<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>Le 23 nov. 2011 à 09:18, Ruben Van Boxem a écrit :</div><br class="Apple-interchange-newline"><blockquote type="cite">2011/11/23 Chandler Carruth <span dir="ltr"><<a href="mailto:chandlerc@google.com" target="_blank">chandlerc@google.com</a>></span><br><div class="gmail_quote"><div class="gmail_quote"><div><div class="h5"><blockquote class="gmail_quote" style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0.8ex; border-left-width: 1px; border-left-color: rgb(204, 204, 204); border-left-style: solid; padding-left: 1ex; position: static; z-index: auto; ">
It has come up when reviewing Kostya's patch to add the necessary support fort linking in the Address Sanitizer runtime library that we need a proper scheme and plan for deploying runtime libraries along with Clang.<div>
<br></div><div>I've CC'ed llvmdev on this for compiler-rt developers' input.</div><div><br></div><div>The key issues I see when locating runtime libraries are the following:</div><div><br></div><div>- These libraries should be shipped with Clang, not installed separately on the system.</div>
<div>- They are likely to be somewhat tied to specific versions of Clang/LLVM.</div><div>- To support cross-compiling, we should be able to install multiple copies of these libraries in a single Clang installation, and use the appropriate one when targeting a particular platform.</div>
<div>- The above cross-compiling concern extends to ABI compatibility -- many of the ABIs are already fixed in this space.</div><div>- These are different from builtin header files which can use the preprocessor to internally differentiate their contents based on the target platform.</div>
<div><br></div><div>My proposed solution:</div><div><br></div><div>- Base the path on the shared "resource directory" concept which already exists in Clang.</div><div> - Builtin header files are at <ResourceDir>/include already.</div>
<div>- Append a "base" triple directory name.</div><div>- Append a "lib" directory name for runtime libraries</div><div>- Place the runtime libraries as "libcompiler_rt_<sublib>.a" for each sub-library component "<sublib>".</div>
<div><br></div><div>Example for "x/bin/clang" installation:</div><div> x/bin/../lib/clang/3.1/x86_64-linux-gnu/lib/libcompiler_rt_asan.a</div><div><br></div><div>What is a "base" triple? It is the simplest form we can reduce a triple to while guaranteeing compatibility. The concept is best explained by an example. All of the following triples reduce to the base triple of "x86_64-linux-gnu":</div>
<div> x86_64-linux-gnu</div><div> x86_64-pc-linux-gnu</div><div> x86_64-unknown-linux-gnu</div><div> x86_64-redhat-linux</div><div> x86_64-redhat-linux6E</div><div> ...</div><div><br></div><div>A different ABI could be expressed much like ARM's is with the last element: "*-gnueabi". This would *not* reduce to the triple ending in '-gnu'. Due to the adhoc and poorly spec'ed nature of existing triples, this will largely be a fixed mapping much like already exists in the Clang driver, but consolidated into LLVM's core triple logic.</div>
</blockquote></div></div><div><br>This does kind of push the GNU triple language on LLVM/Clang internally, although the jury was still out on the true specification for cross-compiling platform names. Although internal, it really will keep spreading like a "disease" to more exposed parts of Clang.<br></div></div></div></blockquote><div><br></div>And it does not play well with universal binaries, which are actually used for darwin compiler_rt libraries. Not that I think this is a major issue, but it probably should be considered too.<br><br></div><div>
<span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div>-- Jean-Daniel</div><div><br></div><div><br></div></span><br class="Apple-interchange-newline">
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