	55	ret->result = base->clone();
	56	ret->result->set_lvalue( true );
[9a34b5a]	57	return ret;
	58	} else {
	59	return UntypedExpr::createDeref( arg );
	60	}
	61	}
	62
[31cb252]	63	struct ReferenceConversions final : public WithStmtsToAdd {
[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 {
[8499c707]	74	Expression * postmutate( ApplicationExpr * appExpr );
[9aaac6e9]	75	void premutate( FunctionDecl * funcDecl );
	76	bool inIntrinsic = false;
[8499c707]	77	};
[1d776fd]	78
	79	/// Replace reference types with pointer types
	80	struct ReferenceTypeElimination final {
	81	Type * postmutate( ReferenceType * refType );
[01aeade]	82	};
[b6fd751]	83
	84	/// GCC-like Generalized Lvalues (which have since been removed from GCC)
	85	/// https://gcc.gnu.org/onlinedocs/gcc-3.4.6/gcc/Lvalues.html#Lvalues
	86	/// Replaces &(a,b) with (a, &b), &(a ? b : c) with (a ? &b : &c)
[d335627]	87	struct GeneralizedLvalue final : public WithVisitorRef<GeneralizedLvalue> {
[1d776fd]	88	Expression * postmutate( AddressExpr * addressExpr );
[9236060]	89	Expression * postmutate( MemberExpr * memExpr );
[acd7c5dd]	90
	91	template<typename Func>
	92	Expression * applyTransformation( Expression * expr, Expression * arg, Func mkExpr );
[b6fd751]	93	};
[cb43451]	94
	95	/// Removes redundant &/& pattern that this pass can generate
	96	struct CollapseAddrDeref final {
	97	Expression * postmutate( AddressExpr * addressExpr );
	98	Expression * postmutate( ApplicationExpr * appExpr );
	99	};
[8499c707]	100
[a3323db1]	101	struct AddrRef final : public WithGuards, public WithVisitorRef<AddrRef>, public WithShortCircuiting {
[8499c707]	102	void premutate( AddressExpr * addrExpr );
	103	Expression * postmutate( AddressExpr * addrExpr );
	104	void premutate( Expression * expr );
[a3323db1]	105	void premutate( ApplicationExpr * appExpr );
	106	void premutate( SingleInit * init );
	107
	108	void handleNonAddr( Expression * );
[8499c707]	109
	110	bool first = true;
	111	bool current = false;
	112	int refDepth = 0;
[a3323db1]	113	bool addCast = false;
[8499c707]	114	};
[01aeade]	115	} // namespace
	116
[b0440b7]	117	static bool referencesEliminated = false;
	118	// used by UntypedExpr::createDeref to determine whether result type of dereference should be ReferenceType or value type.
	119	bool referencesPermissable() {
	120	return ! referencesEliminated;
	121	}
	122
[b1ccdfd]	123	void convertLvalue( std::list< Declaration* > & translationUnit ) {
[1d776fd]	124	PassVisitor<ReferenceConversions> refCvt;
	125	PassVisitor<ReferenceTypeElimination> elim;
	126	PassVisitor<GeneralizedLvalue> genLval;
	127	PassVisitor<FixIntrinsicArgs> fixer;
[cb43451]	128	PassVisitor<CollapseAddrDeref> collapser;
[8499c707]	129	PassVisitor<AddrRef> addrRef;
	130	PassVisitor<FixIntrinsicResult> intrinsicResults;
	131	mutateAll( translationUnit, intrinsicResults );
	132	mutateAll( translationUnit, addrRef );
[1d776fd]	133	mutateAll( translationUnit, refCvt );
	134	mutateAll( translationUnit, fixer );
[cb43451]	135	mutateAll( translationUnit, collapser );
[8499c707]	136	mutateAll( translationUnit, genLval );
[8a6cf7e]	137	mutateAll( translationUnit, elim ); // last because other passes need reference types to work
[b0440b7]	138
	139	// from this point forward, no other pass should create reference types.
	140	referencesEliminated = true;
[01aeade]	141	}
	142
[acd7c5dd]	143	Expression * generalizedLvalue( Expression * expr ) {
[9236060]	144	PassVisitor<GeneralizedLvalue> genLval;
[acd7c5dd]	145	return expr->acceptMutator( genLval );
	146	}
	147
[01aeade]	148	namespace {
[85b2300]	149	// true for intrinsic function calls that return an lvalue in C
[1d776fd]	150	bool isIntrinsicReference( Expression * expr ) {
[85b2300]	151	// known intrinsic-reference prelude functions
	152	static std::set<std::string> lvalueFunctions = { "*?", "?[?]" };
[8a6cf7e]	153	if ( UntypedExpr * untyped = dynamic_cast< UntypedExpr * >( expr ) ) {
	154	std::string fname = InitTweak::getFunctionName( untyped );
[85b2300]	155	return lvalueFunctions.count(fname);
[1d776fd]	156	} else if ( ApplicationExpr * appExpr = dynamic_cast< ApplicationExpr * > ( expr ) ) {
	157	if ( DeclarationWithType * func = InitTweak::getFunction( appExpr ) ) {
[85b2300]	158	return func->linkage == LinkageSpec::Intrinsic && lvalueFunctions.count(func->name);
[1d776fd]	159	}
[ce8c12f]	160	}
[1d776fd]	161	return false;
[ce8c12f]	162	}
	163
[8499c707]	164	Expression * FixIntrinsicResult::postmutate( ApplicationExpr * appExpr ) {
	165	if ( isIntrinsicReference( appExpr ) ) {
	166	// eliminate reference types from intrinsic applications - now they return lvalues
[c1ec14f]	167	ReferenceType * result = strict_dynamic_cast< ReferenceType * >( appExpr->result );
	168	appExpr->result = result->base->clone();
[b1ccdfd]	169	appExpr->result->set_lvalue( true );
[9aaac6e9]	170	if ( ! inIntrinsic ) {
	171	// when not in an intrinsic function, add a cast to
	172	// don't add cast when in an intrinsic function, since they already have the cast
	173	Expression * ret = new CastExpr( appExpr, result );
[b1ccdfd]	174	std::swap( ret->env, appExpr->env );
[9aaac6e9]	175	return ret;
	176	}
	177	delete result;
[8499c707]	178	}
	179	return appExpr;
	180	}
	181
[9aaac6e9]	182	void FixIntrinsicResult::premutate( FunctionDecl * funcDecl ) {
	183	GuardValue( inIntrinsic );
[c1ec14f]	184	inIntrinsic = funcDecl->linkage == LinkageSpec::Intrinsic;
[9aaac6e9]	185	}
	186
[1d776fd]	187	Expression * FixIntrinsicArgs::postmutate( ApplicationExpr * appExpr ) {
[9a34b5a]	188	// intrinsic functions don't really take reference-typed parameters, so they require an implicit dereference on their arguments.
[1d776fd]	189	if ( DeclarationWithType * function = InitTweak::getFunction( appExpr ) ) {
[d335627]	190	FunctionType * ftype = GenPoly::getFunctionType( function->get_type() );
	191	assertf( ftype, "Function declaration does not have function type." );
	192	// can be of differing lengths only when function is variadic
[b1ccdfd]	193	assertf( ftype->parameters.size() == appExpr->args.size() \|\| ftype->isVarArgs, "ApplicationExpr args do not match formal parameter type." );
[b0440b7]	194
	195
[d335627]	196	unsigned int i = 0;
[b1ccdfd]	197	const unsigned int end = ftype->parameters.size();
[0b73f0c]	198
	199	/// The for loop may eagerly dereference the iterators and fail on empty lists
	200	if(i == end) { return appExpr; }
[b1ccdfd]	201	for ( auto p : unsafe_group_iterate( appExpr->args, ftype->parameters ) ) {
[d335627]	202	Expression *& arg = std::get<0>( p );
	203	Type * formal = std::get<1>( p )->get_type();
	204	PRINT(
	205	std::cerr << "pair<0>: " << arg << std::endl;
[a9b1b0c]	206	std::cerr << " -- " << arg->result << std::endl;
[d335627]	207	std::cerr << "pair<1>: " << formal << std::endl;
	208	)
	209	if ( dynamic_cast<ReferenceType*>( formal ) ) {
[a9b1b0c]	210	PRINT(
	211	std::cerr << "===formal is reference" << std::endl;
	212	)
	213	// TODO: it's likely that the second condition should be ... && ! isIntrinsicReference( arg ), but this requires investigation.
[207b496]	214
[85b2300]	215	if ( function->linkage != LinkageSpec::Intrinsic && isIntrinsicReference( arg ) ) {
[207b496]	216	// needed for definition of prelude functions, etc.
[a9b1b0c]	217	// if argument is dereference or array subscript, the result isn't REALLY a reference, but non-intrinsic functions expect a reference: take address
[a3323db1]	218
	219	// NOTE: previously, this condition fixed
	220	// void f(int *&);
	221	// int & x = ...;
	222	// f(&x);
	223	// But now this is taken care of by a reference cast added by AddrRef. Need to find a new
	224	// example or remove this branch.
[207b496]	225
[a9b1b0c]	226	PRINT(
	227	std::cerr << "===is intrinsic arg in non-intrinsic call - adding address" << std::endl;
	228	)
	229	arg = new AddressExpr( arg );
[da7fe39]	230	// } else if ( function->get_linkage() == LinkageSpec::Intrinsic && InitTweak::getPointerBase( arg->result ) ) {
[85b2300]	231	} else if ( function->linkage == LinkageSpec::Intrinsic && arg->result->referenceDepth() != 0 ) {
[a9b1b0c]	232	// argument is a 'real' reference, but function expects a C lvalue: add a dereference to the reference-typed argument
	233	PRINT(
	234	std::cerr << "===is non-intrinsic arg in intrinsic call - adding deref to arg" << std::endl;
	235	)
[b1ccdfd]	236	Type * baseType = InitTweak::getPointerBase( arg->result );
	237	assertf( baseType, "parameter is reference, arg must be pointer or reference: %s", toString( arg->result ).c_str() );
[d335627]	238	PointerType * ptrType = new PointerType( Type::Qualifiers(), baseType->clone() );
[b1ccdfd]	239	delete arg->result;
[207b496]	240	arg->result = ptrType;
[d335627]	241	arg = mkDeref( arg );
[207b496]	242	// assertf( arg->result->referenceDepth() == 0, "Reference types should have been eliminated from intrinsic function calls, but weren't: %s", toCString( arg->result ) );
[1d776fd]	243	}
	244	}
[d335627]	245	++i;
[aaeacf4]	246	if (i == end) break;
[baba5d8]	247	}
[1d776fd]	248	}
	249	return appExpr;
[01aeade]	250	}
	251
[8499c707]	252	// idea: &&&E: get outer &, inner &
[a3323db1]	253	// at inner &, record depth D of reference type of argument of &
[8499c707]	254	// at outer &, add D derefs.
[a3323db1]	255	void AddrRef::handleNonAddr( Expression * ) {
	256	// non-address-of: reset status variables:
	257	// * current expr is NOT the first address-of expr in an address-of chain
	258	// * next seen address-of expr IS the first in the chain.
[8499c707]	259	GuardValue( current );
	260	GuardValue( first );
	261	current = false;
	262	first = true;
	263	}
	264
[a3323db1]	265	void AddrRef::premutate( Expression * expr ) {
	266	handleNonAddr( expr );
	267	GuardValue( addCast );
	268	addCast = false;
	269	}
	270
[8135d4c]	271	void AddrRef::premutate( AddressExpr * ) {
[8499c707]	272	GuardValue( current );
	273	GuardValue( first );
[a3323db1]	274	current = first; // is this the first address-of in the chain?
	275	first = false; // from here out, no longer possible for next address-of to be first in chain
	276	if ( current ) { // this is the outermost address-of in a chain
[8499c707]	277	GuardValue( refDepth );
[a3323db1]	278	refDepth = 0; // set depth to 0 so that postmutate can find the innermost address-of easily
[8499c707]	279	}
	280	}
	281
	282	Expression * AddrRef::postmutate( AddressExpr * addrExpr ) {
[f74eb47]	283	PRINT( std::cerr << "addr ref at " << addrExpr << std::endl; )
[8499c707]	284	if ( refDepth == 0 ) {
[f74eb47]	285	PRINT( std::cerr << "depth 0, get new depth..." << std::endl; )
[a3323db1]	286	// this is the innermost address-of in a chain, record depth D
[b1ccdfd]	287	if ( ! isIntrinsicReference( addrExpr->arg ) ) {
[8499c707]	288	// try to avoid ?[?]
[a3323db1]	289	// 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]	290	refDepth = addrExpr->arg->result->referenceDepth();
[f74eb47]	291	PRINT( std::cerr << "arg not intrinsic reference, new depth is: " << refDepth << std::endl; )
[a3323db1]	292	} else {
	293	assertf( false, "AddrRef : address-of should not have intrinsic reference argument: %s", toCString( addrExpr->arg ) );
[8499c707]	294	}
	295	}
[a3323db1]	296	if ( current ) { // this is the outermost address-of in a chain
[f74eb47]	297	PRINT( std::cerr << "current, depth is: " << refDepth << std::endl; )
[8499c707]	298	Expression * ret = addrExpr;
	299	while ( refDepth ) {
[a3323db1]	300	// add one dereference for each
[8499c707]	301	ret = mkDeref( ret );
	302	refDepth--;
	303	}
[a3323db1]	304
[57acae0]	305	// if addrExpr depth is 0, then the result is a pointer because the arg was depth 1 and not lvalue.
	306	// This means the dereference result is not a reference, is lvalue, and one less pointer depth than
	307	// the addrExpr. Thus the cast is meaningless.
	308	// TODO: One thing to double check is whether it is possible for the types to differ outside of the single
	309	// pointer level (i.e. can the base type of addrExpr differ from the type of addrExpr-arg?).
	310	// If so then the cast might need to be added, conditional on a more sophisticated check.
	311	if ( addCast && addrExpr->result->referenceDepth() != 0 ) {
	312	PRINT( std::cerr << "adding cast to " << addrExpr->result << std::endl; )
[a3323db1]	313	return new CastExpr( ret, addrExpr->result->clone() );
	314	}
[8499c707]	315	return ret;
	316	}
[f74eb47]	317	PRINT( std::cerr << "not current..." << std::endl; )
[8499c707]	318	return addrExpr;
	319	}
	320
[a3323db1]	321	void AddrRef::premutate( ApplicationExpr * appExpr ) {
	322	visit_children = false;
	323	GuardValue( addCast );
	324	handleNonAddr( appExpr );
	325	for ( Expression *& arg : appExpr->args ) {
	326	// each argument with address-of requires a cast
	327	addCast = true;
	328	arg = arg->acceptMutator( *visitor );
	329	}
	330	}
	331
	332	void AddrRef::premutate( SingleInit * ) {
	333	GuardValue( addCast );
	334	// each initialization context with address-of requires a cast
	335	addCast = true;
	336	}
	337
	338
[8a6cf7e]	339	Expression * ReferenceConversions::postmutate( AddressExpr * addrExpr ) {
	340	// Inner expression may have been lvalue to reference conversion, which becomes an address expression.
	341	// In this case, remove the outer address expression and return the argument.
	342	// TODO: It's possible that this might catch too much and require a more sophisticated check.
	343	return addrExpr;
	344	}
	345
[1d776fd]	346	Expression * ReferenceConversions::postmutate( CastExpr * castExpr ) {
[9a34b5a]	347	// xxx - is it possible to convert directly between reference types with a different base? E.g.,
	348	// int x;
	349	// (double&)x;
	350	// At the moment, I am working off of the assumption that this is illegal, thus the cast becomes redundant
	351	// after this pass, so trash the cast altogether. If that changes, care must be taken to insert the correct
	352	// pointer casts in the right places.
	353
[a4d188f]	354	// Note: reference depth difference is the determining factor in what code is run, rather than whether something is
	355	// reference type or not, since conversion still needs to occur when both types are references that differ in depth.
[31cb252]	356
	357	Type * destType = castExpr->result;
	358	Type * srcType = castExpr->arg->result;
[c9c9ac4f]	359	assertf( destType, "Cast to no type in: %s", toCString( castExpr ) );
	360	assertf( srcType, "Cast from no type in: %s", toCString( castExpr ) );
[31cb252]	361	int depth1 = destType->referenceDepth();
	362	int depth2 = srcType->referenceDepth();
	363	int diff = depth1 - depth2;
	364
[2d80111]	365	if ( diff > 0 && ! castExpr->arg->get_lvalue() ) {
[31cb252]	366	// rvalue to reference conversion -- introduce temporary
	367	// know that reference depth of cast argument is 0, need to introduce n temporaries for reference depth of n, e.g.
	368	// (int &&&)3;
	369	// becomes
	370	// int __ref_tmp_0 = 3;
	371	// int & __ref_tmp_1 = _&_ref_tmp_0;
	372	// int && __ref_tmp_2 = &__ref_tmp_1;
	373	// &__ref_tmp_2;
[453b586]	374	// the last & comes from the remaining reference conversion code
[2348881]	375	SemanticWarning( castExpr->arg->location, Warning::RvalueToReferenceConversion, toCString( castExpr->arg ) );
[31cb252]	376
	377	static UniqueName tempNamer( "__ref_tmp_" );
	378	ObjectDecl * temp = ObjectDecl::newObject( tempNamer.newName(), castExpr->arg->result->clone(), new SingleInit( castExpr->arg ) );
	379	PRINT( std::cerr << "made temp: " << temp << std::endl; )
	380	stmtsToAddBefore.push_back( new DeclStmt( temp ) );
[a4d188f]	381	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]	382	ObjectDecl * newTemp = ObjectDecl::newObject( tempNamer.newName(), new ReferenceType( Type::Qualifiers(), temp->type->clone() ), new SingleInit( new AddressExpr( new VariableExpr( temp ) ) ) );
	383	PRINT( std::cerr << "made temp" << i << ": " << newTemp << std::endl; )
	384	stmtsToAddBefore.push_back( new DeclStmt( newTemp ) );
	385	temp = newTemp;
	386	}
	387	// update diff so that remaining code works out correctly
	388	castExpr->arg = new VariableExpr( temp );
	389	PRINT( std::cerr << "update cast to: " << castExpr << std::endl; )
	390	srcType = castExpr->arg->result;
	391	depth2 = srcType->referenceDepth();
	392	diff = depth1 - depth2;
	393	assert( diff == 1 );
	394	}
[fc56cdbf]	395
[a4d188f]	396	// handle conversion between different depths
[31cb252]	397	PRINT (
	398	if ( depth1 \|\| depth2 ) {
	399	std::cerr << "destType: " << destType << " / srcType: " << srcType << std::endl;
	400	std::cerr << "depth: " << depth1 << " / " << depth2 << std::endl;
	401	}
	402	)
	403	if ( diff > 0 ) {
	404	// conversion to type with more depth (e.g. int & -> int &&): add address-of for each level of difference
	405	Expression * ret = castExpr->arg;
	406	for ( int i = 0; i < diff; ++i ) {
	407	ret = new AddressExpr( ret );
	408	}
[2d80111]	409	if ( castExpr->arg->get_lvalue() && ! ResolvExpr::typesCompatible( srcType, strict_dynamic_cast<ReferenceType *>( destType )->base, SymTab::Indexer() ) ) {
[31cb252]	410	// must keep cast if cast-to type is different from the actual type
	411	castExpr->arg = ret;
[1d776fd]	412	return castExpr;
	413	}
[31cb252]	414	ret->env = castExpr->env;
	415	delete ret->result;
	416	ret->result = castExpr->result;
	417	castExpr->env = nullptr;
	418	castExpr->arg = nullptr;
	419	castExpr->result = nullptr;
	420	delete castExpr;
	421	return ret;
	422	} else if ( diff < 0 ) {
	423	// conversion to type with less depth (e.g. int && -> int &): add dereferences for each level of difference
	424	diff = -diff; // care only about magnitude now
[0690350]	425	Expression * ret = castExpr->arg;
[31cb252]	426	for ( int i = 0; i < diff; ++i ) {
[9191a8e]	427	ret = mkDeref( ret );
[ba89e9b7]	428	// xxx - try removing one reference here? actually, looks like mkDeref already does this, so more closely look at the types generated.
[9191a8e]	429	}
[31cb252]	430	if ( ! ResolvExpr::typesCompatibleIgnoreQualifiers( destType->stripReferences(), srcType->stripReferences(), SymTab::Indexer() ) ) {
[8a6cf7e]	431	// must keep cast if types are different
[0690350]	432	castExpr->arg = ret;
[31cb252]	433	return castExpr;
[8a6cf7e]	434	}
[31cb252]	435	ret->env = castExpr->env;
	436	delete ret->result;
	437	ret->result = castExpr->result;
	438	ret->result->set_lvalue( true ); // ensure result is lvalue
	439	castExpr->env = nullptr;
	440	castExpr->arg = nullptr;
	441	castExpr->result = nullptr;
	442	delete castExpr;
[9191a8e]	443	return ret;
[31cb252]	444	} else {
	445	assert( diff == 0 );
	446	// conversion between references of the same depth
[70a5acf]	447	if ( ResolvExpr::typesCompatible( castExpr->result, castExpr->arg->result, SymTab::Indexer() ) && castExpr->isGenerated ) {
	448	// Remove useless generated casts
	449	PRINT(
	450	std::cerr << "types are compatible, removing cast: " << castExpr << std::endl;
	451	std::cerr << "-- " << castExpr->result << std::endl;
	452	std::cerr << "-- " << castExpr->arg->result << std::endl;
	453	)
	454	Expression * ret = castExpr->arg;
	455	castExpr->arg = nullptr;
	456	std::swap( castExpr->env, ret->env );
	457	delete castExpr;
	458	return ret;
	459	}
[31cb252]	460	return castExpr;
[1d776fd]	461	}
[01aeade]	462	}
[b6fd751]	463
[1d776fd]	464	Type * ReferenceTypeElimination::postmutate( ReferenceType * refType ) {
[b1ccdfd]	465	Type * base = refType->base;
[8a6cf7e]	466	Type::Qualifiers qualifiers = refType->get_qualifiers();
[b1ccdfd]	467	refType->base = nullptr;
[1d776fd]	468	delete refType;
[8a6cf7e]	469	return new PointerType( qualifiers, base );
[ce8c12f]	470	}
	471
[acd7c5dd]	472	template<typename Func>
	473	Expression * GeneralizedLvalue::applyTransformation( Expression * expr, Expression * arg, Func mkExpr ) {
	474	if ( CommaExpr * commaExpr = dynamic_cast< CommaExpr * >( arg ) ) {
[b1ccdfd]	475	Expression * arg1 = commaExpr->arg1->clone();
	476	Expression * arg2 = commaExpr->arg2->clone();
[9236060]	477	Expression * ret = new CommaExpr( arg1, mkExpr( arg2 )->acceptMutator( *visitor ) );
[b1ccdfd]	478	ret->env = expr->env;
	479	expr->env = nullptr;
[acd7c5dd]	480	delete expr;
[8499c707]	481	return ret;
[acd7c5dd]	482	} else if ( ConditionalExpr * condExpr = dynamic_cast< ConditionalExpr * >( arg ) ) {
[b1ccdfd]	483	Expression * arg1 = condExpr->arg1->clone();
	484	Expression * arg2 = condExpr->arg2->clone();
	485	Expression * arg3 = condExpr->arg3->clone();
[9236060]	486	ConditionalExpr * ret = new ConditionalExpr( arg1, mkExpr( arg2 )->acceptMutator( visitor ), mkExpr( arg3 )->acceptMutator( visitor ) );
[b1ccdfd]	487	ret->env = expr->env;
	488	expr->env = nullptr;
[acd7c5dd]	489	delete expr;
	490
	491	// conditional expr type may not be either of the argument types, need to unify
	492	using namespace ResolvExpr;
	493	Type* commonType = nullptr;
	494	TypeEnvironment newEnv;
	495	AssertionSet needAssertions, haveAssertions;
	496	OpenVarSet openVars;
[b1ccdfd]	497	unify( ret->arg2->result, ret->arg3->result, newEnv, needAssertions, haveAssertions, openVars, SymTab::Indexer(), commonType );
	498	ret->result = commonType ? commonType : ret->arg2->result->clone();
[8499c707]	499	return ret;
[b6fd751]	500	}
[acd7c5dd]	501	return expr;
	502	}
	503
[9236060]	504	Expression * GeneralizedLvalue::postmutate( MemberExpr * memExpr ) {
[b1ccdfd]	505	return applyTransformation( memExpr, memExpr->aggregate, [=]( Expression * aggr ) { return new MemberExpr( memExpr->member, aggr ); } );
[acd7c5dd]	506	}
	507
[9236060]	508	Expression * GeneralizedLvalue::postmutate( AddressExpr * addrExpr ) {
[b1ccdfd]	509	return applyTransformation( addrExpr, addrExpr->arg, []( Expression * arg ) { return new AddressExpr( arg ); } );
[b6fd751]	510	}
[cb43451]	511
[8499c707]	512	Expression * CollapseAddrDeref::postmutate( AddressExpr * addrExpr ) {
[b1ccdfd]	513	Expression * arg = addrExpr->arg;
[cb43451]	514	if ( isIntrinsicReference( arg ) ) {
	515	std::string fname = InitTweak::getFunctionName( arg );
	516	if ( fname == "*?" ) {
	517	Expression *& arg0 = InitTweak::getCallArg( arg, 0 );
	518	Expression * ret = arg0;
[b1ccdfd]	519	ret->set_env( addrExpr->env );
[cb43451]	520	arg0 = nullptr;
[b1ccdfd]	521	addrExpr->env = nullptr;
[8499c707]	522	delete addrExpr;
[cb43451]	523	return ret;
	524	}
[bf7b6015]	525	} else if ( CastExpr * castExpr = dynamic_cast< CastExpr * > ( arg ) ) {
	526	// need to move cast to pointer type out a level since address of pointer
	527	// is not valid C code (can be introduced in prior passes, e.g., InstantiateGeneric)
	528	if ( InitTweak::getPointerBase( castExpr->result ) ) {
	529	addrExpr->arg = castExpr->arg;
	530	castExpr->arg = addrExpr;
	531	castExpr->result = new PointerType( Type::Qualifiers(), castExpr->result );
	532	return castExpr;
	533	}
[cb43451]	534	}
[8499c707]	535	return addrExpr;
[cb43451]	536	}
	537
	538	Expression * CollapseAddrDeref::postmutate( ApplicationExpr * appExpr ) {
	539	if ( isIntrinsicReference( appExpr ) ) {
	540	std::string fname = InitTweak::getFunctionName( appExpr );
	541	if ( fname == "*?" ) {
	542	Expression * arg = InitTweak::getCallArg( appExpr, 0 );
	543	// xxx - this isn't right, because it can remove casts that should be there...
	544	// while ( CastExpr * castExpr = dynamic_cast< CastExpr * >( arg ) ) {
	545	// arg = castExpr->get_arg();
	546	// }
	547	if ( AddressExpr * addrExpr = dynamic_cast< AddressExpr * >( arg ) ) {
[b1ccdfd]	548	Expression * ret = addrExpr->arg;
	549	ret->env = appExpr->env;
	550	addrExpr->arg = nullptr;
	551	appExpr->env = nullptr;
[cb43451]	552	delete appExpr;
	553	return ret;
	554	}
	555	}
	556	}
	557	return appExpr;
	558	}
[01aeade]	559	} // namespace
[51b7345]	560	} // namespace GenPoly
[01aeade]	561
[51587aa]	562	// Local Variables: //
	563	// tab-width: 4 //
	564	// mode: c++ //
	565	// compile-command: "make install" //
	566	// End: //

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