Index: src/main.c
==================================================================
--- src/main.c
+++ src/main.c
@@ -349,11 +349,11 @@
   /*
   ** Zero, unlock, and free the saved database encryption key now.
   */
   db_unsave_encryption_key();
 #endif
-#if defined(_WIN32) || defined(__BIONIC__) && !defined(FOSSIL_HAVE_GETPASS)
+#if defined(_WIN32) || (defined(__BIONIC__) && !defined(FOSSIL_HAVE_GETPASS))
   /*
   ** Free the secure getpass() buffer now.
   */
   freepass();
 #endif
@@ -388,10 +388,17 @@
   */
   if( fossil_getenv("TH1_DELETE_INTERP")!=0 ){
     if( g.interp ){
       Th_DeleteInterp(g.interp); g.interp = 0;
     }
+#if defined(TH_MEMDEBUG)
+    if( Th_GetOutstandingMalloc()!=0 ){
+      fossil_print("Th_GetOutstandingMalloc() => %d\n",
+                   Th_GetOutstandingMalloc());
+    }
+    assert( Th_GetOutstandingMalloc()==0 );
+#endif
   }
 }
 
 /*
 ** Convert all arguments from mbcs (or unicode) to UTF-8. Then

Index: src/makemake.tcl
==================================================================
--- src/makemake.tcl
+++ src/makemake.tcl
@@ -1478,11 +1478,11 @@
 OBJDIR  = $(T)
 OX      = $(OBJDIR)
 O       = .obj
 E       = .exe
 P       = .pdb
-OPTLEVEL= /Os
+DBGOPTS = /Od
 
 INSTALLDIR = .
 !ifdef DESTDIR
 INSTALLDIR = $(DESTDIR)\$(INSTALLDIR)
 !endif
@@ -1501,10 +1501,15 @@
 # Perl is only necessary if OpenSSL support is enabled and it is built from
 # source code.  The PERLDIR environment variable, if it exists, should point
 # to the directory containing the main Perl executable specified here (i.e.
 # "perl.exe").
 PERL    = perl.exe
+
+# Enable use of available compiler optimizations?
+!ifndef OPTIMIZATIONS
+OPTIMIZATIONS = 2
+!endif
 
 # Enable debugging symbols?
 !ifndef DEBUG
 DEBUG = 0
 !endif
@@ -1673,16 +1678,28 @@
 CRTFLAGS = /MTd
 !else
 CRTFLAGS = /MT
 !endif
 !endif
+
+!if $(OPTIMIZATIONS)>3
+RELOPTS = /Os
+!elseif $(OPTIMIZATIONS)>2
+RELOPTS = /Ox
+!elseif $(OPTIMIZATIONS)>1
+RELOPTS = /O2
+!elseif $(OPTIMIZATIONS)>0
+RELOPTS = /O1
+!else
+RELOPTS =
+!endif
 
 !if $(DEBUG)!=0
-CFLAGS    = $(CFLAGS) /Zi $(CRTFLAGS) /Od /DFOSSIL_DEBUG
+CFLAGS    = $(CFLAGS) /Zi $(CRTFLAGS) $(DBGOPTS) /DFOSSIL_DEBUG /DTH_MEMDEBUG
 LDFLAGS   = $(LDFLAGS) /DEBUG
 !else
-CFLAGS    = $(CFLAGS) $(CRTFLAGS) $(OPTLEVEL)
+CFLAGS    = $(CFLAGS) $(CRTFLAGS) $(RELOPTS)
 !endif
 
 BCC       = $(CC) $(CFLAGS)
 TCC       = $(CC) /c $(CFLAGS) $(MSCDEF) $(INCL)
 RCC       = $(RC) /D_WIN32 /D_MSC_VER $(MSCDEF) $(INCL)

Index: src/printf.c
==================================================================
--- src/printf.c
+++ src/printf.c
@@ -1100,11 +1100,11 @@
     /*
     ** Avoid calling into the JSON support subsystem if it
     ** has not yet been initialized, e.g. early SQLite log
     ** messages, etc.
     */
-    assert(json_is_bootstrapped_early());
+    if( !json_is_bootstrapped_early() ) json_bootstrap_early();
     json_err( 0, z, 1 );
     if( g.isHTTP && !g.json.preserveRc ){
       rc = 0 /* avoid HTTP 500 */;
     }
     if( g.cgiOutput==1 ){
@@ -1230,11 +1230,11 @@
     /*
     ** Avoid calling into the JSON support subsystem if it
     ** has not yet been initialized, e.g. early SQLite log
     ** messages, etc.
     */
-    assert(json_is_bootstrapped_early());
+    if( !json_is_bootstrapped_early() ) json_bootstrap_early();
     json_warn( FSL_JSON_W_UNKNOWN, "%s", z );
   }else
 #endif
   {
     if( g.cgiOutput==1 ){

Index: src/th.c
==================================================================
--- src/th.c
+++ src/th.c
@@ -222,11 +222,20 @@
   Buffer *pBuffer,
   const char *zAdd,
   int nAdd
 ){
   int nNew = (pBuffer->nBuf+nAdd)*2+32;
+#if defined(TH_MEMDEBUG)
+  char *zNew = (char *)Th_Malloc(interp, nNew);
+  th_memcpy(zNew, pBuffer->zBuf, pBuffer->nBuf);
+  Th_Free(interp, pBuffer->zBuf);
+  pBuffer->zBuf = zNew;
+#else
+  int nOld = pBuffer->nBufAlloc;
   pBuffer->zBuf = Th_Realloc(interp, pBuffer->zBuf, nNew);
+  memset(pBuffer->zBuf+nOld, 0, nNew-nOld);
+#endif
   pBuffer->nBufAlloc = nNew;
   th_memcpy(&pBuffer->zBuf[pBuffer->nBuf], zAdd, nAdd);
   pBuffer->nBuf += nAdd;
 }
 static void thBufferWriteFast(
@@ -1535,10 +1544,37 @@
   }else{
     return (char *)Th_Malloc(pInterp, 1);
   }
 }
 
+#if defined(TH_MEMDEBUG)
+/*
+** Wrappers around the supplied malloc() and free()
+*/
+void *Th_DbgMalloc(Th_Interp *pInterp, int nByte){
+  void *p;
+  Th_Vtab *pVtab = pInterp->pVtab;
+  if( pVtab ){
+    p = pVtab->xMalloc(nByte);
+    if( p ) memset(p, 0, nByte);
+  }else{
+    p = Th_SysMalloc(pInterp, nByte);
+  }
+  return p;
+}
+void Th_DbgFree(Th_Interp *pInterp, void *z){
+  if( z ){
+    Th_Vtab *pVtab = pInterp->pVtab;
+    if( pVtab ){
+      pVtab->xFree(z);
+    }else{
+      Th_SysFree(pInterp, z);
+    }
+  }
+}
+#endif
+
 /*
 ** Install a new th1 command.
 **
 ** If a command of the same name already exists, it is deleted automatically.
 */
@@ -1821,16 +1857,24 @@
 }
 
 /*
 ** Create a new interpreter.
 */
-Th_Interp * Th_CreateInterp(void){
+Th_Interp * Th_CreateInterp(Th_Vtab *pVtab){
+  int nByte = sizeof(Th_Interp) + sizeof(Th_Frame);
   Th_Interp *p;
 
   /* Allocate and initialise the interpreter and the global frame */
-  p = Th_Malloc(0, sizeof(Th_Interp) + sizeof(Th_Frame));
-  memset(p, 0, sizeof(Th_Interp));
+#if defined(TH_MEMDEBUG)
+  if( pVtab ){
+    p = pVtab->xMalloc(nByte);
+    memset(p, 0, nByte);
+    p->pVtab = pVtab;
+  }else
+#endif
+  p = Th_SysMalloc(0, nByte);
+
   p->paCmd = Th_HashNew(p);
   thPushFrame(p, (Th_Frame *)&p[1]);
   thInitialize(p);
 
   return p;

Index: src/th.h
==================================================================
--- src/th.h
+++ src/th.h
@@ -21,11 +21,11 @@
 typedef struct Th_Interp Th_Interp;
 
 /*
 ** Create and delete interpreters.
 */
-Th_Interp * Th_CreateInterp(void);
+Th_Interp * Th_CreateInterp(Th_Vtab *);
 void Th_DeleteInterp(Th_Interp *);
 
 /*
 ** Evaluate an TH program in the stack frame identified by parameter
 ** iFrame, according to the following rules:
@@ -121,16 +121,31 @@
 
 /*
 ** Access the memory management functions associated with the specified
 ** interpreter.
 */
+#if defined(TH_MEMDEBUG)
+void *Th_DbgMalloc(Th_Interp *, int);
+void Th_DbgFree(Th_Interp *, void *);
+#endif
+
 void *fossil_malloc_zero(size_t);
-void *fossil_realloc(void*,size_t);
-void fossil_free(void*);
-#define Th_Malloc(I,N)     fossil_malloc_zero(N)
-#define Th_Realloc(I,P,N)  fossil_realloc(P,N)
-#define Th_Free(I,P)       fossil_free(P)
+void *fossil_realloc(void *, size_t);
+void fossil_free(void *);
+
+#define Th_SysMalloc(I,N)     fossil_malloc_zero((N))
+#define Th_SysRealloc(I,P,N)  fossil_realloc((P),(N))
+#define Th_SysFree(I,P)       fossil_free((P))
+
+#if defined(TH_MEMDEBUG)
+#  define Th_Malloc(I,N)      Th_DbgMalloc((I),(N))
+#  define Th_Free(I,P)        Th_DbgFree((I),(P))
+#else
+#  define Th_Malloc(I,N)      Th_SysMalloc((I),(N))
+#  define Th_Realloc(I,P,N)   Th_SysRealloc((I),(P),(N))
+#  define Th_Free(I,P)        Th_SysFree((I),(P))
+#endif
 
 /*
 ** Functions for handling TH lists.
 */
 int Th_ListAppend(Th_Interp *, char **, int *, const char *, int);

Index: src/th_main.c
==================================================================
--- src/th_main.c
+++ src/th_main.c
@@ -68,10 +68,46 @@
 ** configuration ("user") database are currently open.
 */
 #define Th_IsRepositoryOpen()     (g.repositoryOpen)
 #define Th_IsConfigOpen()         (g.zConfigDbName!=0)
 
+/*
+** When memory debugging is enabled, use our custom memory allocator.
+*/
+#if defined(TH_MEMDEBUG)
+/*
+** Global variable counting the number of outstanding calls to malloc()
+** made by the th1 implementation. This is used to catch memory leaks
+** in the interpreter. Obviously, it also means th1 is not threadsafe.
+*/
+static int nOutstandingMalloc = 0;
+
+/*
+** Implementations of malloc() and free() to pass to the interpreter.
+*/
+static void *xMalloc(unsigned int n){
+  void *p = fossil_malloc(n);
+  if( p ){
+    nOutstandingMalloc++;
+  }
+  return p;
+}
+static void xFree(void *p){
+  if( p ){
+    nOutstandingMalloc--;
+  }
+  free(p);
+}
+static Th_Vtab vtab = { xMalloc, xFree };
+
+/*
+** Returns the number of outstanding TH1 memory allocations.
+*/
+int Th_GetOutstandingMalloc(){
+  return nOutstandingMalloc;
+}
+#endif
 
 /*
 ** Generate a TH1 trace message if debugging is enabled.
 */
 void Th_Trace(const char *zFormat, ...){
@@ -350,11 +386,11 @@
   if(0==pOut && pThOut!=0){
     pOut = pThOut;
   }
   if(TH_INIT_NO_ENCODE & g.th1Flags){
     encode = 0;
-  }     
+  }
   if( enableOutput && n ){
     if( n<0 ) n = strlen(z);
     if( encode ){
       z = htmlize(z, n);
       n = strlen(z);
@@ -627,10 +663,11 @@
   blob_zero(&title); blob_zero(&body);
   markdown_to_html(&src, &title, &body);
   Th_ListAppend(interp, &zValue, &nValue, blob_str(&title), blob_size(&title));
   Th_ListAppend(interp, &zValue, &nValue, blob_str(&body), blob_size(&body));
   Th_SetResult(interp, zValue, nValue);
+  Th_Free(interp, zValue);
   return TH_OK;
 }
 
 /*
 ** TH1 command: decorate STRING
@@ -810,15 +847,15 @@
     }else if( azCap[i][0]=='*' ){
       rc = 1;
     }else{
       rc = login_has_capability(azCap[i], anCap[i], 0);
     }
-    break;   
+    break;
   }
   Th_Free(interp, azCap);
   Th_SetResultInt(interp, rc);
-  return TH_OK; 
+  return TH_OK;
 }
 
 
 /*
 ** TH1 command: searchable STRING...
@@ -2356,11 +2393,20 @@
   }
   if( forceReset || forceTcl || g.interp==0 ){
     int created = 0;
     int i;
     if( g.interp==0 ){
-      g.interp = Th_CreateInterp();
+      Th_Vtab *pVtab = 0;
+#if defined(TH_MEMDEBUG)
+      if( fossil_getenv("TH1_DELETE_INTERP")!=0 ){
+        pVtab = &vtab;
+        if( g.thTrace ){
+          Th_Trace("th1-init MEMDEBUG ENABLED<br />\n");
+        }
+      }
+#endif
+      g.interp = Th_CreateInterp(pVtab);
       created = 1;
     }
     if( forceReset || created ){
       th_register_language(g.interp);     /* Basic scripting commands. */
     }

Index: src/user.c
==================================================================
--- src/user.c
+++ src/user.c
@@ -38,11 +38,11 @@
     if( z[i]>0 && z[i]<' ' ) z[i] = ' ';
   }
   blob_append(pBlob, z, -1);
 }
 
-#if defined(_WIN32) || defined(__BIONIC__) && !defined(FOSSIL_HAVE_GETPASS)
+#if defined(_WIN32) || (defined(__BIONIC__) && !defined(FOSSIL_HAVE_GETPASS))
 #ifdef _WIN32
 #include <conio.h>
 #endif
 
 /*

Index: win/Makefile.msc
==================================================================
--- win/Makefile.msc
+++ win/Makefile.msc
@@ -14,11 +14,11 @@
 OBJDIR  = $(T)
 OX      = $(OBJDIR)
 O       = .obj
 E       = .exe
 P       = .pdb
-OPTLEVEL= /Os
+DBGOPTS = /Od
 
 INSTALLDIR = .
 !ifdef DESTDIR
 INSTALLDIR = $(DESTDIR)\$(INSTALLDIR)
 !endif
@@ -37,10 +37,15 @@
 # Perl is only necessary if OpenSSL support is enabled and it is built from
 # source code.  The PERLDIR environment variable, if it exists, should point
 # to the directory containing the main Perl executable specified here (i.e.
 # "perl.exe").
 PERL    = perl.exe
+
+# Enable use of available compiler optimizations?
+!ifndef OPTIMIZATIONS
+OPTIMIZATIONS = 2
+!endif
 
 # Enable debugging symbols?
 !ifndef DEBUG
 DEBUG = 0
 !endif
@@ -209,16 +214,28 @@
 CRTFLAGS = /MTd
 !else
 CRTFLAGS = /MT
 !endif
 !endif
+
+!if $(OPTIMIZATIONS)>3
+RELOPTS = /Os
+!elseif $(OPTIMIZATIONS)>2
+RELOPTS = /Ox
+!elseif $(OPTIMIZATIONS)>1
+RELOPTS = /O2
+!elseif $(OPTIMIZATIONS)>0
+RELOPTS = /O1
+!else
+RELOPTS =
+!endif
 
 !if $(DEBUG)!=0
-CFLAGS    = $(CFLAGS) /Zi $(CRTFLAGS) /Od /DFOSSIL_DEBUG
+CFLAGS    = $(CFLAGS) /Zi $(CRTFLAGS) $(DBGOPTS) /DFOSSIL_DEBUG /DTH_MEMDEBUG
 LDFLAGS   = $(LDFLAGS) /DEBUG
 !else
-CFLAGS    = $(CFLAGS) $(CRTFLAGS) $(OPTLEVEL)
+CFLAGS    = $(CFLAGS) $(CRTFLAGS) $(RELOPTS)
 !endif
 
 BCC       = $(CC) $(CFLAGS)
 TCC       = $(CC) /c $(CFLAGS) $(MSCDEF) $(INCL)
 RCC       = $(RC) /D_WIN32 /D_MSC_VER $(MSCDEF) $(INCL)