From 7adb34810ee142a7f104584a83765fcb73ba4427 Mon Sep 17 00:00:00 2001
From: Walter Bright <walter@walterbright.com>
Date: Mon, 1 Jun 2015 18:42:21 -0700
Subject: [PATCH] use pools for dt_t and code allocation

---
 src/backend/code.c | 43 ++++++++++++++++++++++++------------
 src/backend/dt.c   | 54 +++++++++++++++++++++++++++++-----------------
 2 files changed, 63 insertions(+), 34 deletions(-)

diff --git a/src/backend/code.c b/src/backend/code.c
index 46372f076d9c..1733099391e4 100644
--- a/src/backend/code.c
+++ b/src/backend/code.c
@@ -1,5 +1,5 @@
 // Copyright (C) 1987-1998 by Symantec
-// Copyright (C) 2000-2013 by Digital Mars
+// Copyright (C) 2000-2015 by Digital Mars
 // All Rights Reserved
 // http://www.digitalmars.com
 // Written by Walter Bright
@@ -30,11 +30,20 @@ code *code_calloc()
 {
     //printf("code %d\n", sizeof(code));
     code *c = code_list;
-    if (c)
-        code_list = code_next(c);
-    else
-        c = (code *)mem_fmalloc(sizeof(*c));
+    if (!c)
+    {
+        const size_t n = 4096 / sizeof(*c);
+        code *chunk = (code *)mem_fmalloc(n * sizeof(code));
+        for (size_t i = 0; i < n - 1; ++i)
+        {
+            code_next(&chunk[i]) = &chunk[i + 1];
+        }
+        code_next(&chunk[n - 1]) = NULL;
+        code_list = chunk;
+        c = chunk;
+    }
 
+    code_list = code_next(c);
     MEMCLEAR(c, sizeof(*c));
 
     //dbg_printf("code_calloc: %p\n",c);
@@ -47,18 +56,24 @@ code *code_calloc()
  */
 
 void code_free(code *cstart)
-{   code **pc;
-    code *c;
-
-    for (pc = &cstart; (c = *pc) != NULL; pc = &code_next(c))
+{
+    if (cstart)
     {
-        if (c->Iop == ASM)
+        code *c = cstart;
+        while (1)
         {
-            mem_free(c->IEV1.as.bytes);
+            if (c->Iop == ASM)
+            {
+                mem_free(c->IEV1.as.bytes);
+            }
+            code *cnext = code_next(c);
+            if (!cnext)
+                break;
+            c = cnext;
         }
+        code_next(c) = code_list;
+        code_list = cstart;
     }
-    *pc = code_list;
-    code_list = cstart;
 }
 
 /*****************
@@ -73,7 +88,7 @@ void code_term()
 
     while (code_list)
     {   cn = code_next(code_list);
-        mem_ffree(code_list);
+        //mem_ffree(code_list);
         code_list = cn;
         count++;
     }
diff --git a/src/backend/dt.c b/src/backend/dt.c
index d0f3973cc5b5..2a0d7d8ebc86 100644
--- a/src/backend/dt.c
+++ b/src/backend/dt.c
@@ -1,5 +1,5 @@
 // Copyright (C) 1984-1998 by Symantec
-// Copyright (C) 2000-2013 by Digital Mars
+// Copyright (C) 2000-2015 by Digital Mars
 // All Rights Reserved
 // http://www.digitalmars.com
 // Written by Walter Bright
@@ -33,17 +33,25 @@ static dt_t *dt_freelist;
 
 static dt_t *dt_calloc(int dtx)
 {
-    dt_t *dt;
-    static dt_t dtzero;
-
-    if (dt_freelist)
+    dt_t *dt = dt_freelist;
+    if (!dt)
     {
-        dt = dt_freelist;
-        dt_freelist = dt->DTnext;
-        *dt = dtzero;
+        const size_t n = 4096 / sizeof(dt_t);
+        dt_t *chunk = (dt_t *)mem_fmalloc(n * sizeof(dt_t));
+        for (size_t i = 0; i < n - 1; ++i)
+        {
+            chunk[i].DTnext = &chunk[i + 1];
+        }
+        chunk[n - 1].DTnext = NULL;
+        dt_freelist = chunk;
+        dt = chunk;
     }
-    else
-        dt = (dt_t *) mem_fcalloc(sizeof(dt_t));
+
+    dt_freelist = dt->DTnext;
+#ifdef DEBUG
+    memset(dt, 0xBE, sizeof(*dt));
+#endif
+    dt->DTnext = NULL;
     dt->dt = dtx;
     return dt;
 }
@@ -53,19 +61,25 @@ static dt_t *dt_calloc(int dtx)
  */
 
 void dt_free(dt_t *dt)
-{   dt_t *dtn;
-
-    for (; dt; dt = dtn)
+{
+    if (dt)
     {
-        switch (dt->dt)
+        dt_t *dtn = dt;
+        while (1)
         {
-            case DT_abytes:
-            case DT_nbytes:
-                mem_free(dt->DTpbytes);
+            switch (dtn->dt)
+            {
+                case DT_abytes:
+                case DT_nbytes:
+                    mem_free(dtn->DTpbytes);
+                    break;
+            }
+            dt_t *dtnext = dtn->DTnext;
+            if (!dtnext)
                 break;
+            dtn = dtnext;
         }
-        dtn = dt->DTnext;
-        dt->DTnext = dt_freelist;
+        dtn->DTnext = dt_freelist;
         dt_freelist = dt;
     }
 }
@@ -76,7 +90,7 @@ void dt_free(dt_t *dt)
 
 void dt_term()
 {
-#if TERMCODE
+#if 0 && TERMCODE
     dt_t *dtn;
 
     while (dt_freelist)