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# Copyright (C) 2003-2018 Free Software Foundation, Inc.
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2, or (at your option)
# any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
package Automake::Rule;
use 5.006;
use strict;
use Carp;
use Automake::Item;
use Automake::RuleDef;
use Automake::ChannelDefs;
use Automake::Channels;
use Automake::Options;
use Automake::Condition qw (TRUE FALSE);
use Automake::DisjConditions;
require Exporter;
use vars '@ISA', '@EXPORT', '@EXPORT_OK';
@ISA = qw/Automake::Item Exporter/;
@EXPORT = qw (reset register_suffix_rule next_in_suffix_chain
suffixes rules $KNOWN_EXTENSIONS_PATTERN
depend %dependencies %actions register_action
accept_extensions
reject_rule msg_rule msg_cond_rule err_rule err_cond_rule
rule rrule ruledef rruledef);
=head1 NAME
Automake::Rule - support for rules definitions
=head1 SYNOPSIS
use Automake::Rule;
use Automake::RuleDef;
=head1 DESCRIPTION
This package provides support for Makefile rule definitions.
An C<Automake::Rule> is a rule name associated to possibly
many conditional definitions. These definitions are instances
of C<Automake::RuleDef>.
Therefore obtaining the value of a rule under a given
condition involves two lookups. One to look up the rule,
and one to look up the conditional definition:
my $rule = rule $name;
if ($rule)
{
my $def = $rule->def ($cond);
if ($def)
{
return $def->location;
}
...
}
...
when it is known that the rule and the definition
being looked up exist, the above can be simplified to
return rule ($name)->def ($cond)->location; # do not write this.
but is better written
return rrule ($name)->rdef ($cond)->location;
or even
return rruledef ($name, $cond)->location;
The I<r> variants of the C<rule>, C<def>, and C<ruledef> methods add
an extra test to ensure that the lookup succeeded, and will diagnose
failures as internal errors (with a message which is much more
informative than Perl's warning about calling a method on a
non-object).
=head2 Global variables
=over 4
=cut
my $_SUFFIX_RULE_PATTERN =
'^(\.[a-zA-Z0-9_(){}$+@\-]+)(\.[a-zA-Z0-9_(){}$+@\-]+)' . "\$";
my @_suffixes = ();
my @_known_extensions_list = ();
my %_rule_dict = ();
# See comments in the implementation of the 'next_in_suffix_chain()'
# variable for details.
my %_suffix_rules;
# Same as $suffix_rules, but records only the default rules
# supplied by the languages Automake supports.
my %_suffix_rules_builtin;
=item C<%dependencies>
Holds the dependencies of targets which dependencies are factored.
Typically, C<.PHONY> will appear in plenty of F<*.am> files, but must
be output once. Arguably all pure dependencies could be subject to
this factoring, but it is not unpleasant to have paragraphs in
Makefile: keeping related stuff altogether.
=cut
use vars '%dependencies';
=item <%actions>
Holds the factored actions. Tied to C<%dependencies>, i.e., filled
only when keys exists in C<%dependencies>.
=cut
use vars '%actions';
=item C<$KNOWN_EXTENSIONS_PATTERN>
Pattern that matches all know input extensions (i.e. extensions used
by the languages supported by Automake). Using this pattern (instead
of '\..*$') to match extensions allows Automake to support dot-less
extensions.
New extensions should be registered with C<accept_extensions>.
=cut
use vars qw ($KNOWN_EXTENSIONS_PATTERN);
$KNOWN_EXTENSIONS_PATTERN = "";
=back
=head2 Error reporting functions
In these functions, C<$rule> can be either a rule name, or
an instance of C<Automake::Rule>.
=over 4
=item C<err_rule ($rule, $message, [%options])>
Uncategorized errors about rules.
=cut
sub err_rule ($$;%)
{
msg_rule ('error', @_);
}
=item C<err_cond_rule ($cond, $rule, $message, [%options])>
Uncategorized errors about conditional rules.
=cut
sub err_cond_rule ($$$;%)
{
msg_cond_rule ('error', @_);
}
=item C<msg_cond_rule ($channel, $cond, $rule, $message, [%options])>
Messages about conditional rules.
=cut
sub msg_cond_rule ($$$$;%)
{
my ($channel, $cond, $rule, $msg, %opts) = @_;
my $r = ref ($rule) ? $rule : rrule ($rule);
msg $channel, $r->rdef ($cond)->location, $msg, %opts;
}
=item C<msg_rule ($channel, $targetname, $message, [%options])>
Messages about rules.
=cut
sub msg_rule ($$$;%)
{
my ($channel, $rule, $msg, %opts) = @_;
my $r = ref ($rule) ? $rule : rrule ($rule);
# Don't know which condition is concerned. Pick any.
my $cond = $r->conditions->one_cond;
msg_cond_rule ($channel, $cond, $r, $msg, %opts);
}
=item C<$bool = reject_rule ($rule, $error_msg)>
Bail out with C<$error_msg> if a rule with name C<$rule> has been
defined.
Return true iff C<$rule> is defined.
=cut
sub reject_rule ($$)
{
my ($rule, $msg) = @_;
if (rule ($rule))
{
err_rule $rule, $msg;
return 1;
}
return 0;
}
=back
=head2 Administrative functions
=over 4
=item C<accept_extensions (@exts)>
Update C<$KNOWN_EXTENSIONS_PATTERN> to recognize the extensions
listed in C<@exts>. Extensions should contain a dot if needed.
=cut
sub accept_extensions (@)
{
push @_known_extensions_list, @_;
$KNOWN_EXTENSIONS_PATTERN =
'(?:' . join ('|', map (quotemeta, @_known_extensions_list)) . ')';
}
=item C<rules>
Return the list of all L<Automake::Rule> instances. (I.e., all
rules defined so far.)
=cut
sub rules ()
{
return values %_rule_dict;
}
=item C<register_action($target, $action)>
Append the C<$action> to C<$actions{$target}> taking care of special
cases.
=cut
sub register_action ($$)
{
my ($target, $action) = @_;
if ($actions{$target})
{
$actions{$target} .= "\n$action" if $action;
}
else
{
$actions{$target} = $action;
}
}
=item C<Automake::Rule::reset>
The I<forget all> function. Clears all known rules and resets some
other internal data.
=cut
sub reset()
{
%_rule_dict = ();
@_suffixes = ();
%_suffix_rules = %_suffix_rules_builtin;
%dependencies =
(
# Texinfoing.
'dvi' => [],
'dvi-am' => [],
'pdf' => [],
'pdf-am' => [],
'ps' => [],
'ps-am' => [],
'info' => [],
'info-am' => [],
'html' => [],
'html-am' => [],
# Installing/uninstalling.
'install-data-am' => [],
'install-exec-am' => [],
'uninstall-am' => [],
'install-man' => [],
'uninstall-man' => [],
'install-dvi' => [],
'install-dvi-am' => [],
'install-html' => [],
'install-html-am' => [],
'install-info' => [],
'install-info-am' => [],
'install-pdf' => [],
'install-pdf-am' => [],
'install-ps' => [],
'install-ps-am' => [],
'installcheck-am' => [],
# Cleaning.
'clean-am' => [],
'mostlyclean-am' => [],
'maintainer-clean-am' => [],
'distclean-am' => [],
'clean' => [],
'mostlyclean' => [],
'maintainer-clean' => [],
'distclean' => [],
# Tarballing.
'dist-all' => [],
'.PHONY' => [],
'.PRECIOUS' => [],
# Recursive install targets (so "make -n install" works for BSD Make).
'.MAKE' => [],
);
%actions = ();
}
=item C<next_in_suffix_chain ($ext1, $ext2)>
Return the target suffix for the next rule to use to reach C<$ext2>
from C<$ext1>, or C<undef> if no such rule exists.
=cut
sub next_in_suffix_chain ($$)
{
my ($ext1, $ext2) = @_;
return undef unless (exists $_suffix_rules{$ext1} and
exists $_suffix_rules{$ext1}{$ext2});
return $_suffix_rules{$ext1}{$ext2}[0];
}
=item C<register_suffix_rule ($where, $src, $dest)>
Register a suffix rule defined on C<$where> that transforms
files ending in C<$src> into files ending in C<$dest>.
=cut
sub register_suffix_rule ($$$)
{
my ($where, $src, $dest) = @_;
my $suffix_rules = $where->{'position'} ? \%_suffix_rules
: \%_suffix_rules_builtin;
verb "Sources ending in $src become $dest";
push @_suffixes, $src, $dest;
# When transforming sources to objects, Automake uses the
# %suffix_rules to move from each source extension to
# '.$(OBJEXT)', not to '.o' or '.obj'. However some people
# define suffix rules for '.o' or '.obj', so internally we will
# consider these extensions equivalent to '.$(OBJEXT)'. We
# CANNOT rewrite the target (i.e., automagically replace '.o'
# and '.obj' by '.$(OBJEXT)' in the output), or warn the user
# that (s)he'd better use '.$(OBJEXT)', because Automake itself
# output suffix rules for '.o' or '.obj' ...
$dest = '.$(OBJEXT)' if ($dest eq '.o' || $dest eq '.obj');
# ----------------------------------------------------------------------
# The $suffix_rules variable maps the source extension for all suffix
# rules seen to a hash whose keys are the possible output extensions.
#
# Note that this is transitively closed by construction:
# if we have
#
# exists $suffix_rules{$ext1}{$ext2}
# && exists $suffix_rules{$ext2}{$ext3}
#
# then we also have
#
# exists $suffix_rules{$ext1}{$ext3}
#
# So it's easy to check whether '.foo' can be transformed to
# '.$(OBJEXT)' by checking whether $suffix_rules{'.foo'}{'.$(OBJEXT)'}
# exists. This will work even if transforming '.foo' to '.$(OBJEXT)'
# involves a chain of several suffix rules.
#
# The value of $suffix_rules{$ext1}{$ext2} is a pair [$next_sfx, $dist]
# where $next_sfx is target suffix for the next rule to use to reach
# $ext2, and $dist the distance to $ext2.
# ----------------------------------------------------------------------
# Register $dest as a possible destination from $src.
# We might have the create the \hash.
if (exists $suffix_rules->{$src})
{
$suffix_rules->{$src}{$dest} = [ $dest, 1 ];
}
else
{
$suffix_rules->{$src} = { $dest => [ $dest, 1 ] };
}
# If we know how to transform $dest in something else, then
# we know how to transform $src in that "something else".
if (exists $suffix_rules->{$dest})
{
for my $dest2 (keys %{$suffix_rules->{$dest}})
{
my $dist = $suffix_rules->{$dest}{$dest2}[1] + 1;
# Overwrite an existing $src->$dest2 path only if
# the path via $dest which is shorter.
if (! exists $suffix_rules->{$src}{$dest2}
|| $suffix_rules->{$src}{$dest2}[1] > $dist)
{
$suffix_rules->{$src}{$dest2} = [ $dest, $dist ];
}
}
}
# Similarly, any extension that can be derived into $src
# can be derived into the same extensions as $src can.
my @dest2 = keys %{$suffix_rules->{$src}};
for my $src2 (keys %$suffix_rules)
{
if (exists $suffix_rules->{$src2}{$src})
{
for my $dest2 (@dest2)
{
my $dist = $suffix_rules->{$src}{$dest2} + 1;
# Overwrite an existing $src2->$dest2 path only if
# the path via $src is shorter.
if (! exists $suffix_rules->{$src2}{$dest2}
|| $suffix_rules->{$src2}{$dest2}[1] > $dist)
{
$suffix_rules->{$src2}{$dest2} = [ $src, $dist ];
}
}
}
}
}
=item C<@list = suffixes>
Return the list of known suffixes.
=cut
sub suffixes ()
{
return @_suffixes;
}
=item C<rule ($rulename)>
Return the C<Automake::Rule> object for the rule
named C<$rulename> if defined. Return 0 otherwise.
=cut
sub rule ($)
{
my ($name) = @_;
# Strip $(EXEEXT) from $name, so we can diagnose
# a clash if 'ctags$(EXEEXT):' is redefined after 'ctags:'.
$name =~ s,\$\(EXEEXT\)$,,;
return $_rule_dict{$name} || 0;
}
=item C<ruledef ($rulename, $cond)>
Return the C<Automake::RuleDef> object for the rule named
C<$rulename> if defined in condition C<$cond>. Return false
if the condition or the rule does not exist.
=cut
sub ruledef ($$)
{
my ($name, $cond) = @_;
my $rule = rule $name;
return $rule && $rule->def ($cond);
}
=item C<rrule ($rulename)
Return the C<Automake::Rule> object for the variable named
C<$rulename>. Abort with an internal error if the variable was not
defined.
The I<r> in front of C<var> stands for I<required>. One
should call C<rvar> to assert the rule's existence.
=cut
sub rrule ($)
{
my ($name) = @_;
my $r = rule $name;
prog_error ("undefined rule $name\n" . &rules_dump)
unless $r;
return $r;
}
=item C<rruledef ($varname, $cond)>
Return the C<Automake::RuleDef> object for the rule named
C<$rulename> if defined in condition C<$cond>. Abort with an internal
error if the condition or the rule does not exist.
=cut
sub rruledef ($$)
{
my ($name, $cond) = @_;
return rrule ($name)->rdef ($cond);
}
# Create the variable if it does not exist.
# This is used only by other functions in this package.
sub _crule ($)
{
my ($name) = @_;
my $r = rule $name;
return $r if $r;
return _new Automake::Rule $name;
}
sub _new ($$)
{
my ($class, $name) = @_;
# Strip $(EXEEXT) from $name, so we can diagnose
# a clash if 'ctags$(EXEEXT):' is redefined after 'ctags:'.
(my $keyname = $name) =~ s,\$\(EXEEXT\)$,,;
my $self = Automake::Item::new ($class, $name);
$_rule_dict{$keyname} = $self;
return $self;
}
sub _rule_defn_with_exeext_awareness ($$$)
{
my ($target, $cond, $where) = @_;
# For now 'foo:' will override 'foo$(EXEEXT):'. This is temporary,
# though, so we emit a warning.
(my $noexe = $target) =~ s/\$\(EXEEXT\)$//;
my $noexerule = rule $noexe;
my $tdef = $noexerule ? $noexerule->def ($cond) : undef;
if ($noexe ne $target
&& $tdef
&& $noexerule->name ne $target)
{
# The no-exeext option enables this feature.
if (! option 'no-exeext')
{
msg ('obsolete', $tdef->location,
"deprecated feature: target '$noexe' overrides "
. "'$noexe\$(EXEEXT)'\n"
. "change your target to read '$noexe\$(EXEEXT)'",
partial => 1);
msg ('obsolete', $where, "target '$target' was defined here");
}
}
return $tdef;
}
sub _maybe_warn_about_duplicated_target ($$$$$$)
{
my ($target, $tdef, $source, $owner, $cond, $where) = @_;
my $oldowner = $tdef->owner;
# Ok, it's the name target, but the name maybe different because
# 'foo$(EXEEXT)' and 'foo' have the same key in our table.
my $oldname = $tdef->name;
# Don't mention true conditions in diagnostics.
my $condmsg =
$cond == TRUE ? '' : (" in condition '" . $cond->human . "'");
if ($owner == RULE_USER)
{
if ($oldowner == RULE_USER)
{
# Ignore '%'-style pattern rules. We'd need the
# dependencies to detect duplicates, and they are
# already diagnosed as unportable by -Wportability.
if ($target !~ /^[^%]*%[^%]*$/)
{
## FIXME: Presently we can't diagnose duplicate user rules
## because we don't distinguish rules with commands
## from rules that only add dependencies. E.g.,
## .PHONY: foo
## .PHONY: bar
## is legitimate. This is checked in the 'phony.sh' test.
# msg ('syntax', $where,
# "redefinition of '$target'$condmsg ...", partial => 1);
# msg_cond_rule ('syntax', $cond, $target,
# "... '$target' previously defined here");
}
}
else
{
# Since we parse the user Makefile.am before reading
# the Automake fragments, this condition should never happen.
prog_error ("user target '$target'$condmsg seen after Automake's"
. " definition\nfrom " . $tdef->source);
}
}
else # $owner == RULE_AUTOMAKE
{
if ($oldowner == RULE_USER)
{
# -am targets listed in %dependencies support a -local
# variant. If the user tries to override TARGET or
# TARGET-am for which there exists a -local variant,
# just tell the user to use it.
my $hint = 0;
my $noam = $target;
$noam =~ s/-am$//;
if (exists $dependencies{"$noam-am"})
{
$hint = "consider using $noam-local instead of $target";
}
msg_cond_rule ('override', $cond, $target,
"user target '$target' defined here"
. "$condmsg ...", partial => 1);
msg ('override', $where,
"... overrides Automake target '$oldname' defined here",
partial => $hint);
msg_cond_rule ('override', $cond, $target, $hint)
if $hint;
}
else # $oldowner == RULE_AUTOMAKE
{
# Automake should ignore redefinitions of its own
# rules if they came from the same file. This makes
# it easier to process a Makefile fragment several times.
# However it's an error if the target is defined in many
# files. E.g., the user might be using bin_PROGRAMS = ctags
# which clashes with our 'ctags' rule.
# (It would be more accurate if we had a way to compare
# the *content* of both rules. Then $targets_source would
# be useless.)
my $oldsource = $tdef->source;
if (not ($source eq $oldsource && $target eq $oldname))
{
msg ('syntax',
$where, "redefinition of '$target'$condmsg ...",
partial => 1);
msg_cond_rule ('syntax', $cond, $target,
"... '$oldname' previously defined here");
}
}
}
}
# Return the list of conditionals in which the rule was defined. In case
# an ambiguous conditional definition is detected, return the empty list.
sub _conditionals_for_rule ($$$$)
{
my ($rule, $owner, $cond, $where) = @_;
my $target = $rule->name;
my @conds;
my ($message, $ambig_cond) = $rule->conditions->ambiguous_p ($target, $cond);
return $cond if !$message; # No ambiguity.
if ($owner == RULE_USER)
{
# For user rules, just diagnose the ambiguity.
msg 'syntax', $where, "$message ...", partial => 1;
msg_cond_rule ('syntax', $ambig_cond, $target,
"... '$target' previously defined here");
return ();
}
# FIXME: for Automake rules, we can't diagnose ambiguities yet.
# The point is that Automake doesn't propagate conditions
# everywhere. For instance &handle_PROGRAMS doesn't care if
# bin_PROGRAMS was defined conditionally or not.
# On the following input
# if COND1
# foo:
# ...
# else
# bin_PROGRAMS = foo
# endif
# &handle_PROGRAMS will attempt to define a 'foo:' rule
# in condition TRUE (which conflicts with COND1). Fixing
# this in &handle_PROGRAMS and siblings seems hard: you'd
# have to explain &file_contents what to do with a
# condition. So for now we do our best *here*. If 'foo:'
# was already defined in condition COND1 and we want to define
# it in condition TRUE, then define it only in condition !COND1.
# (See cond14.sh and cond15.sh for some test cases.)
@conds = $rule->not_always_defined_in_cond ($cond)->conds;
# No conditions left to define the rule.
# Warn, because our workaround is meaningless in this case.
if (scalar @conds == 0)
{
msg 'syntax', $where, "$message ...", partial => 1;
msg_cond_rule ('syntax', $ambig_cond, $target,
"... '$target' previously defined here");
return ();
}
return @conds;
}
=item C<@conds = define ($rulename, $source, $owner, $cond, $where)>
Define a new rule. C<$rulename> is the list of targets. C<$source>
is the filename the rule comes from. C<$owner> is the owner of the
rule (C<RULE_AUTOMAKE> or C<RULE_USER>). C<$cond> is the
C<Automake::Condition> under which the rule is defined. C<$where> is
the C<Automake::Location> where the rule is defined.
Returns a (possibly empty) list of C<Automake::Condition>s where the
rule's definition should be output.
=cut
sub define ($$$$$)
{
my ($target, $source, $owner, $cond, $where) = @_;
prog_error "$where is not a reference"
unless ref $where;
prog_error "$cond is not a reference"
unless ref $cond;
# Don't even think about defining a rule in condition FALSE.
return () if $cond == FALSE;
my $tdef = _rule_defn_with_exeext_awareness ($target, $cond, $where);
# A GNU make-style pattern rule has a single "%" in the target name.
msg ('portability', $where,
"'%'-style pattern rules are a GNU make extension")
if $target =~ /^[^%]*%[^%]*$/;
# See whether this is a duplicated target declaration.
if ($tdef)
{
# Diagnose invalid target redefinitions, if any. Note that some
# target redefinitions are valid (e.g., for multiple-targets
# pattern rules).
_maybe_warn_about_duplicated_target ($target, $tdef, $source,
$owner, $cond, $where);
# Return so we don't redefine the rule in our tables, don't check
# for ambiguous condition, etc. The rule will be output anyway
# because '&read_am_file' ignores the return code.
return ();
}
my $rule = _crule $target;
# Conditions for which the rule should be defined. Due to some
# complications in the automake internals, this aspect is not as
# obvious as it might be, and in come cases this list must contain
# other entries in addition to '$cond'. See the comments in
# '_conditionals_for_rule' for a rationale.
my @conds = _conditionals_for_rule ($rule, $owner, $cond, $where);
# Stop if we had ambiguous conditional definitions.
return unless @conds;
# Finally define this rule.
for my $c (@conds)
{
my $def = new Automake::RuleDef ($target, '', $where->clone,
$owner, $source);
$rule->set ($c, $def);
}
# We honor inference rules with multiple targets because many
# makes support this and people use it. However this is disallowed
# by POSIX. We'll print a warning later.
my $target_count = 0;
my $inference_rule_count = 0;
for my $t (split (' ', $target))
{
++$target_count;
# Check if the rule is a suffix rule: either it's a rule for
# two known extensions...
if ($t =~ /^($KNOWN_EXTENSIONS_PATTERN)($KNOWN_EXTENSIONS_PATTERN)$/
# ...or it's a rule with unknown extensions (i.e., the rule
# looks like '.foo.bar:' but '.foo' or '.bar' are not
# declared in SUFFIXES and are not known language
# extensions). Automake will complete SUFFIXES from
# @suffixes automatically (see handle_footer).
|| ($t =~ /$_SUFFIX_RULE_PATTERN/o && accept_extensions($1)))
{
++$inference_rule_count;
register_suffix_rule ($where, $1, $2);
}
}
# POSIX allows multiple targets before the colon, but disallows
# definitions of multiple inference rules. It's also
# disallowed to mix plain targets with inference rules.
msg ('portability', $where,
"inference rules can have only one target before the colon (POSIX)")
if $inference_rule_count > 0 && $target_count > 1;
return @conds;
}
=item C<depend ($target, @deps)>
Adds C<@deps> to the dependencies of target C<$target>. This should
be used only with factored targets (those appearing in
C<%dependees>).
=cut
sub depend ($@)
{
my ($category, @dependees) = @_;
push (@{$dependencies{$category}}, @dependees);
}
=back
=head1 SEE ALSO
L<Automake::RuleDef>, L<Automake::Condition>,
L<Automake::DisjConditions>, L<Automake::Location>.
=cut
1;