Import SQLite 3.8.7.4.

third_party/sqlite/src/tool/vdbe-compress.tcl

 #!/usr/bin/tcl
 #
 # This script makes modifications to the vdbe.c source file which reduce
 # the amount of stack space required by the sqlite3VdbeExec() routine.
 #
 # The modifications performed by this script are optional.  The vdbe.c
 # source file will compile correctly with and without the modifications
 # performed by this script.  And all routines within vdbe.c will compute
 # the same result.  The modifications made by this script merely help
 # the C compiler to generate code for sqlite3VdbeExec() that uses less
 # stack space.
 #
 # Script usage:
 #
 #          mv vdbe.c vdbe.c.template
-#          tclsh vdbe-compress.tcl <vdbe.c.template >vdbe.c
+#          tclsh vdbe-compress.tcl $CFLAGS <vdbe.c.template >vdbe.c
 #
 # Modifications made:
 #
 # All modifications are within the sqlite3VdbeExec() function.  The
 # modifications seek to reduce the amount of stack space allocated by
 # this routine by moving local variable declarations out of individual
 # opcode implementations and into a single large union.  The union contains
 # a separate structure for each opcode and that structure contains the
 # local variables used by that opcode.  In this way, the total amount
 # of stack space required by sqlite3VdbeExec() is reduced from the
 # sum of all local variables to the maximum of the local variable space
 # required for any single opcode.
 #
 # In order to be recognized by this script, local variables must appear
 # on the first line after the open curly-brace that begins a new opcode
 # implementation.  Local variables must not have initializers, though they
 # may be commented.
 #
 # The union definition is inserted in place of a special marker comment
 # in the preamble to the sqlite3VdbeExec() implementation.
 #
 #############################################################################
 #
 set beforeUnion {}   ;# C code before union
 set unionDef {}      ;# C code of the union
 set afterUnion {}    ;# C code after the union
 set sCtr 0           ;# Context counter
 
+# If the SQLITE_SMALL_STACK compile-time option is missing, then
+# this transformation becomes a no-op.
+#
+if {![regexp {SQLITE_SMALL_STACK} $argv]} {
+  while {![eof stdin]} {
+    puts [gets stdin]
+  }
+  exit
+}
+
 # Read program text up to the spot where the union should be
 # inserted.
 #
 while {![eof stdin]} {
   set line [gets stdin]
   if {[regexp {INSERT STACK UNION HERE} $line]} break
   append beforeUnion $line\n
 }
 
 # Process the remaining text.  Build up the union definition as we go.
@@ skipping 17 matching lines @@
           append sname [string index $namechars [expr {$sCtr%$nnc}]]
           incr sCtr
           append unionDef "    struct ${operator}_stack_vars \173\n"
           append afterUnion \
              "#if 0  /* local variables moved into u.$sname */\n"
           set seenDecl 1
         }
         append unionDef "    $line\n"
         append afterUnion $line\n
         lappend vlist $vname
+      } elseif {[regexp {^#(if|endif)} $line] && [llength $vlist]>0} {
+        append unionDef "$line\n"
+        append afterUnion $line\n
       } else {
         break
       }
     }
     if {$seenDecl} {
       append unionDef   "    \175 $sname;\n"
       append afterUnion "#endif /* local variables moved into u.$sname */\n"
     }
     set seenDecl 0
   }
   if {[regexp "^\175" $line]} {
     append afterUnion $line\n
     set vlist {}
   } elseif {[llength $vlist]>0} {
     append line " "
     foreach v $vlist {
       regsub -all "(\[^a-zA-Z0-9>.\])${v}(\\W)" $line "\\1u.$sname.$v\\2" line
       regsub -all "(\[^a-zA-Z0-9>.\])${v}(\\W)" $line "\\1u.$sname.$v\\2" line
+
+      # The expressions above fail to catch instance of variable "abc" in
+      # expressions like (32>abc). The following expression makes those
+      # substitutions.
+      regsub -all "(\[^-\])>${v}(\\W)" $line "\\1>u.$sname.$v\\2" line
     }
     append afterUnion [string trimright $line]\n
   } elseif {$line=="" && [eof stdin]} {
     # no-op
   } else {
     append afterUnion $line\n
   }
 }
 
 # Output the resulting text.
 #
 puts -nonewline $beforeUnion
 puts "  /********************************************************************"
 puts "  ** Automatically generated code"
 puts "  **"
 puts "  ** The following union is automatically generated by the"
 puts "  ** vdbe-compress.tcl script.  The purpose of this union is to"
 puts "  ** reduce the amount of stack space required by this function."
 puts "  ** See comments in the vdbe-compress.tcl script for details."
 puts "  */"
 puts "  union vdbeExecUnion \173"
 puts -nonewline $unionDef
 puts "  \175 u;"
 puts "  /* End automatically generated code"
 puts "  ********************************************************************/"
 puts -nonewline $afterUnion