Changes in src/ResolvExpr/ResolveAssertions.cc [493a992:e1f7eef]

File:

• src/ResolvExpr/ResolveAssertions.cc (modified) (14 diffs)

src/ResolvExpr/ResolveAssertions.cc

@@ -20 +20 @@
 #include <list>                     // for list
 #include <memory>                   // for unique_ptr
-#include <sstream>                  // for ostringstream
-#include <string>                   // for string
+#include <string>
 #include <unordered_map>            // for unordered_map, unordered_multimap
 #include <utility>                  // for move
@@ -28 +27 @@
 #include "Alternative.h"            // for Alternative, AssertionItem, AssertionList
 #include "Common/FilterCombos.h"    // for filterCombos
-#include "Common/Indenter.h"        // for Indenter
 #include "Common/utility.h"         // for sort_mins
 #include "ResolvExpr/RenameVars.h"  // for renameTyVars
@@ -35 +33 @@
 #include "SynTree/Expression.h"     // for InferredParams
 #include "TypeEnvironment.h"        // for TypeEnvironment, etc.
-#include "typeops.h"                // for adjustExprType, specCost
+#include "typeops.h"                // for adjustExprType
 #include "Unify.h"                  // for unify
 
@@ -58 +56 @@
         using CandidateList = std::vector<AssnCandidate>;
 
+        /// Unique identifier for a yet-to-be-resolved assertion
+        struct AssnId {
+                DeclarationWithType* decl;  ///< Declaration of assertion
+                AssertionSetValue info;     ///< Information about assertion
+
+                AssnId(DeclarationWithType* decl, const AssertionSetValue& info) : decl(decl), info(info) {}
+        };
+
+        /// Cached assertion items
+        struct AssnCacheItem {
+                CandidateList matches;         ///< Possible matches for this assertion
+                std::vector<AssnId> deferIds;  ///< Deferred assertions which resolve to this item
+
+                AssnCacheItem( CandidateList&& m ) : matches(std::move(m)), deferIds() {}
+        };
+
+        /// Cache of resolved assertions
+        using AssnCache = std::unordered_map<std::string, AssnCacheItem>;
+
         /// Reference to single deferred item
         struct DeferRef {
-                const DeclarationWithType* decl;
-                const AssertionSetValue& info;
+                const AssnCacheItem& item;
                 const AssnCandidate& match;
         };
@@ -68 +84 @@
         /// Acts like indexed list of DeferRef
         struct DeferItem {
-                const DeclarationWithType* decl;
-                const AssertionSetValue& info;
-                CandidateList matches;
-
-                DeferItem( DeclarationWithType* decl, const AssertionSetValue& info, CandidateList&& matches )
-                : decl(decl), info(info), matches(std::move(matches)) {}
-
-                bool empty() const { return matches.empty(); }
-
-                CandidateList::size_type size() const { return matches.size(); }
-
-                DeferRef operator[] ( unsigned i ) const { return { decl, info, matches[i] }; }
+                const AssnCache* cache;     ///< Cache storing assertion item
+                std::string key;            ///< Key into cache
+                
+                DeferItem( const AssnCache& cache, const std::string& key ) : cache(&cache), key(key) {}
+
+                bool empty() const { return cache->at(key).matches.empty(); }
+
+                CandidateList::size_type size() const { return cache->at(key).matches.size(); }
+
+                DeferRef operator[] ( unsigned i ) const {
+                        const AssnCacheItem& item = cache->at(key);
+                        return { item, item.matches[i] };
+                }
+
+                // sortable by key
+                // TODO look into optimizing combination process with other sort orders (e.g. by number 
+                // of matches in candidate)
+                bool operator< ( const DeferItem& o ) const { return key < o.key; }
+                bool operator== ( const DeferItem& o ) const { return key == o.key; }
         };
 
@@ -154 +177 @@
                                 for ( const auto& assn : x.assns ) {
                                         k += computeConversionCost( 
-                                                assn.match.adjType, assn.decl->get_type(), indexer, x.env );
-                                        
-                                        // mark vars+specialization cost on function-type assertions
-                                        PointerType* ptr = dynamic_cast< PointerType* >( assn.decl->get_type() );
-                                        if ( ! ptr ) continue;
-                                        FunctionType* func = dynamic_cast< FunctionType* >( ptr->base );
-                                        if ( ! func ) continue;
-                                        
-                                        for ( DeclarationWithType* formal : func->parameters ) {
-                                                k.decSpec( specCost( formal->get_type() ) );
-                                        }
-                                        k.incVar( func->forall.size() );
-                                        for ( TypeDecl* td : func->forall ) {
-                                                k.decSpec( td->assertions.size() );
-                                        }
+                                                assn.match.adjType, assn.item.deferIds[0].decl->get_type(), indexer, 
+                                                x.env );
                                 }
                                 it = cache.emplace_hint( it, &x, k );
@@ -239 +249 @@
 
         /// Resolve a single assertion, in context
-        bool resolveAssertion( AssertionItem& assn, ResnState& resn ) {
+        bool resolveAssertion( AssertionItem& assn, ResnState& resn, AssnCache& cache ) {
                 // skip unused assertions
                 if ( ! assn.info.isUsed ) return true;
 
-                // lookup candidates for this assertion
-                std::list< SymTab::Indexer::IdData > candidates;
-                resn.indexer.lookupId( assn.decl->name, candidates );
-
-                // find the candidates that unify with the desired type
-                CandidateList matches;
-                for ( const auto& cdata : candidates ) {
-                        DeclarationWithType* candidate = cdata.id;
-
-                        // build independent unification context for candidate
-                        AssertionSet have, newNeed;
-                        TypeEnvironment newEnv{ resn.alt.env };
-                        OpenVarSet newOpenVars{ resn.alt.openVars };
-                        Type* adjType = candidate->get_type()->clone();
-                        adjustExprType( adjType, newEnv, resn.indexer );
-                        renameTyVars( adjType );
-
-                        // keep unifying candidates
-                        if ( unify( assn.decl->get_type(), adjType, newEnv, newNeed, have, newOpenVars, 
-                                        resn.indexer ) ) {
-                                // set up binding slot for recursive assertions
-                                UniqueId crntResnSlot = 0;
-                                if ( ! newNeed.empty() ) {
-                                        crntResnSlot = ++globalResnSlot;
-                                        for ( auto& a : newNeed ) {
-                                                a.second.resnSlot = crntResnSlot;
+                // check cache for this assertion
+                std::string assnKey = SymTab::Mangler::mangleAssnKey( assn.decl, resn.alt.env );
+                auto it = cache.find( assnKey );
+
+                // attempt to resolve assertion if this is the first time seen
+                if ( it == cache.end() ) {
+                        // lookup candidates for this assertion
+                        std::list< SymTab::Indexer::IdData > candidates;
+                        resn.indexer.lookupId( assn.decl->name, candidates );
+
+                        // find the candidates that unify with the desired type
+                        CandidateList matches;
+                        for ( const auto& cdata : candidates ) {
+                                DeclarationWithType* candidate = cdata.id;
+
+                                // build independent unification context for candidate
+                                AssertionSet have, newNeed;
+                                TypeEnvironment newEnv{ resn.alt.env };
+                                OpenVarSet newOpenVars{ resn.alt.openVars };
+                                Type* adjType = candidate->get_type()->clone();
+                                adjustExprType( adjType, newEnv, resn.indexer );
+                                renameTyVars( adjType );
+
+                                // keep unifying candidates
+                                if ( unify( assn.decl->get_type(), adjType, newEnv, newNeed, have, newOpenVars, 
+                                                resn.indexer ) ) {
+                                        // set up binding slot for recursive assertions
+                                        UniqueId crntResnSlot = 0;
+                                        if ( ! newNeed.empty() ) {
+                                                crntResnSlot = ++globalResnSlot;
+                                                for ( auto& a : newNeed ) {
+                                                        a.second.resnSlot = crntResnSlot;
+                                                }
                                         }
-                                }
-
-                                matches.emplace_back( cdata, adjType, std::move(newEnv), std::move(have), 
-                                        std::move(newNeed), std::move(newOpenVars), crntResnSlot );
-                        } else {
-                                delete adjType;
+
+                                        matches.emplace_back( cdata, adjType, std::move(newEnv), std::move(have), 
+                                                std::move(newNeed), std::move(newOpenVars), crntResnSlot );
+                                } else {
+                                        delete adjType;
+                                }
                         }
-                }
+
+                        it = cache.emplace_hint( it, assnKey, AssnCacheItem{ std::move(matches) } );
+                }
+
+                CandidateList& matches = it->second.matches;
 
                 // break if no suitable assertion
@@ -284 +305 @@
                 // defer if too many suitable assertions
                 if ( matches.size() > 1 ) {
-                        resn.deferred.emplace_back( assn.decl, assn.info, std::move(matches) );
+                        it->second.deferIds.emplace_back( assn.decl, assn.info );
+                        resn.deferred.emplace_back( cache, assnKey );
                         return true;
                 }
@@ -292 +314 @@
                 addToIndexer( match.have, resn.indexer );
                 resn.newNeed.insert( match.need.begin(), match.need.end() );
-                resn.alt.env = std::move(match.env);
-                resn.alt.openVars = std::move(match.openVars);
+                resn.alt.env = match.env;
+                resn.alt.openVars = match.openVars;
 
                 bindAssertion( assn.decl, assn.info, resn.alt, match, resn.inferred );
@@ -342 +364 @@
         static const int recursionLimit = /* 10 */ 4;
 
-        void resolveAssertions( Alternative& alt, const SymTab::Indexer& indexer, AltList& out, std::list<std::string>& errors ) {
+        void resolveAssertions( Alternative& alt, const SymTab::Indexer& indexer, AltList& out ) {
                 // finish early if no assertions to resolve
                 if ( alt.need.empty() ) {
@@ -354 +376 @@
                 ResnList resns{ ResnState{ alt, root_indexer } };
                 ResnList new_resns{};
+                AssnCache assnCache;
 
                 // resolve assertions in breadth-first-order up to a limited number of levels deep
@@ -362 +385 @@
                                 for ( auto& assn : resn.need ) {
                                         // fail early if any assertion is not resolvable
-                                        if ( ! resolveAssertion( assn, resn ) ) {
-                                                Indenter tabs{ Indenter::tabsize, 3 };
-                                                std::ostringstream ss;
-                                                ss << tabs << "Unsatisfiable alternative:\n";
-                                                resn.alt.print( ss, ++tabs );
-                                                ss << --tabs << "Could not satisfy assertion:\n";
-                                                assn.decl->print( ss, ++tabs );
-                                                
-                                                errors.emplace_back( ss.str() );
-                                                goto nextResn;
-                                        }
+                                        if ( ! resolveAssertion( assn, resn, assnCache ) ) goto nextResn;
                                 }
 
@@ -383 +396 @@
                                         }
                                 } else {
+                                        // only resolve each deferred assertion once
+                                        std::sort( resn.deferred.begin(), resn.deferred.end() );
+                                        auto last = std::unique( resn.deferred.begin(), resn.deferred.end() );
+                                        resn.deferred.erase( last, resn.deferred.end() );
                                         // resolve deferred assertions by mutual compatibility
                                         std::vector<CandidateEnvMerger::OutType> compatible = filterCombos(
                                                 resn.deferred, 
                                                 CandidateEnvMerger{ resn.alt.env, resn.alt.openVars, resn.indexer } );
-                                        // fail early if no mutually-compatible assertion satisfaction
-                                        if ( compatible.empty() ) {
-                                                Indenter tabs{ Indenter::tabsize, 3 };
-                                                std::ostringstream ss;
-                                                ss << tabs << "Unsatisfiable alternative:\n";
-                                                resn.alt.print( ss, ++tabs );
-                                                ss << --tabs << "No mutually-compatible satisfaction for assertions:\n";
-                                                ++tabs;
-                                                for ( const auto& d : resn.deferred ) {
-                                                        d.decl->print( ss, tabs );
-                                                }
-
-                                                errors.emplace_back( ss.str() );
-                                                goto nextResn;
-                                        }
                                         // sort by cost
                                         CandidateCost coster{ resn.indexer };
@@ -427 +429 @@
                                                         new_resn.newNeed.insert( match.need.begin(), match.need.end() );
 
-                                                        bindAssertion( r.decl, r.info, new_resn.alt, match, new_resn.inferred );
+                                                        // for each deferred assertion with the same form
+                                                        for ( AssnId id : r.item.deferIds ) {
+                                                                bindAssertion( 
+                                                                        id.decl, id.info, new_resn.alt, match, new_resn.inferred );
+                                                        }
                                                 }