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Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	1	<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
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Reid Spencer	e4190fa	2004-11-18 18:38:58 +0000	[diff] [blame]	5	<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	6	<link rel="stylesheet" href="llvm.css" type="text/css">
Chris Lattner	f3a7c24	2004-12-09 22:22:58 +0000	[diff] [blame]	7	<title>LLVM 1.5 Release Notes</title>
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	8	</head>
				9	<body>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	10
Chris Lattner	f3a7c24	2004-12-09 22:22:58 +0000	[diff] [blame]	11	<div class="doc_title">LLVM 1.5 Release Notes</div>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	12
				13	<ol>
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	14	<li><a href="#intro">Introduction</a></li>
				15	<li><a href="#whatsnew">What's New?</a></li>
Chris Lattner	77a5173	2004-04-30 22:17:12 +0000	[diff] [blame]	16	<li><a href="GettingStarted.html">Installation Instructions</a></li>
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	17	<li><a href="#portability">Portability and Supported Platforms</a></li>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	18	<li><a href="#knownproblems">Known Problems</a>
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	19	<li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	20	</ol>
				21
Chris Lattner	020e1fc	2004-05-23 21:07:27 +0000	[diff] [blame]	22	<div class="doc_author">
Chris Lattner	f3a7c24	2004-12-09 22:22:58 +0000	[diff] [blame]	23	<p>Written by the <a href="http://llvm.cs.uiuc.edu">LLVM Team</a><p>
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	24	</div>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	25
				26	<!-- *********************************************************************** -->
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	27	<div class="doc_section">
				28	<a name="intro">Introduction</a>
				29	</div>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	30	<!-- *********************************************************************** -->
				31
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	32	<div class="doc_text">
				33
				34	<p>This document contains the release notes for the LLVM compiler
Chris Lattner	f3a7c24	2004-12-09 22:22:58 +0000	[diff] [blame]	35	infrastructure, release 1.5. Here we describe the status of LLVM, including any
Chris Lattner	406bddf	2005-05-15 05:44:51 +0000	[diff] [blame]	36	known problems and major improvements from the previous release. The most
				37	up-to-date version of this document can be found on the <a
Chris Lattner	f3a7c24	2004-12-09 22:22:58 +0000	[diff] [blame]	38	href="http://llvm.cs.uiuc.edu/releases/1.5/">LLVM 1.5 web site</a>. If you are
John Criswell	86a3a48	2003-12-18 16:43:17 +0000	[diff] [blame]	39	not reading this on the LLVM web pages, you should probably go there because
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	40	this document may be updated after the release.</p>
Chris Lattner	6249576	2003-10-02 16:38:05 +0000	[diff] [blame]	41
Chris Lattner	b5bb597	2004-12-07 08:04:13 +0000	[diff] [blame]	42	<p>For more information about LLVM, including information about the latest
				43	release, please check out the <a href="http://llvm.cs.uiuc.edu">main LLVM
Chris Lattner	e7525b5	2003-10-07 21:38:31 +0000	[diff] [blame]	44	web site</a>. If you have questions or comments, the <a
				45	href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	46	list</a> is a good place to send them.</p>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	47
Chris Lattner	f3a7c24	2004-12-09 22:22:58 +0000	[diff] [blame]	48	<p>Note that if you are reading this file from CVS or the main LLVM web page,
				49	this document applies to the <i>next</i> release, not the current one. To see
				50	the release notes for the current or previous releases, see the <a
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	51	href="http://llvm.cs.uiuc.edu/releases/">releases page</a>.</p>
				52
				53	</div>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	54
				55	<!-- *********************************************************************** -->
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	56	<div class="doc_section">
				57	<a name="whatsnew">What's New?</a>
				58	</div>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	59	<!-- *********************************************************************** -->
				60
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	61	<div class="doc_text">
				62
Chris Lattner	406bddf	2005-05-15 05:44:51 +0000	[diff] [blame]	63	<p>This is the sixth public release of the LLVM Compiler Infrastructure.</p>
Chris Lattner	ba7bd47	2003-12-06 20:22:41 +0000	[diff] [blame]	64
Chris Lattner	406bddf	2005-05-15 05:44:51 +0000	[diff] [blame]	65	<p> At this time, LLVM is known to correctly compile a wide range of C and C++
				66	programs, including the SPEC CPU95 & 2000 suite. It includes bug fixes for
				67	those problems found since the 1.4 release and a large number of new features
				68	and enhancements, described below.</p>
Chris Lattner	ba7bd47	2003-12-06 20:22:41 +0000	[diff] [blame]	69
Chris Lattner	21a9040	2004-05-24 04:50:25 +0000	[diff] [blame]	70	</div>
				71
Chris Lattner	ba7bd47	2003-12-06 20:22:41 +0000	[diff] [blame]	72	<!--=========================================================================-->
Chris Lattner	406bddf	2005-05-15 05:44:51 +0000	[diff] [blame]	73	<div class="doc_subsection">
				74	<a name="newfeatures">New Features in LLVM 1.5</a>
Chris Lattner	ba7bd47	2003-12-06 20:22:41 +0000	[diff] [blame]	75	</div>
Chris Lattner	e7525b5	2003-10-07 21:38:31 +0000	[diff] [blame]	76
Chris Lattner	406bddf	2005-05-15 05:44:51 +0000	[diff] [blame]	77	<!--_________________________________________________________________________-->
				78	<div class="doc_subsubsection">New Native Code Generators</div>
				79
				80	<div class="doc_text">
				81	<p>
				82	This release includes new native code generators for <a
				83	href="#alpha-be">Alpha</a>, <a href="#ia64-be">IA-64</a>, and SPARC-V8 (32-bit
				84	SPARC). These code generators are still beta quality, but are progressing
				85	rapidly.
				86	</p>
				87	</div>
				88
				89	<!--_________________________________________________________________________-->
				90	<div class="doc_subsubsection">New Instruction Selector Framework</div>
				91
				92	<div class="doc_text">
				93	<p>This release includes a <a href="CodeGenerator.html#instselect">new framework
				94	for building instruction selectors</a>, which has long been the hardest part of
				95	building a new LLVM target. This framework handles a lot of the mundane (but
				96	easy to get wrong) details of writing the instruction selector, such as
				97	generating efficient code for <a
				98	href="LangRef.html#i_getelementptr">getelementptr</a> instructions, promoting
				99	small integer types to larger types (e.g. for RISC targets with one size of
				100	integer registers), expanding 64-bit integer operations for 32-bit hosts, etc.
				101	Currently, the X86, PowerPC, Alpha, and IA-64 backends use this framework. The
				102	SPARC backends will be migrated when time permits.
				103	</p>
				104	</div>
				105
				106	<!--_________________________________________________________________________-->
				107	<div class="doc_subsubsection">New Support For Custom Calling Convetions</div>
				108
				109	<div class="doc_text">
				110	<p>LLVM 1.5 adds supports for <a href="LangRef.html#callingconv">custom and
				111	target-specific calling conventions</a>. Traditionally, the LLVM code
				112	generators match the native C calling conventions for a target. This is
				113	important for compatibility, but is not very flexible. This release allows
				114	custom calling conventions to be established for functions, and defines three
				115	target-independent conventions (C call, fast call, and cold call) which may be
				116	supported by code generators. When possible, the LLVM optimizer promotes C
				117	functions to use the "fastcc" convention, allowing the use of more efficient
				118	calling sequences (e.g., parameters are passed in registers in the X86 target).
				119	</p>
				120
				121	<p>Targets may now also define target-specific calling conventions, allowing
				122	LLVM to fully support calling convention altering options (e.g. GCC's
				123	<tt>-mregparm</tt> flag) and well-defined target conventions (e.g. stdcall and
				124	fastcall on X86).</p>
				125	</div>
				126
				127	<!--_________________________________________________________________________-->
				128	<div class="doc_subsubsection">New Support for "Proper Tail Calls"</div>
				129
				130	<div class="doc_text">
				131	<p>The release now includes support for <a
				132	href="http://doi.acm.org/10.1145/277650.277719">proper tail calls</a>, as
				133	required to implement languages like Scheme. Tail calls make use of two
				134	features: custom calling conventions (described above), which allow the code
				135	generator to emit code for the caller to deallocate its own stack when it
				136	returns. The second feature is a flag on the <a href="LangRef.html#i_call">call
				137	instruction</a>, which indicates that the callee does not access the callers
				138	stack frame (indicating that it is acceptable to deallocate the caller stack
				139	before invoking the callee). LLVM proper tail calls run on the system stack (as
				140	do normal calls), supports indirect tail calls, tail calls with arbitrary
				141	numbers of arguments, tail calls where the callee requires more argument space
				142	than the caller, etc. The only case not supported are varargs calls, but that
				143	could be added if desired.
				144	</p>
				145
				146	<p>In order for a front-end to get guaranteed tail call, it must mark functions
				147	as "fastcc", mark calls with the 'tail' marker, and follow the call with a
				148	return of the called value (or void). The optimizer and code generator attempt
				149	to handle more general cases, but the simple case will always work if the code
				150	generator supports tail calls. Here is a simple example:</p>
				151
				152	<p><pre>
Chris Lattner	55f987b	2005-05-15 06:07:40 +0000	[diff] [blame^]	153	fastcc int %bar(int %X, int(double, int)* %FP) { ;<i> fastcc</i>
				154	%Y = tail call fastcc int %FP(double 0.0, int %X) ;<i> tail, fastcc</i>
				155	ret int %Y
				156	}
Chris Lattner	406bddf	2005-05-15 05:44:51 +0000	[diff] [blame]	157	</pre></p>
				158
				159	<p>In LLVM 1.5, the X86 code generator is the only target that has been enhanced
				160	to support proper tail calls (other targets will be enhanced in future).
				161	Further, because this support was added very close to the release, it is
Chris Lattner	55f987b	2005-05-15 06:07:40 +0000	[diff] [blame^]	162	disabled by default. Pass <tt>-enable-x86-fastcc</tt> to llc to enable it (this
				163	will be enabled by default in the next release). The example above compiles to:
				164	</p>
				165
				166	<p><pre>
				167	bar:
				168	sub ESP, 8 # Callee uses more space than the caller
				169	mov ECX, DWORD PTR [ESP + 8] # Get the old return address
				170	mov DWORD PTR [ESP + 4], 0 # First half of 0.0
				171	mov DWORD PTR [ESP + 8], 0 # Second half of 0.0
				172	mov DWORD PTR [ESP], ECX # Put the return address where it belongs
				173	jmp EDX # Tail call "FP"
				174	</pre></p>
				175
				176	<p>
				177	With fastcc on X86, the first two integer arguments are passed in EAX/EDX, the
				178	callee pops its arguments off the stack, and the argument area is always a
				179	multiple of 8 bytes in size.
				180	</p>
				181
Chris Lattner	406bddf	2005-05-15 05:44:51 +0000	[diff] [blame]	182	</div>
				183
				184	<!--_________________________________________________________________________-->
				185	<div class="doc_subsubsection">Other New Features</div>
				186
Chris Lattner	21a9040	2004-05-24 04:50:25 +0000	[diff] [blame]	187	<div class="doc_text">
Chris Lattner	e7525b5	2003-10-07 21:38:31 +0000	[diff] [blame]	188	<ol>
Chris Lattner	7bf2e54	2004-12-11 06:10:52 +0000	[diff] [blame]	189	<li>LLVM now includes an <a href="http://llvm.cs.uiuc.edu/PR415">
Chris Lattner	64d9d2b	2005-01-22 18:45:35 +0000	[diff] [blame]	190	Interprocedural Sparse Conditional Constant Propagation</a> pass, named
Chris Lattner	7bf2e54	2004-12-11 06:10:52 +0000	[diff] [blame]	191	-ipsccp, which is run by default at link-time.</li>
Chris Lattner	406bddf	2005-05-15 05:44:51 +0000	[diff] [blame]	192	<li>LLVM 1.5 is now about 15% faster than LLVM 1.4 and its core data
				193	structures use about 30% less memory.</li>
Chris Lattner	e14babd	2005-02-13 22:27:24 +0000	[diff] [blame]	194	<li>Support for Microsoft Visual Studio is improved, and <a
Chris Lattner	be895ed	2005-02-14 22:58:38 +0000	[diff] [blame]	195	href="GettingStartedVS.html">now documented</a>.</li>
Chris Lattner	406bddf	2005-05-15 05:44:51 +0000	[diff] [blame]	196	<li><a href="GettingStarted.html#config">Configuring LLVM to build a subset
				197	of the available targets</a> is now implemented, via the
				198	<tt>--enable-targets=</tt> option.</li>
Chris Lattner	81c1dd2	2005-02-28 16:52:28 +0000	[diff] [blame]	199	<li>LLVM can now create native shared libraries with '<tt>llvm-gcc ...
				200	-shared -Wl,-native</tt>' (or with <tt>-Wl,-native-cbe</tt>).</li>
Chris Lattner	db302f8	2005-03-11 06:16:26 +0000	[diff] [blame]	201	<li>LLVM now supports a new "<a href="LangRef.html#i_prefetch">llvm.prefetch
				202	</a>" intrinsic, and llvm-gcc now supports __builtin_prefetch.
Chris Lattner	b34b273	2005-05-07 02:21:21 +0000	[diff] [blame]	203	<li>LLVM now supports intrinsics for <a href="LangRef.html#int_count">bit
				204	counting</a> and llvm-gcc now implements the GCC
				205	<tt>__builtin_popcount</tt>, <tt>__builtin_ctz</tt>, and
				206	<tt>__builtin_clz</tt> builtins.</li>
Chris Lattner	406bddf	2005-05-15 05:44:51 +0000	[diff] [blame]	207	<li>LLVM now builds on HP-UX with the HP aCC Compiler.</li>
				208	<li>The LLVM X86 backend can now emit Cygwin-compatible .s files.</li>
				209	<li>LLVM now includes workarounds in the code generator generator which
				210	reduces the likelyhood of <a href="http://llvm.cs.uiuc.edu/PR448">GCC
				211	hitting swap during optimized builds</a>.</li>
Brian Gaeke	8b05e4f	2004-01-16 21:55:04 +0000	[diff] [blame]	212	</ol>
Chris Lattner	21a9040	2004-05-24 04:50:25 +0000	[diff] [blame]	213	</div>
Brian Gaeke	8b05e4f	2004-01-16 21:55:04 +0000	[diff] [blame]	214
				215	<!--=========================================================================-->
Chris Lattner	406bddf	2005-05-15 05:44:51 +0000	[diff] [blame]	216	<div class="doc_subsection">
				217	<a name="codequality">Code Quality Improvements in LLVM 1.5</a>
Chris Lattner	2325706	2004-05-23 20:42:08 +0000	[diff] [blame]	218	</div>
Chris Lattner	639579c	2003-10-27 17:06:39 +0000	[diff] [blame]	219
Chris Lattner	21a9040	2004-05-24 04:50:25 +0000	[diff] [blame]	220	<div class="doc_text">
Chris Lattner	639579c	2003-10-27 17:06:39 +0000	[diff] [blame]	221	<ol>
Chris Lattner	406bddf	2005-05-15 05:44:51 +0000	[diff] [blame]	222	<li>The -globalopt pass now promotes non-address-taken static globals that are
				223	only accessed in main to SSA registers.</li>
				224
				225	<li>Loops with trip counts based on array pointer comparisons (e.g. "<tt>for (i
				226	= 0; &A[i] != &A[100]; ++i) ...</tt>") are optimized better than before,
				227	which primarily helps iterator-intensive C++ codes.</li>
				228
				229	<li>The code generator now uses information about takes advantage of commutative
				230	two-address instructions when performing register allocation.</li>
				231
Reid Spencer	ea77685	2005-05-15 06:05:11 +0000	[diff] [blame]	232	<li>A new pass has been added to gccas to simplify well-known library calls. The
				233	pass will short circuit calls to many of the string, memory, and printf type
				234	functions or replace the calls with simpler/faster calls, where possible given
				235	information known statically about the arguments to the call. To use the
				236	pass, specify <tt>-simplify-libcalls</tt> to the <tt>opt</tt> tool.</li>
				237
Chris Lattner	406bddf	2005-05-15 05:44:51 +0000	[diff] [blame]	238
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	239	</ol>
Reid Spencer	3e58f58	2004-05-23 17:23:13 +0000	[diff] [blame]	240	</div>
Chris Lattner	ba7bd47	2003-12-06 20:22:41 +0000	[diff] [blame]	241
				242	<!--=========================================================================-->
Chris Lattner	406bddf	2005-05-15 05:44:51 +0000	[diff] [blame]	243	<div class="doc_subsection">
				244	<a name="bugfix">Significant Bugs Fixed in LLVM 1.5</a>
Chris Lattner	ba7bd47	2003-12-06 20:22:41 +0000	[diff] [blame]	245	</div>
				246
Chris Lattner	21a9040	2004-05-24 04:50:25 +0000	[diff] [blame]	247	<div class="doc_text">
				248
Chris Lattner	e7525b5	2003-10-07 21:38:31 +0000	[diff] [blame]	249
Chris Lattner	1c75b25	2005-02-14 16:57:55 +0000	[diff] [blame]	250	<p>Bugs fixed in the LLVM Core:</p>
Chris Lattner	e7525b5	2003-10-07 21:38:31 +0000	[diff] [blame]	251	<ol>
Chris Lattner	b5c253a	2004-12-29 04:39:50 +0000	[diff] [blame]	252	<li><a href="http://llvm.cs.uiuc.edu/PR491">[dse] DSE deletes stores that
				253	are partially overwritten by smaller stores</a></li>
Chris Lattner	181c818	2005-04-19 06:08:04 +0000	[diff] [blame]	254	<li><a href="http://llvm.cs.uiuc.edu/PR548">[instcombine] miscompilation of
				255	setcc or setcc in one case</a></li>
Chris Lattner	406bddf	2005-05-15 05:44:51 +0000	[diff] [blame]	256	<li>Transition code for LLVM 1.0 style varargs was removed from the .ll file
				257	parser. LLVM 1.0 bytecode files are still supported. </li>
Chris Lattner	ba7bd47	2003-12-06 20:22:41 +0000	[diff] [blame]	258	</ol>
				259
Chris Lattner	1c75b25	2005-02-14 16:57:55 +0000	[diff] [blame]	260	<p>Code Generator Bugs:</p>
				261	<ol>
				262	<li><a href="http://llvm.cs.uiuc.edu/PR490">[cbackend] Logical constant
				263	expressions (and/or/xor) not implemented</a></li>
				264	<li><a href="http://llvm.cs.uiuc.edu/PR511">[cbackend] C backend does not
				265	respect 'volatile'</a></li>
				266	</ol>
Chris Lattner	ba7bd47	2003-12-06 20:22:41 +0000	[diff] [blame]	267
Chris Lattner	1c75b25	2005-02-14 16:57:55 +0000	[diff] [blame]	268	<p>Bugs in the C/C++ front-end:</p>
Chris Lattner	ba7bd47	2003-12-06 20:22:41 +0000	[diff] [blame]	269	<ol>
Chris Lattner	e1329f4	2005-01-03 04:20:21 +0000	[diff] [blame]	270	<li><a href="http://llvm.cs.uiuc.edu/PR487">[llvmgcc] llvm-gcc incorrectly
				271	rejects some constant initializers involving the addresses of array
				272	elements</a></li>
Chris Lattner	2a38aea	2005-02-11 19:29:52 +0000	[diff] [blame]	273	<li><a href="http://llvm.cs.uiuc.edu/PR501">[llvm-g++] Crash compiling
				274	anonymous union</a></li>
Chris Lattner	1c75b25	2005-02-14 16:57:55 +0000	[diff] [blame]	275	<li><a href="http://llvm.cs.uiuc.edu/PR509">[llvm-g++] Do not use dynamic
				276	initialization where static init will do</a></li>
Chris Lattner	1f031b2	2005-02-15 05:28:06 +0000	[diff] [blame]	277	<li><a href="http://llvm.cs.uiuc.edu/PR510">[llvmgcc] Field offset
				278	miscalculated for some structure fields following bit fields</a></li>
Chris Lattner	385a473	2005-02-15 07:02:12 +0000	[diff] [blame]	279	<li><a href="http://llvm.cs.uiuc.edu/PR513">[llvm-g++] Temporary lifetimes
				280	incorrect for short circuit logical operations</a></li>
Chris Lattner	48c2314	2005-02-19 07:29:25 +0000	[diff] [blame]	281	<li><a href="http://llvm.cs.uiuc.edu/PR517">[llvm-gcc] Crash compiling
				282	bitfield <-> aggregate assignment</a></li>
Chris Lattner	6a3ae64	2005-02-19 17:13:20 +0000	[diff] [blame]	283	<li><a href="http://llvm.cs.uiuc.edu/PR520">[llvm-g++] Error compiling
Chris Lattner	3d6194f	2005-02-19 17:17:32 +0000	[diff] [blame]	284	virtual function thunk with an unnamed argument</a></li>
Chris Lattner	3a8f68e	2005-02-20 23:31:49 +0000	[diff] [blame]	285	<li><a href="http://llvm.cs.uiuc.edu/PR522">[llvm-gcc] Crash on certain
				286	C99 complex number routines</a></li>
Chris Lattner	c6e3380	2005-02-27 19:31:02 +0000	[diff] [blame]	287	<li><a href="http://llvm.cs.uiuc.edu/PR529">[llvm-g++] Crash using placement
				288	new on an array type</a></li>
Brian Gaeke	730d8d6	2004-08-24 07:43:48 +0000	[diff] [blame]	289	</ol>
				290
Chris Lattner	21a9040	2004-05-24 04:50:25 +0000	[diff] [blame]	291	</div>
Reid Spencer	3e58f58	2004-05-23 17:23:13 +0000	[diff] [blame]	292
Chris Lattner	6249576	2003-10-02 16:38:05 +0000	[diff] [blame]	293	<!-- *********************************************************************** -->
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	294	<div class="doc_section">
				295	<a name="portability">Portability and Supported Platforms</a>
				296	</div>
Chris Lattner	6249576	2003-10-02 16:38:05 +0000	[diff] [blame]	297	<!-- *********************************************************************** -->
				298
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	299	<div class="doc_text">
				300
John Criswell	6430772	2004-12-08 20:35:47 +0000	[diff] [blame]	301	<p>LLVM is known to work on the following platforms:</p>
Chris Lattner	2c7b087	2004-06-01 18:22:41 +0000	[diff] [blame]	302
				303	<ul>
				304	<li>Intel and AMD machines running Red Hat Linux and FreeBSD (and probably
				305	other unix-like systems).</li>
				306	<li>Sun UltraSPARC workstations running Solaris 8.</li>
Chris Lattner	b5bb597	2004-12-07 08:04:13 +0000	[diff] [blame]	307	<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
				308	support is available for native builds with Visual C++).</li>
				309	<li>PowerPC-based Mac OS X systems, running 10.2 and above.</li>
John Criswell	d523492	2005-05-13 20:28:15 +0000	[diff] [blame]	310	<li>Alpha-based machines running Debian GNU/Linux.</li>
				311	<li>Itanium-based machines running Linux and HP-UX.</li>
Chris Lattner	2c7b087	2004-06-01 18:22:41 +0000	[diff] [blame]	312	</ul>
				313
Brian Gaeke	e3e557e	2004-05-09 05:28:35 +0000	[diff] [blame]	314	<p>The core LLVM infrastructure uses
				315	<a href="http://www.gnu.org/software/autoconf/">GNU autoconf</a> to adapt itself
				316	to the machine and operating system on which it is built. However, minor
				317	porting may be required to get LLVM to work on new platforms. We welcome your
				318	portability patches and reports of successful builds or error messages.</p>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	319
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	320	</div>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	321
				322	<!-- *********************************************************************** -->
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	323	<div class="doc_section">
				324	<a name="knownproblems">Known Problems</a>
				325	</div>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	326	<!-- *********************************************************************** -->
				327
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	328	<div class="doc_text">
				329
				330	<p>This section contains all known problems with the LLVM system, listed by
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	331	component. As new problems are discovered, they will be added to these
Chris Lattner	b84f332	2003-12-12 21:22:16 +0000	[diff] [blame]	332	sections. If you run into a problem, please check the <a
John Criswell	86a3a48	2003-12-18 16:43:17 +0000	[diff] [blame]	333	href="http://llvm.cs.uiuc.edu/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattner	b84f332	2003-12-12 21:22:16 +0000	[diff] [blame]	334	there isn't already one.</p>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	335
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	336	</div>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	337
Chris Lattner	b911de4	2004-03-14 02:03:02 +0000	[diff] [blame]	338	<!-- ======================================================================= -->
				339	<div class="doc_subsection">
				340	<a name="experimental">Experimental features included with this release</a>
				341	</div>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	342
Chris Lattner	b911de4	2004-03-14 02:03:02 +0000	[diff] [blame]	343	<div class="doc_text">
				344
Misha Brukman	fa50a22	2004-05-12 21:46:05 +0000	[diff] [blame]	345	<p>The following components of this LLVM release are either untested, known to
				346	be broken or unreliable, or are in early development. These components should
				347	not be relied on, and bugs should not be filed against them, but they may be
				348	useful to some people. In particular, if you would like to work on one of these
				349	components, please contact us on the llvmdev list.</p>
Chris Lattner	b911de4	2004-03-14 02:03:02 +0000	[diff] [blame]	350
				351	<ul>
Chris Lattner	b5bb597	2004-12-07 08:04:13 +0000	[diff] [blame]	352	<li>The following passes are incomplete or buggy, and may be removed in future
Chris Lattner	38389b1	2005-01-28 06:13:52 +0000	[diff] [blame]	353	releases: <tt>-cee, -branch-combine, -instloops, -paths, -pre</tt></li>
Chris Lattner	b5bb597	2004-12-07 08:04:13 +0000	[diff] [blame]	354	<li>The <tt>llvm-db</tt> tool is in a very early stage of development, but can
				355	be used to step through programs and inspect the stack.</li>
Misha Brukman	9615809	2005-03-30 19:14:24 +0000	[diff] [blame]	356	<li>The "iterative scan" register allocator (enabled with
				357	<tt>-regalloc=iterativescan</tt>) is not stable.</li>
John Criswell	d523492	2005-05-13 20:28:15 +0000	[diff] [blame]	358	<li>The SparcV8, Alpha, and IA64 code generators are experimental.</li>
Chris Lattner	b911de4	2004-03-14 02:03:02 +0000	[diff] [blame]	359	</ul>
				360
				361	</div>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	362
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	363	<!-- ======================================================================= -->
				364	<div class="doc_subsection">
				365	<a name="core">Known problems with the LLVM Core</a>
				366	</div>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	367
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	368	<div class="doc_text">
				369
				370	<ul>
Misha Brukman	9615809	2005-03-30 19:14:24 +0000	[diff] [blame]	371	<li>In the JIT, <tt>dlsym()</tt> on a symbol compiled by the JIT will not
				372	work.</li>
Reid Spencer	493d9c2	2004-11-25 22:38:30 +0000	[diff] [blame]	373	<li>The JIT does not use mutexes to protect its internal data structures. As
				374	such, execution of a threaded program could cause these data structures to be
				375	corrupted.
				376	</li>
Reid Spencer	493d9c2	2004-11-25 22:38:30 +0000	[diff] [blame]	377	<li><a href="http://llvm.cs.uiuc.edu/PR240">The lower-invoke pass does not
				378	mark values live across a setjmp as volatile</a>. This missing feature
				379	only affects targets whose setjmp/longjmp libraries do not save and restore
				380	the entire register file.</li>
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	381	</ul>
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	382	</div>
				383
				384	<!-- ======================================================================= -->
				385	<div class="doc_subsection">
				386	<a name="c-fe">Known problems with the C front-end</a>
				387	</div>
Chris Lattner	178f3db	2003-10-02 05:07:23 +0000	[diff] [blame]	388
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	389	<!-- _______________________________________________________________________ -->
Chris Lattner	5a8a728	2003-12-14 05:03:43 +0000	[diff] [blame]	390	<div class="doc_subsubsection">Bugs</div>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	391
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	392	<div class="doc_text">
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	393	<ul>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	394	<li>C99 Variable sized arrays do not release stack memory when they go out of
				395	scope. Thus, the following program may run out of stack space:
				396	<pre>
				397	for (i = 0; i != 1000000; ++i) {
				398	int X[n];
				399	foo(X);
				400	}
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	401	</pre></li>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	402
Misha Brukman	fa50a22	2004-05-12 21:46:05 +0000	[diff] [blame]	403	<li>Initialization of global union variables can only be done <a
Misha Brukman	68ef9a9	2004-12-04 00:45:09 +0000	[diff] [blame]	404	href="http://llvm.cs.uiuc.edu/PR162">with the largest union member</a>.</li>
Chris Lattner	1ab58dd	2004-03-16 21:39:04 +0000	[diff] [blame]	405
John Criswell	86a3a48	2003-12-18 16:43:17 +0000	[diff] [blame]	406	</ul>
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	407	</div>
				408
				409	<!-- _______________________________________________________________________ -->
				410	<div class="doc_subsubsection">
				411	Notes
				412	</div>
				413
				414	<div class="doc_text">
				415
				416	<ul>
				417
				418	<li>Inline assembly is not yet supported.</li>
Chris Lattner	d2a7427	2003-10-27 18:30:37 +0000	[diff] [blame]	419
				420	<li>"long double" is transformed by the front-end into "double". There is no
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	421	support for floating point data types of any size other than 32 and 64
				422	bits.</li>
				423
				424	<li>The following Unix system functionality has not been tested and may not
				425	work:
Misha Brukman	7cb4e38	2003-11-22 01:00:11 +0000	[diff] [blame]	426	<ol>
				427	<li><tt>sigsetjmp</tt>, <tt>siglongjmp</tt> - These are not turned into the
				428	appropriate <tt>invoke</tt>/<tt>unwind</tt> instructions. Note that
				429	<tt>setjmp</tt> and <tt>longjmp</tt> <em>are</em> compiled correctly.
				430	<li><tt>getcontext</tt>, <tt>setcontext</tt>, <tt>makecontext</tt>
				431	- These functions have not been tested.
				432	</ol></li>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	433
				434	<li>Although many GCC extensions are supported, some are not. In particular,
				435	the following extensions are known to <b>not be</b> supported:
				436	<ol>
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	437	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block.</li>
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	438	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Nested-Functions.html#Nested%20Functions">Nested Functions</a>: As in Algol and Pascal, lexical scoping of functions.</li>
				439	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.</li>
				440	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html#Extended%20Asm">Extended Asm</a>: Assembler instructions with C expressions as operands.</li>
John Criswell	86a3a48	2003-12-18 16:43:17 +0000	[diff] [blame]	441	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands.</li>
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	442	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Asm-Labels.html#Asm%20Labels">Asm Labels</a>: Specifying the assembler name to use for a C symbol.</li>
				443	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Explicit-Reg-Vars.html#Explicit%20Reg%20Vars">Explicit Reg Vars</a>: Defining variables residing in specified registers.</li>
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	444	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Vector-Extensions.html#Vector%20Extensions">Vector Extensions</a>: Using vector instructions through built-in functions.</li>
				445	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Target-Builtins.html#Target%20Builtins">Target Builtins</a>: Built-in functions specific to particular targets.</li>
Tanya Lattner	6337134	2004-12-08 18:25:34 +0000	[diff] [blame]	446	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread_002dLocal.html">Thread-Local</a>: Per-thread variables.</li>
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	447	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pragmas.html#Pragmas">Pragmas</a>: Pragmas accepted by GCC.</li>
Misha Brukman	7cb4e38	2003-11-22 01:00:11 +0000	[diff] [blame]	448	</ol>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	449
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	450	<p>The following GCC extensions are <b>partially</b> supported. An ignored
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	451	attribute means that the LLVM compiler ignores the presence of the attribute,
				452	but the code should still work. An unsupported attribute is one which is
John Criswell	86a3a48	2003-12-18 16:43:17 +0000	[diff] [blame]	453	ignored by the LLVM compiler and will cause a different interpretation of
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	454	the program.</p>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	455
				456	<ol>
				457	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
				458	Arrays whose length is computed at run time.<br>
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	459	Supported, but allocated stack space is not freed until the function returns (noted above).</li>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	460
				461	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	462
John Criswell	86a3a48	2003-12-18 16:43:17 +0000	[diff] [blame]	463	Declaring that functions have no side effects or that they can never
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	464	return.<br>
				465
				466	<b>Supported:</b> <tt>format</tt>, <tt>format_arg</tt>, <tt>non_null</tt>,
John Criswell	6430772	2004-12-08 20:35:47 +0000	[diff] [blame]	467	<tt>noreturn</tt>, <tt>constructor</tt>, <tt>destructor</tt>,
				468	<tt>unused</tt>,
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	469	<tt>deprecated</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
				470
John Criswell	6430772	2004-12-08 20:35:47 +0000	[diff] [blame]	471	<b>Ignored:</b> <tt>noinline</tt>,
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	472	<tt>always_inline</tt>, <tt>pure</tt>, <tt>const</tt>, <tt>nothrow</tt>,
				473	<tt>malloc</tt>, <tt>no_instrument_function</tt>, <tt>cdecl</tt><br>
				474
				475	<b>Unsupported:</b> <tt>used</tt>, <tt>section</tt>, <tt>alias</tt>,
				476	<tt>visibility</tt>, <tt>regparm</tt>, <tt>stdcall</tt>,
				477	<tt>fastcall</tt>, all other target specific attributes</li>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	478
				479	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
				480	Specifying attributes of variables.<br>
				481	<b>Supported:</b> <tt>cleanup</tt>, <tt>common</tt>, <tt>nocommon</tt>,
				482	<tt>deprecated</tt>, <tt>transparent_union</tt>,
				483	<tt>unused</tt>, <tt>weak</tt><br>
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	484
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	485	<b>Unsupported:</b> <tt>aligned</tt>, <tt>mode</tt>, <tt>packed</tt>,
				486	<tt>section</tt>, <tt>shared</tt>, <tt>tls_model</tt>,
				487	<tt>vector_size</tt>, <tt>dllimport</tt>,
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	488	<tt>dllexport</tt>, all target specific attributes.</li>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	489
Misha Brukman	8395d73	2003-12-12 04:37:31 +0000	[diff] [blame]	490	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html#Type%20Attributes">Type Attributes</a>: Specifying attributes of types.<br>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	491	<b>Supported:</b> <tt>transparent_union</tt>, <tt>unused</tt>,
Misha Brukman	8395d73	2003-12-12 04:37:31 +0000	[diff] [blame]	492	<tt>deprecated</tt>, <tt>may_alias</tt><br>
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	493
				494	<b>Unsupported:</b> <tt>aligned</tt>, <tt>packed</tt>,
				495	all target specific attributes.</li>
				496
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	497	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
				498	Other built-in functions.<br>
				499	We support all builtins which have a C language equivalent (e.g.,
				500	<tt>__builtin_cos</tt>), <tt>__builtin_alloca</tt>,
				501	<tt>__builtin_types_compatible_p</tt>, <tt>__builtin_choose_expr</tt>,
Chris Lattner	b7c4bac	2004-06-18 06:26:29 +0000	[diff] [blame]	502	<tt>__builtin_constant_p</tt>, and <tt>__builtin_expect</tt>
				503	(currently ignored). We also support builtins for ISO C99 floating
Chris Lattner	b34b273	2005-05-07 02:21:21 +0000	[diff] [blame]	504	point comparison macros (e.g., <tt>__builtin_islessequal</tt>),
				505	<tt>__builtin_prefetch</tt>, <tt>__builtin_popcount[ll]</tt>,
				506	<tt>__builtin_clz[ll]</tt>, and <tt>__builtin_ctz[ll]</tt>.</li>
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	507	</ol>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	508
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	509	<p>The following extensions <b>are</b> known to be supported:</p>
				510
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	511	<ol>
Chris Lattner	d3dc850	2004-03-16 08:54:07 +0000	[diff] [blame]	512	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Labels-as-Values.html#Labels%20as%20Values">Labels as Values</a>: Getting pointers to labels and computed gotos.</li>
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	513	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.</li>
				514	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Typeof.html#Typeof">Typeof</a>: <code>typeof</code>: referring to the type of an expression.</li>
Tanya Lattner	ce33a1b	2004-06-22 03:48:17 +0000	[diff] [blame]	515	<li><a href="http://gcc.gnu.org/onlinedocs/gcc-3.4.0/gcc/Lvalues.html#Lvalues">Lvalues</a>: Using <code>?:</code>, "<code>,</code>" and casts in lvalues.</li>
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	516	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.</li>
				517	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.</li>
				518	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.</li>
				519	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.</li>
				520	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.</li>
				521	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.</li>
				522	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variadic-Macros.html#Variadic%20Macros">Variadic Macros</a>: Macros with a variable number of arguments.</li>
				523	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.</li>
				524	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Subscripting.html#Subscripting">Subscripting</a>: Any array can be subscripted, even if not an lvalue.</li>
Misha Brukman	8395d73	2003-12-12 04:37:31 +0000	[diff] [blame]	525	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pointer-Arith.html#Pointer%20Arith">Pointer Arith</a>: Arithmetic on <code>void</code>-pointers and function pointers.</li>
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	526	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Initializers.html#Initializers">Initializers</a>: Non-constant initializers.</li>
John Criswell	86a3a48	2003-12-18 16:43:17 +0000	[diff] [blame]	527	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html#Compound%20Literals">Compound Literals</a>: Compound literals give structures, unions,
				528	or arrays as values.</li>
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	529	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html#Designated%20Inits">Designated Inits</a>: Labeling elements of initializers.</li>
Misha Brukman	8395d73	2003-12-12 04:37:31 +0000	[diff] [blame]	530	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Cast-to-Union.html#Cast%20to%20Union">Cast to Union</a>: Casting to union type from any member of the union.</li>
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	531	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.</li>
				532	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.</li>
				533	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions.</li>
Tanya Lattner	7591b82	2004-12-08 18:29:38 +0000	[diff] [blame]	534	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/C_002b_002b-Comments.html#C_002b_002b-Comments">C++ Comments</a>: C++ comments are recognized.</li>
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	535	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.</li>
				536	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Character-Escapes.html#Character%20Escapes">Character Escapes</a>: <code>\e</code> stands for the character <ESC>.</li>
				537	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.</li>
				538	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).</li>
				539	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alternate-Keywords.html#Alternate%20Keywords">Alternate Keywords</a>:<code>__const__</code>, <code>__asm__</code>, etc., for header files.</li>
				540	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Incomplete-Enums.html#Incomplete%20Enums">Incomplete Enums</a>: <code>enum foo;</code>, with details to follow.</li>
				541	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Names.html#Function%20Names">Function Names</a>: Printable strings which are the name of the current function.</li>
Chris Lattner	3646dad	2004-02-14 04:08:29 +0000	[diff] [blame]	542	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Return-Address.html#Return%20Address">Return Address</a>: Getting the return or frame address of a function.</li>
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	543	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Unnamed-Fields.html#Unnamed%20Fields">Unnamed Fields</a>: Unnamed struct/union fields within structs/unions.</li>
				544	<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html#Attribute%20Syntax">Attribute Syntax</a>: Formal syntax for attributes.</li>
Misha Brukman	7cb4e38	2003-11-22 01:00:11 +0000	[diff] [blame]	545	</ol></li>
				546
				547	</ul>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	548
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	549	<p>If you run into GCC extensions which have not been included in any of these
				550	lists, please let us know (also including whether or not they work).</p>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	551
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	552	</div>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	553
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	554	<!-- ======================================================================= -->
				555	<div class="doc_subsection">
				556	<a name="c++-fe">Known problems with the C++ front-end</a>
				557	</div>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	558
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	559	<div class="doc_text">
				560
Reid Spencer	55684c3	2004-12-07 08:39:08 +0000	[diff] [blame]	561	<p>For this release, the C++ front-end is considered to be fully
Chris Lattner	b5bb597	2004-12-07 08:04:13 +0000	[diff] [blame]	562	tested and works for a number of non-trivial programs, including LLVM
				563	itself.</p>
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	564
				565	</div>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	566
				567	<!-- _______________________________________________________________________ -->
Chris Lattner	141ebb6	2004-02-14 04:12:41 +0000	[diff] [blame]	568	<div class="doc_subsubsection">Bugs</div>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	569
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	570	<div class="doc_text">
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	571
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	572	<ul>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	573	<li>The C++ front-end inherits all problems afflicting the <a href="#c-fe">C
John Criswell	86a3a48	2003-12-18 16:43:17 +0000	[diff] [blame]	574	front-end</a>.</li>
Chris Lattner	041e6c9	2004-07-17 02:04:41 +0000	[diff] [blame]	575
Chris Lattner	5cd4092	2004-08-02 20:28:44 +0000	[diff] [blame]	576	<li><b>IA-64 specific</b>: The C++ front-end does not use <a
				577	href="http://llvm.cs.uiuc.edu/PR406">IA64 ABI compliant layout of v-tables</a>.
Chris Lattner	041e6c9	2004-07-17 02:04:41 +0000	[diff] [blame]	578	In particular, it just stores function pointers instead of function
				579	descriptors in the vtable. This bug prevents mixing C++ code compiled with
Chris Lattner	2fd9349	2004-08-02 20:29:51 +0000	[diff] [blame]	580	LLVM with C++ objects compiled by other C++ compilers.</li>
Chris Lattner	041e6c9	2004-07-17 02:04:41 +0000	[diff] [blame]	581
Chris Lattner	5cd4092	2004-08-02 20:28:44 +0000	[diff] [blame]	582	</ul>
				583
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	584	</div>
				585
				586	<!-- _______________________________________________________________________ -->
				587	<div class="doc_subsubsection">
				588	Notes
				589	</div>
				590
				591	<div class="doc_text">
				592
				593	<ul>
Chris Lattner	d2a7427	2003-10-27 18:30:37 +0000	[diff] [blame]	594
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	595	<li>The C++ front-end is based on a pre-release of the GCC 3.4 C++ parser. This
				596	parser is significantly more standards compliant (and picky) than prior GCC
				597	versions. For more information, see the C++ section of the <a
Chris Lattner	e76e9ab	2003-12-12 04:25:33 +0000	[diff] [blame]	598	href="http://gcc.gnu.org/gcc-3.4/changes.html">GCC 3.4 release notes</a>.</li>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	599
				600	<li>Destructors for local objects are not always run when a <tt>longjmp</tt> is
Chris Lattner	6249576	2003-10-02 16:38:05 +0000	[diff] [blame]	601	performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	602	function and in the <tt>setjmp</tt> receiver function may not be run.
John Criswell	86a3a48	2003-12-18 16:43:17 +0000	[diff] [blame]	603	Objects in intervening stack frames will be destroyed, however (which is
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	604	better than most compilers).</li>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	605
Chris Lattner	6249576	2003-10-02 16:38:05 +0000	[diff] [blame]	606	<li>The LLVM C++ front-end follows the <a
				607	href="http://www.codesourcery.com/cxx-abi">Itanium C++ ABI</a>.
				608	This document, which is not Itanium specific, specifies a standard for name
				609	mangling, class layout, v-table layout, RTTI formats, and other C++
				610	representation issues. Because we use this API, code generated by the LLVM
				611	compilers should be binary compatible with machine code generated by other
				612	Itanium ABI C++ compilers (such as G++, the Intel and HP compilers, etc).
				613	<i>However</i>, the exception handling mechanism used by LLVM is very
				614	different from the model used in the Itanium ABI, so <b>exceptions will not
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	615	interact correctly</b>. </li>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	616
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	617	</ul>
Chris Lattner	46ecf61	2003-10-07 22:14:37 +0000	[diff] [blame]	618
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	619	</div>
				620
				621	<!-- ======================================================================= -->
				622	<div class="doc_subsection">
				623	<a name="x86-be">Known problems with the X86 back-end</a>
				624	</div>
				625
				626	<div class="doc_text">
				627
				628	<ul>
John Criswell	d523492	2005-05-13 20:28:15 +0000	[diff] [blame]	629	<li>None yet</li>
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	630	</ul>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	631
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	632	</div>
				633
				634	<!-- ======================================================================= -->
				635	<div class="doc_subsection">
Misha Brukman	a516e99	2004-07-12 16:55:41 +0000	[diff] [blame]	636	<a name="sparcv9-be">Known problems with the SparcV9 back-end</a>
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	637	</div>
				638
				639	<div class="doc_text">
				640
				641	<ul>
Misha Brukman	a516e99	2004-07-12 16:55:41 +0000	[diff] [blame]	642	<li><a href="http://llvm.cs.uiuc.edu/PR60">[sparcv9] SparcV9 backend miscompiles
				643	several programs in the LLVM test suite</a></li>
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	644	</ul>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	645
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	646	</div>
				647
				648	<!-- ======================================================================= -->
				649	<div class="doc_subsection">
Chris Lattner	df925ce	2004-11-07 01:55:32 +0000	[diff] [blame]	650	<a name="ppc-be">Known problems with the PowerPC back-end</a>
				651	</div>
				652
				653	<div class="doc_text">
				654
				655	<ul>
John Criswell	d523492	2005-05-13 20:28:15 +0000	[diff] [blame]	656	<li>None yet</li>
Chris Lattner	df925ce	2004-11-07 01:55:32 +0000	[diff] [blame]	657	</ul>
				658
				659	</div>
				660
				661	<!-- ======================================================================= -->
				662	<div class="doc_subsection">
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	663	<a name="c-be">Known problems with the C back-end</a>
				664	</div>
				665
				666	<div class="doc_text">
				667
				668	<ul>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	669
				670	<li>The C back-end produces code that violates the ANSI C Type-Based Alias
				671	Analysis rules. As such, special options may be necessary to compile the code
				672	(for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	673	problem probably cannot be fixed.</li>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	674
Chris Lattner	c679fbb	2003-11-04 20:06:53 +0000	[diff] [blame]	675	<li><a href="http://llvm.cs.uiuc.edu/PR56">Zero arg vararg functions are not
Chris Lattner	b28c328	2003-10-24 04:03:19 +0000	[diff] [blame]	676	supported</a>. This should not affect LLVM produced by the C or C++
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	677	frontends.</li>
Chris Lattner	b28c328	2003-10-24 04:03:19 +0000	[diff] [blame]	678
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	679	</ul>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	680
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	681	</div>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	682
Andrew Lenharth	2e18c62	2005-05-03 16:59:09 +0000	[diff] [blame]	683	<!-- ======================================================================= -->
				684	<div class="doc_subsection">
				685	<a name="alpha-be">Known problems with the Alpha back-end</a>
				686	</div>
				687
				688	<div class="doc_text">
				689
				690	<ul>
				691
				692	<li>On 21164s, some rare FP arithmatic sequences which may trap do not have the appropriate nops inserted to ensure restartability.</li>
				693
				694	<li>Vararg functions are not supported.</li>
				695
Andrew Lenharth	8ecaa45	2005-05-14 17:43:00 +0000	[diff] [blame]	696	<li>Due to the vararg problems, C++ exceptions do not work. Small changes are required to the CFE (which break correctness in the exception handler) to compile the exception handling library (and thus the C++ standard library).</li>
				697
Andrew Lenharth	2e18c62	2005-05-03 16:59:09 +0000	[diff] [blame]	698	</ul>
				699
				700	</div>
				701
Duraid Madina	9a44900	2005-05-14 05:48:13 +0000	[diff] [blame]	702	<!-- ======================================================================= -->
				703	<div class="doc_subsection">
				704	<a name="ia64-be">Known problems with the IA64 back-end</a>
				705	</div>
				706
				707	<div class="doc_text">
				708
				709	<ul>
				710
				711	<li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are
				712	made where the argument is not 16-byte aligned, as required on IA64. (Strictly
				713	speaking this is not a bug in the IA64 back-end; it will also be encountered
				714	when building C++ programs using the C back-end.)</li>
				715
				716	<li>There are a few ABI violations which will lead to problems
				717	when mixing LLVM output with code built with other compilers,
				718	particularly for C++ and floating-point programs.</li>
				719
				720	<li>Vararg functions are not supported.</li>
				721
				722	</ul>
				723
				724	</div>
				725
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	726	<!-- *********************************************************************** -->
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	727	<div class="doc_section">
				728	<a name="additionalinfo">Additional Information</a>
				729	</div>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	730	<!-- *********************************************************************** -->
				731
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	732	<div class="doc_text">
				733
				734	<p>A wide variety of additional information is available on the LLVM web page,
Misha Brukman	9615809	2005-03-30 19:14:24 +0000	[diff] [blame]	735	including <a href="http://llvm.cs.uiuc.edu/docs/#maillist">mailing lists</a> and
				736	<a href="http://llvm.cs.uiuc.edu/pubs/">publications describing algorithms and
				737	components implemented in LLVM</a>. The web page also contains versions of the
				738	API documentation which is up-to-date with the CVS version of the source code.
				739	You can access versions of these documents specific to this release by going
				740	into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	741
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	742	<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattner	b84f332	2003-12-12 21:22:16 +0000	[diff] [blame]	743	us via the <a href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">mailing
				744	lists</a>.</p>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	745
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	746	</div>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	747
				748	<!-- *********************************************************************** -->
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	749
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	750	<hr>
Misha Brukman	68aab3b	2003-11-22 01:23:39 +0000	[diff] [blame]	751	<address>
Misha Brukman	8834af9	2003-12-21 22:53:21 +0000	[diff] [blame]	752	<a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman	68aab3b	2003-11-22 01:23:39 +0000	[diff] [blame]	753	src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
				754	<a href="http://validator.w3.org/check/referer"><img
				755	src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
				756
Misha Brukman	7cb4e38	2003-11-22 01:00:11 +0000	[diff] [blame]	757	<a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	758	Last modified: $Date$
Misha Brukman	68aab3b	2003-11-22 01:23:39 +0000	[diff] [blame]	759	</address>
Chris Lattner	3d48250	2003-10-02 04:57:28 +0000	[diff] [blame]	760
Misha Brukman	80731b9	2003-11-22 00:38:41 +0000	[diff] [blame]	761	</body>
				762	</html>