sqlite/mkopcodeh.awk
drh daa28ff326 Fix a problem with the automatic generation of the opcode name table. (CVS 2163)
FossilOrigin-Name: 9eefabc92d3924bcaa2ae0f425fe5635824c64ec
2004-12-10 17:17:18 +00:00

73 lines
2.1 KiB
Awk

#!/usr/bin/awk -f
#
# Generate the file opcodes.h.
#
# This AWK script scans a concatenation of the parse.h output file from the
# parser and the vdbe.c source file in order to generate the opcodes numbers
# for all opcodes.
#
# The lines of the vdbe.c that we are interested in are of the form:
#
# case OP_aaaa: /* same as TK_bbbbb */
#
# The TK_ comment is optional. If it is present, then the value assigned to
# the OP_ is the same as the TK_ value. If missing, the OP_ value is assigned
# a small integer that is different from every other OP_ value.
#
# We go to the trouble of making some OP_ value the same as TK_ values
# as an optimization. During parsing, things like expression operators
# are coded with TK_ values such as TK_ADD, TK_DIVIDE, and so forth. Later
# during code generation, we need to generate corresponding opcodes like
# OP_Add and OP_Divide. By making TK_ADD==OP_Add and TK_DIVIDE==OP_Divide,
# code to translation from one to the other is avoided. This makes the
# code generator run (infinitesimally) faster and more importantly it makes
# the total library smaller.
#
# Remember the TK_ values from the parse.h file
/^#define TK_/ {
tk[$2] = $3
}
# Scan for "case OP_aaaa:" lines in the vdbe.c file
/^case OP_/ {
name = $2
gsub(/:/,"",name)
gsub("\r","",name)
op[name] = -1
for(i=3; i<NF-2; i++){
if($i=="same" && $(i+1)=="as"){
op[name] = tk[$(i+2)]
used[op[name]] = 1
}
}
}
# Assign numbers to all opcodes and output the result.
END {
cnt = 0
max = 0
print "/* Automatically generated. Do not edit */"
print "/* See the mkopcodeh.awk script for details */"
for(name in op){
if( op[name]<0 ){
cnt++
while( used[cnt] ) cnt++
op[name] = cnt
}
used[op[name]] = 1;
if( op[name]>max ) max = op[name]
printf "#define %-30s %d\n", name, op[name]
}
seenUnused = 0;
for(i=1; i<max; i++){
if( !used[i] ){
if( !seenUnused ){
printf "\n/* The following opcode values are never used */\n"
seenUnused = 1
}
printf "/*#define OP_? %d -- Not Used */\n", i
}
}
}