Changes in src/ResolvExpr/Cost.h [cdcddfe1:b10c39a0]

File:

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

src/ResolvExpr/Cost.h

@@ -7 +7 @@
 // Cost.h --
 //
-// Author           : Richard C. Bilson
+// Author           : Peter Buhr and Aaron Moss
 // Created On       : Sun May 17 09:39:50 2015
 // Last Modified By : Peter A. Buhr
-// Last Modified On : Thu Feb  7 20:54:29 2019
-// Update Count     : 8
+// Last Modified On : Mon Apr 29 18:33:44 2019
+// Update Count     : 49
 //
 
@@ -17 +17 @@
 
 #include <iostream>
+#include <cassert>
+#include <climits>
 
 namespace ResolvExpr {
+#if 0
+
+        //*************************** OLD ***************************
+
         class Cost {
           private:
                 Cost( int unsafeCost, int polyCost, int safeCost, int signCost,
-                        int varCost, int specCost, int referenceCost );
+                          int varCost, int specCost, int referenceCost );
           public:
                 Cost & incUnsafe( int inc = 1 );
@@ -71 +77 @@
 
         inline Cost::Cost( int unsafeCost, int polyCost, int safeCost, int signCost,
-                        int varCost, int specCost, int referenceCost )
+                                           int varCost, int specCost, int referenceCost )
                 : unsafeCost( unsafeCost ), polyCost( polyCost ), safeCost( safeCost ), signCost( signCost ),
                   varCost( varCost ), specCost( specCost ), referenceCost( referenceCost ) {}
@@ -121 +127 @@
                 return Cost{
                         unsafeCost + other.unsafeCost, polyCost + other.polyCost, safeCost + other.safeCost,
-                        signCost + other.signCost, varCost + other.varCost, specCost + other.specCost,
-                        referenceCost + other.referenceCost };
+                                signCost + other.signCost, varCost + other.varCost, specCost + other.specCost,
+                                referenceCost + other.referenceCost };
         }
 
@@ -211 +217 @@
                           << cost.referenceCost << " )";
         }
+
+#else
+
+        //*************************** NEW ***************************
+
+        // To maximize performance and space, the 7 resolution costs are packed into a single 64-bit word. However, the
+        // specialization cost is a negative value so a correction is needed is a few places.
+
+        class Cost {
+                union {
+                        struct {
+                        #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+                                // Little-endian => first value is low priority and last is high priority.
+                                unsigned char padding;                                  ///< unused
+                                unsigned char referenceCost;                    ///< reference conversions
+                                unsigned char specCost;                                 ///< Polymorphic type specializations (type assertions), negative cost
+                                unsigned char varCost;                                  ///< Count of polymorphic type variables
+                                unsigned char signCost;                                 ///< Count of safe sign conversions
+                                unsigned char safeCost;                                 ///< Safe (widening) conversions
+                                unsigned char polyCost;                                 ///< Count of parameters and return values bound to some poly type
+                                unsigned char unsafeCost;                               ///< Unsafe (narrowing) conversions
+                        #else
+                                #error Cost BIG_ENDIAN unsupported
+                        #endif
+                        } v;
+                        uint64_t all;
+                };
+                static const unsigned char correctb = 0xff;             // byte correction for negative spec cost
+                static const uint64_t correctw = 0x00'00'00'00'00'ff'00'00; //' word correction for negative spec cost
+          public:
+                // Compiler adjusts constants for correct endian.
+                enum : uint64_t {
+                        zero      = 0x00'00'00'00'00'ff'00'00,
+                        infinity  = 0xff'ff'ff'ff'ff'00'ff'ff,
+                        unsafe    = 0x01'00'00'00'00'ff'00'00,
+                        poly      = 0x00'01'00'00'00'ff'00'00,
+                        safe      = 0x00'00'01'00'00'ff'00'00,
+                        sign      = 0x00'00'00'01'00'ff'00'00,
+                        var       = 0x00'00'00'00'01'ff'00'00,
+                        spec      = 0x00'00'00'00'00'fe'00'00,
+                        reference = 0x00'00'00'00'00'ff'01'00,
+                }; //'
+
+                Cost( uint64_t all ) { Cost::all = all; }
+                Cost( int unsafeCost, int polyCost, int safeCost, int signCost, int varCost, int specCost, int referenceCost ) {
+                        // Assume little-endian => first value is low priority and last is high priority.
+                        v = {
+                        #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+                                (unsigned char)0,                                               // padding
+                                (unsigned char)referenceCost,                   // low priority
+                                (unsigned char)(specCost + correctb),   // correct for signedness
+                                (unsigned char)varCost, 
+                                (unsigned char)signCost, 
+                                (unsigned char)safeCost, 
+                                (unsigned char)polyCost, 
+                                (unsigned char)unsafeCost,                              // high priority
+                        #else
+                                #error Cost BIG_ENDIAN unsupported
+                        #endif
+                        };
+                }
+
+                int get_unsafeCost() const { return v.unsafeCost; }
+                int get_polyCost() const { return v.polyCost; }
+                int get_safeCost() const { return v.safeCost; }
+                int get_signCost() const { return v.signCost; }
+                int get_varCost() const { return v.varCost; }
+                int get_specCost() const { return -(correctb - v.specCost); }
+                int get_referenceCost() const { return v.referenceCost; }
+
+                friend bool operator==( const Cost, const Cost );
+                friend bool operator!=( const Cost lhs, const Cost rhs );
+                // returns negative for *this < rhs, 0 for *this == rhs, positive for *this > rhs
+                int compare( const Cost rhs ) const {
+                        if ( all == infinity ) return 1;
+                        if ( rhs.all == infinity ) return -1;
+                        return all > rhs.all ? 1 : all == rhs.all ? 0 : -1;
+                }
+                friend bool operator<( const Cost lhs, const Cost rhs );
+
+                friend Cost operator+( const Cost lhs, const Cost rhs );
+ 
+                Cost operator+=( const Cost rhs ) {
+                        if ( all == infinity ) return *this;
+                        if ( rhs.all == infinity ) {
+                                all = infinity;
+                                return *this;
+                        }
+                        all += rhs.all - correctw;                                      // correct for negative spec cost
+                        return *this;
+                }
+
+                Cost incUnsafe( int inc = 1 ) {
+                        if ( all != infinity ) { assert( v.unsafeCost + inc <= UCHAR_MAX ); v.unsafeCost += inc; }
+                        return *this;
+                }
+
+                Cost incPoly( int inc = 1 ) {
+                        if ( all != infinity ) { assert( v.polyCost + inc <= UCHAR_MAX ); v.polyCost += inc; }
+                        return *this;
+                }
+
+                Cost incSafe( int inc = 1 ) {
+                        if ( all != infinity ) { assert( v.safeCost + inc <= UCHAR_MAX ); v.safeCost += inc; }
+                        return *this;
+                }
+
+                Cost incSign( int inc = 1 ) {
+                        if ( all != infinity ) { assert( v.signCost + inc <= UCHAR_MAX ); v.signCost += inc; }
+                        return *this;
+                }
+
+                Cost incVar( int inc = 1 ) {
+                        if ( all != infinity ) { assert( v.varCost + inc <= UCHAR_MAX ); v.varCost += inc; }
+                        return *this;
+                }
+
+                Cost decSpec( int dec = 1 ) {
+                        if ( all != infinity ) { assert( v.specCost - dec >= 0 ); v.specCost -= dec; }
+                        return *this;
+                }
+
+                Cost incReference( int inc = 1 ) {
+                        if ( all != infinity ) { assert( v.referenceCost + inc <= UCHAR_MAX ); v.referenceCost += inc; }
+                        return *this;
+                }
+
+                friend std::ostream & operator<<( std::ostream & os, const Cost cost );
+        };
+
+        inline bool operator==( const Cost lhs, const Cost rhs ) {
+                return lhs.all == rhs.all;
+        }
+
+        inline bool operator!=( const Cost lhs, const Cost rhs ) {
+                return !( lhs.all == rhs.all );
+        }
+
+        inline bool operator<( const Cost lhs, const Cost rhs ) {
+                if ( lhs.all == Cost::infinity ) return false;
+                if ( rhs.all == Cost::infinity ) return true;
+                return lhs.all < rhs.all;
+        }
+
+        inline Cost operator+( const Cost lhs, const Cost rhs ) {
+                if ( lhs.all == Cost::infinity || rhs.all == Cost::infinity ) return Cost{ Cost::infinity };
+                return Cost{ lhs.all + rhs.all - Cost::correctw }; // correct for negative spec cost
+        }
+
+        inline std::ostream & operator<<( std::ostream & os, const Cost cost ) {
+                return os << "( " << cost.get_unsafeCost() << ", " << cost.get_polyCost() << ", " << cost.get_safeCost()
+                                  << ", " << cost.get_signCost() << ", " << cost.get_varCost() << ", " << cost.get_specCost()
+                                  << ", " << cost.get_referenceCost() << " )";
+        }
+#endif // 0
 } // namespace ResolvExpr