source: src/Tuples/TupleExpansion.cc@ 7abee38

ADT aaron-thesis arm-eh ast-experimental cleanup-dtors enum forall-pointer-decay jacob/cs343-translation jenkins-sandbox new-ast new-ast-unique-expr persistent-indexer pthread-emulation qualifiedEnum
Last change on this file since 7abee38 was e15853c, checked in by Peter A. Buhr <pabuhr@…>, 7 years ago

remove leading underscores in enums for _FloatNN and _Bool
  • Property mode set to 100644
File size: 15.0 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 Feb 13 18:14:12 2019
13// Update Count : 21
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 "InitTweak/InitTweak.h" // for getFunction
24#include "Parser/LinkageSpec.h" // for Spec, C, Intrinsic
25#include "SynTree/Constant.h" // for Constant
26#include "SynTree/Declaration.h" // for StructDecl, DeclarationWithType
27#include "SynTree/Expression.h" // for UntypedMemberExpr, Expression, Uniq...
28#include "SynTree/Label.h" // for operator==, Label
29#include "SynTree/Mutator.h" // for Mutator
30#include "SynTree/Type.h" // for Type, Type::Qualifiers, TupleType
31#include "SynTree/Visitor.h" // for Visitor
32#include "Tuples.h"
33
34class CompoundStmt;
35class TypeSubstitution;
36
37namespace Tuples {
38 namespace {
39 struct MemberTupleExpander final : public WithShortCircuiting, public WithVisitorRef<MemberTupleExpander> {
40 void premutate( UntypedMemberExpr * ) { visit_children = false; }
41 Expression * postmutate( UntypedMemberExpr * memberExpr );
42 };
43
44 struct UniqueExprExpander final : public WithDeclsToAdd {
45 Expression * postmutate( UniqueExpr * unqExpr );
46
47 std::map< int, Expression * > decls; // not vector, because order added may not be increasing order
48
49 ~UniqueExprExpander() {
50 for ( std::pair<const int, Expression *> & p : decls ) {
51 delete p.second;
52 }
53 }
54 };
55
56 struct TupleAssignExpander {
57 Expression * postmutate( TupleAssignExpr * tupleExpr );
58 };
59
60 struct TupleTypeReplacer : public WithDeclsToAdd, public WithGuards, public WithTypeSubstitution {
61 Type * postmutate( TupleType * tupleType );
62
63 void premutate( CompoundStmt * ) {
64 GuardScope( typeMap );
65 }
66 private:
67 ScopedMap< int, StructDecl * > typeMap;
68 };
69
70 struct TupleIndexExpander {
71 Expression * postmutate( TupleIndexExpr * tupleExpr );
72 };
73
74 struct TupleExprExpander final {
75 Expression * postmutate( TupleExpr * tupleExpr );
76 };
77 }
78
79 void expandMemberTuples( std::list< Declaration * > & translationUnit ) {
80 PassVisitor<MemberTupleExpander> expander;
81 mutateAll( translationUnit, expander );
82 }
83
84 void expandUniqueExpr( std::list< Declaration * > & translationUnit ) {
85 PassVisitor<UniqueExprExpander> unqExpander;
86 mutateAll( translationUnit, unqExpander );
87 }
88
89 void expandTuples( std::list< Declaration * > & translationUnit ) {
90 PassVisitor<TupleAssignExpander> assnExpander;
91 mutateAll( translationUnit, assnExpander );
92
93 PassVisitor<TupleTypeReplacer> replacer;
94 mutateAll( translationUnit, replacer );
95
96 PassVisitor<TupleIndexExpander> idxExpander;
97 mutateAll( translationUnit, idxExpander );
98
99 PassVisitor<TupleExprExpander> exprExpander;
100 mutateAll( translationUnit, exprExpander );
101 }
102
103 namespace {
104 /// given a expression representing the member and an expression representing the aggregate,
105 /// reconstructs a flattened UntypedMemberExpr with the right precedence
106 Expression * reconstructMemberExpr( Expression * member, Expression * aggr, CodeLocation & loc ) {
107 if ( UntypedMemberExpr * memberExpr = dynamic_cast< UntypedMemberExpr * >( member ) ) {
108 // construct a new UntypedMemberExpr with the correct structure , and recursively
109 // expand that member expression.
110 PassVisitor<MemberTupleExpander> expander;
111 UntypedMemberExpr * inner = new UntypedMemberExpr( memberExpr->aggregate, aggr->clone() );
112 UntypedMemberExpr * newMemberExpr = new UntypedMemberExpr( memberExpr->member, inner );
113 inner->location = newMemberExpr->location = loc;
114 memberExpr->member = nullptr;
115 memberExpr->aggregate = nullptr;
116 delete memberExpr;
117 return newMemberExpr->acceptMutator( expander );
118 } else {
119 // not a member expression, so there is nothing to do but attach and return
120 UntypedMemberExpr * newMemberExpr = new UntypedMemberExpr( member, aggr->clone() );
121 newMemberExpr->location = loc;
122 return newMemberExpr;
123 }
124 }
125 }
126
127 Expression * MemberTupleExpander::postmutate( UntypedMemberExpr * memberExpr ) {
128 if ( UntypedTupleExpr * tupleExpr = dynamic_cast< UntypedTupleExpr * > ( memberExpr->member ) ) {
129 Expression * aggr = memberExpr->aggregate->clone()->acceptMutator( *visitor );
130 // aggregate expressions which might be impure must be wrapped in unique expressions
131 if ( Tuples::maybeImpureIgnoreUnique( memberExpr->aggregate ) ) aggr = new UniqueExpr( aggr );
132 for ( Expression *& expr : tupleExpr->exprs ) {
133 expr = reconstructMemberExpr( expr, aggr, memberExpr->location );
134 expr->location = memberExpr->location;
135 }
136 delete aggr;
137 tupleExpr->location = memberExpr->location;
138 return tupleExpr;
139 } else {
140 // there may be a tuple expr buried in the aggregate
141 // xxx - this is a memory leak
142 UntypedMemberExpr * newMemberExpr = new UntypedMemberExpr( memberExpr->member->clone(), memberExpr->aggregate->acceptMutator( *visitor ) );
143 newMemberExpr->location = memberExpr->location;
144 return newMemberExpr;
145 }
146 }
147
148 Expression * UniqueExprExpander::postmutate( UniqueExpr * unqExpr ) {
149 const int id = unqExpr->get_id();
150
151 // on first time visiting a unique expr with a particular ID, generate the expression that replaces all UniqueExprs with that ID,
152 // and lookup on subsequent hits. This ensures that all unique exprs with the same ID reference the same variable.
153 if ( ! decls.count( id ) ) {
154 Expression * assignUnq;
155 Expression * var = unqExpr->get_var();
156 if ( unqExpr->get_object() ) {
157 // an object was generated to represent this unique expression -- it should be added to the list of declarations now
158 declsToAddBefore.push_back( unqExpr->get_object() );
159 unqExpr->set_object( nullptr );
160 // steal the expr from the unqExpr
161 assignUnq = UntypedExpr::createAssign( unqExpr->get_var()->clone(), unqExpr->get_expr() );
162 unqExpr->set_expr( nullptr );
163 } else {
164 // steal the already generated assignment to var from the unqExpr - this has been generated by FixInit
165 Expression * expr = unqExpr->get_expr();
166 CommaExpr * commaExpr = strict_dynamic_cast< CommaExpr * >( expr );
167 assignUnq = commaExpr->get_arg1();
168 commaExpr->set_arg1( nullptr );
169 }
170 ObjectDecl * finished = new ObjectDecl( toString( "_unq", id, "_finished_" ), Type::StorageClasses(), LinkageSpec::Cforall, nullptr, new BasicType( Type::Qualifiers(), BasicType::Bool ),
171 new SingleInit( new ConstantExpr( Constant::from_int( 0 ) ) ) );
172 declsToAddBefore.push_back( finished );
173 // (finished ? _unq_expr_N : (_unq_expr_N = <unqExpr->get_expr()>, finished = 1, _unq_expr_N))
174 // This pattern ensures that each unique expression is evaluated once, regardless of evaluation order of the generated C code.
175 Expression * assignFinished = UntypedExpr::createAssign( new VariableExpr(finished), new ConstantExpr( Constant::from_int( 1 ) ) );
176 ConditionalExpr * condExpr = new ConditionalExpr( new VariableExpr( finished ), var->clone(),
177 new CommaExpr( new CommaExpr( assignUnq, assignFinished ), var->clone() ) );
178 condExpr->set_result( var->get_result()->clone() );
179 condExpr->set_env( maybeClone( unqExpr->get_env() ) );
180 decls[id] = condExpr;
181 }
182 delete unqExpr;
183 return decls[id]->clone();
184 }
185
186 Expression * TupleAssignExpander::postmutate( TupleAssignExpr * assnExpr ) {
187 StmtExpr * ret = assnExpr->get_stmtExpr();
188 assnExpr->set_stmtExpr( nullptr );
189 // move env to StmtExpr
190 ret->set_env( assnExpr->get_env() );
191 assnExpr->set_env( nullptr );
192 delete assnExpr;
193 return ret;
194 }
195
196 Type * TupleTypeReplacer::postmutate( TupleType * tupleType ) {
197 unsigned tupleSize = tupleType->size();
198 if ( ! typeMap.count( tupleSize ) ) {
199 // generate struct type to replace tuple type based on the number of components in the tuple
200 StructDecl * decl = new StructDecl( toString( "_tuple", tupleSize, "_" ) );
201 decl->location = tupleType->location;
202 decl->set_body( true );
203 for ( size_t i = 0; i < tupleSize; ++i ) {
204 TypeDecl * tyParam = new TypeDecl( toString( "tuple_param_", tupleSize, "_", i ), Type::StorageClasses(), nullptr, TypeDecl::Dtype, true );
205 decl->get_members().push_back( new ObjectDecl( toString("field_", i ), Type::StorageClasses(), LinkageSpec::C, nullptr, new TypeInstType( Type::Qualifiers(), tyParam->get_name(), tyParam ), nullptr ) );
206 decl->get_parameters().push_back( tyParam );
207 }
208 if ( tupleSize == 0 ) {
209 // empty structs are not standard C. Add a dummy field to empty tuples to silence warnings when a compound literal Tuple0 is created.
210 decl->get_members().push_back( new ObjectDecl( "dummy", Type::StorageClasses(), LinkageSpec::C, nullptr, new BasicType( Type::Qualifiers(), BasicType::SignedInt ), nullptr ) );
211 }
212 typeMap[tupleSize] = decl;
213 declsToAddBefore.push_back( decl );
214 }
215 Type::Qualifiers qualifiers = tupleType->get_qualifiers();
216
217 StructDecl * decl = typeMap[tupleSize];
218 StructInstType * newType = new StructInstType( qualifiers, decl );
219 for ( auto p : group_iterate( tupleType->get_types(), decl->get_parameters() ) ) {
220 Type * t = std::get<0>(p);
221 newType->get_parameters().push_back( new TypeExpr( t->clone() ) );
222 }
223 delete tupleType;
224 return newType;
225 }
226
227 Expression * TupleIndexExpander::postmutate( TupleIndexExpr * tupleExpr ) {
228 Expression * tuple = tupleExpr->tuple;
229 assert( tuple );
230 tupleExpr->tuple = nullptr;
231 unsigned int idx = tupleExpr->index;
232 TypeSubstitution * env = tupleExpr->env;
233 tupleExpr->env = nullptr;
234 delete tupleExpr;
235
236 if ( TupleExpr * tupleExpr = dynamic_cast< TupleExpr * > ( tuple ) ) {
237 if ( ! maybeImpureIgnoreUnique( tupleExpr ) ) {
238 // optimization: definitely pure tuple expr => can reduce to the only relevant component.
239 assert( tupleExpr->exprs.size() > idx );
240 Expression *& expr = *std::next(tupleExpr->exprs.begin(), idx);
241 Expression * ret = expr;
242 ret->env = env;
243 expr = nullptr; // remove from list so it can safely be deleted
244 delete tupleExpr;
245 return ret;
246 }
247 }
248
249 StructInstType * type = strict_dynamic_cast< StructInstType * >( tuple->result );
250 StructDecl * structDecl = type->baseStruct;
251 assert( structDecl->members.size() > idx );
252 Declaration * member = *std::next(structDecl->members.begin(), idx);
253 MemberExpr * memExpr = new MemberExpr( strict_dynamic_cast< DeclarationWithType * >( member ), tuple );
254 memExpr->env = env;
255 return memExpr;
256 }
257
258 Expression * replaceTupleExpr( Type * result, const std::list< Expression * > & exprs, TypeSubstitution * env ) {
259 if ( result->isVoid() ) {
260 // void result - don't need to produce a value for cascading - just output a chain of comma exprs
261 assert( ! exprs.empty() );
262 std::list< Expression * >::const_iterator iter = exprs.begin();
263 Expression * expr = new CastExpr( *iter++ );
264 for ( ; iter != exprs.end(); ++iter ) {
265 expr = new CommaExpr( expr, new CastExpr( *iter ) );
266 }
267 expr->set_env( env );
268 return expr;
269 } else {
270 // typed tuple expression - produce a compound literal which performs each of the expressions
271 // as a distinct part of its initializer - the produced compound literal may be used as part of
272 // another expression
273 std::list< Initializer * > inits;
274 for ( Expression * expr : exprs ) {
275 inits.push_back( new SingleInit( expr ) );
276 }
277 Expression * expr = new CompoundLiteralExpr( result, new ListInit( inits ) );
278 expr->set_env( env );
279 return expr;
280 }
281 }
282
283 Expression * TupleExprExpander::postmutate( TupleExpr * tupleExpr ) {
284 Type * result = tupleExpr->get_result();
285 std::list< Expression * > exprs = tupleExpr->get_exprs();
286 assert( result );
287 TypeSubstitution * env = tupleExpr->get_env();
288
289 // remove data from shell and delete it
290 tupleExpr->set_result( nullptr );
291 tupleExpr->get_exprs().clear();
292 tupleExpr->set_env( nullptr );
293 delete tupleExpr;
294
295 return replaceTupleExpr( result, exprs, env );
296 }
297
298 Type * makeTupleType( const std::list< Expression * > & exprs ) {
299 // produce the TupleType which aggregates the types of the exprs
300 std::list< Type * > types;
301 Type::Qualifiers qualifiers( Type::Const | Type::Volatile | Type::Restrict | Type::Lvalue | Type::Atomic | Type::Mutex );
302 for ( Expression * expr : exprs ) {
303 assert( expr->get_result() );
304 if ( expr->get_result()->isVoid() ) {
305 // if the type of any expr is void, the type of the entire tuple is void
306 return new VoidType( Type::Qualifiers() );
307 }
308 Type * type = expr->get_result()->clone();
309 types.push_back( type );
310 // the qualifiers on the tuple type are the qualifiers that exist on all component types
311 qualifiers &= type->get_qualifiers();
312 } // for
313 if ( exprs.empty() ) qualifiers = Type::Qualifiers();
314 return new TupleType( qualifiers, types );
315 }
316
317 TypeInstType * isTtype( Type * type ) {
318 if ( TypeInstType * inst = dynamic_cast< TypeInstType * >( type ) ) {
319 if ( inst->get_baseType() && inst->get_baseType()->get_kind() == TypeDecl::Ttype ) {
320 return inst;
321 }
322 }
323 return nullptr;
324 }
325
326 namespace {
327 /// 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
328 struct ImpurityDetector : public WithShortCircuiting {
329 ImpurityDetector( bool ignoreUnique ) : ignoreUnique( ignoreUnique ) {}
330
331 void previsit( ApplicationExpr * appExpr ) {
332 visit_children = false;
333 if ( DeclarationWithType * function = InitTweak::getFunction( appExpr ) ) {
334 if ( function->get_linkage() == LinkageSpec::Intrinsic ) {
335 if ( function->get_name() == "*?" || function->get_name() == "?[?]" ) {
336 // intrinsic dereference, subscript are pure, but need to recursively look for impurity
337 visit_children = true;
338 return;
339 }
340 }
341 }
342 maybeImpure = true;
343 }
344 void previsit( UntypedExpr * ) { maybeImpure = true; visit_children = false; }
345 void previsit( UniqueExpr * ) {
346 if ( ignoreUnique ) {
347 // bottom out at unique expression.
348 // The existence of a unique expression doesn't change the purity of an expression.
349 // That is, even if the wrapped expression is impure, the wrapper protects the rest of the expression.
350 visit_children = false;
351 return;
352 }
353 }
354
355 bool maybeImpure = false;
356 bool ignoreUnique;
357 };
358 } // namespace
359
360 bool maybeImpure( Expression * expr ) {
361 PassVisitor<ImpurityDetector> detector( false );
362 expr->accept( detector );
363 return detector.pass.maybeImpure;
364 }
365
366 bool maybeImpureIgnoreUnique( Expression * expr ) {
367 PassVisitor<ImpurityDetector> detector( true );
368 expr->accept( detector );
369 return detector.pass.maybeImpure;
370 }
371} // namespace Tuples
372
373// Local Variables: //
374// tab-width: 4 //
375// mode: c++ //
376// compile-command: "make install" //
377// End: //
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