Chris Lattner | 79c3fe1 | 2003-10-02 04:57:28 +0000 | [diff] [blame] | 1 | <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> |
| 2 | <html><head><title>LLVM 1.0 Release Notes</title></head> |
| 3 | <body bgcolor=white> |
| 4 | |
| 5 | <table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0> |
| 6 | <tr><td> <font size=+3 color="#EEEEFF" face="Georgia,Palatino,Times,Roman"><b>LLVM 1.0 Release Notes</b></font></td> |
| 7 | </tr></table> |
| 8 | |
| 9 | <ol> |
Chris Lattner | 824b9a6 | 2003-10-02 05:09:46 +0000 | [diff] [blame] | 10 | <li><a href="#intro">Introduction</a> |
Chris Lattner | 79c3fe1 | 2003-10-02 04:57:28 +0000 | [diff] [blame] | 11 | <li><a href="#whatsnew">What's New?</a> |
Chris Lattner | 1909261 | 2003-10-02 16:38:05 +0000 | [diff] [blame] | 12 | <li><a href="#portability">Portability and Supported Platforms</a> |
Chris Lattner | 79c3fe1 | 2003-10-02 04:57:28 +0000 | [diff] [blame] | 13 | <li><a href="#install-instructions">Installation Instructions</a> |
| 14 | <li><a href="#knownproblems">Known Problems</a> |
| 15 | <ul> |
Chris Lattner | 1909261 | 2003-10-02 16:38:05 +0000 | [diff] [blame] | 16 | <!-- <li><a href="#portabilityprobs">Portability Problems</a> --> |
Chris Lattner | 79c3fe1 | 2003-10-02 04:57:28 +0000 | [diff] [blame] | 17 | <li><a href="#core">Known problems with the LLVM Core</a> |
| 18 | <li><a href="#c-fe">Known problems with the C Front-end</a> |
| 19 | <li><a href="#c++-fe">Known problems with the C++ Front-end</a> |
| 20 | <li><a href="#x86-be">Known problems with the X86 Back-end</a> |
| 21 | <li><a href="#sparc-be">Known problems with the Sparc Back-end</a> |
| 22 | <li><a href="#c-be">Known problems with the C back-end</a> |
| 23 | </ul> |
| 24 | <li><a href="#additionalinfo">Additional Information</a> |
| 25 | </ul> |
| 26 | |
| 27 | <p><b>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a></b><p> |
| 28 | </ol> |
| 29 | |
| 30 | |
| 31 | <!-- *********************************************************************** --> |
| 32 | <table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0> |
| 33 | <tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b> |
| 34 | <a name="intro">Introduction |
| 35 | </b></font></td></tr></table><ul> |
| 36 | <!-- *********************************************************************** --> |
| 37 | |
| 38 | This document contains the release notes for the LLVM compiler infrastructure, |
Chris Lattner | 47ad72c | 2003-10-07 21:38:31 +0000 | [diff] [blame^] | 39 | release 1.0. Here we describe how to install LLVM, as well as any known |
| 40 | problems. The most up-to-date version of this document can be found on the <a |
| 41 | href="http://llvm.cs.uiuc.edu/releases/1.0/">LLVM 1.0 web site</a>. If you are |
| 42 | not reading this on the LLVM web pages, you should probably go there, because |
| 43 | this document may be updated after the release.<p> |
Chris Lattner | 1909261 | 2003-10-02 16:38:05 +0000 | [diff] [blame] | 44 | |
Chris Lattner | 47ad72c | 2003-10-07 21:38:31 +0000 | [diff] [blame^] | 45 | For more information about LLVM, including information about potentially more |
| 46 | current releases, please check out the <a href="http://llvm.cs.uiuc.edu">main |
| 47 | web site</a>. If you have questions or comments, the <a |
| 48 | href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing |
| 49 | list</a> is a good place to send them.<p> |
Chris Lattner | 79c3fe1 | 2003-10-02 04:57:28 +0000 | [diff] [blame] | 50 | |
| 51 | |
| 52 | <!-- *********************************************************************** --> |
| 53 | </ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0> |
| 54 | <tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b> |
| 55 | <a name="whatsnew">What's New? |
| 56 | </b></font></td></tr></table><ul> |
| 57 | <!-- *********************************************************************** --> |
| 58 | |
| 59 | This is the first public release of the LLVM compiler infrastructure. As such, |
| 60 | it is all new! In particular, we are providing a stable C compiler, beta C++ |
| 61 | compiler, a C back-end, stable X86 and Sparc V9 static and JIT code generators, |
| 62 | as well as a large suite of scalar and interprocedural optimizations.<p> |
| 63 | |
Chris Lattner | 47ad72c | 2003-10-07 21:38:31 +0000 | [diff] [blame^] | 64 | The default optimizer sequence used by the C/C++ front-ends is:<p> |
| 65 | |
| 66 | <ol> |
| 67 | <li>Interprocedural dead code elimination (-globaldce) |
| 68 | <li>Exception handling pruning (-prune-eh) |
| 69 | <li>Function inlining (-inline) |
| 70 | <li>Instruction combining (-instcombine) |
| 71 | <li>Cast elimination (-raise) |
| 72 | <li>Tail duplication (-tailduplicate) |
| 73 | <li>CFG simplification (-simplifycfg) |
| 74 | <li>Scalar replacement of aggregates (-scalarrepl) |
| 75 | <li>Tail call elimination (-tailcallelim) |
| 76 | <li>Instruction combining (-instcombine) |
| 77 | <li>Reassociation (-reassociate) |
| 78 | <li>Instruction combining (-instcombine) |
| 79 | <li>CFG simplification (-simplifycfg) |
| 80 | <li>Loop canonnicalization (-preheaders) |
| 81 | <li>Loop invariant code motion, with scalar promotion (-licm) |
| 82 | <li>Global common subexpression elimination, with load elimination (-gcse) |
| 83 | <li>Sparse conditional constant propagation (-sccp) |
| 84 | <li>Instruction combining (-instcombine) |
| 85 | <li>Induction variable canonicalization (-indvars) |
| 86 | <li>Aggressive dead code elimination (-adce) |
| 87 | <li>CFG simplication (-simplifycfg) |
| 88 | <li>Dead type elimination (-deadtypeelim) |
| 89 | <li>Global constant merging (-constmerge) |
| 90 | </ol><p> |
| 91 | |
| 92 | At link-time, the following optimizations are run:<p> |
| 93 | |
| 94 | <ol> |
| 95 | <li>Global constant merging (-constmerge) |
| 96 | <li>[optional] Internalization [which marks most functions and global variables static] (-internalize) |
| 97 | <li>Interprocedural dead argument elimination (-deadargelim) |
| 98 | <li>Instruction combining (-instcombine) |
| 99 | <li>CFG simplification (-simplifycfg) |
| 100 | <li>Interprocedural dead code elimination (-globaldce) |
| 101 | </ol><p> |
| 102 | |
| 103 | |
Chris Lattner | 79c3fe1 | 2003-10-02 04:57:28 +0000 | [diff] [blame] | 104 | TODO: Works on: SPEC CPU 2000<p> |
Chris Lattner | 1909261 | 2003-10-02 16:38:05 +0000 | [diff] [blame] | 105 | TODO: Works on: Olden/Ptrdist benchmarks<p> |
| 106 | |
| 107 | The What's New section should give a bulletted list of what is |
| 108 | included, perhaps a couple of lists (Stable, Beta).<p> |
| 109 | |
| 110 | It would be useful to give a pointer to a list of the available passes (at least |
| 111 | for the standard compiler techniques).<p> |
| 112 | |
| 113 | |
| 114 | <!-- *********************************************************************** --> |
| 115 | </ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0> |
| 116 | <tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b> |
| 117 | <a name="portability">Portability and Supported Platforms |
| 118 | </b></font></td></tr></table><ul> |
| 119 | <!-- *********************************************************************** --> |
| 120 | |
| 121 | LLVM has only been extensively tested on ia32-linux and sparc-solaris machines. |
| 122 | The core LLVM infrastructure uses "autoconf" for portability, so hopefully we |
| 123 | work on more platforms than that. However, it is extremely likely that we |
| 124 | missed something. We welcome portability patches and error messages.<p> |
Chris Lattner | 79c3fe1 | 2003-10-02 04:57:28 +0000 | [diff] [blame] | 125 | |
| 126 | |
| 127 | <!-- *********************************************************************** --> |
| 128 | </ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0> |
| 129 | <tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b> |
| 130 | <a name="install-instructions">Installation Instructions |
| 131 | </b></font></td></tr></table><ul> |
| 132 | <!-- *********************************************************************** --> |
| 133 | |
| 134 | FIXME |
| 135 | |
| 136 | |
| 137 | <!-- *********************************************************************** --> |
| 138 | </ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0> |
| 139 | <tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b> |
| 140 | <a name="knownproblems">Known Problems |
| 141 | </b></font></td></tr></table><ul> |
| 142 | <!-- *********************************************************************** --> |
| 143 | |
| 144 | This section contains all known problems with the LLVM system, listed by |
| 145 | component. As new problems are discovered, they will be added to these |
Chris Lattner | 1909261 | 2003-10-02 16:38:05 +0000 | [diff] [blame] | 146 | sections. |
Chris Lattner | 79c3fe1 | 2003-10-02 04:57:28 +0000 | [diff] [blame] | 147 | |
| 148 | |
| 149 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 1909261 | 2003-10-02 16:38:05 +0000 | [diff] [blame] | 150 | <!-- |
Chris Lattner | 79c3fe1 | 2003-10-02 04:57:28 +0000 | [diff] [blame] | 151 | </ul><h4><a name="portability"><hr size=0>Portability Problems</h4><ul> |
Chris Lattner | 1909261 | 2003-10-02 16:38:05 +0000 | [diff] [blame] | 152 | --> |
Chris Lattner | 79c3fe1 | 2003-10-02 04:57:28 +0000 | [diff] [blame] | 153 | |
| 154 | |
| 155 | <!-- _______________________________________________________________________ --> |
| 156 | </ul><h4><a name="core"><hr size=0>Known problems with the LLVM Core</h4><ul> |
| 157 | |
| 158 | <li>In the JIT, <tt>dlsym</tt> on a symbol compiled by the JIT will not work.<p> |
| 159 | |
| 160 | <li>The JIT does not use mutexes to protect its internal data structures. As |
| 161 | such, execution of a threaded program could cause these data structures to |
| 162 | be corrupted.<p> |
| 163 | |
| 164 | <li>It is not possible to <tt>dlopen</tt> an LLVM bytecode file in the JIT.<p> |
| 165 | |
Chris Lattner | 47588f9 | 2003-10-02 05:07:23 +0000 | [diff] [blame] | 166 | <li>Linking in static archive files (.a files) is very slow. |
| 167 | |
Chris Lattner | 79c3fe1 | 2003-10-02 04:57:28 +0000 | [diff] [blame] | 168 | <!-- _______________________________________________________________________ --> |
| 169 | </ul><h4><a name="c-fe"><hr size=0>Known problems with the C front-end</h4><ul> |
| 170 | |
| 171 | <li>Inline assembly is not yet supported.<p> |
| 172 | |
| 173 | <li>"long double" is transformed by the front-end into "double". There is no |
Chris Lattner | 1909261 | 2003-10-02 16:38:05 +0000 | [diff] [blame] | 174 | support for floating point data types of any size other than 32 and 64 bits. |
| 175 | <p> |
Chris Lattner | 79c3fe1 | 2003-10-02 04:57:28 +0000 | [diff] [blame] | 176 | <li>C99 Variable sized arrays do not release stack memory when they go out of |
| 177 | scope. Thus, the following program may run out of stack space: |
| 178 | <pre> |
| 179 | for (i = 0; i != 1000000; ++i) { |
| 180 | int X[n]; |
| 181 | foo(X); |
| 182 | } |
| 183 | </pre><p> |
| 184 | |
Chris Lattner | 824b9a6 | 2003-10-02 05:09:46 +0000 | [diff] [blame] | 185 | <li>The following Unix system functionality has not been tested and may not work: |
Chris Lattner | 79c3fe1 | 2003-10-02 04:57:28 +0000 | [diff] [blame] | 186 | <ol> |
| 187 | <li><tt>sigsetjmp</tt>, <tt>siglongjmp</tt> - These are not turned into the |
| 188 | appropriate <tt>invoke</tt>/<tt>unwind</tt> instructions. |
| 189 | <li><tt>getcontext</tt>, <tt>setcontext</tt>, <tt>makecontext</tt> |
| 190 | - These functions have not been tested. |
| 191 | </ol><p> |
| 192 | |
| 193 | <li>Although many GCC extensions are supported, some are not. In particular, |
| 194 | the following extensions are known to <b>not be</b> supported: |
| 195 | <ol> |
| 196 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block. |
| 197 | <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. |
| 198 | <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. |
| 199 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function. |
| 200 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html#Extended%20Asm">Extended Asm</a>: Assembler instructions with C expressions as operands. |
| 201 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands |
| 202 | <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. |
| 203 | <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. |
| 204 | <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. |
| 205 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Vector-Extensions.html#Vector%20Extensions">Vector Extensions</a>: Using vector instructions through built-in functions. |
| 206 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Target-Builtins.html#Target%20Builtins">Target Builtins</a>: Built-in functions specific to particular targets. |
| 207 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread-Local.html#Thread-Local">Thread-Local</a>: Per-thread variables. |
| 208 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pragmas.html#Pragmas">Pragmas</a>: Pragmas accepted by GCC. |
| 209 | </ol><p> |
| 210 | |
| 211 | The following GCC extensions are <b>partially</b> supported. An ignored |
| 212 | attribute means that the LLVM compiler ignores the presence of the attribute, |
| 213 | but the code should still work. An unsupported attribute is one which is |
| 214 | ignored by the LLVM compiler, which will cause a different interpretation of |
| 215 | the program.<p> |
| 216 | |
| 217 | <ol> |
| 218 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>: |
| 219 | Arrays whose length is computed at run time.<br> |
| 220 | Supported, but allocated stack space is not freed until the function returns (noted above). |
| 221 | |
| 222 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>: |
| 223 | Declaring that functions have no side effects, or that they can never return.<br> |
| 224 | <b>Supported:</b> <tt>format</tt>, <tt>format_arg</tt>, <tt>non_null</tt>, <tt>constructor</tt>, <tt>destructor</tt>, <tt>unused</tt>, <tt>deprecated</tt>, |
| 225 | <tt>warn_unused_result</tt>, <tt>weak</tt><br> |
| 226 | <b>Ignored:</b> <tt>noreturn</tt>, <tt>noinline</tt>, <tt>always_inline</tt>, <tt>pure</tt>, <tt>const</tt>, <tt>nothrow</tt>, <tt>malloc</tt> |
| 227 | <tt>no_instrument_function</tt>, <tt>cdecl</tt><br> |
| 228 | <b>Unsupported:</b> <tt>used</tt>, <tt>section</tt>, <tt>alias</tt>, <tt>visibility</tt>, <tt>regparm</tt>, <tt>stdcall</tt>, |
| 229 | <tt>fastcall</tt>, all other target specific attributes |
| 230 | |
| 231 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>: |
| 232 | Specifying attributes of variables.<br> |
| 233 | <b>Supported:</b> <tt>cleanup</tt>, <tt>common</tt>, <tt>nocommon</tt>, |
| 234 | <tt>deprecated</tt>, <tt>transparent_union</tt>, |
| 235 | <tt>unused</tt>, <tt>weak</tt><br> |
| 236 | <b>Unsupported:</b> <tt>aligned</tt>, <tt>mode</tt>, <tt>packed</tt>, |
| 237 | <tt>section</tt>, <tt>shared</tt>, <tt>tls_model</tt>, |
| 238 | <tt>vector_size</tt>, <tt>dllimport</tt>, |
| 239 | <tt>dllexport</tt>, all target specific attributes.<br> |
| 240 | |
| 241 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html#Type%20Attributes">Type Attributes</a>: Specifying attributes of types. |
| 242 | <b>Supported:</b> <tt>transparent_union</tt>, <tt>unused</tt>, |
| 243 | <tt>deprecated</tt>, <tt>may_alias</tt> |
| 244 | <b>Unsupported:</b> <tt>aligned</tt>, <tt>packed</tt> |
| 245 | all target specific attributes.<br> |
| 246 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>: |
| 247 | Other built-in functions.<br> |
| 248 | We support all builtins which have a C language equivalent (e.g., |
| 249 | <tt>__builtin_cos</tt>), <tt>__builtin_alloca</tt>, |
| 250 | <tt>__builtin_types_compatible_p</tt>, <tt>__builtin_choose_expr</tt>, |
| 251 | <tt>__builtin_constant_p</tt>, and <tt>__builtin_expect</tt> (ignored). |
| 252 | </ol><p> |
| 253 | |
| 254 | |
| 255 | The following extensions <b>are</b> known to be supported: |
| 256 | <ol> |
| 257 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions. |
| 258 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Typeof.html#Typeof">Typeof</a>: <code>typeof</code>: referring to the type of an expression. |
Chris Lattner | 1909261 | 2003-10-02 16:38:05 +0000 | [diff] [blame] | 259 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Lvalues.html#Lvalues">Lvalues</a>: Using <code>?:</code>, "<code>,</code>" and casts in lvalues. |
Chris Lattner | 79c3fe1 | 2003-10-02 04:57:28 +0000 | [diff] [blame] | 260 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression. |
| 261 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers. |
| 262 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers. |
| 263 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants. |
| 264 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays. |
| 265 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members. |
| 266 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variadic-Macros.html#Variadic%20Macros">Variadic Macros</a>: Macros with a variable number of arguments. |
| 267 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines. |
| 268 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Subscripting.html#Subscripting">Subscripting</a>: Any array can be subscripted, even if not an lvalue. |
| 269 | <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. |
| 270 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Initializers.html#Initializers">Initializers</a>: Non-constant initializers. |
| 271 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html#Compound%20Literals">Compound Literals</a>: Compound literals give structures, unions or arrays as values. |
| 272 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html#Designated%20Inits">Designated Inits</a>: Labeling elements of initializers. |
| 273 | |
| 274 | <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. |
| 275 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such. |
| 276 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code. |
| 277 | |
| 278 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions. |
| 279 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/C---Comments.html#C++%20Comments">C++ Comments</a>: C++ comments are recognized. |
| 280 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers. |
| 281 | <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>. |
| 282 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable. |
| 283 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros). |
| 284 | <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. |
| 285 | <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. |
| 286 | <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. |
| 287 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Unnamed-Fields.html#Unnamed%20Fields">Unnamed Fields</a>: Unnamed struct/union fields within structs/unions. |
| 288 | <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html#Attribute%20Syntax">Attribute Syntax</a>: Formal syntax for attributes. |
| 289 | </ol><p> |
| 290 | |
| 291 | If you run into GCC extensions which have not been included in any of these |
| 292 | lists, please let us know (also including whether or not they work). |
| 293 | |
| 294 | |
| 295 | <!-- _______________________________________________________________________ --> |
| 296 | </ul><h4><a name="c++-fe"><hr size=0>Known problems with the C++ front-end</h4><ul> |
| 297 | |
| 298 | For this release, the C++ front-end is considered to be of <b>beta</b> quality. |
| 299 | It works for a large number of simple programs, but has not been extensively |
| 300 | tested. We welcome bug reports though!<p> |
| 301 | |
| 302 | <li>The C++ front-end inherits all problems afflicting the <a href="#c-fe">C |
| 303 | front-end</a><p> |
| 304 | |
| 305 | <li>The C++ front-end is based on a pre-release of the GCC 3.4 C++ parser. This |
| 306 | parser is significantly more standards compliant (and picky) than prior GCC |
| 307 | versions. For more information, see the C++ section of the <a |
| 308 | href="http://gcc.gnu.org/gcc-3.4/changes.html">GCC 3.4 release notes</a>.<p> |
| 309 | |
| 310 | <li>Destructors for local objects are not always run when a <tt>longjmp</tt> is |
Chris Lattner | 1909261 | 2003-10-02 16:38:05 +0000 | [diff] [blame] | 311 | performed. In particular, destructors for objects in the <tt>longjmp</tt>ing |
Chris Lattner | 79c3fe1 | 2003-10-02 04:57:28 +0000 | [diff] [blame] | 312 | function and in the <tt>setjmp</tt> receiver function may not be run. |
| 313 | Objects in intervening stack frames will be destroyed however (which is |
| 314 | better than most compilers).<p> |
| 315 | |
Chris Lattner | 1909261 | 2003-10-02 16:38:05 +0000 | [diff] [blame] | 316 | <li>The LLVM C++ front-end follows the <a |
| 317 | href="http://www.codesourcery.com/cxx-abi">Itanium C++ ABI</a>. |
| 318 | This document, which is not Itanium specific, specifies a standard for name |
| 319 | mangling, class layout, v-table layout, RTTI formats, and other C++ |
| 320 | representation issues. Because we use this API, code generated by the LLVM |
| 321 | compilers should be binary compatible with machine code generated by other |
| 322 | Itanium ABI C++ compilers (such as G++, the Intel and HP compilers, etc). |
| 323 | <i>However</i>, the exception handling mechanism used by LLVM is very |
| 324 | different from the model used in the Itanium ABI, so <b>exceptions will not |
| 325 | interact correctly</b> . |
Chris Lattner | 79c3fe1 | 2003-10-02 04:57:28 +0000 | [diff] [blame] | 326 | |
| 327 | <!-- _______________________________________________________________________ --> |
| 328 | </ul><h4><a name="x86-be"><hr size=0>Known problems with the X86 back-end</h4><ul> |
| 329 | |
| 330 | <li>The X86 code generator does not currently support the <tt>unwind</tt> |
| 331 | instruction, so code that throws a C++ exception or calls the C <tt>longjmp</tt> |
| 332 | function will abort.<p> |
| 333 | |
| 334 | <li>Some executables produced by LLC seem to intermittently crash (extremely |
| 335 | infrequently). The cause of the problem has not been diagnosed, and does not |
| 336 | affect the JIT.<p> |
| 337 | |
| 338 | |
| 339 | <!-- _______________________________________________________________________ --> |
| 340 | </ul><h4><a name="sparc-be"><hr size=0>Known problems with the Sparc back-end</h4><ul> |
| 341 | |
Chris Lattner | 35fccb7 | 2003-10-05 19:17:10 +0000 | [diff] [blame] | 342 | <li>The Sparc code generator does not currently support the <tt>unwind</tt> |
| 343 | instruction, so code that throws a C++ exception or calls the C <tt>longjmp</tt> |
| 344 | function will abort.<p> |
Chris Lattner | 79c3fe1 | 2003-10-02 04:57:28 +0000 | [diff] [blame] | 345 | |
| 346 | |
| 347 | <!-- _______________________________________________________________________ --> |
| 348 | </ul><h4><a name="c-be"><hr size=0>Known problems with the C back-end</h4><ul> |
| 349 | |
| 350 | <li>The C back-end produces code that violates the ANSI C Type-Based Alias |
| 351 | Analysis rules. As such, special options may be necessary to compile the code |
| 352 | (for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This |
| 353 | problem probably cannot be fixed.<p> |
| 354 | |
| 355 | <li>Initializers for global variables that include floating point numbers may |
| 356 | not be initialized with exactly the right floating point number, if the number |
| 357 | is not accurately representable in decimal. This prevents the Olden "power" |
Chris Lattner | 824b9a6 | 2003-10-02 05:09:46 +0000 | [diff] [blame] | 358 | benchmark from producing exactly the right results with the C back-end.<p> |
Chris Lattner | 79c3fe1 | 2003-10-02 04:57:28 +0000 | [diff] [blame] | 359 | |
| 360 | <li>The code produces by the C back-end has only been tested with the Sun CC and |
| 361 | GCC compilers. It is possible that it will have to be adjusted to support other |
| 362 | C compilers.<p> |
| 363 | |
| 364 | |
| 365 | |
| 366 | <!-- *********************************************************************** --> |
| 367 | </ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0> |
| 368 | <tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b> |
| 369 | <a name="additionalinfo">Additional Information |
| 370 | </b></font></td></tr></table><ul> |
| 371 | <!-- *********************************************************************** --> |
| 372 | |
| 373 | A wide variety of additional information is available on the LLVM web page, |
| 374 | including mailing lists publications describing algorithms and components |
| 375 | implemented in LLVM. The web page also contains versions of the API |
| 376 | documentation which is up-to-date with the CVS version of the source code. You |
| 377 | can access versions of these documents specific to this release by going into |
| 378 | the "<tt>llvm/www/doc/</tt>" directory in the LLVM tree.<p> |
| 379 | |
| 380 | If you have any questions or comments about LLVM, please feel free to contact us |
| 381 | via the mailing lists.<p> |
| 382 | |
| 383 | |
| 384 | <!-- *********************************************************************** --> |
| 385 | </ul> |
| 386 | <!-- *********************************************************************** --> |
| 387 | |
| 388 | <hr><font size-1> |
| 389 | |
Chris Lattner | 47ad72c | 2003-10-07 21:38:31 +0000 | [diff] [blame^] | 390 | Maintained By: <a href="http://llvm.cs.uiuc.edu/">The LLVM Team</a><br> |
Chris Lattner | 79c3fe1 | 2003-10-02 04:57:28 +0000 | [diff] [blame] | 391 | <!-- Created: Wed Oct 1 17:38:54 CDT 2003 --> |
| 392 | <!-- hhmts start --> |
Chris Lattner | 47ad72c | 2003-10-07 21:38:31 +0000 | [diff] [blame^] | 393 | Last modified: Tue Oct 7 16:32:37 CDT 2003 |
Chris Lattner | 79c3fe1 | 2003-10-02 04:57:28 +0000 | [diff] [blame] | 394 | <!-- hhmts end --> |
| 395 | </body></html> |