llvm-6502/tools/llvm-config/find-cycles.pl

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#!/usr/bin/perl
#
# Program: find-cycles.pl
#
# Synopsis: Given a list of possibly cyclic dependencies, merge all the
# cycles. This makes it possible to topologically sort the
# dependencies between different parts of LLVM.
#
# Syntax: find-cycles.pl < LibDeps.txt > FinalLibDeps.txt
#
# Input: cycmem1: cycmem2 dep1 dep2
# cycmem2: cycmem1 dep3 dep4
# boring: dep4
#
# Output: cycmem1 cycmem2: dep1 dep2 dep3 dep4
# boring: dep4
#
# This file was written by Eric Kidd, and is placed into the public domain.
#
use 5.006;
use strict;
use warnings;
my %DEPS;
my @CYCLES;
sub find_all_cycles;
# Read our dependency information.
while (<>) {
chomp;
my ($module, $dependency_str) = /^\s*([^:]+):\s*(.*)\s*$/;
die "Malformed data: $_" unless defined $dependency_str;
my @dependencies = split(/ /, $dependency_str);
$DEPS{$module} = \@dependencies;
}
# Partition our raw dependencies into sets of cyclically-connected nodes.
find_all_cycles();
# Print out the finished cycles, with their dependencies.
my @output;
my $cycles_found = 0;
foreach my $cycle (@CYCLES) {
my @modules = sort keys %{$cycle};
# Merge the dependencies of all modules in this cycle.
my %dependencies;
foreach my $module (@modules) {
@dependencies{@{$DEPS{$module}}} = 1;
}
# Prune the known cyclic dependencies.
foreach my $module (@modules) {
delete $dependencies{$module};
}
# Warn about possible linker problems.
my @archives = grep(/\.a$/, @modules);
if (@archives > 1) {
$cycles_found = $cycles_found + 1;
print STDERR "find-cycles.pl: Circular dependency between *.a files:\n";
print STDERR "find-cycles.pl: ", join(' ', @archives), "\n";
push @modules, @archives; # WORKAROUND: Duplicate *.a files. Ick.
} elsif (@modules > 1) {
$cycles_found = $cycles_found + 1;
print STDERR "find-cycles.pl: Circular dependency between *.o files:\n";
print STDERR "find-cycles.pl: ", join(' ', @modules), "\n";
push @modules, @modules; # WORKAROUND: Duplicate *.o files. Ick.
}
# Add to our output. (@modules is already as sorted as we need it to be.)
push @output, (join(' ', @modules) . ': ' .
join(' ', sort keys %dependencies) . "\n");
}
print sort @output;
exit $cycles_found;
#==========================================================================
# Depedency Cycle Support
#==========================================================================
# For now, we have cycles in our dependency graph. Ideally, each cycle
# would be collapsed down to a single *.a file, saving us all this work.
#
# To understand this code, you'll need a working knowledge of Perl 5,
# and possibly some quality time with 'man perlref'.
my %SEEN;
my %CYCLES;
sub find_cycles ($@);
sub found_cycles ($@);
sub find_all_cycles {
# Find all multi-item cycles.
my @modules = sort keys %DEPS;
foreach my $module (@modules) { find_cycles($module); }
# Build fake one-item "cycles" for the remaining modules, so we can
# treat them uniformly.
foreach my $module (@modules) {
unless (defined $CYCLES{$module}) {
my %cycle = ($module, 1);
$CYCLES{$module} = \%cycle;
}
}
# Find all our unique cycles. We have to do this the hard way because
# we apparently can't store hash references as hash keys without making
# 'strict refs' sad.
my %seen;
foreach my $cycle (values %CYCLES) {
unless ($seen{$cycle}) {
$seen{$cycle} = 1;
push @CYCLES, $cycle;
}
}
}
# Walk through our graph depth-first (keeping a trail in @path), and report
# any cycles we find.
sub find_cycles ($@) {
my ($module, @path) = @_;
if (str_in_list($module, @path)) {
found_cycle($module, @path);
} else {
return if defined $SEEN{$module};
$SEEN{$module} = 1;
foreach my $dep (@{$DEPS{$module}}) {
find_cycles($dep, @path, $module);
}
}
}
# Give a cycle, attempt to merge it with pre-existing cycle data.
sub found_cycle ($@) {
my ($module, @path) = @_;
# Pop any modules which aren't part of our cycle.
while ($path[0] ne $module) { shift @path; }
#print join("->", @path, $module) . "\n";
# Collect the modules in our cycle into a hash.
my %cycle;
foreach my $item (@path) {
$cycle{$item} = 1;
if (defined $CYCLES{$item}) {
# Looks like we intersect with an existing cycle, so merge
# all those in, too.
foreach my $old_item (keys %{$CYCLES{$item}}) {
$cycle{$old_item} = 1;
}
}
}
# Update our global cycle table.
my $cycle_ref = \%cycle;
foreach my $item (keys %cycle) {
$CYCLES{$item} = $cycle_ref;
}
#print join(":", sort keys %cycle) . "\n";
}
sub str_in_list ($@) {
my ($str, @list) = @_;
foreach my $item (@list) {
return 1 if ($item eq $str);
}
return 0;
}