Add the vdbe-compress.tcl script which automatically refactors the

sqlite3VdbeExec() routine to use less stack space.  Use this script
when constructing the amalgamation. (CVS 6704)

FossilOrigin-Name: 7f43391831b03e53d967acee6ae02089740aaedb

Makefile.in

@@ -488,6 +488,8 @@ sqlite3$(TEXE):	$(TOP)/src/shell.c libsqlite3.la sqlite3.h
 	mkdir -p tsrc
 	cp $(SRC) tsrc
 	rm tsrc/sqlite.h.in tsrc/parse.y
+	$(TCLSH_CMD) $(TOP)/tool/vdbe-compress.tcl <tsrc/vdbe.c >vdbe.new
+	mv vdbe.new tsrc/vdbe.c
 	touch .target_source
 
 sqlite3.c:	.target_source $(TOP)/tool/mksqlite3c.tcl

main.mk

@@ -323,11 +323,13 @@ objects: $(LIBOBJ_ORIG)
 # files are automatically generated.  This target takes care of
 # all that automatic generation.
 #
-target_source:	$(SRC)
+target_source:	$(SRC) $(TOP)/tool/vdbe-compress.tcl
 	rm -rf tsrc
 	mkdir tsrc
 	cp -f $(SRC) tsrc
 	rm tsrc/sqlite.h.in tsrc/parse.y
+	tclsh $(TOP)/tool/vdbe-compress.tcl <tsrc/vdbe.c >vdbe.new
+	mv vdbe.new tsrc/vdbe.c
 	touch target_source
 
 sqlite3.c:	target_source $(TOP)/tool/mksqlite3c.tcl

manifest

@@ -1,7 +1,7 @@
-C Avoid\sallocating\slarge\sobjects\son\sthe\sstack\sin\sthe\sincremental\sBLOB\sI/O\ninterface.\s(CVS\s6703)
-D 2009-06-01T19:53:31
+C Add\sthe\svdbe-compress.tcl\sscript\swhich\sautomatically\srefactors\sthe\nsqlite3VdbeExec()\sroutine\sto\suse\sless\sstack\sspace.\s\sUse\sthis\sscript\nwhen\sconstructing\sthe\samalgamation.\s(CVS\s6704)
+D 2009-06-02T15:21:42
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
-F Makefile.in 583e87706abc3026960ed759aff6371faf84c211
+F Makefile.in 8b8fb7823264331210cddf103831816c286ba446
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
 F Makefile.vxworks 51698ac39a2d114c1586b7694838f2f321c43f64
 F README b974cdc3f9f12b87e851b04e75996d720ebf81ac
@@ -86,7 +86,7 @@ F ext/rtree/tkt3363.test 6662237ea75bb431cd5d262dfc9535e1023315fc
 F ext/rtree/viewrtree.tcl 09526398dae87a5a87c5aac2b3854dbaf8376869
 F install-sh 9d4de14ab9fb0facae2f48780b874848cbf2f895
 F ltmain.sh 3ff0879076df340d2e23ae905484d8c15d5fdea8
-F main.mk 8388687358db061fa98f062f8b417b986d8ff3fe
+F main.mk 4a9e8f062833f7ef6fc926f2701f3ce1c83a3373
 F mkdll.sh 7d09b23c05d56532e9d44a50868eb4b12ff4f74a
 F mkextu.sh 416f9b7089d80e5590a29692c9d9280a10dbad9f
 F mkextw.sh 4123480947681d9b434a5e7b1ee08135abe409ac
@@ -203,7 +203,7 @@ F src/update.c 6ae6c26adff8dc34532d578f66e6cfde04b5d177
 F src/utf.c 9541d28f40441812c0b40f00334372a0542c00ff
 F src/util.c a9719d309f6c65b3b79fa3ca8512fa8e3947a391
 F src/vacuum.c 981686c910b2ff9fe3db814e01da31cf9dbd48c7
-F src/vdbe.c b859cb274024e5755aa03625251ff859e3e95158
+F src/vdbe.c 2f2c4b5a1b92cdbae31f5c5d5a380c697fa3dcc4
 F src/vdbe.h 35a648bc3279a120da24f34d9a25213ec15daf8a
 F src/vdbeInt.h 43183a2a18654fa570219ab65e53a608057c48ae
 F src/vdbeapi.c 86aa27a5f3493aaffb8ac051782aa3b22670d7ed
@@ -731,7 +731,8 @@ F tool/speedtest16.c c8a9c793df96db7e4933f0852abb7a03d48f2e81
 F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
-P c7c0c58e472cd8277b2ad58bb60834190bace4fa
-R 01d40d71e1b5c8cea7b1b21c881c4bd8
+F tool/vdbe-compress.tcl 383f4be3ceb8cec24f31f27480232fbb866fd83a
+P ea7dfde700fb57ed0ecb5000a55abbf45aa1e09d
+R f304b4ea19d83f978fafc25600629030
 U drh
-Z f0ffd7a898768d77c536a218a2488cbe
+Z 613f8e55a41fae0a6bf73d1968f3449f

manifest.uuid

@@ -1 +1 @@
-ea7dfde700fb57ed0ecb5000a55abbf45aa1e09d
+7f43391831b03e53d967acee6ae02089740aaedb

tool/vdbe-compress.tcl

@@ -0,0 +1,124 @@
+#!/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
+#
+# 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
+
+# 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.
+#
+set vlist {}
+set seenDecl 0
+set namechars {abcdefghijklmnopqrstuvwxyz}
+set nnc [string length $namechars]
+while {![eof stdin]} {
+  set line [gets stdin]
+  if {[regexp "^case (OP_\\w+): \173" $line all operator]} {
+    append afterUnion $line\n
+    set vlist {}
+    while {![eof stdin]} {
+      set line [gets stdin]
+      if {[regexp {^ +(const )?\w+ \*?(\w+)(\[.*\])?;} $line \
+           all constKeyword vname notused1]} {
+        if {!$seenDecl} {
+          set sname {}
+          append sname [string index $namechars [expr {$sCtr/$nnc}]]
+          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 $vname
+      } else {
+        break
+      }
+    }
+    if {$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
+    }
+    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