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source: src/ResolvExpr/Resolver.cc @ 496ffc17

Last change on this file since 496ffc17 was 7329b0a, checked in by Andrew Beach <ajbeach@…>, 5 months ago
advance_to_mutex has been replaced nextMutex.
Property mode set to `100644`
File size: 44.8 KB

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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	//
7	// Resolver.cc --
8	//
9	// Author : Aaron B. Moss
10	// Created On : Sun May 17 12:17:01 2015
11	// Last Modified By : Peter A. Buhr
12	// Last Modified On : Thu Dec 14 18:44:43 2023
13	// Update Count : 251
14	//
15
16	#include <cassert> // for strict_dynamic_cast, assert
17	#include <memory> // for allocator, allocator_traits<...
18	#include <tuple> // for get
19	#include <vector> // for vector
20
21	#include "Candidate.hpp"
22	#include "CandidateFinder.hpp"
23	#include "CurrentObject.h" // for CurrentObject
24	#include "RenameVars.h" // for RenameVars, global_renamer
25	#include "Resolver.h"
26	#include "ResolveTypeof.h"
27	#include "ResolveMode.hpp" // for ResolveMode
28	#include "typeops.h" // for extractResultType
29	#include "Unify.h" // for unify
30	#include "CompilationState.h"
31	#include "AST/Decl.hpp"
32	#include "AST/Init.hpp"
33	#include "AST/Pass.hpp"
34	#include "AST/Print.hpp"
35	#include "AST/SymbolTable.hpp"
36	#include "AST/Type.hpp"
37	#include "Common/Eval.h" // for eval
38	#include "Common/Iterate.hpp" // for group_iterate
39	#include "Common/SemanticError.h" // for SemanticError
40	#include "Common/Stats/ResolveTime.h" // for ResolveTime::start(), ResolveTime::stop()
41	#include "Common/ToString.hpp" // for toCString
42	#include "Common/UniqueName.h" // for UniqueName
43	#include "InitTweak/GenInit.h"
44	#include "InitTweak/InitTweak.h" // for isIntrinsicSingleArgCallStmt
45	#include "SymTab/Mangler.h" // for Mangler
46	#include "Tuples/Tuples.h"
47	#include "Validate/FindSpecialDecls.h" // for SizeType
48
49	using namespace std;
50
51	namespace ResolvExpr {
52	namespace {
53	/// Finds deleted expressions in an expression tree
54	struct DeleteFinder final : public ast::WithShortCircuiting, public ast::WithVisitorRef<DeleteFinder> {
55	const ast::DeletedExpr * result = nullptr;
56
57	void previsit( const ast::DeletedExpr * expr ) {
58	if ( result ) { visit_children = false; }
59	else { result = expr; }
60	}
61
62	void previsit( const ast::Expr * expr ) {
63	if ( result ) { visit_children = false; }
64	if (expr->inferred.hasParams()) {
65	for (auto & imp : expr->inferred.inferParams() ) {
66	imp.second.expr->accept(*visitor);
67	}
68	}
69	}
70	};
71
72	struct ResolveDesignators final : public ast::WithShortCircuiting {
73	ResolveContext& context;
74	bool result = false;
75
76	ResolveDesignators( ResolveContext& _context ): context{_context} {};
77
78	void previsit( const ast::Node * ) {
79	// short circuit if we already know there are designations
80	if ( result ) visit_children = false;
81	}
82
83	void previsit( const ast::Designation * des ) {
84	if ( result ) visit_children = false;
85	else if ( ! des->designators.empty() ) {
86	if ( (des->designators.size() == 1) ) {
87	const ast::Expr * designator = des->designators.at(0);
88	if ( const ast::NameExpr * designatorName = dynamic_cast<const ast::NameExpr *>(designator) ) {
89	auto candidates = context.symtab.lookupId(designatorName->name);
90	for ( auto candidate : candidates ) {
91	if ( dynamic_cast<const ast::EnumInstType *>(candidate.id->get_type()) ) {
92	result = true;
93	break;
94	}
95	}
96	}
97	}
98	visit_children = false;
99	}
100	}
101	};
102	} // anonymous namespace
103	/// Check if this expression is or includes a deleted expression
104	const ast::DeletedExpr * findDeletedExpr( const ast::Expr * expr ) {
105	return ast::Pass<DeleteFinder>::read( expr );
106	}
107
108	namespace {
109	/// always-accept candidate filter
110	bool anyCandidate( const Candidate & ) { return true; }
111
112	/// Calls the CandidateFinder and finds the single best candidate
113	CandidateRef findUnfinishedKindExpression(
114	const ast::Expr * untyped, const ResolveContext & context, const std::string & kind,
115	std::function<bool(const Candidate &)> pred = anyCandidate, ResolveMode mode = {}
116	) {
117	if ( ! untyped ) return nullptr;
118
119	// xxx - this isn't thread-safe, but should work until we parallelize the resolver
120	static unsigned recursion_level = 0;
121
122	++recursion_level;
123	ast::TypeEnvironment env;
124	CandidateFinder finder( context, env );
125	finder.allowVoid = true;
126	finder.find( untyped, recursion_level == 1 ? mode.atTopLevel() : mode );
127	--recursion_level;
128
129	// produce a filtered list of candidates
130	CandidateList candidates;
131	for ( auto & cand : finder.candidates ) {
132	if ( pred( *cand ) ) { candidates.emplace_back( cand ); }
133	}
134
135	// produce invalid error if no candidates
136	if ( candidates.empty() ) {
137	SemanticError( untyped,
138	toString( "No reasonable alternatives for ", kind, (kind != "" ? " " : ""),
139	"expression: ") );
140	}
141
142	// search for cheapest candidate
143	CandidateList winners;
144	bool seen_undeleted = false;
145	for ( CandidateRef & cand : candidates ) {
146	int c = winners.empty() ? -1 : cand->cost.compare( winners.front()->cost );
147
148	if ( c > 0 ) continue; // skip more expensive than winner
149
150	if ( c < 0 ) {
151	// reset on new cheapest
152	seen_undeleted = ! findDeletedExpr( cand->expr );
153	winners.clear();
154	} else /* if ( c == 0 ) */ {
155	if ( findDeletedExpr( cand->expr ) ) {
156	// skip deleted expression if already seen one equivalent-cost not
157	if ( seen_undeleted ) continue;
158	} else if ( ! seen_undeleted ) {
159	// replace list of equivalent-cost deleted expressions with one non-deleted
160	winners.clear();
161	seen_undeleted = true;
162	}
163	}
164
165	winners.emplace_back( std::move( cand ) );
166	}
167
168	// promote candidate.cvtCost to .cost
169	// promoteCvtCost( winners );
170
171	// produce ambiguous errors, if applicable
172	if ( winners.size() != 1 ) {
173	std::ostringstream stream;
174	stream << "Cannot choose between " << winners.size() << " alternatives for "
175	<< kind << (kind != "" ? " " : "") << "expression\n";
176	ast::print( stream, untyped );
177	stream << " Alternatives are:\n";
178	print( stream, winners, 1 );
179	SemanticError( untyped->location, stream.str() );
180	}
181
182	// single selected choice
183	CandidateRef & choice = winners.front();
184
185	// fail on only expression deleted
186	if ( ! seen_undeleted ) {
187	SemanticError( untyped->location, choice->expr.get(), "Unique best alternative "
188	"includes deleted identifier in " );
189	}
190
191	return std::move( choice );
192	}
193
194	/// Strips extraneous casts out of an expression
195	struct StripCasts final {
196	const ast::Expr * postvisit( const ast::CastExpr * castExpr ) {
197	if (
198	castExpr->isGenerated == ast::GeneratedCast
199	&& typesCompatible( castExpr->arg->result, castExpr->result )
200	) {
201	// generated cast is the same type as its argument, remove it after keeping env
202	return ast::mutate_field(
203	castExpr->arg.get(), &ast::Expr::env, castExpr->env );
204	}
205	return castExpr;
206	}
207
208	static void strip( ast::ptr< ast::Expr > & expr ) {
209	ast::Pass< StripCasts > stripper;
210	expr = expr->accept( stripper );
211	}
212	};
213
214	/// Swaps argument into expression pointer, saving original environment
215	void swap_and_save_env( ast::ptr< ast::Expr > & expr, const ast::Expr * newExpr ) {
216	ast::ptr< ast::TypeSubstitution > env = expr->env;
217	expr.set_and_mutate( newExpr )->env = env;
218	}
219
220	/// Removes cast to type of argument (unlike StripCasts, also handles non-generated casts)
221	void removeExtraneousCast( ast::ptr<ast::Expr> & expr ) {
222	if ( const ast::CastExpr * castExpr = expr.as< ast::CastExpr >() ) {
223	if ( typesCompatible( castExpr->arg->result, castExpr->result ) ) {
224	// cast is to the same type as its argument, remove it
225	swap_and_save_env( expr, castExpr->arg );
226	}
227	}
228	}
229
230
231	} // anonymous namespace
232	/// Establish post-resolver invariants for expressions
233	void finishExpr(
234	ast::ptr< ast::Expr > & expr, const ast::TypeEnvironment & env,
235	const ast::TypeSubstitution * oldenv = nullptr
236	) {
237	// set up new type substitution for expression
238	ast::ptr< ast::TypeSubstitution > newenv =
239	oldenv ? oldenv : new ast::TypeSubstitution{};
240	env.writeToSubstitution( *newenv.get_and_mutate() );
241	expr.get_and_mutate()->env = std::move( newenv );
242	// remove unncecessary casts
243	StripCasts::strip( expr );
244	}
245
246	ast::ptr< ast::Expr > resolveInVoidContext(
247	const ast::Expr * expr, const ResolveContext & context,
248	ast::TypeEnvironment & env
249	) {
250	assertf( expr, "expected a non-null expression" );
251
252	// set up and resolve expression cast to void
253	ast::ptr< ast::CastExpr > untyped = new ast::CastExpr{ expr };
254	CandidateRef choice = findUnfinishedKindExpression(
255	untyped, context, "", anyCandidate, ResolveMode::withAdjustment() );
256
257	// a cast expression has either 0 or 1 interpretations (by language rules);
258	// if 0, an exception has already been thrown, and this code will not run
259	const ast::CastExpr * castExpr = choice->expr.strict_as< ast::CastExpr >();
260	env = std::move( choice->env );
261
262	return castExpr->arg;
263	}
264
265	/// Resolve `untyped` to the expression whose candidate is the best match for a `void`
266	/// context.
267	ast::ptr< ast::Expr > findVoidExpression(
268	const ast::Expr * untyped, const ResolveContext & context
269	) {
270	ast::TypeEnvironment env;
271	ast::ptr< ast::Expr > newExpr = resolveInVoidContext( untyped, context, env );
272	finishExpr( newExpr, env, untyped->env );
273	return newExpr;
274	}
275
276	namespace {
277
278
279	/// resolve `untyped` to the expression whose candidate satisfies `pred` with the
280	/// lowest cost, returning the resolved version
281	ast::ptr< ast::Expr > findKindExpression(
282	const ast::Expr * untyped, const ResolveContext & context,
283	std::function<bool(const Candidate &)> pred = anyCandidate,
284	const std::string & kind = "", ResolveMode mode = {}
285	) {
286	if ( ! untyped ) return {};
287	CandidateRef choice =
288	findUnfinishedKindExpression( untyped, context, kind, pred, mode );
289	ResolvExpr::finishExpr( choice->expr, choice->env, untyped->env );
290	return std::move( choice->expr );
291	}
292
293	/// Resolve `untyped` to the single expression whose candidate is the best match
294	ast::ptr< ast::Expr > findSingleExpression(
295	const ast::Expr * untyped, const ResolveContext & context
296	) {
297	Stats::ResolveTime::start( untyped );
298	auto res = findKindExpression( untyped, context );
299	Stats::ResolveTime::stop();
300	return res;
301	}
302	} // anonymous namespace
303
304	ast::ptr< ast::Expr > findSingleExpression(
305	const ast::Expr * untyped, const ast::Type * type,
306	const ResolveContext & context
307	) {
308	assert( untyped && type );
309	ast::ptr< ast::Expr > castExpr = new ast::CastExpr{ untyped, type };
310	ast::ptr< ast::Expr > newExpr = findSingleExpression( castExpr, context );
311	removeExtraneousCast( newExpr );
312	return newExpr;
313	}
314
315	namespace {
316	bool structOrUnion( const Candidate & i ) {
317	const ast::Type * t = i.expr->result->stripReferences();
318	return dynamic_cast< const ast::StructInstType * >( t ) \|\| dynamic_cast< const ast::UnionInstType * >( t );
319	}
320	/// Predicate for "Candidate has integral type"
321	bool hasIntegralType( const Candidate & i ) {
322	const ast::Type * type = i.expr->result;
323
324	if ( auto bt = dynamic_cast< const ast::BasicType * >( type ) ) {
325	return bt->isInteger();
326	} else if (
327	dynamic_cast< const ast::EnumInstType * >( type )
328	\|\| dynamic_cast< const ast::ZeroType * >( type )
329	\|\| dynamic_cast< const ast::OneType * >( type )
330	) {
331	return true;
332	} else return false;
333	}
334
335	/// Resolve `untyped` as an integral expression, returning the resolved version
336	ast::ptr< ast::Expr > findIntegralExpression(
337	const ast::Expr * untyped, const ResolveContext & context
338	) {
339	return findKindExpression( untyped, context, hasIntegralType, "condition" );
340	}
341
342	/// check if a type is a character type
343	bool isCharType( const ast::Type * t ) {
344	if ( auto bt = dynamic_cast< const ast::BasicType * >( t ) ) {
345	return bt->kind == ast::BasicType::Char
346	\|\| bt->kind == ast::BasicType::SignedChar
347	\|\| bt->kind == ast::BasicType::UnsignedChar;
348	}
349	return false;
350	}
351
352	/// Advance a type itertor to the next mutex parameter
353	template<typename Iter>
354	inline bool nextMutex( Iter & it, const Iter & end ) {
355	while ( it != end && ! (*it)->is_mutex() ) { ++it; }
356	return it != end;
357	}
358	}
359
360	class Resolver final
361	: public ast::WithSymbolTable, public ast::WithGuards,
362	public ast::WithVisitorRef<Resolver>, public ast::WithShortCircuiting,
363	public ast::WithStmtsToAdd<> {
364
365	ast::ptr< ast::Type > functionReturn = nullptr;
366	ast::CurrentObject currentObject;
367	// for work previously in GenInit
368	static InitTweak::ManagedTypes managedTypes;
369	ResolveContext context;
370
371	bool inEnumDecl = false;
372
373	public:
374	static size_t traceId;
375	Resolver( const ast::TranslationGlobal & global ) :
376	ast::WithSymbolTable(ast::SymbolTable::ErrorDetection::ValidateOnAdd),
377	context{ symtab, global } {}
378	Resolver( const ResolveContext & context ) :
379	ast::WithSymbolTable{ context.symtab },
380	context{ symtab, context.global } {}
381
382	const ast::FunctionDecl * previsit( const ast::FunctionDecl * );
383	const ast::FunctionDecl * postvisit( const ast::FunctionDecl * );
384	const ast::ObjectDecl * previsit( const ast::ObjectDecl * );
385	void previsit( const ast::AggregateDecl * );
386	void previsit( const ast::StructDecl * );
387	void previsit( const ast::EnumDecl * );
388	const ast::StaticAssertDecl * previsit( const ast::StaticAssertDecl * );
389
390	const ast::ArrayType * previsit( const ast::ArrayType * );
391	const ast::PointerType * previsit( const ast::PointerType * );
392
393	const ast::ExprStmt * previsit( const ast::ExprStmt * );
394	const ast::AsmExpr * previsit( const ast::AsmExpr * );
395	const ast::AsmStmt * previsit( const ast::AsmStmt * );
396	const ast::IfStmt * previsit( const ast::IfStmt * );
397	const ast::WhileDoStmt * previsit( const ast::WhileDoStmt * );
398	const ast::ForStmt * previsit( const ast::ForStmt * );
399	const ast::SwitchStmt * previsit( const ast::SwitchStmt * );
400	const ast::CaseClause * previsit( const ast::CaseClause * );
401	const ast::BranchStmt * previsit( const ast::BranchStmt * );
402	const ast::ReturnStmt * previsit( const ast::ReturnStmt * );
403	const ast::ThrowStmt * previsit( const ast::ThrowStmt * );
404	const ast::CatchClause * previsit( const ast::CatchClause * );
405	const ast::CatchClause * postvisit( const ast::CatchClause * );
406	const ast::WaitForStmt * previsit( const ast::WaitForStmt * );
407	const ast::WithStmt * previsit( const ast::WithStmt * );
408
409	const ast::SingleInit * previsit( const ast::SingleInit * );
410	const ast::ListInit * previsit( const ast::ListInit * );
411	const ast::ConstructorInit * previsit( const ast::ConstructorInit * );
412
413	const ast::EnumPosExpr * previsit( const ast::EnumPosExpr * );
414
415	void resolveWithExprs(std::vector<ast::ptr<ast::Expr>> & exprs, std::list<ast::ptr<ast::Stmt>> & stmtsToAdd);
416
417	void beginScope() { managedTypes.beginScope(); }
418	void endScope() { managedTypes.endScope(); }
419	bool on_error(ast::ptr<ast::Decl> & decl);
420	};
421	// size_t Resolver::traceId = Stats::Heap::new_stacktrace_id("Resolver");
422
423	InitTweak::ManagedTypes Resolver::managedTypes;
424
425	void resolve( ast::TranslationUnit& translationUnit ) {
426	ast::Pass< Resolver >::run( translationUnit, translationUnit.global );
427	}
428
429	ast::ptr< ast::Init > resolveCtorInit(
430	const ast::ConstructorInit * ctorInit, const ResolveContext & context
431	) {
432	assert( ctorInit );
433	ast::Pass< Resolver > resolver( context );
434	return ctorInit->accept( resolver );
435	}
436
437	const ast::Expr * resolveStmtExpr(
438	const ast::StmtExpr * stmtExpr, const ResolveContext & context
439	) {
440	assert( stmtExpr );
441	ast::Pass< Resolver > resolver( context );
442	auto ret = mutate(stmtExpr->accept(resolver));
443	strict_dynamic_cast< ast::StmtExpr * >( ret )->computeResult();
444	return ret;
445	}
446
447	namespace {
448	const ast::Attribute * handleAttribute(const CodeLocation & loc, const ast::Attribute * attr, const ResolveContext & context) {
449	std::string name = attr->normalizedName();
450	if (name == "constructor" \|\| name == "destructor") {
451	if (attr->params.size() == 1) {
452	auto arg = attr->params.front();
453	auto resolved = ResolvExpr::findSingleExpression( arg, new ast::BasicType( ast::BasicType::LongLongSignedInt ), context );
454	auto result = eval(arg);
455
456	auto mutAttr = mutate(attr);
457	mutAttr->params.front() = resolved;
458	if (! result.hasKnownValue) {
459	SemanticWarning(loc, Warning::GccAttributes,
460	toCString( name, " priorities must be integers from 0 to 65535 inclusive: ", arg ) );
461	}
462	else {
463	auto priority = result.knownValue;
464	if (priority < 101) {
465	SemanticWarning(loc, Warning::GccAttributes,
466	toCString( name, " priorities from 0 to 100 are reserved for the implementation" ) );
467	} else if (priority < 201 && ! buildingLibrary()) {
468	SemanticWarning(loc, Warning::GccAttributes,
469	toCString( name, " priorities from 101 to 200 are reserved for the implementation" ) );
470	}
471	}
472	return mutAttr;
473	} else if (attr->params.size() > 1) {
474	SemanticWarning(loc, Warning::GccAttributes, toCString( "too many arguments to ", name, " attribute" ) );
475	} else {
476	SemanticWarning(loc, Warning::GccAttributes, toCString( "too few arguments to ", name, " attribute" ) );
477	}
478	}
479	return attr;
480	}
481	}
482
483	const ast::FunctionDecl * Resolver::previsit( const ast::FunctionDecl * functionDecl ) {
484	GuardValue( functionReturn );
485
486	assert (functionDecl->unique());
487	if (!functionDecl->has_body() && !functionDecl->withExprs.empty()) {
488	SemanticError(functionDecl->location, functionDecl, "Function without body has with declarations");
489	}
490
491	if (!functionDecl->isTypeFixed) {
492	auto mutDecl = mutate(functionDecl);
493	auto mutType = mutDecl->type.get_and_mutate();
494
495	for (auto & attr: mutDecl->attributes) {
496	attr = handleAttribute(mutDecl->location, attr, context );
497	}
498
499	// handle assertions
500
501	symtab.enterScope();
502	mutType->forall.clear();
503	mutType->assertions.clear();
504	for (auto & typeParam : mutDecl->type_params) {
505	symtab.addType(typeParam);
506	mutType->forall.emplace_back(new ast::TypeInstType(typeParam));
507	}
508	for (auto & asst : mutDecl->assertions) {
509	asst = fixObjectType(asst.strict_as<ast::ObjectDecl>(), context);
510	symtab.addId(asst);
511	mutType->assertions.emplace_back(new ast::VariableExpr(functionDecl->location, asst));
512	}
513
514	// temporarily adds params to symbol table.
515	// actual scoping rules for params and withexprs differ - see Pass::visit(FunctionDecl)
516
517	std::vector<ast::ptr<ast::Type>> paramTypes;
518	std::vector<ast::ptr<ast::Type>> returnTypes;
519
520	for (auto & param : mutDecl->params) {
521	param = fixObjectType(param.strict_as<ast::ObjectDecl>(), context);
522	symtab.addId(param);
523	paramTypes.emplace_back(param->get_type());
524	}
525	for (auto & ret : mutDecl->returns) {
526	ret = fixObjectType(ret.strict_as<ast::ObjectDecl>(), context);
527	returnTypes.emplace_back(ret->get_type());
528	}
529	// since function type in decl is just a view of param types, need to update that as well
530	mutType->params = std::move(paramTypes);
531	mutType->returns = std::move(returnTypes);
532
533	auto renamedType = strict_dynamic_cast<const ast::FunctionType *>(renameTyVars(mutType, RenameMode::GEN_EXPR_ID));
534
535	std::list<ast::ptr<ast::Stmt>> newStmts;
536	resolveWithExprs (mutDecl->withExprs, newStmts);
537
538	if (mutDecl->stmts) {
539	auto mutStmt = mutDecl->stmts.get_and_mutate();
540	mutStmt->kids.splice(mutStmt->kids.begin(), std::move(newStmts));
541	mutDecl->stmts = mutStmt;
542	}
543
544	symtab.leaveScope();
545
546	mutDecl->type = renamedType;
547	mutDecl->mangleName = Mangle::mangle(mutDecl);
548	mutDecl->isTypeFixed = true;
549	functionDecl = mutDecl;
550	}
551	managedTypes.handleDWT(functionDecl);
552
553	functionReturn = extractResultType( functionDecl->type );
554	return functionDecl;
555	}
556
557	const ast::FunctionDecl * Resolver::postvisit( const ast::FunctionDecl * functionDecl ) {
558	// default value expressions have an environment which shouldn't be there and trips up
559	// later passes.
560	assert( functionDecl->unique() );
561	ast::FunctionType * mutType = mutate( functionDecl->type.get() );
562
563	for ( unsigned i = 0 ; i < mutType->params.size() ; ++i ) {
564	if ( const ast::ObjectDecl * obj = mutType->params[i].as< ast::ObjectDecl >() ) {
565	if ( const ast::SingleInit * init = obj->init.as< ast::SingleInit >() ) {
566	if ( init->value->env == nullptr ) continue;
567	// clone initializer minus the initializer environment
568	auto mutParam = mutate( mutType->params[i].strict_as< ast::ObjectDecl >() );
569	auto mutInit = mutate( mutParam->init.strict_as< ast::SingleInit >() );
570	auto mutValue = mutate( mutInit->value.get() );
571
572	mutValue->env = nullptr;
573	mutInit->value = mutValue;
574	mutParam->init = mutInit;
575	mutType->params[i] = mutParam;
576
577	assert( ! mutType->params[i].strict_as< ast::ObjectDecl >()->init.strict_as< ast::SingleInit >()->value->env);
578	}
579	}
580	}
581	mutate_field(functionDecl, &ast::FunctionDecl::type, mutType);
582	return functionDecl;
583	}
584
585	const ast::ObjectDecl * Resolver::previsit( const ast::ObjectDecl * objectDecl ) {
586	// To handle initialization of routine pointers [e.g. int (*fp)(int) = foo()],
587	// class-variable `initContext` is changed multiple times because the LHS is analyzed
588	// twice. The second analysis changes `initContext` because a function type can contain
589	// object declarations in the return and parameter types. Therefore each value of
590	// `initContext` is retained so the type on the first analysis is preserved and used for
591	// selecting the RHS.
592	GuardValue( currentObject );
593
594	if ( inEnumDecl && dynamic_cast< const ast::EnumInstType * >( objectDecl->get_type() ) ) {
595	// enumerator initializers should not use the enum type to initialize, since the
596	// enum type is still incomplete at this point. Use `int` instead.
597
598	if ( auto enumBase = dynamic_cast< const ast::EnumInstType * >
599	( objectDecl->get_type() )->base->base ) {
600	objectDecl = fixObjectType( objectDecl, context );
601	currentObject = ast::CurrentObject{
602	objectDecl->location,
603	enumBase
604	};
605	} else {
606	objectDecl = fixObjectType( objectDecl, context );
607	currentObject = ast::CurrentObject{
608	objectDecl->location, new ast::BasicType{ ast::BasicType::SignedInt } };
609	}
610
611	}
612	else {
613	if ( !objectDecl->isTypeFixed ) {
614	auto newDecl = fixObjectType(objectDecl, context);
615	auto mutDecl = mutate(newDecl);
616
617	// generate CtorInit wrapper when necessary.
618	// in certain cases, fixObjectType is called before reaching
619	// this object in visitor pass, thus disabling CtorInit codegen.
620	// this happens on aggregate members and function parameters.
621	if ( InitTweak::tryConstruct( mutDecl ) && ( managedTypes.isManaged( mutDecl ) \|\| ((! isInFunction() \|\| mutDecl->storage.is_static ) && ! InitTweak::isConstExpr( mutDecl->init ) ) ) ) {
622	// constructed objects cannot be designated
623	if ( InitTweak::isDesignated( mutDecl->init ) ) {
624	ast::Pass<ResolveDesignators> res( context );
625	maybe_accept( mutDecl->init.get(), res );
626	if ( !res.core.result ) {
627	SemanticError( mutDecl, "Cannot include designations in the initializer for a managed Object.\n"
628	"If this is really what you want, initialize with @=." );
629	}
630	}
631	// constructed objects should not have initializers nested too deeply
632	if ( ! InitTweak::checkInitDepth( mutDecl ) ) SemanticError( mutDecl, "Managed object's initializer is too deep " );
633
634	mutDecl->init = InitTweak::genCtorInit( mutDecl->location, mutDecl );
635	}
636
637	objectDecl = mutDecl;
638	}
639	currentObject = ast::CurrentObject{ objectDecl->location, objectDecl->get_type() };
640	}
641
642	return objectDecl;
643	}
644
645	void Resolver::previsit( const ast::AggregateDecl * _aggDecl ) {
646	auto aggDecl = mutate(_aggDecl);
647	assertf(aggDecl == _aggDecl, "type declarations must be unique");
648
649	for (auto & member: aggDecl->members) {
650	// nested type decls are hoisted already. no need to do anything
651	if (auto obj = member.as<ast::ObjectDecl>()) {
652	member = fixObjectType(obj, context);
653	}
654	}
655	}
656
657	void Resolver::previsit( const ast::StructDecl * structDecl ) {
658	previsit(static_cast<const ast::AggregateDecl *>(structDecl));
659	managedTypes.handleStruct(structDecl);
660	}
661
662	void Resolver::previsit( const ast::EnumDecl * ) {
663	// in case we decide to allow nested enums
664	GuardValue( inEnumDecl );
665	inEnumDecl = true;
666	// don't need to fix types for enum fields
667	}
668
669	const ast::StaticAssertDecl * Resolver::previsit(
670	const ast::StaticAssertDecl * assertDecl
671	) {
672	return ast::mutate_field(
673	assertDecl, &ast::StaticAssertDecl::cond,
674	findIntegralExpression( assertDecl->cond, context ) );
675	}
676
677	template< typename PtrType >
678	const PtrType * handlePtrType( const PtrType * type, const ResolveContext & context ) {
679	if ( type->dimension ) {
680	const ast::Type * sizeType = context.global.sizeType.get();
681	ast::ptr< ast::Expr > dimension = findSingleExpression( type->dimension, sizeType, context );
682	assertf(dimension->env->empty(), "array dimension expr has nonempty env");
683	dimension.get_and_mutate()->env = nullptr;
684	ast::mutate_field( type, &PtrType::dimension, dimension );
685	}
686	return type;
687	}
688
689	const ast::ArrayType * Resolver::previsit( const ast::ArrayType * at ) {
690	return handlePtrType( at, context );
691	}
692
693	const ast::PointerType * Resolver::previsit( const ast::PointerType * pt ) {
694	return handlePtrType( pt, context );
695	}
696
697	const ast::ExprStmt * Resolver::previsit( const ast::ExprStmt * exprStmt ) {
698	visit_children = false;
699	assertf( exprStmt->expr, "ExprStmt has null expression in resolver" );
700
701	return ast::mutate_field(
702	exprStmt, &ast::ExprStmt::expr, findVoidExpression( exprStmt->expr, context ) );
703	}
704
705	const ast::AsmExpr * Resolver::previsit( const ast::AsmExpr * asmExpr ) {
706	visit_children = false;
707
708	asmExpr = ast::mutate_field(
709	asmExpr, &ast::AsmExpr::operand, findVoidExpression( asmExpr->operand, context ) );
710
711	return asmExpr;
712	}
713
714	const ast::AsmStmt * Resolver::previsit( const ast::AsmStmt * asmStmt ) {
715	visitor->maybe_accept( asmStmt, &ast::AsmStmt::input );
716	visitor->maybe_accept( asmStmt, &ast::AsmStmt::output );
717	visit_children = false;
718	return asmStmt;
719	}
720
721	const ast::IfStmt * Resolver::previsit( const ast::IfStmt * ifStmt ) {
722	return ast::mutate_field(
723	ifStmt, &ast::IfStmt::cond, findIntegralExpression( ifStmt->cond, context ) );
724	}
725
726	const ast::WhileDoStmt * Resolver::previsit( const ast::WhileDoStmt * whileDoStmt ) {
727	return ast::mutate_field(
728	whileDoStmt, &ast::WhileDoStmt::cond, findIntegralExpression( whileDoStmt->cond, context ) );
729	}
730
731	const ast::ForStmt * Resolver::previsit( const ast::ForStmt * forStmt ) {
732	if ( forStmt->cond ) {
733	forStmt = ast::mutate_field(
734	forStmt, &ast::ForStmt::cond, findIntegralExpression( forStmt->cond, context ) );
735	}
736
737	if ( forStmt->inc ) {
738	forStmt = ast::mutate_field(
739	forStmt, &ast::ForStmt::inc, findVoidExpression( forStmt->inc, context ) );
740	}
741
742	return forStmt;
743	}
744
745	const ast::SwitchStmt * Resolver::previsit( const ast::SwitchStmt * switchStmt ) {
746	GuardValue( currentObject );
747	switchStmt = ast::mutate_field(
748	switchStmt, &ast::SwitchStmt::cond,
749	findIntegralExpression( switchStmt->cond, context ) );
750	currentObject = ast::CurrentObject{ switchStmt->location, switchStmt->cond->result };
751	return switchStmt;
752	}
753
754	const ast::CaseClause * Resolver::previsit( const ast::CaseClause * caseStmt ) {
755	if ( caseStmt->cond ) {
756	std::deque< ast::InitAlternative > initAlts = currentObject.getOptions();
757	assertf( initAlts.size() == 1, "SwitchStmt did not correctly resolve an integral "
758	"expression." );
759
760	ast::ptr< ast::Expr > untyped =
761	new ast::CastExpr{ caseStmt->location, caseStmt->cond, initAlts.front().type };
762	ast::ptr< ast::Expr > newExpr = findSingleExpression( untyped, context );
763
764	// case condition cannot have a cast in C, so it must be removed here, regardless of
765	// whether it would perform a conversion.
766	if ( const ast::CastExpr * castExpr = newExpr.as< ast::CastExpr >() ) {
767	swap_and_save_env( newExpr, castExpr->arg );
768	}
769
770	caseStmt = ast::mutate_field( caseStmt, &ast::CaseClause::cond, newExpr );
771	}
772	return caseStmt;
773	}
774
775	const ast::BranchStmt * Resolver::previsit( const ast::BranchStmt * branchStmt ) {
776	visit_children = false;
777	// must resolve the argument of a computed goto
778	if ( branchStmt->kind == ast::BranchStmt::Goto && branchStmt->computedTarget ) {
779	// computed goto argument is void*
780	ast::ptr< ast::Type > target = new ast::PointerType{ new ast::VoidType{} };
781	branchStmt = ast::mutate_field(
782	branchStmt, &ast::BranchStmt::computedTarget,
783	findSingleExpression( branchStmt->computedTarget, target, context ) );
784	}
785	return branchStmt;
786	}
787
788	const ast::ReturnStmt * Resolver::previsit( const ast::ReturnStmt * returnStmt ) {
789	visit_children = false;
790	if ( returnStmt->expr ) {
791	returnStmt = ast::mutate_field(
792	returnStmt, &ast::ReturnStmt::expr,
793	findSingleExpression( returnStmt->expr, functionReturn, context ) );
794	}
795	return returnStmt;
796	}
797
798	const ast::ThrowStmt * Resolver::previsit( const ast::ThrowStmt * throwStmt ) {
799	visit_children = false;
800	if ( throwStmt->expr ) {
801	const ast::StructDecl * exceptionDecl =
802	symtab.lookupStruct( "__cfaehm_base_exception_t" );
803	assert( exceptionDecl );
804	ast::ptr< ast::Type > exceptType =
805	new ast::PointerType{ new ast::StructInstType{ exceptionDecl } };
806	throwStmt = ast::mutate_field(
807	throwStmt, &ast::ThrowStmt::expr,
808	findSingleExpression( throwStmt->expr, exceptType, context ) );
809	}
810	return throwStmt;
811	}
812
813	const ast::CatchClause * Resolver::previsit( const ast::CatchClause * catchClause ) {
814	// Until we are very sure this invarent (ifs that move between passes have then)
815	// holds, check it. This allows a check for when to decode the mangling.
816	if ( auto ifStmt = catchClause->body.as<ast::IfStmt>() ) {
817	assert( ifStmt->then );
818	}
819	// Encode the catchStmt so the condition can see the declaration.
820	if ( catchClause->cond ) {
821	ast::CatchClause * clause = mutate( catchClause );
822	clause->body = new ast::IfStmt( clause->location, clause->cond, nullptr, clause->body );
823	clause->cond = nullptr;
824	return clause;
825	}
826	return catchClause;
827	}
828
829	const ast::CatchClause * Resolver::postvisit( const ast::CatchClause * catchClause ) {
830	// Decode the catchStmt so everything is stored properly.
831	const ast::IfStmt * ifStmt = catchClause->body.as<ast::IfStmt>();
832	if ( nullptr != ifStmt && nullptr == ifStmt->then ) {
833	assert( ifStmt->cond );
834	assert( ifStmt->else_ );
835	ast::CatchClause * clause = ast::mutate( catchClause );
836	clause->cond = ifStmt->cond;
837	clause->body = ifStmt->else_;
838	// ifStmt should be implicately deleted here.
839	return clause;
840	}
841	return catchClause;
842	}
843
844	const ast::WaitForStmt * Resolver::previsit( const ast::WaitForStmt * stmt ) {
845	visit_children = false;
846
847	// Resolve all clauses first
848	for ( unsigned i = 0; i < stmt->clauses.size(); ++i ) {
849	const ast::WaitForClause & clause = *stmt->clauses[i];
850
851	ast::TypeEnvironment env;
852	CandidateFinder funcFinder( context, env );
853
854	// Find all candidates for a function in canonical form
855	funcFinder.find( clause.target, ResolveMode::withAdjustment() );
856
857	if ( funcFinder.candidates.empty() ) {
858	stringstream ss;
859	ss << "Use of undeclared indentifier '";
860	ss << clause.target.strict_as< ast::NameExpr >()->name;
861	ss << "' in call to waitfor";
862	SemanticError( stmt->location, ss.str() );
863	}
864
865	if ( clause.target_args.empty() ) {
866	SemanticError( stmt->location,
867	"Waitfor clause must have at least one mutex parameter");
868	}
869
870	// Find all alternatives for all arguments in canonical form
871	std::vector< CandidateFinder > argFinders =
872	funcFinder.findSubExprs( clause.target_args );
873
874	// List all combinations of arguments
875	std::vector< CandidateList > possibilities;
876	combos( argFinders.begin(), argFinders.end(), back_inserter( possibilities ) );
877
878	// For every possible function:
879	// * try matching the arguments to the parameters, not the other way around because
880	// more arguments than parameters
881	CandidateList funcCandidates;
882	std::vector< CandidateList > argsCandidates;
883	SemanticErrorException errors;
884	for ( CandidateRef & func : funcFinder.candidates ) {
885	try {
886	auto pointerType = dynamic_cast< const ast::PointerType * >(
887	func->expr->result->stripReferences() );
888	if ( ! pointerType ) {
889	SemanticError( stmt->location, func->expr->result.get(),
890	"candidate not viable: not a pointer type\n" );
891	}
892
893	auto funcType = pointerType->base.as< ast::FunctionType >();
894	if ( ! funcType ) {
895	SemanticError( stmt->location, func->expr->result.get(),
896	"candidate not viable: not a function type\n" );
897	}
898
899	{
900	auto param = funcType->params.begin();
901	auto paramEnd = funcType->params.end();
902
903	if( ! nextMutex( param, paramEnd ) ) {
904	SemanticError( stmt->location, funcType,
905	"candidate function not viable: no mutex parameters\n");
906	}
907	}
908
909	CandidateRef func2{ new Candidate{ *func } };
910	// strip reference from function
911	func2->expr = referenceToRvalueConversion( func->expr, func2->cost );
912
913	// Each argument must be matched with a parameter of the current candidate
914	for ( auto & argsList : possibilities ) {
915	try {
916	// Declare data structures needed for resolution
917	ast::OpenVarSet open;
918	ast::AssertionSet need, have;
919	ast::TypeEnvironment resultEnv{ func->env };
920	// Add all type variables as open so that those not used in the
921	// parameter list are still considered open
922	resultEnv.add( funcType->forall );
923
924	// load type variables from arguments into one shared space
925	for ( auto & arg : argsList ) {
926	resultEnv.simpleCombine( arg->env );
927	}
928
929	// Make sure we don't widen any existing bindings
930	resultEnv.forbidWidening();
931
932	// Find any unbound type variables
933	resultEnv.extractOpenVars( open );
934
935	auto param = funcType->params.begin();
936	auto paramEnd = funcType->params.end();
937
938	unsigned n_mutex_param = 0;
939
940	// For every argument of its set, check if it matches one of the
941	// parameters. The order is important
942	for ( auto & arg : argsList ) {
943	// Ignore non-mutex arguments
944	if ( ! nextMutex( param, paramEnd ) ) {
945	// We ran out of parameters but still have arguments.
946	// This function doesn't match
947	SemanticError( stmt->location, funcType,
948	toString("candidate function not viable: too many mutex "
949	"arguments, expected ", n_mutex_param, "\n" ) );
950	}
951
952	++n_mutex_param;
953
954	// Check if the argument matches the parameter type in the current scope.
955	// ast::ptr< ast::Type > paramType = (*param)->get_type();
956
957	if (
958	! unify(
959	arg->expr->result, *param, resultEnv, need, have, open )
960	) {
961	// Type doesn't match
962	stringstream ss;
963	ss << "candidate function not viable: no known conversion "
964	"from '";
965	ast::print( ss, *param );
966	ss << "' to '";
967	ast::print( ss, arg->expr->result );
968	ss << "' with env '";
969	ast::print( ss, resultEnv );
970	ss << "'\n";
971	SemanticError( stmt->location, funcType, ss.str() );
972	}
973
974	++param;
975	}
976
977	// All arguments match!
978
979	// Check if parameters are missing
980	if ( nextMutex( param, paramEnd ) ) {
981	do {
982	++n_mutex_param;
983	++param;
984	} while ( nextMutex( param, paramEnd ) );
985
986	// We ran out of arguments but still have parameters left; this
987	// function doesn't match
988	SemanticError( stmt->location, funcType,
989	toString( "candidate function not viable: too few mutex "
990	"arguments, expected ", n_mutex_param, "\n" ) );
991	}
992
993	// All parameters match!
994
995	// Finish the expressions to tie in proper environments
996	finishExpr( func2->expr, resultEnv );
997	for ( CandidateRef & arg : argsList ) {
998	finishExpr( arg->expr, resultEnv );
999	}
1000
1001	// This is a match, store it and save it for later
1002	funcCandidates.emplace_back( std::move( func2 ) );
1003	argsCandidates.emplace_back( std::move( argsList ) );
1004
1005	} catch ( SemanticErrorException & e ) {
1006	errors.append( e );
1007	}
1008	}
1009	} catch ( SemanticErrorException & e ) {
1010	errors.append( e );
1011	}
1012	}
1013
1014	// Make sure correct number of arguments
1015	if( funcCandidates.empty() ) {
1016	SemanticErrorException top( stmt->location,
1017	"No alternatives for function in call to waitfor" );
1018	top.append( errors );
1019	throw top;
1020	}
1021
1022	if( argsCandidates.empty() ) {
1023	SemanticErrorException top( stmt->location,
1024	"No alternatives for arguments in call to waitfor" );
1025	top.append( errors );
1026	throw top;
1027	}
1028
1029	if( funcCandidates.size() > 1 ) {
1030	SemanticErrorException top( stmt->location,
1031	"Ambiguous function in call to waitfor" );
1032	top.append( errors );
1033	throw top;
1034	}
1035	if( argsCandidates.size() > 1 ) {
1036	SemanticErrorException top( stmt->location,
1037	"Ambiguous arguments in call to waitfor" );
1038	top.append( errors );
1039	throw top;
1040	}
1041	// TODO: need to use findDeletedExpr to ensure no deleted identifiers are used.
1042
1043	// build new clause
1044	auto clause2 = new ast::WaitForClause( clause.location );
1045
1046	clause2->target = funcCandidates.front()->expr;
1047
1048	clause2->target_args.reserve( clause.target_args.size() );
1049	const ast::StructDecl * decl_monitor = symtab.lookupStruct( "monitor$" );
1050	for ( auto arg : argsCandidates.front() ) {
1051	const auto & loc = stmt->location;
1052
1053	ast::Expr * init = new ast::CastExpr( loc,
1054	new ast::UntypedExpr( loc,
1055	new ast::NameExpr( loc, "get_monitor" ),
1056	{ arg->expr }
1057	),
1058	new ast::PointerType(
1059	new ast::StructInstType(
1060	decl_monitor
1061	)
1062	)
1063	);
1064
1065	clause2->target_args.emplace_back( findSingleExpression( init, context ) );
1066	}
1067
1068	// Resolve the conditions as if it were an IfStmt, statements normally
1069	clause2->when_cond = findSingleExpression( clause.when_cond, context );
1070	clause2->stmt = clause.stmt->accept( *visitor );
1071
1072	// set results into stmt
1073	auto n = mutate( stmt );
1074	n->clauses[i] = clause2;
1075	stmt = n;
1076	}
1077
1078	if ( stmt->timeout_stmt ) {
1079	// resolve the timeout as a size_t, the conditions like IfStmt, and stmts normally
1080	ast::ptr< ast::Type > target =
1081	new ast::BasicType{ ast::BasicType::LongLongUnsignedInt };
1082	auto timeout_time = findSingleExpression( stmt->timeout_time, target, context );
1083	auto timeout_cond = findSingleExpression( stmt->timeout_cond, context );
1084	auto timeout_stmt = stmt->timeout_stmt->accept( *visitor );
1085
1086	// set results into stmt
1087	auto n = mutate( stmt );
1088	n->timeout_time = std::move( timeout_time );
1089	n->timeout_cond = std::move( timeout_cond );
1090	n->timeout_stmt = std::move( timeout_stmt );
1091	stmt = n;
1092	}
1093
1094	if ( stmt->else_stmt ) {
1095	// resolve the condition like IfStmt, stmts normally
1096	auto else_cond = findSingleExpression( stmt->else_cond, context );
1097	auto else_stmt = stmt->else_stmt->accept( *visitor );
1098
1099	// set results into stmt
1100	auto n = mutate( stmt );
1101	n->else_cond = std::move( else_cond );
1102	n->else_stmt = std::move( else_stmt );
1103	stmt = n;
1104	}
1105
1106	return stmt;
1107	}
1108
1109	const ast::WithStmt * Resolver::previsit( const ast::WithStmt * withStmt ) {
1110	auto mutStmt = mutate(withStmt);
1111	resolveWithExprs(mutStmt->exprs, stmtsToAddBefore);
1112	return mutStmt;
1113	}
1114
1115	void Resolver::resolveWithExprs(std::vector<ast::ptr<ast::Expr>> & exprs, std::list<ast::ptr<ast::Stmt>> & stmtsToAdd) {
1116	for (auto & expr : exprs) {
1117	// only struct- and union-typed expressions are viable candidates
1118	expr = findKindExpression( expr, context, structOrUnion, "with expression" );
1119
1120	// if with expression might be impure, create a temporary so that it is evaluated once
1121	if ( Tuples::maybeImpure( expr ) ) {
1122	static UniqueName tmpNamer( "_with_tmp_" );
1123	const CodeLocation loc = expr->location;
1124	auto tmp = new ast::ObjectDecl(loc, tmpNamer.newName(), expr->result, new ast::SingleInit(loc, expr ) );
1125	expr = new ast::VariableExpr( loc, tmp );
1126	stmtsToAdd.push_back( new ast::DeclStmt(loc, tmp ) );
1127	if ( InitTweak::isConstructable( tmp->type ) ) {
1128	// generate ctor/dtor and resolve them
1129	tmp->init = InitTweak::genCtorInit( loc, tmp );
1130	}
1131	// since tmp is freshly created, this should modify tmp in-place
1132	tmp->accept( *visitor );
1133	}
1134	else if (expr->env && expr->env->empty()) {
1135	expr = ast::mutate_field(expr.get(), &ast::Expr::env, nullptr);
1136	}
1137	}
1138	}
1139
1140
1141	const ast::SingleInit * Resolver::previsit( const ast::SingleInit * singleInit ) {
1142	visit_children = false;
1143	// resolve initialization using the possibilities as determined by the `currentObject`
1144	// cursor.
1145	ast::ptr< ast::Expr > untyped = new ast::UntypedInitExpr{
1146	singleInit->location, singleInit->value, currentObject.getOptions() };
1147	ast::ptr<ast::Expr> newExpr = findSingleExpression( untyped, context );
1148	const ast::InitExpr * initExpr = newExpr.strict_as< ast::InitExpr >();
1149
1150	// move cursor to the object that is actually initialized
1151	currentObject.setNext( initExpr->designation );
1152
1153	// discard InitExpr wrapper and retain relevant pieces.
1154	// `initExpr` may have inferred params in the case where the expression specialized a
1155	// function pointer, and newExpr may already have inferParams of its own, so a simple
1156	// swap is not sufficient
1157	ast::Expr::InferUnion inferred = initExpr->inferred;
1158	swap_and_save_env( newExpr, initExpr->expr );
1159	newExpr.get_and_mutate()->inferred.splice( std::move(inferred) );
1160
1161	// get the actual object's type (may not exactly match what comes back from the resolver
1162	// due to conversions)
1163	const ast::Type * initContext = currentObject.getCurrentType();
1164
1165	removeExtraneousCast( newExpr );
1166
1167	// check if actual object's type is char[]
1168	if ( auto at = dynamic_cast< const ast::ArrayType * >( initContext ) ) {
1169	if ( isCharType( at->base ) ) {
1170	// check if the resolved type is char*
1171	if ( auto pt = newExpr->result.as< ast::PointerType >() ) {
1172	if ( isCharType( pt->base ) ) {
1173	// strip cast if we're initializing a char[] with a char*
1174	// e.g. char x[] = "hello"
1175	if ( auto ce = newExpr.as< ast::CastExpr >() ) {
1176	swap_and_save_env( newExpr, ce->arg );
1177	}
1178	}
1179	}
1180	}
1181	}
1182
1183	// move cursor to next object in preparation for next initializer
1184	currentObject.increment();
1185
1186	// set initializer expression to resolved expression
1187	return ast::mutate_field( singleInit, &ast::SingleInit::value, std::move(newExpr) );
1188	}
1189
1190	const ast::ListInit * Resolver::previsit( const ast::ListInit * listInit ) {
1191	// move cursor into brace-enclosed initializer-list
1192	currentObject.enterListInit( listInit->location );
1193
1194	assert( listInit->designations.size() == listInit->initializers.size() );
1195	for ( unsigned i = 0; i < listInit->designations.size(); ++i ) {
1196	// iterate designations and initializers in pairs, moving the cursor to the current
1197	// designated object and resolving the initializer against that object
1198	listInit = ast::mutate_field_index(
1199	listInit, &ast::ListInit::designations, i,
1200	currentObject.findNext( listInit->designations[i] ) );
1201	listInit = ast::mutate_field_index(
1202	listInit, &ast::ListInit::initializers, i,
1203	listInit->initializers[i]->accept( *visitor ) );
1204	}
1205
1206	// move cursor out of brace-enclosed initializer-list
1207	currentObject.exitListInit();
1208
1209	visit_children = false;
1210	return listInit;
1211	}
1212
1213	const ast::ConstructorInit * Resolver::previsit( const ast::ConstructorInit * ctorInit ) {
1214	visitor->maybe_accept( ctorInit, &ast::ConstructorInit::ctor );
1215	visitor->maybe_accept( ctorInit, &ast::ConstructorInit::dtor );
1216
1217	// found a constructor - can get rid of C-style initializer
1218	// xxx - Rob suggests this field is dead code
1219	ctorInit = ast::mutate_field( ctorInit, &ast::ConstructorInit::init, nullptr );
1220
1221	// intrinsic single-parameter constructors and destructors do nothing. Since this was
1222	// implicitly generated, there's no way for it to have side effects, so get rid of it to
1223	// clean up generated code
1224	if ( InitTweak::isIntrinsicSingleArgCallStmt( ctorInit->ctor ) ) {
1225	ctorInit = ast::mutate_field( ctorInit, &ast::ConstructorInit::ctor, nullptr );
1226	}
1227	if ( InitTweak::isIntrinsicSingleArgCallStmt( ctorInit->dtor ) ) {
1228	ctorInit = ast::mutate_field( ctorInit, &ast::ConstructorInit::dtor, nullptr );
1229	}
1230
1231	return ctorInit;
1232	}
1233
1234	const ast::EnumPosExpr * Resolver::previsit( const ast::EnumPosExpr * enumPos ) {
1235	visitor->maybe_accept( enumPos, &ast::EnumPosExpr::expr );
1236	return enumPos;
1237	}
1238
1239	// suppress error on autogen functions and mark invalid autogen as deleted.
1240	bool Resolver::on_error(ast::ptr<ast::Decl> & decl) {
1241	if (auto functionDecl = decl.as<ast::FunctionDecl>()) {
1242	// xxx - can intrinsic gen ever fail?
1243	if (functionDecl->linkage == ast::Linkage::AutoGen) {
1244	auto mutDecl = mutate(functionDecl);
1245	mutDecl->isDeleted = true;
1246	mutDecl->stmts = nullptr;
1247	decl = mutDecl;
1248	return false;
1249	}
1250	}
1251	return true;
1252	}
1253
1254	} // namespace ResolvExpr
1255
1256	// Local Variables: //
1257	// tab-width: 4 //
1258	// mode: c++ //
1259	// compile-command: "make install" //
1260	// End: //

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