<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<link rel="stylesheet" href="llvm.css" type="text/css">
- <title>LLVM 1.7 Release Notes</title>
+ <title>LLVM 1.9 Release Notes</title>
</head>
<body>
-<div class="doc_title">LLVM 1.7 Release Notes</div>
+<div class="doc_title">LLVM 1.9 Release Notes</div>
<ol>
<li><a href="#intro">Introduction</a></li>
<div class="doc_text">
<p>This document contains the release notes for the LLVM compiler
-infrastructure, release 1.7. Here we describe the status of LLVM, including any
+infrastructure, release 1.9. Here we describe the status of LLVM, including any
known problems and major improvements from the previous release. The most
-up-to-date version of this document can be found on the <a
+up-to-date version of this document (corresponding to LLVM CVS) can be found
+on the <a
href="http://llvm.org/releases/">LLVM releases web site</a>. If you are
not reading this on the LLVM web pages, you should probably go there because
this document may be updated after the release.</p>
<div class="doc_text">
-<p>This is the eighth public release of the LLVM Compiler Infrastructure. This
-release incorporates a large number of enhancements and new features,
-including vector support (Intel SSE and Altivec), a new GCC4.0-based
-C/C++ front-end, Objective C/C++ support, inline assembly support, and many
-other big features.
+<p>This is the tenth public release of the LLVM Compiler Infrastructure. This
+release incorporates a large number of enhancements, new features, and bug
+fixes. We recommend that all users of previous LLVM versions upgrade.
</p>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="newfeatures">New Features in LLVM 1.7</a>
+<a name="newfeatures">New Features in LLVM 1.9</a>
</div>
<!--_________________________________________________________________________-->
-<div class="doc_subsubsection"><a name="llvmgcc4">GCC4.0-based llvm-gcc
-front-end</a></div>
-
+<div class="doc_subsubsection"><a name="x86-64">New X86-64 Backend</a></div>
<div class="doc_text">
-
-<p>LLVM 1.8 includes a brand new llvm-gcc, based on GCC 4.0.1. This version
-of llvm-gcc solves many serious long-standing problems with llvm-gcc, including
-all of those blocked by the <a href="http://llvm.org/PR498">llvm-gcc 4 meta
-bug</a>. In addition, llvm-gcc4 implements support for many new features,
-including GCC inline assembly, generic vector support, SSE and Altivec
-intrinsics, and several new GCC attributes. In addition, llvm-gcc4 is
-significantly faster than llvm-gcc3, respects -O options, its -c/-S options
-correspond to GCC's (they emit native code).</p>
-
-<p>If you can use it, llvm-gcc4 is offers significant new functionality, and we
-hope that it will replace llvm-gcc3 completely in a future release.
-Unfortunately, it does not currently support C++ exception handling at all, and
-it only works on Apple Mac OS/X machines with X86 or PowerPC processors.
-</p>
-
+<p>LLVM 1.9 now fully supports the x86-64 instruction set on Mac OS/X, and
+supports it on Linux (and other operating systems) when compiling in -static
+mode. LLVM includes JIT support for X86-64, and supports both Intel EMT-64T
+and AMD-64 architectures. The X86-64 instruction set permits addressing a
+64-bit addressing space and provides the compiler with twice the
+number of integer registers to use.</p>
</div>
<!--_________________________________________________________________________-->
-<div class="doc_subsubsection"><a name="inlineasm">Inline Assembly
-Support</a></div>
-
+<div class="doc_subsubsection"><a name="lto">Link-Time Optimization integration
+with native linkers</a></div>
<div class="doc_text">
-
-<p>The LLVM IR and llvm-gcc4 front-end now fully support arbitrary GCC <a
-href="LangRef.html#inlineasm">inline assembly</a>. The LLVM X86 and PowerPC
-code generators have initial support for it,
-being able to compile basic statements, but are missing some features. Please
-report any inline asm statements that crash the compiler or that are miscompiled
-as bugs.</p>
-
+<p>LLVM now includes <a href="LinkTimeOptimization.html">liblto</a> which can
+be used to integrate LLVM Link-Time Optimization support into a native linker.
+This allows LLVM .bc to transparently participate with linking an application,
+even when some .o files are in LLVM form and some are not.</p>
</div>
<!--_________________________________________________________________________-->
-<div class="doc_subsubsection"><a name="newsparc">New SPARC backend</a></div>
-
+<div class="doc_subsubsection"><a name="dwarf">DWARF debugging
+support for Linux, Cygwin and MinGW on X86</a></div>
<div class="doc_text">
-
-<p>LLVM 1.7 includes a new, fully functional, SPARC backend built in the
-target-independent code generator. This SPARC backend includes support for
-SPARC V8 and SPARC V9 subtargets (controlling whether V9 features can be used),
-and targets the 32-bit SPARC ABI.</p>
-
-<p>The LLVM 1.7 release is the last release that will include the LLVM "SparcV9"
-backend, which was the very first LLVM native code generator. In 1.8, it will
-be removed, replaced with the new SPARC backend.</p>
-
+<p>llvm-gcc4 now supports generating debugging info for Linux, Cygwin and MinGW.
+This extends the PPC/Darwin and X86/Darwin debugging support available in the
+1.8 release. DWARF is a standard debugging format used on many platforms.</p>
</div>
<!--_________________________________________________________________________-->
-<div class="doc_subsubsection"><a name="genvector">Generic Vector Support
-</a></div>
-
+<div class="doc_subsubsection"><a name="optimizer">Optimizer
+Improvements</a></div>
<div class="doc_text">
+<p>The mid-level optimizer is now faster and produces better code in many cases.
+ Significant changes include:</p>
-<p>LLVM now includes significantly extended support for SIMD vectors in its
-core instruction set. It now includes three new instructions for manipulating
-vectors: <a href="LangRef.html#i_extractelement"><tt>extractelement</tt></a>,
-<a href="LangRef.html#i_insertelement"><tt>insertelement</tt></a>, and
-<a href="LangRef.html#i_shufflevector"><tt>shufflevector</tt></a>. Further,
-many bugs in vector handling have been fixed, and vectors are now supported by
-the target-independent code generator. For example, if a vector operation is
-not supported by a particular target, it will be correctly broken down and
-executed as scalar operations.</p>
-
-<p>Because llvm-gcc3 does not support GCC generic vectors or vector intrinsics,
-so llvm-gcc4 must be used.</p>
+<ul>
+<li>LLVM includes a new 'predicate simplifier' pass, which
+ currently performs dominator tree-based optimizations.</li>
+<li>The complete loop unroll pass now supports unrolling of
+ multiple basic block loops.</li>
+<li>The 'globalopt' pass can now perform the scalar replacement of
+ aggregates transformation on some heap allocations.</li>
+<li>The globalsmodref-aa alias analysis can now track 'indirect pointer
+ globals' more accurately.</li>
+<li>The instruction combiner can now perform element propagation
+analysis of vector expressions, eliminating computation of vector elements
+that are not used.</li>
+</ul>
+
</div>
-
<!--_________________________________________________________________________-->
-<div class="doc_subsubsection"><a name="ssealtivec">Intel SSE and PowerPC
-Altivec support
-</a></div>
+<div class="doc_subsubsection"><a name="codegen">Code
+Generator Enhancements</a></div>
<div class="doc_text">
-
-<p>The LLVM X86 backend now supports Intel SSE 1, 2, and 3, and now uses scalar
-SSE operations to implement scalar floating point math when the target supports
-SSE1 (for floats) or SSE2 (for doubles). Vector SSE instructions are generated
-by llvm-gcc4 when the generic vector mechanism or specific SSE intrinsics are
-used.
+<p>
+The LLVM Target-Independent code generator now supports more target features and
+optimizes many cases more aggressively. New features include:
</p>
-<p>The LLVM PowerPC backend now supports the Altivec instruction set, including
-both GCC -maltivec and -faltivec modes. Altivec instructions are generated
-by llvm-gcc4 when the generic vector mechanism or specific Altivec intrinsics
-are used.
-</p>
+<ul>
+<li>LLVM now includes a late branch folding pass which optimizes code
+ layout, performs several branch optzns, and deletes unreachable code.</li>
+<li>The code generator now support targets that have pre/post-increment
+ addressing modes.</li>
+<li>LLVM now supports dynamically-loadable register allocators and
+ schedulers.</li>
+<li>LLVM 1.9 includes several improvements to inline asm support,
+ including support for new constraints and modifiers.</li>
+<li>The register coalescer is now more aggressive than before,
+ allowing it to eliminate more copies.</li>
+</ul>
-</div>
+<p>In addition, the LLVM target description format has itself been extended in
+ several ways:</p>
+
+<ul>
+<li>tblgen now allows definition of '<a
+ href="TableGenFundamentals.html#multiclass">multiclasses</a>' which can be
+ used to factor instruction patterns more aggressively in .td files.</li>
+<li>LLVM has a new TargetAsmInfo class which captures a variety of
+ information about the target assembly language format.</li>
+<li>.td files now support "<tt>${:foo}</tt>" syntax for encoding
+ subtarget-specific assembler syntax into instruction descriptions.</li>
+</ul>
-<!--_________________________________________________________________________-->
-<div class="doc_subsubsection"><a name="othernew">Optimizer
-Improvements</a></div>
+<p>Further, several significant target-specific enhancements are included in
+LLVM 1.9:</p>
-<div class="doc_text">
<ul>
-<li>The Loop Unswitching pass (<tt>-loop-unswitch</tt>) has had several bugs
- fixed, has several new features, and is enabled by default in llvmgcc3
- now.</li>
-<li>The Loop Strength Reduction pass (<tt>-loop-reduce</tt>) is now enabled for
- the X86 backend.</li>
-<li>The Instruction Combining pass (<tt>-instcombine</tt>) now includes a
- framework and implementation for simplifying code based on whether computed
- bits are demanded or not.</li>
-<li>The Scalar Replacement of Aggregates pass (<tt>-scalarrepl</tt>) can now
- promote simple unions to registers.</li>
-<li>Several LLVM passes are <a href="http://llvm.org/PR681">significantly
-faster</a>.</li>
+<li>The LLVM ARM backend now supports more instructions
+ and the use of a frame pointer. It is now possible to build
+ libgcc and a simple cross compiler, but it is not considered "complete" yet.
+ </li>
+<li>LLVM supports the Win32 dllimport/dllexport linkage and
+ stdcall/fastcall calling conventions.</li>
</ul>
-</div>
+</div>
<!--_________________________________________________________________________-->
-<div class="doc_subsubsection"><a name="othernew">Other New Features</a></div>
-
+<div class="doc_subsubsection"><a name="other">Other Improvements</a></div>
<div class="doc_text">
-<ul>
-<li>LLVM now supports first class global ctor/dtor initialization lists, no
- longer forcing targets to use "__main".</li>
-<li>LLVM supports assigning globals and functions to a particular section
- in the result executable using the GCC section attribute.</li>
-<li><a href="ExtendingLLVM.html">Adding intrinsics to LLVM</a> is now
-significantly easier.</li>
-<li>llvmgcc4 now fully supports C99 Variable Length Arrays, including dynamic
- stack deallocation.</li>
+<p>This release includes many other improvements, including improvements to
+ the optimizers and code generators (improving the generated code) changes to
+ speed up the compiler in many ways (improving algorithms and fine tuning
+ code), and changes to reduce the code size of the compiler itself.</p>
+
+<p>More specific changes include:</p>
+<ul>
+<li>The llvm-test framework now supports SPEC2006.</li>
+<li>LLVM now includes a <a href="GetElementPtr.html">FAQ about the
+<tt>getelementptr</tt> instruction</a>.</li>
+<li>Bugpoint now supports a new "<tt>-find-bugs</tt>" mode. This mode makes
+ bugpoint permute pass sequences to try to expose bugs due to pass
+ sequencing.</li>
+<li>The JIT now supports lazily streaming code from multiple modules at a
+ time, implicitly linking the code as it goes.</li>
</ul>
</div>
-
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="changes">Significant Changes in LLVM 1.7</a>
+<a name="apichanges">Significant API Changes in LLVM 1.9</a>
</div>
<div class="doc_text">
+
+<p>Several significant API changes have been made. If you are maintaining
+out-of-tree code, please be aware that:</p>
+
<ul>
-<li>The LLVM intrinsics used to be overloaded based on type: for example,
- <a href="LangRef.html#int_ctpop"><tt>llvm.ctpop</tt></a> could work with any
- integer datatype. They are now separated into different intrinsics with
- suffixes to denote their argument type (e.g. <tt>llvm.ctpop.i32</tt>)). Old
- LLVM .ll and .bc files that use these intrinsics will continue to work with
- new LLVM versions (they are transparently upgraded by the parsers), but will
- cause a warning to be emitted.</li>
-<li>The <tt>llvm.readport</tt>, <tt>llvm.writeport</tt>, <tt>llvm.readio</tt>,
- and <tt>llvm.writeio</tt> intrinsics have been removed. The first two
- were ever only supported by the X86 backend, the last two were never
- correctly supported by any target, and none were accessible through the
- C front-end. Inline assembly support can now be used to
- implement these operations.</li>
-<li>The <tt>llvm-db</tt> tool had basic support for stepping through code, which
- used the JIT. This code has been removed, and DWARF emission support added
- instead. <tt>llvm-db</tt> still exists in CVS if someone wanted to write a
- <tt>ptrace</tt> backend for it.</li>
+<li>The ConstantSInt and ConstantUInt classes have been merged into the
+ ConstantInt class.</li>
+<li><p>As a step towards making LLVM's integer types signless, several new
+instructions have been added to LLVM. The <tt>Div</tt> instruction is now
+<tt>UDiv</tt>, <tt>SDiv</tt>, and <tt>FDiv</tt>. The <tt>Rem</tt> instruction
+is now <tt>URem</tt>, <tt>SRem</tt> and <tt>FRem</tt>. See the
+<a href="LangRef.html">Language Reference</a> for details on these new
+instructions.</p>
+<li><p><tt>ConstantBool::True</tt> and <tt>ConstantBool::False</tt> have been
+ renamed to <tt>ConstantBool::getTrue()</tt> and
+ <tt>ConstantBool::getFalse()</tt>.</p></li>
+<li>The 'analyze' tool has been merged into the 'opt' tool.</li>
+
</ul>
</div>
<ul>
<li>Intel and AMD machines running Red Hat Linux, Fedora Core and FreeBSD
(and probably other unix-like systems).</li>
+<li>Intel and AMD machines running on Win32 using MinGW libraries (native)</li>
<li>Sun UltraSPARC workstations running Solaris 8.</li>
<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
support is available for native builds with Visual C++).</li>
-<li>PowerPC and X86-based Mac OS X systems, running 10.2 and above.</li>
+<li>PowerPC and X86-based Mac OS X systems, running 10.2 and above in 32-bit and
+ 64-bit modes.</li>
<li>Alpha-based machines running Debian GNU/Linux.</li>
<li>Itanium-based machines running Linux and HP-UX.</li>
</ul>
be broken or unreliable, or are in early development. These components should
not be relied on, and bugs should not be filed against them, but they may be
useful to some people. In particular, if you would like to work on one of these
-components, please contact us on the llvmdev list.</p>
+components, please contact us on the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
<ul>
<li>The <tt>-cee</tt> pass is known to be buggy, and may be removed in in a
future release.</li>
<li>The IA64 code generator is experimental.</li>
+<li>The ARM code generator is experimental.</li>
<li>The Alpha JIT is experimental.</li>
<li>"<tt>-filetype=asm</tt>" (the default) is the only supported value for the
<tt>-filetype</tt> llc option.</li>
<!-- ======================================================================= -->
<div class="doc_subsection">
- <a name="build">Known problems with the Build System</a>
+ <a name="x86-be">Known problems with the X86 back-end</a>
</div>
<div class="doc_text">
<ul>
- <li>The <a href="http://llvm.org/PR656">configure script sometimes fails on Solaris/Sparc</a>. A work around is documented in <a href="http://llvm.org/PR656">PR656.</a></li>
+<li>The X86 backend does not yet support <a href="http://llvm.org/PR879">inline
+ assembly that uses the X86 floating point stack</a>. See the <a
+ href="http://llvm.org/PR879">bug</a> for details on workarounds on
+ Linux.</li>
</ul>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="ppc-be">Known problems with the PowerPC back-end</a>
+</div>
+
+<div class="doc_text">
+
+<ul>
+<li><a href="http://llvm.org/PR642">PowerPC backend does not correctly
+implement ordered FP comparisons</a>.</li>
+<li>The 64-bit PowerPC backend is not fully stable. If you desire PPC64 support,
+ please use mainline CVS LLVM, which has several important bug fixes.</li>
+</ul>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="sparc-be">Known problems with the SPARC back-end</a>
</div>
+<div class="doc_text">
+
+<ul>
+<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
+ support the 64-bit SPARC ABI (-m64).</li>
+</ul>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="c-be">Known problems with the C back-end</a>
+</div>
+
+<div class="doc_text">
+
+<ul>
+
+<li>The C back-end produces code that violates the ANSI C Type-Based Alias
+Analysis rules. As such, special options may be necessary to compile the code
+(for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
+problem probably cannot be fixed.</li>
+
+<li><a href="http://llvm.org/PR56">Zero arg vararg functions are not
+supported</a>. This should not affect LLVM produced by the C or C++
+frontends.</li>
+
+<li>The C backend does not correctly implement the <a
+href="LangRef.html#i_stacksave"><tt>llvm.stacksave</tt></a> or
+<a href="LangRef.html#i_stackrestore"><tt>llvm.stackrestore</tt></a>
+intrinsics. This means that some code compiled by it can run out of stack
+space if they depend on these (e.g. C99 varargs).</li>
+
+<li><a href="http://llvm.org/PR802">The C backend does not support inline
+ assembly code</a>.</li>
+</ul>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="alpha-be">Known problems with the Alpha back-end</a>
+</div>
+
+<div class="doc_text">
+
+<ul>
+
+<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
+appropriate nops inserted to ensure restartability.</li>
+
+</ul>
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="ia64-be">Known problems with the IA64 back-end</a>
+</div>
+
+<div class="doc_text">
+
+<ul>
+
+<li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are
+made where the argument is not 16-byte aligned, as required on IA64. (Strictly
+speaking this is not a bug in the IA64 back-end; it will also be encountered
+when building C++ programs using the C back-end.)</li>
+
+<li>The C++ front-end does not use <a href="http://llvm.org/PR406">IA64
+ABI compliant layout of v-tables</a>. In particular, it just stores function
+pointers instead of function descriptors in the vtable. This bug prevents
+mixing C++ code compiled with LLVM with C++ objects compiled by other C++
+compilers.</li>
+
+<li>There are a few ABI violations which will lead to problems when mixing LLVM
+output with code built with other compilers, particularly for floating-point
+programs.</li>
+
+<li>Defining vararg functions is not supported (but calling them is ok).</li>
+
+</ul>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="arm-be">Known problems with the ARM back-end</a>
+</div>
+
+<div class="doc_text">
+
+<ul>
+<li>The ARM backend is currently in early development stages, it is not
+ready for production use.</li>
+</ul>
+
+</div>
<!-- ======================================================================= -->
<div class="doc_subsection">
<div class="doc_text">
<p>
-llvm-gcc3 has many significant problems that are fixed by llvm-gcc4. See
- those blocked on the <a href="http://llvm.org/PR498">llvm-gcc4 meta bug</a>.
-Two signicant ones include:</p>
-<ul>
-<li>With llvm-gcc3,
- C99 variable sized arrays do not release stack memory when they go out of
- scope. Thus, the following program may run out of stack space:
-<pre>
- for (i = 0; i != 1000000; ++i) {
- int X[n];
- foo(X);
- }
-</pre></li>
-
-<li>With llvm-gcc3, Initialization of global union variables can only be done <a
-href="http://llvm.org/PR162">with the largest union member</a>.</li>
+<p>llvm-gcc4 is far more stable and produces better code than llvm-gcc3, but
+does not currently support <a href="http://llvm.org/PR869">Link-Time
+Optimization</a> or <a href="http://llvm.org/PR870">C++ Exception Handling</a>,
+which llvm-gcc3 does.</p>
+
+<p>llvm-gcc4 does not support the <a href="http://llvm.org/PR947">GCC indirect
+goto extension</a>, but llvm-gcc3 does.</p>
-</ul>
</div>
<!-- _______________________________________________________________________ -->
support for floating point data types of any size other than 32 and 64
bits.</li>
-<li>The following Unix system functionality has not been tested and may not
-work:
- <ol>
- <li><tt>sigsetjmp</tt>, <tt>siglongjmp</tt> - These are not turned into the
- appropriate <tt>invoke</tt>/<tt>unwind</tt> instructions. Note that
- <tt>setjmp</tt> and <tt>longjmp</tt> <em>are</em> compiled correctly.
- <li><tt>getcontext</tt>, <tt>setcontext</tt>, <tt>makecontext</tt>
- - These functions have not been tested.
- </ol></li>
-
<li>Although many GCC extensions are supported, some are not. In particular,
the following extensions are known to <b>not be</b> supported:
<ol>
<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block.</li>
<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>
<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.</li>
- <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>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands.</li>
- <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>
- <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>
- <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>
- <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>
<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread_002dLocal.html">Thread-Local</a>: Per-thread variables.</li>
<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pragmas.html#Pragmas">Pragmas</a>: Pragmas accepted by GCC.</li>
</ol>
Declaring that functions have no side effects or that they can never
return.<br>
- <b>Supported:</b> <tt>format</tt>, <tt>format_arg</tt>, <tt>non_null</tt>,
- <tt>noreturn</tt>, <tt>constructor</tt>, <tt>destructor</tt>,
- <tt>unused</tt>, <tt>used</tt>,
- <tt>deprecated</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
+ <b>Supported:</b> <tt>constructor</tt>, <tt>destructor</tt>,
+ <tt>deprecated</tt>, <tt>fastcall</tt>, <tt>format</tt>,
+ <tt>format_arg</tt>, <tt>non_null</tt>, <tt>noreturn</tt>,
+ <tt>section</tt>, <tt>stdcall</tt>, <tt>unused</tt>, <tt>used</tt>,
+ <tt>visibility</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
<b>Ignored:</b> <tt>noinline</tt>,
<tt>always_inline</tt>, <tt>pure</tt>, <tt>const</tt>, <tt>nothrow</tt>,
<tt>malloc</tt>, <tt>no_instrument_function</tt>, <tt>cdecl</tt><br>
- <b>Unsupported:</b> <tt>section</tt>, <tt>alias</tt>,
- <tt>visibility</tt>, <tt>regparm</tt>, <tt>stdcall</tt>,
- <tt>fastcall</tt>, all other target specific attributes</li>
+ <b>Unsupported:</b> <tt>alias</tt>, <tt>regparm</tt>, all other target specific
+ attributes</li>
<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
Specifying attributes of variables.<br>
<b>Supported:</b> <tt>cleanup</tt>, <tt>common</tt>, <tt>nocommon</tt>,
- <tt>deprecated</tt>, <tt>transparent_union</tt>,
- <tt>unused</tt>, <tt>used</tt>, <tt>weak</tt><br>
+ <tt>deprecated</tt>, <tt>dllimport</tt>, <tt>dllexport</tt>,
+ <tt>section</tt>, <tt>transparent_union</tt>, <tt>unused</tt>,
+ <tt>used</tt>, <tt>weak</tt><br>
<b>Unsupported:</b> <tt>aligned</tt>, <tt>mode</tt>, <tt>packed</tt>,
- <tt>section</tt>, <tt>shared</tt>, <tt>tls_model</tt>,
- <tt>vector_size</tt>, <tt>dllimport</tt>,
- <tt>dllexport</tt>, all target specific attributes.</li>
+ <tt>shared</tt>, <tt>tls_model</tt>,
+ <tt>vector_size</tt>, all target specific attributes.
+ </li>
<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html#Type%20Attributes">Type Attributes</a>: Specifying attributes of types.<br>
<b>Supported:</b> <tt>transparent_union</tt>, <tt>unused</tt>,
<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.</li>
<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>
<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.</li>
+ <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>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands.</li>
+ <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>
+ <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>
+ <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>
+ <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>
<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>
<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>
<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Initializers.html#Initializers">Initializers</a>: Non-constant initializers.</li>
</div>
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">Bugs</div>
-
-<div class="doc_text">
-
-<ul>
-<li>The C++ front-end inherits all problems afflicting the <a href="#c-fe">C
- front-end</a>.</li>
-
-</ul>
-
-</div>
-
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
Notes
</div>
<div class="doc_text">
-
<ul>
+<li>llvm-gcc4 does not support C++ exception handling at all yet.</li>
<li>Destructors for local objects are not always run when a <tt>longjmp</tt> is
performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
representation issues. Because we use this API, code generated by the LLVM
compilers should be binary compatible with machine code generated by other
Itanium ABI C++ compilers (such as G++, the Intel and HP compilers, etc).
- <i>However</i>, the exception handling mechanism used by LLVM is very
+ <i>However</i>, the exception handling mechanism used by llvm-gcc3 is very
different from the model used in the Itanium ABI, so <b>exceptions will not
interact correctly</b>. </li>
</div>
-<!-- ======================================================================= -->
-<div class="doc_subsection">
- <a name="c-be">Known problems with the C back-end</a>
-</div>
-
-<div class="doc_text">
-
-<ul>
-
-<li>The C back-end produces code that violates the ANSI C Type-Based Alias
-Analysis rules. As such, special options may be necessary to compile the code
-(for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
-problem probably cannot be fixed.</li>
-
-<li><a href="http://llvm.org/PR56">Zero arg vararg functions are not
-supported</a>. This should not affect LLVM produced by the C or C++
-frontends.</li>
-
-<li>The C backend does not correctly implement the <a
-href="LangRef.html#i_stacksave"><tt>llvm.stacksave</tt></a> or
-<a href="LangRef.html#i_stackrestore"><tt>llvm.stackrestore</tt></a>
-intrinsics. This means that some code compiled by it can run out of stack
-space if they depend on these (e.g. C99 varargs).</li>
-
-</ul>
-
-</div>
-
-<!-- ======================================================================= -->
-<div class="doc_subsection">
- <a name="x86-be">Known problems with the X86 back-end</a>
-</div>
-
-<div class="doc_text">
-<ul>
-<li><a href="http://llvm.org/PR736">Indirect calls crash JIT on
-Darwin/x86</a>.</li>
-</ul>
-
-</div>
-
-<!-- ======================================================================= -->
-<div class="doc_subsection">
- <a name="ppc-be">Known problems with the PowerPC back-end</a>
-</div>
-
-<div class="doc_text">
-
-<ul>
-<li><a href="http://llvm.org/PR642">PowerPC backend does not correctly
-implement ordered FP comparisons</a>.</li>
-</ul>
-
-</div>
-
-<!-- ======================================================================= -->
-<div class="doc_subsection">
- <a name="alpha-be">Known problems with the Alpha back-end</a>
-</div>
-
-<div class="doc_text">
-
-<ul>
-
-<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
-appropriate nops inserted to ensure restartability.</li>
-
-</ul>
-
-</div>
-
-<!-- ======================================================================= -->
-<div class="doc_subsection">
- <a name="ia64-be">Known problems with the IA64 back-end</a>
-</div>
-
-<div class="doc_text">
-
-<ul>
-
-<li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are
-made where the argument is not 16-byte aligned, as required on IA64. (Strictly
-speaking this is not a bug in the IA64 back-end; it will also be encountered
-when building C++ programs using the C back-end.)</li>
-
-<li>The C++ front-end does not use <a href="http://llvm.org/PR406">IA64
-ABI compliant layout of v-tables</a>. In particular, it just stores function
-pointers instead of function descriptors in the vtable. This bug prevents
-mixing C++ code compiled with LLVM with C++ objects compiled by other C++
-compilers.</li>
-
-<li>There are a few ABI violations which will lead to problems when mixing LLVM
-output with code built with other compilers, particularly for floating-point
-programs.</li>
-
-<li>Defining vararg functions is not supported (but calling them is ok).</li>
-
-</ul>
-
-</div>
-
-<!-- ======================================================================= -->
-<div class="doc_subsection">
- <a name="sparc-be">Known problems with the SPARC back-end</a>
-</div>
-
-<div class="doc_text">
-
-<ul>
-<li>None yet</li>
-</ul>
-
-</div>
-
-
-<!-- ======================================================================= -->
-<div class="doc_subsection">
- <a name="sparcv9-be">Known problems with the SparcV9 back-end</a>
-</div>
-
-<div class="doc_text">
-
-<ul>
-<li><a href="http://llvm.org/PR60">[sparcv9] SparcV9 backend miscompiles
-several programs in the LLVM test suite</a></li>
-<li>The SparcV9 backend is slated to be removed before the LLVM 1.8
- release.</li>
-</ul>
-
-</div>
<!-- *********************************************************************** -->
<div class="doc_section">
projects / oota-llvm.git / blobdiff