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// -*- C++ -*-
// Copyright (C) 2012-2013 Red Hat Inc.
//
// This file is part of systemtap, and is free software. You can
// redistribute it and/or modify it under the terms of the GNU General
// Public License (GPL); either version 2, or (at your option) any
// later version.
//
// ---
//
// This file incorporates code from the re2c project; please see
// the file README.stapregex for details.
#include "util.h"
#include "translator-output.h"
#include "session.h"
#include "staptree.h" // needed to use semantic_error
#include <iostream>
#include <cstdlib>
#include <string>
#include <algorithm>
using namespace std;
#include "stapregex-parse.h"
#include "stapregex-tree.h"
#include "stapregex-dfa.h"
#include "stapregex.h"
using namespace stapregex;
// ------------------------------------------------------------------------
stapdfa *
regex_to_stapdfa (systemtap_session *s, const string& input, const token *tok)
{
// Tags are disabled when not used, for the extra bit of efficiency.
// bool do_tag = true; // <- XXX: use to temporarily force tag calculation
bool do_tag = s->need_tagged_dfa;
if (s->dfas.find(input) != s->dfas.end())
return s->dfas[input];
stapdfa *dfa = new stapdfa ("__stp_dfa" + lex_cast(s->dfa_counter++), input, tok, true, do_tag);
// Update required size of subexpression-tracking data structure:
s->dfa_maxmap = max(s->dfa_maxmap, dfa->num_map_items());
s->dfa_maxtag = max(s->dfa_maxtag, dfa->num_tags());
s->dfas[input] = dfa;
return dfa;
}
// ------------------------------------------------------------------------
stapdfa::stapdfa (const string& func_name, const string& re,
const token *tok, bool do_unescape, bool do_tag)
: func_name(func_name), orig_input(re), tok(tok), do_tag(do_tag)
{
try
{
regex_parser p(re, do_unescape);
ast = p.parse (do_tag);
content = stapregex_compile (ast, "goto match_success;", "goto match_fail;");
}
catch (const regex_error &e)
{
if (e.pos >= 0)
throw SEMANTIC_ERROR(_F("regex compilation error (at position %d): %s",
e.pos, e.what()), tok);
else
throw SEMANTIC_ERROR(_F("regex compilation error: %s", e.what()), tok);
}
}
stapdfa::~stapdfa ()
{
delete content;
delete ast;
}
unsigned
stapdfa::num_states () const
{
return content->nstates;
}
unsigned
stapdfa::num_map_items () const
{
return content->nmapitems;
}
unsigned
stapdfa::num_tags () const
{
return content->ntags;
}
void
stapdfa::emit_declaration (translator_output *o) const
{
o->newline() << "// DFA for \"" << orig_input << "\"";
o->newline() << "int " << func_name << " (struct context * __restrict__ c, const char *str);";
o->newline() << "int " << func_name << " (struct context * __restrict__ c, const char *str) {";
o->indent(1);
// Emit a SystemTap function body (as if an embedded-C snippet) that
// invokes the DFA on the argument named 'str', saves a boolean
// value (0 or 1) in the return value, and updates the probe
// context's match object with subexpression contents as
// appropriate.
o->newline() << "const char *cur = str;";
o->newline() << "const char *start = cur;";
o->newline() << "const char *mar;";
if (do_tag)
{
o->newline() << "#define YYTAG(t,s) (c->last_match.tag_states[(t)][(s)])";
o->newline() << "#define YYFINAL(t) (c->last_match.tag_vals[(t)])";
}
o->newline() << "#define YYCTYPE char";
o->newline() << "#define YYSTART start";
o->newline() << "#define YYCURSOR cur";
o->newline() << "#define YYLENGTH (YYCURSOR-YYSTART)";
o->newline() << "#define YYLIMIT cur";
o->newline() << "#define YYMARKER mar";
// XXX: YYFILL is disabled as it doesn't play well with ^
o->newline();
try
{
content->emit(o);
}
catch (const regex_error &e)
{
if (e.pos >= 0)
throw SEMANTIC_ERROR(_F("regex compilation error (at position %d): %s",
e.pos, e.what()), tok);
else
throw SEMANTIC_ERROR(_F("regex compilation error: %s", e.what()), tok);
}
if (do_tag)
{
o->newline() << "#undef YYTAG";
o->newline() << "#undef YYFINAL";
}
o->newline() << "#undef YYCTYPE";
o->newline() << "#undef YYSTART";
o->newline() << "#undef YYCURSOR";
o->newline() << "#undef YYLENGTH";
o->newline() << "#undef YYLIMIT";
o->newline() << "#undef YYMARKER";
o->newline() << "match_success:";
if (do_tag)
{
o->newline() << "strlcpy (c->last_match.matched_str, str, MAXSTRINGLEN);";
o->newline() << "c->last_match.result = 1;";
content->emit_tagsave(o, "c->last_match.tag_states", "c->last_match.tag_vals", "c->last_match.num_final_tags");
}
o->newline() << "return 1;";
o->newline() << "match_fail:";
if (do_tag)
{
o->newline() << "strlcpy (c->last_match.matched_str, str, MAXSTRINGLEN);";
o->newline() << "c->last_match.result = 0;";
}
o->newline() << "return 0;";
o->newline(-1) << "}";
}
void
stapdfa::emit_matchop_start (translator_output *o) const
{
o->line() << "(" << func_name << "(c, ("; // XXX: assumes context is available
}
void
stapdfa::emit_matchop_end (translator_output *o) const
{
o->line() << ")))";
}
void
stapdfa::print (std::ostream& o) const
{
translator_output to(o); print(&to);
}
void
stapdfa::print (translator_output *o) const
{
o->line() << "STAPDFA (" << func_name << ", \"" << orig_input << "\") {";
content->print(o);
o->newline(-1) << "}";
}
std::ostream&
operator << (std::ostream &o, const stapdfa& d)
{
d.print (o);
return o;
}
/* vim: set sw=2 ts=8 cino=>4,n-2,{2,^-2,t0,(0,u0,w1,M1 : */
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