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<p class="MsoNormal"><span style="color:#1F497D">If there are no further comments to this, I think it makes sense to setup the review and continue with detailed discussions via cfe-commits.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">I plan to address the PCH size issue in general as a separate thread.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Cheers,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Anastasia<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> cfe-dev [mailto:cfe-dev-bounces@lists.llvm.org]
<b>On Behalf Of </b>Anastasia Stulova via cfe-dev<br>
<b>Sent:</b> 10 March 2016 18:56<br>
<b>To:</b> Liu, Yaxun (Sam); 'cfe-dev@lists.llvm.org' (cfe-dev@lists.llvm.org)<br>
<b>Cc:</b> Stellard, Thomas; nd; Bader, Alexey (alexey.bader@intel.com); Sumner, Brian; Pan, Xiuli<br>
<b>Subject:</b> Re: [cfe-dev] [OpenCL] upstreaming khronos OpenCL header files<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="color:#1F497D">> but it seems PCHs have even larger size by a factor of 10.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">To remove any confusion in my previous email, it’s actually factor of 2 (not 10!).<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> cfe-dev [<a href="mailto:cfe-dev-bounces@lists.llvm.org">mailto:cfe-dev-bounces@lists.llvm.org</a>]
<b>On Behalf Of </b>Anastasia Stulova via cfe-dev<br>
<b>Sent:</b> 10 March 2016 18:16<br>
<b>To:</b> Liu, Yaxun (Sam); <a href="mailto:cfe-dev@lists.llvm.org">cfe-dev@lists.llvm.org</a><br>
<b>Cc:</b> nd; Bader, Alexey (<a href="mailto:alexey.bader@intel.com">alexey.bader@intel.com</a>); Stellard, Thomas; Sumner, Brian; Pan, Xiuli<br>
<b>Subject:</b> Re: [cfe-dev] [OpenCL] upstreaming khronos OpenCL header files<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="color:#1F497D">I see a benefit for the OpenCL users of open source Clang to be able to have the standard includes automatically or at least to have them in the same place as the compiler.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">I am not sure if we might have some issue with their size though.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Each header is approximately 1MB large. It might be an issue not just for space but also parsing time. Using PCH would help to reduce compilation time but it seems PCHs have even larger size by a factor of 10.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">For example:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"> opencl-12.h - 916K <o:p>
</o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"> opencl-12.h.pch - 1.9M<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">It is a bit surprising though since PCHs are stored using compressed bitstream as LLVM’s bitcode file format according to the documentation page. Has anyone looked at it before? Size is generally a problem for
embedded devices.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Anastasia<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> Liu, Yaxun (Sam) [<a href="mailto:Yaxun.Liu@amd.com">mailto:Yaxun.Liu@amd.com</a>]
<br>
<b>Sent:</b> 09 March 2016 19:29<br>
<b>To:</b> <a href="mailto:cfe-dev@lists.llvm.org">cfe-dev@lists.llvm.org</a><br>
<b>Cc:</b> Bader, Alexey (<a href="mailto:alexey.bader@intel.com">alexey.bader@intel.com</a>); Sumner, Brian; Stellard, Thomas; Anastasia Stulova; Pan, Xiuli<br>
<b>Subject:</b> RFC: [OpenCL] upstreaming khronos OpenCL header files<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span lang="EN-US">Hi,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">OpenCL predefines many overloaded builtin functions (‘builtin’ in the sense of OpenCL spec) which are not defined in Clang. As such, to compile OpenCL kernels which call OpenCL ‘builtin’ functions, a header file declaring
these functions is needed.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">The khronos OpenCL header files can be found at these links:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoPlainText"><a href="https://github.com/KhronosGroup/SPIR/blob/spirv-1.0/lib/Headers/opencl-20.h"><span lang="EN-US">https://github.com/KhronosGroup/SPIR/blob/spirv-1.0/lib/Headers/opencl-20.h</span></a><span lang="EN-US"><o:p></o:p></span></p>
<p class="MsoPlainText"><a href="https://github.com/KhronosGroup/SPIR/blob/spirv-1.0/lib/Headers/opencl-12.h"><span lang="EN-US">https://github.com/KhronosGroup/SPIR/blob/spirv-1.0/lib/Headers/opencl-12.h</span></a><span lang="EN-US"><o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">I am wondering if upstreaming these header files to Clang trunk at clang/lib/Headers would save the OpenCL users the trouble of downloading these header files from different places.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Also with these header files upstreamed, we could make them implicitly included so that users do not need to include them explicitly.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Your feedback is welcome.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Thanks.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Sam<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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