source: src/Tuples/TupleExpansion.cc@ c65a80b

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 c65a80b was 03321e4, checked in by Thierry Delisle <tdelisle@…>, 8 years ago

Fixed headers for tuples folder
  • Property mode set to 100644
File size: 14.9 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// TupleAssignment.cc --
8//
9// Author : Rodolfo G. Esteves
10// Created On : Mon May 18 07:44:20 2015
11// Last Modified By : Peter A. Buhr
12// Last Modified On : Wed Jun 21 17:35:04 2017
13// Update Count : 19
14//
15
16#include <stddef.h> // for size_t
17#include <cassert> // for assert
18#include <list> // for list
19
20#include "Common/PassVisitor.h" // for PassVisitor, WithDeclsToAdd, WithGu...
21#include "Common/ScopedMap.h" // for ScopedMap
22#include "Common/utility.h" // for CodeLocation
23#include "GenPoly/DeclMutator.h" // for DeclMutator
24#include "InitTweak/InitTweak.h" // for getFunction
25#include "Parser/LinkageSpec.h" // for Spec, C, Intrinsic
26#include "PassVisitor.h" // for mutateAll
27#include "SynTree/Constant.h" // for Constant
28#include "SynTree/Declaration.h" // for StructDecl, DeclarationWithType
29#include "SynTree/Expression.h" // for UntypedMemberExpr, Expression, Uniq...
30#include "SynTree/Label.h" // for operator==, Label
31#include "SynTree/Mutator.h" // for Mutator
32#include "SynTree/Type.h" // for Type, Type::Qualifiers, TupleType
33#include "SynTree/Visitor.h" // for Visitor
34
35class CompoundStmt;
36class TypeSubstitution;
37
38namespace Tuples {
39 namespace {
40 class MemberTupleExpander final : public Mutator {
41 public:
42 typedef Mutator Parent;
43 using Parent::mutate;
44
45 virtual Expression * mutate( UntypedMemberExpr * memberExpr ) override;
46 };
47
48 class UniqueExprExpander final : public GenPoly::DeclMutator {
49 public:
50 typedef GenPoly::DeclMutator Parent;
51 using Parent::mutate;
52
53 virtual Expression * mutate( UniqueExpr * unqExpr ) override;
54
55 std::map< int, Expression * > decls; // not vector, because order added may not be increasing order
56
57 ~UniqueExprExpander() {
58 for ( std::pair<const int, Expression *> & p : decls ) {
59 delete p.second;
60 }
61 }
62 };
63
64 class TupleAssignExpander : public Mutator {
65 public:
66 typedef Mutator Parent;
67 using Parent::mutate;
68
69 virtual Expression * mutate( TupleAssignExpr * tupleExpr );
70 };
71
72 struct TupleTypeReplacer : public WithDeclsToAdd, public WithGuards, public WithTypeSubstitution {
73 Type * postmutate( TupleType * tupleType );
74
75 void premutate( CompoundStmt * ) {
76 GuardScope( typeMap );
77 }
78 private:
79 ScopedMap< int, StructDecl * > typeMap;
80 };
81
82 class TupleIndexExpander {
83 public:
84 Expression * postmutate( TupleIndexExpr * tupleExpr );
85 };
86
87 class TupleExprExpander final : public Mutator {
88 public:
89 typedef Mutator Parent;
90 using Parent::mutate;
91
92 virtual Expression * mutate( TupleExpr * tupleExpr ) override;
93 };
94 }
95
96 void expandMemberTuples( std::list< Declaration * > & translationUnit ) {
97 MemberTupleExpander expander;
98 mutateAll( translationUnit, expander );
99 }
100
101 void expandUniqueExpr( std::list< Declaration * > & translationUnit ) {
102 UniqueExprExpander unqExpander;
103 unqExpander.mutateDeclarationList( translationUnit );
104 }
105
106 void expandTuples( std::list< Declaration * > & translationUnit ) {
107 TupleAssignExpander assnExpander;
108 mutateAll( translationUnit, assnExpander );
109
110 PassVisitor<TupleTypeReplacer> replacer;
111 mutateAll( translationUnit, replacer );
112
113 PassVisitor<TupleIndexExpander> idxExpander;
114 mutateAll( translationUnit, idxExpander );
115
116 TupleExprExpander exprExpander;
117 mutateAll( translationUnit, exprExpander );
118 }
119
120 namespace {
121 /// given a expression representing the member and an expression representing the aggregate,
122 /// reconstructs a flattened UntypedMemberExpr with the right precedence
123 Expression * reconstructMemberExpr( Expression * member, Expression * aggr, CodeLocation & loc ) {
124 if ( UntypedMemberExpr * memberExpr = dynamic_cast< UntypedMemberExpr * >( member ) ) {
125 // construct a new UntypedMemberExpr with the correct structure , and recursively
126 // expand that member expression.
127 MemberTupleExpander expander;
128 UntypedMemberExpr * inner = new UntypedMemberExpr( memberExpr->get_aggregate(), aggr->clone() );
129 UntypedMemberExpr * newMemberExpr = new UntypedMemberExpr( memberExpr->get_member(), inner );
130 inner->location = newMemberExpr->location = loc;
131 memberExpr->set_member(nullptr);
132 memberExpr->set_aggregate(nullptr);
133 delete memberExpr;
134 return newMemberExpr->acceptMutator( expander );
135 } else {
136 // not a member expression, so there is nothing to do but attach and return
137 UntypedMemberExpr * newMemberExpr = new UntypedMemberExpr( member, aggr->clone() );
138 newMemberExpr->location = loc;
139 return newMemberExpr;
140 }
141 }
142 }
143
144 Expression * MemberTupleExpander::mutate( UntypedMemberExpr * memberExpr ) {
145 if ( UntypedTupleExpr * tupleExpr = dynamic_cast< UntypedTupleExpr * > ( memberExpr->get_member() ) ) {
146 Expression * aggr = memberExpr->get_aggregate()->clone()->acceptMutator( *this );
147 // aggregate expressions which might be impure must be wrapped in unique expressions
148 // xxx - if there's a member-tuple expression nested in the aggregate, this currently generates the wrong code if a UniqueExpr is not used, and it's purely an optimization to remove the UniqueExpr
149 // if ( Tuples::maybeImpure( memberExpr->get_aggregate() ) ) aggr = new UniqueExpr( aggr );
150 aggr = new UniqueExpr( aggr );
151 for ( Expression *& expr : tupleExpr->get_exprs() ) {
152 expr = reconstructMemberExpr( expr, aggr, memberExpr->location );
153 expr->location = memberExpr->location;
154 }
155 delete aggr;
156 tupleExpr->location = memberExpr->location;
157 return tupleExpr;
158 } else {
159 // there may be a tuple expr buried in the aggregate
160 // xxx - this is a memory leak
161 UntypedMemberExpr * newMemberExpr = new UntypedMemberExpr( memberExpr->get_member()->clone(), memberExpr->get_aggregate()->acceptMutator( *this ) );
162 newMemberExpr->location = memberExpr->location;
163 return newMemberExpr;
164 }
165 }
166
167 Expression * UniqueExprExpander::mutate( UniqueExpr * unqExpr ) {
168 unqExpr = safe_dynamic_cast< UniqueExpr * > ( Parent::mutate( unqExpr ) );
169 const int id = unqExpr->get_id();
170
171 // on first time visiting a unique expr with a particular ID, generate the expression that replaces all UniqueExprs with that ID,
172 // and lookup on subsequent hits. This ensures that all unique exprs with the same ID reference the same variable.
173 if ( ! decls.count( id ) ) {
174 Expression * assignUnq;
175 Expression * var = unqExpr->get_var();
176 if ( unqExpr->get_object() ) {
177 // an object was generated to represent this unique expression -- it should be added to the list of declarations now
178 addDeclaration( unqExpr->get_object() );
179 unqExpr->set_object( nullptr );
180 // steal the expr from the unqExpr
181 assignUnq = UntypedExpr::createAssign( unqExpr->get_var()->clone(), unqExpr->get_expr() );
182 unqExpr->set_expr( nullptr );
183 } else {
184 // steal the already generated assignment to var from the unqExpr - this has been generated by FixInit
185 Expression * expr = unqExpr->get_expr();
186 CommaExpr * commaExpr = safe_dynamic_cast< CommaExpr * >( expr );
187 assignUnq = commaExpr->get_arg1();
188 commaExpr->set_arg1( nullptr );
189 }
190 ObjectDecl * finished = new ObjectDecl( toString( "_unq", id, "_finished_" ), Type::StorageClasses(), LinkageSpec::Cforall, nullptr, new BasicType( Type::Qualifiers(), BasicType::Bool ),
191 new SingleInit( new ConstantExpr( Constant::from_int( 0 ) ) ) );
192 addDeclaration( finished );
193 // (finished ? _unq_expr_N : (_unq_expr_N = <unqExpr->get_expr()>, finished = 1, _unq_expr_N))
194 // This pattern ensures that each unique expression is evaluated once, regardless of evaluation order of the generated C code.
195 Expression * assignFinished = UntypedExpr::createAssign( new VariableExpr(finished), new ConstantExpr( Constant::from_int( 1 ) ) );
196 ConditionalExpr * condExpr = new ConditionalExpr( new VariableExpr( finished ), var->clone(),
197 new CommaExpr( new CommaExpr( assignUnq, assignFinished ), var->clone() ) );
198 condExpr->set_result( var->get_result()->clone() );
199 condExpr->set_env( maybeClone( unqExpr->get_env() ) );
200 decls[id] = condExpr;
201 }
202 delete unqExpr;
203 return decls[id]->clone();
204 }
205
206 Expression * TupleAssignExpander::mutate( TupleAssignExpr * assnExpr ) {
207 assnExpr = safe_dynamic_cast< TupleAssignExpr * >( Parent::mutate( assnExpr ) );
208 StmtExpr * ret = assnExpr->get_stmtExpr();
209 assnExpr->set_stmtExpr( nullptr );
210 // move env to StmtExpr
211 ret->set_env( assnExpr->get_env() );
212 assnExpr->set_env( nullptr );
213 delete assnExpr;
214 return ret;
215 }
216
217 Type * TupleTypeReplacer::postmutate( TupleType * tupleType ) {
218 unsigned tupleSize = tupleType->size();
219 if ( ! typeMap.count( tupleSize ) ) {
220 // generate struct type to replace tuple type based on the number of components in the tuple
221 StructDecl * decl = new StructDecl( toString( "_tuple", tupleSize, "_" ) );
222 decl->set_body( true );
223 for ( size_t i = 0; i < tupleSize; ++i ) {
224 TypeDecl * tyParam = new TypeDecl( toString( "tuple_param_", tupleSize, "_", i ), Type::StorageClasses(), nullptr, TypeDecl::Any );
225 decl->get_members().push_back( new ObjectDecl( toString("field_", i ), Type::StorageClasses(), LinkageSpec::C, nullptr, new TypeInstType( Type::Qualifiers(), tyParam->get_name(), tyParam ), nullptr ) );
226 decl->get_parameters().push_back( tyParam );
227 }
228 if ( tupleSize == 0 ) {
229 // empty structs are not standard C. Add a dummy field to empty tuples to silence warnings when a compound literal Tuple0 is created.
230 decl->get_members().push_back( new ObjectDecl( "dummy", Type::StorageClasses(), LinkageSpec::C, nullptr, new BasicType( Type::Qualifiers(), BasicType::SignedInt ), nullptr ) );
231 }
232 typeMap[tupleSize] = decl;
233 declsToAddBefore.push_back( decl );
234 }
235 Type::Qualifiers qualifiers = tupleType->get_qualifiers();
236
237 StructDecl * decl = typeMap[tupleSize];
238 StructInstType * newType = new StructInstType( qualifiers, decl );
239 for ( auto p : group_iterate( tupleType->get_types(), decl->get_parameters() ) ) {
240 Type * t = std::get<0>(p);
241 TypeDecl * td = std::get<1>(p);
242 newType->get_parameters().push_back( new TypeExpr( t->clone() ) );
243 if ( env ) {
244 // add bindings to the type environment.
245 // xxx - This may not be sufficient, it may be necessary to rename type variables on StructInstType?
246 env->add( td->get_name(), t->clone() );
247 }
248 }
249 delete tupleType;
250 return newType;
251 }
252
253 Expression * TupleIndexExpander::postmutate( TupleIndexExpr * tupleExpr ) {
254 Expression * tuple = tupleExpr->get_tuple();
255 assert( tuple );
256 tupleExpr->set_tuple( nullptr );
257 unsigned int idx = tupleExpr->get_index();
258 TypeSubstitution * env = tupleExpr->get_env();
259 tupleExpr->set_env( nullptr );
260 delete tupleExpr;
261
262 StructInstType * type = safe_dynamic_cast< StructInstType * >( tuple->get_result() );
263 StructDecl * structDecl = type->get_baseStruct();
264 assert( structDecl->get_members().size() > idx );
265 Declaration * member = *std::next(structDecl->get_members().begin(), idx);
266 MemberExpr * memExpr = new MemberExpr( safe_dynamic_cast< DeclarationWithType * >( member ), tuple );
267 memExpr->set_env( env );
268 return memExpr;
269 }
270
271 Expression * replaceTupleExpr( Type * result, const std::list< Expression * > & exprs, TypeSubstitution * env ) {
272 if ( result->isVoid() ) {
273 // void result - don't need to produce a value for cascading - just output a chain of comma exprs
274 assert( ! exprs.empty() );
275 std::list< Expression * >::const_iterator iter = exprs.begin();
276 Expression * expr = new CastExpr( *iter++ );
277 for ( ; iter != exprs.end(); ++iter ) {
278 expr = new CommaExpr( expr, new CastExpr( *iter ) );
279 }
280 expr->set_env( env );
281 return expr;
282 } else {
283 // typed tuple expression - produce a compound literal which performs each of the expressions
284 // as a distinct part of its initializer - the produced compound literal may be used as part of
285 // another expression
286 std::list< Initializer * > inits;
287 for ( Expression * expr : exprs ) {
288 inits.push_back( new SingleInit( expr ) );
289 }
290 Expression * expr = new CompoundLiteralExpr( result, new ListInit( inits ) );
291 expr->set_env( env );
292 return expr;
293 }
294 }
295
296 Expression * TupleExprExpander::mutate( TupleExpr * tupleExpr ) {
297 // recursively expand sub-tuple-expressions
298 tupleExpr = safe_dynamic_cast<TupleExpr *>(Parent::mutate(tupleExpr));
299 Type * result = tupleExpr->get_result();
300 std::list< Expression * > exprs = tupleExpr->get_exprs();
301 assert( result );
302 TypeSubstitution * env = tupleExpr->get_env();
303
304 // remove data from shell and delete it
305 tupleExpr->set_result( nullptr );
306 tupleExpr->get_exprs().clear();
307 tupleExpr->set_env( nullptr );
308 delete tupleExpr;
309
310 return replaceTupleExpr( result, exprs, env );
311 }
312
313 Type * makeTupleType( const std::list< Expression * > & exprs ) {
314 // produce the TupleType which aggregates the types of the exprs
315 std::list< Type * > types;
316 Type::Qualifiers qualifiers( Type::Const | Type::Volatile | Type::Restrict | Type::Lvalue | Type::Atomic | Type::Mutex );
317 for ( Expression * expr : exprs ) {
318 assert( expr->get_result() );
319 if ( expr->get_result()->isVoid() ) {
320 // if the type of any expr is void, the type of the entire tuple is void
321 return new VoidType( Type::Qualifiers() );
322 }
323 Type * type = expr->get_result()->clone();
324 types.push_back( type );
325 // the qualifiers on the tuple type are the qualifiers that exist on all component types
326 qualifiers &= type->get_qualifiers();
327 } // for
328 if ( exprs.empty() ) qualifiers = Type::Qualifiers();
329 return new TupleType( qualifiers, types );
330 }
331
332 TypeInstType * isTtype( Type * type ) {
333 if ( TypeInstType * inst = dynamic_cast< TypeInstType * >( type ) ) {
334 if ( inst->get_baseType() && inst->get_baseType()->get_kind() == TypeDecl::Ttype ) {
335 return inst;
336 }
337 }
338 return nullptr;
339 }
340
341 namespace {
342 /// determines if impurity (read: side-effects) may exist in a piece of code. Currently gives a very crude approximation, wherein any function call expression means the code may be impure
343 class ImpurityDetector : public Visitor {
344 public:
345 typedef Visitor Parent;
346 virtual void visit( ApplicationExpr * appExpr ) {
347 if ( DeclarationWithType * function = InitTweak::getFunction( appExpr ) ) {
348 if ( function->get_linkage() == LinkageSpec::Intrinsic ) {
349 if ( function->get_name() == "*?" || function->get_name() == "?[?]" ) {
350 // intrinsic dereference, subscript are pure, but need to recursively look for impurity
351 Parent::visit( appExpr );
352 return;
353 }
354 }
355 }
356 maybeImpure = true;
357 }
358 virtual void visit( __attribute__((unused)) UntypedExpr * untypedExpr ) { maybeImpure = true; }
359 bool maybeImpure = false;
360 };
361 } // namespace
362
363 bool maybeImpure( Expression * expr ) {
364 ImpurityDetector detector;
365 expr->accept( detector );
366 return detector.maybeImpure;
367 }
368} // namespace Tuples
369
370// Local Variables: //
371// tab-width: 4 //
372// mode: c++ //
373// compile-command: "make install" //
374// End: //
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