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<p class="MsoNormal"><a name="_MailEndCompose"><span lang="EN-US" style="color:#1F497D;mso-fareast-language:EN-US">Hi Sam,<o:p></o:p></span></a></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D;mso-fareast-language:EN-US">I want to clarify the use case.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D;mso-fareast-language:EN-US">The intension is to allow library developer redefining OpenCL images types in a library written in OpenCL C and prefix starting with double underscore is supposed to protect
the library image types definitions from redefinition by user. <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D;mso-fareast-language:EN-US">The change you are proposing is to rename image opaque types in LLVM IR, without making them concrete.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D;mso-fareast-language:EN-US">Am I getting it right?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D;mso-fareast-language:EN-US">Wouldn’t types defined by library developer prefixed with ‘struct.’? Shouldn’t clang create opaque types with ‘struct.__opencl_’ prefix instead to match the type names
defined by library developer?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D">Thanks,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D">Alexey<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><a name="_____replyseparator"></a><b><span lang="EN-US">From:</span></b><span lang="EN-US"> Anastasia Stulova [mailto:Anastasia.Stulova@arm.com]
<br>
<b>Sent:</b> Monday, July 25, 2016 6:41 PM<br>
<b>To:</b> Liu, Yaxun (Sam) <Yaxun.Liu@amd.com>; cfe-dev (cfe-dev@lists.llvm.org) <cfe-dev@lists.llvm.org><br>
<b>Cc:</b> Sumner, Brian <Brian.Sumner@amd.com>; Bader, Alexey <alexey.bader@intel.com>; Pan, Xiuli <xiuli.pan@intel.com>; nd <nd@arm.com><br>
<b>Subject:</b> RE: [RFC][OpenCL] Rename OpenCL opaque types in LLVM IR from opencl.* to __opencl_*<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span lang="EN-GB" style="color:#1F497D">Sounds good to me!<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="color:#1F497D">Thanks,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="color:#1F497D">Anastasia<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" 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> 20 July 2016 18:49<br>
<b>To:</b> cfe-dev (<a href="mailto:cfe-dev@lists.llvm.org">cfe-dev@lists.llvm.org</a>)<br>
<b>Cc:</b> Anastasia Stulova; Sumner, Brian; Bader, Alexey (<a href="mailto:alexey.bader@intel.com">alexey.bader@intel.com</a>); Pan, Xiuli<br>
<b>Subject:</b> [RFC][OpenCL] Rename OpenCL opaque types in LLVM IR from opencl.* to __opencl_*<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Currently OpenCL opaque types have name opencl.* in LLVM IR, which causes difficulty for library developers who need to implement the concrete types corresponding to the opaque types.<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">For example, read_only image2d_t type is translated to opencl.image2d_ro_t addrspace(1)* in LLVM IR. Ideally, a library developer would implement a concreate struct type with name opencl.image2d_ro_t and access its members.
However, due to the ‘.’, ‘opencl.image2d_ro_t’ is not a valid identifier in OpenCL C language, library developers cannot use it as the name of the concrete struct type for image2d_t. Bitcasts have to be introduced, which causes extra efforts in backends.<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">Due to this reason, we would like to propose renaming OpenCL opaque types in LLVM IR from opencl.* to __opencl_*.<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">This change will make the IR deviate from SPIR spec. However, considering there is simple rule to map this new name to SPIR defined name, and LLVM IR currently generated by Clang has already been deviated from SPIR spec,
a SPIR consumer should be able to accommodate this change if it is able to accommodate existing deviations.<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 feedbacks are welcome. 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>
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