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source: src/GenPoly/Lvalue.cc @ 9939dc3

ADTast-experimentalpthread-emulationqualifiedEnum

Last change on this file since 9939dc3 was 9939dc3, checked in by Andrew Beach <ajbeach@…>, 2 years ago
Reduced the number of object files linked into the demangler. Some of the divisions are rather odd, Lvalue2 and FixMain2, but they should be a better base to work from. Also improved the calling of the impurity detector visitors slightly.
Property mode set to `100644`
File size: 23.4 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
[9939dc3]	11	// Last Modified By : Andrew Beach
	12	// Last Modified On : Mon May 16 14:09:00 2022
	13	// Update Count : 8
[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
[9939dc3]	127	// Stored elsewhere (Lvalue2, initially false).
	128	extern bool referencesEliminated;
[b0440b7]	129
[b1ccdfd]	130	void convertLvalue( std::list< Declaration* > & translationUnit ) {
[1d776fd]	131	PassVisitor<ReferenceConversions> refCvt;
	132	PassVisitor<ReferenceTypeElimination> elim;
	133	PassVisitor<GeneralizedLvalue> genLval;
	134	PassVisitor<FixIntrinsicArgs> fixer;
[cb43451]	135	PassVisitor<CollapseAddrDeref> collapser;
[8499c707]	136	PassVisitor<AddrRef> addrRef;
	137	PassVisitor<FixIntrinsicResult> intrinsicResults;
	138	mutateAll( translationUnit, intrinsicResults );
	139	mutateAll( translationUnit, addrRef );
[1d776fd]	140	mutateAll( translationUnit, refCvt );
	141	mutateAll( translationUnit, fixer );
[cb43451]	142	mutateAll( translationUnit, collapser );
[8499c707]	143	mutateAll( translationUnit, genLval );
[8a6cf7e]	144	mutateAll( translationUnit, elim ); // last because other passes need reference types to work
[b0440b7]	145
	146	// from this point forward, no other pass should create reference types.
	147	referencesEliminated = true;
[01aeade]	148	}
	149
[acd7c5dd]	150	Expression * generalizedLvalue( Expression * expr ) {
[9236060]	151	PassVisitor<GeneralizedLvalue> genLval;
[acd7c5dd]	152	return expr->acceptMutator( genLval );
	153	}
	154
[01aeade]	155	namespace {
[85b2300]	156	// true for intrinsic function calls that return an lvalue in C
[1d776fd]	157	bool isIntrinsicReference( Expression * expr ) {
[85b2300]	158	// known intrinsic-reference prelude functions
	159	static std::set<std::string> lvalueFunctions = { "*?", "?[?]" };
[8a6cf7e]	160	if ( UntypedExpr * untyped = dynamic_cast< UntypedExpr * >( expr ) ) {
	161	std::string fname = InitTweak::getFunctionName( untyped );
[85b2300]	162	return lvalueFunctions.count(fname);
[1d776fd]	163	} else if ( ApplicationExpr * appExpr = dynamic_cast< ApplicationExpr * > ( expr ) ) {
	164	if ( DeclarationWithType * func = InitTweak::getFunction( appExpr ) ) {
[85b2300]	165	return func->linkage == LinkageSpec::Intrinsic && lvalueFunctions.count(func->name);
[1d776fd]	166	}
[ce8c12f]	167	}
[1d776fd]	168	return false;
[ce8c12f]	169	}
	170
[8499c707]	171	Expression * FixIntrinsicResult::postmutate( ApplicationExpr * appExpr ) {
[78cdb06]	172	if ( skip != SkipInProgress && isIntrinsicReference( appExpr ) ) {
[8499c707]	173	// eliminate reference types from intrinsic applications - now they return lvalues
[c1ec14f]	174	ReferenceType * result = strict_dynamic_cast< ReferenceType * >( appExpr->result );
	175	appExpr->result = result->base->clone();
[9aaac6e9]	176	if ( ! inIntrinsic ) {
	177	// when not in an intrinsic function, add a cast to
	178	// don't add cast when in an intrinsic function, since they already have the cast
	179	Expression * ret = new CastExpr( appExpr, result );
[b1ccdfd]	180	std::swap( ret->env, appExpr->env );
[9aaac6e9]	181	return ret;
	182	}
	183	delete result;
[8499c707]	184	}
	185	return appExpr;
	186	}
	187
[9aaac6e9]	188	void FixIntrinsicResult::premutate( FunctionDecl * funcDecl ) {
	189	GuardValue( inIntrinsic );
[c1ec14f]	190	inIntrinsic = funcDecl->linkage == LinkageSpec::Intrinsic;
[9aaac6e9]	191	}
	192
[1d776fd]	193	Expression * FixIntrinsicArgs::postmutate( ApplicationExpr * appExpr ) {
[9a34b5a]	194	// intrinsic functions don't really take reference-typed parameters, so they require an implicit dereference on their arguments.
[1d776fd]	195	if ( DeclarationWithType * function = InitTweak::getFunction( appExpr ) ) {
[d335627]	196	FunctionType * ftype = GenPoly::getFunctionType( function->get_type() );
	197	assertf( ftype, "Function declaration does not have function type." );
	198	// can be of differing lengths only when function is variadic
[b1ccdfd]	199	assertf( ftype->parameters.size() == appExpr->args.size() \|\| ftype->isVarArgs, "ApplicationExpr args do not match formal parameter type." );
[b0440b7]	200
	201
[d335627]	202	unsigned int i = 0;
[b1ccdfd]	203	const unsigned int end = ftype->parameters.size();
[0b73f0c]	204
	205	/// The for loop may eagerly dereference the iterators and fail on empty lists
	206	if(i == end) { return appExpr; }
[b1ccdfd]	207	for ( auto p : unsafe_group_iterate( appExpr->args, ftype->parameters ) ) {
[d335627]	208	Expression *& arg = std::get<0>( p );
	209	Type * formal = std::get<1>( p )->get_type();
	210	PRINT(
	211	std::cerr << "pair<0>: " << arg << std::endl;
[a9b1b0c]	212	std::cerr << " -- " << arg->result << std::endl;
[d335627]	213	std::cerr << "pair<1>: " << formal << std::endl;
	214	)
	215	if ( dynamic_cast<ReferenceType*>( formal ) ) {
[a9b1b0c]	216	PRINT(
	217	std::cerr << "===formal is reference" << std::endl;
	218	)
	219	// TODO: it's likely that the second condition should be ... && ! isIntrinsicReference( arg ), but this requires investigation.
[207b496]	220
[85b2300]	221	if ( function->linkage != LinkageSpec::Intrinsic && isIntrinsicReference( arg ) ) {
[207b496]	222	// needed for definition of prelude functions, etc.
[a9b1b0c]	223	// if argument is dereference or array subscript, the result isn't REALLY a reference, but non-intrinsic functions expect a reference: take address
[a3323db1]	224
	225	// NOTE: previously, this condition fixed
	226	// void f(int *&);
	227	// int & x = ...;
	228	// f(&x);
	229	// But now this is taken care of by a reference cast added by AddrRef. Need to find a new
	230	// example or remove this branch.
[207b496]	231
[a9b1b0c]	232	PRINT(
	233	std::cerr << "===is intrinsic arg in non-intrinsic call - adding address" << std::endl;
	234	)
	235	arg = new AddressExpr( arg );
[da7fe39]	236	// } else if ( function->get_linkage() == LinkageSpec::Intrinsic && InitTweak::getPointerBase( arg->result ) ) {
[85b2300]	237	} else if ( function->linkage == LinkageSpec::Intrinsic && arg->result->referenceDepth() != 0 ) {
[a9b1b0c]	238	// argument is a 'real' reference, but function expects a C lvalue: add a dereference to the reference-typed argument
	239	PRINT(
	240	std::cerr << "===is non-intrinsic arg in intrinsic call - adding deref to arg" << std::endl;
	241	)
[b1ccdfd]	242	Type * baseType = InitTweak::getPointerBase( arg->result );
	243	assertf( baseType, "parameter is reference, arg must be pointer or reference: %s", toString( arg->result ).c_str() );
[d335627]	244	PointerType * ptrType = new PointerType( Type::Qualifiers(), baseType->clone() );
[b1ccdfd]	245	delete arg->result;
[207b496]	246	arg->result = ptrType;
[d335627]	247	arg = mkDeref( arg );
[207b496]	248	// assertf( arg->result->referenceDepth() == 0, "Reference types should have been eliminated from intrinsic function calls, but weren't: %s", toCString( arg->result ) );
[1d776fd]	249	}
	250	}
[d335627]	251	++i;
[aaeacf4]	252	if (i == end) break;
[baba5d8]	253	}
[1d776fd]	254	}
	255	return appExpr;
[01aeade]	256	}
	257
[8499c707]	258	// idea: &&&E: get outer &, inner &
[a3323db1]	259	// at inner &, record depth D of reference type of argument of &
[8499c707]	260	// at outer &, add D derefs.
[a3323db1]	261	void AddrRef::handleNonAddr( Expression * ) {
	262	// non-address-of: reset status variables:
	263	// * current expr is NOT the first address-of expr in an address-of chain
	264	// * next seen address-of expr IS the first in the chain.
[8499c707]	265	GuardValue( current );
	266	GuardValue( first );
	267	current = false;
	268	first = true;
	269	}
	270
[a3323db1]	271	void AddrRef::premutate( Expression * expr ) {
	272	handleNonAddr( expr );
	273	GuardValue( addCast );
	274	addCast = false;
	275	}
	276
[8135d4c]	277	void AddrRef::premutate( AddressExpr * ) {
[8499c707]	278	GuardValue( current );
	279	GuardValue( first );
[a3323db1]	280	current = first; // is this the first address-of in the chain?
	281	first = false; // from here out, no longer possible for next address-of to be first in chain
	282	if ( current ) { // this is the outermost address-of in a chain
[8499c707]	283	GuardValue( refDepth );
[a3323db1]	284	refDepth = 0; // set depth to 0 so that postmutate can find the innermost address-of easily
[8499c707]	285	}
	286	}
	287
	288	Expression * AddrRef::postmutate( AddressExpr * addrExpr ) {
[f74eb47]	289	PRINT( std::cerr << "addr ref at " << addrExpr << std::endl; )
[8499c707]	290	if ( refDepth == 0 ) {
[f74eb47]	291	PRINT( std::cerr << "depth 0, get new depth..." << std::endl; )
[a3323db1]	292	// this is the innermost address-of in a chain, record depth D
[b1ccdfd]	293	if ( ! isIntrinsicReference( addrExpr->arg ) ) {
[8499c707]	294	// try to avoid ?[?]
[a3323db1]	295	// 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]	296	refDepth = addrExpr->arg->result->referenceDepth();
[f74eb47]	297	PRINT( std::cerr << "arg not intrinsic reference, new depth is: " << refDepth << std::endl; )
[a3323db1]	298	} else {
	299	assertf( false, "AddrRef : address-of should not have intrinsic reference argument: %s", toCString( addrExpr->arg ) );
[8499c707]	300	}
	301	}
[a3323db1]	302	if ( current ) { // this is the outermost address-of in a chain
[f74eb47]	303	PRINT( std::cerr << "current, depth is: " << refDepth << std::endl; )
[8499c707]	304	Expression * ret = addrExpr;
	305	while ( refDepth ) {
[a3323db1]	306	// add one dereference for each
[8499c707]	307	ret = mkDeref( ret );
	308	refDepth--;
	309	}
[a3323db1]	310
[57acae0]	311	// if addrExpr depth is 0, then the result is a pointer because the arg was depth 1 and not lvalue.
	312	// This means the dereference result is not a reference, is lvalue, and one less pointer depth than
	313	// the addrExpr. Thus the cast is meaningless.
	314	// TODO: One thing to double check is whether it is possible for the types to differ outside of the single
	315	// pointer level (i.e. can the base type of addrExpr differ from the type of addrExpr-arg?).
	316	// If so then the cast might need to be added, conditional on a more sophisticated check.
	317	if ( addCast && addrExpr->result->referenceDepth() != 0 ) {
	318	PRINT( std::cerr << "adding cast to " << addrExpr->result << std::endl; )
[a3323db1]	319	return new CastExpr( ret, addrExpr->result->clone() );
	320	}
[8499c707]	321	return ret;
	322	}
[f74eb47]	323	PRINT( std::cerr << "not current..." << std::endl; )
[8499c707]	324	return addrExpr;
	325	}
	326
[a3323db1]	327	void AddrRef::premutate( ApplicationExpr * appExpr ) {
	328	visit_children = false;
	329	GuardValue( addCast );
	330	handleNonAddr( appExpr );
	331	for ( Expression *& arg : appExpr->args ) {
	332	// each argument with address-of requires a cast
	333	addCast = true;
	334	arg = arg->acceptMutator( *visitor );
	335	}
	336	}
	337
	338	void AddrRef::premutate( SingleInit * ) {
	339	GuardValue( addCast );
	340	// each initialization context with address-of requires a cast
	341	addCast = true;
	342	}
	343
	344
[8a6cf7e]	345	Expression * ReferenceConversions::postmutate( AddressExpr * addrExpr ) {
	346	// Inner expression may have been lvalue to reference conversion, which becomes an address expression.
	347	// In this case, remove the outer address expression and return the argument.
	348	// TODO: It's possible that this might catch too much and require a more sophisticated check.
	349	return addrExpr;
	350	}
	351
[1d776fd]	352	Expression * ReferenceConversions::postmutate( CastExpr * castExpr ) {
[9a34b5a]	353	// xxx - is it possible to convert directly between reference types with a different base? E.g.,
	354	// int x;
	355	// (double&)x;
	356	// At the moment, I am working off of the assumption that this is illegal, thus the cast becomes redundant
	357	// after this pass, so trash the cast altogether. If that changes, care must be taken to insert the correct
	358	// pointer casts in the right places.
	359
[a4d188f]	360	// Note: reference depth difference is the determining factor in what code is run, rather than whether something is
	361	// reference type or not, since conversion still needs to occur when both types are references that differ in depth.
[31cb252]	362
	363	Type * destType = castExpr->result;
	364	Type * srcType = castExpr->arg->result;
[c9c9ac4f]	365	assertf( destType, "Cast to no type in: %s", toCString( castExpr ) );
	366	assertf( srcType, "Cast from no type in: %s", toCString( castExpr ) );
[31cb252]	367	int depth1 = destType->referenceDepth();
	368	int depth2 = srcType->referenceDepth();
	369	int diff = depth1 - depth2;
	370
[2d80111]	371	if ( diff > 0 && ! castExpr->arg->get_lvalue() ) {
[31cb252]	372	// rvalue to reference conversion -- introduce temporary
	373	// know that reference depth of cast argument is 0, need to introduce n temporaries for reference depth of n, e.g.
	374	// (int &&&)3;
	375	// becomes
	376	// int __ref_tmp_0 = 3;
	377	// int & __ref_tmp_1 = _&_ref_tmp_0;
	378	// int && __ref_tmp_2 = &__ref_tmp_1;
	379	// &__ref_tmp_2;
[453b586]	380	// the last & comes from the remaining reference conversion code
[2348881]	381	SemanticWarning( castExpr->arg->location, Warning::RvalueToReferenceConversion, toCString( castExpr->arg ) );
[31cb252]	382
	383	static UniqueName tempNamer( "__ref_tmp_" );
	384	ObjectDecl * temp = ObjectDecl::newObject( tempNamer.newName(), castExpr->arg->result->clone(), new SingleInit( castExpr->arg ) );
	385	PRINT( std::cerr << "made temp: " << temp << std::endl; )
	386	stmtsToAddBefore.push_back( new DeclStmt( temp ) );
[a4d188f]	387	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]	388	ObjectDecl * newTemp = ObjectDecl::newObject( tempNamer.newName(), new ReferenceType( Type::Qualifiers(), temp->type->clone() ), new SingleInit( new AddressExpr( new VariableExpr( temp ) ) ) );
	389	PRINT( std::cerr << "made temp" << i << ": " << newTemp << std::endl; )
	390	stmtsToAddBefore.push_back( new DeclStmt( newTemp ) );
	391	temp = newTemp;
	392	}
	393	// update diff so that remaining code works out correctly
	394	castExpr->arg = new VariableExpr( temp );
	395	PRINT( std::cerr << "update cast to: " << castExpr << std::endl; )
	396	srcType = castExpr->arg->result;
	397	depth2 = srcType->referenceDepth();
	398	diff = depth1 - depth2;
	399	assert( diff == 1 );
	400	}
[fc56cdbf]	401
[a4d188f]	402	// handle conversion between different depths
[31cb252]	403	PRINT (
	404	if ( depth1 \|\| depth2 ) {
	405	std::cerr << "destType: " << destType << " / srcType: " << srcType << std::endl;
	406	std::cerr << "depth: " << depth1 << " / " << depth2 << std::endl;
	407	}
	408	)
	409	if ( diff > 0 ) {
	410	// conversion to type with more depth (e.g. int & -> int &&): add address-of for each level of difference
	411	Expression * ret = castExpr->arg;
	412	for ( int i = 0; i < diff; ++i ) {
	413	ret = new AddressExpr( ret );
	414	}
[2d80111]	415	if ( castExpr->arg->get_lvalue() && ! ResolvExpr::typesCompatible( srcType, strict_dynamic_cast<ReferenceType *>( destType )->base, SymTab::Indexer() ) ) {
[31cb252]	416	// must keep cast if cast-to type is different from the actual type
	417	castExpr->arg = ret;
[1d776fd]	418	return castExpr;
	419	}
[31cb252]	420	ret->env = castExpr->env;
	421	delete ret->result;
	422	ret->result = castExpr->result;
	423	castExpr->env = nullptr;
	424	castExpr->arg = nullptr;
	425	castExpr->result = nullptr;
	426	delete castExpr;
	427	return ret;
	428	} else if ( diff < 0 ) {
	429	// conversion to type with less depth (e.g. int && -> int &): add dereferences for each level of difference
	430	diff = -diff; // care only about magnitude now
[0690350]	431	Expression * ret = castExpr->arg;
[31cb252]	432	for ( int i = 0; i < diff; ++i ) {
[9191a8e]	433	ret = mkDeref( ret );
[ba89e9b7]	434	// xxx - try removing one reference here? actually, looks like mkDeref already does this, so more closely look at the types generated.
[9191a8e]	435	}
[31cb252]	436	if ( ! ResolvExpr::typesCompatibleIgnoreQualifiers( destType->stripReferences(), srcType->stripReferences(), SymTab::Indexer() ) ) {
[8a6cf7e]	437	// must keep cast if types are different
[0690350]	438	castExpr->arg = ret;
[31cb252]	439	return castExpr;
[8a6cf7e]	440	}
[31cb252]	441	ret->env = castExpr->env;
	442	delete ret->result;
	443	ret->result = castExpr->result;
[b4f8808]	444	assert( ret->get_lvalue() ); // ensure result is lvalue
[31cb252]	445	castExpr->env = nullptr;
	446	castExpr->arg = nullptr;
	447	castExpr->result = nullptr;
	448	delete castExpr;
[9191a8e]	449	return ret;
[31cb252]	450	} else {
	451	assert( diff == 0 );
	452	// conversion between references of the same depth
[70a5acf]	453	if ( ResolvExpr::typesCompatible( castExpr->result, castExpr->arg->result, SymTab::Indexer() ) && castExpr->isGenerated ) {
	454	// Remove useless generated casts
	455	PRINT(
	456	std::cerr << "types are compatible, removing cast: " << castExpr << std::endl;
	457	std::cerr << "-- " << castExpr->result << std::endl;
	458	std::cerr << "-- " << castExpr->arg->result << std::endl;
	459	)
	460	Expression * ret = castExpr->arg;
	461	castExpr->arg = nullptr;
	462	std::swap( castExpr->env, ret->env );
	463	delete castExpr;
	464	return ret;
	465	}
[31cb252]	466	return castExpr;
[1d776fd]	467	}
[01aeade]	468	}
[b6fd751]	469
[1d776fd]	470	Type * ReferenceTypeElimination::postmutate( ReferenceType * refType ) {
[b1ccdfd]	471	Type * base = refType->base;
[8a6cf7e]	472	Type::Qualifiers qualifiers = refType->get_qualifiers();
[b1ccdfd]	473	refType->base = nullptr;
[1d776fd]	474	delete refType;
[8a6cf7e]	475	return new PointerType( qualifiers, base );
[ce8c12f]	476	}
	477
[acd7c5dd]	478	template<typename Func>
	479	Expression * GeneralizedLvalue::applyTransformation( Expression * expr, Expression * arg, Func mkExpr ) {
	480	if ( CommaExpr * commaExpr = dynamic_cast< CommaExpr * >( arg ) ) {
[b1ccdfd]	481	Expression * arg1 = commaExpr->arg1->clone();
	482	Expression * arg2 = commaExpr->arg2->clone();
[9236060]	483	Expression * ret = new CommaExpr( arg1, mkExpr( arg2 )->acceptMutator( *visitor ) );
[b1ccdfd]	484	ret->env = expr->env;
	485	expr->env = nullptr;
[acd7c5dd]	486	delete expr;
[8499c707]	487	return ret;
[acd7c5dd]	488	} else if ( ConditionalExpr * condExpr = dynamic_cast< ConditionalExpr * >( arg ) ) {
[b1ccdfd]	489	Expression * arg1 = condExpr->arg1->clone();
	490	Expression * arg2 = condExpr->arg2->clone();
	491	Expression * arg3 = condExpr->arg3->clone();
[9236060]	492	ConditionalExpr * ret = new ConditionalExpr( arg1, mkExpr( arg2 )->acceptMutator( visitor ), mkExpr( arg3 )->acceptMutator( visitor ) );
[b1ccdfd]	493	ret->env = expr->env;
	494	expr->env = nullptr;
[acd7c5dd]	495	delete expr;
	496
	497	// conditional expr type may not be either of the argument types, need to unify
	498	using namespace ResolvExpr;
	499	Type* commonType = nullptr;
	500	TypeEnvironment newEnv;
	501	AssertionSet needAssertions, haveAssertions;
	502	OpenVarSet openVars;
[b1ccdfd]	503	unify( ret->arg2->result, ret->arg3->result, newEnv, needAssertions, haveAssertions, openVars, SymTab::Indexer(), commonType );
	504	ret->result = commonType ? commonType : ret->arg2->result->clone();
[8499c707]	505	return ret;
[b6fd751]	506	}
[acd7c5dd]	507	return expr;
	508	}
	509
[9236060]	510	Expression * GeneralizedLvalue::postmutate( MemberExpr * memExpr ) {
[b1ccdfd]	511	return applyTransformation( memExpr, memExpr->aggregate, [=]( Expression * aggr ) { return new MemberExpr( memExpr->member, aggr ); } );
[acd7c5dd]	512	}
	513
[9236060]	514	Expression * GeneralizedLvalue::postmutate( AddressExpr * addrExpr ) {
[b1ccdfd]	515	return applyTransformation( addrExpr, addrExpr->arg, []( Expression * arg ) { return new AddressExpr( arg ); } );
[b6fd751]	516	}
[cb43451]	517
[8499c707]	518	Expression * CollapseAddrDeref::postmutate( AddressExpr * addrExpr ) {
[b1ccdfd]	519	Expression * arg = addrExpr->arg;
[cb43451]	520	if ( isIntrinsicReference( arg ) ) {
	521	std::string fname = InitTweak::getFunctionName( arg );
	522	if ( fname == "*?" ) {
	523	Expression *& arg0 = InitTweak::getCallArg( arg, 0 );
	524	Expression * ret = arg0;
[b1ccdfd]	525	ret->set_env( addrExpr->env );
[cb43451]	526	arg0 = nullptr;
[b1ccdfd]	527	addrExpr->env = nullptr;
[8499c707]	528	delete addrExpr;
[cb43451]	529	return ret;
	530	}
[bf7b6015]	531	} else if ( CastExpr * castExpr = dynamic_cast< CastExpr * > ( arg ) ) {
	532	// need to move cast to pointer type out a level since address of pointer
	533	// is not valid C code (can be introduced in prior passes, e.g., InstantiateGeneric)
	534	if ( InitTweak::getPointerBase( castExpr->result ) ) {
	535	addrExpr->arg = castExpr->arg;
	536	castExpr->arg = addrExpr;
	537	castExpr->result = new PointerType( Type::Qualifiers(), castExpr->result );
	538	return castExpr;
	539	}
[cb43451]	540	}
[8499c707]	541	return addrExpr;
[cb43451]	542	}
	543
	544	Expression * CollapseAddrDeref::postmutate( ApplicationExpr * appExpr ) {
	545	if ( isIntrinsicReference( appExpr ) ) {
	546	std::string fname = InitTweak::getFunctionName( appExpr );
	547	if ( fname == "*?" ) {
	548	Expression * arg = InitTweak::getCallArg( appExpr, 0 );
	549	// xxx - this isn't right, because it can remove casts that should be there...
	550	// while ( CastExpr * castExpr = dynamic_cast< CastExpr * >( arg ) ) {
	551	// arg = castExpr->get_arg();
	552	// }
	553	if ( AddressExpr * addrExpr = dynamic_cast< AddressExpr * >( arg ) ) {
[b1ccdfd]	554	Expression * ret = addrExpr->arg;
	555	ret->env = appExpr->env;
	556	addrExpr->arg = nullptr;
	557	appExpr->env = nullptr;
[cb43451]	558	delete appExpr;
	559	return ret;
	560	}
	561	}
	562	}
	563	return appExpr;
	564	}
[01aeade]	565	} // namespace
[51b7345]	566	} // namespace GenPoly
[01aeade]	567
[51587aa]	568	// Local Variables: //
	569	// tab-width: 4 //
	570	// mode: c++ //
	571	// compile-command: "make install" //
	572	// End: //

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