Changeset 9ad2f9f for src/ResolvExpr/TypeEnvironment.h

Timestamp:

Oct 3, 2018, 5:08:14 PM (6 years ago)

Author:

Aaron Moss <a3moss@…>

Branches:

ADT, aaron-thesis, arm-eh, ast-experimental, cleanup-dtors, deferred_resn, enum, forall-pointer-decay, jacob/cs343-translation, jenkins-sandbox, master, new-ast, new-ast-unique-expr, no_list, persistent-indexer, pthread-emulation, qualifiedEnum

Children:

59cf83b

Parents:

588c2b0

Message:

TypeEnvironment::combine -- compiles, untested

File:

• src/ResolvExpr/TypeEnvironment.h (modified) (5 diffs)

src/ResolvExpr/TypeEnvironment.h

@@ -39 +39 @@
         // declarations.
         //
-        // I've seen a TU go from 54 minutes to 1 minute 34 seconds with the addition of this comparator.
+        // I've seen a TU go from 54 minutes to 1 minute 34 seconds with the addition of this 
+        // comparator.
         //
         // Note: since this compares pointers for position, minor changes in the source file that affect
         // memory layout can alter compilation time in unpredictable ways. For example, the placement
         // of a line directive can reorder type pointers with respect to each other so that assertions
-        // are seen in different orders, causing a potentially different number of unification calls when
-        // resolving assertions. I've seen a TU go from 36 seconds to 27 seconds by reordering line directives
-        // alone, so it would be nice to fix this comparison so that assertions compare more consistently.
-        // I've tried to modify this to compare on mangle name instead of type as the second comparator, but
-        // this causes some assertions to never be recorded. More investigation is needed.
+        // are seen in different orders, causing a potentially different number of unification calls 
+        // when resolving assertions. I've seen a TU go from 36 seconds to 27 seconds by reordering 
+        // line directives alone, so it would be nice to fix this comparison so that assertions compare 
+        // more consistently. I've tried to modify this to compare on mangle name instead of type as 
+        // the second comparator, but this causes some assertions to never be recorded. More 
+        // investigation is needed.
         struct AssertCompare {
                 bool operator()( DeclarationWithType * d1, DeclarationWithType * d2 ) const {
@@ -58 +60 @@
         struct AssertionSetValue {
                 bool isUsed;
-                // chain of Unique IDs of the assertion declarations. The first ID in the chain is the ID of an assertion on the current type,
-                // with each successive ID being the ID of an assertion pulled in by the previous ID. The last ID in the chain is
-                // the ID of the assertion that pulled in the current assertion.
+                // chain of Unique IDs of the assertion declarations. The first ID in the chain is the ID 
+                // of an assertion on the current type, with each successive ID being the ID of an 
+                // assertion pulled in by the previous ID. The last ID in the chain is the ID of the 
+                // assertion that pulled in the current assertion.
                 std::list< UniqueId > idChain;
         };
@@ -91 +94 @@
 
         class TypeEnvironment {
+                using ClassList = std::list< EqvClass >;
           public:
                 const EqvClass* lookup( const std::string &var ) const;
@@ -103 +107 @@
                 bool isEmpty() const { return env.empty(); }
                 void print( std::ostream &os, Indenter indent = {} ) const;
-                // void combine( const TypeEnvironment &second, Type *(*combineFunc)( Type*, Type* ) );
+                
+                /// Simply concatenate the second environment onto this one; no safety checks performed
                 void simpleCombine( const TypeEnvironment &second );
+
+          private:
+                /// Unifies the type bound of to with the type bound of from, returning false if fails
+                bool mergeBound( EqvClass& to, const EqvClass& from, OpenVarSet& openVars, const SymTab::Indexer& indexer );
+
+                /// Merges two type classes from local environment, returning false if fails
+                bool mergeClasses( ClassList::iterator to, ClassList::iterator from, OpenVarSet& openVars, const SymTab::Indexer& indexer );
+
+          public:
+                /// Merges the second environment with this one, checking compatibility.
+                /// Returns false if fails, but does NOT roll back partial changes.
+                bool combine( const TypeEnvironment& second, OpenVarSet& openVars, const SymTab::Indexer& indexer );
+                
                 void extractOpenVars( OpenVarSet &openVars ) const;
                 TypeEnvironment *clone() const { return new TypeEnvironment( *this ); }
@@ -123 +141 @@
                 void forbidWidening();
 
-                using iterator = std::list< EqvClass >::const_iterator;
+                using iterator = ClassList::const_iterator;
                 iterator begin() const { return env.begin(); }
                 iterator end() const { return env.end(); }
 
           private:
-                std::list< EqvClass > env;
+                ClassList env;
                 
-                std::list< EqvClass >::iterator internal_lookup( const std::string &var );
+                ClassList::iterator internal_lookup( const std::string &var );
         };