source: src/InitTweak/FixInit.cc@ e85a8631

ADT aaron-thesis arm-eh ast-experimental cleanup-dtors ctor deferred_resn demangler enum forall-pointer-decay jacob/cs343-translation jenkins-sandbox new-ast new-ast-unique-expr new-env no_list persistent-indexer pthread-emulation qualifiedEnum resolv-new with_gc
Last change on this file since e85a8631 was f9cebb5, checked in by Rob Schluntz <rschlunt@…>, 9 years ago

add gcc attributes to ObjectDecl, hoist destructed static variables, add breaks to end of generated switch
  • Property mode set to 100644
File size: 29.6 KB
RevLine 
[71f4e4f]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.h --
8//
9// Author : Rob Schluntz
10// Created On : Wed Jan 13 16:29:30 2016
[adcc065]11// Last Modified By : Peter A. Buhr
[4e06c1e]12// Last Modified On : Tue Jul 12 17:41:15 2016
13// Update Count : 34
[71f4e4f]14//
15
16#include <stack>
17#include <list>
[c2931ea]18#include <iterator>
19#include <algorithm>
[7b3f66b]20#include "InitTweak.h"
[6cf27a07]21#include "FixInit.h"
22#include "FixGlobalInit.h"
[db4ecc5]23#include "ResolvExpr/Resolver.h"
[845cedc]24#include "ResolvExpr/typeops.h"
[71f4e4f]25#include "SynTree/Declaration.h"
26#include "SynTree/Type.h"
27#include "SynTree/Expression.h"
[f9cebb5]28#include "SynTree/Attribute.h"
[71f4e4f]29#include "SynTree/Statement.h"
30#include "SynTree/Initializer.h"
31#include "SynTree/Mutator.h"
[db4ecc5]32#include "SymTab/Indexer.h"
[71f4e4f]33#include "GenPoly/PolyMutator.h"
[c2931ea]34#include "SynTree/AddStmtVisitor.h"
[71f4e4f]35
[845cedc]36bool ctordtorp = false;
[c2931ea]37bool ctorp = false;
38bool cpctorp = false;
[e39aa0f]39bool dtorp = false;
[845cedc]40#define PRINT( text ) if ( ctordtorp ) { text }
[c2931ea]41#define CP_CTOR_PRINT( text ) if ( ctordtorp || cpctorp ) { text }
42#define DTOR_PRINT( text ) if ( ctordtorp || dtorp ) { text }
[845cedc]43
[71f4e4f]44namespace InitTweak {
45 namespace {
46 const std::list<Label> noLabels;
[e0323a2]47 const std::list<Expression*> noDesignators;
[71f4e4f]48
[c2931ea]49 class InsertImplicitCalls : public GenPoly::PolyMutator {
50 public:
[adcc065]51 /// wrap function application expressions as ImplicitCopyCtorExpr nodes so that it is easy to identify which
52 /// function calls need their parameters to be copy constructed
[c2931ea]53 static void insert( std::list< Declaration * > & translationUnit );
54
55 virtual Expression * mutate( ApplicationExpr * appExpr );
56 };
57
58 class ResolveCopyCtors : public SymTab::Indexer {
59 public:
[adcc065]60 /// generate temporary ObjectDecls for each argument and return value of each ImplicitCopyCtorExpr,
61 /// generate/resolve copy construction expressions for each, and generate/resolve destructors for both
62 /// arguments and return value temporaries
[c2931ea]63 static void resolveImplicitCalls( std::list< Declaration * > & translationUnit );
64
65 virtual void visit( ImplicitCopyCtorExpr * impCpCtorExpr );
66
67 /// create and resolve ctor/dtor expression: fname(var, [cpArg])
68 ApplicationExpr * makeCtorDtor( const std::string & fname, ObjectDecl * var, Expression * cpArg = NULL );
69 /// true if type does not need to be copy constructed to ensure correctness
70 bool skipCopyConstruct( Type * );
71 private:
72 TypeSubstitution * env;
73 };
74
75 /// collects constructed object decls - used as a base class
76 class ObjDeclCollector : public AddStmtVisitor {
77 public:
78 typedef AddStmtVisitor Parent;
79 using Parent::visit;
80 typedef std::set< ObjectDecl * > ObjectSet;
81 virtual void visit( CompoundStmt *compoundStmt );
82 virtual void visit( DeclStmt *stmt );
83 protected:
84 ObjectSet curVars;
85 };
86
[6cf27a07]87 // debug
[c2931ea]88 struct printSet {
89 typedef ObjDeclCollector::ObjectSet ObjectSet;
90 printSet( const ObjectSet & objs ) : objs( objs ) {}
91 const ObjectSet & objs;
92 };
93 std::ostream & operator<<( std::ostream & out, const printSet & set) {
94 out << "{ ";
95 for ( ObjectDecl * obj : set.objs ) {
96 out << obj->get_name() << ", " ;
[adcc065]97 } // for
[c2931ea]98 out << " }";
99 return out;
100 }
101
102 class LabelFinder : public ObjDeclCollector {
103 public:
104 typedef ObjDeclCollector Parent;
105 typedef std::map< Label, ObjectSet > LabelMap;
106 // map of Label -> live variables at that label
107 LabelMap vars;
108
109 void handleStmt( Statement * stmt );
110
111 // xxx - This needs to be done better.
[adcc065]112 // allow some generalization among different kinds of nodes with with similar parentage (e.g. all
113 // expressions, all statements, etc.) important to have this to provide a single entry point so that as new
114 // subclasses are added, there is only one place that the code has to be updated, rather than ensure that
115 // every specialized class knows about every new kind of statement that might be added.
[c2931ea]116 virtual void visit( CompoundStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
117 virtual void visit( ExprStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
118 virtual void visit( AsmStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
119 virtual void visit( IfStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
120 virtual void visit( WhileStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
121 virtual void visit( ForStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
122 virtual void visit( SwitchStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
123 virtual void visit( CaseStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
124 virtual void visit( BranchStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
125 virtual void visit( ReturnStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
126 virtual void visit( TryStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
127 virtual void visit( CatchStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
128 virtual void visit( FinallyStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
129 virtual void visit( NullStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
130 virtual void visit( DeclStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
131 virtual void visit( ImplicitCtorDtorStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
132 };
133
134 class InsertDtors : public ObjDeclCollector {
135 public:
[adcc065]136 /// insert destructor calls at the appropriate places. must happen before CtorInit nodes are removed
137 /// (currently by FixInit)
[c2931ea]138 static void insert( std::list< Declaration * > & translationUnit );
139
140 typedef ObjDeclCollector Parent;
141 typedef std::list< ObjectDecl * > OrderedDecls;
142 typedef std::list< OrderedDecls > OrderedDeclsStack;
143
144 InsertDtors( LabelFinder & finder ) : labelVars( finder.vars ) {}
145
146 virtual void visit( ObjectDecl * objDecl );
147
148 virtual void visit( CompoundStmt * compoundStmt );
149 virtual void visit( ReturnStmt * returnStmt );
150 virtual void visit( BranchStmt * stmt );
151 private:
152 void handleGoto( BranchStmt * stmt );
153
154 LabelFinder::LabelMap & labelVars;
155 OrderedDeclsStack reverseDeclOrder;
156 };
157
158 class FixInit : public GenPoly::PolyMutator {
159 public:
160 /// expand each object declaration to use its constructor after it is declared.
161 static void fixInitializers( std::list< Declaration * > &translationUnit );
162
163 virtual DeclarationWithType * mutate( ObjectDecl *objDecl );
[72e9222]164
165 std::list< Declaration * > staticDtorDecls;
[c2931ea]166 };
167
168 class FixCopyCtors : public GenPoly::PolyMutator {
169 public:
[adcc065]170 /// expand ImplicitCopyCtorExpr nodes into the temporary declarations, copy constructors, call expression,
171 /// and destructors
[c2931ea]172 static void fixCopyCtors( std::list< Declaration * > &translationUnit );
173
174 virtual Expression * mutate( ImplicitCopyCtorExpr * impCpCtorExpr );
175 };
176 } // namespace
[db4ecc5]177
[6cf27a07]178 void fix( std::list< Declaration * > & translationUnit, const std::string & filename, bool inLibrary ) {
179 // fixes ConstructorInit for global variables. should happen before fixInitializers.
180 InitTweak::fixGlobalInit( translationUnit, filename, inLibrary );
181
[db4ecc5]182 InsertImplicitCalls::insert( translationUnit );
183 ResolveCopyCtors::resolveImplicitCalls( translationUnit );
[c2931ea]184 InsertDtors::insert( translationUnit );
[71f4e4f]185 FixInit::fixInitializers( translationUnit );
[c2931ea]186
[db4ecc5]187 // FixCopyCtors must happen after FixInit, so that destructors are placed correctly
188 FixCopyCtors::fixCopyCtors( translationUnit );
189 }
190
[c2931ea]191 namespace {
192 void InsertImplicitCalls::insert( std::list< Declaration * > & translationUnit ) {
193 InsertImplicitCalls inserter;
194 mutateAll( translationUnit, inserter );
195 }
[db4ecc5]196
[c2931ea]197 void ResolveCopyCtors::resolveImplicitCalls( std::list< Declaration * > & translationUnit ) {
198 ResolveCopyCtors resolver;
199 acceptAll( translationUnit, resolver );
200 }
[71f4e4f]201
[c2931ea]202 void FixInit::fixInitializers( std::list< Declaration * > & translationUnit ) {
203 FixInit fixer;
[72e9222]204
205 // can't use mutateAll, because need to insert declarations at top-level
206 // can't use DeclMutator, because sometimes need to insert IfStmt, etc.
207 SemanticError errors;
208 for ( std::list< Declaration * >::iterator i = translationUnit.begin(); i != translationUnit.end(); ++i ) {
209 try {
210 *i = maybeMutate( *i, fixer );
[f9cebb5]211 translationUnit.splice( i, fixer.staticDtorDecls );
[72e9222]212 } catch( SemanticError &e ) {
213 errors.append( e );
214 } // try
215 } // for
216 if ( ! errors.isEmpty() ) {
217 throw errors;
218 } // if
[c2931ea]219 }
[71f4e4f]220
[c2931ea]221 void InsertDtors::insert( std::list< Declaration * > & translationUnit ) {
222 LabelFinder finder;
223 InsertDtors inserter( finder );
224 acceptAll( translationUnit, finder );
225 acceptAll( translationUnit, inserter );
226 }
227
228 void FixCopyCtors::fixCopyCtors( std::list< Declaration * > & translationUnit ) {
229 FixCopyCtors fixer;
230 mutateAll( translationUnit, fixer );
231 }
[db4ecc5]232
[c2931ea]233 Expression * InsertImplicitCalls::mutate( ApplicationExpr * appExpr ) {
234 appExpr = dynamic_cast< ApplicationExpr * >( Mutator::mutate( appExpr ) );
235 assert( appExpr );
236
237 if ( VariableExpr * function = dynamic_cast< VariableExpr * > ( appExpr->get_function() ) ) {
238 if ( function->get_var()->get_linkage() == LinkageSpec::Intrinsic ) {
239 // optimization: don't need to copy construct in order to call intrinsic functions
240 return appExpr;
241 } else if ( DeclarationWithType * funcDecl = dynamic_cast< DeclarationWithType * > ( function->get_var() ) ) {
242 FunctionType * ftype = dynamic_cast< FunctionType * >( GenPoly::getFunctionType( funcDecl->get_type() ) );
243 assert( ftype );
244 if ( (funcDecl->get_name() == "?{}" || funcDecl->get_name() == "?=?") && ftype->get_parameters().size() == 2 ) {
245 Type * t1 = ftype->get_parameters().front()->get_type();
246 Type * t2 = ftype->get_parameters().back()->get_type();
247 PointerType * ptrType = dynamic_cast< PointerType * > ( t1 );
248 assert( ptrType );
249
250 if ( ResolvExpr::typesCompatible( ptrType->get_base(), t2, SymTab::Indexer() ) ) {
251 // optimization: don't need to copy construct in order to call a copy constructor or
252 // assignment operator
253 return appExpr;
[adcc065]254 } // if
[c2931ea]255 } else if ( funcDecl->get_name() == "^?{}" ) {
256 // correctness: never copy construct arguments to a destructor
[845cedc]257 return appExpr;
[adcc065]258 } // if
259 } // if
260 } // if
[c2931ea]261 CP_CTOR_PRINT( std::cerr << "InsertImplicitCalls: adding a wrapper " << appExpr << std::endl; )
262
263 // wrap each function call so that it is easy to identify nodes that have to be copy constructed
264 ImplicitCopyCtorExpr * expr = new ImplicitCopyCtorExpr( appExpr );
265 // save the type substitution onto the new node so that it is easy to find.
266 // Ensure it is not deleted with the ImplicitCopyCtorExpr by removing it before deletion.
267 // The substitution is needed to obtain the type of temporary variables so that copy constructor
268 // calls can be resolved. Normally this is what PolyMutator is for, but the pass that resolves
269 // copy constructor calls must be an Indexer. We could alternatively make a PolyIndexer which
270 // saves the environment, or compute the types of temporaries here, but it's much simpler to
271 // save the environment here, and more cohesive to compute temporary variables and resolve copy
272 // constructor calls together.
273 assert( env );
274 expr->set_env( env );
275 return expr;
[db4ecc5]276 }
277
[c2931ea]278 bool ResolveCopyCtors::skipCopyConstruct( Type * type ) {
279 return dynamic_cast< VarArgsType * >( type ) || GenPoly::getFunctionType( type );
280 }
281
282 ApplicationExpr * ResolveCopyCtors::makeCtorDtor( const std::string & fname, ObjectDecl * var, Expression * cpArg ) {
283 assert( var );
284 UntypedExpr * untyped = new UntypedExpr( new NameExpr( fname ) );
285 untyped->get_args().push_back( new AddressExpr( new VariableExpr( var ) ) );
286 if (cpArg) untyped->get_args().push_back( cpArg );
287
288 // resolve copy constructor
[adcc065]289 // should only be one alternative for copy ctor and dtor expressions, since all arguments are fixed
290 // (VariableExpr and already resolved expression)
[c2931ea]291 CP_CTOR_PRINT( std::cerr << "ResolvingCtorDtor " << untyped << std::endl; )
292 ApplicationExpr * resolved = dynamic_cast< ApplicationExpr * >( ResolvExpr::findVoidExpression( untyped, *this ) );
293 if ( resolved->get_env() ) {
294 env->add( *resolved->get_env() );
[adcc065]295 } // if
[cf18eea]296
[c2931ea]297 assert( resolved );
298 delete untyped;
299 return resolved;
[540de412]300 }
[db4ecc5]301
[c2931ea]302 void ResolveCopyCtors::visit( ImplicitCopyCtorExpr *impCpCtorExpr ) {
303 static UniqueName tempNamer("_tmp_cp");
304 static UniqueName retNamer("_tmp_cp_ret");
305
306 CP_CTOR_PRINT( std::cerr << "ResolveCopyCtors: " << impCpCtorExpr << std::endl; )
307 Visitor::visit( impCpCtorExpr );
308 env = impCpCtorExpr->get_env(); // xxx - maybe we really should just have a PolyIndexer...
309
310 ApplicationExpr * appExpr = impCpCtorExpr->get_callExpr();
311
312 // take each argument and attempt to copy construct it.
313 for ( Expression * & arg : appExpr->get_args() ) {
314 CP_CTOR_PRINT( std::cerr << "Type Substitution: " << *impCpCtorExpr->get_env() << std::endl; )
315 // xxx - need to handle tuple arguments
316 assert( ! arg->get_results().empty() );
317 Type * result = arg->get_results().front();
318 if ( skipCopyConstruct( result ) ) continue; // skip certain non-copyable types
319 // type may involve type variables, so apply type substitution to get temporary variable's actual type
320 result = result->clone();
321 impCpCtorExpr->get_env()->apply( result );
322 ObjectDecl * tmp = new ObjectDecl( tempNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, 0, result, 0 );
323 tmp->get_type()->set_isConst( false );
324
325 // create and resolve copy constructor
326 CP_CTOR_PRINT( std::cerr << "makeCtorDtor for an argument" << std::endl; )
327 ApplicationExpr * cpCtor = makeCtorDtor( "?{}", tmp, arg );
328
329 // if the chosen constructor is intrinsic, the copy is unnecessary, so
330 // don't create the temporary and don't call the copy constructor
331 VariableExpr * function = dynamic_cast< VariableExpr * >( cpCtor->get_function() );
332 assert( function );
333 if ( function->get_var()->get_linkage() != LinkageSpec::Intrinsic ) {
334 // replace argument to function call with temporary
335 arg = new CommaExpr( cpCtor, new VariableExpr( tmp ) );
336 impCpCtorExpr->get_tempDecls().push_back( tmp );
337 impCpCtorExpr->get_dtors().push_front( makeCtorDtor( "^?{}", tmp ) );
[adcc065]338 } // if
339 } // for
[db4ecc5]340
[adcc065]341 // each return value from the call needs to be connected with an ObjectDecl at the call site, which is
342 // initialized with the return value and is destructed later
[c2931ea]343 // xxx - handle multiple return values
344 ApplicationExpr * callExpr = impCpCtorExpr->get_callExpr();
[adcc065]345 // xxx - is this right? callExpr may not have the right environment, because it was attached at a higher
346 // level. Trying to pass that environment along.
[c2931ea]347 callExpr->set_env( impCpCtorExpr->get_env()->clone() );
348 for ( Type * result : appExpr->get_results() ) {
349 result = result->clone();
350 impCpCtorExpr->get_env()->apply( result );
351 ObjectDecl * ret = new ObjectDecl( retNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, 0, result, 0 );
352 ret->get_type()->set_isConst( false );
353 impCpCtorExpr->get_returnDecls().push_back( ret );
354 CP_CTOR_PRINT( std::cerr << "makeCtorDtor for a return" << std::endl; )
355 impCpCtorExpr->get_dtors().push_front( makeCtorDtor( "^?{}", ret ) );
[adcc065]356 } // for
[c2931ea]357 CP_CTOR_PRINT( std::cerr << "after Resolving: " << impCpCtorExpr << std::endl; )
[db4ecc5]358 }
359
360
[c2931ea]361 Expression * FixCopyCtors::mutate( ImplicitCopyCtorExpr * impCpCtorExpr ) {
362 CP_CTOR_PRINT( std::cerr << "FixCopyCtors: " << impCpCtorExpr << std::endl; )
363
364 impCpCtorExpr = dynamic_cast< ImplicitCopyCtorExpr * >( Mutator::mutate( impCpCtorExpr ) );
365 assert( impCpCtorExpr );
[db4ecc5]366
[c2931ea]367 std::list< ObjectDecl * > & tempDecls = impCpCtorExpr->get_tempDecls();
368 std::list< ObjectDecl * > & returnDecls = impCpCtorExpr->get_returnDecls();
369 std::list< Expression * > & dtors = impCpCtorExpr->get_dtors();
[845cedc]370
[c2931ea]371 // add all temporary declarations and their constructors
372 for ( ObjectDecl * obj : tempDecls ) {
373 stmtsToAdd.push_back( new DeclStmt( noLabels, obj ) );
[adcc065]374 } // for
[c2931ea]375 for ( ObjectDecl * obj : returnDecls ) {
376 stmtsToAdd.push_back( new DeclStmt( noLabels, obj ) );
[adcc065]377 } // for
[db4ecc5]378
[c2931ea]379 // add destructors after current statement
380 for ( Expression * dtor : dtors ) {
381 stmtsToAddAfter.push_back( new ExprStmt( noLabels, dtor ) );
[adcc065]382 } // for
[db4ecc5]383
[c2931ea]384 // xxx - update to work with multiple return values
385 ObjectDecl * returnDecl = returnDecls.empty() ? NULL : returnDecls.front();
386 Expression * callExpr = impCpCtorExpr->get_callExpr();
387
388 CP_CTOR_PRINT( std::cerr << "Coming out the back..." << impCpCtorExpr << std::endl; )
389
390 // detach fields from wrapper node so that it can be deleted without deleting too much
391 dtors.clear();
392 tempDecls.clear();
393 returnDecls.clear();
394 impCpCtorExpr->set_callExpr( NULL );
395 impCpCtorExpr->set_env( NULL );
396 delete impCpCtorExpr;
397
398 if ( returnDecl ) {
399 UntypedExpr * assign = new UntypedExpr( new NameExpr( "?=?" ) );
400 assign->get_args().push_back( new VariableExpr( returnDecl ) );
401 assign->get_args().push_back( callExpr );
402 // know the result type of the assignment is the type of the LHS (minus the pointer), so
403 // add that onto the assignment expression so that later steps have the necessary information
404 assign->add_result( returnDecl->get_type()->clone() );
405
406 Expression * retExpr = new CommaExpr( assign, new VariableExpr( returnDecl ) );
407 if ( callExpr->get_results().front()->get_isLvalue() ) {
[adcc065]408 // lvalue returning functions are funny. Lvalue.cc inserts a *? in front of any lvalue returning
409 // non-intrinsic function. Add an AddressExpr to the call to negate the derefence and change the
410 // type of the return temporary from T to T* to properly capture the return value. Then dereference
411 // the result of the comma expression, since the lvalue returning call was originally wrapped with
412 // an AddressExpr. Effectively, this turns
[c2931ea]413 // lvalue T f();
414 // &*f()
415 // into
416 // T * tmp_cp_retN;
417 // tmp_cp_ret_N = &*(tmp_cp_ret_N = &*f(), tmp_cp_ret);
418 // which work out in terms of types, but is pretty messy. It would be nice to find a better way.
419 assign->get_args().back() = new AddressExpr( assign->get_args().back() );
420
421 Type * resultType = returnDecl->get_type()->clone();
422 returnDecl->set_type( new PointerType( Type::Qualifiers(), returnDecl->get_type() ) );
423 UntypedExpr * deref = new UntypedExpr( new NameExpr( "*?" ) );
424 deref->get_args().push_back( retExpr );
425 deref->add_result( resultType );
426 retExpr = deref;
[adcc065]427 } // if
[c2931ea]428 // xxx - might need to set env on retExpr...
429 // retExpr->set_env( env->clone() );
430 return retExpr;
431 } else {
432 return callExpr;
[adcc065]433 } // if
[4ffdd63]434 }
[c2931ea]435
436 DeclarationWithType *FixInit::mutate( ObjectDecl *objDecl ) {
[adcc065]437 // first recursively handle pieces of ObjectDecl so that they aren't missed by other visitors when the init
438 // is removed from the ObjectDecl
[c2931ea]439 objDecl = dynamic_cast< ObjectDecl * >( Mutator::mutate( objDecl ) );
440
441 if ( ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() ) ) {
442 // a decision should have been made by the resolver, so ctor and init are not both non-NULL
443 assert( ! ctorInit->get_ctor() || ! ctorInit->get_init() );
444 if ( Statement * ctor = ctorInit->get_ctor() ) {
445 if ( objDecl->get_storageClass() == DeclarationNode::Static ) {
[72e9222]446 // originally wanted to take advantage of gcc nested functions, but
[f9cebb5]447 // we get memory errors with this approach. To remedy this, the static
448 // variable is hoisted when the destructor needs to be called.
[72e9222]449 //
[c2931ea]450 // generate:
[f9cebb5]451 // static T __objName_static_varN;
[72e9222]452 // void __objName_dtor_atexitN() {
[f9cebb5]453 // __dtor__...;
[72e9222]454 // }
455 // int f(...) {
456 // ...
457 // static bool __objName_uninitialized = true;
458 // if (__objName_uninitialized) {
459 // __ctor(__objName);
460 // __objName_uninitialized = false;
[f9cebb5]461 // atexit(__objName_dtor_atexitN);
[c2931ea]462 // }
[72e9222]463 // ...
[c2931ea]464 // }
465
[72e9222]466 static UniqueName dtorCallerNamer( "_dtor_atexit" );
467
468 // static bool __objName_uninitialized = true
[c2931ea]469 BasicType * boolType = new BasicType( Type::Qualifiers(), BasicType::Bool );
470 SingleInit * boolInitExpr = new SingleInit( new ConstantExpr( Constant( boolType->clone(), "1" ) ), noDesignators );
471 ObjectDecl * isUninitializedVar = new ObjectDecl( objDecl->get_mangleName() + "_uninitialized", DeclarationNode::Static, LinkageSpec::Cforall, 0, boolType, boolInitExpr );
472 isUninitializedVar->fixUniqueId();
473
474 // __objName_uninitialized = false;
475 UntypedExpr * setTrue = new UntypedExpr( new NameExpr( "?=?" ) );
476 setTrue->get_args().push_back( new VariableExpr( isUninitializedVar ) );
477 setTrue->get_args().push_back( new ConstantExpr( Constant( boolType->clone(), "0" ) ) );
478
479 // generate body of if
480 CompoundStmt * initStmts = new CompoundStmt( noLabels );
481 std::list< Statement * > & body = initStmts->get_kids();
482 body.push_back( ctor );
483 body.push_back( new ExprStmt( noLabels, setTrue ) );
484
485 // put it all together
486 IfStmt * ifStmt = new IfStmt( noLabels, new VariableExpr( isUninitializedVar ), initStmts, 0 );
487 stmtsToAddAfter.push_back( new DeclStmt( noLabels, isUninitializedVar ) );
488 stmtsToAddAfter.push_back( ifStmt );
[72e9222]489
[f9cebb5]490 if ( ctorInit->get_dtor() ) {
491 // if the object has a non-trivial destructor, have to
492 // hoist it and the object into the global space and
493 // call the destructor function with atexit.
494
495 Statement * dtorStmt = ctorInit->get_dtor()->clone();
496
497 // void __objName_dtor_atexitN(...) {...}
498 FunctionDecl * dtorCaller = new FunctionDecl( objDecl->get_mangleName() + dtorCallerNamer.newName(), DeclarationNode::Static, LinkageSpec::C, new FunctionType( Type::Qualifiers(), false ), new CompoundStmt( noLabels ), false, false );
499 dtorCaller->fixUniqueId();
500 dtorCaller->get_statements()->get_kids().push_back( dtorStmt );
501
502 // atexit(dtor_atexit);
503 UntypedExpr * callAtexit = new UntypedExpr( new NameExpr( "atexit" ) );
504 callAtexit->get_args().push_back( new VariableExpr( dtorCaller ) );
505
506 body.push_back( new ExprStmt( noLabels, callAtexit ) );
507
508 // hoist variable and dtor caller decls to list of decls that will be added into global scope
509 staticDtorDecls.push_back( objDecl );
510 staticDtorDecls.push_back( dtorCaller );
511
512 // need to rename object uniquely since it now appears
513 // at global scope and there could be multiple function-scoped
514 // static variables with the same name in different functions.
515 static UniqueName staticNamer( "_static_var" );
516 objDecl->set_mangleName( objDecl->get_mangleName() + staticNamer.newName() );
517
518 objDecl->set_init( NULL );
519 ctorInit->set_ctor( NULL );
520 delete ctorInit;
521
522 // xxx - temporary hack: need to return a declaration, but want to hoist the current object out of this scope
523 // create a new object which is never used
524 static UniqueName dummyNamer( "_dummy" );
525 ObjectDecl * dummy = new ObjectDecl( dummyNamer.newName(), DeclarationNode::Static, LinkageSpec::Cforall, 0, new PointerType( Type::Qualifiers(), new VoidType( Type::Qualifiers() ) ), 0, std::list< Attribute * >{ new Attribute("unused") } );
526 return dummy;
527 }
[c2931ea]528 } else {
529 stmtsToAddAfter.push_back( ctor );
[adcc065]530 } // if
[c2931ea]531 objDecl->set_init( NULL );
532 ctorInit->set_ctor( NULL );
533 } else if ( Initializer * init = ctorInit->get_init() ) {
534 objDecl->set_init( init );
535 ctorInit->set_init( NULL );
536 } else {
537 // no constructor and no initializer, which is okay
538 objDecl->set_init( NULL );
[adcc065]539 } // if
[c2931ea]540 delete ctorInit;
[adcc065]541 } // if
[c2931ea]542 return objDecl;
[db4ecc5]543 }
544
[c2931ea]545 void ObjDeclCollector::visit( CompoundStmt *compoundStmt ) {
546 std::set< ObjectDecl * > prevVars = curVars;
547 Parent::visit( compoundStmt );
548 curVars = prevVars;
[db4ecc5]549 }
550
[c2931ea]551 void ObjDeclCollector::visit( DeclStmt *stmt ) {
[4b2589a]552 // keep track of all variables currently in scope
[c2931ea]553 if ( ObjectDecl * objDecl = dynamic_cast< ObjectDecl * > ( stmt->get_decl() ) ) {
554 curVars.insert( objDecl );
[adcc065]555 } // if
[e39aa0f]556 Parent::visit( stmt );
[db4ecc5]557 }
558
[c2931ea]559 void LabelFinder::handleStmt( Statement * stmt ) {
[4b2589a]560 // for each label, remember the variables in scope at that label.
[c2931ea]561 for ( Label l : stmt->get_labels() ) {
562 vars[l] = curVars;
[adcc065]563 } // for
[71f4e4f]564 }
[f1e012b]565
[ec79847]566 template<typename Iterator, typename OutputIterator>
567 void insertDtors( Iterator begin, Iterator end, OutputIterator out ) {
568 for ( Iterator it = begin ; it != end ; ++it ) {
[adcc065]569 // extract destructor statement from the object decl and insert it into the output. Note that this is
570 // only called on lists of non-static objects with implicit non-intrinsic dtors, so if the user manually
571 // calls an intrinsic dtor then the call must (and will) still be generated since the argument may
572 // contain side effects.
[c2931ea]573 ObjectDecl * objDecl = *it;
574 ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() );
575 assert( ctorInit && ctorInit->get_dtor() );
576 *out++ = ctorInit->get_dtor()->clone();
[adcc065]577 } // for
[f1e012b]578 }
[39786813]579
[c2931ea]580 void InsertDtors::visit( ObjectDecl * objDecl ) {
581 // remember non-static destructed objects so that their destructors can be inserted later
582 if ( objDecl->get_storageClass() != DeclarationNode::Static ) {
583 if ( ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() ) ) {
584 // a decision should have been made by the resolver, so ctor and init are not both non-NULL
585 assert( ! ctorInit->get_ctor() || ! ctorInit->get_init() );
586 Statement * dtor = ctorInit->get_dtor();
[f9cebb5]587 if ( dtor && ! isIntrinsicSingleArgCallStmt( dtor ) ) {
[c2931ea]588 // don't need to call intrinsic dtor, because it does nothing, but
589 // non-intrinsic dtors must be called
590 reverseDeclOrder.front().push_front( objDecl );
[adcc065]591 } // if
592 } // if
593 } // if
[c2931ea]594 Parent::visit( objDecl );
595 }
[39786813]596
[c2931ea]597 void InsertDtors::visit( CompoundStmt * compoundStmt ) {
[adcc065]598 // visit statements - this will also populate reverseDeclOrder list. don't want to dump all destructors
599 // when block is left, just the destructors associated with variables defined in this block, so push a new
600 // list to the top of the stack so that we can differentiate scopes
[c2931ea]601 reverseDeclOrder.push_front( OrderedDecls() );
602 Parent::visit( compoundStmt );
[39786813]603
[4b2589a]604 // add destructors for the current scope that we're exiting
[c2931ea]605 std::list< Statement * > & statements = compoundStmt->get_kids();
606 insertDtors( reverseDeclOrder.front().begin(), reverseDeclOrder.front().end(), back_inserter( statements ) );
607 reverseDeclOrder.pop_front();
[39786813]608 }
609
[c2931ea]610 void InsertDtors::visit( ReturnStmt * returnStmt ) {
[4b2589a]611 // return exits all scopes, so dump destructors for all scopes
[c2931ea]612 for ( OrderedDecls & od : reverseDeclOrder ) {
613 insertDtors( od.begin(), od.end(), back_inserter( stmtsToAdd ) );
[adcc065]614 } // for
[39786813]615 }
[f1e012b]616
[adcc065]617 // Handle break/continue/goto in the same manner as C++. Basic idea: any objects that are in scope at the
618 // BranchStmt but not at the labelled (target) statement must be destructed. If there are any objects in scope
619 // at the target location but not at the BranchStmt then those objects would be uninitialized so notify the user
620 // of the error. See C++ Reference 6.6 Jump Statements for details.
[c2931ea]621 void InsertDtors::handleGoto( BranchStmt * stmt ) {
[e39aa0f]622 assert( stmt->get_target() != "" && "BranchStmt missing a label" );
[c2931ea]623 // S_L = lvars = set of objects in scope at label definition
624 // S_G = curVars = set of objects in scope at goto statement
625 ObjectSet & lvars = labelVars[ stmt->get_target() ];
626
627 DTOR_PRINT(
628 std::cerr << "at goto label: " << stmt->get_target().get_name() << std::endl;
629 std::cerr << "S_G = " << printSet( curVars ) << std::endl;
630 std::cerr << "S_L = " << printSet( lvars ) << std::endl;
631 )
632
633 ObjectSet diff;
634 // S_L-S_G results in set of objects whose construction is skipped - it's an error if this set is non-empty
635 std::set_difference( lvars.begin(), lvars.end(), curVars.begin(), curVars.end(), std::inserter( diff, diff.begin() ) );
636 DTOR_PRINT(
637 std::cerr << "S_L-S_G = " << printSet( diff ) << std::endl;
638 )
639 if ( ! diff.empty() ) {
640 throw SemanticError( std::string("jump to label '") + stmt->get_target().get_name() + "' crosses initialization of " + (*diff.begin())->get_name() + " ", stmt );
[adcc065]641 } // if
[c2931ea]642 // S_G-S_L results in set of objects that must be destructed
643 diff.clear();
644 std::set_difference( curVars.begin(), curVars.end(), lvars.begin(), lvars.end(), std::inserter( diff, diff.end() ) );
645 DTOR_PRINT(
646 std::cerr << "S_G-S_L = " << printSet( diff ) << std::endl;
647 )
648 if ( ! diff.empty() ) {
649 // go through decl ordered list of objectdecl. for each element that occurs in diff, output destructor
650 OrderedDecls ordered;
651 for ( OrderedDecls & rdo : reverseDeclOrder ) {
652 // add elements from reverseDeclOrder into ordered if they occur in diff - it is key that this happens in reverse declaration order.
653 copy_if( rdo.begin(), rdo.end(), back_inserter( ordered ), [&]( ObjectDecl * objDecl ) { return diff.count( objDecl ); } );
[adcc065]654 } // for
[c2931ea]655 insertDtors( ordered.begin(), ordered.end(), back_inserter( stmtsToAdd ) );
[adcc065]656 } // if
[c2931ea]657 }
[39786813]658
[c2931ea]659 void InsertDtors::visit( BranchStmt * stmt ) {
660 switch( stmt->get_type() ) {
[adcc065]661 case BranchStmt::Continue:
662 case BranchStmt::Break:
663 // could optimize the break/continue case, because the S_L-S_G check is unnecessary (this set should
664 // always be empty), but it serves as a small sanity check.
665 case BranchStmt::Goto:
666 handleGoto( stmt );
667 break;
668 default:
669 assert( false );
670 } // switch
[c2931ea]671 }
672 } // namespace
[71f4e4f]673} // namespace InitTweak
674
675// Local Variables: //
676// tab-width: 4 //
677// mode: c++ //
678// compile-command: "make install" //
679// End: //
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