Profile of XSLoader.pm

Filename	/usr/local/perls/perl-5.26.1/lib/5.26.1/XSLoader.pm
Statements	Executed 0 statements in 0s

Subroutines
Calls	P	F	Exclusive Time	Inclusive Time	Subroutine
4	4	4	10.8ms	10.8ms	XSLoader::::loadXSLoader::load
0	0	0	0s	0s	XSLoader::::bootstrap_inheritXSLoader::bootstrap_inherit

Call graph for these subroutines as a Graphviz dot language file.

Line	State ments	Time on line	Calls	Time in subs	Code
1					# Generated from XSLoader_pm.PL (resolved %Config::Config value)
2					# This file is unique for every OS
3
4					package XSLoader;
5
6					$VERSION = "0.27";
7
8					#use strict;
9
10					package DynaLoader;
11
12					# No prizes for guessing why we don't say 'bootstrap DynaLoader;' here.
13					# NOTE: All dl_*.xs (including dl_none.xs) define a dl_error() XSUB
14					boot_DynaLoader('DynaLoader') if defined(&boot_DynaLoader) &&
15					!defined(&dl_error);
16					package XSLoader;
17
18					# spent 10.8ms within XSLoader::load which was called 4 times, avg 2.69ms/call: # once (5.32ms+0s) by IO::Uncompress::Adapter::Bunzip2::BEGIN@9 at line 62 of Compress/Raw/Bzip2.pm # once (2.10ms+0s) by Compress::Zlib::BEGIN@11 at line 126 of Compress/Raw/Zlib.pm # once (1.70ms+0s) by File::GlobMapper::BEGIN@10 at line 68 of File/Glob.pm # once (1.64ms+0s) by CPAN::has_inst at line 80 of Storable.pm sub load {
19					package DynaLoader;
20
21					my ($caller, $modlibname) = caller();
22					my $module = $caller;
23
24					if (@_) {
25					$module = $_[0];
26					} else {
27					$_[0] = $module;
28					}
29
30					# work with static linking too
31					my $boots = "$module\::bootstrap";
32					goto &$boots if defined &$boots;
33
34					goto \&XSLoader::bootstrap_inherit unless $module and defined &dl_load_file;
35
36					my @modparts = split(/::/,$module);
37					my $modfname = $modparts[-1];
38
39					my $modpname = join('/',@modparts);
40					my $c = () = split(/::/,$caller,-1);
41					$modlibname =~ s,[\\/][^\\/]+$,, while $c--; # Q&D basename
42					# Does this look like a relative path?
43					if ($modlibname !~ m{^/}) {
44					# Someone may have a #line directive that changes the file name, or
45					# may be calling XSLoader::load from inside a string eval. We cer-
46					# tainly do not want to go loading some code that is not in @INC,
47					# as it could be untrusted.
48					#
49					# We could just fall back to DynaLoader here, but then the rest of
50					# this function would go untested in the perl core, since all @INC
51					# paths are relative during testing. That would be a time bomb
52					# waiting to happen, since bugs could be introduced into the code.
53					#
54					# So look through @INC to see if $modlibname is in it. A rela-
55					# tive $modlibname is not a common occurrence, so this block is
56					# not hot code.
57					FOUND: {
58					for (@INC) {
59					if ($_ eq $modlibname) {
60					last FOUND;
61					}
62					}
63					# Not found. Fall back to DynaLoader.
64					goto \&XSLoader::bootstrap_inherit;
65					}
66					}
67					my $file = "$modlibname/auto/$modpname/$modfname.bundle";
68
69					# print STDERR "XSLoader::load for $module ($file)\n" if $dl_debug;
70
71					my $bs = $file;
72					$bs =~ s/(\.\w+)?(;\d*)?$/\.bs/; # look for .bs 'beside' the library
73
74					if (-s $bs) { # only read file if it's not empty
75					# print STDERR "BS: $bs ($^O, $dlsrc)\n" if $dl_debug;
76					eval { local @INC = ('.'); do $bs; };
77					warn "$bs: $@\n" if $@;
78					goto \&XSLoader::bootstrap_inherit;
79					}
80
81					goto \&XSLoader::bootstrap_inherit if not -f $file;
82
83					my $bootname = "boot_$module";
84					$bootname =~ s/\W/_/g;
85					@DynaLoader::dl_require_symbols = ($bootname);
86
87					my $boot_symbol_ref;
88
89					if ($boot_symbol_ref = dl_find_symbol( 0, $bootname )) {
90					goto boot; #extension library has already been loaded, e.g. darwin
91					}
92					# Many dynamic extension loading problems will appear to come from
93					# this section of code: XYZ failed at line 123 of DynaLoader.pm.
94					# Often these errors are actually occurring in the initialisation
95					# C code of the extension XS file. Perl reports the error as being
96					# in this perl code simply because this was the last perl code
97					# it executed.
98
99					my $libref = dl_load_file($file, 0) or do {
100					require Carp;
101					Carp::croak("Can't load '$file' for module $module: " . dl_error());
102					};
103					push(@DynaLoader::dl_librefs,$libref); # record loaded object
104
105					$boot_symbol_ref = dl_find_symbol($libref, $bootname) or do {
106					require Carp;
107					Carp::croak("Can't find '$bootname' symbol in $file\n");
108					};
109
110					push(@DynaLoader::dl_modules, $module); # record loaded module
111
112					boot:
113					my $xs = dl_install_xsub($boots, $boot_symbol_ref, $file);
114
115					# See comment block above
116					push(@DynaLoader::dl_shared_objects, $file); # record files loaded
117					return &$xs(@_);
118					}
119
120					sub bootstrap_inherit {
121					require DynaLoader;
122					goto \&DynaLoader::bootstrap_inherit;
123					}
124
125					1;
126
127
128					__END__
129
130					=head1 NAME
131
132					XSLoader - Dynamically load C libraries into Perl code
133
134					=head1 VERSION
135
136					Version 0.24
137
138					=head1 SYNOPSIS
139
140					package YourPackage;
141					require XSLoader;
142
143					XSLoader::load();
144
145					=head1 DESCRIPTION
146
147					This module defines a standard I<simplified> interface to the dynamic
148					linking mechanisms available on many platforms. Its primary purpose is
149					to implement cheap automatic dynamic loading of Perl modules.
150
151					For a more complicated interface, see L<DynaLoader>. Many (most)
152					features of C<DynaLoader> are not implemented in C<XSLoader>, like for
153					example the C<dl_load_flags>, not honored by C<XSLoader>.
154
155					=head2 Migration from C<DynaLoader>
156
157					A typical module using L<DynaLoader\|DynaLoader> starts like this:
158
159					package YourPackage;
160					require DynaLoader;
161
162					our @ISA = qw( OnePackage OtherPackage DynaLoader );
163					our $VERSION = '0.01';
164					bootstrap YourPackage $VERSION;
165
166					Change this to
167
168					package YourPackage;
169					use XSLoader;
170
171					our @ISA = qw( OnePackage OtherPackage );
172					our $VERSION = '0.01';
173					XSLoader::load 'YourPackage', $VERSION;
174
175					In other words: replace C<require DynaLoader> by C<use XSLoader>, remove
176					C<DynaLoader> from C<@ISA>, change C<bootstrap> by C<XSLoader::load>. Do not
177					forget to quote the name of your package on the C<XSLoader::load> line,
178					and add comma (C<,>) before the arguments (C<$VERSION> above).
179
180					Of course, if C<@ISA> contained only C<DynaLoader>, there is no need to have
181					the C<@ISA> assignment at all; moreover, if instead of C<our> one uses the
182					more backward-compatible
183
184					use vars qw($VERSION @ISA);
185
186					one can remove this reference to C<@ISA> together with the C<@ISA> assignment.
187
188					If no C<$VERSION> was specified on the C<bootstrap> line, the last line becomes
189
190					XSLoader::load 'YourPackage';
191
192					If the call to C<load> is from C<YourPackage>, then that can be further
193					simplified to
194
195					XSLoader::load();
196
197					as C<load> will use C<caller> to determine the package.
198
199					=head2 Backward compatible boilerplate
200
201					If you want to have your cake and eat it too, you need a more complicated
202					boilerplate.
203
204					package YourPackage;
205					use vars qw($VERSION @ISA);
206
207					@ISA = qw( OnePackage OtherPackage );
208					$VERSION = '0.01';
209					eval {
210					require XSLoader;
211					XSLoader::load('YourPackage', $VERSION);
212					1;
213					} or do {
214					require DynaLoader;
215					push @ISA, 'DynaLoader';
216					bootstrap YourPackage $VERSION;
217					};
218
219					The parentheses about C<XSLoader::load()> arguments are needed since we replaced
220					C<use XSLoader> by C<require>, so the compiler does not know that a function
221					C<XSLoader::load()> is present.
222
223					This boilerplate uses the low-overhead C<XSLoader> if present; if used with
224					an antique Perl which has no C<XSLoader>, it falls back to using C<DynaLoader>.
225
226					=head1 Order of initialization: early load()
227
228					I<Skip this section if the XSUB functions are supposed to be called from other
229					modules only; read it only if you call your XSUBs from the code in your module,
230					or have a C<BOOT:> section in your XS file (see L<perlxs/"The BOOT: Keyword">).
231					What is described here is equally applicable to the L<DynaLoader\|DynaLoader>
232					interface.>
233
234					A sufficiently complicated module using XS would have both Perl code (defined
235					in F<YourPackage.pm>) and XS code (defined in F<YourPackage.xs>). If this
236					Perl code makes calls into this XS code, and/or this XS code makes calls to
237					the Perl code, one should be careful with the order of initialization.
238
239					The call to C<XSLoader::load()> (or C<bootstrap()>) calls the module's
240					bootstrap code. For modules build by F<xsubpp> (nearly all modules) this
241					has three side effects:
242
243					=over
244
245					=item *
246
247					A sanity check is done to ensure that the versions of the F<.pm> and the
248					(compiled) F<.xs> parts are compatible. If C<$VERSION> was specified, this
249					is used for the check. If not specified, it defaults to
250					C<$XS_VERSION // $VERSION> (in the module's namespace)
251
252					=item *
253
254					the XSUBs are made accessible from Perl
255
256					=item *
257
258					if a C<BOOT:> section was present in the F<.xs> file, the code there is called.
259
260					=back
261
262					Consequently, if the code in the F<.pm> file makes calls to these XSUBs, it is
263					convenient to have XSUBs installed before the Perl code is defined; for
264					example, this makes prototypes for XSUBs visible to this Perl code.
265					Alternatively, if the C<BOOT:> section makes calls to Perl functions (or
266					uses Perl variables) defined in the F<.pm> file, they must be defined prior to
267					the call to C<XSLoader::load()> (or C<bootstrap()>).
268
269					The first situation being much more frequent, it makes sense to rewrite the
270					boilerplate as
271
272					package YourPackage;
273					use XSLoader;
274					use vars qw($VERSION @ISA);
275
276					BEGIN {
277					@ISA = qw( OnePackage OtherPackage );
278					$VERSION = '0.01';
279
280					# Put Perl code used in the BOOT: section here
281
282					XSLoader::load 'YourPackage', $VERSION;
283					}
284
285					# Put Perl code making calls into XSUBs here
286
287					=head2 The most hairy case
288
289					If the interdependence of your C<BOOT:> section and Perl code is
290					more complicated than this (e.g., the C<BOOT:> section makes calls to Perl
291					functions which make calls to XSUBs with prototypes), get rid of the C<BOOT:>
292					section altogether. Replace it with a function C<onBOOT()>, and call it like
293					this:
294
295					package YourPackage;
296					use XSLoader;
297					use vars qw($VERSION @ISA);
298
299					BEGIN {
300					@ISA = qw( OnePackage OtherPackage );
301					$VERSION = '0.01';
302					XSLoader::load 'YourPackage', $VERSION;
303					}
304
305					# Put Perl code used in onBOOT() function here; calls to XSUBs are
306					# prototype-checked.
307
308					onBOOT;
309
310					# Put Perl initialization code assuming that XS is initialized here
311
312
313					=head1 DIAGNOSTICS
314
315					=over
316
317					=item C<Can't find '%s' symbol in %s>
318
319					B<(F)> The bootstrap symbol could not be found in the extension module.
320
321					=item C<Can't load '%s' for module %s: %s>
322
323					B<(F)> The loading or initialisation of the extension module failed.
324					The detailed error follows.
325
326					=item C<Undefined symbols present after loading %s: %s>
327
328					B<(W)> As the message says, some symbols stay undefined although the
329					extension module was correctly loaded and initialised. The list of undefined
330					symbols follows.
331
332					=back
333
334					=head1 LIMITATIONS
335
336					To reduce the overhead as much as possible, only one possible location
337					is checked to find the extension DLL (this location is where C<make install>
338					would put the DLL). If not found, the search for the DLL is transparently
339					delegated to C<DynaLoader>, which looks for the DLL along the C<@INC> list.
340
341					In particular, this is applicable to the structure of C<@INC> used for testing
342					not-yet-installed extensions. This means that running uninstalled extensions
343					may have much more overhead than running the same extensions after
344					C<make install>.
345
346
347					=head1 KNOWN BUGS
348
349					The new simpler way to call C<XSLoader::load()> with no arguments at all
350					does not work on Perl 5.8.4 and 5.8.5.
351
352
353					=head1 BUGS
354
355					Please report any bugs or feature requests via the perlbug(1) utility.
356
357
358					=head1 SEE ALSO
359
360					L<DynaLoader>
361
362
363					=head1 AUTHORS
364
365					Ilya Zakharevich originally extracted C<XSLoader> from C<DynaLoader>.
366
367					CPAN version is currently maintained by SE<eacute>bastien Aperghis-Tramoni
368					E<lt>[email protected]<gt>.
369
370					Previous maintainer was Michael G Schwern <[email protected]>.
371
372
373					=head1 COPYRIGHT & LICENSE
374
375					Copyright (C) 1990-2011 by Larry Wall and others.
376
377					This program is free software; you can redistribute it and/or modify
378					it under the same terms as Perl itself.
379
380					=cut