source: src/GenPoly/Specialize.cc@ ae4038d

ADT aaron-thesis arm-eh ast-experimental cleanup-dtors 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 ae4038d was ae4038d, checked in by Rob Schluntz <rschlunt@…>, 8 years ago

Fix tuple specialize check to more precisely determine where tuple specialization is necessary [fixes #35]
  • Property mode set to 100644
File size: 15.0 KB
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1//
2// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
3//
4// The contents of this file are covered under the licence agreement in the
5// file "LICENCE" distributed with Cforall.
6//
7// Specialize.cc --
8//
9// Author : Richard C. Bilson
10// Created On : Mon May 18 07:44:20 2015
11// Last Modified By : Peter A. Buhr
12// Last Modified On : Thu Mar 16 07:53:59 2017
13// Update Count : 31
14//
15
16#include <cassert>
17
18#include "Specialize.h"
19#include "GenPoly.h"
20#include "PolyMutator.h"
21
22#include "Parser/ParseNode.h"
23
24#include "SynTree/Expression.h"
25#include "SynTree/Statement.h"
26#include "SynTree/Type.h"
27#include "SynTree/Attribute.h"
28#include "SynTree/TypeSubstitution.h"
29#include "SynTree/Mutator.h"
30#include "ResolvExpr/FindOpenVars.h"
31#include "Common/UniqueName.h"
32#include "Common/utility.h"
33#include "InitTweak/InitTweak.h"
34#include "Tuples/Tuples.h"
35
36namespace GenPoly {
37 class Specialize final : public PolyMutator {
38 public:
39 using PolyMutator::mutate;
40 virtual Expression * mutate( ApplicationExpr *applicationExpr ) override;
41 virtual Expression * mutate( AddressExpr *castExpr ) override;
42 virtual Expression * mutate( CastExpr *castExpr ) override;
43 // virtual Expression * mutate( LogicalExpr *logicalExpr );
44 // virtual Expression * mutate( ConditionalExpr *conditionalExpr );
45 // virtual Expression * mutate( CommaExpr *commaExpr );
46
47 void handleExplicitParams( ApplicationExpr *appExpr );
48 Expression * createThunkFunction( FunctionType *funType, Expression *actual, InferredParams *inferParams );
49 Expression * doSpecialization( Type *formalType, Expression *actual, InferredParams *inferParams = nullptr );
50
51 std::string paramPrefix = "_p";
52 };
53
54 /// Looks up open variables in actual type, returning true if any of them are bound in the environment or formal type.
55 bool needsPolySpecialization( Type *formalType, Type *actualType, TypeSubstitution *env ) {
56 if ( env ) {
57 using namespace ResolvExpr;
58 OpenVarSet openVars, closedVars;
59 AssertionSet need, have;
60 findOpenVars( formalType, openVars, closedVars, need, have, false );
61 findOpenVars( actualType, openVars, closedVars, need, have, true );
62 for ( OpenVarSet::const_iterator openVar = openVars.begin(); openVar != openVars.end(); ++openVar ) {
63 Type *boundType = env->lookup( openVar->first );
64 if ( ! boundType ) continue;
65 if ( TypeInstType *typeInst = dynamic_cast< TypeInstType* >( boundType ) ) {
66 if ( closedVars.find( typeInst->get_name() ) == closedVars.end() ) {
67 return true;
68 } // if
69 } else {
70 return true;
71 } // if
72 } // for
73 return false;
74 } else {
75 return false;
76 } // if
77 }
78
79 /// True if both types have the same structure, but not necessarily the same types.
80 /// That is, either both types are tuple types with the same size (recursively), or
81 /// both are not tuple types.
82 bool matchingTupleStructure( Type * t1, Type * t2 ) {
83 TupleType * tuple1 = dynamic_cast< TupleType * >( t1 );
84 TupleType * tuple2 = dynamic_cast< TupleType * >( t2 );
85 if ( tuple1 && tuple2 ) {
86 if ( tuple1->size() != tuple2->size() ) return false;
87 for ( auto types : group_iterate( tuple1->get_types(), tuple2->get_types() ) ) {
88 if ( ! matchingTupleStructure( std::get<0>( types ), std::get<1>( types ) ) ) return false;
89 }
90 return true;
91 } else if ( ! tuple1 && ! tuple2 ) return true;
92 return false;
93 }
94
95 // walk into tuple type and find the number of components
96 size_t singleParameterSize( Type * type ) {
97 if ( TupleType * tt = dynamic_cast< TupleType * >( type ) ) {
98 size_t sz = 0;
99 for ( Type * t : *tt ) {
100 sz += singleParameterSize( t );
101 }
102 return sz;
103 } else {
104 return 1;
105 }
106 }
107
108 // find the total number of components in a parameter list
109 size_t functionParameterSize( FunctionType * ftype ) {
110 size_t sz = 0;
111 for ( DeclarationWithType * p : ftype->get_parameters() ) {
112 sz += singleParameterSize( p->get_type() );
113 }
114 return sz;
115 }
116
117 bool needsTupleSpecialization( Type *formalType, Type *actualType ) {
118 // Needs tuple specialization if the structure of the formal type and actual type do not match.
119 // This is the case if the formal type has ttype polymorphism, or if the structure of tuple types
120 // between the function do not match exactly.
121 if ( FunctionType * fftype = getFunctionType( formalType ) ) {
122 if ( fftype->isTtype() ) return true;
123 // conversion of 0 (null) to function type does not require tuple specialization
124 if ( dynamic_cast< ZeroType * >( actualType ) ) return false;
125 FunctionType * aftype = getFunctionType( actualType );
126 assertf( aftype, "formal type is a function type, but actual type is not." );
127 // Can't tuple specialize if parameter sizes deeply-differ.
128 if ( functionParameterSize( fftype ) != functionParameterSize( aftype ) ) return false;
129 // tuple-parameter sizes are the same, but actual parameter sizes differ - must tuple specialize
130 if ( fftype->get_parameters().size() != aftype->get_parameters().size() ) return true;
131 // total parameter size can be the same, while individual parameters can have different structure
132 for ( auto params : group_iterate( fftype->get_parameters(), aftype->get_parameters() ) ) {
133 DeclarationWithType * formal = std::get<0>(params);
134 DeclarationWithType * actual = std::get<1>(params);
135 if ( ! matchingTupleStructure( formal->get_type(), actual->get_type() ) ) return true;
136 }
137 }
138 return false;
139 }
140
141 bool needsSpecialization( Type *formalType, Type *actualType, TypeSubstitution *env ) {
142 return needsPolySpecialization( formalType, actualType, env ) || needsTupleSpecialization( formalType, actualType );
143 }
144
145 Expression * Specialize::doSpecialization( Type *formalType, Expression *actual, InferredParams *inferParams ) {
146 assertf( actual->has_result(), "attempting to specialize an untyped expression" );
147 if ( needsSpecialization( formalType, actual->get_result(), env ) ) {
148 if ( FunctionType *funType = getFunctionType( formalType ) ) {
149 ApplicationExpr *appExpr;
150 VariableExpr *varExpr;
151 if ( ( appExpr = dynamic_cast<ApplicationExpr*>( actual ) ) ) {
152 return createThunkFunction( funType, appExpr->get_function(), inferParams );
153 } else if ( ( varExpr = dynamic_cast<VariableExpr*>( actual ) ) ) {
154 return createThunkFunction( funType, varExpr, inferParams );
155 } else {
156 // This likely won't work, as anything that could build an ApplicationExpr probably hit one of the previous two branches
157 return createThunkFunction( funType, actual, inferParams );
158 }
159 } else {
160 return actual;
161 } // if
162 } else {
163 return actual;
164 } // if
165 }
166
167 /// restructures the arguments to match the structure of the formal parameters of the actual function.
168 /// [begin, end) are the exploded arguments.
169 template< typename Iterator, typename OutIterator >
170 void structureArg( Type * type, Iterator & begin, Iterator end, OutIterator out ) {
171 if ( TupleType * tuple = dynamic_cast< TupleType * >( type ) ) {
172 std::list< Expression * > exprs;
173 for ( Type * t : *tuple ) {
174 structureArg( t, begin, end, back_inserter( exprs ) );
175 }
176 *out++ = new TupleExpr( exprs );
177 } else {
178 assertf( begin != end, "reached the end of the arguments while structuring" );
179 *out++ = *begin++;
180 }
181 }
182
183 /// explode assuming simple cases: either type is pure tuple (but not tuple expr) or type is non-tuple.
184 template< typename OutputIterator >
185 void explodeSimple( Expression * expr, OutputIterator out ) {
186 if ( TupleType * tupleType = dynamic_cast< TupleType * > ( expr->get_result() ) ) {
187 // tuple type, recursively index into its components
188 for ( unsigned int i = 0; i < tupleType->size(); i++ ) {
189 explodeSimple( new TupleIndexExpr( expr->clone(), i ), out );
190 }
191 delete expr;
192 } else {
193 // non-tuple type - output a clone of the expression
194 *out++ = expr;
195 }
196 }
197
198 struct EnvTrimmer : public Visitor {
199 TypeSubstitution * env, * newEnv;
200 EnvTrimmer( TypeSubstitution * env, TypeSubstitution * newEnv ) : env( env ), newEnv( newEnv ){}
201 virtual void visit( TypeDecl * tyDecl ) {
202 // transfer known bindings for seen type variables
203 if ( Type * t = env->lookup( tyDecl->get_name() ) ) {
204 newEnv->add( tyDecl->get_name(), t );
205 }
206 }
207 };
208
209 /// reduce environment to just the parts that are referenced in a given expression
210 TypeSubstitution * trimEnv( ApplicationExpr * expr, TypeSubstitution * env ) {
211 if ( env ) {
212 TypeSubstitution * newEnv = new TypeSubstitution();
213 EnvTrimmer trimmer( env, newEnv );
214 expr->accept( trimmer );
215 return newEnv;
216 }
217 return nullptr;
218 }
219
220 /// Generates a thunk that calls `actual` with type `funType` and returns its address
221 Expression * Specialize::createThunkFunction( FunctionType *funType, Expression *actual, InferredParams *inferParams ) {
222 static UniqueName thunkNamer( "_thunk" );
223
224 FunctionType *newType = funType->clone();
225 if ( env ) {
226 // it is important to replace only occurrences of type variables that occur free in the
227 // thunk's type
228 env->applyFree( newType );
229 } // if
230 // create new thunk with same signature as formal type (C linkage, empty body)
231 FunctionDecl *thunkFunc = new FunctionDecl( thunkNamer.newName(), Type::StorageClasses(), LinkageSpec::C, newType, new CompoundStmt( noLabels ) );
232 thunkFunc->fixUniqueId();
233
234 // thunks may be generated and not used - silence warning with attribute
235 thunkFunc->get_attributes().push_back( new Attribute( "unused" ) );
236
237 // thread thunk parameters into call to actual function, naming thunk parameters as we go
238 UniqueName paramNamer( paramPrefix );
239 ApplicationExpr *appExpr = new ApplicationExpr( actual );
240
241 FunctionType * actualType = getFunctionType( actual->get_result() )->clone();
242 if ( env ) {
243 // need to apply the environment to the actual function's type, since it may itself be polymorphic
244 env->apply( actualType );
245 }
246 std::unique_ptr< FunctionType > actualTypeManager( actualType ); // for RAII
247 std::list< DeclarationWithType * >::iterator actualBegin = actualType->get_parameters().begin();
248 std::list< DeclarationWithType * >::iterator actualEnd = actualType->get_parameters().end();
249
250 std::list< Expression * > args;
251 for ( DeclarationWithType* param : thunkFunc->get_functionType()->get_parameters() ) {
252 // name each thunk parameter and explode it - these are then threaded back into the actual function call.
253 param->set_name( paramNamer.newName() );
254 explodeSimple( new VariableExpr( param ), back_inserter( args ) );
255 }
256
257 // walk parameters to the actual function alongside the exploded thunk parameters and restructure the arguments to match the actual parameters.
258 std::list< Expression * >::iterator argBegin = args.begin(), argEnd = args.end();
259 for ( ; actualBegin != actualEnd; ++actualBegin ) {
260 structureArg( (*actualBegin)->get_type(), argBegin, argEnd, back_inserter( appExpr->get_args() ) );
261 }
262
263 appExpr->set_env( trimEnv( appExpr, env ) );
264 if ( inferParams ) {
265 appExpr->get_inferParams() = *inferParams;
266 } // if
267
268 // handle any specializations that may still be present
269 std::string oldParamPrefix = paramPrefix;
270 paramPrefix += "p";
271 // save stmtsToAdd in oldStmts
272 std::list< Statement* > oldStmts;
273 oldStmts.splice( oldStmts.end(), stmtsToAdd );
274 mutate( appExpr );
275 paramPrefix = oldParamPrefix;
276 // write any statements added for recursive specializations into the thunk body
277 thunkFunc->get_statements()->get_kids().splice( thunkFunc->get_statements()->get_kids().end(), stmtsToAdd );
278 // restore oldStmts into stmtsToAdd
279 stmtsToAdd.splice( stmtsToAdd.end(), oldStmts );
280
281 // add return (or valueless expression) to the thunk
282 Statement *appStmt;
283 if ( funType->get_returnVals().empty() ) {
284 appStmt = new ExprStmt( noLabels, appExpr );
285 } else {
286 appStmt = new ReturnStmt( noLabels, appExpr );
287 } // if
288 thunkFunc->get_statements()->get_kids().push_back( appStmt );
289
290 // add thunk definition to queue of statements to add
291 stmtsToAdd.push_back( new DeclStmt( noLabels, thunkFunc ) );
292 // return address of thunk function as replacement expression
293 return new AddressExpr( new VariableExpr( thunkFunc ) );
294 }
295
296 void Specialize::handleExplicitParams( ApplicationExpr *appExpr ) {
297 // create thunks for the explicit parameters
298 assert( appExpr->get_function()->has_result() );
299 FunctionType *function = getFunctionType( appExpr->get_function()->get_result() );
300 assert( function );
301 std::list< DeclarationWithType* >::iterator formal;
302 std::list< Expression* >::iterator actual;
303 for ( formal = function->get_parameters().begin(), actual = appExpr->get_args().begin(); formal != function->get_parameters().end() && actual != appExpr->get_args().end(); ++formal, ++actual ) {
304 *actual = doSpecialization( (*formal )->get_type(), *actual, &appExpr->get_inferParams() );
305 }
306 }
307
308 Expression * Specialize::mutate( ApplicationExpr *appExpr ) {
309 appExpr->get_function()->acceptMutator( *this );
310 mutateAll( appExpr->get_args(), *this );
311
312 if ( ! InitTweak::isIntrinsicCallExpr( appExpr ) ) {
313 // create thunks for the inferred parameters
314 // don't need to do this for intrinsic calls, because they aren't actually passed
315 // need to handle explicit params before inferred params so that explicit params do not recieve a changed set of inferParams (and change them again)
316 // alternatively, if order starts to matter then copy appExpr's inferParams and pass them to handleExplicitParams.
317 handleExplicitParams( appExpr );
318 for ( InferredParams::iterator inferParam = appExpr->get_inferParams().begin(); inferParam != appExpr->get_inferParams().end(); ++inferParam ) {
319 inferParam->second.expr = doSpecialization( inferParam->second.formalType, inferParam->second.expr, inferParam->second.inferParams.get() );
320 }
321 }
322 return appExpr;
323 }
324
325 Expression * Specialize::mutate( AddressExpr *addrExpr ) {
326 addrExpr->get_arg()->acceptMutator( *this );
327 assert( addrExpr->has_result() );
328 addrExpr->set_arg( doSpecialization( addrExpr->get_result(), addrExpr->get_arg() ) );
329 return addrExpr;
330 }
331
332 Expression * Specialize::mutate( CastExpr *castExpr ) {
333 castExpr->get_arg()->acceptMutator( *this );
334 if ( castExpr->get_result()->isVoid() ) {
335 // can't specialize if we don't have a return value
336 return castExpr;
337 }
338 Expression *specialized = doSpecialization( castExpr->get_result(), castExpr->get_arg() );
339 if ( specialized != castExpr->get_arg() ) {
340 // assume here that the specialization incorporates the cast
341 return specialized;
342 } else {
343 return castExpr;
344 }
345 }
346
347 // Removing these for now. Richard put these in for some reason, but it's not clear why.
348 // In particular, copy constructors produce a comma expression, and with this code the parts
349 // of that comma expression are not specialized, which causes problems.
350
351 // Expression * Specialize::mutate( LogicalExpr *logicalExpr ) {
352 // return logicalExpr;
353 // }
354
355 // Expression * Specialize::mutate( ConditionalExpr *condExpr ) {
356 // return condExpr;
357 // }
358
359 // Expression * Specialize::mutate( CommaExpr *commaExpr ) {
360 // return commaExpr;
361 // }
362
363 void convertSpecializations( std::list< Declaration* >& translationUnit ) {
364 Specialize spec;
365 mutateAll( translationUnit, spec );
366 }
367} // namespace GenPoly
368
369// Local Variables: //
370// tab-width: 4 //
371// mode: c++ //
372// compile-command: "make install" //
373// End: //
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