source: src/GenPoly/Specialize.cc@ eada3cf

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 eada3cf was 8135d4c, checked in by Rob Schluntz <rschlunt@…>, 8 years ago

Merge branch 'master' into references
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File size: 16.2 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> // for assert, assertf
17#include <iterator> // for back_insert_iterator, back_i...
18#include <map> // for _Rb_tree_iterator, _Rb_tree_...
19#include <memory> // for unique_ptr
20#include <string> // for string
21#include <tuple> // for get
22#include <utility> // for pair
23
24#include "Common/SemanticError.h" // for SemanticError
25#include "Common/UniqueName.h" // for UniqueName
26#include "Common/utility.h" // for group_iterate
27#include "GenPoly.h" // for getFunctionType
28#include "InitTweak/InitTweak.h" // for isIntrinsicCallExpr
29#include "Parser/LinkageSpec.h" // for C
30#include "PolyMutator.h" // for PolyMutator
31#include "ResolvExpr/FindOpenVars.h" // for findOpenVars
32#include "ResolvExpr/TypeEnvironment.h" // for OpenVarSet, AssertionSet
33#include "Specialize.h"
34#include "SynTree/Attribute.h" // for Attribute
35#include "SynTree/Declaration.h" // for FunctionDecl, DeclarationWit...
36#include "SynTree/Expression.h" // for ApplicationExpr, Expression
37#include "SynTree/Label.h" // for Label, noLabels
38#include "SynTree/Mutator.h" // for mutateAll
39#include "SynTree/Statement.h" // for CompoundStmt, DeclStmt, Expr...
40#include "SynTree/Type.h" // for FunctionType, TupleType, Type
41#include "SynTree/TypeSubstitution.h" // for TypeSubstitution
42#include "SynTree/Visitor.h" // for Visitor
43
44namespace GenPoly {
45 class Specialize final : public PolyMutator {
46 public:
47 using PolyMutator::mutate;
48 virtual Expression * mutate( ApplicationExpr *applicationExpr ) override;
49 virtual Expression * mutate( AddressExpr *castExpr ) override;
50 virtual Expression * mutate( CastExpr *castExpr ) override;
51 // virtual Expression * mutate( LogicalExpr *logicalExpr );
52 // virtual Expression * mutate( ConditionalExpr *conditionalExpr );
53 // virtual Expression * mutate( CommaExpr *commaExpr );
54
55 void handleExplicitParams( ApplicationExpr *appExpr );
56 Expression * createThunkFunction( FunctionType *funType, Expression *actual, InferredParams *inferParams );
57 Expression * doSpecialization( Type *formalType, Expression *actual, InferredParams *inferParams = nullptr );
58
59 std::string paramPrefix = "_p";
60 };
61
62 /// Looks up open variables in actual type, returning true if any of them are bound in the environment or formal type.
63 bool needsPolySpecialization( Type *formalType, Type *actualType, TypeSubstitution *env ) {
64 if ( env ) {
65 using namespace ResolvExpr;
66 OpenVarSet openVars, closedVars;
67 AssertionSet need, have;
68 findOpenVars( formalType, openVars, closedVars, need, have, false );
69 findOpenVars( actualType, openVars, closedVars, need, have, true );
70 for ( OpenVarSet::const_iterator openVar = openVars.begin(); openVar != openVars.end(); ++openVar ) {
71 Type *boundType = env->lookup( openVar->first );
72 if ( ! boundType ) continue;
73 if ( TypeInstType *typeInst = dynamic_cast< TypeInstType* >( boundType ) ) {
74 if ( closedVars.find( typeInst->get_name() ) == closedVars.end() ) {
75 return true;
76 } // if
77 } else {
78 return true;
79 } // if
80 } // for
81 return false;
82 } else {
83 return false;
84 } // if
85 }
86
87 /// True if both types have the same structure, but not necessarily the same types.
88 /// That is, either both types are tuple types with the same size (recursively), or
89 /// both are not tuple types.
90 bool matchingTupleStructure( Type * t1, Type * t2 ) {
91 TupleType * tuple1 = dynamic_cast< TupleType * >( t1 );
92 TupleType * tuple2 = dynamic_cast< TupleType * >( t2 );
93 if ( tuple1 && tuple2 ) {
94 if ( tuple1->size() != tuple2->size() ) return false;
95 for ( auto types : group_iterate( tuple1->get_types(), tuple2->get_types() ) ) {
96 if ( ! matchingTupleStructure( std::get<0>( types ), std::get<1>( types ) ) ) return false;
97 }
98 return true;
99 } else if ( ! tuple1 && ! tuple2 ) return true;
100 return false;
101 }
102
103 // walk into tuple type and find the number of components
104 size_t singleParameterSize( Type * type ) {
105 if ( TupleType * tt = dynamic_cast< TupleType * >( type ) ) {
106 size_t sz = 0;
107 for ( Type * t : *tt ) {
108 sz += singleParameterSize( t );
109 }
110 return sz;
111 } else {
112 return 1;
113 }
114 }
115
116 // find the total number of components in a parameter list
117 size_t functionParameterSize( FunctionType * ftype ) {
118 size_t sz = 0;
119 for ( DeclarationWithType * p : ftype->get_parameters() ) {
120 sz += singleParameterSize( p->get_type() );
121 }
122 return sz;
123 }
124
125 bool needsTupleSpecialization( Type *formalType, Type *actualType ) {
126 // Needs tuple specialization if the structure of the formal type and actual type do not match.
127 // This is the case if the formal type has ttype polymorphism, or if the structure of tuple types
128 // between the function do not match exactly.
129 if ( FunctionType * fftype = getFunctionType( formalType ) ) {
130 if ( fftype->isTtype() ) return true;
131 // conversion of 0 (null) to function type does not require tuple specialization
132 if ( dynamic_cast< ZeroType * >( actualType ) ) return false;
133 FunctionType * aftype = getFunctionType( actualType->stripReferences() );
134 assertf( aftype, "formal type is a function type, but actual type is not: %s", toString( actualType ).c_str() );
135 // Can't tuple specialize if parameter sizes deeply-differ.
136 if ( functionParameterSize( fftype ) != functionParameterSize( aftype ) ) return false;
137 // tuple-parameter sizes are the same, but actual parameter sizes differ - must tuple specialize
138 if ( fftype->get_parameters().size() != aftype->get_parameters().size() ) return true;
139 // total parameter size can be the same, while individual parameters can have different structure
140 for ( auto params : group_iterate( fftype->get_parameters(), aftype->get_parameters() ) ) {
141 DeclarationWithType * formal = std::get<0>(params);
142 DeclarationWithType * actual = std::get<1>(params);
143 if ( ! matchingTupleStructure( formal->get_type(), actual->get_type() ) ) return true;
144 }
145 }
146 return false;
147 }
148
149 bool needsSpecialization( Type *formalType, Type *actualType, TypeSubstitution *env ) {
150 return needsPolySpecialization( formalType, actualType, env ) || needsTupleSpecialization( formalType, actualType );
151 }
152
153 Expression * Specialize::doSpecialization( Type *formalType, Expression *actual, InferredParams *inferParams ) {
154 assertf( actual->has_result(), "attempting to specialize an untyped expression" );
155 if ( needsSpecialization( formalType, actual->get_result(), env ) ) {
156 if ( FunctionType *funType = getFunctionType( formalType ) ) {
157 ApplicationExpr *appExpr;
158 VariableExpr *varExpr;
159 if ( ( appExpr = dynamic_cast<ApplicationExpr*>( actual ) ) ) {
160 return createThunkFunction( funType, appExpr->get_function(), inferParams );
161 } else if ( ( varExpr = dynamic_cast<VariableExpr*>( actual ) ) ) {
162 return createThunkFunction( funType, varExpr, inferParams );
163 } else {
164 // This likely won't work, as anything that could build an ApplicationExpr probably hit one of the previous two branches
165 return createThunkFunction( funType, actual, inferParams );
166 }
167 } else {
168 return actual;
169 } // if
170 } else {
171 return actual;
172 } // if
173 }
174
175 /// restructures the arguments to match the structure of the formal parameters of the actual function.
176 /// [begin, end) are the exploded arguments.
177 template< typename Iterator, typename OutIterator >
178 void structureArg( Type * type, Iterator & begin, Iterator end, OutIterator out ) {
179 if ( TupleType * tuple = dynamic_cast< TupleType * >( type ) ) {
180 std::list< Expression * > exprs;
181 for ( Type * t : *tuple ) {
182 structureArg( t, begin, end, back_inserter( exprs ) );
183 }
184 *out++ = new TupleExpr( exprs );
185 } else {
186 assertf( begin != end, "reached the end of the arguments while structuring" );
187 *out++ = *begin++;
188 }
189 }
190
191 /// explode assuming simple cases: either type is pure tuple (but not tuple expr) or type is non-tuple.
192 template< typename OutputIterator >
193 void explodeSimple( Expression * expr, OutputIterator out ) {
194 if ( TupleType * tupleType = dynamic_cast< TupleType * > ( expr->get_result() ) ) {
195 // tuple type, recursively index into its components
196 for ( unsigned int i = 0; i < tupleType->size(); i++ ) {
197 explodeSimple( new TupleIndexExpr( expr->clone(), i ), out );
198 }
199 delete expr;
200 } else {
201 // non-tuple type - output a clone of the expression
202 *out++ = expr;
203 }
204 }
205
206 struct EnvTrimmer : public Visitor {
207 TypeSubstitution * env, * newEnv;
208 EnvTrimmer( TypeSubstitution * env, TypeSubstitution * newEnv ) : env( env ), newEnv( newEnv ){}
209 virtual void visit( TypeDecl * tyDecl ) {
210 // transfer known bindings for seen type variables
211 if ( Type * t = env->lookup( tyDecl->get_name() ) ) {
212 newEnv->add( tyDecl->get_name(), t );
213 }
214 }
215 };
216
217 /// reduce environment to just the parts that are referenced in a given expression
218 TypeSubstitution * trimEnv( ApplicationExpr * expr, TypeSubstitution * env ) {
219 if ( env ) {
220 TypeSubstitution * newEnv = new TypeSubstitution();
221 EnvTrimmer trimmer( env, newEnv );
222 expr->accept( trimmer );
223 return newEnv;
224 }
225 return nullptr;
226 }
227
228 /// Generates a thunk that calls `actual` with type `funType` and returns its address
229 Expression * Specialize::createThunkFunction( FunctionType *funType, Expression *actual, InferredParams *inferParams ) {
230 static UniqueName thunkNamer( "_thunk" );
231
232 FunctionType *newType = funType->clone();
233 if ( env ) {
234 // it is important to replace only occurrences of type variables that occur free in the
235 // thunk's type
236 env->applyFree( newType );
237 } // if
238 // create new thunk with same signature as formal type (C linkage, empty body)
239 FunctionDecl *thunkFunc = new FunctionDecl( thunkNamer.newName(), Type::StorageClasses(), LinkageSpec::C, newType, new CompoundStmt( noLabels ) );
240 thunkFunc->fixUniqueId();
241
242 // thunks may be generated and not used - silence warning with attribute
243 thunkFunc->get_attributes().push_back( new Attribute( "unused" ) );
244
245 // thread thunk parameters into call to actual function, naming thunk parameters as we go
246 UniqueName paramNamer( paramPrefix );
247 ApplicationExpr *appExpr = new ApplicationExpr( actual );
248
249 FunctionType * actualType = getFunctionType( actual->get_result() )->clone();
250 if ( env ) {
251 // need to apply the environment to the actual function's type, since it may itself be polymorphic
252 env->apply( actualType );
253 }
254 std::unique_ptr< FunctionType > actualTypeManager( actualType ); // for RAII
255 std::list< DeclarationWithType * >::iterator actualBegin = actualType->get_parameters().begin();
256 std::list< DeclarationWithType * >::iterator actualEnd = actualType->get_parameters().end();
257
258 std::list< Expression * > args;
259 for ( DeclarationWithType* param : thunkFunc->get_functionType()->get_parameters() ) {
260 // name each thunk parameter and explode it - these are then threaded back into the actual function call.
261 param->set_name( paramNamer.newName() );
262 explodeSimple( new VariableExpr( param ), back_inserter( args ) );
263 }
264
265 // walk parameters to the actual function alongside the exploded thunk parameters and restructure the arguments to match the actual parameters.
266 std::list< Expression * >::iterator argBegin = args.begin(), argEnd = args.end();
267 for ( ; actualBegin != actualEnd; ++actualBegin ) {
268 structureArg( (*actualBegin)->get_type(), argBegin, argEnd, back_inserter( appExpr->get_args() ) );
269 }
270
271 appExpr->set_env( trimEnv( appExpr, env ) );
272 if ( inferParams ) {
273 appExpr->get_inferParams() = *inferParams;
274 } // if
275
276 // handle any specializations that may still be present
277 std::string oldParamPrefix = paramPrefix;
278 paramPrefix += "p";
279 // save stmtsToAdd in oldStmts
280 std::list< Statement* > oldStmts;
281 oldStmts.splice( oldStmts.end(), stmtsToAdd );
282 mutate( appExpr );
283 paramPrefix = oldParamPrefix;
284 // write any statements added for recursive specializations into the thunk body
285 thunkFunc->get_statements()->get_kids().splice( thunkFunc->get_statements()->get_kids().end(), stmtsToAdd );
286 // restore oldStmts into stmtsToAdd
287 stmtsToAdd.splice( stmtsToAdd.end(), oldStmts );
288
289 // add return (or valueless expression) to the thunk
290 Statement *appStmt;
291 if ( funType->get_returnVals().empty() ) {
292 appStmt = new ExprStmt( noLabels, appExpr );
293 } else {
294 appStmt = new ReturnStmt( noLabels, appExpr );
295 } // if
296 thunkFunc->get_statements()->get_kids().push_back( appStmt );
297
298 // add thunk definition to queue of statements to add
299 stmtsToAdd.push_back( new DeclStmt( noLabels, thunkFunc ) );
300 // return address of thunk function as replacement expression
301 return new AddressExpr( new VariableExpr( thunkFunc ) );
302 }
303
304 void Specialize::handleExplicitParams( ApplicationExpr *appExpr ) {
305 // create thunks for the explicit parameters
306 assert( appExpr->get_function()->has_result() );
307 FunctionType *function = getFunctionType( appExpr->get_function()->get_result() );
308 assert( function );
309 std::list< DeclarationWithType* >::iterator formal;
310 std::list< Expression* >::iterator actual;
311 for ( formal = function->get_parameters().begin(), actual = appExpr->get_args().begin(); formal != function->get_parameters().end() && actual != appExpr->get_args().end(); ++formal, ++actual ) {
312 *actual = doSpecialization( (*formal )->get_type(), *actual, &appExpr->get_inferParams() );
313 }
314 }
315
316 Expression * Specialize::mutate( ApplicationExpr *appExpr ) {
317 appExpr->get_function()->acceptMutator( *this );
318 mutateAll( appExpr->get_args(), *this );
319
320 if ( ! InitTweak::isIntrinsicCallExpr( appExpr ) ) {
321 // create thunks for the inferred parameters
322 // don't need to do this for intrinsic calls, because they aren't actually passed
323 // need to handle explicit params before inferred params so that explicit params do not recieve a changed set of inferParams (and change them again)
324 // alternatively, if order starts to matter then copy appExpr's inferParams and pass them to handleExplicitParams.
325 handleExplicitParams( appExpr );
326 for ( InferredParams::iterator inferParam = appExpr->get_inferParams().begin(); inferParam != appExpr->get_inferParams().end(); ++inferParam ) {
327 inferParam->second.expr = doSpecialization( inferParam->second.formalType, inferParam->second.expr, inferParam->second.inferParams.get() );
328 }
329 }
330 return appExpr;
331 }
332
333 Expression * Specialize::mutate( AddressExpr *addrExpr ) {
334 addrExpr->get_arg()->acceptMutator( *this );
335 assert( addrExpr->has_result() );
336 addrExpr->set_arg( doSpecialization( addrExpr->get_result(), addrExpr->get_arg() ) );
337 return addrExpr;
338 }
339
340 Expression * Specialize::mutate( CastExpr *castExpr ) {
341 castExpr->get_arg()->acceptMutator( *this );
342 if ( castExpr->get_result()->isVoid() ) {
343 // can't specialize if we don't have a return value
344 return castExpr;
345 }
346 Expression *specialized = doSpecialization( castExpr->get_result(), castExpr->get_arg() );
347 if ( specialized != castExpr->get_arg() ) {
348 // assume here that the specialization incorporates the cast
349 return specialized;
350 } else {
351 return castExpr;
352 }
353 }
354
355 // Removing these for now. Richard put these in for some reason, but it's not clear why.
356 // In particular, copy constructors produce a comma expression, and with this code the parts
357 // of that comma expression are not specialized, which causes problems.
358
359 // Expression * Specialize::mutate( LogicalExpr *logicalExpr ) {
360 // return logicalExpr;
361 // }
362
363 // Expression * Specialize::mutate( ConditionalExpr *condExpr ) {
364 // return condExpr;
365 // }
366
367 // Expression * Specialize::mutate( CommaExpr *commaExpr ) {
368 // return commaExpr;
369 // }
370
371 void convertSpecializations( std::list< Declaration* >& translationUnit ) {
372 Specialize spec;
373 mutateAll( translationUnit, spec );
374 }
375} // namespace GenPoly
376
377// Local Variables: //
378// tab-width: 4 //
379// mode: c++ //
380// compile-command: "make install" //
381// End: //
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