source: src/InitTweak/FixInitNew.cpp@ 490fb92e

ADT arm-eh ast-experimental enum forall-pointer-decay jacob/cs343-translation new-ast-unique-expr pthread-emulation qualifiedEnum stuck-waitfor-destruct
Last change on this file since 490fb92e was 490fb92e, checked in by Fangren Yu <f37yu@…>, 5 years ago

move FixInit to new ast
  • Property mode set to 100644
File size: 61.5 KB
Line 
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// FixInit.cc --
8//
9// Author : Rob Schluntz
10// Created On : Wed Jan 13 16:29:30 2016
11// Last Modified By : Peter A. Buhr
12// Last Modified On : Sun Feb 16 04:17:07 2020
13// Update Count : 82
14//
15#include "FixInit.h"
16
17#include <stddef.h> // for NULL
18#include <algorithm> // for set_difference, copy_if
19#include <cassert> // for assert, strict_dynamic_cast
20#include <iostream> // for operator<<, ostream, basic_ost...
21#include <iterator> // for insert_iterator, back_inserter
22#include <list> // for _List_iterator, list, list<>::...
23#include <map> // for _Rb_tree_iterator, _Rb_tree_co...
24#include <memory> // for allocator_traits<>::value_type
25#include <set> // for set, set<>::value_type
26#include <unordered_map> // for unordered_map, unordered_map<>...
27#include <unordered_set> // for unordered_set
28#include <utility> // for pair
29
30#include "CodeGen/GenType.h" // for genPrettyType
31#include "CodeGen/OperatorTable.h"
32#include "Common/PassVisitor.h" // for PassVisitor, WithStmtsToAdd
33#include "Common/SemanticError.h" // for SemanticError
34#include "Common/UniqueName.h" // for UniqueName
35#include "Common/utility.h" // for CodeLocation, ValueGuard, toSt...
36#include "FixGlobalInit.h" // for fixGlobalInit
37#include "GenInit.h" // for genCtorDtor
38#include "GenPoly/GenPoly.h" // for getFunctionType
39#include "InitTweak.h" // for getFunctionName, getCallArg
40#include "ResolvExpr/Resolver.h" // for findVoidExpression
41#include "ResolvExpr/typeops.h" // for typesCompatible
42#include "SymTab/Autogen.h" // for genImplicitCall
43#include "SymTab/Indexer.h" // for Indexer
44#include "SymTab/Mangler.h" // for Mangler
45#include "SynTree/LinkageSpec.h" // for C, Spec, Cforall, isBuiltin
46#include "SynTree/Attribute.h" // for Attribute
47#include "SynTree/Constant.h" // for Constant
48#include "SynTree/Declaration.h" // for ObjectDecl, FunctionDecl, Decl...
49#include "SynTree/Expression.h" // for UniqueExpr, VariableExpr, Unty...
50#include "SynTree/Initializer.h" // for ConstructorInit, SingleInit
51#include "SynTree/Label.h" // for Label, operator<
52#include "SynTree/Mutator.h" // for mutateAll, Mutator, maybeMutate
53#include "SynTree/Statement.h" // for ExprStmt, CompoundStmt, Branch...
54#include "SynTree/Type.h" // for Type, Type::StorageClasses
55#include "SynTree/TypeSubstitution.h" // for TypeSubstitution, operator<<
56#include "SynTree/DeclReplacer.h" // for DeclReplacer
57#include "SynTree/Visitor.h" // for acceptAll, maybeAccept
58#include "Validate/FindSpecialDecls.h" // for dtorStmt, dtorStructDestroy
59
60#include "AST/Expr.hpp"
61#include "AST/Node.hpp"
62#include "AST/Pass.hpp"
63#include "AST/Print.hpp"
64#include "AST/SymbolTable.hpp"
65#include "AST/Type.hpp"
66#include "AST/DeclReplacer.hpp"
67
68extern bool ctordtorp; // print all debug
69extern bool ctorp; // print ctor debug
70extern bool cpctorp; // print copy ctor debug
71extern bool dtorp; // print dtor debug
72#define PRINT( text ) if ( ctordtorp ) { text }
73#define CP_CTOR_PRINT( text ) if ( ctordtorp || cpctorp ) { text }
74#define DTOR_PRINT( text ) if ( ctordtorp || dtorp ) { text }
75
76namespace InitTweak {
77 namespace {
78 struct SelfAssignChecker {
79 void previsit( const ast::ApplicationExpr * appExpr );
80 };
81
82 struct StmtExprResult {
83 static void link( std::list<ast::ptr<ast::Decl> > & translationUnit );
84
85 const ast::StmtExpr * previsit( const ast::StmtExpr * stmtExpr );
86 };
87
88 struct InsertImplicitCalls : public ast::WithConstTypeSubstitution, public ast::WithShortCircuiting {
89 /// wrap function application expressions as ImplicitCopyCtorExpr nodes so that it is easy to identify which
90 /// function calls need their parameters to be copy constructed
91 static void insert( std::list<ast::ptr<ast::Decl> > & translationUnit );
92
93 const ast::Expr * postvisit( const ast::ApplicationExpr * appExpr );
94
95 // only handles each UniqueExpr once
96 // if order of visit does not change, this should be safe
97 void previsit (const ast::UniqueExpr *);
98
99 std::unordered_set<decltype(ast::UniqueExpr::id)> visitedIds;
100 };
101
102 struct ResolveCopyCtors final : public ast::WithGuards, public ast::WithStmtsToAdd<>, public ast::WithSymbolTable, public ast::WithShortCircuiting, public ast::WithVisitorRef<ResolveCopyCtors> {
103 /// generate temporary ObjectDecls for each argument and return value of each ImplicitCopyCtorExpr,
104 /// generate/resolve copy construction expressions for each, and generate/resolve destructors for both
105 /// arguments and return value temporaries
106 static void resolveImplicitCalls( std::list<ast::ptr<ast::Decl> > & translationUnit );
107
108 const ast::Expr * postvisit( const ast::ImplicitCopyCtorExpr * impCpCtorExpr );
109 const ast::StmtExpr * previsit( const ast::StmtExpr * stmtExpr );
110 const ast::UniqueExpr * previsit( const ast::UniqueExpr * unqExpr );
111
112 /// handles distant mutations of environment manually.
113 /// WithConstTypeSubstitution cannot remember where the environment is from
114
115 /// MUST be called at start of overload previsit
116 void previsit( const ast::Expr * expr);
117 /// MUST be called at return of overload postvisit
118 const ast::Expr * postvisit(const ast::Expr * expr);
119
120 /// create and resolve ctor/dtor expression: fname(var, [cpArg])
121 const ast::Expr * makeCtorDtor( const std::string & fname, const ast::ObjectDecl * var, const ast::Expr * cpArg = nullptr );
122 /// true if type does not need to be copy constructed to ensure correctness
123 bool skipCopyConstruct( const ast::Type * type );
124 ast::ptr< ast::Expr > copyConstructArg( const ast::Expr * arg, const ast::ImplicitCopyCtorExpr * impCpCtorExpr, const ast::Type * formal );
125 ast::Expr * destructRet( const ast::ObjectDecl * ret, const ast::Expr * arg );
126 private:
127 /// hack to implement WithTypeSubstitution while conforming to mutation safety.
128 ast::TypeSubstitution * env;
129 bool envModified;
130 };
131
132 /// collects constructed object decls - used as a base class
133 struct ObjDeclCollector : public ast::WithGuards, public ast::WithShortCircuiting {
134 // use ordered data structure to maintain ordering for set_difference and for consistent error messages
135 typedef std::list< const ast::ObjectDecl * > ObjectSet;
136 void previsit( const ast::CompoundStmt *compoundStmt );
137 void previsit( const ast::DeclStmt *stmt );
138
139 // don't go into other functions
140 void previsit( const ast::FunctionDecl * ) { visit_children = false; }
141
142 protected:
143 ObjectSet curVars;
144 };
145
146 // debug
147 template<typename ObjectSet>
148 struct PrintSet {
149 PrintSet( const ObjectSet & objs ) : objs( objs ) {}
150 const ObjectSet & objs;
151 };
152 template<typename ObjectSet>
153 PrintSet<ObjectSet> printSet( const ObjectSet & objs ) { return PrintSet<ObjectSet>( objs ); }
154 template<typename ObjectSet>
155 std::ostream & operator<<( std::ostream & out, const PrintSet<ObjectSet> & set) {
156 out << "{ ";
157 for ( auto & obj : set.objs ) {
158 out << obj->name << ", " ;
159 } // for
160 out << " }";
161 return out;
162 }
163
164 struct LabelFinder final : public ObjDeclCollector {
165 typedef std::map< std::string, ObjectSet > LabelMap;
166 // map of Label -> live variables at that label
167 LabelMap vars;
168
169 typedef ObjDeclCollector Parent;
170 using Parent::previsit;
171 void previsit( const ast::Stmt * stmt );
172
173 void previsit( const ast::CompoundStmt *compoundStmt );
174 void previsit( const ast::DeclStmt *stmt );
175 };
176
177 struct InsertDtors final : public ObjDeclCollector, public ast::WithStmtsToAdd<> {
178 /// insert destructor calls at the appropriate places. must happen before CtorInit nodes are removed
179 /// (currently by FixInit)
180 static void insert( std::list< ast::ptr<ast::Decl> > & translationUnit );
181
182 typedef std::list< ObjectDecl * > OrderedDecls;
183 typedef std::list< OrderedDecls > OrderedDeclsStack;
184
185 InsertDtors( ast::Pass<LabelFinder> & finder ) : finder( finder ), labelVars( finder.core.vars ) {}
186
187 typedef ObjDeclCollector Parent;
188 using Parent::previsit;
189
190 void previsit( const ast::FunctionDecl * funcDecl );
191
192 void previsit( const ast::BranchStmt * stmt );
193 private:
194 void handleGoto( const ast::BranchStmt * stmt );
195
196 ast::Pass<LabelFinder> & finder;
197 LabelFinder::LabelMap & labelVars;
198 OrderedDeclsStack reverseDeclOrder;
199 };
200
201 class FixInit : public ast::WithStmtsToAdd<> {
202 public:
203 /// expand each object declaration to use its constructor after it is declared.
204 static void fixInitializers( std::list< ast::ptr<ast::Decl> > &translationUnit );
205
206 const ast::DeclWithType * postvisit( const ast::ObjectDecl *objDecl );
207
208 std::list< ast::ptr< ast::Decl > > staticDtorDecls;
209 };
210
211 struct GenStructMemberCalls final : public ast::WithGuards, public ast::WithShortCircuiting, public ast::WithSymbolTable, public ast::WithVisitorRef<GenStructMemberCalls> {
212 /// generate default/copy ctor and dtor calls for user-defined struct ctor/dtors
213 /// for any member that is missing a corresponding ctor/dtor call.
214 /// error if a member is used before constructed
215 static void generate( std::list< ast::ptr<ast::Decl> > & translationUnit );
216
217 void previsit( const ast::FunctionDecl * funcDecl );
218 const ast::DeclWithType * postvisit( const ast::FunctionDecl * funcDecl );
219
220 void previsit( const ast::MemberExpr * memberExpr );
221 void previsit( const ast::ApplicationExpr * appExpr );
222
223 /// Note: this post mutate used to be in a separate visitor. If this pass breaks, one place to examine is whether it is
224 /// okay for this part of the recursion to occur alongside the rest.
225 const ast::Expr * postvisit( const ast::UntypedExpr * expr );
226
227 SemanticErrorException errors;
228 private:
229 template< typename... Params >
230 void emit( CodeLocation, const Params &... params );
231
232 ast::FunctionDecl * function = nullptr;
233 std::set< const ast::DeclWithType * > unhandled;
234 std::map< const ast::DeclWithType *, CodeLocation > usedUninit;
235 const ast::ObjectDecl * thisParam = nullptr;
236 bool isCtor = false; // true if current function is a constructor
237 const ast::StructDecl * structDecl = nullptr;
238 };
239
240 struct FixCtorExprs final : public ast::WithDeclsToAdd<>, public ast::WithSymbolTable, public ast::WithShortCircuiting {
241 /// expands ConstructorExpr nodes into comma expressions, using a temporary for the first argument
242 static void fix( std::list< ast::ptr<ast::Decl> > & translationUnit );
243
244 const ast::Expr * postvisit( const ast::ConstructorExpr * ctorExpr );
245 };
246
247 struct SplitExpressions : public ast::WithShortCircuiting {
248 /// add CompoundStmts around top-level expressions so that temporaries are destroyed in the correct places.
249 static void split( std::list<ast::ptr<ast::Decl> > & translationUnit );
250
251 ast::Stmt * postvisit( const ast::ExprStmt * stmt );
252 void previsit( const ast::TupleAssignExpr * expr );
253 };
254 } // namespace
255
256 void fix( std::list< ast::ptr<ast::Decl> > & translationUnit, bool inLibrary ) {
257 ast::Pass<SelfAssignChecker> checker;
258 accept_all( translationUnit, checker );
259
260 // fixes StmtExpr to properly link to their resulting expression
261 StmtExprResult::link( translationUnit );
262
263 // fixes ConstructorInit for global variables. should happen before fixInitializers.
264 InitTweak::fixGlobalInit( translationUnit, inLibrary );
265
266 // must happen before ResolveCopyCtors because temporaries have to be inserted into the correct scope
267 SplitExpressions::split( translationUnit );
268
269 InsertImplicitCalls::insert( translationUnit );
270
271 // Needs to happen before ResolveCopyCtors, because argument/return temporaries should not be considered in
272 // error checking branch statements
273 InsertDtors::insert( translationUnit );
274
275 ResolveCopyCtors::resolveImplicitCalls( translationUnit );
276 FixInit::fixInitializers( translationUnit );
277 GenStructMemberCalls::generate( translationUnit );
278
279 // Needs to happen after GenStructMemberCalls, since otherwise member constructors exprs
280 // don't have the correct form, and a member can be constructed more than once.
281 FixCtorExprs::fix( translationUnit );
282 }
283
284 namespace {
285 /// find and return the destructor used in `input`. If `input` is not a simple destructor call, generate a thunk
286 /// that wraps the destructor, insert it into `stmtsToAdd` and return the new function declaration
287 const ast::DeclWithType * getDtorFunc( const ast::ObjectDecl * objDecl, const ast::Stmt * input, std::list< ast::ptr<ast::Stmt> > & stmtsToAdd ) {
288 const CodeLocation loc = input->location;
289 // unwrap implicit statement wrapper
290 // Statement * dtor = input;
291 assert( input );
292 // std::list< const ast::Expr * > matches;
293 auto matches = collectCtorDtorCalls( input );
294
295 if ( dynamic_cast< const ast::ExprStmt * >( input ) ) {
296 // only one destructor call in the expression
297 if ( matches.size() == 1 ) {
298 auto func = getFunction( matches.front() );
299 assertf( func, "getFunction failed to find function in %s", toString( matches.front() ).c_str() );
300
301 // cleanup argument must be a function, not an object (including function pointer)
302 if ( auto dtorFunc = dynamic_cast< const ast::FunctionDecl * > ( func ) ) {
303 if ( dtorFunc->type->forall.empty() ) {
304 // simple case where the destructor is a monomorphic function call - can simply
305 // use that function as the cleanup function.
306 return func;
307 }
308 }
309 }
310 }
311
312 // otherwise the cleanup is more complicated - need to build a single argument cleanup function that
313 // wraps the more complicated code.
314 static UniqueName dtorNamer( "__cleanup_dtor" );
315 std::string name = dtorNamer.newName();
316 ast::FunctionDecl * dtorFunc = SymTab::genDefaultFunc( loc, name, objDecl->type->stripReferences(), false );
317 stmtsToAdd.push_back( new ast::DeclStmt(loc, dtorFunc ) );
318
319 // the original code contains uses of objDecl - replace them with the newly generated 'this' parameter.
320 const ast::ObjectDecl * thisParam = getParamThis( dtorFunc );
321 const ast::Expr * replacement = new ast::VariableExpr( loc, thisParam );
322
323 auto base = replacement->result->stripReferences();
324 if ( dynamic_cast< const ast::ArrayType * >( base ) || dynamic_cast< const ast::TupleType * > ( base ) ) {
325 // need to cast away reference for array types, since the destructor is generated without the reference type,
326 // and for tuple types since tuple indexing does not work directly on a reference
327 replacement = new ast::CastExpr( replacement, base );
328 }
329 auto dtor = ast::DeclReplacer::replace( input, ast::DeclReplacer::ExprMap{ std::make_pair( objDecl, replacement ) } );
330 auto mutStmts = dtorFunc->stmts.get_and_mutate();
331 mutStmts->push_back(strict_dynamic_cast<const ast::Stmt *>( dtor ));
332 dtorFunc->stmts = mutStmts;
333
334 return dtorFunc;
335 }
336
337 void StmtExprResult::link( std::list<ast::ptr<ast::Decl> > & translationUnit ) {
338 ast::Pass<StmtExprResult> linker;
339 accept_all( translationUnit, linker );
340 }
341
342 void SplitExpressions::split( std::list<ast::ptr<ast::Decl> > & translationUnit ) {
343 ast::Pass<SplitExpressions> splitter;
344 accept_all( translationUnit, splitter );
345 }
346
347 void InsertImplicitCalls::insert( std::list<ast::ptr<ast::Decl> > & translationUnit ) {
348 ast::Pass<InsertImplicitCalls> inserter;
349 accept_all( translationUnit, inserter );
350 }
351
352 void ResolveCopyCtors::resolveImplicitCalls( std::list< ast::ptr<ast::Decl> > & translationUnit ) {
353 ast::Pass<ResolveCopyCtors> resolver;
354 accept_all( translationUnit, resolver );
355 }
356
357 void FixInit::fixInitializers( std::list< ast::ptr<ast::Decl> > & translationUnit ) {
358 ast::Pass<FixInit> fixer;
359
360 // can't use mutateAll, because need to insert declarations at top-level
361 // can't use DeclMutator, because sometimes need to insert IfStmt, etc.
362 SemanticErrorException errors;
363 for ( auto i = translationUnit.begin(); i != translationUnit.end(); ++i ) {
364 try {
365 // maybeAccept( *i, fixer ); translationUnit should never contain null
366 *i = (*i)->accept(fixer);
367 translationUnit.splice( i, fixer.core.staticDtorDecls );
368 } catch( SemanticErrorException &e ) {
369 errors.append( e );
370 } // try
371 } // for
372 if ( ! errors.isEmpty() ) {
373 throw errors;
374 } // if
375 }
376
377 void InsertDtors::insert( std::list< ast::ptr<ast::Decl> > & translationUnit ) {
378 ast::Pass<LabelFinder> finder;
379 ast::Pass<InsertDtors> inserter( finder );
380 accept_all( translationUnit, inserter );
381 }
382
383 void GenStructMemberCalls::generate( std::list< ast::ptr<ast::Decl> > & translationUnit ) {
384 ast::Pass<GenStructMemberCalls> warner;
385 accept_all( translationUnit, warner );
386 }
387
388 void FixCtorExprs::fix( std::list< ast::ptr<ast::Decl> > & translationUnit ) {
389 ast::Pass<FixCtorExprs> fixer;
390 accept_all( translationUnit, fixer );
391 }
392
393 const ast::StmtExpr * StmtExprResult::previsit( const ast::StmtExpr * stmtExpr ) {
394 // we might loose the result expression here so add a pointer to trace back
395 assert( stmtExpr->result );
396 const ast::Type * result = stmtExpr->result;
397 if ( ! result->isVoid() ) {
398 auto mutExpr = mutate(stmtExpr);
399 const ast::CompoundStmt * body = mutExpr->stmts;
400 assert( ! body->kids.empty() );
401 mutExpr->resultExpr = body->kids.back().strict_as<ast::ExprStmt>();
402 return mutExpr;
403 }
404 return stmtExpr;
405 }
406
407 ast::Stmt * SplitExpressions::postvisit( const ast::ExprStmt * stmt ) {
408 // wrap each top-level ExprStmt in a block so that destructors for argument and return temporaries are destroyed
409 // in the correct places
410 ast::CompoundStmt * ret = new ast::CompoundStmt( stmt->location, { stmt } );
411 return ret;
412 }
413
414 void SplitExpressions::previsit( const ast::TupleAssignExpr * ) {
415 // don't do this within TupleAssignExpr, since it is already broken up into multiple expressions
416 visit_children = false;
417 }
418
419 // Relatively simple structural comparison for expressions, needed to determine
420 // if two expressions are "the same" (used to determine if self assignment occurs)
421 struct StructuralChecker {
422 const ast::Expr * stripCasts( const ast::Expr * expr ) {
423 // this might be too permissive. It's possible that only particular casts are relevant.
424 while ( auto cast = dynamic_cast< const ast::CastExpr * >( expr ) ) {
425 expr = cast->arg;
426 }
427 return expr;
428 }
429
430 void previsit( const ast::Expr * ) {
431 // anything else does not qualify
432 isSimilar = false;
433 }
434
435 template<typename T>
436 T * cast( const ast::Expr * node ) {
437 // all expressions need to ignore casts, so this bit has been factored out
438 return dynamic_cast< T * >( stripCasts( node ) );
439 }
440
441 // ignore casts
442 void previsit( const ast::CastExpr * ) {}
443
444 void previsit( const ast::MemberExpr * memExpr ) {
445 if ( auto otherMember = cast< const ast::MemberExpr >( other ) ) {
446 if ( otherMember->member == memExpr->member ) {
447 other = otherMember->aggregate;
448 return;
449 }
450 }
451 isSimilar = false;
452 }
453
454 void previsit( const ast::VariableExpr * varExpr ) {
455 if ( auto otherVar = cast< const ast::VariableExpr >( other ) ) {
456 if ( otherVar->var == varExpr->var ) {
457 return;
458 }
459 }
460 isSimilar = false;
461 }
462
463 void previsit( const ast::AddressExpr * ) {
464 if ( auto addrExpr = cast< const ast::AddressExpr >( other ) ) {
465 other = addrExpr->arg;
466 return;
467 }
468 isSimilar = false;
469 }
470
471 const ast::Expr * other = nullptr;
472 bool isSimilar = true;
473 };
474
475 bool structurallySimilar( const ast::Expr * e1, const ast::Expr * e2 ) {
476 ast::Pass<StructuralChecker> checker;
477 checker.core.other = e2;
478 e1->accept( checker );
479 return checker.core.isSimilar;
480 }
481
482 void SelfAssignChecker::previsit( const ast::ApplicationExpr * appExpr ) {
483 auto function = getFunction( appExpr );
484 if ( function->name == "?=?" ) { // doesn't use isAssignment, because ?+=?, etc. should not count as self-assignment
485 if ( appExpr->args.size() == 2 ) {
486 // check for structural similarity (same variable use, ignore casts, etc. - but does not look too deeply, anything looking like a function is off limits)
487 if ( structurallySimilar( appExpr->args.front(), appExpr->args.back() ) ) {
488 SemanticWarning( appExpr->location, Warning::SelfAssignment, toCString( appExpr->args.front() ) );
489 }
490 }
491 }
492 }
493
494 const ast::Expr * InsertImplicitCalls::postvisit( const ast::ApplicationExpr * appExpr ) {
495 if ( auto function = appExpr->func.as<ast::VariableExpr>() ) {
496 if ( function->var->linkage.is_builtin ) {
497 // optimization: don't need to copy construct in order to call intrinsic functions
498 return appExpr;
499 } else if ( auto funcDecl = function->var.as<ast::DeclWithType>() ) {
500 auto ftype = dynamic_cast< const ast::FunctionType * >( GenPoly::getFunctionType( funcDecl->get_type() ) );
501 assertf( ftype, "Function call without function type: %s", toString( funcDecl ).c_str() );
502 if ( CodeGen::isConstructor( funcDecl->name ) && ftype->params.size() == 2 ) {
503 auto t1 = getPointerBase( ftype->params.front() );
504 auto t2 = ftype->params.back();
505 assert( t1 );
506
507 if ( ResolvExpr::typesCompatible( t1, t2 ) ) {
508 // optimization: don't need to copy construct in order to call a copy constructor
509 return appExpr;
510 } // if
511 } else if ( CodeGen::isDestructor( funcDecl->name ) ) {
512 // correctness: never copy construct arguments to a destructor
513 return appExpr;
514 } // if
515 } // if
516 } // if
517 CP_CTOR_PRINT( std::cerr << "InsertImplicitCalls: adding a wrapper " << appExpr << std::endl; )
518
519 // wrap each function call so that it is easy to identify nodes that have to be copy constructed
520 ast::ptr<ast::TypeSubstitution> tmp = appExpr->env;
521 auto mutExpr = mutate(appExpr);
522 mutExpr->env = nullptr;
523
524 auto expr = new ast::ImplicitCopyCtorExpr( appExpr->location, mutExpr );
525 // Move the type substitution to the new top-level, if it is attached to the appExpr.
526 // Ensure it is not deleted with the ImplicitCopyCtorExpr by removing it before deletion.
527 // The substitution is needed to obtain the type of temporary variables so that copy constructor
528 // calls can be resolved.
529 assert( typeSubs );
530 // assert (mutExpr->env);
531 expr->env = tmp;
532 // mutExpr->env = nullptr;
533 //std::swap( expr->env, appExpr->env );
534 return expr;
535 }
536
537 void ResolveCopyCtors::previsit(const ast::Expr * expr) {
538 if (expr->env) {
539 GuardValue(env);
540 GuardValue(envModified);
541 env = expr->env->clone();
542 envModified = false;
543 }
544 }
545
546 const ast::Expr * ResolveCopyCtors::postvisit(const ast::Expr * expr) {
547 if (expr->env) {
548 if (envModified) {
549 auto mutExpr = mutate(expr);
550 mutExpr->env = env;
551 return mutExpr;
552 }
553 else {
554 // env was not mutated, skip and delete the shallow copy
555 delete env;
556 return expr;
557 }
558 }
559 else {
560 return expr;
561 }
562 }
563
564 bool ResolveCopyCtors::skipCopyConstruct( const ast::Type * type ) { return ! isConstructable( type ); }
565
566 const ast::Expr * ResolveCopyCtors::makeCtorDtor( const std::string & fname, const ast::ObjectDecl * var, const ast::Expr * cpArg ) {
567 assert( var );
568 assert (var->isManaged());
569 assert (!cpArg || cpArg->isManaged());
570 // arrays are not copy constructed, so this should always be an ExprStmt
571 ast::ptr< ast::Stmt > stmt = genCtorDtor(var->location, fname, var, cpArg );
572 assertf( stmt, "ResolveCopyCtors: genCtorDtor returned nullptr: %s / %s / %s", fname.c_str(), toString( var ).c_str(), toString( cpArg ).c_str() );
573 auto exprStmt = stmt.strict_as<ast::ImplicitCtorDtorStmt>()->callStmt.strict_as<ast::ExprStmt>();
574 ast::ptr<ast::Expr> untyped = exprStmt->expr; // take ownership of expr
575 // exprStmt->expr = nullptr;
576
577 // resolve copy constructor
578 // should only be one alternative for copy ctor and dtor expressions, since all arguments are fixed
579 // (VariableExpr and already resolved expression)
580 CP_CTOR_PRINT( std::cerr << "ResolvingCtorDtor " << untyped << std::endl; )
581 ast::ptr<ast::Expr> resolved = ResolvExpr::findVoidExpression(untyped, symtab);
582 assert( resolved );
583 if ( resolved->env ) {
584 // Extract useful information and discard new environments. Keeping them causes problems in PolyMutator passes.
585 env->add( *resolved->env );
586 envModified = true;
587 // delete resolved->env;
588 auto mut = mutate(resolved.get());
589 assertf(mut == resolved.get(), "newly resolved expression must be unique");
590 mut->env = nullptr;
591 } // if
592 // delete stmt;
593 if ( auto assign = resolved.as<ast::TupleAssignExpr>() ) {
594 // fix newly generated StmtExpr
595 previsit( assign->stmtExpr );
596 }
597 return resolved.release();
598 }
599
600 ast::ptr<ast::Expr> ResolveCopyCtors::copyConstructArg(
601 const ast::Expr * arg, const ast::ImplicitCopyCtorExpr * impCpCtorExpr, const ast::Type * formal )
602 {
603 static UniqueName tempNamer("_tmp_cp");
604 assert( env );
605 const CodeLocation loc = impCpCtorExpr->location;
606 // CP_CTOR_PRINT( std::cerr << "Type Substitution: " << *env << std::endl; )
607 assert( arg->result );
608 ast::ptr<ast::Type> result = arg->result;
609 if ( skipCopyConstruct( result ) ) return arg; // skip certain non-copyable types
610
611 // type may involve type variables, so apply type substitution to get temporary variable's actual type,
612 // since result type may not be substituted (e.g., if the type does not appear in the parameter list)
613 // Use applyFree so that types bound in function pointers are not substituted, e.g. in forall(dtype T) void (*)(T).
614
615 // xxx - this originally mutates arg->result in place. is it correct?
616 result = env->applyFree( result.get() ).node;
617 auto mutResult = result.get_and_mutate();
618 mutResult->set_const(false);
619
620 auto mutArg = mutate(arg);
621 mutArg->result = mutResult;
622
623 ast::ptr<ast::Expr> guard = mutArg;
624
625 ast::ptr<ast::ObjectDecl> tmp = new ast::ObjectDecl({}, "__tmp", mutResult, nullptr );
626
627 // create and resolve copy constructor
628 CP_CTOR_PRINT( std::cerr << "makeCtorDtor for an argument" << std::endl; )
629 auto cpCtor = makeCtorDtor( "?{}", tmp, mutArg );
630
631 if ( auto appExpr = dynamic_cast< const ast::ApplicationExpr * >( cpCtor ) ) {
632 // if the chosen constructor is intrinsic, the copy is unnecessary, so
633 // don't create the temporary and don't call the copy constructor
634 auto function = appExpr->func.strict_as<ast::VariableExpr>();
635 if ( function->var->linkage == ast::Linkage::Intrinsic ) {
636 // arguments that need to be boxed need a temporary regardless of whether the copy constructor is intrinsic,
637 // so that the object isn't changed inside of the polymorphic function
638 if ( ! GenPoly::needsBoxing( formal, result, impCpCtorExpr->callExpr, env ) ) {
639 // xxx - should arg->result be mutated? see comment above.
640 return guard;
641 }
642 }
643 }
644
645 // set a unique name for the temporary once it's certain the call is necessary
646 auto mut = tmp.get_and_mutate();
647 assertf (mut == tmp, "newly created ObjectDecl must be unique");
648 mut->name = tempNamer.newName();
649
650 // replace argument to function call with temporary
651 stmtsToAddBefore.push_back( new ast::DeclStmt(loc, tmp ) );
652 arg = cpCtor;
653 return destructRet( tmp, arg );
654
655 // impCpCtorExpr->dtors.push_front( makeCtorDtor( "^?{}", tmp ) );
656 }
657
658 ast::Expr * ResolveCopyCtors::destructRet( const ast::ObjectDecl * ret, const ast::Expr * arg ) {
659 // TODO: refactor code for generating cleanup attribute, since it's common and reused in ~3-4 places
660 // check for existing cleanup attribute before adding another(?)
661 // need to add __Destructor for _tmp_cp variables as well
662
663 assertf( ast::dtorStruct && ast::dtorStruct->members.size() == 2, "Destructor generation requires __Destructor definition." );
664 assertf( ast::dtorStructDestroy, "Destructor generation requires __destroy_Destructor." );
665
666 const CodeLocation loc = ret->location;
667
668 // generate a __Destructor for ret that calls the destructor
669 auto res = makeCtorDtor( "^?{}", ret );
670 auto dtor = mutate(res);
671
672 // if the chosen destructor is intrinsic, elide the generated dtor handler
673 if ( arg && isIntrinsicCallExpr( dtor ) ) {
674 return new ast::CommaExpr(loc, arg, new ast::VariableExpr(loc, ret ) );
675 // return;
676 }
677
678 if ( ! dtor->env ) dtor->env = maybeClone( env );
679 auto dtorFunc = getDtorFunc( ret, new ast::ExprStmt(loc, dtor ), stmtsToAddBefore );
680
681 auto dtorStructType = new ast::StructInstType(ast::dtorStruct);
682
683 // what does this do???
684 dtorStructType->params.push_back( new ast::TypeExpr(loc, new ast::VoidType() ) );
685
686 // cast destructor pointer to void (*)(void *), to silence GCC incompatible pointer warnings
687 auto dtorFtype = new ast::FunctionType();
688 dtorFtype->params.push_back( new ast::PointerType(new ast::VoidType( ) ) );
689 auto dtorType = new ast::PointerType( dtorFtype );
690
691 static UniqueName namer( "_ret_dtor" );
692 auto retDtor = new ast::ObjectDecl(loc, namer.newName(), dtorStructType, new ast::ListInit(loc, { new ast::SingleInit(loc, ast::ConstantExpr::null(loc) ), new ast::SingleInit(loc, new ast::CastExpr( new ast::VariableExpr(loc, dtorFunc ), dtorType ) ) } ) );
693 retDtor->attributes.push_back( new ast::Attribute( "cleanup", { new ast::VariableExpr(loc, ast::dtorStructDestroy ) } ) );
694 stmtsToAddBefore.push_back( new ast::DeclStmt(loc, retDtor ) );
695
696 if ( arg ) {
697 auto member = new ast::MemberExpr(loc, ast::dtorStruct->members.front().strict_as<ast::DeclWithType>(), new ast::VariableExpr(loc, retDtor ) );
698 auto object = new ast::CastExpr( new ast::AddressExpr( new ast::VariableExpr(loc, ret ) ), new ast::PointerType(new ast::VoidType() ) );
699 ast::Expr * assign = createBitwiseAssignment( member, object );
700 return new ast::CommaExpr(loc, new ast::CommaExpr(loc, arg, assign ), new ast::VariableExpr(loc, ret ) );
701 }
702 return nullptr;
703 // impCpCtorExpr->get_dtors().push_front( makeCtorDtor( "^?{}", ret ) );
704 }
705
706 const ast::Expr * ResolveCopyCtors::postvisit( const ast::ImplicitCopyCtorExpr *impCpCtorExpr ) {
707 CP_CTOR_PRINT( std::cerr << "ResolveCopyCtors: " << impCpCtorExpr << std::endl; )
708
709 ast::ApplicationExpr * appExpr = mutate(impCpCtorExpr->callExpr.get());
710 const ast::ObjectDecl * returnDecl = nullptr;
711 const CodeLocation loc = appExpr->location;
712
713 // take each argument and attempt to copy construct it.
714 auto ftype = GenPoly::getFunctionType( appExpr->func->result );
715 assert( ftype );
716 auto & params = ftype->params;
717 auto iter = params.begin();
718 for ( auto & arg : appExpr->args ) {
719 const ast::Type * formal = nullptr;
720 if ( iter != params.end() ) { // does not copy construct C-style variadic arguments
721 // DeclarationWithType * param = *iter++;
722 formal = *iter++;
723 }
724
725 arg = copyConstructArg( arg, impCpCtorExpr, formal );
726 } // for
727
728 // each return value from the call needs to be connected with an ObjectDecl at the call site, which is
729 // initialized with the return value and is destructed later
730 // xxx - handle named return values?
731 const ast::Type * result = appExpr->result;
732 if ( ! result->isVoid() ) {
733 static UniqueName retNamer("_tmp_cp_ret");
734 // result = result->clone();
735 auto subResult = env->apply( result ).node;
736 auto ret = new ast::ObjectDecl(loc, retNamer.newName(), subResult, nullptr );
737 auto mutType = mutate(ret->type.get());
738 mutType->set_const( false );
739 ret->type = mutType;
740 returnDecl = ret;
741 stmtsToAddBefore.push_back( new ast::DeclStmt(loc, ret ) );
742 CP_CTOR_PRINT( std::cerr << "makeCtorDtor for a return" << std::endl; )
743 } // for
744 CP_CTOR_PRINT( std::cerr << "after Resolving: " << impCpCtorExpr << std::endl; )
745 // ------------------------------------------------------
746
747 CP_CTOR_PRINT( std::cerr << "Coming out the back..." << impCpCtorExpr << std::endl; )
748
749 // detach fields from wrapper node so that it can be deleted without deleting too much
750
751 // xxx - actual env might be somewhere else, need to keep invariant
752
753 // deletion of wrapper should be handled by pass template now
754
755 // impCpCtorExpr->callExpr = nullptr;
756 assert (appExpr->env == nullptr);
757 appExpr->env = impCpCtorExpr->env;
758 // std::swap( impCpCtorExpr->env, appExpr->env );
759 // assert( impCpCtorExpr->env == nullptr );
760 // delete impCpCtorExpr;
761
762 if ( returnDecl ) {
763 ast::Expr * assign = createBitwiseAssignment( new ast::VariableExpr(loc, returnDecl ), appExpr );
764 if ( ! dynamic_cast< const ast::ReferenceType * >( result ) ) {
765 // destructing reference returns is bad because it can cause multiple destructor calls to the same object - the returned object is not a temporary
766 assign = destructRet( returnDecl, assign );
767 assert(assign);
768 } else {
769 assign = new ast::CommaExpr(loc, assign, new ast::VariableExpr(loc, returnDecl ) );
770 }
771 // move env from appExpr to retExpr
772 // std::swap( assign->env, appExpr->env );
773 assign->env = appExpr->env;
774 // actual env is handled by common routine that replaces WithTypeSubstitution
775 return postvisit((const ast::Expr *)assign);
776 } else {
777 return postvisit((const ast::Expr *)appExpr);
778 } // if
779 }
780
781 const ast::StmtExpr * ResolveCopyCtors::previsit( const ast::StmtExpr * _stmtExpr ) {
782 // function call temporaries should be placed at statement-level, rather than nested inside of a new statement expression,
783 // since temporaries can be shared across sub-expressions, e.g.
784 // [A, A] f(); // decl
785 // g([A] x, [A] y); // decl
786 // g(f()); // call
787 // f is executed once, so the return temporary is shared across the tuple constructors for x and y.
788 // Explicitly mutating children instead of mutating the inner compound statement forces the temporaries to be added
789 // to the outer context, rather than inside of the statement expression.
790
791 // call the common routine that replaces WithTypeSubstitution
792 previsit((const ast::Expr *) _stmtExpr);
793
794 visit_children = false;
795 const CodeLocation loc = _stmtExpr->location;
796
797 assert( env );
798
799 symtab.enterScope();
800 // visit all statements
801 auto stmtExpr = mutate(_stmtExpr);
802 auto mutStmts = mutate(stmtExpr->stmts.get());
803
804 auto & stmts = mutStmts->kids;
805 for ( auto & stmt : stmts ) {
806 stmt = stmt->accept( *visitor );
807 } // for
808 stmtExpr->stmts = mutStmts;
809 symtab.leaveScope();
810
811 assert( stmtExpr->result );
812 // const ast::Type * result = stmtExpr->result;
813 if ( ! stmtExpr->result->isVoid() ) {
814 static UniqueName retNamer("_tmp_stmtexpr_ret");
815
816 // result = result->clone();
817 auto result = env->apply( stmtExpr->result.get() ).node;
818 if ( ! InitTweak::isConstructable( result ) ) {
819 // delete result;
820 return stmtExpr;
821 }
822 auto mutResult = result.get_and_mutate();
823 mutResult->set_const(false);
824
825 // create variable that will hold the result of the stmt expr
826 auto ret = new ast::ObjectDecl(loc, retNamer.newName(), mutResult, nullptr );
827 stmtsToAddBefore.push_back( new ast::DeclStmt(loc, ret ) );
828
829 assertf(
830 stmtExpr->resultExpr,
831 "Statement-Expression should have a resulting expression at %s:%d",
832 stmtExpr->location.filename.c_str(),
833 stmtExpr->location.first_line
834 );
835
836 const ast::ExprStmt * last = stmtExpr->resultExpr;
837 // xxx - if this is non-unique, need to copy while making resultExpr ref
838 assertf(last->unique(), "attempt to modify weakly shared statement");
839 auto mutLast = mutate(last);
840 // above assertion means in-place mutation is OK
841 try {
842 mutLast->expr = makeCtorDtor( "?{}", ret, mutLast->expr );
843 } catch(...) {
844 std::cerr << "*CFA internal error: ";
845 std::cerr << "can't resolve implicit constructor";
846 std::cerr << " at " << stmtExpr->location.filename;
847 std::cerr << ":" << stmtExpr->location.first_line << std::endl;
848
849 abort();
850 }
851
852 // add destructors after current statement
853 stmtsToAddAfter.push_back( new ast::ExprStmt(loc, makeCtorDtor( "^?{}", ret ) ) );
854
855 // must have a non-empty body, otherwise it wouldn't have a result
856 assert( ! stmts.empty() );
857
858 // if there is a return decl, add a use as the last statement; will not have return decl on non-constructable returns
859 stmts.push_back( new ast::ExprStmt(loc, new ast::VariableExpr(loc, ret ) ) );
860 } // if
861
862 assert( stmtExpr->returnDecls.empty() );
863 assert( stmtExpr->dtors.empty() );
864
865 return stmtExpr;
866 }
867
868 // to prevent warnings ('_unq0' may be used uninitialized in this function),
869 // insert an appropriate zero initializer for UniqueExpr temporaries.
870 ast::Init * makeInit( const ast::Type * t ) {
871 if ( auto inst = dynamic_cast< const ast::StructInstType * >( t ) ) {
872 // initizer for empty struct must be empty
873 if ( inst->base->members.empty() ) return new ast::ListInit({}, {});
874 } else if ( auto inst = dynamic_cast< const ast::UnionInstType * >( t ) ) {
875 // initizer for empty union must be empty
876 if ( inst->base->members.empty() ) return new ast::ListInit({}, {});
877 }
878
879 return new ast::ListInit( {}, { new ast::SingleInit( {}, ast::ConstantExpr::from_int({}, 0) ) } );
880 }
881
882 const ast::UniqueExpr * ResolveCopyCtors::previsit( const ast::UniqueExpr * unqExpr ) {
883 visit_children = false;
884 // xxx - hack to prevent double-handling of unique exprs, otherwise too many temporary variables and destructors are generated
885 static std::unordered_map< int, const ast::UniqueExpr * > unqMap;
886 auto mutExpr = mutate(unqExpr);
887 if ( ! unqMap.count( unqExpr->id ) ) {
888 // resolve expr and find its
889
890 auto impCpCtorExpr = mutExpr->expr.as<ast::ImplicitCopyCtorExpr>();
891 // PassVisitor<ResolveCopyCtors> fixer;
892
893 mutExpr->expr = mutExpr->expr->accept( *visitor );
894 // it should never be necessary to wrap a void-returning expression in a UniqueExpr - if this assumption changes, this needs to be rethought
895 assert( unqExpr->result );
896 if ( impCpCtorExpr ) {
897 auto comma = unqExpr->expr.strict_as<ast::CommaExpr>();
898 auto var = comma->arg2.strict_as<ast::VariableExpr>();
899 // note the variable used as the result from the call
900 mutExpr->var = var;
901 } else {
902 // expr isn't a call expr, so create a new temporary variable to use to hold the value of the unique expression
903 mutExpr->object = new ast::ObjectDecl( mutExpr->location, toString("_unq", mutExpr->id), mutExpr->result, makeInit( mutExpr->result ) );
904 mutExpr->var = new ast::VariableExpr( mutExpr->location, mutExpr->object );
905 }
906
907 // stmtsToAddBefore.splice( stmtsToAddBefore.end(), fixer.pass.stmtsToAddBefore );
908 // stmtsToAddAfter.splice( stmtsToAddAfter.end(), fixer.pass.stmtsToAddAfter );
909 unqMap[mutExpr->id] = mutExpr;
910 } else {
911 // take data from other UniqueExpr to ensure consistency
912 // delete unqExpr->get_expr();
913 mutExpr->expr = unqMap[mutExpr->id]->expr;
914 // delete unqExpr->result;
915 mutExpr->result = mutExpr->expr->result;
916 }
917 return mutExpr;
918 }
919
920 const ast::DeclWithType * FixInit::postvisit( const ast::ObjectDecl *_objDecl ) {
921 const CodeLocation loc = _objDecl->location;
922
923 // since this removes the init field from objDecl, it must occur after children are mutated (i.e. postvisit)
924 if ( ast::ptr<ast::ConstructorInit> ctorInit = _objDecl->init.as<ast::ConstructorInit>() ) {
925 auto objDecl = mutate(_objDecl);
926
927 // could this be non-unique?
928 if (objDecl != _objDecl) {
929 std::cerr << "FixInit: non-unique object decl " << objDecl->location << objDecl->name << std::endl;
930 }
931 // a decision should have been made by the resolver, so ctor and init are not both non-NULL
932 assert( ! ctorInit->ctor || ! ctorInit->init );
933 if ( const ast::Stmt * ctor = ctorInit->ctor ) {
934 if ( objDecl->storage.is_static ) {
935 // originally wanted to take advantage of gcc nested functions, but
936 // we get memory errors with this approach. To remedy this, the static
937 // variable is hoisted when the destructor needs to be called.
938 //
939 // generate:
940 // static T __objName_static_varN;
941 // void __objName_dtor_atexitN() {
942 // __dtor__...;
943 // }
944 // int f(...) {
945 // ...
946 // static bool __objName_uninitialized = true;
947 // if (__objName_uninitialized) {
948 // __ctor(__objName);
949 // __objName_uninitialized = false;
950 // atexit(__objName_dtor_atexitN);
951 // }
952 // ...
953 // }
954
955 static UniqueName dtorCallerNamer( "_dtor_atexit" );
956
957 // static bool __objName_uninitialized = true
958 auto boolType = new ast::BasicType( ast::BasicType::Kind::Bool );
959 auto boolInitExpr = new ast::SingleInit(loc, ast::ConstantExpr::from_int(loc, 1 ) );
960 auto isUninitializedVar = new ast::ObjectDecl(loc, objDecl->mangleName + "_uninitialized", boolType, boolInitExpr, ast::Storage::Static, ast::Linkage::Cforall);
961 isUninitializedVar->fixUniqueId();
962
963 // __objName_uninitialized = false;
964 auto setTrue = new ast::UntypedExpr(loc, new ast::NameExpr(loc, "?=?" ) );
965 setTrue->args.push_back( new ast::VariableExpr(loc, isUninitializedVar ) );
966 setTrue->args.push_back( ast::ConstantExpr::from_int(loc, 0 ) );
967
968 // generate body of if
969 auto initStmts = new ast::CompoundStmt(loc);
970 auto & body = initStmts->kids;
971 body.push_back( ctor );
972 body.push_back( new ast::ExprStmt(loc, setTrue ) );
973
974 // put it all together
975 auto ifStmt = new ast::IfStmt(loc, new ast::VariableExpr(loc, isUninitializedVar ), initStmts, 0 );
976 stmtsToAddAfter.push_back( new ast::DeclStmt(loc, isUninitializedVar ) );
977 stmtsToAddAfter.push_back( ifStmt );
978
979 const ast::Stmt * dtor = ctorInit->dtor;
980
981 // these should be automatically managed once reassigned
982 // objDecl->set_init( nullptr );
983 // ctorInit->set_ctor( nullptr );
984 // ctorInit->set_dtor( nullptr );
985 if ( dtor ) {
986 // if the object has a non-trivial destructor, have to
987 // hoist it and the object into the global space and
988 // call the destructor function with atexit.
989
990 // Statement * dtorStmt = dtor->clone();
991
992 // void __objName_dtor_atexitN(...) {...}
993 ast::FunctionDecl * dtorCaller = new ast::FunctionDecl(loc, objDecl->mangleName + dtorCallerNamer.newName(), {}, {}, {}, new ast::CompoundStmt(loc, {dtor}), ast::Storage::Static, ast::Linkage::C );
994 dtorCaller->fixUniqueId();
995 // dtorCaller->stmts->push_back( dtor );
996
997 // atexit(dtor_atexit);
998 auto callAtexit = new ast::UntypedExpr(loc, new ast::NameExpr(loc, "atexit" ) );
999 callAtexit->args.push_back( new ast::VariableExpr(loc, dtorCaller ) );
1000
1001 body.push_back( new ast::ExprStmt(loc, callAtexit ) );
1002
1003 // hoist variable and dtor caller decls to list of decls that will be added into global scope
1004 staticDtorDecls.push_back( objDecl );
1005 staticDtorDecls.push_back( dtorCaller );
1006
1007 // need to rename object uniquely since it now appears
1008 // at global scope and there could be multiple function-scoped
1009 // static variables with the same name in different functions.
1010 // Note: it isn't sufficient to modify only the mangleName, because
1011 // then subsequent Indexer passes can choke on seeing the object's name
1012 // if another object has the same name and type. An unfortunate side-effect
1013 // of renaming the object is that subsequent NameExprs may fail to resolve,
1014 // but there shouldn't be any remaining past this point.
1015 static UniqueName staticNamer( "_static_var" );
1016 objDecl->name = objDecl->name + staticNamer.newName();
1017 objDecl->mangleName = Mangle::mangle( objDecl );
1018
1019 // xxx - temporary hack: need to return a declaration, but want to hoist the current object out of this scope
1020 // create a new object which is never used
1021 static UniqueName dummyNamer( "_dummy" );
1022 auto dummy = new ast::ObjectDecl(loc, dummyNamer.newName(), new ast::PointerType(new ast::VoidType()), nullptr, ast::Storage::Static, ast::Linkage::Cforall, 0, { new ast::Attribute("unused") } );
1023 // delete ctorInit;
1024 return dummy;
1025 } else {
1026 objDecl->init = nullptr;
1027 return objDecl;
1028 }
1029 } else {
1030 auto implicit = strict_dynamic_cast< const ast::ImplicitCtorDtorStmt * > ( ctor );
1031 auto ctorStmt = implicit->callStmt.as<ast::ExprStmt>();
1032 const ast::ApplicationExpr * ctorCall = nullptr;
1033 if ( ctorStmt && (ctorCall = isIntrinsicCallExpr( ctorStmt->expr )) && ctorCall->args.size() == 2 ) {
1034 // clean up intrinsic copy constructor calls by making them into SingleInits
1035 const ast::Expr * ctorArg = ctorCall->args.back();
1036 // ctorCall should be gone afterwards
1037 auto mutArg = mutate(ctorArg);
1038 mutArg->env = ctorCall->env;
1039 // std::swap( ctorArg->env, ctorCall->env );
1040 objDecl->init = new ast::SingleInit(loc, mutArg );
1041
1042 // ctorCall->args.pop_back();
1043 } else {
1044 stmtsToAddAfter.push_back( ctor );
1045 objDecl->init = nullptr;
1046 // ctorInit->ctor = nullptr;
1047 }
1048
1049 const ast::Stmt * dtor = ctorInit->dtor;
1050 if ( dtor ) {
1051 auto implicit = strict_dynamic_cast< const ast::ImplicitCtorDtorStmt * >( dtor );
1052 const ast::Stmt * dtorStmt = implicit->callStmt;
1053
1054 // don't need to call intrinsic dtor, because it does nothing, but
1055 // non-intrinsic dtors must be called
1056 if ( ! isIntrinsicSingleArgCallStmt( dtorStmt ) ) {
1057 // set dtor location to the object's location for error messages
1058 auto dtorFunc = getDtorFunc( objDecl, dtorStmt, stmtsToAddBefore );
1059 objDecl->attributes.push_back( new ast::Attribute( "cleanup", { new ast::VariableExpr(loc, dtorFunc ) } ) );
1060 // ctorInit->dtor = nullptr;
1061 } // if
1062 }
1063 } // if
1064 } else if ( const ast::Init * init = ctorInit->init ) {
1065 objDecl->init = init;
1066 // ctorInit->init = nullptr;
1067 } else {
1068 // no constructor and no initializer, which is okay
1069 objDecl->init = nullptr;
1070 } // if
1071 // delete ctorInit;
1072 return objDecl;
1073 } // if
1074 return _objDecl;
1075 }
1076
1077 void ObjDeclCollector::previsit( const ast::CompoundStmt * ) {
1078 GuardValue( curVars );
1079 }
1080
1081 void ObjDeclCollector::previsit( const ast::DeclStmt * stmt ) {
1082 // keep track of all variables currently in scope
1083 if ( auto objDecl = stmt->decl.as<ast::ObjectDecl>() ) {
1084 curVars.push_back( objDecl );
1085 } // if
1086 }
1087
1088 void LabelFinder::previsit( const ast::Stmt * stmt ) {
1089 // for each label, remember the variables in scope at that label.
1090 for ( auto l : stmt->labels ) {
1091 vars[l] = curVars;
1092 } // for
1093 }
1094
1095 void LabelFinder::previsit( const ast::CompoundStmt * stmt ) {
1096 previsit( (const ast::Stmt *) stmt );
1097 Parent::previsit( stmt );
1098 }
1099
1100 void LabelFinder::previsit( const ast::DeclStmt * stmt ) {
1101 previsit( (const ast::Stmt *)stmt );
1102 Parent::previsit( stmt );
1103 }
1104
1105
1106 void InsertDtors::previsit( const ast::FunctionDecl * funcDecl ) {
1107 // each function needs to have its own set of labels
1108 GuardValue( labelVars );
1109 labelVars.clear();
1110 // LabelFinder does not recurse into FunctionDecl, so need to visit
1111 // its children manually.
1112 if (funcDecl->type) funcDecl->type->accept(finder);
1113 // maybeAccept( funcDecl->type, finder );
1114 if (funcDecl->stmts) funcDecl->stmts->accept(finder) ;
1115
1116 // all labels for this function have been collected, insert destructors as appropriate via implicit recursion.
1117 }
1118
1119 // Handle break/continue/goto in the same manner as C++. Basic idea: any objects that are in scope at the
1120 // BranchStmt but not at the labelled (target) statement must be destructed. If there are any objects in scope
1121 // at the target location but not at the BranchStmt then those objects would be uninitialized so notify the user
1122 // of the error. See C++ Reference 6.6 Jump Statements for details.
1123 void InsertDtors::handleGoto( const ast::BranchStmt * stmt ) {
1124 // can't do anything for computed goto
1125 if ( stmt->computedTarget ) return;
1126
1127 assertf( stmt->target.name != "", "BranchStmt missing a label: %s", toString( stmt ).c_str() );
1128 // S_L = lvars = set of objects in scope at label definition
1129 // S_G = curVars = set of objects in scope at goto statement
1130 ObjectSet & lvars = labelVars[ stmt->target ];
1131
1132 DTOR_PRINT(
1133 std::cerr << "at goto label: " << stmt->target.name << std::endl;
1134 std::cerr << "S_G = " << printSet( curVars ) << std::endl;
1135 std::cerr << "S_L = " << printSet( lvars ) << std::endl;
1136 )
1137
1138
1139 // std::set_difference requires that the inputs be sorted.
1140 lvars.sort();
1141 curVars.sort();
1142
1143 ObjectSet diff;
1144 // S_L-S_G results in set of objects whose construction is skipped - it's an error if this set is non-empty
1145 std::set_difference( lvars.begin(), lvars.end(), curVars.begin(), curVars.end(), std::inserter( diff, diff.begin() ) );
1146 DTOR_PRINT(
1147 std::cerr << "S_L-S_G = " << printSet( diff ) << std::endl;
1148 )
1149 if ( ! diff.empty() ) {
1150 SemanticError( stmt, std::string("jump to label '") + stmt->target.name + "' crosses initialization of " + (*diff.begin())->name + " " );
1151 } // if
1152 }
1153
1154 void InsertDtors::previsit( const ast::BranchStmt * stmt ) {
1155 switch( stmt->kind ) {
1156 case ast::BranchStmt::Continue:
1157 case ast::BranchStmt::Break:
1158 // could optimize the break/continue case, because the S_L-S_G check is unnecessary (this set should
1159 // always be empty), but it serves as a small sanity check.
1160 case ast::BranchStmt::Goto:
1161 handleGoto( stmt );
1162 break;
1163 default:
1164 assert( false );
1165 } // switch
1166 }
1167
1168 bool checkWarnings( const ast::FunctionDecl * funcDecl ) {
1169 // only check for warnings if the current function is a user-defined
1170 // constructor or destructor
1171 if ( ! funcDecl ) return false;
1172 if ( ! funcDecl->stmts ) return false;
1173 return CodeGen::isCtorDtor( funcDecl->name ) && ! funcDecl->linkage.is_overrideable;
1174 }
1175
1176 void GenStructMemberCalls::previsit( const ast::FunctionDecl * funcDecl ) {
1177 GuardValue( function );
1178 GuardValue( unhandled );
1179 GuardValue( usedUninit );
1180 GuardValue( thisParam );
1181 GuardValue( isCtor );
1182 GuardValue( structDecl );
1183 errors = SemanticErrorException(); // clear previous errors
1184
1185 // need to start with fresh sets
1186 unhandled.clear();
1187 usedUninit.clear();
1188
1189 function = mutate(funcDecl);
1190 // could this be non-unique?
1191 if (function != funcDecl) {
1192 std::cerr << "GenStructMemberCalls: non-unique FunctionDecl " << funcDecl->location << funcDecl->name << std::endl;
1193 }
1194
1195 isCtor = CodeGen::isConstructor( function->name );
1196 if ( checkWarnings( function ) ) {
1197 // const ast::FunctionType * type = function->type;
1198 // assert( ! type->params.empty() );
1199 thisParam = function->params.front().strict_as<ast::ObjectDecl>();
1200 auto thisType = getPointerBase( thisParam->get_type() );
1201 auto structType = dynamic_cast< const ast::StructInstType * >( thisType );
1202 if ( structType ) {
1203 structDecl = structType->base;
1204 for ( auto & member : structDecl->members ) {
1205 if ( auto field = member.as<ast::ObjectDecl>() ) {
1206 // record all of the struct type's members that need to be constructed or
1207 // destructed by the end of the function
1208 unhandled.insert( field );
1209 }
1210 }
1211 }
1212 }
1213 }
1214
1215 const ast::DeclWithType * GenStructMemberCalls::postvisit( const ast::FunctionDecl * funcDecl ) {
1216 // remove the unhandled objects from usedUninit, because a call is inserted
1217 // to handle them - only objects that are later constructed are used uninitialized.
1218 std::map< const ast::DeclWithType *, CodeLocation > diff;
1219 // need the comparator since usedUninit and unhandled have different types
1220 struct comp_t {
1221 typedef decltype(usedUninit)::value_type usedUninit_t;
1222 typedef decltype(unhandled)::value_type unhandled_t;
1223 bool operator()(usedUninit_t x, unhandled_t y) { return x.first < y; }
1224 bool operator()(unhandled_t x, usedUninit_t y) { return x < y.first; }
1225 } comp;
1226 std::set_difference( usedUninit.begin(), usedUninit.end(), unhandled.begin(), unhandled.end(), std::inserter( diff, diff.begin() ), comp );
1227 for ( auto p : diff ) {
1228 auto member = p.first;
1229 auto loc = p.second;
1230 // xxx - make error message better by also tracking the location that the object is constructed at?
1231 emit( loc, "in ", function->name, ", field ", member->name, " used before being constructed" );
1232 }
1233
1234 const CodeLocation loc = funcDecl->location;
1235
1236 if ( ! unhandled.empty() ) {
1237 auto mutStmts = function->stmts.get_and_mutate();
1238 // need to explicitly re-add function parameters to the indexer in order to resolve copy constructors
1239 auto guard = makeFuncGuard( [this]() { symtab.enterScope(); }, [this]() { symtab.leaveScope(); } );
1240 symtab.addFunction( function );
1241
1242 // need to iterate through members in reverse in order for
1243 // ctor/dtor statements to come out in the right order
1244 for ( auto & member : reverseIterate( structDecl->members ) ) {
1245 auto field = member.as<ast::ObjectDecl>();
1246 // skip non-DWT members
1247 if ( ! field ) continue;
1248 // skip non-constructable members
1249 if ( ! tryConstruct( field ) ) continue;
1250 // skip handled members
1251 if ( ! unhandled.count( field ) ) continue;
1252
1253 // insert and resolve default/copy constructor call for each field that's unhandled
1254 // std::list< const ast::Stmt * > stmt;
1255 ast::Expr * arg2 = nullptr;
1256 if ( function->name == "?{}" && isCopyFunction( function ) ) {
1257 // if copy ctor, need to pass second-param-of-this-function.field
1258 // std::list< DeclarationWithType * > & params = function->get_functionType()->get_parameters();
1259 assert( function->params.size() == 2 );
1260 arg2 = new ast::MemberExpr(funcDecl->location, field, new ast::VariableExpr(funcDecl->location, function->params.back() ) );
1261 }
1262 InitExpander_new srcParam( arg2 );
1263 // cast away reference type and construct field.
1264 ast::Expr * thisExpr = new ast::CastExpr(funcDecl->location, new ast::VariableExpr(funcDecl->location, thisParam ), thisParam->get_type()->stripReferences());
1265 ast::Expr * memberDest = new ast::MemberExpr(funcDecl->location, field, thisExpr );
1266 ast::ptr<ast::Stmt> callStmt = SymTab::genImplicitCall( srcParam, memberDest, loc, function->name, field, static_cast<SymTab::LoopDirection>(isCtor) );
1267
1268 if ( callStmt ) {
1269 // auto & callStmt = stmt.front();
1270
1271 try {
1272 callStmt = callStmt->accept( *visitor );
1273 if ( isCtor ) {
1274 mutStmts->push_front( callStmt );
1275 } else { // TODO: don't generate destructor function/object for intrinsic calls
1276 // destructor statements should be added at the end
1277 // function->get_statements()->push_back( callStmt );
1278
1279 // Optimization: do not need to call intrinsic destructors on members
1280 if ( isIntrinsicSingleArgCallStmt( callStmt ) ) continue;
1281
1282 // __Destructor _dtor0 = { (void *)&b.a1, (void (*)(void *)_destroy_A };
1283 std::list< ast::ptr<ast::Stmt> > stmtsToAdd;
1284
1285 static UniqueName memberDtorNamer = { "__memberDtor" };
1286 assertf( Validate::dtorStruct, "builtin __Destructor not found." );
1287 assertf( Validate::dtorStructDestroy, "builtin __destroy_Destructor not found." );
1288
1289 ast::Expr * thisExpr = new ast::CastExpr( new ast::AddressExpr( new ast::VariableExpr(loc, thisParam ) ), new ast::PointerType( new ast::VoidType(), ast::CV::Qualifiers() ) );
1290 ast::Expr * dtorExpr = new ast::VariableExpr(loc, getDtorFunc( thisParam, callStmt, stmtsToAdd ) );
1291
1292 // cast destructor pointer to void (*)(void *), to silence GCC incompatible pointer warnings
1293 auto dtorFtype = new ast::FunctionType();
1294 dtorFtype->params.emplace_back( new ast::PointerType( new ast::VoidType() ) );
1295 auto dtorType = new ast::PointerType( dtorFtype );
1296
1297 auto destructor = new ast::ObjectDecl(loc, memberDtorNamer.newName(), new ast::StructInstType( ast::dtorStruct ), new ast::ListInit(loc, { new ast::SingleInit(loc, thisExpr ), new ast::SingleInit(loc, new ast::CastExpr( dtorExpr, dtorType ) ) } ) );
1298 destructor->attributes.push_back( new ast::Attribute( "cleanup", { new ast::VariableExpr({}, ast::dtorStructDestroy ) } ) );
1299 mutStmts->push_front( new ast::DeclStmt(loc, destructor ) );
1300 mutStmts->kids.splice( mutStmts->kids.begin(), stmtsToAdd );
1301 }
1302 } catch ( SemanticErrorException & error ) {
1303 emit( funcDecl->location, "in ", function->name , ", field ", field->name, " not explicitly ", isCtor ? "constructed" : "destructed", " and no ", isCtor ? "default constructor" : "destructor", " found" );
1304 }
1305 }
1306 }
1307 function->stmts = mutStmts;
1308 }
1309 if (! errors.isEmpty()) {
1310 throw errors;
1311 }
1312 // return funcDecl;
1313 return function;
1314 }
1315
1316 /// true if expr is effectively just the 'this' parameter
1317 bool isThisExpression( const ast::Expr * expr, const ast::DeclWithType * thisParam ) {
1318 // TODO: there are more complicated ways to pass 'this' to a constructor, e.g. &*, *&, etc.
1319 if ( auto varExpr = dynamic_cast< const ast::VariableExpr * >( expr ) ) {
1320 return varExpr->var == thisParam;
1321 } else if ( auto castExpr = dynamic_cast< const ast::CastExpr * > ( expr ) ) {
1322 return isThisExpression( castExpr->arg, thisParam );
1323 }
1324 return false;
1325 }
1326
1327 /// returns a MemberExpr if expr is effectively just member access on the 'this' parameter, else nullptr
1328 const ast::MemberExpr * isThisMemberExpr( const ast::Expr * expr, const ast::DeclWithType * thisParam ) {
1329 if ( auto memberExpr = dynamic_cast< const ast::MemberExpr * >( expr ) ) {
1330 if ( isThisExpression( memberExpr->aggregate, thisParam ) ) {
1331 return memberExpr;
1332 }
1333 } else if ( auto castExpr = dynamic_cast< const ast::CastExpr * >( expr ) ) {
1334 return isThisMemberExpr( castExpr->arg, thisParam );
1335 }
1336 return nullptr;
1337 }
1338
1339 void GenStructMemberCalls::previsit( const ast::ApplicationExpr * appExpr ) {
1340 if ( ! checkWarnings( function ) ) {
1341 visit_children = false;
1342 return;
1343 }
1344
1345 std::string fname = getFunctionName( appExpr );
1346 if ( fname == function->name ) {
1347 // call to same kind of function
1348 const ast::Expr * firstParam = appExpr->args.front();
1349
1350 if ( isThisExpression( firstParam, thisParam ) ) {
1351 // if calling another constructor on thisParam, assume that function handles
1352 // all members - if it doesn't a warning will appear in that function.
1353 unhandled.clear();
1354 } else if ( auto memberExpr = isThisMemberExpr( firstParam, thisParam ) ) {
1355 // if first parameter is a member expression on the this parameter,
1356 // then remove the member from unhandled set.
1357 if ( isThisExpression( memberExpr->aggregate, thisParam ) ) {
1358 unhandled.erase( memberExpr->member );
1359 }
1360 }
1361 }
1362 }
1363
1364 void GenStructMemberCalls::previsit( const ast::MemberExpr * memberExpr ) {
1365 if ( ! checkWarnings( function ) || ! isCtor ) {
1366 visit_children = false;
1367 return;
1368 }
1369
1370 if ( isThisExpression( memberExpr->aggregate, thisParam ) ) {
1371 if ( unhandled.count( memberExpr->member ) ) {
1372 // emit a warning because a member was used before it was constructed
1373 usedUninit.insert( { memberExpr->member, memberExpr->location } );
1374 }
1375 }
1376 }
1377
1378 template< typename Visitor, typename... Params >
1379 void error( Visitor & v, CodeLocation loc, const Params &... params ) {
1380 SemanticErrorException err( loc, toString( params... ) );
1381 v.errors.append( err );
1382 }
1383
1384 template< typename... Params >
1385 void GenStructMemberCalls::emit( CodeLocation loc, const Params &... params ) {
1386 // toggle warnings vs. errors here.
1387 // warn( params... );
1388 error( *this, loc, params... );
1389 }
1390
1391 const ast::Expr * GenStructMemberCalls::postvisit( const ast::UntypedExpr * untypedExpr ) {
1392 // Expression * newExpr = untypedExpr;
1393 // xxx - functions returning ast::ptr seems wrong...
1394 auto res = ResolvExpr::findVoidExpression( untypedExpr, symtab );
1395 return res.release();
1396 // return newExpr;
1397 }
1398
1399 void InsertImplicitCalls::previsit(const ast::UniqueExpr * unqExpr) {
1400 if (visitedIds.count(unqExpr->id)) visit_children = false;
1401 else visitedIds.insert(unqExpr->id);
1402 }
1403
1404 const ast::Expr * FixCtorExprs::postvisit( const ast::ConstructorExpr * ctorExpr ) {
1405 const CodeLocation loc = ctorExpr->location;
1406 static UniqueName tempNamer( "_tmp_ctor_expr" );
1407 // xxx - is the size check necessary?
1408 assert( ctorExpr->result && ctorExpr->result->size() == 1 );
1409
1410 // xxx - this can be TupleAssignExpr now. Need to properly handle this case.
1411 // take possession of expr and env
1412 ast::ptr<ast::ApplicationExpr> callExpr = ctorExpr->callExpr.strict_as<ast::ApplicationExpr>();
1413 ast::ptr<ast::TypeSubstitution> env = ctorExpr->env;
1414 // ctorExpr->set_callExpr( nullptr );
1415 // ctorExpr->set_env( nullptr );
1416
1417 // xxx - ideally we would reuse the temporary generated from the copy constructor passes from within firstArg if it exists and not generate a temporary if it's unnecessary.
1418 auto tmp = new ast::ObjectDecl(loc, tempNamer.newName(), callExpr->args.front()->result );
1419 declsToAddBefore.push_back( tmp );
1420 // delete ctorExpr;
1421
1422 // build assignment and replace constructor's first argument with new temporary
1423 auto mutCallExpr = callExpr.get_and_mutate();
1424 const ast::Expr * firstArg = callExpr->args.front();
1425 ast::Expr * assign = new ast::UntypedExpr(loc, new ast::NameExpr(loc, "?=?" ), { new ast::AddressExpr(loc, new ast::VariableExpr(loc, tmp ) ), new ast::AddressExpr( firstArg ) } );
1426 firstArg = new ast::VariableExpr(loc, tmp );
1427 mutCallExpr->args.front() = firstArg;
1428
1429 // resolve assignment and dispose of new env
1430 auto resolved = ResolvExpr::findVoidExpression( assign, symtab );
1431 auto mut = resolved.get_and_mutate();
1432 assertf(resolved.get() == mut, "newly resolved expression must be unique");
1433 mut->env = nullptr;
1434
1435 // for constructor expr:
1436 // T x;
1437 // x{};
1438 // results in:
1439 // T x;
1440 // T & tmp;
1441 // &tmp = &x, ?{}(tmp), tmp
1442 ast::CommaExpr * commaExpr = new ast::CommaExpr(loc, resolved, new ast::CommaExpr(loc, mutCallExpr, new ast::VariableExpr(loc, tmp ) ) );
1443 commaExpr->env = env;
1444 return commaExpr;
1445 }
1446 } // namespace
1447} // namespace InitTweak
1448
1449// Local Variables: //
1450// tab-width: 4 //
1451// mode: c++ //
1452// compile-command: "make install" //
1453// End: //
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