rewrite the known problems section. Including a short list of individual bugs per target isn't particularly useful. Link to the target features matrix.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145193 91177308-0d34-0410-b5e6-96231b3b80d8
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Chris Lattner 2011-11-27 19:38:20 +00:00
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@ -1330,144 +1330,30 @@ compiler and provides better integration with the platform ABI as a result.</p>
<div>
<p>This section contains significant known problems with the LLVM system, listed
by component. If you run into a problem, please check
the <a href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
there isn't already one.</p>
<!-- ======================================================================= -->
<h3>
<a name="experimental">Experimental features included with this release</a>
</h3>
<div>
<p>The following components of this LLVM release are either untested, known to
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 <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev
list</a>.</p>
<p>LLVM is generally a production quality compiler, and is used by a broad range
of applications and shipping in many products. That said, not every
subsystem is as mature as the aggregate, particularly the more obscure
targets. If you run into a problem, please check the <a
href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
there isn't already one or ask on the <a
href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev
list</a>.</p>
<p>Known problem areas include:</p>
<ul>
<li>The Alpha, Blackfin, CellSPU, MicroBlaze, MSP430, MIPS, PTX, SystemZ and
XCore backends are experimental.</li>
<li>The Alpha, Blackfin, CellSPU, MSP430, PTX, SystemZ and
XCore backends are experimental, and several of these have already been
removed from mainline.</li>
<li><tt>llc</tt> "<tt>-filetype=obj</tt>" is experimental on all targets other
than darwin and ELF X86 systems.</li>
</ul>
</div>
<!-- ======================================================================= -->
<h3>
<a name="x86-be">Known problems with the X86 back-end</a>
</h3>
<div>
<ul>
<li>The X86-64 backend <a href="http://llvm.org/PR1740">does not yet support
the <tt>va_arg</tt> LLVM IR instruction</a>. Currently, front-ends support
variadic argument constructs on X86-64 by lowering them manually.</li>
</ul>
</div>
<!-- ======================================================================= -->
<h3>
<a name="ppc-be">Known problems with the PowerPC back-end</a>
</h3>
<div>
<ul>
<li>The PPC32/ELF support lacks PIC support.</li>
</ul>
</div>
<!-- ======================================================================= -->
<h3>
<a name="arm-be">Known problems with the ARM back-end</a>
</h3>
<div>
<ul>
<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
processors, thumb programs can crash or produce wrong results
(<a href="http://llvm.org/PR1388">PR1388</a>).</li>
<li>Compilation for ARM Linux OABI (old ABI) is supported but not fully
tested.</li>
</ul>
</div>
<!-- ======================================================================= -->
<h3>
<a name="sparc-be">Known problems with the SPARC back-end</a>
</h3>
<div>
<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>
<!-- ======================================================================= -->
<h3>
<a name="mips-be">Known problems with the MIPS back-end</a>
</h3>
<div>
<ul>
<li>64-bit MIPS targets are not supported yet.</li>
</ul>
</div>
<!-- ======================================================================= -->
<h3>
<a name="alpha-be">Known problems with the Alpha back-end</a>
</h3>
<div>
<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>
<!-- ======================================================================= -->
<h3>
<a name="c-be">Known problems with the C back-end</a>
</h3>
<div>
<p>The C backend has numerous problems and is not being actively maintained.
Depending on it for anything serious is not advised.</p>
<ul>
<li><a href="http://llvm.org/PR802">The C backend has only basic support for
inline assembly code</a>.</li>
<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
C++ programs</a>, preventing intermixing between C++ compiled by the CBE
and C++ code compiled with <tt>llc</tt> or native compilers.</li>
<li>The C backend does not support all exception handling constructs.</li>
<li>The C backend does not support arbitrary precision integers.</li>
<li>The integrated assembler, disassembler, and JIT is not supported by
several targets. If an integrated assembler is not supported, then a
system assembler is required. For more details, see the <a
href="CodeGenerator.html#targetfeatures">Target Features Matrix</a>.
</li>
<li>The C backend has numerous problems and is not being actively maintained.
Depending on it for anything serious is not advised.</li>
</ul>
</div>