Merge pull request #4708 from WalterBright/dtsize

Improve small string optimization for dt_t
dlang · Jun 2, 2015 · fc30df5 · fc30df5
1 parent e2136e7
commit fc30df5
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Showing 2 changed files with 5 additions and 4 deletions.
diff --git a/src/backend/cc.h b/src/backend/cc.h
@@ -1597,12 +1597,13 @@ struct dt_t
 {   dt_t *DTnext;                       // next in list
     char dt;                            // type (DTxxxx)
     unsigned char Dty;                  // pointer type
+    unsigned char DTn;                  // DTibytes: number of bytes
     union
     {
         struct                          // DTibytes
-        {   char DTn_;                  // number of bytes
-            #define DTn _DU._DI.DTn_
-            char DTdata_[8];            // data
+        {
+            #define DTibytesMax (sizeof(char *) + sizeof(unsigned) + sizeof(int) + sizeof(targ_size_t))
+            char DTdata_[DTibytesMax];  // data
             #define DTdata _DU._DI.DTdata_
         }_DI;
         targ_size_t DTazeros_;          // DTazeros,DTcommon,DTsymsize

diff --git a/src/backend/dt.c b/src/backend/dt.c
@@ -139,7 +139,7 @@ dt_t ** dtnbytes(dt_t **pdtend,unsigned size,const char *ptr)
         pdtend = &((*pdtend)->DTnext);
     if (size)
     {
-        if (size <= 7)
+        if (size < DTibytesMax)
         {   dt = dt_calloc(DT_ibytes);
             dt->DTn = size;
             memcpy(dt->DTdata,ptr,size);