source: src/Tuples/TupleExpansion.cc@ 1ae39f6e

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 1ae39f6e was 8135d4c, checked in by Rob Schluntz <rschlunt@…>, 8 years ago

Merge branch 'master' into references
  • Property mode set to 100644
File size: 14.7 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 "SynTree/Constant.h" // for Constant
27#include "SynTree/Declaration.h" // for StructDecl, DeclarationWithType
28#include "SynTree/Expression.h" // for UntypedMemberExpr, Expression, Uniq...
29#include "SynTree/Label.h" // for operator==, Label
30#include "SynTree/Mutator.h" // for Mutator
31#include "SynTree/Type.h" // for Type, Type::Qualifiers, TupleType
32#include "SynTree/Visitor.h" // for Visitor
33
34class CompoundStmt;
35class TypeSubstitution;
36
37namespace Tuples {
38 namespace {
39 struct MemberTupleExpander final : public Mutator {
40 typedef Mutator Parent;
41 using Parent::mutate;
42
43 virtual Expression * mutate( UntypedMemberExpr * memberExpr ) override;
44 };
45
46 struct UniqueExprExpander final : public WithDeclsToAdd {
47 Expression * postmutate( UniqueExpr * unqExpr );
48
49 std::map< int, Expression * > decls; // not vector, because order added may not be increasing order
50
51 ~UniqueExprExpander() {
52 for ( std::pair<const int, Expression *> & p : decls ) {
53 delete p.second;
54 }
55 }
56 };
57
58 struct TupleAssignExpander {
59 Expression * postmutate( TupleAssignExpr * tupleExpr );
60 };
61
62 struct TupleTypeReplacer : public WithDeclsToAdd, public WithGuards, public WithTypeSubstitution {
63 Type * postmutate( TupleType * tupleType );
64
65 void premutate( CompoundStmt * ) {
66 GuardScope( typeMap );
67 }
68 private:
69 ScopedMap< int, StructDecl * > typeMap;
70 };
71
72 struct TupleIndexExpander {
73 Expression * postmutate( TupleIndexExpr * tupleExpr );
74 };
75
76 struct TupleExprExpander final {
77 Expression * postmutate( TupleExpr * tupleExpr );
78 };
79 }
80
81 void expandMemberTuples( std::list< Declaration * > & translationUnit ) {
82 MemberTupleExpander expander;
83 mutateAll( translationUnit, expander );
84 }
85
86 void expandUniqueExpr( std::list< Declaration * > & translationUnit ) {
87 PassVisitor<UniqueExprExpander> unqExpander;
88 mutateAll( translationUnit, unqExpander );
89 }
90
91 void expandTuples( std::list< Declaration * > & translationUnit ) {
92 PassVisitor<TupleAssignExpander> assnExpander;
93 mutateAll( translationUnit, assnExpander );
94
95 PassVisitor<TupleTypeReplacer> replacer;
96 mutateAll( translationUnit, replacer );
97
98 PassVisitor<TupleIndexExpander> idxExpander;
99 mutateAll( translationUnit, idxExpander );
100
101 PassVisitor<TupleExprExpander> exprExpander;
102 mutateAll( translationUnit, exprExpander );
103 }
104
105 namespace {
106 /// given a expression representing the member and an expression representing the aggregate,
107 /// reconstructs a flattened UntypedMemberExpr with the right precedence
108 Expression * reconstructMemberExpr( Expression * member, Expression * aggr, CodeLocation & loc ) {
109 if ( UntypedMemberExpr * memberExpr = dynamic_cast< UntypedMemberExpr * >( member ) ) {
110 // construct a new UntypedMemberExpr with the correct structure , and recursively
111 // expand that member expression.
112 MemberTupleExpander expander;
113 UntypedMemberExpr * inner = new UntypedMemberExpr( memberExpr->get_aggregate(), aggr->clone() );
114 UntypedMemberExpr * newMemberExpr = new UntypedMemberExpr( memberExpr->get_member(), inner );
115 inner->location = newMemberExpr->location = loc;
116 memberExpr->set_member(nullptr);
117 memberExpr->set_aggregate(nullptr);
118 delete memberExpr;
119 return newMemberExpr->acceptMutator( expander );
120 } else {
121 // not a member expression, so there is nothing to do but attach and return
122 UntypedMemberExpr * newMemberExpr = new UntypedMemberExpr( member, aggr->clone() );
123 newMemberExpr->location = loc;
124 return newMemberExpr;
125 }
126 }
127 }
128
129 Expression * MemberTupleExpander::mutate( UntypedMemberExpr * memberExpr ) {
130 if ( UntypedTupleExpr * tupleExpr = dynamic_cast< UntypedTupleExpr * > ( memberExpr->get_member() ) ) {
131 Expression * aggr = memberExpr->get_aggregate()->clone()->acceptMutator( *this );
132 // aggregate expressions which might be impure must be wrapped in unique expressions
133 // 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
134 // if ( Tuples::maybeImpureIgnoreUnique( memberExpr->get_aggregate() ) ) aggr = new UniqueExpr( aggr );
135 aggr = new UniqueExpr( aggr );
136 for ( Expression *& expr : tupleExpr->get_exprs() ) {
137 expr = reconstructMemberExpr( expr, aggr, memberExpr->location );
138 expr->location = memberExpr->location;
139 }
140 delete aggr;
141 tupleExpr->location = memberExpr->location;
142 return tupleExpr;
143 } else {
144 // there may be a tuple expr buried in the aggregate
145 // xxx - this is a memory leak
146 UntypedMemberExpr * newMemberExpr = new UntypedMemberExpr( memberExpr->get_member()->clone(), memberExpr->get_aggregate()->acceptMutator( *this ) );
147 newMemberExpr->location = memberExpr->location;
148 return newMemberExpr;
149 }
150 }
151
152 Expression * UniqueExprExpander::postmutate( UniqueExpr * unqExpr ) {
153 const int id = unqExpr->get_id();
154
155 // on first time visiting a unique expr with a particular ID, generate the expression that replaces all UniqueExprs with that ID,
156 // and lookup on subsequent hits. This ensures that all unique exprs with the same ID reference the same variable.
157 if ( ! decls.count( id ) ) {
158 Expression * assignUnq;
159 Expression * var = unqExpr->get_var();
160 if ( unqExpr->get_object() ) {
161 // an object was generated to represent this unique expression -- it should be added to the list of declarations now
162 declsToAddBefore.push_back( unqExpr->get_object() );
163 unqExpr->set_object( nullptr );
164 // steal the expr from the unqExpr
165 assignUnq = UntypedExpr::createAssign( unqExpr->get_var()->clone(), unqExpr->get_expr() );
166 unqExpr->set_expr( nullptr );
167 } else {
168 // steal the already generated assignment to var from the unqExpr - this has been generated by FixInit
169 Expression * expr = unqExpr->get_expr();
170 CommaExpr * commaExpr = safe_dynamic_cast< CommaExpr * >( expr );
171 assignUnq = commaExpr->get_arg1();
172 commaExpr->set_arg1( nullptr );
173 }
174 ObjectDecl * finished = new ObjectDecl( toString( "_unq", id, "_finished_" ), Type::StorageClasses(), LinkageSpec::Cforall, nullptr, new BasicType( Type::Qualifiers(), BasicType::Bool ),
175 new SingleInit( new ConstantExpr( Constant::from_int( 0 ) ) ) );
176 declsToAddBefore.push_back( finished );
177 // (finished ? _unq_expr_N : (_unq_expr_N = <unqExpr->get_expr()>, finished = 1, _unq_expr_N))
178 // This pattern ensures that each unique expression is evaluated once, regardless of evaluation order of the generated C code.
179 Expression * assignFinished = UntypedExpr::createAssign( new VariableExpr(finished), new ConstantExpr( Constant::from_int( 1 ) ) );
180 ConditionalExpr * condExpr = new ConditionalExpr( new VariableExpr( finished ), var->clone(),
181 new CommaExpr( new CommaExpr( assignUnq, assignFinished ), var->clone() ) );
182 condExpr->set_result( var->get_result()->clone() );
183 condExpr->set_env( maybeClone( unqExpr->get_env() ) );
184 decls[id] = condExpr;
185 }
186 delete unqExpr;
187 return decls[id]->clone();
188 }
189
190 Expression * TupleAssignExpander::postmutate( TupleAssignExpr * assnExpr ) {
191 StmtExpr * ret = assnExpr->get_stmtExpr();
192 assnExpr->set_stmtExpr( nullptr );
193 // move env to StmtExpr
194 ret->set_env( assnExpr->get_env() );
195 assnExpr->set_env( nullptr );
196 delete assnExpr;
197 return ret;
198 }
199
200 Type * TupleTypeReplacer::postmutate( TupleType * tupleType ) {
201 unsigned tupleSize = tupleType->size();
202 if ( ! typeMap.count( tupleSize ) ) {
203 // generate struct type to replace tuple type based on the number of components in the tuple
204 StructDecl * decl = new StructDecl( toString( "_tuple", tupleSize, "_" ) );
205 decl->set_body( true );
206 for ( size_t i = 0; i < tupleSize; ++i ) {
207 TypeDecl * tyParam = new TypeDecl( toString( "tuple_param_", tupleSize, "_", i ), Type::StorageClasses(), nullptr, TypeDecl::Any );
208 decl->get_members().push_back( new ObjectDecl( toString("field_", i ), Type::StorageClasses(), LinkageSpec::C, nullptr, new TypeInstType( Type::Qualifiers(), tyParam->get_name(), tyParam ), nullptr ) );
209 decl->get_parameters().push_back( tyParam );
210 }
211 if ( tupleSize == 0 ) {
212 // empty structs are not standard C. Add a dummy field to empty tuples to silence warnings when a compound literal Tuple0 is created.
213 decl->get_members().push_back( new ObjectDecl( "dummy", Type::StorageClasses(), LinkageSpec::C, nullptr, new BasicType( Type::Qualifiers(), BasicType::SignedInt ), nullptr ) );
214 }
215 typeMap[tupleSize] = decl;
216 declsToAddBefore.push_back( decl );
217 }
218 Type::Qualifiers qualifiers = tupleType->get_qualifiers();
219
220 StructDecl * decl = typeMap[tupleSize];
221 StructInstType * newType = new StructInstType( qualifiers, decl );
222 for ( auto p : group_iterate( tupleType->get_types(), decl->get_parameters() ) ) {
223 Type * t = std::get<0>(p);
224 newType->get_parameters().push_back( new TypeExpr( t->clone() ) );
225 }
226 delete tupleType;
227 return newType;
228 }
229
230 Expression * TupleIndexExpander::postmutate( TupleIndexExpr * tupleExpr ) {
231 Expression * tuple = tupleExpr->get_tuple();
232 assert( tuple );
233 tupleExpr->set_tuple( nullptr );
234 unsigned int idx = tupleExpr->get_index();
235 TypeSubstitution * env = tupleExpr->get_env();
236 tupleExpr->set_env( nullptr );
237 delete tupleExpr;
238
239 StructInstType * type = safe_dynamic_cast< StructInstType * >( tuple->get_result() );
240 StructDecl * structDecl = type->get_baseStruct();
241 assert( structDecl->get_members().size() > idx );
242 Declaration * member = *std::next(structDecl->get_members().begin(), idx);
243 MemberExpr * memExpr = new MemberExpr( safe_dynamic_cast< DeclarationWithType * >( member ), tuple );
244 memExpr->set_env( env );
245 return memExpr;
246 }
247
248 Expression * replaceTupleExpr( Type * result, const std::list< Expression * > & exprs, TypeSubstitution * env ) {
249 if ( result->isVoid() ) {
250 // void result - don't need to produce a value for cascading - just output a chain of comma exprs
251 assert( ! exprs.empty() );
252 std::list< Expression * >::const_iterator iter = exprs.begin();
253 Expression * expr = new CastExpr( *iter++ );
254 for ( ; iter != exprs.end(); ++iter ) {
255 expr = new CommaExpr( expr, new CastExpr( *iter ) );
256 }
257 expr->set_env( env );
258 return expr;
259 } else {
260 // typed tuple expression - produce a compound literal which performs each of the expressions
261 // as a distinct part of its initializer - the produced compound literal may be used as part of
262 // another expression
263 std::list< Initializer * > inits;
264 for ( Expression * expr : exprs ) {
265 inits.push_back( new SingleInit( expr ) );
266 }
267 Expression * expr = new CompoundLiteralExpr( result, new ListInit( inits ) );
268 expr->set_env( env );
269 return expr;
270 }
271 }
272
273 Expression * TupleExprExpander::postmutate( TupleExpr * tupleExpr ) {
274 Type * result = tupleExpr->get_result();
275 std::list< Expression * > exprs = tupleExpr->get_exprs();
276 assert( result );
277 TypeSubstitution * env = tupleExpr->get_env();
278
279 // remove data from shell and delete it
280 tupleExpr->set_result( nullptr );
281 tupleExpr->get_exprs().clear();
282 tupleExpr->set_env( nullptr );
283 delete tupleExpr;
284
285 return replaceTupleExpr( result, exprs, env );
286 }
287
288 Type * makeTupleType( const std::list< Expression * > & exprs ) {
289 // produce the TupleType which aggregates the types of the exprs
290 std::list< Type * > types;
291 Type::Qualifiers qualifiers( Type::Const | Type::Volatile | Type::Restrict | Type::Lvalue | Type::Atomic | Type::Mutex );
292 for ( Expression * expr : exprs ) {
293 assert( expr->get_result() );
294 if ( expr->get_result()->isVoid() ) {
295 // if the type of any expr is void, the type of the entire tuple is void
296 return new VoidType( Type::Qualifiers() );
297 }
298 Type * type = expr->get_result()->clone();
299 types.push_back( type );
300 // the qualifiers on the tuple type are the qualifiers that exist on all component types
301 qualifiers &= type->get_qualifiers();
302 } // for
303 if ( exprs.empty() ) qualifiers = Type::Qualifiers();
304 return new TupleType( qualifiers, types );
305 }
306
307 TypeInstType * isTtype( Type * type ) {
308 if ( TypeInstType * inst = dynamic_cast< TypeInstType * >( type ) ) {
309 if ( inst->get_baseType() && inst->get_baseType()->get_kind() == TypeDecl::Ttype ) {
310 return inst;
311 }
312 }
313 return nullptr;
314 }
315
316 namespace {
317 /// 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
318 class ImpurityDetector : public Visitor {
319 public:
320 ImpurityDetector( bool ignoreUnique ) : ignoreUnique( ignoreUnique ) {}
321
322 typedef Visitor Parent;
323 virtual void visit( ApplicationExpr * appExpr ) {
324 if ( DeclarationWithType * function = InitTweak::getFunction( appExpr ) ) {
325 if ( function->get_linkage() == LinkageSpec::Intrinsic ) {
326 if ( function->get_name() == "*?" || function->get_name() == "?[?]" ) {
327 // intrinsic dereference, subscript are pure, but need to recursively look for impurity
328 Parent::visit( appExpr );
329 return;
330 }
331 }
332 }
333 maybeImpure = true;
334 }
335 virtual void visit( UntypedExpr * ) { maybeImpure = true; }
336 virtual void visit( UniqueExpr * unq ) {
337 if ( ignoreUnique ) {
338 // bottom out at unique expression.
339 // The existence of a unique expression doesn't change the purity of an expression.
340 // That is, even if the wrapped expression is impure, the wrapper protects the rest of the expression.
341 return;
342 }
343 maybeAccept( unq->expr, *this );
344 }
345
346 bool maybeImpure = false;
347 bool ignoreUnique;
348 };
349 } // namespace
350
351 bool maybeImpure( Expression * expr ) {
352 ImpurityDetector detector( false );
353 expr->accept( detector );
354 return detector.maybeImpure;
355 }
356
357 bool maybeImpureIgnoreUnique( Expression * expr ) {
358 ImpurityDetector detector( true );
359 expr->accept( detector );
360 return detector.maybeImpure;
361 }
362} // namespace Tuples
363
364// Local Variables: //
365// tab-width: 4 //
366// mode: c++ //
367// compile-command: "make install" //
368// End: //
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