walkero
/
cppcheck
1
0
Fork 0
Code Issues Pull Requests Projects Releases 1 Wiki Activity

Match compiler: Collect and cache plain C-strings 

Profiler runs with gperftools showed we were spending
a lot of time in strlen() even with compiled match patterns.

If you compare a std::string with a plain C-string,
the comparison operator needs to calculate the length
of the C-string via strlen().

We can avoid this by turning all C-strings into C++ strings,
which cache the string length internally.

The match compiler has been adapted to collect all
C-strings during compilation and aggregate them.

Benchmark on the 'rpm' code base on a Core i7 920 box:

cppcheck without matchcompiler:
real    0m30.977s

cppcheck with previous matchcompiler:
real    0m28.157s

cppcheck with cached C-strings:
real    0m17.823s
This commit is contained in:
Thomas Jarosch 2012-12-30 23:05:25 +01:00
parent fe5ee76165
commit 3c915b534d
1 changed files with 33 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

48
tools/matchcompiler.py
View File

@ -3,7 +3,17 @@
import re
import glob
def compileCmd(tok):
def insertMatchStr(matchStrs, look_for):
prefix = 'matchStr'
# Add entry if needed
if look_for not in matchStrs:
pos = len(matchStrs) + 1
matchStrs[look_for] = pos
return prefix + str(matchStrs[look_for])
def compileCmd(tok, matchStrs):
if tok == '%any%':
return 'true'
elif tok == '%bool%':
@ -17,22 +27,23 @@ def compileCmd(tok):
elif tok == '%op%':
return 'tok->isOp()'
elif tok == '%or%':
return '(tok->str()=="|")'
return '(tok->str()==' + insertMatchStr(matchStrs, '|') + ')/* | */'
elif tok == '%oror%':
return '(tok->str()=="||")'
return '(tok->str()==' + insertMatchStr(matchStrs, '||') + ')/* || */'
elif tok == '%str%':
return '(tok->type()==Token::eString)'
elif tok == '%type%':
return '(tok->isName() && tok->varId()==0U && tok->str() != "delete")'
return '(tok->isName() && tok->varId()==0U && tok->str() != ' + insertMatchStr(matchStrs, 'delete') + '/* delete */)'
elif tok == '%var%':
return 'tok->isName()'
elif tok == '%varid%':
return '(tok->isName() && tok->varId()==varid)'
elif (len(tok)>2) and (tok[0]=="%"):
print ("unhandled:" + tok)
return '(tok->str()=="'+tok+'")'
def compilePattern(pattern, nr, varid):
return '(tok->str()==' + insertMatchStr(matchStrs, tok) + ')/* ' + tok + ' */'
def compilePattern(matchStrs, pattern, nr, varid):
arg2 = ''
if varid:
arg2 = ', const unsigned int varid'
@ -76,7 +87,7 @@ def compilePattern(pattern, nr, varid):
if not first:
ret = ret + logicalOp
first = False
ret = ret + neg + compileCmd(tok2)
ret = ret + neg + compileCmd(tok2, matchStrs)
if "" in tokens2:
ret = ret + '))\n'
@ -88,14 +99,15 @@ def compilePattern(pattern, nr, varid):
# !!a
elif tok[0:2]=="!!":
ret = ret + ' if (tok && tok->str() == "' + tok[2:] + '")\n'
ret = ret + ' if (tok && tok->str() == ' + insertMatchStr(matchStrs, tok[2:]) + ')/* ' + tok[2:] + ' */\n'
ret = ret + ' return false;\n'
gotoNextToken = ' tok = tok ? tok->next() : NULL;\n'
else:
ret = ret + ' if (!tok || !' + compileCmd(tok) + ')\n'
ret = ret + ' if (!tok || !' + compileCmd(tok, matchStrs) + ')\n'
ret = ret + ' return false;\n'
ret = ret + ' return true;\n}\n'
return ret
def parseMatch(line, pos1):
@ -137,13 +149,14 @@ def convertFile(srcname, destname):
srclines = fin.readlines()
fin.close()
header = '#include "token.h"\n'
header += '#include "errorlogger.h"\n'
header += '#include <string>\n'
header += '#include <cstring>\n'
matchfunctions = ''
matchfunctions = matchfunctions + '#include "token.h"\n'
matchfunctions = matchfunctions + '#include "errorlogger.h"\n'
matchfunctions = matchfunctions + '#include <string>\n'
matchfunctions = matchfunctions + '#include <cstring>\n'
code = ''
matchStrs = {}
patternNumber = 1
for line in srclines:
while True:
@ -175,13 +188,18 @@ def convertFile(srcname, destname):
if arg3:
a3 = ',' + arg3
line = line[:pos1]+'match'+str(patternNumber)+'('+arg1+a3+')'+line[pos1+len(g0):]
matchfunctions = matchfunctions + compilePattern(arg2, patternNumber, arg3)
matchfunctions = matchfunctions + compilePattern(matchStrs, arg2, patternNumber, arg3)
patternNumber = patternNumber + 1
code = code + line
# Compute string list
stringList = ''
for match in sorted(matchStrs, key=matchStrs.get):
stringList += 'static const std::string matchStr' + str(matchStrs[match]) + '("' + match + '");\n'
fout = open(destname, 'wt')
fout.write(matchfunctions+code)
fout.write(header+stringList+matchfunctions+code)
fout.close()
# selftests..