Add the stack_usage.tcl script for analyzing the output of objdump on the

amalgamation and estimating the sizes of stack frames on each function.

FossilOrigin-Name: 030013ff0c7af5f146a64f9ede31297ff003e0c4

tool/stack_usage.tcl

@@ -0,0 +1,98 @@
+#!/usr/bin/tclsh
+#
+# Parse the output of 
+#
+#         objdump -d sqlite3.o
+#
+# for x64 and generate a report showing:
+#
+#    (1)  Stack used by each function
+#    (2)  Recursion paths and their aggregate stack depth
+#
+set getStack 0
+while {![eof stdin]} {
+  set line [gets stdin]
+  if {[regexp {^[0-9a-f]+ <([^>]+)>:\s*$} $line all procname]} {
+    set curfunc $procname
+    set root($curfunc) 1
+    set calls($curfunc) {}
+    set calledby($curfunc) {}
+    set recursive($curfunc) {}
+    set stkdepth($curfunc) 0
+    set getStack 1
+    continue
+  }
+  if {[regexp {callq? +[0-9a-z]+ <([^>]+)>} $line all other]} {
+    set key [list $curfunc $other]
+    set callpair($key) 1
+    unset -nocomplain root($curfunc)
+    continue
+  }
+  if {[regexp {sub +\$(0x[0-9a-z]+),%[er]sp} $line all xdepth]} {
+    if {$getStack} {
+      scan $xdepth %x depth
+      set stkdepth($curfunc) $depth
+      set getStack 0
+    }
+    continue
+  }
+}
+
+puts "****************** Stack Usage By Function ********************"
+set sdlist {}
+foreach f [array names stkdepth] {
+  lappend sdlist [list $stkdepth($f) $f]
+}
+foreach sd [lsort -integer -decr -index 0 $sdlist] {
+  foreach {depth fname} $sd break
+  puts [format {%6d %s} $depth $fname]
+}
+
+puts "****************** Stack Usage By Recursion *******************"
+foreach key [array names callpair] {
+  foreach {from to} $key break
+  lappend calls($from) $to
+  # lappend calledby($to) $from
+}
+proc all_descendents {root} {
+  global calls recursive
+  set todo($root) $root
+  set go 1
+  while {$go} {
+    set go 0
+    foreach f [array names todo] {
+      set path $todo($f)
+      unset todo($f)
+      if {![info exists calls($f)]} continue
+      foreach x $calls($f) {
+        if {$x==$root} {
+          lappend recursive($root) [concat $path $root]
+        } elseif {![info exists d($x)]} {
+          set go 1
+          set todo($x) [concat $path $x]
+          set d($x) 1
+        }
+      }
+    }
+  }
+  return [array names d]
+}
+set pathlist {}
+foreach f [array names recursive] {
+  all_descendents $f
+  foreach m $recursive($f) {
+    set depth 0
+    foreach b [lrange $m 0 end-1] {
+      set depth [expr {$depth+$stkdepth($b)}]
+    }
+    lappend pathlist [list $depth $m]
+  }
+}
+foreach path [lsort -integer -decr -index 0 $pathlist] {
+  foreach {depth m} $path break
+  set first [lindex $m 0]
+  puts [format {%6d %s %d} $depth $first $stkdepth($first)]
+  foreach b [lrange $m 1 end] {
+    puts "          $b $stkdepth($b)"
+  }
+}