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source: src/Virtual/VirtualDtor.cpp @ cad8c88

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1	//
2	// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
3	//
4	// The contents of this file are covered under the licence agreement in the
5	// file "LICENCE" distributed with Cforall.
6	//
7	// VirtualDtor.cpp -- generate code needed by the actor system
8	//
9	// Author : Colby Parsons
10	// Created On : Tues Mar 14 15:16:42 2023
11	// Last Modified By : Colby Parsons
12	// Last Modified On : Tues Mar 14 15:16:42 2023
13	// Update Count : 0
14	//
15
16	#include "AST/Print.hpp"
17	#include "AST/Decl.hpp"
18	#include "AST/Pass.hpp"
19	#include "AST/Type.hpp"
20	#include "AST/Stmt.hpp"
21	#include "AST/TranslationUnit.hpp"
22	#include "AST/Expr.hpp"
23	#include <algorithm>
24	using namespace ast;
25	using namespace std;
26
27	namespace Virtual {
28
29	struct CtorDtor {
30	FunctionDecl * dtorSetup; // dtor init routine to add after last dtor for a struct
31	FunctionDecl * deleteFn;
32	FunctionDecl * lastDtor; // pointer to last occurence of dtor to know where to insert after
33
34	CtorDtor() : dtorSetup(nullptr), deleteFn(nullptr), lastDtor(nullptr) {}
35	};
36
37	class CtorDtorTable {
38	unordered_map<const StructDecl *, CtorDtor> & structMap;
39
40	public:
41	// if dtor is last dtor for this decl return the routine to add afterwards
42	// otherwise return nullptr
43	FunctionDecl * getToAddLater( const StructDecl * decl, FunctionDecl * dtor, FunctionDecl ** retDeleteFn ) {
44	auto iter = structMap.find( decl );
45	if ( iter == structMap.end() \|\| iter->second.lastDtor != dtor ) return nullptr; // check if this is needed
46	*retDeleteFn = iter->second.deleteFn;
47	return iter->second.dtorSetup;
48	}
49
50	// return if the dtorSetup field has been defined for this decl
51	bool inTable( const StructDecl * decl ) {
52	auto iter = structMap.find( decl );
53	return iter->second.dtorSetup != nullptr;
54	}
55
56	void addLater( const StructDecl * decl, FunctionDecl * dtorSetup, FunctionDecl * deleteFn ) {
57	auto iter = structMap.find( decl );
58	iter->second.dtorSetup = dtorSetup;
59	iter->second.deleteFn = deleteFn;
60	}
61
62	void addDtor( const StructDecl * decl, FunctionDecl * dtor ) {
63	auto iter = structMap.find( decl );
64	iter->second.lastDtor = dtor;
65	}
66
67	CtorDtorTable( unordered_map<const StructDecl *, CtorDtor> & structMap ) : structMap(structMap) {}
68	};
69
70	struct CollectStructDecls : public ast::WithGuards {
71	unordered_map<const StructDecl *, CtorDtor> & structDecls;
72	StructDecl * parentDecl;
73	bool insideStruct = false;
74	bool namedDecl = false;
75
76	const StructDecl ** virtualDtor;
77
78	// finds and sets a ptr to the actor, message, and request structs, which are needed in the next pass
79	void previsit( const StructDecl * decl ) {
80	if ( !decl->body ) return;
81	if( decl->name == "virtual_dtor" ) {
82	structDecls.emplace( make_pair( decl, CtorDtor() ) );
83	*virtualDtor = decl;
84	} else {
85	GuardValue(insideStruct);
86	insideStruct = true;
87	parentDecl = mutate( decl );
88	}
89	}
90
91	// this catches structs of the form:
92	// struct derived_type { virtual_dtor a; };
93	// since they should be:
94	// struct derived_type { inline virtual_dtor; };
95	void previsit ( const ObjectDecl * decl ) {
96	if ( insideStruct && ! decl->name.empty() ) {
97	GuardValue(namedDecl);
98	namedDecl = true;
99	}
100	}
101
102	// this collects the derived actor and message struct decl ptrs
103	void postvisit( const StructInstType * node ) {
104	if ( ! *virtualDtor ) return;
105	if ( insideStruct && !namedDecl ) {
106	auto structIter = structDecls.find( node->aggr() );
107	if ( structIter != structDecls.end() )
108	structDecls.emplace( make_pair( parentDecl, CtorDtor() ) );
109	}
110	}
111
112	public:
113	CollectStructDecls( unordered_map<const StructDecl , CtorDtor> & structDecls, const StructDecl * virtualDtor ):
114	structDecls( structDecls ), virtualDtor(virtualDtor) {}
115	};
116
117	// generates the forward decl of virtual dtor setting routine and delete routine
118	// generates the call to the virtual dtor routine in each appropriate ctor
119	// collects data needed for next pass that does the circular defn resolution
120	// for dtor setters and delete fns (via table above)
121	struct GenFuncsCreateTables : public ast::WithDeclsToAdd<> {
122	unordered_map<const StructDecl *, CtorDtor> & structDecls;
123	CtorDtorTable & torDecls;
124	const StructDecl ** virtualDtor;
125
126	// collects the dtor info for actors/messages
127	// gens the dtor fwd decl and dtor call in ctor
128	void previsit( const FunctionDecl * decl ) {
129	if ( (decl->name != "?{}" && decl->name != "^?{}") \|\| decl->params.size() == 0
130	\|\| !decl->stmts \|\| (decl->name == "^?{}" && decl->params.size() != 1)) return;
131
132	// the first param should be a reference
133	const ReferenceType * ref = dynamic_cast<const ReferenceType *>(decl->params.at(0)->get_type());
134	if ( !ref ) return;
135
136	// the reference should be to a struct instance
137	const StructInstType * instType = dynamic_cast<const StructInstType *>(ref->base.get());
138	if ( !instType ) return;
139
140	// return if not ctor/dtor for an actor or message
141	auto structIter = structDecls.find( instType->aggr() );
142	if ( structIter == structDecls.end() ) return;
143
144	// If first param not named we need to name it to use it
145	if ( decl->params.at(0)->name == "" )
146	mutate( decl->params.at(0).get() )->name = "__CFA_Virt_Dtor_param";
147
148	if ( decl->name == "^?{}") {
149	torDecls.addDtor( structIter->first, mutate( decl ) );
150
151	CompoundStmt * dtorBody = mutate( decl->stmts.get() );
152	// Adds the following to the start of any actor/message dtor:
153	// __CFA_dtor_shutdown( this );
154	dtorBody->push_front(
155	new IfStmt( decl->location,
156	new UntypedExpr (
157	decl->location,
158	new NameExpr( decl->location, "__CFA_dtor_shutdown" ),
159	{
160	new NameExpr( decl->location, decl->params.at(0)->name )
161	}
162	),
163	new ReturnStmt( decl->location, nullptr )
164	)
165	);
166	return;
167	}
168
169	// not dtor by this point so must be ctor
170	CompoundStmt * ctorBody = mutate( decl->stmts.get() );
171	// Adds the following to the end of any actor/message ctor:
172	// __CFA_set_dtor( this );
173	ctorBody->push_back( new ExprStmt(
174	decl->location,
175	new UntypedExpr (
176	decl->location,
177	new NameExpr( decl->location, "__CFA_set_dtor" ),
178	{
179	new NameExpr( decl->location, decl->params.at(0)->name )
180	}
181	)
182	));
183
184	if ( torDecls.inTable( structIter->first ) ) return;
185
186	// Generates the following:
187	// void __CFA_set_dtor( Derived_type & this ){
188	// void (*__my_dtor)( Derived_type & ) = ^?{};
189	// this.__virtual_dtor = (void (*)( Base_type & ))__my_dtor;
190	// this.__virtual_obj_start = (void *)(&this);
191	// }
192	CompoundStmt * setDtorBody = new CompoundStmt( decl->location );
193
194	// Function type is: (void (*)(Derived_type &))
195	FunctionType * derivedDtor = new FunctionType();
196	derivedDtor->params.push_back( ast::deepCopy( ref ) );
197
198	// Generates:
199	// void (*__my_dtor)( Derived_type & ) = ^?{};
200	setDtorBody->push_back( new DeclStmt(
201	decl->location,
202	new ObjectDecl(
203	decl->location,
204	"__my_dtor",
205	new PointerType( derivedDtor ),
206	new SingleInit( decl->location, new NameExpr( decl->location, "^?{}" ) )
207	)
208	));
209
210	// Function type is: (void (*)( Base_type & ))
211	FunctionType * baseDtor = new FunctionType();
212	baseDtor->params.push_back( new ReferenceType( new StructInstType( *virtualDtor ) ) );
213
214	// Generates:
215	// __CFA_set_virt_dtor( this, (void (*)( Base_type & ))__my_dtor )
216	setDtorBody->push_back( new ExprStmt(
217	decl->location,
218	new UntypedExpr (
219	decl->location,
220	new NameExpr( decl->location, "__CFA_set_virt_dtor" ),
221	{
222	new NameExpr( decl->location, "this" ),
223	new CastExpr( decl->location, new NameExpr( decl->location, "__my_dtor" ), new PointerType( baseDtor ), ExplicitCast )
224	}
225	)
226	));
227
228	// Generates:
229	// __CFA_set_virt_start( (void *)(&this) );
230	setDtorBody->push_back( new ExprStmt(
231	decl->location,
232	new UntypedExpr (
233	decl->location,
234	new NameExpr( decl->location, "__CFA_set_virt_start" ),
235	{
236	new NameExpr( decl->location, "this" ),
237	new CastExpr(
238	decl->location,
239	new AddressExpr( decl->location, new NameExpr( decl->location, "this" )),
240	new PointerType( new ast::VoidType() ), ExplicitCast
241	)
242	}
243	)
244	));
245
246	// put it all together into the complete function decl from above
247	FunctionDecl * setDtorFunction = new FunctionDecl(
248	decl->location,
249	"__CFA_set_dtor",
250	{
251	new ObjectDecl(
252	decl->location,
253	"this",
254	ast::deepCopy( ref )
255	),
256	}, // params
257	{},
258	nullptr, // body
259	{ Storage::Static }, // storage
260	Linkage::Cforall, // linkage
261	{}, // attributes
262	{ Function::Inline }
263	);
264
265	declsToAddBefore.push_back( ast::deepCopy( setDtorFunction ) );
266
267	setDtorFunction->stmts = setDtorBody;
268
269	// The following generates the following specialized delete routine:
270	// static inline void delete( derived_type * ptr ) {
271	// if ( ptr )
272	// ^(*ptr){};
273	// __CFA_virt_free( *ptr );
274	// }
275	CompoundStmt * deleteFnBody = new CompoundStmt( decl->location );
276
277	// Generates:
278	// if ( ptr )
279	// ^(*ptr){};
280	deleteFnBody->push_back(
281	new IfStmt(
282	decl->location,
283	UntypedExpr::createCall(
284	decl->location,
285	"?!=?",
286	{
287	new NameExpr( decl->location, "ptr" ),
288	ConstantExpr::null( decl->location, new PointerType( ast::deepCopy( instType ) ) )
289	}
290	),
291	new ExprStmt(
292	decl->location,
293	UntypedExpr::createCall(
294	decl->location,
295	"^?{}",
296	{
297	UntypedExpr::createDeref( decl->location, new NameExpr( decl->location, "ptr" ))
298	}
299	)
300	)
301	)
302	);
303
304	// Generates:
305	// __CFA_virt_free( *ptr );
306	deleteFnBody->push_back( new ExprStmt(
307	decl->location,
308	UntypedExpr::createCall(
309	decl->location,
310	"__CFA_virt_free",
311	{
312	UntypedExpr::createDeref( decl->location, new NameExpr( decl->location, "ptr" ))
313	}
314	)
315	)
316	);
317
318	FunctionDecl * deleteFn = new FunctionDecl(
319	decl->location,
320	"delete",
321	{
322	new ObjectDecl(
323	decl->location,
324	"ptr",
325	new PointerType( ast::deepCopy( instType ) )
326	),
327	}, // params
328	{},
329	nullptr, // body
330	{ Storage::Static }, // storage
331	Linkage::Cforall, // linkage
332	{}, // attributes
333	{ Function::Inline }
334	);
335
336	declsToAddBefore.push_back( ast::deepCopy( deleteFn ) );
337
338	deleteFn->stmts = deleteFnBody;
339
340	torDecls.addLater( structIter->first, setDtorFunction, deleteFn );
341	}
342
343	public:
344	GenFuncsCreateTables( unordered_map<const StructDecl , CtorDtor> & structDecls, CtorDtorTable & torDecls, const StructDecl * virtualDtor ):
345	structDecls(structDecls), torDecls(torDecls), virtualDtor(virtualDtor) {}
346	};
347
348
349	// generates the trailing definitions of dtor setting routines for virtual dtors on messages and actors
350	// generates the function defns of __CFA_set_dtor
351	// separate pass is needed since __CFA_set_dtor needs to be defined after
352	// the last dtor defn which is found in prior pass
353	struct GenSetDtor : public ast::WithDeclsToAdd<> {
354	unordered_map<const StructDecl *, CtorDtor> & structDecls; // set of decls that inherit from virt dtor
355	CtorDtorTable & torDecls;
356
357	// handles adding the declaration of the dtor init routine after the last dtor detected
358	void postvisit( const FunctionDecl * decl ) {
359	if ( decl->name != "^?{}" \|\| !decl->stmts \|\| decl->params.size() != 1 ) return;
360
361	// the one param should be a reference
362	const ReferenceType * ref = dynamic_cast<const ReferenceType *>(decl->params.at(0)->get_type());
363	if ( !ref ) return;
364
365	// the reference should be to a struct instance
366	const StructInstType * instType = dynamic_cast<const StructInstType *>(ref->base.get());
367	if ( !instType ) return;
368
369	FunctionDecl * deleteRtn;
370
371	// returns nullptr if not in table
372	FunctionDecl * maybeAdd = torDecls.getToAddLater( instType->aggr(), mutate( decl ), &deleteRtn );
373	if ( maybeAdd ) {
374	declsToAddAfter.push_back( maybeAdd );
375	declsToAddAfter.push_back( deleteRtn );
376	}
377	}
378
379	public:
380	GenSetDtor( unordered_map<const StructDecl *, CtorDtor> & structDecls, CtorDtorTable & torDecls ):
381	structDecls(structDecls), torDecls(torDecls) {}
382	};
383
384	void implementVirtDtors( TranslationUnit & translationUnit ) {
385	// unordered_map to collect all derived types and associated data
386	unordered_map<const StructDecl *, CtorDtor> structDecls;
387	CtorDtorTable torDecls( structDecls );
388
389	const StructDecl * virtualDtorPtr = nullptr;
390	const StructDecl ** virtualDtor = &virtualDtorPtr;
391
392	// first pass collects all structs that inherit from virtual_dtor
393	Pass<CollectStructDecls>::run( translationUnit, structDecls, virtualDtor );
394
395	// second pass locates all dtor/ctor routines that need modifying or need fns inserted before/after
396	Pass<GenFuncsCreateTables>::run( translationUnit, structDecls, torDecls, virtualDtor );
397
398	// The third pass adds the forward decls needed to resolve circular defn problems
399	Pass<GenSetDtor>::run( translationUnit, structDecls, torDecls );
400	}
401
402	} // namespace Virtual
403
404	// Local Variables: //
405	// tab-width: 4 //
406	// mode: c++ //
407	// compile-command: "make install" //
408	// End: //
409

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