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source: src/ResolvExpr/Resolver.cc @ 36e120a

Last change on this file since 36e120a was 59c8dff, checked in by JiadaL <j82liang@…>, 6 months ago
Draft Implementation for enum position pesudo function (posE). EnumPosExpr? is mostly irrelevant for now. It is used in development/code probing and will be removed later
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File size: 45.0 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	template< typename iterator_t >
53	inline bool advance_to_mutex( iterator_t & it, const iterator_t & end ) {
54	while( it != end && !(*it)->get_type()->get_mutex() ) {
55	it++;
56	}
57
58	return it != end;
59	}
60
61	namespace {
62	/// Finds deleted expressions in an expression tree
63	struct DeleteFinder final : public ast::WithShortCircuiting, public ast::WithVisitorRef<DeleteFinder> {
64	const ast::DeletedExpr * result = nullptr;
65
66	void previsit( const ast::DeletedExpr * expr ) {
67	if ( result ) { visit_children = false; }
68	else { result = expr; }
69	}
70
71	void previsit( const ast::Expr * expr ) {
72	if ( result ) { visit_children = false; }
73	if (expr->inferred.hasParams()) {
74	for (auto & imp : expr->inferred.inferParams() ) {
75	imp.second.expr->accept(*visitor);
76	}
77	}
78	}
79	};
80
81	struct ResolveDesignators final : public ast::WithShortCircuiting {
82	ResolveContext& context;
83	bool result = false;
84
85	ResolveDesignators( ResolveContext& _context ): context{_context} {};
86
87	void previsit( const ast::Node * ) {
88	// short circuit if we already know there are designations
89	if ( result ) visit_children = false;
90	}
91
92	void previsit( const ast::Designation * des ) {
93	if ( result ) visit_children = false;
94	else if ( ! des->designators.empty() ) {
95	if ( (des->designators.size() == 1) ) {
96	const ast::Expr * designator = des->designators.at(0);
97	if ( const ast::NameExpr * designatorName = dynamic_cast<const ast::NameExpr *>(designator) ) {
98	auto candidates = context.symtab.lookupId(designatorName->name);
99	for ( auto candidate : candidates ) {
100	if ( dynamic_cast<const ast::EnumInstType *>(candidate.id->get_type()) ) {
101	result = true;
102	break;
103	}
104	}
105	}
106	}
107	visit_children = false;
108	}
109	}
110	};
111	} // anonymous namespace
112	/// Check if this expression is or includes a deleted expression
113	const ast::DeletedExpr * findDeletedExpr( const ast::Expr * expr ) {
114	return ast::Pass<DeleteFinder>::read( expr );
115	}
116
117	namespace {
118	/// always-accept candidate filter
119	bool anyCandidate( const Candidate & ) { return true; }
120
121	/// Calls the CandidateFinder and finds the single best candidate
122	CandidateRef findUnfinishedKindExpression(
123	const ast::Expr * untyped, const ResolveContext & context, const std::string & kind,
124	std::function<bool(const Candidate &)> pred = anyCandidate, ResolveMode mode = {}
125	) {
126	if ( ! untyped ) return nullptr;
127
128	// xxx - this isn't thread-safe, but should work until we parallelize the resolver
129	static unsigned recursion_level = 0;
130
131	++recursion_level;
132	ast::TypeEnvironment env;
133	CandidateFinder finder( context, env );
134	finder.allowVoid = true;
135	finder.find( untyped, recursion_level == 1 ? mode.atTopLevel() : mode );
136	--recursion_level;
137
138	// produce a filtered list of candidates
139	CandidateList candidates;
140	for ( auto & cand : finder.candidates ) {
141	if ( pred( *cand ) ) { candidates.emplace_back( cand ); }
142	}
143
144	// produce invalid error if no candidates
145	if ( candidates.empty() ) {
146	SemanticError( untyped,
147	toString( "No reasonable alternatives for ", kind, (kind != "" ? " " : ""),
148	"expression: ") );
149	}
150
151	// search for cheapest candidate
152	CandidateList winners;
153	bool seen_undeleted = false;
154	for ( CandidateRef & cand : candidates ) {
155	int c = winners.empty() ? -1 : cand->cost.compare( winners.front()->cost );
156
157	if ( c > 0 ) continue; // skip more expensive than winner
158
159	if ( c < 0 ) {
160	// reset on new cheapest
161	seen_undeleted = ! findDeletedExpr( cand->expr );
162	winners.clear();
163	} else /* if ( c == 0 ) */ {
164	if ( findDeletedExpr( cand->expr ) ) {
165	// skip deleted expression if already seen one equivalent-cost not
166	if ( seen_undeleted ) continue;
167	} else if ( ! seen_undeleted ) {
168	// replace list of equivalent-cost deleted expressions with one non-deleted
169	winners.clear();
170	seen_undeleted = true;
171	}
172	}
173
174	winners.emplace_back( std::move( cand ) );
175	}
176
177	// promote candidate.cvtCost to .cost
178	// promoteCvtCost( winners );
179
180	// produce ambiguous errors, if applicable
181	if ( winners.size() != 1 ) {
182	std::ostringstream stream;
183	stream << "Cannot choose between " << winners.size() << " alternatives for "
184	<< kind << (kind != "" ? " " : "") << "expression\n";
185	ast::print( stream, untyped );
186	stream << " Alternatives are:\n";
187	print( stream, winners, 1 );
188	SemanticError( untyped->location, stream.str() );
189	}
190
191	// single selected choice
192	CandidateRef & choice = winners.front();
193
194	// fail on only expression deleted
195	if ( ! seen_undeleted ) {
196	SemanticError( untyped->location, choice->expr.get(), "Unique best alternative "
197	"includes deleted identifier in " );
198	}
199
200	return std::move( choice );
201	}
202
203	/// Strips extraneous casts out of an expression
204	struct StripCasts final {
205	const ast::Expr * postvisit( const ast::CastExpr * castExpr ) {
206	if (
207	castExpr->isGenerated == ast::GeneratedCast
208	&& typesCompatible( castExpr->arg->result, castExpr->result )
209	) {
210	// generated cast is the same type as its argument, remove it after keeping env
211	return ast::mutate_field(
212	castExpr->arg.get(), &ast::Expr::env, castExpr->env );
213	}
214	return castExpr;
215	}
216
217	static void strip( ast::ptr< ast::Expr > & expr ) {
218	ast::Pass< StripCasts > stripper;
219	expr = expr->accept( stripper );
220	}
221	};
222
223	/// Swaps argument into expression pointer, saving original environment
224	void swap_and_save_env( ast::ptr< ast::Expr > & expr, const ast::Expr * newExpr ) {
225	ast::ptr< ast::TypeSubstitution > env = expr->env;
226	expr.set_and_mutate( newExpr )->env = env;
227	}
228
229	/// Removes cast to type of argument (unlike StripCasts, also handles non-generated casts)
230	void removeExtraneousCast( ast::ptr<ast::Expr> & expr ) {
231	if ( const ast::CastExpr * castExpr = expr.as< ast::CastExpr >() ) {
232	if ( typesCompatible( castExpr->arg->result, castExpr->result ) ) {
233	// cast is to the same type as its argument, remove it
234	swap_and_save_env( expr, castExpr->arg );
235	}
236	}
237	}
238
239
240	} // anonymous namespace
241	/// Establish post-resolver invariants for expressions
242	void finishExpr(
243	ast::ptr< ast::Expr > & expr, const ast::TypeEnvironment & env,
244	const ast::TypeSubstitution * oldenv = nullptr
245	) {
246	// set up new type substitution for expression
247	ast::ptr< ast::TypeSubstitution > newenv =
248	oldenv ? oldenv : new ast::TypeSubstitution{};
249	env.writeToSubstitution( *newenv.get_and_mutate() );
250	expr.get_and_mutate()->env = std::move( newenv );
251	// remove unncecessary casts
252	StripCasts::strip( expr );
253	}
254
255	ast::ptr< ast::Expr > resolveInVoidContext(
256	const ast::Expr * expr, const ResolveContext & context,
257	ast::TypeEnvironment & env
258	) {
259	assertf( expr, "expected a non-null expression" );
260
261	// set up and resolve expression cast to void
262	ast::ptr< ast::CastExpr > untyped = new ast::CastExpr{ expr };
263	CandidateRef choice = findUnfinishedKindExpression(
264	untyped, context, "", anyCandidate, ResolveMode::withAdjustment() );
265
266	// a cast expression has either 0 or 1 interpretations (by language rules);
267	// if 0, an exception has already been thrown, and this code will not run
268	const ast::CastExpr * castExpr = choice->expr.strict_as< ast::CastExpr >();
269	env = std::move( choice->env );
270
271	return castExpr->arg;
272	}
273
274	/// Resolve `untyped` to the expression whose candidate is the best match for a `void`
275	/// context.
276	ast::ptr< ast::Expr > findVoidExpression(
277	const ast::Expr * untyped, const ResolveContext & context
278	) {
279	ast::TypeEnvironment env;
280	ast::ptr< ast::Expr > newExpr = resolveInVoidContext( untyped, context, env );
281	finishExpr( newExpr, env, untyped->env );
282	return newExpr;
283	}
284
285	namespace {
286
287
288	/// resolve `untyped` to the expression whose candidate satisfies `pred` with the
289	/// lowest cost, returning the resolved version
290	ast::ptr< ast::Expr > findKindExpression(
291	const ast::Expr * untyped, const ResolveContext & context,
292	std::function<bool(const Candidate &)> pred = anyCandidate,
293	const std::string & kind = "", ResolveMode mode = {}
294	) {
295	if ( ! untyped ) return {};
296	CandidateRef choice =
297	findUnfinishedKindExpression( untyped, context, kind, pred, mode );
298	ResolvExpr::finishExpr( choice->expr, choice->env, untyped->env );
299	return std::move( choice->expr );
300	}
301
302	/// Resolve `untyped` to the single expression whose candidate is the best match
303	ast::ptr< ast::Expr > findSingleExpression(
304	const ast::Expr * untyped, const ResolveContext & context
305	) {
306	Stats::ResolveTime::start( untyped );
307	auto res = findKindExpression( untyped, context );
308	Stats::ResolveTime::stop();
309	return res;
310	}
311	} // anonymous namespace
312
313	ast::ptr< ast::Expr > findSingleExpression(
314	const ast::Expr * untyped, const ast::Type * type,
315	const ResolveContext & context
316	) {
317	assert( untyped && type );
318	ast::ptr< ast::Expr > castExpr = new ast::CastExpr{ untyped, type };
319	ast::ptr< ast::Expr > newExpr = findSingleExpression( castExpr, context );
320	removeExtraneousCast( newExpr );
321	return newExpr;
322	}
323
324	namespace {
325	bool structOrUnion( const Candidate & i ) {
326	const ast::Type * t = i.expr->result->stripReferences();
327	return dynamic_cast< const ast::StructInstType * >( t ) \|\| dynamic_cast< const ast::UnionInstType * >( t );
328	}
329	/// Predicate for "Candidate has integral type"
330	bool hasIntegralType( const Candidate & i ) {
331	const ast::Type * type = i.expr->result;
332
333	if ( auto bt = dynamic_cast< const ast::BasicType * >( type ) ) {
334	return bt->isInteger();
335	} else if (
336	dynamic_cast< const ast::EnumInstType * >( type )
337	\|\| dynamic_cast< const ast::ZeroType * >( type )
338	\|\| dynamic_cast< const ast::OneType * >( type )
339	) {
340	return true;
341	} else return false;
342	}
343
344	/// Resolve `untyped` as an integral expression, returning the resolved version
345	ast::ptr< ast::Expr > findIntegralExpression(
346	const ast::Expr * untyped, const ResolveContext & context
347	) {
348	return findKindExpression( untyped, context, hasIntegralType, "condition" );
349	}
350
351	/// check if a type is a character type
352	bool isCharType( const ast::Type * t ) {
353	if ( auto bt = dynamic_cast< const ast::BasicType * >( t ) ) {
354	return bt->kind == ast::BasicType::Char
355	\|\| bt->kind == ast::BasicType::SignedChar
356	\|\| bt->kind == ast::BasicType::UnsignedChar;
357	}
358	return false;
359	}
360
361	/// Advance a type itertor to the next mutex parameter
362	template<typename Iter>
363	inline bool nextMutex( Iter & it, const Iter & end ) {
364	while ( it != end && ! (*it)->is_mutex() ) { ++it; }
365	return it != end;
366	}
367	}
368
369	class Resolver final
370	: public ast::WithSymbolTable, public ast::WithGuards,
371	public ast::WithVisitorRef<Resolver>, public ast::WithShortCircuiting,
372	public ast::WithStmtsToAdd<> {
373
374	ast::ptr< ast::Type > functionReturn = nullptr;
375	ast::CurrentObject currentObject;
376	// for work previously in GenInit
377	static InitTweak::ManagedTypes managedTypes;
378	ResolveContext context;
379
380	bool inEnumDecl = false;
381
382	public:
383	static size_t traceId;
384	Resolver( const ast::TranslationGlobal & global ) :
385	ast::WithSymbolTable(ast::SymbolTable::ErrorDetection::ValidateOnAdd),
386	context{ symtab, global } {}
387	Resolver( const ResolveContext & context ) :
388	ast::WithSymbolTable{ context.symtab },
389	context{ symtab, context.global } {}
390
391	const ast::FunctionDecl * previsit( const ast::FunctionDecl * );
392	const ast::FunctionDecl * postvisit( const ast::FunctionDecl * );
393	const ast::ObjectDecl * previsit( const ast::ObjectDecl * );
394	void previsit( const ast::AggregateDecl * );
395	void previsit( const ast::StructDecl * );
396	void previsit( const ast::EnumDecl * );
397	const ast::StaticAssertDecl * previsit( const ast::StaticAssertDecl * );
398
399	const ast::ArrayType * previsit( const ast::ArrayType * );
400	const ast::PointerType * previsit( const ast::PointerType * );
401
402	const ast::ExprStmt * previsit( const ast::ExprStmt * );
403	const ast::AsmExpr * previsit( const ast::AsmExpr * );
404	const ast::AsmStmt * previsit( const ast::AsmStmt * );
405	const ast::IfStmt * previsit( const ast::IfStmt * );
406	const ast::WhileDoStmt * previsit( const ast::WhileDoStmt * );
407	const ast::ForStmt * previsit( const ast::ForStmt * );
408	const ast::SwitchStmt * previsit( const ast::SwitchStmt * );
409	const ast::CaseClause * previsit( const ast::CaseClause * );
410	const ast::BranchStmt * previsit( const ast::BranchStmt * );
411	const ast::ReturnStmt * previsit( const ast::ReturnStmt * );
412	const ast::ThrowStmt * previsit( const ast::ThrowStmt * );
413	const ast::CatchClause * previsit( const ast::CatchClause * );
414	const ast::CatchClause * postvisit( const ast::CatchClause * );
415	const ast::WaitForStmt * previsit( const ast::WaitForStmt * );
416	const ast::WithStmt * previsit( const ast::WithStmt * );
417
418	const ast::SingleInit * previsit( const ast::SingleInit * );
419	const ast::ListInit * previsit( const ast::ListInit * );
420	const ast::ConstructorInit * previsit( const ast::ConstructorInit * );
421
422	const ast::EnumPosExpr * previsit( const ast::EnumPosExpr * );
423
424	void resolveWithExprs(std::vector<ast::ptr<ast::Expr>> & exprs, std::list<ast::ptr<ast::Stmt>> & stmtsToAdd);
425
426	void beginScope() { managedTypes.beginScope(); }
427	void endScope() { managedTypes.endScope(); }
428	bool on_error(ast::ptr<ast::Decl> & decl);
429	};
430	// size_t Resolver::traceId = Stats::Heap::new_stacktrace_id("Resolver");
431
432	InitTweak::ManagedTypes Resolver::managedTypes;
433
434	void resolve( ast::TranslationUnit& translationUnit ) {
435	ast::Pass< Resolver >::run( translationUnit, translationUnit.global );
436	}
437
438	ast::ptr< ast::Init > resolveCtorInit(
439	const ast::ConstructorInit * ctorInit, const ResolveContext & context
440	) {
441	assert( ctorInit );
442	ast::Pass< Resolver > resolver( context );
443	return ctorInit->accept( resolver );
444	}
445
446	const ast::Expr * resolveStmtExpr(
447	const ast::StmtExpr * stmtExpr, const ResolveContext & context
448	) {
449	assert( stmtExpr );
450	ast::Pass< Resolver > resolver( context );
451	auto ret = mutate(stmtExpr->accept(resolver));
452	strict_dynamic_cast< ast::StmtExpr * >( ret )->computeResult();
453	return ret;
454	}
455
456	namespace {
457	const ast::Attribute * handleAttribute(const CodeLocation & loc, const ast::Attribute * attr, const ResolveContext & context) {
458	std::string name = attr->normalizedName();
459	if (name == "constructor" \|\| name == "destructor") {
460	if (attr->params.size() == 1) {
461	auto arg = attr->params.front();
462	auto resolved = ResolvExpr::findSingleExpression( arg, new ast::BasicType( ast::BasicType::LongLongSignedInt ), context );
463	auto result = eval(arg);
464
465	auto mutAttr = mutate(attr);
466	mutAttr->params.front() = resolved;
467	if (! result.hasKnownValue) {
468	SemanticWarning(loc, Warning::GccAttributes,
469	toCString( name, " priorities must be integers from 0 to 65535 inclusive: ", arg ) );
470	}
471	else {
472	auto priority = result.knownValue;
473	if (priority < 101) {
474	SemanticWarning(loc, Warning::GccAttributes,
475	toCString( name, " priorities from 0 to 100 are reserved for the implementation" ) );
476	} else if (priority < 201 && ! buildingLibrary()) {
477	SemanticWarning(loc, Warning::GccAttributes,
478	toCString( name, " priorities from 101 to 200 are reserved for the implementation" ) );
479	}
480	}
481	return mutAttr;
482	} else if (attr->params.size() > 1) {
483	SemanticWarning(loc, Warning::GccAttributes, toCString( "too many arguments to ", name, " attribute" ) );
484	} else {
485	SemanticWarning(loc, Warning::GccAttributes, toCString( "too few arguments to ", name, " attribute" ) );
486	}
487	}
488	return attr;
489	}
490	}
491
492	const ast::FunctionDecl * Resolver::previsit( const ast::FunctionDecl * functionDecl ) {
493	GuardValue( functionReturn );
494
495	assert (functionDecl->unique());
496	if (!functionDecl->has_body() && !functionDecl->withExprs.empty()) {
497	SemanticError(functionDecl->location, functionDecl, "Function without body has with declarations");
498	}
499
500	if (!functionDecl->isTypeFixed) {
501	auto mutDecl = mutate(functionDecl);
502	auto mutType = mutDecl->type.get_and_mutate();
503
504	for (auto & attr: mutDecl->attributes) {
505	attr = handleAttribute(mutDecl->location, attr, context );
506	}
507
508	// handle assertions
509
510	symtab.enterScope();
511	mutType->forall.clear();
512	mutType->assertions.clear();
513	for (auto & typeParam : mutDecl->type_params) {
514	symtab.addType(typeParam);
515	mutType->forall.emplace_back(new ast::TypeInstType(typeParam));
516	}
517	for (auto & asst : mutDecl->assertions) {
518	asst = fixObjectType(asst.strict_as<ast::ObjectDecl>(), context);
519	symtab.addId(asst);
520	mutType->assertions.emplace_back(new ast::VariableExpr(functionDecl->location, asst));
521	}
522
523	// temporarily adds params to symbol table.
524	// actual scoping rules for params and withexprs differ - see Pass::visit(FunctionDecl)
525
526	std::vector<ast::ptr<ast::Type>> paramTypes;
527	std::vector<ast::ptr<ast::Type>> returnTypes;
528
529	for (auto & param : mutDecl->params) {
530	param = fixObjectType(param.strict_as<ast::ObjectDecl>(), context);
531	symtab.addId(param);
532	paramTypes.emplace_back(param->get_type());
533	}
534	for (auto & ret : mutDecl->returns) {
535	ret = fixObjectType(ret.strict_as<ast::ObjectDecl>(), context);
536	returnTypes.emplace_back(ret->get_type());
537	}
538	// since function type in decl is just a view of param types, need to update that as well
539	mutType->params = std::move(paramTypes);
540	mutType->returns = std::move(returnTypes);
541
542	auto renamedType = strict_dynamic_cast<const ast::FunctionType *>(renameTyVars(mutType, RenameMode::GEN_EXPR_ID));
543
544	std::list<ast::ptr<ast::Stmt>> newStmts;
545	resolveWithExprs (mutDecl->withExprs, newStmts);
546
547	if (mutDecl->stmts) {
548	auto mutStmt = mutDecl->stmts.get_and_mutate();
549	mutStmt->kids.splice(mutStmt->kids.begin(), std::move(newStmts));
550	mutDecl->stmts = mutStmt;
551	}
552
553	symtab.leaveScope();
554
555	mutDecl->type = renamedType;
556	mutDecl->mangleName = Mangle::mangle(mutDecl);
557	mutDecl->isTypeFixed = true;
558	functionDecl = mutDecl;
559	}
560	managedTypes.handleDWT(functionDecl);
561
562	functionReturn = extractResultType( functionDecl->type );
563	return functionDecl;
564	}
565
566	const ast::FunctionDecl * Resolver::postvisit( const ast::FunctionDecl * functionDecl ) {
567	// default value expressions have an environment which shouldn't be there and trips up
568	// later passes.
569	assert( functionDecl->unique() );
570	ast::FunctionType * mutType = mutate( functionDecl->type.get() );
571
572	for ( unsigned i = 0 ; i < mutType->params.size() ; ++i ) {
573	if ( const ast::ObjectDecl * obj = mutType->params[i].as< ast::ObjectDecl >() ) {
574	if ( const ast::SingleInit * init = obj->init.as< ast::SingleInit >() ) {
575	if ( init->value->env == nullptr ) continue;
576	// clone initializer minus the initializer environment
577	auto mutParam = mutate( mutType->params[i].strict_as< ast::ObjectDecl >() );
578	auto mutInit = mutate( mutParam->init.strict_as< ast::SingleInit >() );
579	auto mutValue = mutate( mutInit->value.get() );
580
581	mutValue->env = nullptr;
582	mutInit->value = mutValue;
583	mutParam->init = mutInit;
584	mutType->params[i] = mutParam;
585
586	assert( ! mutType->params[i].strict_as< ast::ObjectDecl >()->init.strict_as< ast::SingleInit >()->value->env);
587	}
588	}
589	}
590	mutate_field(functionDecl, &ast::FunctionDecl::type, mutType);
591	return functionDecl;
592	}
593
594	const ast::ObjectDecl * Resolver::previsit( const ast::ObjectDecl * objectDecl ) {
595	// To handle initialization of routine pointers [e.g. int (*fp)(int) = foo()],
596	// class-variable `initContext` is changed multiple times because the LHS is analyzed
597	// twice. The second analysis changes `initContext` because a function type can contain
598	// object declarations in the return and parameter types. Therefore each value of
599	// `initContext` is retained so the type on the first analysis is preserved and used for
600	// selecting the RHS.
601	GuardValue( currentObject );
602
603	if ( inEnumDecl && dynamic_cast< const ast::EnumInstType * >( objectDecl->get_type() ) ) {
604	// enumerator initializers should not use the enum type to initialize, since the
605	// enum type is still incomplete at this point. Use `int` instead.
606
607	if ( auto enumBase = dynamic_cast< const ast::EnumInstType * >
608	( objectDecl->get_type() )->base->base ) {
609	objectDecl = fixObjectType( objectDecl, context );
610	currentObject = ast::CurrentObject{
611	objectDecl->location,
612	enumBase
613	};
614	} else {
615	objectDecl = fixObjectType( objectDecl, context );
616	currentObject = ast::CurrentObject{
617	objectDecl->location, new ast::BasicType{ ast::BasicType::SignedInt } };
618	}
619
620	}
621	else {
622	if ( !objectDecl->isTypeFixed ) {
623	auto newDecl = fixObjectType(objectDecl, context);
624	auto mutDecl = mutate(newDecl);
625
626	// generate CtorInit wrapper when necessary.
627	// in certain cases, fixObjectType is called before reaching
628	// this object in visitor pass, thus disabling CtorInit codegen.
629	// this happens on aggregate members and function parameters.
630	if ( InitTweak::tryConstruct( mutDecl ) && ( managedTypes.isManaged( mutDecl ) \|\| ((! isInFunction() \|\| mutDecl->storage.is_static ) && ! InitTweak::isConstExpr( mutDecl->init ) ) ) ) {
631	// constructed objects cannot be designated
632	if ( InitTweak::isDesignated( mutDecl->init ) ) {
633	ast::Pass<ResolveDesignators> res( context );
634	maybe_accept( mutDecl->init.get(), res );
635	if ( !res.core.result ) {
636	SemanticError( mutDecl, "Cannot include designations in the initializer for a managed Object.\n"
637	"If this is really what you want, initialize with @=." );
638	}
639	}
640	// constructed objects should not have initializers nested too deeply
641	if ( ! InitTweak::checkInitDepth( mutDecl ) ) SemanticError( mutDecl, "Managed object's initializer is too deep " );
642
643	mutDecl->init = InitTweak::genCtorInit( mutDecl->location, mutDecl );
644	}
645
646	objectDecl = mutDecl;
647	}
648	currentObject = ast::CurrentObject{ objectDecl->location, objectDecl->get_type() };
649	}
650
651	return objectDecl;
652	}
653
654	void Resolver::previsit( const ast::AggregateDecl * _aggDecl ) {
655	auto aggDecl = mutate(_aggDecl);
656	assertf(aggDecl == _aggDecl, "type declarations must be unique");
657
658	for (auto & member: aggDecl->members) {
659	// nested type decls are hoisted already. no need to do anything
660	if (auto obj = member.as<ast::ObjectDecl>()) {
661	member = fixObjectType(obj, context);
662	}
663	}
664	}
665
666	void Resolver::previsit( const ast::StructDecl * structDecl ) {
667	previsit(static_cast<const ast::AggregateDecl *>(structDecl));
668	managedTypes.handleStruct(structDecl);
669	}
670
671	void Resolver::previsit( const ast::EnumDecl * ) {
672	// in case we decide to allow nested enums
673	GuardValue( inEnumDecl );
674	inEnumDecl = true;
675	// don't need to fix types for enum fields
676	}
677
678	const ast::StaticAssertDecl * Resolver::previsit(
679	const ast::StaticAssertDecl * assertDecl
680	) {
681	return ast::mutate_field(
682	assertDecl, &ast::StaticAssertDecl::cond,
683	findIntegralExpression( assertDecl->cond, context ) );
684	}
685
686	template< typename PtrType >
687	const PtrType * handlePtrType( const PtrType * type, const ResolveContext & context ) {
688	if ( type->dimension ) {
689	const ast::Type * sizeType = context.global.sizeType.get();
690	ast::ptr< ast::Expr > dimension = findSingleExpression( type->dimension, sizeType, context );
691	assertf(dimension->env->empty(), "array dimension expr has nonempty env");
692	dimension.get_and_mutate()->env = nullptr;
693	ast::mutate_field( type, &PtrType::dimension, dimension );
694	}
695	return type;
696	}
697
698	const ast::ArrayType * Resolver::previsit( const ast::ArrayType * at ) {
699	return handlePtrType( at, context );
700	}
701
702	const ast::PointerType * Resolver::previsit( const ast::PointerType * pt ) {
703	return handlePtrType( pt, context );
704	}
705
706	const ast::ExprStmt * Resolver::previsit( const ast::ExprStmt * exprStmt ) {
707	visit_children = false;
708	assertf( exprStmt->expr, "ExprStmt has null expression in resolver" );
709
710	return ast::mutate_field(
711	exprStmt, &ast::ExprStmt::expr, findVoidExpression( exprStmt->expr, context ) );
712	}
713
714	const ast::AsmExpr * Resolver::previsit( const ast::AsmExpr * asmExpr ) {
715	visit_children = false;
716
717	asmExpr = ast::mutate_field(
718	asmExpr, &ast::AsmExpr::operand, findVoidExpression( asmExpr->operand, context ) );
719
720	return asmExpr;
721	}
722
723	const ast::AsmStmt * Resolver::previsit( const ast::AsmStmt * asmStmt ) {
724	visitor->maybe_accept( asmStmt, &ast::AsmStmt::input );
725	visitor->maybe_accept( asmStmt, &ast::AsmStmt::output );
726	visit_children = false;
727	return asmStmt;
728	}
729
730	const ast::IfStmt * Resolver::previsit( const ast::IfStmt * ifStmt ) {
731	return ast::mutate_field(
732	ifStmt, &ast::IfStmt::cond, findIntegralExpression( ifStmt->cond, context ) );
733	}
734
735	const ast::WhileDoStmt * Resolver::previsit( const ast::WhileDoStmt * whileDoStmt ) {
736	return ast::mutate_field(
737	whileDoStmt, &ast::WhileDoStmt::cond, findIntegralExpression( whileDoStmt->cond, context ) );
738	}
739
740	const ast::ForStmt * Resolver::previsit( const ast::ForStmt * forStmt ) {
741	if ( forStmt->cond ) {
742	forStmt = ast::mutate_field(
743	forStmt, &ast::ForStmt::cond, findIntegralExpression( forStmt->cond, context ) );
744	}
745
746	if ( forStmt->inc ) {
747	forStmt = ast::mutate_field(
748	forStmt, &ast::ForStmt::inc, findVoidExpression( forStmt->inc, context ) );
749	}
750
751	return forStmt;
752	}
753
754	const ast::SwitchStmt * Resolver::previsit( const ast::SwitchStmt * switchStmt ) {
755	GuardValue( currentObject );
756	switchStmt = ast::mutate_field(
757	switchStmt, &ast::SwitchStmt::cond,
758	findIntegralExpression( switchStmt->cond, context ) );
759	currentObject = ast::CurrentObject{ switchStmt->location, switchStmt->cond->result };
760	return switchStmt;
761	}
762
763	const ast::CaseClause * Resolver::previsit( const ast::CaseClause * caseStmt ) {
764	if ( caseStmt->cond ) {
765	std::deque< ast::InitAlternative > initAlts = currentObject.getOptions();
766	assertf( initAlts.size() == 1, "SwitchStmt did not correctly resolve an integral "
767	"expression." );
768
769	ast::ptr< ast::Expr > untyped =
770	new ast::CastExpr{ caseStmt->location, caseStmt->cond, initAlts.front().type };
771	ast::ptr< ast::Expr > newExpr = findSingleExpression( untyped, context );
772
773	// case condition cannot have a cast in C, so it must be removed here, regardless of
774	// whether it would perform a conversion.
775	if ( const ast::CastExpr * castExpr = newExpr.as< ast::CastExpr >() ) {
776	swap_and_save_env( newExpr, castExpr->arg );
777	}
778
779	caseStmt = ast::mutate_field( caseStmt, &ast::CaseClause::cond, newExpr );
780	}
781	return caseStmt;
782	}
783
784	const ast::BranchStmt * Resolver::previsit( const ast::BranchStmt * branchStmt ) {
785	visit_children = false;
786	// must resolve the argument of a computed goto
787	if ( branchStmt->kind == ast::BranchStmt::Goto && branchStmt->computedTarget ) {
788	// computed goto argument is void*
789	ast::ptr< ast::Type > target = new ast::PointerType{ new ast::VoidType{} };
790	branchStmt = ast::mutate_field(
791	branchStmt, &ast::BranchStmt::computedTarget,
792	findSingleExpression( branchStmt->computedTarget, target, context ) );
793	}
794	return branchStmt;
795	}
796
797	const ast::ReturnStmt * Resolver::previsit( const ast::ReturnStmt * returnStmt ) {
798	visit_children = false;
799	if ( returnStmt->expr ) {
800	returnStmt = ast::mutate_field(
801	returnStmt, &ast::ReturnStmt::expr,
802	findSingleExpression( returnStmt->expr, functionReturn, context ) );
803	}
804	return returnStmt;
805	}
806
807	const ast::ThrowStmt * Resolver::previsit( const ast::ThrowStmt * throwStmt ) {
808	visit_children = false;
809	if ( throwStmt->expr ) {
810	const ast::StructDecl * exceptionDecl =
811	symtab.lookupStruct( "__cfaehm_base_exception_t" );
812	assert( exceptionDecl );
813	ast::ptr< ast::Type > exceptType =
814	new ast::PointerType{ new ast::StructInstType{ exceptionDecl } };
815	throwStmt = ast::mutate_field(
816	throwStmt, &ast::ThrowStmt::expr,
817	findSingleExpression( throwStmt->expr, exceptType, context ) );
818	}
819	return throwStmt;
820	}
821
822	const ast::CatchClause * Resolver::previsit( const ast::CatchClause * catchClause ) {
823	// Until we are very sure this invarent (ifs that move between passes have then)
824	// holds, check it. This allows a check for when to decode the mangling.
825	if ( auto ifStmt = catchClause->body.as<ast::IfStmt>() ) {
826	assert( ifStmt->then );
827	}
828	// Encode the catchStmt so the condition can see the declaration.
829	if ( catchClause->cond ) {
830	ast::CatchClause * clause = mutate( catchClause );
831	clause->body = new ast::IfStmt( clause->location, clause->cond, nullptr, clause->body );
832	clause->cond = nullptr;
833	return clause;
834	}
835	return catchClause;
836	}
837
838	const ast::CatchClause * Resolver::postvisit( const ast::CatchClause * catchClause ) {
839	// Decode the catchStmt so everything is stored properly.
840	const ast::IfStmt * ifStmt = catchClause->body.as<ast::IfStmt>();
841	if ( nullptr != ifStmt && nullptr == ifStmt->then ) {
842	assert( ifStmt->cond );
843	assert( ifStmt->else_ );
844	ast::CatchClause * clause = ast::mutate( catchClause );
845	clause->cond = ifStmt->cond;
846	clause->body = ifStmt->else_;
847	// ifStmt should be implicately deleted here.
848	return clause;
849	}
850	return catchClause;
851	}
852
853	const ast::WaitForStmt * Resolver::previsit( const ast::WaitForStmt * stmt ) {
854	visit_children = false;
855
856	// Resolve all clauses first
857	for ( unsigned i = 0; i < stmt->clauses.size(); ++i ) {
858	const ast::WaitForClause & clause = *stmt->clauses[i];
859
860	ast::TypeEnvironment env;
861	CandidateFinder funcFinder( context, env );
862
863	// Find all candidates for a function in canonical form
864	funcFinder.find( clause.target, ResolveMode::withAdjustment() );
865
866	if ( funcFinder.candidates.empty() ) {
867	stringstream ss;
868	ss << "Use of undeclared indentifier '";
869	ss << clause.target.strict_as< ast::NameExpr >()->name;
870	ss << "' in call to waitfor";
871	SemanticError( stmt->location, ss.str() );
872	}
873
874	if ( clause.target_args.empty() ) {
875	SemanticError( stmt->location,
876	"Waitfor clause must have at least one mutex parameter");
877	}
878
879	// Find all alternatives for all arguments in canonical form
880	std::vector< CandidateFinder > argFinders =
881	funcFinder.findSubExprs( clause.target_args );
882
883	// List all combinations of arguments
884	std::vector< CandidateList > possibilities;
885	combos( argFinders.begin(), argFinders.end(), back_inserter( possibilities ) );
886
887	// For every possible function:
888	// * try matching the arguments to the parameters, not the other way around because
889	// more arguments than parameters
890	CandidateList funcCandidates;
891	std::vector< CandidateList > argsCandidates;
892	SemanticErrorException errors;
893	for ( CandidateRef & func : funcFinder.candidates ) {
894	try {
895	auto pointerType = dynamic_cast< const ast::PointerType * >(
896	func->expr->result->stripReferences() );
897	if ( ! pointerType ) {
898	SemanticError( stmt->location, func->expr->result.get(),
899	"candidate not viable: not a pointer type\n" );
900	}
901
902	auto funcType = pointerType->base.as< ast::FunctionType >();
903	if ( ! funcType ) {
904	SemanticError( stmt->location, func->expr->result.get(),
905	"candidate not viable: not a function type\n" );
906	}
907
908	{
909	auto param = funcType->params.begin();
910	auto paramEnd = funcType->params.end();
911
912	if( ! nextMutex( param, paramEnd ) ) {
913	SemanticError( stmt->location, funcType,
914	"candidate function not viable: no mutex parameters\n");
915	}
916	}
917
918	CandidateRef func2{ new Candidate{ *func } };
919	// strip reference from function
920	func2->expr = referenceToRvalueConversion( func->expr, func2->cost );
921
922	// Each argument must be matched with a parameter of the current candidate
923	for ( auto & argsList : possibilities ) {
924	try {
925	// Declare data structures needed for resolution
926	ast::OpenVarSet open;
927	ast::AssertionSet need, have;
928	ast::TypeEnvironment resultEnv{ func->env };
929	// Add all type variables as open so that those not used in the
930	// parameter list are still considered open
931	resultEnv.add( funcType->forall );
932
933	// load type variables from arguments into one shared space
934	for ( auto & arg : argsList ) {
935	resultEnv.simpleCombine( arg->env );
936	}
937
938	// Make sure we don't widen any existing bindings
939	resultEnv.forbidWidening();
940
941	// Find any unbound type variables
942	resultEnv.extractOpenVars( open );
943
944	auto param = funcType->params.begin();
945	auto paramEnd = funcType->params.end();
946
947	unsigned n_mutex_param = 0;
948
949	// For every argument of its set, check if it matches one of the
950	// parameters. The order is important
951	for ( auto & arg : argsList ) {
952	// Ignore non-mutex arguments
953	if ( ! nextMutex( param, paramEnd ) ) {
954	// We ran out of parameters but still have arguments.
955	// This function doesn't match
956	SemanticError( stmt->location, funcType,
957	toString("candidate function not viable: too many mutex "
958	"arguments, expected ", n_mutex_param, "\n" ) );
959	}
960
961	++n_mutex_param;
962
963	// Check if the argument matches the parameter type in the current scope.
964	// ast::ptr< ast::Type > paramType = (*param)->get_type();
965
966	if (
967	! unify(
968	arg->expr->result, *param, resultEnv, need, have, open )
969	) {
970	// Type doesn't match
971	stringstream ss;
972	ss << "candidate function not viable: no known conversion "
973	"from '";
974	ast::print( ss, *param );
975	ss << "' to '";
976	ast::print( ss, arg->expr->result );
977	ss << "' with env '";
978	ast::print( ss, resultEnv );
979	ss << "'\n";
980	SemanticError( stmt->location, funcType, ss.str() );
981	}
982
983	++param;
984	}
985
986	// All arguments match!
987
988	// Check if parameters are missing
989	if ( nextMutex( param, paramEnd ) ) {
990	do {
991	++n_mutex_param;
992	++param;
993	} while ( nextMutex( param, paramEnd ) );
994
995	// We ran out of arguments but still have parameters left; this
996	// function doesn't match
997	SemanticError( stmt->location, funcType,
998	toString( "candidate function not viable: too few mutex "
999	"arguments, expected ", n_mutex_param, "\n" ) );
1000	}
1001
1002	// All parameters match!
1003
1004	// Finish the expressions to tie in proper environments
1005	finishExpr( func2->expr, resultEnv );
1006	for ( CandidateRef & arg : argsList ) {
1007	finishExpr( arg->expr, resultEnv );
1008	}
1009
1010	// This is a match, store it and save it for later
1011	funcCandidates.emplace_back( std::move( func2 ) );
1012	argsCandidates.emplace_back( std::move( argsList ) );
1013
1014	} catch ( SemanticErrorException & e ) {
1015	errors.append( e );
1016	}
1017	}
1018	} catch ( SemanticErrorException & e ) {
1019	errors.append( e );
1020	}
1021	}
1022
1023	// Make sure correct number of arguments
1024	if( funcCandidates.empty() ) {
1025	SemanticErrorException top( stmt->location,
1026	"No alternatives for function in call to waitfor" );
1027	top.append( errors );
1028	throw top;
1029	}
1030
1031	if( argsCandidates.empty() ) {
1032	SemanticErrorException top( stmt->location,
1033	"No alternatives for arguments in call to waitfor" );
1034	top.append( errors );
1035	throw top;
1036	}
1037
1038	if( funcCandidates.size() > 1 ) {
1039	SemanticErrorException top( stmt->location,
1040	"Ambiguous function in call to waitfor" );
1041	top.append( errors );
1042	throw top;
1043	}
1044	if( argsCandidates.size() > 1 ) {
1045	SemanticErrorException top( stmt->location,
1046	"Ambiguous arguments in call to waitfor" );
1047	top.append( errors );
1048	throw top;
1049	}
1050	// TODO: need to use findDeletedExpr to ensure no deleted identifiers are used.
1051
1052	// build new clause
1053	auto clause2 = new ast::WaitForClause( clause.location );
1054
1055	clause2->target = funcCandidates.front()->expr;
1056
1057	clause2->target_args.reserve( clause.target_args.size() );
1058	const ast::StructDecl * decl_monitor = symtab.lookupStruct( "monitor$" );
1059	for ( auto arg : argsCandidates.front() ) {
1060	const auto & loc = stmt->location;
1061
1062	ast::Expr * init = new ast::CastExpr( loc,
1063	new ast::UntypedExpr( loc,
1064	new ast::NameExpr( loc, "get_monitor" ),
1065	{ arg->expr }
1066	),
1067	new ast::PointerType(
1068	new ast::StructInstType(
1069	decl_monitor
1070	)
1071	)
1072	);
1073
1074	clause2->target_args.emplace_back( findSingleExpression( init, context ) );
1075	}
1076
1077	// Resolve the conditions as if it were an IfStmt, statements normally
1078	clause2->when_cond = findSingleExpression( clause.when_cond, context );
1079	clause2->stmt = clause.stmt->accept( *visitor );
1080
1081	// set results into stmt
1082	auto n = mutate( stmt );
1083	n->clauses[i] = clause2;
1084	stmt = n;
1085	}
1086
1087	if ( stmt->timeout_stmt ) {
1088	// resolve the timeout as a size_t, the conditions like IfStmt, and stmts normally
1089	ast::ptr< ast::Type > target =
1090	new ast::BasicType{ ast::BasicType::LongLongUnsignedInt };
1091	auto timeout_time = findSingleExpression( stmt->timeout_time, target, context );
1092	auto timeout_cond = findSingleExpression( stmt->timeout_cond, context );
1093	auto timeout_stmt = stmt->timeout_stmt->accept( *visitor );
1094
1095	// set results into stmt
1096	auto n = mutate( stmt );
1097	n->timeout_time = std::move( timeout_time );
1098	n->timeout_cond = std::move( timeout_cond );
1099	n->timeout_stmt = std::move( timeout_stmt );
1100	stmt = n;
1101	}
1102
1103	if ( stmt->else_stmt ) {
1104	// resolve the condition like IfStmt, stmts normally
1105	auto else_cond = findSingleExpression( stmt->else_cond, context );
1106	auto else_stmt = stmt->else_stmt->accept( *visitor );
1107
1108	// set results into stmt
1109	auto n = mutate( stmt );
1110	n->else_cond = std::move( else_cond );
1111	n->else_stmt = std::move( else_stmt );
1112	stmt = n;
1113	}
1114
1115	return stmt;
1116	}
1117
1118	const ast::WithStmt * Resolver::previsit( const ast::WithStmt * withStmt ) {
1119	auto mutStmt = mutate(withStmt);
1120	resolveWithExprs(mutStmt->exprs, stmtsToAddBefore);
1121	return mutStmt;
1122	}
1123
1124	void Resolver::resolveWithExprs(std::vector<ast::ptr<ast::Expr>> & exprs, std::list<ast::ptr<ast::Stmt>> & stmtsToAdd) {
1125	for (auto & expr : exprs) {
1126	// only struct- and union-typed expressions are viable candidates
1127	expr = findKindExpression( expr, context, structOrUnion, "with expression" );
1128
1129	// if with expression might be impure, create a temporary so that it is evaluated once
1130	if ( Tuples::maybeImpure( expr ) ) {
1131	static UniqueName tmpNamer( "_with_tmp_" );
1132	const CodeLocation loc = expr->location;
1133	auto tmp = new ast::ObjectDecl(loc, tmpNamer.newName(), expr->result, new ast::SingleInit(loc, expr ) );
1134	expr = new ast::VariableExpr( loc, tmp );
1135	stmtsToAdd.push_back( new ast::DeclStmt(loc, tmp ) );
1136	if ( InitTweak::isConstructable( tmp->type ) ) {
1137	// generate ctor/dtor and resolve them
1138	tmp->init = InitTweak::genCtorInit( loc, tmp );
1139	}
1140	// since tmp is freshly created, this should modify tmp in-place
1141	tmp->accept( *visitor );
1142	}
1143	else if (expr->env && expr->env->empty()) {
1144	expr = ast::mutate_field(expr.get(), &ast::Expr::env, nullptr);
1145	}
1146	}
1147	}
1148
1149
1150	const ast::SingleInit * Resolver::previsit( const ast::SingleInit * singleInit ) {
1151	visit_children = false;
1152	// resolve initialization using the possibilities as determined by the `currentObject`
1153	// cursor.
1154	ast::ptr< ast::Expr > untyped = new ast::UntypedInitExpr{
1155	singleInit->location, singleInit->value, currentObject.getOptions() };
1156	ast::ptr<ast::Expr> newExpr = findSingleExpression( untyped, context );
1157	const ast::InitExpr * initExpr = newExpr.strict_as< ast::InitExpr >();
1158
1159	// move cursor to the object that is actually initialized
1160	currentObject.setNext( initExpr->designation );
1161
1162	// discard InitExpr wrapper and retain relevant pieces.
1163	// `initExpr` may have inferred params in the case where the expression specialized a
1164	// function pointer, and newExpr may already have inferParams of its own, so a simple
1165	// swap is not sufficient
1166	ast::Expr::InferUnion inferred = initExpr->inferred;
1167	swap_and_save_env( newExpr, initExpr->expr );
1168	newExpr.get_and_mutate()->inferred.splice( std::move(inferred) );
1169
1170	// get the actual object's type (may not exactly match what comes back from the resolver
1171	// due to conversions)
1172	const ast::Type * initContext = currentObject.getCurrentType();
1173
1174	removeExtraneousCast( newExpr );
1175
1176	// check if actual object's type is char[]
1177	if ( auto at = dynamic_cast< const ast::ArrayType * >( initContext ) ) {
1178	if ( isCharType( at->base ) ) {
1179	// check if the resolved type is char*
1180	if ( auto pt = newExpr->result.as< ast::PointerType >() ) {
1181	if ( isCharType( pt->base ) ) {
1182	// strip cast if we're initializing a char[] with a char*
1183	// e.g. char x[] = "hello"
1184	if ( auto ce = newExpr.as< ast::CastExpr >() ) {
1185	swap_and_save_env( newExpr, ce->arg );
1186	}
1187	}
1188	}
1189	}
1190	}
1191
1192	// move cursor to next object in preparation for next initializer
1193	currentObject.increment();
1194
1195	// set initializer expression to resolved expression
1196	return ast::mutate_field( singleInit, &ast::SingleInit::value, std::move(newExpr) );
1197	}
1198
1199	const ast::ListInit * Resolver::previsit( const ast::ListInit * listInit ) {
1200	// move cursor into brace-enclosed initializer-list
1201	currentObject.enterListInit( listInit->location );
1202
1203	assert( listInit->designations.size() == listInit->initializers.size() );
1204	for ( unsigned i = 0; i < listInit->designations.size(); ++i ) {
1205	// iterate designations and initializers in pairs, moving the cursor to the current
1206	// designated object and resolving the initializer against that object
1207	listInit = ast::mutate_field_index(
1208	listInit, &ast::ListInit::designations, i,
1209	currentObject.findNext( listInit->designations[i] ) );
1210	listInit = ast::mutate_field_index(
1211	listInit, &ast::ListInit::initializers, i,
1212	listInit->initializers[i]->accept( *visitor ) );
1213	}
1214
1215	// move cursor out of brace-enclosed initializer-list
1216	currentObject.exitListInit();
1217
1218	visit_children = false;
1219	return listInit;
1220	}
1221
1222	const ast::ConstructorInit * Resolver::previsit( const ast::ConstructorInit * ctorInit ) {
1223	visitor->maybe_accept( ctorInit, &ast::ConstructorInit::ctor );
1224	visitor->maybe_accept( ctorInit, &ast::ConstructorInit::dtor );
1225
1226	// found a constructor - can get rid of C-style initializer
1227	// xxx - Rob suggests this field is dead code
1228	ctorInit = ast::mutate_field( ctorInit, &ast::ConstructorInit::init, nullptr );
1229
1230	// intrinsic single-parameter constructors and destructors do nothing. Since this was
1231	// implicitly generated, there's no way for it to have side effects, so get rid of it to
1232	// clean up generated code
1233	if ( InitTweak::isIntrinsicSingleArgCallStmt( ctorInit->ctor ) ) {
1234	ctorInit = ast::mutate_field( ctorInit, &ast::ConstructorInit::ctor, nullptr );
1235	}
1236	if ( InitTweak::isIntrinsicSingleArgCallStmt( ctorInit->dtor ) ) {
1237	ctorInit = ast::mutate_field( ctorInit, &ast::ConstructorInit::dtor, nullptr );
1238	}
1239
1240	return ctorInit;
1241	}
1242
1243	const ast::EnumPosExpr * Resolver::previsit( const ast::EnumPosExpr * enumPos ) {
1244	visitor->maybe_accept( enumPos, &ast::EnumPosExpr::expr );
1245	return enumPos;
1246	}
1247
1248	// suppress error on autogen functions and mark invalid autogen as deleted.
1249	bool Resolver::on_error(ast::ptr<ast::Decl> & decl) {
1250	if (auto functionDecl = decl.as<ast::FunctionDecl>()) {
1251	// xxx - can intrinsic gen ever fail?
1252	if (functionDecl->linkage == ast::Linkage::AutoGen) {
1253	auto mutDecl = mutate(functionDecl);
1254	mutDecl->isDeleted = true;
1255	mutDecl->stmts = nullptr;
1256	decl = mutDecl;
1257	return false;
1258	}
1259	}
1260	return true;
1261	}
1262
1263	} // namespace ResolvExpr
1264
1265	// Local Variables: //
1266	// tab-width: 4 //
1267	// mode: c++ //
1268	// compile-command: "make install" //
1269	// End: //

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