Import SQLite 3.8.7.4.

third_party/sqlite/src/mkopcodec.awk

 #!/usr/bin/awk -f
 #
 # This AWK script scans the opcodes.h file (which is itself generated by
 # another awk script) and uses the information gleaned to create the
 # opcodes.c source file.
 #
 # Opcodes.c contains strings which are the symbolic names for the various
 # opcodes used by the VDBE.  These strings are used when disassembling a
 # VDBE program during tracing or as a result of the EXPLAIN keyword.
 #
 BEGIN {
   print "/* Automatically generated.  Do not edit */"
   print "/* See the mkopcodec.awk script for details. */"
   printf "#if !defined(SQLITE_OMIT_EXPLAIN)"
-  printf    " || !defined(NDEBUG)"
   printf    " || defined(VDBE_PROFILE)"
   print     " || defined(SQLITE_DEBUG)"
+  print "#if defined(SQLITE_ENABLE_EXPLAIN_COMMENTS) || defined(SQLITE_DEBUG)"
+  print "# define OpHelp(X) \"\\0\" X"
+  print "#else"
+  print "# define OpHelp(X)"
+  print "#endif"
   print "const char *sqlite3OpcodeName(int i){"
   print " static const char *const azName[] = { \"?\","
+  mx = 0
 }
-/define OP_/ {
+/^.define OP_/ {
   sub("OP_","",$2)
-  i++
-  printf "     /* %3d */ \"%s\",\n", $3, $2
+  i = $3+0
+  label[i] = $2
+  if( mx<i ) mx = i
+  for(j=5; j<NF; j++) if( $j=="synopsis:" ) break
+  if( j<NF ){
+    j++
+    x = $j
+    for(j=j+1; j<NF; j++) x = x " " $j
+    synopsis[i] = x
+  }else{
+    synopsis[i] = ""
+  }
 }
 END {
+  for(i=1; i<=mx; i++){
+    printf "     /* %3d */ %-18s OpHelp(\"%s\"),\n", i, \
+        "\"" label[i] "\"", synopsis[i]
+  }
   print "  };"
   print "  return azName[i];"
   print "}"
   print "#endif"
 }