source: src/Tuples/TupleExpansion.cc@ f196351

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 f196351 was c92c09c, checked in by Rob Schluntz <rschlunt@…>, 8 years ago

Add tuple parameter bindings to type substitution
  • Property mode set to 100644
File size: 14.3 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 <iterator>
17#include <iostream>
18#include <cassert>
19#include "Tuples.h"
20#include "Common/PassVisitor.h"
21#include "Common/ScopedMap.h"
22#include "GenPoly/DeclMutator.h"
23#include "InitTweak/GenInit.h"
24#include "InitTweak/InitTweak.h"
25#include "ResolvExpr/typeops.h"
26#include "SymTab/Mangler.h"
27#include "SynTree/Declaration.h"
28#include "SynTree/Expression.h"
29#include "SynTree/Initializer.h"
30#include "SynTree/Mutator.h"
31#include "SynTree/Statement.h"
32#include "SynTree/Type.h"
33
34namespace Tuples {
35 namespace {
36 class MemberTupleExpander final : public Mutator {
37 public:
38 typedef Mutator Parent;
39 using Parent::mutate;
40
41 virtual Expression * mutate( UntypedMemberExpr * memberExpr ) override;
42 };
43
44 class UniqueExprExpander final : public GenPoly::DeclMutator {
45 public:
46 typedef GenPoly::DeclMutator Parent;
47 using Parent::mutate;
48
49 virtual Expression * mutate( UniqueExpr * unqExpr ) override;
50
51 std::map< int, Expression * > decls; // not vector, because order added may not be increasing order
52
53 ~UniqueExprExpander() {
54 for ( std::pair<const int, Expression *> & p : decls ) {
55 delete p.second;
56 }
57 }
58 };
59
60 class TupleAssignExpander : public Mutator {
61 public:
62 typedef Mutator Parent;
63 using Parent::mutate;
64
65 virtual Expression * mutate( TupleAssignExpr * tupleExpr );
66 };
67
68 struct TupleTypeReplacer : public WithDeclsToAdd, public WithGuards, public WithTypeSubstitution {
69 Type * postmutate( TupleType * tupleType );
70
71 void premutate( CompoundStmt * ) {
72 GuardScope( typeMap );
73 }
74 private:
75 ScopedMap< int, StructDecl * > typeMap;
76 };
77
78 class TupleIndexExpander {
79 public:
80 Expression * postmutate( TupleIndexExpr * tupleExpr );
81 };
82
83 class TupleExprExpander final : public Mutator {
84 public:
85 typedef Mutator Parent;
86 using Parent::mutate;
87
88 virtual Expression * mutate( TupleExpr * tupleExpr ) override;
89 };
90 }
91
92 void expandMemberTuples( std::list< Declaration * > & translationUnit ) {
93 MemberTupleExpander expander;
94 mutateAll( translationUnit, expander );
95 }
96
97 void expandUniqueExpr( std::list< Declaration * > & translationUnit ) {
98 UniqueExprExpander unqExpander;
99 unqExpander.mutateDeclarationList( translationUnit );
100 }
101
102 void expandTuples( std::list< Declaration * > & translationUnit ) {
103 TupleAssignExpander assnExpander;
104 mutateAll( translationUnit, assnExpander );
105
106 PassVisitor<TupleTypeReplacer> replacer;
107 mutateAll( translationUnit, replacer );
108
109 PassVisitor<TupleIndexExpander> idxExpander;
110 mutateAll( translationUnit, idxExpander );
111
112 TupleExprExpander exprExpander;
113 mutateAll( translationUnit, exprExpander );
114 }
115
116 namespace {
117 /// given a expression representing the member and an expression representing the aggregate,
118 /// reconstructs a flattened UntypedMemberExpr with the right precedence
119 Expression * reconstructMemberExpr( Expression * member, Expression * aggr, CodeLocation & loc ) {
120 if ( UntypedMemberExpr * memberExpr = dynamic_cast< UntypedMemberExpr * >( member ) ) {
121 // construct a new UntypedMemberExpr with the correct structure , and recursively
122 // expand that member expression.
123 MemberTupleExpander expander;
124 UntypedMemberExpr * inner = new UntypedMemberExpr( memberExpr->get_aggregate(), aggr->clone() );
125 UntypedMemberExpr * newMemberExpr = new UntypedMemberExpr( memberExpr->get_member(), inner );
126 inner->location = newMemberExpr->location = loc;
127 memberExpr->set_member(nullptr);
128 memberExpr->set_aggregate(nullptr);
129 delete memberExpr;
130 return newMemberExpr->acceptMutator( expander );
131 } else {
132 // not a member expression, so there is nothing to do but attach and return
133 UntypedMemberExpr * newMemberExpr = new UntypedMemberExpr( member, aggr->clone() );
134 newMemberExpr->location = loc;
135 return newMemberExpr;
136 }
137 }
138 }
139
140 Expression * MemberTupleExpander::mutate( UntypedMemberExpr * memberExpr ) {
141 if ( UntypedTupleExpr * tupleExpr = dynamic_cast< UntypedTupleExpr * > ( memberExpr->get_member() ) ) {
142 Expression * aggr = memberExpr->get_aggregate()->clone()->acceptMutator( *this );
143 // aggregate expressions which might be impure must be wrapped in unique expressions
144 // 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
145 // if ( Tuples::maybeImpure( memberExpr->get_aggregate() ) ) aggr = new UniqueExpr( aggr );
146 aggr = new UniqueExpr( aggr );
147 for ( Expression *& expr : tupleExpr->get_exprs() ) {
148 expr = reconstructMemberExpr( expr, aggr, memberExpr->location );
149 expr->location = memberExpr->location;
150 }
151 delete aggr;
152 tupleExpr->location = memberExpr->location;
153 return tupleExpr;
154 } else {
155 // there may be a tuple expr buried in the aggregate
156 // xxx - this is a memory leak
157 UntypedMemberExpr * newMemberExpr = new UntypedMemberExpr( memberExpr->get_member()->clone(), memberExpr->get_aggregate()->acceptMutator( *this ) );
158 newMemberExpr->location = memberExpr->location;
159 return newMemberExpr;
160 }
161 }
162
163 Expression * UniqueExprExpander::mutate( UniqueExpr * unqExpr ) {
164 unqExpr = safe_dynamic_cast< UniqueExpr * > ( Parent::mutate( unqExpr ) );
165 const int id = unqExpr->get_id();
166
167 // on first time visiting a unique expr with a particular ID, generate the expression that replaces all UniqueExprs with that ID,
168 // and lookup on subsequent hits. This ensures that all unique exprs with the same ID reference the same variable.
169 if ( ! decls.count( id ) ) {
170 Expression * assignUnq;
171 Expression * var = unqExpr->get_var();
172 if ( unqExpr->get_object() ) {
173 // an object was generated to represent this unique expression -- it should be added to the list of declarations now
174 addDeclaration( unqExpr->get_object() );
175 unqExpr->set_object( nullptr );
176 // steal the expr from the unqExpr
177 assignUnq = UntypedExpr::createAssign( unqExpr->get_var()->clone(), unqExpr->get_expr() );
178 unqExpr->set_expr( nullptr );
179 } else {
180 // steal the already generated assignment to var from the unqExpr - this has been generated by FixInit
181 Expression * expr = unqExpr->get_expr();
182 CommaExpr * commaExpr = safe_dynamic_cast< CommaExpr * >( expr );
183 assignUnq = commaExpr->get_arg1();
184 commaExpr->set_arg1( nullptr );
185 }
186 ObjectDecl * finished = new ObjectDecl( toString( "_unq", id, "_finished_" ), Type::StorageClasses(), LinkageSpec::Cforall, nullptr, new BasicType( Type::Qualifiers(), BasicType::Bool ),
187 new SingleInit( new ConstantExpr( Constant::from_int( 0 ) ) ) );
188 addDeclaration( finished );
189 // (finished ? _unq_expr_N : (_unq_expr_N = <unqExpr->get_expr()>, finished = 1, _unq_expr_N))
190 // This pattern ensures that each unique expression is evaluated once, regardless of evaluation order of the generated C code.
191 Expression * assignFinished = UntypedExpr::createAssign( new VariableExpr(finished), new ConstantExpr( Constant::from_int( 1 ) ) );
192 ConditionalExpr * condExpr = new ConditionalExpr( new VariableExpr( finished ), var->clone(),
193 new CommaExpr( new CommaExpr( assignUnq, assignFinished ), var->clone() ) );
194 condExpr->set_result( var->get_result()->clone() );
195 condExpr->set_env( maybeClone( unqExpr->get_env() ) );
196 decls[id] = condExpr;
197 }
198 delete unqExpr;
199 return decls[id]->clone();
200 }
201
202 Expression * TupleAssignExpander::mutate( TupleAssignExpr * assnExpr ) {
203 assnExpr = safe_dynamic_cast< TupleAssignExpr * >( Parent::mutate( assnExpr ) );
204 StmtExpr * ret = assnExpr->get_stmtExpr();
205 assnExpr->set_stmtExpr( nullptr );
206 // move env to StmtExpr
207 ret->set_env( assnExpr->get_env() );
208 assnExpr->set_env( nullptr );
209 delete assnExpr;
210 return ret;
211 }
212
213 Type * TupleTypeReplacer::postmutate( TupleType * tupleType ) {
214 unsigned tupleSize = tupleType->size();
215 if ( ! typeMap.count( tupleSize ) ) {
216 // generate struct type to replace tuple type based on the number of components in the tuple
217 StructDecl * decl = new StructDecl( toString( "_tuple", tupleSize, "_" ) );
218 decl->set_body( true );
219 for ( size_t i = 0; i < tupleSize; ++i ) {
220 TypeDecl * tyParam = new TypeDecl( toString( "tuple_param_", tupleSize, "_", i ), Type::StorageClasses(), nullptr, TypeDecl::Any );
221 decl->get_members().push_back( new ObjectDecl( toString("field_", i ), Type::StorageClasses(), LinkageSpec::C, nullptr, new TypeInstType( Type::Qualifiers(), tyParam->get_name(), tyParam ), nullptr ) );
222 decl->get_parameters().push_back( tyParam );
223 }
224 if ( tupleSize == 0 ) {
225 // empty structs are not standard C. Add a dummy field to empty tuples to silence warnings when a compound literal Tuple0 is created.
226 decl->get_members().push_back( new ObjectDecl( "dummy", Type::StorageClasses(), LinkageSpec::C, nullptr, new BasicType( Type::Qualifiers(), BasicType::SignedInt ), nullptr ) );
227 }
228 typeMap[tupleSize] = decl;
229 declsToAddBefore.push_back( decl );
230 }
231 Type::Qualifiers qualifiers = tupleType->get_qualifiers();
232
233 StructDecl * decl = typeMap[tupleSize];
234 StructInstType * newType = new StructInstType( qualifiers, decl );
235 for ( auto p : group_iterate( tupleType->get_types(), decl->get_parameters() ) ) {
236 Type * t = std::get<0>(p);
237 TypeDecl * td = std::get<1>(p);
238 newType->get_parameters().push_back( new TypeExpr( t->clone() ) );
239 if ( env ) {
240 // add bindings to the type environment.
241 // xxx - This may not be sufficient, it may be necessary to rename type variables on StructInstType?
242 env->add( td->get_name(), t->clone() );
243 }
244 }
245 delete tupleType;
246 return newType;
247 }
248
249 Expression * TupleIndexExpander::postmutate( TupleIndexExpr * tupleExpr ) {
250 Expression * tuple = tupleExpr->get_tuple();
251 assert( tuple );
252 tupleExpr->set_tuple( nullptr );
253 unsigned int idx = tupleExpr->get_index();
254 TypeSubstitution * env = tupleExpr->get_env();
255 tupleExpr->set_env( nullptr );
256 delete tupleExpr;
257
258 StructInstType * type = safe_dynamic_cast< StructInstType * >( tuple->get_result() );
259 StructDecl * structDecl = type->get_baseStruct();
260 assert( structDecl->get_members().size() > idx );
261 Declaration * member = *std::next(structDecl->get_members().begin(), idx);
262 MemberExpr * memExpr = new MemberExpr( safe_dynamic_cast< DeclarationWithType * >( member ), tuple );
263 memExpr->set_env( env );
264 return memExpr;
265 }
266
267 Expression * replaceTupleExpr( Type * result, const std::list< Expression * > & exprs, TypeSubstitution * env ) {
268 if ( result->isVoid() ) {
269 // void result - don't need to produce a value for cascading - just output a chain of comma exprs
270 assert( ! exprs.empty() );
271 std::list< Expression * >::const_iterator iter = exprs.begin();
272 Expression * expr = new CastExpr( *iter++ );
273 for ( ; iter != exprs.end(); ++iter ) {
274 expr = new CommaExpr( expr, new CastExpr( *iter ) );
275 }
276 expr->set_env( env );
277 return expr;
278 } else {
279 // typed tuple expression - produce a compound literal which performs each of the expressions
280 // as a distinct part of its initializer - the produced compound literal may be used as part of
281 // another expression
282 std::list< Initializer * > inits;
283 for ( Expression * expr : exprs ) {
284 inits.push_back( new SingleInit( expr ) );
285 }
286 Expression * expr = new CompoundLiteralExpr( result, new ListInit( inits ) );
287 expr->set_env( env );
288 return expr;
289 }
290 }
291
292 Expression * TupleExprExpander::mutate( TupleExpr * tupleExpr ) {
293 // recursively expand sub-tuple-expressions
294 tupleExpr = safe_dynamic_cast<TupleExpr *>(Parent::mutate(tupleExpr));
295 Type * result = tupleExpr->get_result();
296 std::list< Expression * > exprs = tupleExpr->get_exprs();
297 assert( result );
298 TypeSubstitution * env = tupleExpr->get_env();
299
300 // remove data from shell and delete it
301 tupleExpr->set_result( nullptr );
302 tupleExpr->get_exprs().clear();
303 tupleExpr->set_env( nullptr );
304 delete tupleExpr;
305
306 return replaceTupleExpr( result, exprs, env );
307 }
308
309 Type * makeTupleType( const std::list< Expression * > & exprs ) {
310 // produce the TupleType which aggregates the types of the exprs
311 std::list< Type * > types;
312 Type::Qualifiers qualifiers( Type::Const | Type::Volatile | Type::Restrict | Type::Lvalue | Type::Atomic | Type::Mutex );
313 for ( Expression * expr : exprs ) {
314 assert( expr->get_result() );
315 if ( expr->get_result()->isVoid() ) {
316 // if the type of any expr is void, the type of the entire tuple is void
317 return new VoidType( Type::Qualifiers() );
318 }
319 Type * type = expr->get_result()->clone();
320 types.push_back( type );
321 // the qualifiers on the tuple type are the qualifiers that exist on all component types
322 qualifiers &= type->get_qualifiers();
323 } // for
324 if ( exprs.empty() ) qualifiers = Type::Qualifiers();
325 return new TupleType( qualifiers, types );
326 }
327
328 TypeInstType * isTtype( Type * type ) {
329 if ( TypeInstType * inst = dynamic_cast< TypeInstType * >( type ) ) {
330 if ( inst->get_baseType() && inst->get_baseType()->get_kind() == TypeDecl::Ttype ) {
331 return inst;
332 }
333 }
334 return nullptr;
335 }
336
337 namespace {
338 /// 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
339 class ImpurityDetector : public Visitor {
340 public:
341 typedef Visitor Parent;
342 virtual void visit( ApplicationExpr * appExpr ) {
343 if ( DeclarationWithType * function = InitTweak::getFunction( appExpr ) ) {
344 if ( function->get_linkage() == LinkageSpec::Intrinsic ) {
345 if ( function->get_name() == "*?" || function->get_name() == "?[?]" ) {
346 // intrinsic dereference, subscript are pure, but need to recursively look for impurity
347 Parent::visit( appExpr );
348 return;
349 }
350 }
351 }
352 maybeImpure = true;
353 }
354 virtual void visit( __attribute__((unused)) UntypedExpr * untypedExpr ) { maybeImpure = true; }
355 bool maybeImpure = false;
356 };
357 } // namespace
358
359 bool maybeImpure( Expression * expr ) {
360 ImpurityDetector detector;
361 expr->accept( detector );
362 return detector.maybeImpure;
363 }
364} // namespace Tuples
365
366// Local Variables: //
367// tab-width: 4 //
368// mode: c++ //
369// compile-command: "make install" //
370// End: //
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