source: src/Tuples/TupleExpansion.cc@ 3bff885

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 3bff885 was e6512c8, checked in by Rob Schluntz <rschlunt@…>, 9 years ago

generate tuples by arity to reduce the number of generated structs
  • Property mode set to 100644
File size: 14.0 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 1 16:40:40 2017
13// Update Count : 3
14//
15
16#include <iterator>
17#include <iostream>
18#include <cassert>
19#include "Tuples.h"
20#include "GenPoly/DeclMutator.h"
21#include "SynTree/Mutator.h"
22#include "SynTree/Statement.h"
23#include "SynTree/Declaration.h"
24#include "SynTree/Type.h"
25#include "SynTree/Expression.h"
26#include "SynTree/Initializer.h"
27#include "SymTab/Mangler.h"
28#include "Common/ScopedMap.h"
29#include "ResolvExpr/typeops.h"
30#include "InitTweak/GenInit.h"
31#include "InitTweak/InitTweak.h"
32
33namespace Tuples {
34 namespace {
35 class MemberTupleExpander final : public Mutator {
36 public:
37 typedef Mutator Parent;
38 using Parent::mutate;
39
40 virtual Expression * mutate( UntypedMemberExpr * memberExpr ) override;
41 };
42
43 class UniqueExprExpander final : public GenPoly::DeclMutator {
44 public:
45 typedef GenPoly::DeclMutator Parent;
46 using Parent::mutate;
47
48 virtual Expression * mutate( UniqueExpr * unqExpr ) override;
49
50 std::map< int, Expression * > decls; // not vector, because order added may not be increasing order
51
52 ~UniqueExprExpander() {
53 for ( std::pair<const int, Expression *> & p : decls ) {
54 delete p.second;
55 }
56 }
57 };
58
59 class TupleAssignExpander : public Mutator {
60 public:
61 typedef Mutator Parent;
62 using Parent::mutate;
63
64 virtual Expression * mutate( TupleAssignExpr * tupleExpr );
65 };
66
67 class TupleTypeReplacer : public GenPoly::DeclMutator {
68 public:
69 typedef GenPoly::DeclMutator Parent;
70 using Parent::mutate;
71
72 virtual Type * mutate( TupleType * tupleType ) override;
73
74 virtual CompoundStmt * mutate( CompoundStmt * stmt ) override {
75 typeMap.beginScope();
76 stmt = Parent::mutate( stmt );
77 typeMap.endScope();
78 return stmt;
79 }
80 private:
81 ScopedMap< int, StructDecl * > typeMap;
82 };
83
84 class TupleIndexExpander final : public Mutator {
85 public:
86 typedef Mutator Parent;
87 using Parent::mutate;
88
89 virtual Expression * mutate( TupleIndexExpr * tupleExpr ) override;
90 };
91
92 class TupleExprExpander final : public Mutator {
93 public:
94 typedef Mutator Parent;
95 using Parent::mutate;
96
97 virtual Expression * mutate( TupleExpr * tupleExpr ) override;
98 };
99 }
100
101 void expandMemberTuples( std::list< Declaration * > & translationUnit ) {
102 MemberTupleExpander expander;
103 mutateAll( translationUnit, expander );
104 }
105
106 void expandUniqueExpr( std::list< Declaration * > & translationUnit ) {
107 UniqueExprExpander unqExpander;
108 unqExpander.mutateDeclarationList( translationUnit );
109 }
110
111 void expandTuples( std::list< Declaration * > & translationUnit ) {
112 TupleAssignExpander assnExpander;
113 mutateAll( translationUnit, assnExpander );
114
115 TupleTypeReplacer replacer;
116 replacer.mutateDeclarationList( translationUnit );
117
118 TupleIndexExpander idxExpander;
119 mutateAll( translationUnit, idxExpander );
120
121 TupleExprExpander exprExpander;
122 mutateAll( translationUnit, exprExpander );
123 }
124
125 namespace {
126 /// given a expression representing the member and an expression representing the aggregate,
127 /// reconstructs a flattened UntypedMemberExpr with the right precedence
128 Expression * reconstructMemberExpr( Expression * member, Expression * aggr ) {
129 if ( UntypedMemberExpr * memberExpr = dynamic_cast< UntypedMemberExpr * >( member ) ) {
130 // construct a new UntypedMemberExpr with the correct structure , and recursively
131 // expand that member expression.
132 MemberTupleExpander expander;
133 UntypedMemberExpr * newMemberExpr = new UntypedMemberExpr( memberExpr->get_member(), new UntypedMemberExpr( memberExpr->get_aggregate(), aggr->clone() ) );
134
135 memberExpr->set_member(nullptr);
136 memberExpr->set_aggregate(nullptr);
137 delete memberExpr;
138 return newMemberExpr->acceptMutator( expander );
139 } else {
140 // not a member expression, so there is nothing to do but attach and return
141 return new UntypedMemberExpr( member, aggr->clone() );
142 }
143 }
144 }
145
146 Expression * MemberTupleExpander::mutate( UntypedMemberExpr * memberExpr ) {
147 if ( UntypedTupleExpr * tupleExpr = dynamic_cast< UntypedTupleExpr * > ( memberExpr->get_member() ) ) {
148 Expression * aggr = memberExpr->get_aggregate()->clone()->acceptMutator( *this );
149 // aggregate expressions which might be impure must be wrapped in unique expressions
150 // 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
151 // if ( Tuples::maybeImpure( memberExpr->get_aggregate() ) ) aggr = new UniqueExpr( aggr );
152 aggr = new UniqueExpr( aggr );
153 for ( Expression *& expr : tupleExpr->get_exprs() ) {
154 expr = reconstructMemberExpr( expr, aggr );
155 }
156 delete aggr;
157 return tupleExpr;
158 } else {
159 // there may be a tuple expr buried in the aggregate
160 // xxx - this is a memory leak
161 return new UntypedMemberExpr( memberExpr->get_member()->clone(), memberExpr->get_aggregate()->acceptMutator( *this ) );
162 }
163 }
164
165 Expression * UniqueExprExpander::mutate( UniqueExpr * unqExpr ) {
166 unqExpr = safe_dynamic_cast< UniqueExpr * > ( Parent::mutate( unqExpr ) );
167 const int id = unqExpr->get_id();
168
169 // on first time visiting a unique expr with a particular ID, generate the expression that replaces all UniqueExprs with that ID,
170 // and lookup on subsequent hits. This ensures that all unique exprs with the same ID reference the same variable.
171 if ( ! decls.count( id ) ) {
172 Expression * assignUnq;
173 Expression * var = unqExpr->get_var();
174 if ( unqExpr->get_object() ) {
175 // an object was generated to represent this unique expression -- it should be added to the list of declarations now
176 addDeclaration( unqExpr->get_object() );
177 unqExpr->set_object( nullptr );
178 // steal the expr from the unqExpr
179 assignUnq = UntypedExpr::createAssign( unqExpr->get_var()->clone(), unqExpr->get_expr() );
180 unqExpr->set_expr( nullptr );
181 } else {
182 // steal the already generated assignment to var from the unqExpr - this has been generated by FixInit
183 Expression * expr = unqExpr->get_expr();
184 CommaExpr * commaExpr = safe_dynamic_cast< CommaExpr * >( expr );
185 assignUnq = commaExpr->get_arg1();
186 commaExpr->set_arg1( nullptr );
187 }
188 BasicType * boolType = new BasicType( Type::Qualifiers(), BasicType::Bool );
189 ObjectDecl * finished = new ObjectDecl( toString( "_unq_expr_finished_", id ), DeclarationNode::NoStorageClass, LinkageSpec::Cforall, nullptr, new BasicType( Type::Qualifiers(), BasicType::Bool ), new SingleInit( new ConstantExpr( Constant( boolType->clone(), "0" ) ), noDesignators ) );
190 addDeclaration( finished );
191 // (finished ? _unq_expr_N : (_unq_expr_N = <unqExpr->get_expr()>, finished = 1, _unq_expr_N))
192 // This pattern ensures that each unique expression is evaluated once, regardless of evaluation order of the generated C code.
193 Expression * assignFinished = UntypedExpr::createAssign( new VariableExpr(finished), new ConstantExpr( Constant( boolType->clone(), "1" ) ) );
194 ConditionalExpr * condExpr = new ConditionalExpr( new VariableExpr( finished ), var->clone(),
195 new CommaExpr( new CommaExpr( assignUnq, assignFinished ), var->clone() ) );
196 condExpr->set_result( var->get_result()->clone() );
197 condExpr->set_env( maybeClone( unqExpr->get_env() ) );
198 decls[id] = condExpr;
199 }
200 delete unqExpr;
201 return decls[id]->clone();
202 }
203
204 Expression * TupleAssignExpander::mutate( TupleAssignExpr * assnExpr ) {
205 assnExpr = safe_dynamic_cast< TupleAssignExpr * >( Parent::mutate( assnExpr ) );
206 StmtExpr * ret = assnExpr->get_stmtExpr();
207 assnExpr->set_stmtExpr( nullptr );
208 // move env to StmtExpr
209 ret->set_env( assnExpr->get_env() );
210 assnExpr->set_env( nullptr );
211 delete assnExpr;
212 return ret;
213 }
214
215 Type * TupleTypeReplacer::mutate( TupleType * tupleType ) {
216 tupleType = safe_dynamic_cast< TupleType * > ( Parent::mutate( tupleType ) );
217 unsigned tupleSize = tupleType->size();
218 if ( ! typeMap.count( tupleSize ) ) {
219 // generate struct type to replace tuple type based on the number of components in the tuple
220 StructDecl * decl = new StructDecl( toString( "_tuple_type_", tupleSize ) );
221 decl->set_body( true );
222 for ( size_t i = 0; i < tupleSize; ++i ) {
223 TypeDecl * tyParam = new TypeDecl( toString("tuple_param_", i), DeclarationNode::NoStorageClass, nullptr, TypeDecl::Any );
224 decl->get_members().push_back( new ObjectDecl( toString("field_", i), DeclarationNode::NoStorageClass, LinkageSpec::C, nullptr, new TypeInstType( Type::Qualifiers(), tyParam->get_name(), tyParam ), nullptr ) );
225 decl->get_parameters().push_back( tyParam );
226 }
227 if ( tupleSize == 0 ) {
228 // empty structs are not standard C. Add a dummy field to empty tuples to silence warnings when a compound literal Tuple0 is created.
229 decl->get_members().push_back( new ObjectDecl( "dummy", DeclarationNode::NoStorageClass, LinkageSpec::C, nullptr, new BasicType( Type::Qualifiers(), BasicType::SignedInt ), nullptr ) );
230 }
231 typeMap[tupleSize] = decl;
232 addDeclaration( decl );
233 }
234 Type::Qualifiers qualifiers = tupleType->get_qualifiers();
235
236 StructDecl * decl = typeMap[tupleSize];
237 StructInstType * newType = new StructInstType( qualifiers, decl );
238 for ( Type * t : *tupleType ) {
239 newType->get_parameters().push_back( new TypeExpr( t->clone() ) );
240 }
241 delete tupleType;
242 return newType;
243 }
244
245 Expression * TupleIndexExpander::mutate( TupleIndexExpr * tupleExpr ) {
246 Expression * tuple = maybeMutate( tupleExpr->get_tuple(), *this );
247 assert( tuple );
248 tupleExpr->set_tuple( nullptr );
249 unsigned int idx = tupleExpr->get_index();
250 TypeSubstitution * env = tupleExpr->get_env();
251 tupleExpr->set_env( nullptr );
252 delete tupleExpr;
253
254 StructInstType * type = safe_dynamic_cast< StructInstType * >( tuple->get_result() );
255 StructDecl * structDecl = type->get_baseStruct();
256 assert( structDecl->get_members().size() > idx );
257 Declaration * member = *std::next(structDecl->get_members().begin(), idx);
258 MemberExpr * memExpr = new MemberExpr( safe_dynamic_cast< DeclarationWithType * >( member ), tuple );
259 memExpr->set_env( env );
260 return memExpr;
261 }
262
263 Expression * replaceTupleExpr( Type * result, const std::list< Expression * > & exprs, TypeSubstitution * env ) {
264 if ( result->isVoid() ) {
265 // void result - don't need to produce a value for cascading - just output a chain of comma exprs
266 assert( ! exprs.empty() );
267 std::list< Expression * >::const_iterator iter = exprs.begin();
268 Expression * expr = new CastExpr( *iter++ );
269 for ( ; iter != exprs.end(); ++iter ) {
270 expr = new CommaExpr( expr, new CastExpr( *iter ) );
271 }
272 expr->set_env( env );
273 return expr;
274 } else {
275 // typed tuple expression - produce a compound literal which performs each of the expressions
276 // as a distinct part of its initializer - the produced compound literal may be used as part of
277 // another expression
278 std::list< Initializer * > inits;
279 for ( Expression * expr : exprs ) {
280 inits.push_back( new SingleInit( expr ) );
281 }
282 Expression * expr = new CompoundLiteralExpr( result, new ListInit( inits ) );
283 expr->set_env( env );
284 return expr;
285 }
286 }
287
288 Expression * TupleExprExpander::mutate( TupleExpr * tupleExpr ) {
289 // recursively expand sub-tuple-expressions
290 tupleExpr = safe_dynamic_cast<TupleExpr *>(Parent::mutate(tupleExpr));
291 Type * result = tupleExpr->get_result();
292 std::list< Expression * > exprs = tupleExpr->get_exprs();
293 assert( result );
294 TypeSubstitution * env = tupleExpr->get_env();
295
296 // remove data from shell and delete it
297 tupleExpr->set_result( nullptr );
298 tupleExpr->get_exprs().clear();
299 tupleExpr->set_env( nullptr );
300 delete tupleExpr;
301
302 return replaceTupleExpr( result, exprs, env );
303 }
304
305 Type * makeTupleType( const std::list< Expression * > & exprs ) {
306 // produce the TupleType which aggregates the types of the exprs
307 TupleType *tupleType = new TupleType( Type::Qualifiers(true, true, true, true, true) );
308 Type::Qualifiers &qualifiers = tupleType->get_qualifiers();
309 for ( Expression * expr : exprs ) {
310 assert( expr->get_result() );
311 if ( expr->get_result()->isVoid() ) {
312 // if the type of any expr is void, the type of the entire tuple is void
313 delete tupleType;
314 return new VoidType( Type::Qualifiers() );
315 }
316 Type * type = expr->get_result()->clone();
317 tupleType->get_types().push_back( type );
318 // the qualifiers on the tuple type are the qualifiers that exist on all component types
319 qualifiers &= type->get_qualifiers();
320 } // for
321 if ( exprs.empty() ) qualifiers = Type::Qualifiers();
322 return tupleType;
323 }
324
325 TypeInstType * isTtype( Type * type ) {
326 if ( TypeInstType * inst = dynamic_cast< TypeInstType * >( type ) ) {
327 if ( inst->get_baseType()->get_kind() == TypeDecl::Ttype ) {
328 return inst;
329 }
330 }
331 return nullptr;
332 }
333
334 namespace {
335 /// 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
336 class ImpurityDetector : public Visitor {
337 public:
338 typedef Visitor Parent;
339 virtual void visit( ApplicationExpr * appExpr ) {
340 if ( DeclarationWithType * function = InitTweak::getFunction( appExpr ) ) {
341 if ( function->get_linkage() == LinkageSpec::Intrinsic ) {
342 if ( function->get_name() == "*?" || function->get_name() == "?[?]" ) {
343 // intrinsic dereference, subscript are pure, but need to recursively look for impurity
344 Parent::visit( appExpr );
345 return;
346 }
347 }
348 }
349 maybeImpure = true;
350 }
351 virtual void visit( UntypedExpr * untypedExpr ) { maybeImpure = true; }
352 bool maybeImpure = false;
353 };
354 } // namespace
355
356 bool maybeImpure( Expression * expr ) {
357 ImpurityDetector detector;
358 expr->accept( detector );
359 return detector.maybeImpure;
360 }
361} // namespace Tuples
362
363// Local Variables: //
364// tab-width: 4 //
365// mode: c++ //
366// compile-command: "make install" //
367// End: //
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