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Random improvements. Starting to refactor the prototype and function
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detection logic so it can be used as the basis for lots of fun
transformations.
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@regehr
regehr committed Jun 29, 2011
1 parent 484aca2 commit 6b1712b
Showing 1 changed file with 72 additions and 34 deletions.
106 changes: 72 additions & 34 deletions utah/scripts/reduce/c_delta.pl
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Expand Up @@ -18,7 +18,10 @@
# invalid code and also most of its changes do not reduce program size
# by a large amount. Thus, it is best used as a second pass with a
# faster Delta like the Berkeley one trimming the obviously irrelevant
# code.
# code. Actually, generating syntactically invalid code is not a
# performance problem at all: these are discarded very quickly be a
# typical "interestingness" script. The vast majority of a Delta's
# time is spent checking interestingness of syntactically valid code.
#
####################################################################

Expand All @@ -29,21 +32,24 @@
# add passes to
# turn checksum calls into regular printfs

# harder
# not so easy
# transform a function to return void
# inline a function call
# un-nest nested calls in expressions
# move arguments and locals to global scope
# remove level of pointer indirection
# remove array dimension
# remove argument from function, including all calls
# turn a union type into a struct

# write code to adapatively run multiple instances of a
# transformation when this has good expected value
# measure cost of success vs. failure, take into account
# proabability of success
# eventually back off to linear scan
# could run on multiple cores once randomization is added
# also, run the more expensive test (with chucky's tool) even
# less often

# watch for unexpected abnormal compiler outputs

Expand All @@ -58,6 +64,7 @@
######################################################################

my $DEBUG = 0;
my $INDENT_OPTS = "-bad -bap -bc -cs -pcs -prs -saf -sai -saw -sob -ss -bl ";

######################################################################

Expand Down Expand Up @@ -165,7 +172,7 @@
my $orig_prog_len;

sub print_pct () {
my $pct = length($prog)*100.0/$orig_prog_len;
my $pct = 100 - (length($prog)*100.0/$orig_prog_len);
printf "(%.1f %%)\n", $pct;
}

Expand Down Expand Up @@ -363,14 +370,15 @@ ($)
}
}
}
} elsif ($method eq "blanks_all") {
if ($prog =~ s/\s{2,}/ /g) {
} elsif ($method eq "all_blanks") {
if ($prog =~ s/\s{2,}/ /g ||
$prog =~ s/:(\S)/:\n$1/g) {
$worked |= delta_test ($method, 0);
}
return 0;
} elsif ($method eq "indent") {
write_file();
system "indent $cfile";
system "indent $INDENT_OPTS $cfile";
read_file();
$worked |= delta_test ($method, 1);
return 0;
Expand All @@ -381,38 +389,40 @@ ($)
substr ($prog, $pos, $len) = " ";
$worked |= delta_test ($method, 0);
}
} elsif ($method eq "parens_exclusive") {
if (substr($prog, $pos, 1) eq "(") {
my $p2 = find_match ($pos+1,"(",")");
if ($p2 != -1) {
die if (substr($prog, $pos, 1) ne "(");
die if (substr($prog, $p2, 1) ne ")");
substr ($prog, $p2, 1) = "";
substr ($prog, $pos, 1) = "";
print "deleting at $pos--$p2 : ";
$worked |= delta_test ($method, 0);
}
}
} elsif ($method eq "move_func") {
my $first = substr($prog, 0, $pos);
my $rest = substr($prog, $pos);
my $proto2 = $proto;
die if (!($proto2 =~ s/XXX/$fname/));
if ($rest =~ /^($proto2)/) {
my $proto_start;
my $proto_end;
my $func_start;
my $func_end;
if ($rest =~ /^($borderorspc$proto2)/) {
my $realproto = $1;
$proto_start = length($first) + $-[0];
$proto_end = length($first) + $+[0];
my $fname = $+{fname};
print "found prototype for '$fname'\n";
my $func2 = $func;
die if (!($func2 =~ s/XXX/$fname/));
if ($rest =~ s/($func2)//) {
if ($rest =~ /($func2)/) {
my $body = $1;
print "got body!\n";
print "replacing < $realproto > with < $body >\n";
substr ($rest, 0, length($realproto)) = $body;
$prog = $first.$rest;
$worked |= delta_test ($method, 0);
$func_start = length ($first) + $-[0];
$func_end = length ($first) + $+[0];
print "got body as well\n";
}
}
}

if (defined($proto_start) && defined($func_start)) {
my $proto = substr ($prog, $proto_start, $proto_end - $proto_start);
my $bod = substr ($prog, $func_start, $func_end - $func_start, "");
substr ($prog, $proto_start, $proto_end - $proto_start) = $bod;
print "replacing < $proto > with < $bod >\n";
$worked |= delta_test ($method, 0);
$pos += $proto_end - $proto_start;
}

} elsif ($method eq "ternary") {
my $first = substr($prog, 0, $pos);
my $rest = substr($prog, $pos);
Expand Down Expand Up @@ -462,16 +472,44 @@ ($)
print "replacing $n1 with $n2\n";
$worked |= delta_test ($method, 0);
}
} elsif ($method eq "brackets_exclusive") {
} elsif ($method eq "parens") {
if (substr($prog, $pos, 1) eq "(") {
my $p2 = find_match ($pos+1,"(",")");
if ($p2 != -1) {
die if (substr($prog, $pos, 1) ne "(");
die if (substr($prog, $p2, 1) ne ")");

my $del = substr ($prog, $pos, $p2-$pos+1, "");
print "deleting '$del' at $pos--$p2 : ";
my $res = delta_test ($method, 0);
$worked |= $res;

if (!$res) {
substr ($prog, $p2, 1) = "";
substr ($prog, $pos, 1) = "";
print "deleting at $pos--$p2 : ";
$worked |= delta_test ($method, 0);
}
}
}
} elsif ($method eq "brackets") {
if (substr($prog, $pos, 1) eq "{") {
my $p2 = find_match ($pos+1,"{","}");
if ($p2 != -1) {
die if (substr($prog, $pos, 1) ne "{");
die if (substr($prog, $p2, 1) ne "}");
substr ($prog, $p2, 1) = "";
substr ($prog, $pos, 1) = "";
print "deleting at $pos--$p2 : ";
$worked |= delta_test ($method, 0);

my $del = substr ($prog, $pos, $p2-$pos+1, "");
print "deleting '$del' at $pos--$p2 : ";
my $res = delta_test ($method, 0);
$worked |= $res;

if (!$res) {
substr ($prog, $p2, 1) = "";
substr ($prog, $pos, 1) = "";
print "deleting at $pos--$p2 : ";
$worked |= delta_test ($method, 0);
}
}
}
} else {
Expand All @@ -488,12 +526,12 @@ ($)

my %all_methods = (

"blanks_all" => 0,
"all_blanks" => 0,
"blanks" => 1,
"move_func" => 2,
"brackets_exclusive" => 2,
"brackets" => 2,
"ternary" => 2,
"parens_exclusive" => 3,
"parens" => 3,
"replace_regex" => 4,
"shorten_ints" => 5,
"indent" => 15,
Expand Down

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