Context Navigation

source: driver/cfa.cc @ c19edd1

ADTast-experimentalpthread-emulationqualifiedEnum

Last change on this file since c19edd1 was fcd1a469, checked in by Peter A. Buhr <pabuhr@…>, 3 years ago
formatting, add short form for -XCFA options
Property mode set to `100644`
File size: 19.7 KB

Line
1	//
2	// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
3	//
4	// The contents of this file are covered under the licence agreement in the
5	// file "LICENCE" distributed with Cforall.
6	//
7	// cfa.cc --
8	//
9	// Author : Peter A. Buhr
10	// Created On : Tue Aug 20 13:44:49 2002
11	// Last Modified By : Peter A. Buhr
12	// Last Modified On : Wed Jul 14 21:55:12 2021
13	// Update Count : 467
14	//
15
16	#include <iostream>
17	#include <cstdio> // perror
18	#include <cstdlib> // putenv, exit
19	#include <climits> // PATH_MAX
20	#include <string> // STL version
21	#include <algorithm> // find
22
23	#include <unistd.h> // execvp
24	#include <sys/types.h>
25	#include <sys/stat.h>
26
27	#include "Common/SemanticError.h"
28	#include "config.h" // configure info
29
30	using std::cerr;
31	using std::endl;
32	using std::string;
33	using std::to_string;
34
35	//#define __DEBUG_H__
36
37	#define xstr(s) str(s)
38	#define str(s) #s
39
40	static string __CFA_FLAGPREFIX__( "__CFA_FLAG" ); // "__CFA_FLAG__=" suffix
41
42	static void Putenv( char * argv[], string arg ) {
43	// environment variables must have unique names
44	static int flags = 0;
45
46	if ( putenv( (char )( new string( string( __CFA_FLAGPREFIX__ + to_string( flags++ ) + "__=" ) + arg ) ).c_str() ) ) {
47	cerr << argv[0] << " error, cannot set environment variable." << endl;
48	exit( EXIT_FAILURE );
49	} // if
50	} // Putenv
51
52	static bool prefix( const string & arg, const string & pre ) { // check if string has prefix
53	return arg.substr( 0, pre.size() ) == pre;
54	} // prefix
55
56	static inline bool ends_with(const string & str, const string & sfix) {
57	if (sfix.size() > str.size()) return false;
58	return std::equal(str.rbegin(), str.rbegin() + sfix.size(), sfix.rbegin(), sfix.rend());
59	}
60
61	// check if string has suffix
62	static bool suffix( const string & arg ) {
63	enum { NumSuffixes = 3 };
64	static const string suffixes[NumSuffixes] = { "cfa", "hfa", "ifa" };
65
66	size_t dot = arg.find_last_of( "." );
67	if ( dot == string::npos ) return false;
68	const string * end = suffixes + NumSuffixes;
69	return std::find( suffixes, end, arg.substr( dot + 1 ) ) != end;
70	} // suffix
71
72	static inline bool dirExists( const string & path ) { // check if directory exists
73	struct stat info;
74	if ( stat( path.c_str(), &info ) != 0 ) return false;
75	return (info.st_mode & S_IFDIR) != 0;
76	} // dirExists
77
78	static inline string dir(const string & path) {
79	return path.substr(0, path.find_last_of('/'));
80	} // dir
81
82	// Different path modes
83	enum PathMode {
84	Installed, // cfa is installed, use prefix
85	BuildTree, // cfa is in the tree, use source and build tree
86	Distributed // cfa is distributed, use build tree for includes and executable directory for .cfs
87	};
88
89	// Get path mode from /proc
90	PathMode FromProc() {
91	std::string abspath;
92	abspath.resize(PATH_MAX);
93
94	// get executable path from /proc/self/exe
95	ssize_t size = readlink("/proc/self/exe", const_cast<char*>(abspath.c_str()), abspath.size());
96	if ( size <= 0 ) {
97	std::cerr << "Error could not evaluate absolute path from /proc/self/exe" << std::endl;
98	std::cerr << "Failed with " << std::strerror(errno) << std::endl;
99	std::exit(1);
100	} // if
101
102	// Trim extra characters
103	abspath.resize(size);
104
105	// Are we installed
106	if ( abspath.rfind(CFA_BINDIR, 0) == 0 ) { return Installed; }
107
108	// Is this the build tree
109	if ( abspath.rfind(TOP_BUILDDIR, 0 ) == 0 ) { return BuildTree; }
110
111	// Does this look like distcc
112	if ( abspath.find( "/.cfadistcc/" ) != std::string::npos ) { return Distributed; }
113
114	// None of the above? Give up since we don't know where the prelude or include directories are
115	std::cerr << "Cannot find required files from excutable path " << abspath << std::endl;
116	std::exit(1);
117	}
118
119
120	int main( int argc, char * argv[] ) {
121	string Version( CFA_VERSION_LONG ); // current version number from CONFIG
122	string Major( xstr( CFA_VERSION_MAJOR ) ), Minor( xstr( CFA_VERSION_MINOR ) ), Patch( xstr( CFA_VERSION_PATCH ) );
123
124	string installincdir( CFA_INCDIR ); // fixed location of include files
125	string installlibdir( CFA_LIBDIR ); // fixed location of cc1 and cfa-cpp commands when installed
126	string srcdriverdir ( TOP_BUILDDIR "driver"); // fixed location of cc1 and cfa-cpp commands when in tree
127
128	string heading; // banner printed at start of cfa compilation
129	string arg; // current command-line argument during command-line parsing
130	string bprefix; // path where gcc looks for compiler steps
131	string langstd; // language standard
132
133	string compiler_path( CFA_BACKEND_CC ); // path/name of C compiler
134	string compiler_name; // name of C compiler
135
136	bool x_flag = false; // -x flag
137	bool nonoptarg = false; // no non-option arguments specified, i.e., no file names
138	bool link = true; // link stage occurring
139	bool verbose = false; // -v flag
140	bool quiet = false; // -quiet flag
141	bool debug = true; // -debug flag
142	bool nolib = false; // -nolib flag
143	bool help = false; // -help flag
144	bool CFA_flag = false; // -CFA flag
145	bool cpp_flag = false; // -E or -M flag, preprocessor only
146	bool std_flag = false; // -std= flag
147	bool noincstd_flag = false; // -no-include-stdhdr= flag
148	bool debugging __attribute(( unused )) = false; // -g flag
149	bool m32 = false; // -m32 flag
150	bool m64 = false; // -m64 flag
151	bool compiling_libs = false;
152	int o_file = 0; // -o filename position
153
154	PathMode path = FromProc();
155
156	const char * args[argc + 100]; // cfa command line values, plus some space for additional flags
157	int sargs = 1; // starting location for arguments in args list
158	int nargs = sargs; // number of arguments in args list; 0 => command name
159
160	const char * libs[argc + 20]; // non-user libraries must come separately, plus some added libraries and flags
161	int nlibs = 0;
162
163	#ifdef __DEBUG_H__
164	cerr << "CFA:" << endl;
165	for ( int i = 1; i < argc; i += 1 ) {
166	cerr << "argv[" << i << "]:\"" << argv[i] << "\"" << endl;
167	} // for
168	#endif // __DEBUG_H__
169
170	// process command-line arguments
171
172	for ( int i = 1; i < argc; i += 1 ) {
173	arg = argv[i]; // convert to string value
174	if ( prefix( arg, "-" ) ) {
175	// pass through arguments
176
177	if ( arg == "-Xlinker" \|\| arg == "-o" ) {
178	args[nargs++] = argv[i]; // pass flag along
179	i += 1;
180	if ( i == argc ) continue; // next argument available ?
181	args[nargs++] = argv[i]; // pass argument along
182	if ( arg == "-o" ) o_file = i; // remember file
183
184	// CFA specific arguments
185
186	} else if ( strncmp(arg.c_str(), "-XCFA", 5) == 0 ) { // CFA pass through
187	if ( arg.size() == 5 ) {
188	i += 1;
189	if ( i == argc ) continue; // next argument available ?
190	Putenv( argv, argv[i] ); // make available for cc1
191	} else if ( arg[5] == ',' ) { // CFA specific arguments
192	string xcfargs = arg.substr( 6 ) + ","; // add sentinel
193	for ( ;; ) {
194	size_t posn = xcfargs.find_first_of( "," ); // find separator
195	if ( posn == string::npos ) break; // any characters left ?
196	string xcfarg = xcfargs.substr( 0, posn ); // remove XCFA argument
197	Putenv( argv, xcfarg ); // make available for cc1
198	xcfargs.erase( 0, posn + 1 ); // remove first argument and comma
199	} // for
200	} else { // CFA specific arguments
201	assert( false ); // this does not make sense
202	args[nargs++] = argv[i];
203	} // if
204	} else if ( arg == "-CFA" ) {
205	CFA_flag = true; // strip the -CFA flag
206	link = false;
207	args[nargs++] = "-fsyntax-only"; // stop after stage 2
208	} else if ( arg == "-debug" ) {
209	debug = true; // strip the debug flag
210	} else if ( arg == "-nodebug" ) {
211	debug = false; // strip the nodebug flag
212	} else if ( arg == "-quiet" ) {
213	quiet = true; // strip the quiet flag
214	} else if ( arg == "-noquiet" ) {
215	quiet = false; // strip the noquiet flag
216	} else if ( arg == "-no-include-stdhdr" ) {
217	noincstd_flag = true; // strip the no-include-stdhdr flag
218	} else if ( arg == "-nolib" ) {
219	nolib = true; // strip the nolib flag
220	} else if ( arg == "-help" ) {
221	help = true; // strip the help flag
222	} else if ( arg == "-nohelp" ) {
223	help = false; // strip the nohelp flag
224	} else if ( arg == "-cfalib") {
225	compiling_libs = true;
226	} else if ( arg == "-compiler" ) {
227	// use the user specified compiler
228	i += 1;
229	if ( i == argc ) continue; // next argument available ?
230	compiler_path = argv[i];
231	Putenv( argv, arg + "=" + argv[i] );
232
233	// C specific arguments
234
235	} else if ( arg == "-v" ) {
236	verbose = true; // verbosity required
237	args[nargs++] = argv[i]; // pass flag along
238	} else if ( arg == "-g" ) {
239	debugging = true; // symbolic debugging required
240	args[nargs++] = argv[i]; // pass flag along
241	} else if ( arg == "-save-temps" \|\| arg == "--save-temps" ) {
242	args[nargs++] = argv[i]; // pass flag along
243	Putenv( argv, arg ); // save cfa-cpp output
244	} else if ( prefix( arg, "-x" ) ) { // file suffix ?
245	string lang;
246	args[nargs++] = argv[i]; // pass flag along
247	if ( arg.length() == 2 ) { // separate argument ?
248	i += 1;
249	if ( i == argc ) continue; // next argument available ?
250	lang = argv[i];
251	args[nargs++] = argv[i]; // pass argument along
252	} else {
253	lang = arg.substr( 2 );
254	} // if
255	if ( x_flag ) {
256	cerr << argv[0] << " warning, only one -x flag per compile, ignoring subsequent flag." << endl;
257	} else {
258	x_flag = true;
259	Putenv( argv, string( "-x=" ) + lang );
260	} // if
261	} else if ( prefix( arg, "-std=" ) \|\| prefix( arg, "--std=" ) ) {
262	std_flag = true; // -std=XX provided
263	args[nargs++] = argv[i]; // pass flag along
264	} else if ( arg == "-w" ) {
265	args[nargs++] = argv[i]; // pass flag along
266	Putenv( argv, arg );
267	} else if ( prefix( arg, "-W" ) ) { // check before next tests
268	if ( arg == "-Werror" \|\| arg == "-Wall" ) {
269	args[nargs++] = argv[i]; // pass flag along
270	Putenv( argv, argv[i] );
271	} else {
272	unsigned int adv = prefix( arg, "-Wno-" ) ? 5 : 2;
273	args[nargs] = argv[i]; // conditionally pass argument along
274	const char * warning = argv[i] + adv; // extract warning
275	if ( SemanticWarning_Exist( warning ) ) { // replace the argument for cfa-cpp
276	Putenv( argv, arg );
277	} // if
278	nargs += 1;
279	} // if
280	} else if ( prefix( arg, "-B" ) ) {
281	bprefix = arg.substr(2); // strip the -B flag
282	} else if ( arg == "-c" \|\| arg == "-S" \|\| arg == "-E" \|\| arg == "-M" \|\| arg == "-MM" ) {
283	args[nargs++] = argv[i]; // pass flag along
284	if ( arg == "-E" \|\| arg == "-M" \|\| arg == "-MM" ) {
285	cpp_flag = true; // cpp only
286	} // if
287	link = false; // no linkage required
288	} else if ( arg == "-D" \|\| arg == "-U" \|\| arg == "-I" \|\| arg == "-MF" \|\| arg == "-MT" \|\| arg == "-MQ" \|\|
289	arg == "-include" \|\| arg == "-imacros" \|\| arg == "-idirafter" \|\| arg == "-iprefix" \|\|
290	arg == "-iwithprefix" \|\| arg == "-iwithprefixbefore" \|\| arg == "-isystem" \|\| arg == "-isysroot" ) {
291	args[nargs++] = argv[i]; // pass flag along
292	i += 1;
293	args[nargs++] = argv[i]; // pass argument along
294	} else if ( arg[1] == 'l' ) {
295	// if the user specifies a library, load it after user code
296	libs[nlibs++] = argv[i];
297	} else if ( arg == "-m32" ) {
298	m32 = true;
299	m64 = false;
300	args[nargs++] = argv[i];
301	} else if ( arg == "-m64" ) {
302	m64 = true;
303	m32 = false;
304	args[nargs++] = argv[i];
305	} else {
306	// concatenate any other arguments
307	args[nargs++] = argv[i];
308	} // if
309	} else {
310	bool cfa = suffix( arg ); // check suffix
311	if ( ! x_flag && cfa ) { // no explicit suffix and cfa suffix ?
312	args[nargs++] = "-x";
313	args[nargs++] = "c";
314	} // if
315	args[nargs++] = argv[i]; // concatenate files
316	if ( ! x_flag && cfa ) { // no explicit suffix and cfa suffix ?
317	args[nargs++] = "-x";
318	args[nargs++] = "none";
319	} // if
320	nonoptarg = true;
321	} // if
322	} // for
323
324	#ifdef __x86_64__
325	args[nargs++] = "-mcx16"; // allow double-wide CAS
326	#endif // __x86_64__
327
328	#ifdef __DEBUG_H__
329	cerr << "args:";
330	for ( int i = 1; i < nargs; i += 1 ) {
331	cerr << " " << args[i];
332	} // for
333	cerr << endl;
334	#endif // __DEBUG_H__
335
336	// -E flag stops at cc1 stage 1, so cfa-cpp in cc1 stage 2 is never executed.
337	if ( cpp_flag && CFA_flag ) {
338	CFA_flag = false;
339	cerr << argv[0] << " warning, both -E and -CFA flags specified, using -E and ignoring -CFA." << endl;
340	} // if
341
342	// add the CFA include-library paths, which allow direct access to header files without directory qualification
343	string libbase;
344	switch(path) {
345	case Installed:
346	args[nargs++] = "-I" CFA_INCDIR;
347	// do not use during build
348	if ( ! noincstd_flag ) {
349	args[nargs++] = "-I" CFA_INCDIR "stdhdr";
350	} // if
351	args[nargs++] = "-I" CFA_INCDIR "concurrency";
352	args[nargs++] = "-I" CFA_INCDIR "containers";
353	libbase = CFA_LIBDIR;
354	break;
355	case BuildTree:
356	case Distributed:
357	args[nargs++] = "-I" TOP_SRCDIR "libcfa/src";
358	// do not use during build
359	if ( ! noincstd_flag ) {
360	args[nargs++] = "-I" TOP_SRCDIR "libcfa/src" "/stdhdr";
361	} // if
362	args[nargs++] = "-I" TOP_SRCDIR "libcfa/src" "/concurrency";
363	args[nargs++] = "-I" TOP_SRCDIR "libcfa/src" "/containers";
364
365	libbase = TOP_BUILDDIR "libcfa/";
366
367	break;
368	} // if
369
370	// add stdbool to get defines for bool/true/false
371	args[nargs++] = "-imacros";
372	args[nargs++] = "stdbool.h";
373
374	if ( compiling_libs ) {
375	Putenv( argv, "-t" );
376	} // if
377
378	string arch( m32 ? CFA_32_CPU : (m64 ? CFA_64_CPU : CFA_DEFAULT_CPU) );
379	if ( ! m32 && ! m64 ) {
380	if ( arch == "x86" ) {
381	args[nargs++] = "-m32";
382	} else if ( arch == "x64" ) {
383	args[nargs++] = "-m64";
384	} // if
385	} // if
386
387	const char * config = nolib ? "nolib" : (debug ? "debug": "nodebug");
388	string libdir = libbase + arch + "-" + config;
389
390	if ( path != Distributed ) {
391	if ( ! nolib && ! dirExists( libdir ) ) {
392	cerr << argv[0] << " internal error, configuration " << config << " not installed." << endl;
393	cerr << "Was looking for " << libdir << endl;
394	for(int i = 1; i < argc; i++) {
395	cerr << argv[i] << " ";
396	}
397	cerr << endl;
398	libdir = libbase + arch + "-" + "nolib";
399	} // if
400
401	if ( ! dirExists( libdir ) ) {
402	cerr << argv[0] << " internal error, cannot find prelude directory." << endl;
403	cerr << "Was looking for " << libdir << endl;
404	exit( EXIT_FAILURE );
405	} // if
406	} // if
407
408	string preludedir;
409	switch(path) {
410	case Installed : preludedir = libdir; break;
411	case BuildTree : preludedir = libdir + "/prelude"; break;
412	case Distributed : preludedir = dir(argv[0]); break;
413	} // switch
414
415	Putenv( argv, "--prelude-dir=" + preludedir );
416	args[nargs++] = "-include";
417	args[nargs++] = (*new string(preludedir + "/defines.hfa")).c_str();
418
419	for ( int i = 0; i < nlibs; i += 1 ) { // copy non-user libraries after all user libraries
420	args[nargs++] = libs[i];
421	} // for
422
423	if ( link ) {
424	args[nargs++] = "-Xlinker";
425	args[nargs++] = "--undefined=__cfaabi_dbg_bits_write";
426	args[nargs++] = "-Xlinker";
427	args[nargs++] = "--undefined=__cfaabi_interpose_startup";
428	args[nargs++] = "-Xlinker";
429	args[nargs++] = "--undefined=__cfaabi_appready_startup";
430	args[nargs++] = "-z";
431	args[nargs++] = "execstack";
432
433	// include the cfa library in case it is needed
434	args[nargs++] = ( *new string( string("-L" ) + libdir + (path != Installed ? "/src/.libs" : "")) ).c_str();
435	args[nargs++] = ( *new string( string("-Wl,-rpath," ) + libdir + (path != Installed ? "/src/.libs" : "")) ).c_str();
436	args[nargs++] = "-Wl,--push-state,--as-needed";
437	args[nargs++] = "-lcfathread";
438	args[nargs++] = "-Wl,--pop-state";
439	args[nargs++] = "-Wl,--push-state,--no-as-needed";
440	args[nargs++] = "-lcfa";
441	args[nargs++] = "-Wl,--pop-state";
442	args[nargs++] = "-pthread";
443	#if defined( __x86_64__ ) \|\| defined( __ARM_ARCH )
444	args[nargs++] = "-latomic"; // allow double-wide CAS
445	#endif // __x86_64__
446	args[nargs++] = "-ldl";
447	args[nargs++] = "-lm";
448	} // if
449
450	args[nargs++] = "-fexceptions"; // add exception flags (unconditionally)
451
452	// add flags based on the type of compile
453
454	args[nargs++] = ( *new string( string("-D__CFA_MAJOR__=") + Major ) ).c_str();
455	args[nargs++] = ( *new string( string("-D__CFA_MINOR__=") + Minor ) ).c_str();
456	args[nargs++] = ( *new string( string("-D__CFA_PATCH__=") + Patch ) ).c_str();
457	args[nargs++] = "-D__CFA__";
458	args[nargs++] = "-D__CFORALL__";
459	args[nargs++] = "-D__cforall";
460
461	if ( cpp_flag ) {
462	args[nargs++] = "-D__CPP__";
463	} // if
464
465	if ( CFA_flag ) {
466	Putenv( argv, "-N" );
467	Putenv( argv, "-CFA" );
468	// -CFA implies cc1 stage 2, but gcc does not pass the -o file to this stage because it believe the file is for
469	// the linker. Hence, the -o file is explicit passed to cc1 stage 2 and used as cfa-cpp's output file.
470	if ( o_file ) Putenv( argv, string( "-o=" ) + argv[o_file] );
471	} else {
472	Putenv( argv, "-L" );
473	} // if
474
475	if ( debug ) {
476	heading += " (debug)";
477	args[nargs++] = "-D__CFA_DEBUG__";
478	} else {
479	heading += " (no debug)";
480	} // if
481
482	if ( bprefix.length() == 0 ) {
483	switch(path) {
484	case Installed : bprefix = installlibdir; break;
485	case BuildTree : bprefix = srcdriverdir ; break;
486	case Distributed : bprefix = dir(argv[0]) ; break;
487	} // switch
488	} // if
489	if ( bprefix[bprefix.length() - 1] != '/' ) bprefix += '/';
490	Putenv( argv, string("-B=") + bprefix );
491
492	args[nargs++] = "-Xlinker"; // used by backtrace
493	args[nargs++] = "-export-dynamic";
494
495	// execute the compilation command
496
497	args[0] = compiler_path.c_str(); // set compiler command for exec
498	// find actual name of the compiler independent of the path to it
499	int p = compiler_path.find_last_of( '/' ); // scan r -> l for first '/'
500	if ( p == -1 ) {
501	compiler_name = compiler_path;
502	} else {
503	compiler_name = *new string( compiler_path.substr( p + 1 ) );
504	} // if
505
506	if ( prefix( compiler_name, "gcc" ) ) { // allow suffix on gcc name
507	args[nargs++] = "-no-integrated-cpp";
508	args[nargs++] = "-Wno-deprecated";
509	args[nargs++] = "-Wno-strict-aliasing"; // casting from one type to another
510	#ifdef HAVE_CAST_FUNCTION_TYPE
511	args[nargs++] = "-Wno-cast-function-type";
512	#endif // HAVE_CAST_FUNCTION_TYPE
513	if ( ! std_flag && ! x_flag ) {
514	args[nargs++] = "-std=gnu11"; // default c11, if none specified
515	} // if
516	args[nargs++] = "-fgnu89-inline";
517	args[nargs++] = "-D__int8_t_defined"; // prevent gcc type-size attributes
518	args[nargs++] = ( *new string( string("-B") + bprefix ) ).c_str();
519	} else {
520	cerr << argv[0] << " error, compiler \"" << compiler_name << "\" unsupported." << endl;
521	exit( EXIT_FAILURE );
522	} // if
523
524	args[nargs] = nullptr; // terminate
525
526	#ifdef __DEBUG_H__
527	cerr << "nargs: " << nargs << endl;
528	cerr << "args:" << endl;
529	for ( int i = 0; args[i] != nullptr; i += 1 ) {
530	cerr << " \"" << args[i] << "\"" << endl;
531	} // for
532	cerr << endl;
533	#endif // __DEBUG_H__
534
535	if ( ! quiet ) {
536	cerr << "CFA " << "Version " << Version << heading << endl;
537	if ( help ) {
538	cerr <<
539	"-debug\t\t\t: use cfa runtime with debug checking" << endl <<
540	"-help\t\t\t: print this help message" << endl <<
541	"-quiet\t\t\t: print no messages from the cfa command" << endl <<
542	"-CFA\t\t\t: run the cpp preprocessor and the cfa-cpp translator" << endl <<
543	"-XCFA -cfa-cpp-flag\t: pass next flag as-is to the cfa-cpp translator" << endl <<
544	"...\t\t\t: any other " << compiler_name << " flags" << endl;
545	} // if
546	} // if
547
548	if ( verbose ) {
549	if ( argc == 2 ) exit( EXIT_SUCCESS ); // if only the -v flag is specified, do not invoke gcc
550
551	for ( int i = 0; args[i] != nullptr; i += 1 ) {
552	cerr << args[i] << " ";
553	} // for
554	cerr << endl;
555	} // if
556
557	if ( ! nonoptarg ) {
558	cerr << argv[0] << " error, no input files" << endl;
559	exit( EXIT_FAILURE );
560	} // if
561
562	// execute the command and return the result
563
564	execvp( args[0], (char * const *)args ); // should not return
565	perror( "CFA Translator error: execvp" );
566	exit( EXIT_FAILURE );
567	} // main
568
569	// Local Variables: //
570	// tab-width: 4 //
571	// mode: c++ //
572	// compile-command: "make install" //
573	// End: //

Note: See TracBrowser for help on using the repository browser.

Download in other formats: