<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>On Mar 21, 2013, at 7:24 PM, Chandler Carruth <<a href="mailto:chandlerc@google.com">chandlerc@google.com</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div dir="ltr">FYI, I reverted the patch in r177695 to fix our builds. We check that layering violations don't get any worse in our build system.<div><br></div><div>Fundamentally, the existing layering problem is "worked around" but there being no implementation. As long as thats true, all the Support library is providing is a text header file. As long as it is only included into source files that are part of a library which will eventually get linked with the core library, the AsmParser library, and the BitcodeReader library, all is well. Including it into a source file in Support makes the layering violation actively worse.</div>
<div><br></div><div style="">I think the correct solution is to do one of two things:</div><div style=""><br></div><div style="">1) Create a new library which depends on both AsmParser and BitcodeReader and which can be used by opt and friends. Put IRReader here.</div>
<div style="">2) Fold AsmParser into the IR library (where AsmWriter already lives). Put IRReader into the BitcodeReader library.</div><div style=""><br></div><div style="">I thought about a third option: put both AsmParser and IRReader into the BitcodeReader library. But increasingly that seems like a really gross layering.</div></div></blockquote><div><br></div><div>I like option #2, but some people might not want to link in the largish parser lib.</div><div><br></div><div>Seems like the IR library should provide a text header IRReader.h. Anyone calling it should also link AsmParser and BitcodeReader. I don't think we need IRReader.cpp, but if we did it would be implemented in /IR and linked in LLVMCore.</div><div><br></div><div>-Andy</div><div><br></div><blockquote type="cite"><div class="gmail_extra"><div class="gmail_quote">On Wed, Mar 20, 2013 at 9:59 PM, Chandler Carruth <span dir="ltr"><<a href="mailto:chandlerc@google.com" target="_blank">chandlerc@google.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="im"><br><div class="gmail_quote">On Wed, Mar 20, 2013 at 8:23 PM, Andrew Trick <span dir="ltr"><<a href="mailto:atrick@apple.com" target="_blank">atrick@apple.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">I don't pretend to understand the layering rules. But how can someone use IRReader without linking LLVMCore? I'm not even sure why IRReader is in Support given that it needs a context.</blockquote>
</div><br></div>IRReader is the layering violation. We should fix that, and then this becomes a non-problem.</div><div class="gmail_extra"><br></div><div class="gmail_extra">And yea, I think putting the flag in the context makes a lot of sense.</div>
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