OpenCores
URL https://opencores.org/ocsvn/openrisc/openrisc/trunk

Subversion Repositories openrisc

[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [gcc/] [ONEWS] - Blame information for rev 745

Go to most recent revision | Details | Compare with Previous | View Log

Line No. Rev Author Line
1 684 jeremybenn
This file contains information about GCC releases up to GCC 2.8.1, and
2
a tiny bit of information on EGCS.
3
 
4
For details of changes in EGCS releases and GCC 2.95 and later releases,
5
see the release notes on the GCC web site or the file NEWS which contains
6
the most relevant parts of those release notes in text form.
7
 
8
Changes in GCC for EGCS (that are not listed in the web release notes)
9
---------------------------------------------------------------------
10
 
11
The compiler now supports the "ADDRESSOF" optimization which can significantly
12
reduce the overhead for certain inline calls (and inline calls in general).
13
 
14
Compile time for certain programs using large constant initializers has been
15
improved (affects glibc significantly).
16
 
17
Various improvements have been made to better support cross compilations.  They
18
are still not easy, but they are improving.
19
 
20
Target-specific changes:
21
 
22
    M32r: Major improvements to this port.
23
 
24
    Arm: Includes Thumb and super interworking support.
25
 
26
Noteworthy changes in GCC version 2.8.1
27
---------------------------------------
28
 
29
Numerous bugs have been fixed and some minor performance
30
improvements (compilation speed) have been made.
31
 
32
Noteworthy changes in GCC version 2.8.0
33
---------------------------------------
34
 
35
A major change in this release is the addition of a framework for
36
exception handling, currently used by C++.  Many internal changes and
37
optimization improvements have been made.  These increase the
38
maintainability and portability of GCC.  GCC now uses autoconf to
39
compute many host parameters.
40
 
41
The following lists changes that add new features or targets.
42
 
43
See cp/NEWS for new features of C++ in this release.
44
 
45
New tools and features:
46
 
47
    The Dwarf 2 debugging information format is supported on ELF systems, and
48
    is the default for -ggdb where available.  It can also be used for C++.
49
    The Dwarf version 1 debugging format is also permitted for C++, but
50
    does not work well.
51
 
52
    gcov.c is provided for test coverage analysis and branch profiling
53
    analysis is also supported; see -fprofile-arcs, -ftest-coverage,
54
    and -fbranch-probabilities.
55
 
56
    Support for the Checker memory checking tool.
57
 
58
    New switch, -fstack-check, to check for stack overflow on systems that
59
    don't have such built into their ABI.
60
 
61
    New switches, -Wundef and -Wno-undef to warn if an undefined identifier
62
    is evaluated in an #if directive.
63
 
64
    Options -Wall and -Wimplicit now cause GCC to warn about implicit int
65
    in declarations (e.g. `register i;'), since the C Standard committee
66
    has decided to disallow this in the next revision of the standard;
67
    -Wimplicit-function-declarations and -Wimplicit-int are subsets of
68
    this.
69
 
70
    Option -Wsign-compare causes GCC to warn about comparison of signed and
71
    unsigned values.
72
 
73
    Add -dI option of cccp for cxref.
74
 
75
New features in configuration, installation and specs file handling:
76
 
77
    New option --enable-c-cpplib to configure script.
78
 
79
    You can use --with-cpu on the configure command to specify the default
80
    CPU that GCC should generate code for.
81
 
82
    The -specs=file switch allows you to override default specs used in
83
    invoking programs like cc1, as, etc.
84
 
85
    Allow including one specs file from another and renaming a specs
86
    variable.
87
 
88
    You can now relocate all GCC files with a single environment variable
89
    or a registry entry under Windows 95 and Windows NT.
90
 
91
Changes in Objective-C:
92
 
93
    The Objective-C Runtime Library has been made thread-safe.
94
 
95
    The Objective-C Runtime Library contains an interface for creating
96
    mutexes, condition mutexes, and threads; it requires a back-end
97
    implementation for the specific platform and/or thread package.
98
    Currently supported are DEC/OSF1, IRIX, Mach, OS/2, POSIX, PCThreads,
99
    Solaris, and Windows32.  The --enable-threads parameter can be used
100
    when configuring GCC to enable and select a thread back-end.
101
 
102
    Objective-C is now configured as separate front-end language to GCC,
103
    making it more convenient to conditionally build it.
104
 
105
    The internal structures of the Objective-C Runtime Library have
106
    changed sufficiently to warrant a new version number; now version 8.
107
    Programs compiled with an older version must be recompiled.
108
 
109
    The Objective-C Runtime Library can be built as a DLL on Windows 95
110
    and Windows NT systems.
111
 
112
    The Objective-C Runtime Library implements +load.
113
 
114
The following new targets are supported (see also list under each
115
individual CPU below):
116
 
117
    Embedded target m32r-elf.
118
    Embedded Hitachi Super-H using ELF.
119
    RTEMS real-time system on various CPU targets.
120
    ARC processor.
121
    NEC V850 processor.
122
    Matsushita MN10200 processor.
123
    Matsushita MN10300 processor.
124
    Sparc and PowerPC running on VxWorks.
125
    Support both glibc versions 1 and 2 on Linux-based GNU systems.
126
 
127
New features for DEC Alpha systems:
128
 
129
    Allow detailed specification of IEEE fp support:
130
      -mieee, -mieee-with-inexact, and -mieee-conformant
131
      -mfp-trap-mode=xxx, -mfp-round-mode=xxx, -mtrap-precision=xxx
132
    -mcpu=xxx for CPU selection
133
    Support scheduling parameters for EV5.
134
    Add support for BWX, CIX, and MAX instruction set extensions.
135
    Support Linux-based GNU systems.
136
    Support VMS.
137
 
138
Additional supported processors and systems for MIPS targets:
139
 
140
    MIPS4 instruction set.
141
    R4100, R4300 and R5000 processors.
142
    N32 and N64 ABI.
143
    IRIX 6.2.
144
    SNI SINIX.
145
 
146
New features for Intel x86 family:
147
 
148
    Add scheduling parameters for Pentium and Pentium Pro.
149
    Support stabs on Solaris-x86.
150
    Intel x86 processors running the SCO OpenServer 5 family.
151
    Intel x86 processors running DG/UX.
152
    Intel x86 using Cygwin32 or Mingw32 on Windows 95 and Windows NT.
153
 
154
New features for Motorola 68k family:
155
 
156
    Support for 68060 processor.
157
    More consistent switches to specify processor.
158
    Motorola 68k family running AUX.
159
    68040 running pSOS, ELF object files, DBX debugging.
160
    Coldfire variant of Motorola m68k family.
161
 
162
New features for the HP PA RISC:
163
 
164
    -mspace and -mno-space
165
    -mlong-load-store and -mno-long-load-store
166
    -mbig-switch -mno-big-switch
167
 
168
    GCC on the PA requires either gas-2.7 or the HP assembler; for best
169
    results using GAS is highly recommended.  GAS is required for -g and
170
    exception handling support.
171
 
172
New features for SPARC-based systems:
173
 
174
    The ultrasparc cpu.
175
    The sparclet cpu, supporting only a.out file format.
176
    Sparc running SunOS 4 with the GNU assembler.
177
    Sparc running the Linux-based GNU system.
178
    Embedded Sparc processors running the ELF object file format.
179
    -mcpu=xxx
180
    -mtune=xxx
181
    -malign-loops=xxx
182
    -malign-jumps=xxx
183
    -malign-functions=xxx
184
    -mimpure-text and -mno-impure-text
185
 
186
    Options -mno-v8 and -mno-sparclite are no longer supported on SPARC
187
    targets.  Options -mcypress, -mv8, -msupersparc, -msparclite, -mf930,
188
    and -mf934 are deprecated and will be deleted in GCC 2.9.  Use
189
    -mcpu=xxx instead.
190
 
191
New features for rs6000 and PowerPC systems:
192
 
193
    Solaris 2.51 running on PowerPC's.
194
    The Linux-based GNU system running on PowerPC's.
195
    -mcpu=604e,602,603e,620,801,823,mpc505,821,860,power2
196
    -mtune=xxx
197
    -mrelocatable-lib, -mno-relocatable-lib
198
    -msim, -mmve, -memb
199
    -mupdate, -mno-update
200
    -mfused-madd, -mno-fused-madd
201
 
202
    -mregnames
203
    -meabi
204
    -mcall-linux, -mcall-solaris, -mcall-sysv-eabi, -mcall-sysv-noeabi
205
    -msdata, -msdata=none, -msdata=default, -msdata=sysv, -msdata=eabi
206
    -memb, -msim, -mmvme
207
    -myellowknife, -mads
208
    wchar_t is now of type long as per the ABI, not unsigned short.
209
    -p/-pg support
210
    -mcpu=403 now implies -mstrict-align.
211
    Implement System V profiling.
212
 
213
    Aix 4.1 GCC targets now default to -mcpu=common so that programs
214
    compiled can be moved between rs6000 and powerpc based systems.  A
215
    consequence of this is that -static won't work, and that some programs
216
    may be slightly slower.
217
 
218
    You can select the default value to use for -mcpu=xxx on rs6000 and
219
    powerpc targets by using the --with-cpu=xxx option when configuring the
220
    compiler.  In addition, a new options, -mtune=xxx was added that
221
    selects the machine to schedule for but does not select the
222
    architecture level.
223
 
224
    Directory names used for storing the multilib libraries on System V
225
    and embedded PowerPC systems have been shortened to work with commands
226
    like tar that have fixed limits on pathname size.
227
 
228
New features for the Hitachi H8/300(H):
229
 
230
    -malign-300
231
    -ms (for the Hitachi H8/S processor)
232
    -mint32
233
 
234
New features for the ARM:
235
 
236
    -march=xxx, -mtune=xxx, -mcpu=xxx
237
    Support interworking with Thumb code.
238
    ARM processor with a.out object format, COFF, or AOF assembler.
239
    ARM on "semi-hosted" platform.
240
    ARM running NetBSD.
241
    ARM running the Linux-based GNU system.
242
 
243
New feature for Solaris systems:
244
 
245
    GCC installation no longer makes a copy of system include files,
246
    thus insulating GCC better from updates to the operating system.
247
 
248
 
249
Noteworthy changes in GCC version 2.7.2
250
---------------------------------------
251
 
252
A few bugs have been fixed (most notably the generation of an
253
invalid assembler opcode on some RS/6000 systems).
254
 
255
Noteworthy changes in GCC version 2.7.1
256
---------------------------------------
257
 
258
This release fixes numerous bugs (mostly minor) in GCC 2.7.0, but
259
also contains a few new features, mostly related to specific targets.
260
 
261
Major changes have been made in code to support Windows NT.
262
 
263
The following new targets are supported:
264
 
265
        2.9 BSD on PDP-11
266
        Linux on m68k
267
        HP/UX version 10 on HP PA RISC (treated like version 9)
268
        DEC Alpha running Windows NT
269
 
270
When parsing C, GCC now recognizes C++ style `//' comments unless you
271
specify `-ansi' or `-traditional'.
272
 
273
The PowerPC System V targets (powerpc-*-sysv, powerpc-*-eabi) now use the
274
calling sequence specified in the System V Application Binary Interface
275
Processor Supplement (PowerPC Processor ABI Supplement) rather than the calling
276
sequence used in GCC version 2.7.0.  That calling sequence was based on the AIX
277
calling sequence without function descriptors.  To compile code for that older
278
calling sequence, either configure the compiler for powerpc-*-eabiaix or use
279
the -mcall-aix switch when compiling and linking.
280
 
281
Noteworthy changes in GCC version 2.7.0
282
---------------------------------------
283
 
284
GCC now works better on systems that use ".obj" and ".exe" instead of
285
".o" and no extension.  This involved changes to the driver program,
286
gcc.c, to convert ".o" names to ".obj" and to GCC's Makefile to use
287
".obj" and ".exe" in filenames that are not targets.  In order to
288
build GCC on such systems, you may need versions of GNU make and/or
289
compatible shells.  At this point, this support is preliminary.
290
 
291
Object file extensions of ".obj" and executable file extensions of
292
".exe" are allowed when using appropriate version of GNU Make.
293
 
294
Numerous enhancements were made to the __attribute__ facility including
295
more attributes and more places that support it.  We now support the
296
"packed", "nocommon", "noreturn", "volatile", "const", "unused",
297
"transparent_union", "constructor", "destructor", "mode", "section",
298
"align", "format", "weak", and "alias" attributes.  Each of these
299
names may also be specified with added underscores, e.g., "__packed__".
300
__attribute__ may now be applied to parameter definitions, function
301
definitions, and structure, enum, and union definitions.
302
 
303
GCC now supports returning more structures in registers, as specified by
304
many calling sequences (ABIs), such as on the HP PA RISC.
305
 
306
A new option '-fpack-struct' was added to automatically pack all structure
307
members together without holes.
308
 
309
There is a new library (cpplib) and program (cppmain) that at some
310
point will replace cpp (aka cccp).  To use cppmain as cpp now, pass
311
the option CCCP=cppmain to make.  The library is already used by the
312
fix-header program, which should speed up the fixproto script.
313
 
314
New options for supported targets:
315
 
316
    GNU on many targets.
317
    NetBSD on MIPS, m68k, VAX, and x86.
318
    LynxOS on x86, m68k, Sparc, and RS/6000.
319
    VxWorks on many targets.
320
 
321
    Windows/NT on x86 architecture.  Initial support for Windows/NT on Alpha
322
    (not fully working).
323
 
324
    Many embedded targets, specifically UDI on a29k, aout, coff, elf,
325
    and vsta "operating systems" on m68k, m88k, mips, sparc, and x86.
326
 
327
Additional support for x86 (i386, i486, and Pentium):
328
 
329
    Work with old and new linkers for Linux-based GNU systems,
330
        supporting both a.out and ELF.
331
    FreeBSD on x86.
332
    Stdcall convention.
333
    -malign-double, -mregparm=, -malign-loops= and -malign-jumps=  switches.
334
    On ISC systems, support -Xp like -posix.
335
 
336
Additions for RS/6000:
337
 
338
    Instruction scheduling information for PowerPC 403.
339
    AIX 4.1 on PowerPC.
340
    -mstring and -mno-string.
341
    -msoft-float and floating-point emulation included.
342
    Preliminary support for PowerPC System V.4 with or without the GNU as.
343
    Preliminary support for EABI.
344
    Preliminary support for 64-bit systems.
345
    Both big and little endian systems.
346
 
347
New features for MIPS-based systems:
348
 
349
    r4650.
350
    mips4 and R8000.
351
    Irix 6.0.
352
    64-bit ABI.
353
    Allow dollar signs in labels on SGI/Irix 5.x.
354
 
355
New support for HP PA RISC:
356
 
357
    Generation of PIC (requires binutils-2.5.2.u6 or later).
358
    HP-UX version 9 on HP PA RISC (dynamically links even with -g).
359
    Processor variants for HP PA RISC: 700, 7100, and 7100LC.
360
    Automatic generation of long calls when needed.
361
    -mfast-indirect-calls for kernels and static binaries.
362
 
363
    The called routine now copies arguments passed by invisible reference,
364
    as required by the calling standard.
365
 
366
Other new miscellaneous target-specific support:
367
 
368
    -mno-multm on a29k.
369
    -mold-align for i960.
370
    Configuration for "semi-hosted" ARM.
371
    -momit-leaf-frame-pointer for M88k.
372
    SH3 variant of Hitachi Super-H and support both big and little endian.
373
 
374
Changes to Objective-C:
375
 
376
    Bare-bones implementation of NXConstantString has been added,
377
    which is invoked by the @"string" directive.
378
 
379
    Class * has been changed to Class to conform to the NextSTEP and
380
    OpenStep runtime.
381
 
382
    Enhancements to make dynamic loading easier.
383
 
384
    The module version number has been updated to Version 7, thus existing
385
    code will need to be recompiled to use the current run-time library.
386
 
387
GCC now supports the ISO Normative Addendum 1 to the C Standard.
388
As a result:
389
 
390
    The header  defines macros for C programs written
391
    in national variants of ISO 646.
392
 
393
    The following digraph tokens are supported:
394
        <:	:>        <%	%>        %:      %:%:
395
    These behave like the following, respectively:
396
        [       ]       {       }       #       ##
397
 
398
    Digraph tokens are supported unless you specify the `-traditional'
399
    option; you do not need to specify `-ansi' or `-trigraphs'.  Except
400
    for contrived and unlikely examples involving preprocessor
401
    stringizing, digraph interpretation doesn't change the meaning of
402
    programs; this is unlike trigraph interpretation, which changes the
403
    meanings of relatively common strings.
404
 
405
    The macro __STDC_VERSION__ has the value 199409L.
406
 
407
  As usual, for full conformance to the standard, you also need a
408
  C library that conforms.
409
 
410
The following lists changes that have been made to g++.  If some
411
features mentioned below sound unfamiliar, you will probably want to
412
look at the recently-released public review copy of the C++ Working
413
Paper.  For PostScript and PDF (Adobe Acrobat) versions, see the
414
archive at ftp://research.att.com/dist/stdc++/WP.  For HTML and ASCII
415
versions, see ftp://ftp.cygnus.com/pub/g++.  On the web, see
416
http://www.cygnus.com/~mrs/wp-draft.
417
 
418
The scope of variables declared in the for-init-statement has been changed
419
to conform to http://www.cygnus.com/~mrs/wp-draft/stmt.html#stmt.for; as a
420
result, packages such as groff 1.09 will not compile unless you specify the
421
-fno-for-scope flag.  PLEASE DO NOT REPORT THIS AS A BUG; this is a change
422
mandated by the C++ standardization committee.
423
 
424
Binary incompatibilities:
425
 
426
    The builtin 'bool' type is now the size of a machine word on RISC targets,
427
    for code efficiency; it remains one byte long on CISC targets.
428
 
429
    Code that does not use #pragma interface/implementation will most
430
    likely shrink dramatically, as g++ now only emits the vtable for a
431
    class in the translation unit where its first non-inline, non-abstract
432
    virtual function is defined.
433
 
434
    Classes that do not define the copy constructor will sometimes be
435
    passed and returned in registers.  This may illuminate latent bugs in
436
    your code.
437
 
438
Support for automatic template instantiation has *NOT* been added, due
439
to a disagreement over design philosophies.
440
 
441
Support for exception handling has been improved; more targets are now
442
supported, and throws will use the RTTI mechanism to match against the
443
catch parameter type.  Optimization is NOT SUPPORTED with
444
-fhandle-exceptions; no need to report this as a bug.
445
 
446
Support for Run-Time Type Identification has been added with -frtti.
447
This support is still in alpha; one major restriction is that any file
448
compiled with -frtti must include .
449
 
450
Preliminary support for namespaces has been added.  This support is far
451
from complete, and probably not useful.
452
 
453
Synthesis of compiler-generated constructors, destructors and
454
assignment operators is now deferred until the functions are used.
455
 
456
The parsing of expressions such as `a ? b : c = 1' has changed from
457
`(a ? b : c) = 1' to `a : b ? (c = 1)'.
458
 
459
The code generated for testing conditions, especially those using ||
460
and &&, is now more efficient.
461
 
462
The operator keywords and, and_eq, bitand, bitor, compl, not, not_eq,
463
or, or_eq, xor and xor_eq are now supported.  Use -ansi or
464
-foperator-names to enable them.
465
 
466
The 'explicit' keyword is now supported.  'explicit' is used to mark
467
constructors and type conversion operators that should not be used
468
implicitly.
469
 
470
g++ now accepts the typename keyword, though it currently has no
471
semantics; it can be a no-op in the current template implementation.
472
You may want to start using it in your code, however, since the
473
pending rewrite of the template implementation to compile STL properly
474
(perhaps for 2.8.0, perhaps not) will require you to use it as
475
indicated by the current draft.
476
 
477
Handling of user-defined type conversion has been overhauled so that
478
type conversion operators are now found and used properly in
479
expressions and function calls.
480
 
481
-fno-strict-prototype now only applies to function declarations with
482
"C" linkage.
483
 
484
g++ now warns about 'if (x=0)' with -Wparentheses or -Wall.
485
 
486
#pragma weak and #pragma pack are supported on System V R4 targets, as
487
are various other target-specific #pragmas supported by gcc.
488
 
489
new and delete of const types is now allowed (with no additional
490
semantics).
491
 
492
Explicit instantiation of template methods is now supported.  Also,
493
'inline template class foo;' can be used to emit only the vtable
494
for a template class.
495
 
496
With -fcheck-new, g++ will check the return value of all calls to
497
operator new, and not attempt to modify a returned null pointer.
498
 
499
The template instantiation code now handles more conversions when
500
passing to a parameter that does not depend on template arguments.
501
This means that code like 'string s; cout << s;' now works.
502
 
503
Invalid jumps in a switch statement past declarations that require
504
initializations are now caught.
505
 
506
Functions declared 'extern inline' now have the same linkage semantics
507
as inline member functions.  On supported targets, where previously
508
these functions (and vtables, and template instantiations) would have
509
been defined statically, they will now be defined as weak symbols so
510
that only one out-of-line definition is used.
511
 
512
collect2 now demangles linker output, and c++filt has become part of
513
the gcc distribution.
514
 
515
Noteworthy changes in GCC version 2.6.3:
516
 
517
A few more bugs have been fixed.
518
 
519
Noteworthy changes in GCC version 2.6.2:
520
 
521
A few bugs have been fixed.
522
 
523
Names of attributes can now be preceded and followed by double underscores.
524
 
525
Noteworthy changes in GCC version 2.6.1:
526
 
527
Numerous (mostly minor) bugs have been fixed.
528
 
529
The following new configurations are supported:
530
 
531
        GNU on x86 (instead of treating it like MACH)
532
        NetBSD on Sparc and Motorola 68k
533
        AIX 4.1 on RS/6000 and PowerPC systems
534
        Sequent DYNIX/ptx 1.x and 2.x.
535
        Both COFF and ELF configurations on AViiON without using /bin/gcc
536
        Windows/NT on x86 architecture; preliminary
537
        AT&T DSP1610 digital signal processor chips
538
        i960 systems on bare boards using COFF
539
        PDP11; target only and not extensively tested
540
 
541
The -pg option is now supported for Alpha under OSF/1 V3.0 or later.
542
 
543
Files with an extension of ".c++" are treated as C++ code.
544
 
545
The -Xlinker and -Wl arguments are now passed to the linker in the
546
position they were specified on the command line.  This makes it
547
possible, for example, to pass flags to the linker about specific
548
object files.
549
 
550
The use of positional arguments to the configure script is no longer
551
recommended.  Use --target= to specify the target; see the GCC manual.
552
 
553
The 386 now supports two new switches: -mreg-alloc= changes
554
the default register allocation order used by the compiler, and
555
-mno-wide-multiply disables the use of the mul/imul instructions that
556
produce 64 bit results in EAX:EDX from 32 bit operands to do long long
557
multiplies and 32-bit division by constants.
558
 
559
Noteworthy changes in GCC version 2.6.0:
560
 
561
Numerous bugs have been fixed, in the C and C++ front-ends, as
562
well as in the common compiler code.
563
 
564
This release includes the C, Objective-C, and C++ compilers.  However,
565
we have moved the files for the C++ compiler (G++) files to a
566
subdirectory, cp.  Subsequent releases of GCC will split these files
567
to a separate TAR file.
568
 
569
The G++ team has been tracking the development of the ANSI standard for C++.
570
Here are some new features added from the latest working paper:
571
 
572
        * built-in boolean type 'bool', with constants 'true' and 'false'.
573
        * array new and delete (operator new [] and delete []).
574
        * WP-conforming lifetime of temporaries.
575
        * explicit instantiation of templates (template class A;),
576
          along with an option (-fno-implicit-templates) to disable emission
577
          of implicitly instantiated templates, obsoletes -fexternal-templates.
578
        * static member constants (static const int foo = 4; within the
579
          class declaration).
580
 
581
Many error messages have been improved to tell the user more about the
582
problem.  Conformance checking with -pedantic-errors has been
583
improved.  G++ now compiles Fresco.
584
 
585
There is now an experimental implementation of virtual functions using
586
thunks instead of Cfront-style vtables, enabled with -fvtable-thunks.
587
This option also enables a heuristic which causes the compiler to only
588
emit the vtable in the translation unit where its first non-inline
589
virtual function is defined; using this option and
590
-fno-implicit-templates, users should be able to avoid #pragma
591
interface/implementation altogether.
592
 
593
Signatures have been added as a GNU C++ extension.  Using the option
594
-fhandle-signatures, users are able to turn on recognition of
595
signatures.  A short introduction on signatures is in the section
596
`Extension to the C++ Language' in the manual.
597
 
598
The `g++' program is now a C program, rather than a shell script.
599
 
600
Lots and lots and lots of bugs fixes, in nested types, access control,
601
pointers to member functions, the parser, templates, overload
602
resolution, etc, etc.
603
 
604
There have been two major enhancements to the Objective-C compiler:
605
 
606
1) Added portability.  It now runs on Alpha, and some problems with
607
   message forwarding have been addressed on other platforms.
608
 
609
2) Selectors have been redefined to be pointers to structs like:
610
   { void *sel_id, char *sel_types }, where the sel_id is the unique
611
   identifier, the selector itself is no longer unique.
612
 
613
   Programmers should use the new function sel_eq to test selector
614
   equivalence.
615
 
616
The following major changes have been made to the base compiler and
617
machine-specific files.
618
 
619
- The MIL-STD-1750A is a new port, but still preliminary.
620
 
621
- The h8/300h is now supported; both the h8/300 and h8/300h ports come
622
  with 32 bit IEEE 754 software floating point support.
623
 
624
- The 64-bit Sparc (v9) and 64-bit MIPS chips are supported.
625
 
626
- NetBSD is supported on m68k, Intel x86, and pc523 systems and FreeBSD
627
  on x86.
628
 
629
- COFF is supported on x86, m68k, and Sparc systems running LynxOS.
630
 
631
- 68K systems from Bull and Concurrent are supported and System V
632
  Release 4 is supported on the Atari.
633
 
634
- GCC supports GAS on the Motorola 3300 (sysV68) and debugging
635
  (assuming GAS) on the Plexus 68K system.  (However, GAS does not yet
636
  work on those systems).
637
 
638
- System V Release 4 is supported on MIPS (Tandem).
639
 
640
- For DG/UX, an ELF configuration is now supported, and both the ELF
641
  and BCS configurations support ELF and COFF object file formats.
642
 
643
- OSF/1 V2.0 is supported on Alpha.
644
 
645
- Function profiling is also supported on Alpha.
646
 
647
- GAS and GDB is supported for Irix 5 (MIPS).
648
 
649
- "common mode" (code that will run on both POWER and PowerPC
650
  architectures) is now supported for the RS/6000 family; the
651
  compiler knows about more PPC chips.
652
 
653
- Both NeXTStep 2.1 and 3 are supported on 68k-based architectures.
654
 
655
- On the AMD 29k, the -msoft-float is now supported, as well as
656
  -mno-sum-in-toc for RS/6000, -mapp-regs and -mflat for Sparc, and
657
  -membedded-pic for MIPS.
658
 
659
- GCC can now convert division by integer constants into the equivalent
660
  multiplication and shift operations when that is faster than the
661
  division.
662
 
663
- Two new warning options, -Wbad-function-cast and
664
  -Wmissing-declarations have been added.
665
 
666
- Configurations may now add machine-specific __attribute__ options on
667
  type; many machines support the `section' attribute.
668
 
669
- The -ffast-math flag permits some optimization that violate strict
670
  IEEE rules, such as converting X * 0.0 to 0.0.
671
 
672
Noteworthy changes in GCC version 2.5.8:
673
 
674
This release only fixes a few serious bugs.  These include fixes for a
675
bug that prevented most programs from working on the RS/6000, a bug
676
that caused invalid assembler code for programs with a `switch'
677
statement on the NS32K, a G++ problem that caused undefined names in
678
some configurations, and several less serious problems, some of which
679
can affect most configuration.
680
 
681
Noteworthy change in GCC version 2.5.7:
682
 
683
This release only fixes a few bugs, one of which was causing bootstrap
684
compare errors on some systems.
685
 
686
Noteworthy change in GCC version 2.5.6:
687
 
688
A few backend bugs have been fixed, some of which only occur on one
689
machine.
690
 
691
The C++ compiler in 2.5.6 includes:
692
 
693
 * fixes for some common crashes
694
 * correct handling of nested types that are referenced as `foo::bar'
695
 * spurious warnings about friends being declared static and never
696
   defined should no longer appear
697
 * enums that are local to a method in a class, or a class that's
698
   local to a function, are now handled correctly.  For example:
699
       class foo { void bar () { enum { x, y } E; x; } };
700
       void bar () { class foo { enum { x, y } E; E baz; }; }
701
 
702
Noteworthy change in GCC version 2.5.5:
703
 
704
A large number of C++ bugs have been fixed.
705
 
706
The fixproto script adds prototypes conditionally on __cplusplus.
707
 
708
Noteworthy change in GCC version 2.5.4:
709
 
710
A bug fix in passing of structure arguments for the HP-PA architecture
711
makes code compiled with GCC 2.5.4 incompatible with code compiled
712
with earlier versions (if it passes struct arguments of 33 to 64 bits,
713
interspersed with other types of arguments).
714
 
715
Noteworthy change in gcc version 2.5.3:
716
 
717
The method of "mangling" C++ function names has been changed.  So you
718
must recompile all C++ programs completely when you start using GCC
719
2.5.  Also, GCC 2.5 requires libg++ version 2.5.  Earlier libg++
720
versions won't work with GCC 2.5.  (This is generally true--GCC
721
version M.N requires libg++ version M.N.)
722
 
723
Noteworthy GCC changes in version 2.5:
724
 
725
* There is now support for the IBM 370 architecture as a target.
726
Currently the only operating system supported is MVS; GCC does not run
727
on MVS, so you must produce .s files using GCC as a cross compiler,
728
then transfer them to MVS to assemble them.  This port is not reliable
729
yet.
730
 
731
* The Power PC is now supported.
732
 
733
* The i860-based Paragon machine is now supported.
734
 
735
* The Hitachi 3050 (an HP-PA machine) is now supported.
736
 
737
* The variable __GNUC_MINOR__ holds the minor version number of GCC, as
738
an integer.  For version 2.5.X, the value is 5.
739
 
740
* In C, initializers for static and global variables are now processed
741
an element at a time, so that they don't need a lot of storage.
742
 
743
* The C syntax for specifying which structure field comes next in an
744
initializer is now `.FIELDNAME='.  The corresponding syntax for
745
array initializers is now `[INDEX]='.  For example,
746
 
747
  char whitespace[256]
748
    = { [' '] = 1, ['\t'] = 1, ['\n'] = 1 };
749
 
750
This was changed to accord with the syntax proposed by the Numerical
751
C Extensions Group (NCEG).
752
 
753
* Complex numbers are now supported in C.  Use the keyword __complex__
754
to declare complex data types.  See the manual for details.
755
 
756
* GCC now supports `long double' meaningfully on the Sparc (128-bit
757
floating point) and on the 386 (96-bit floating point).  The Sparc
758
support is enabled on Solaris 2.x because earlier system versions
759
(SunOS 4) have bugs in the emulation.
760
 
761
* All targets now have assertions for cpu, machine and system.  So you
762
can now use assertions to distinguish among all supported targets.
763
 
764
* Nested functions in C may now be inline.  Just declare them inline
765
in the usual way.
766
 
767
* Packed structure members are now supported fully; it should be possible
768
to access them on any supported target, no matter how little alignment
769
they have.
770
 
771
* To declare that a function does not return, you must now write
772
something like this (works only in 2.5):
773
 
774
    void fatal () __attribute__ ((noreturn));
775
 
776
or like this (works in older versions too):
777
 
778
    typedef void voidfn ();
779
 
780
    volatile voidfn fatal;
781
 
782
It used to be possible to do so by writing this:
783
 
784
    volatile void fatal ();
785
 
786
but it turns out that ANSI C requires that to mean something
787
else (which is useless).
788
 
789
Likewise, to declare that a function is side-effect-free
790
so that calls may be deleted or combined, write
791
something like this (works only in 2.5):
792
 
793
    int computation () __attribute__ ((const));
794
 
795
or like this (works in older versions too):
796
 
797
    typedef int intfn ();
798
 
799
    const intfn computation;
800
 
801
* The new option -iwithprefixbefore specifies a directory to add to
802
the search path for include files in the same position where -I would
803
put it, but uses the specified prefix just like -iwithprefix.
804
 
805
* Basic block profiling has been enhanced to record the function the
806
basic block comes from, and if the module was compiled for debugging,
807
the line number and filename.  A default version of the basic block
808
support module has been added to libgcc2 that appends the basic block
809
information to a text file 'bb.out'.  Machine descriptions can now
810
override the basic block support module in the target macro file.
811
 
812
New features in g++:
813
 
814
* The new flag `-fansi-overloading' for C++.  Use a newly implemented
815
scheme of argument matching for C++.  It makes g++ more accurately
816
obey the rules set down in Chapter 13 of the Annotated C++ Reference
817
Manual (the ARM).  This option will be turned on by default in a
818
future release.
819
 
820
* The -finline-debug flag is now gone (it was never really used by the
821
  compiler).
822
 
823
* Recognizing the syntax for pointers to members, e.g., "foo::*bar", has been
824
  dramatically improved.  You should not get any syntax errors or incorrect
825
  runtime results while using pointers to members correctly; if you do, it's
826
  a definite bug.
827
 
828
* Forward declaration of an enum is now flagged as an error.
829
 
830
* Class-local typedefs are now working properly.
831
 
832
* Nested class support has been significantly improved.  The compiler
833
  will now (in theory) support up to 240 nested classes before hitting
834
  other system limits (like memory size).
835
 
836
* There is a new C version of the `g++' driver, to replace the old
837
  shell script.  This should significantly improve the performance of
838
  executing g++ on a system where a user's PATH environment variable
839
  references many NFS-mounted filesystems.  This driver also works
840
  under MS-DOS and OS/2.
841
 
842
* The ANSI committee working on the C++ standard has adopted a new
843
  keyword `mutable'.  This will allow you to make a specific member be
844
  modifiable in an otherwise const class.
845
 
846
Noteworthy GCC changes in version 2.4.4:
847
 
848
  A crash building g++ on various hosts (including m68k) has been
849
  fixed.  Also the g++ compiler no longer reports incorrect
850
  ambiguities in some situations where they do not exist, and
851
  const template member functions are now being found properly.
852
 
853
Noteworthy GCC changes in version 2.4:
854
 
855
* On each target, the default is now to return short structures
856
compatibly with the "usual" compiler on that target.
857
 
858
For most targets, this means the default is to return all structures
859
in memory, like long structures, in whatever way is used on that
860
target.  Use -freg-struct-return to enable returning short structures
861
(and unions) in registers.
862
 
863
This change means that newly compiled binaries are incompatible with
864
binaries compiled with previous versions of GCC.
865
 
866
On some targets, GCC is itself the usual compiler.  On these targets,
867
the default way to return short structures is still in registers.
868
Use -fpcc-struct-return to tell GCC to return them in memory.
869
 
870
* There is now a floating point emulator which can imitate the way all
871
supported target machines do floating point arithmetic.
872
 
873
This makes it possible to have cross compilation to and from the VAX,
874
and between machines of different endianness.  However, this works
875
only when the target machine description is updated to use the new
876
facilities, and not all have been updated.
877
 
878
This also makes possible support for longer floating point types.
879
GCC 2.4 supports extended format on the 68K if you use `long double',
880
for targets that have a 68881.  (When we have run time library
881
routines for extended floating point, then `long double' will use
882
extended format on all 68K targets.)
883
 
884
We expect to support extended floating point on the i386 and Sparc in
885
future versions.
886
 
887
* Building GCC now automatically fixes the system's header files.
888
This should require no attention.
889
 
890
* GCC now installs an unsigned data type as size_t when it fixes the
891
header files (on all but a handful of old target machines).
892
Therefore, the bug that size_t failed to be unsigned is fixed.
893
 
894
* Building and installation are now completely separate.
895
All new files are constructed during the build process;
896
installation just copies them.
897
 
898
* New targets supported: Clipper, Hitachi SH, Hitachi 8300, and Sparc
899
Lite.
900
 
901
* A totally new and much better Objective C run time system is included.
902
 
903
* Objective C supports many new features.  Alas, I can't describe them
904
since I don't use that language; however, they are the same ones
905
supported in recent versions of the NeXT operating system.
906
 
907
* The builtin functions __builtin_apply_args, __builtin_apply and
908
__builtin_return let you record the arguments and returned
909
value of a function without knowing their number or type.
910
 
911
* The builtin string variables __FUNCTION__ and __PRETTY_FUNCTION__
912
give the name of the function in the source, and a pretty-printed
913
version of the name.  The two are the same in C, but differ in C++.
914
 
915
* Casts to union types do not yield lvalues.
916
 
917
* ## before an empty rest argument discards the preceding sequence
918
of non-whitespace characters from the macro definition.
919
(This feature is subject to change.)
920
 
921
 
922
New features specific to C++:
923
 
924
* The manual contains a new section ``Common Misunderstandings with
925
GNU C++'' that C++ users should read.
926
 
927
* #pragma interface and #pragma implementation let you use the same
928
C++ source file for both interface and implementation.
929
However, this mechanism is still in transition.
930
 
931
* Named returned values let you avoid an extra constructor call
932
when a function result has a class type.
933
 
934
* The C++ operators ? yield min and max, respectively.
935
 
936
* C++ gotos can exit a block safely even if the block has
937
aggregates that require destructors.
938
 
939
* gcc defines the macro __GNUG__ when compiling C++ programs.
940
 
941
* GNU C++ now correctly distinguishes between the prefix and postfix
942
forms of overloaded operator ++ and --.  To avoid breaking old
943
code, if a class defines only the prefix form, the compiler
944
accepts either ++obj or obj++, unless -pedantic is used.
945
 
946
* If you are using version 2.3 of libg++, you need to rebuild it with
947
`make CC=gcc' to avoid mismatches in the definition of `size_t'.
948
 
949
Newly documented compiler options:
950
 
951
-fnostartfiles
952
        Omit the standard system startup files when linking.
953
 
954
-fvolatile-global
955
        Consider memory references to extern and global data items to
956
        be volatile.
957
 
958
-idirafter DIR
959
        Add DIR to the second include path.
960
 
961
-iprefix PREFIX
962
        Specify PREFIX for later -iwithprefix options.
963
 
964
-iwithprefix DIR
965
        Add PREFIX/DIR to the second include path.
966
 
967
-mv8
968
        Emit Sparc v8 code (with integer multiply and divide).
969
-msparclite
970
        Emit Sparclite code (roughly v7.5).
971
 
972
-print-libgcc-file-name
973
        Search for the libgcc.a file, print its absolute file name, and exit.
974
 
975
-Woverloaded-virtual
976
        Warn when a derived class function declaration may be an error
977
        in defining a C++ virtual function.
978
 
979
-Wtemplate-debugging
980
        When using templates in a C++ program, warn if debugging is
981
        not yet fully available.
982
 
983
+eN
984
        Control how C++ virtual function definitions are used
985
        (like cfront 1.x).
986
 
987
 
988
Copyright (C) 2000, 2001, 2003 Free Software Foundation, Inc.
989
 
990
Copying and distribution of this file, with or without modification,
991
are permitted in any medium without royalty provided the copyright
992
notice and this notice are preserved.

powered by: WebSVN 2.1.0

© copyright 1999-2024 OpenCores.org, equivalent to Oliscience, all rights reserved. OpenCores®, registered trademark.