<div dir="ltr">It's complaining about the declaration. As far as I can tell, your declaration does appear to have external linkage, so I am not sure what is triggering this issue.<div><br></div><div>What version of clang? What linker?</div><div><br></div><div>Teresa</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Sep 12, 2017 at 2:39 AM, Samuel Williams via cfe-dev <span dir="ltr"><<a href="mailto:cfe-dev@lists.llvm.org" target="_blank">cfe-dev@lists.llvm.org</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"><p style="margin:0px 0px 1em;padding:0px;border:0px;font-variant-numeric:inherit;font-stretch:inherit;font-size:15px;line-height:inherit;font-family:Arial,"Helvetica Neue",Helvetica,sans-serif;vertical-align:baseline;clear:both;color:rgb(36,39,41)">I'm trying to build <code style="margin:0px;padding:1px 5px;border:0px;font-style:inherit;font-variant:inherit;font-weight:inherit;font-stretch:inherit;font-size:13px;line-height:inherit;font-family:Consolas,Menlo,Monaco,"Lucida Console","Liberation Mono","DejaVu Sans Mono","Bitstream Vera Sans Mono","Courier New",monospace,sans-serif;vertical-align:baseline;background-color:rgb(239,240,241);white-space:pre-wrap">coro.c</code> using Clang+LTO.</p><p style="margin:0px 0px 1em;padding:0px;border:0px;font-variant-numeric:inherit;font-stretch:inherit;font-size:15px;line-height:inherit;font-family:Arial,"Helvetica Neue",Helvetica,sans-serif;vertical-align:baseline;clear:both;color:rgb(36,39,41)">When I link together the final binary, I get the following error:</p><pre style="margin-top:0px;margin-bottom:1em;padding:5px;border:0px;font-variant-numeric:inherit;font-stretch:inherit;font-size:13px;line-height:inherit;font-family:Consolas,Menlo,Monaco,"Lucida Console","Liberation Mono","DejaVu Sans Mono","Bitstream Vera Sans Mono","Courier New",monospace,sans-serif;vertical-align:baseline;width:auto;max-height:600px;overflow:auto;background-color:rgb(239,240,241);word-wrap:normal;color:rgb(36,39,41)"><code style="margin:0px;padding:0px;border:0px;font-style:inherit;font-variant:inherit;font-weight:inherit;font-stretch:inherit;line-height:inherit;font-family:Consolas,Menlo,Monaco,"Lucida Console","Liberation Mono","DejaVu Sans Mono","Bitstream Vera Sans Mono","Courier New",monospace,sans-serif;vertical-align:baseline;white-space:inherit">Global is external, but doesn't have external or weak linkage!
void ()* @coro_transfer
</code></pre><p style="margin:0px 0px 1em;padding:0px;border:0px;font-variant-numeric:inherit;font-stretch:inherit;font-size:15px;line-height:inherit;font-family:Arial,"Helvetica Neue",Helvetica,sans-serif;vertical-align:baseline;clear:both;color:rgb(36,39,41)">The symbol is defined in <code style="margin:0px;padding:1px 5px;border:0px;font-style:inherit;font-variant:inherit;font-weight:inherit;font-stretch:inherit;font-size:13px;line-height:inherit;font-family:Consolas,Menlo,Monaco,"Lucida Console","Liberation Mono","DejaVu Sans Mono","Bitstream Vera Sans Mono","Courier New",monospace,sans-serif;vertical-align:baseline;background-color:rgb(239,240,241);white-space:pre-wrap">coro.h</code> as:</p><pre style="margin-top:0px;margin-bottom:1em;padding:5px;border:0px;font-variant-numeric:inherit;font-stretch:inherit;font-size:13px;line-height:inherit;font-family:Consolas,Menlo,Monaco,"Lucida Console","Liberation Mono","DejaVu Sans Mono","Bitstream Vera Sans Mono","Courier New",monospace,sans-serif;vertical-align:baseline;width:auto;max-height:600px;overflow:auto;background-color:rgb(239,240,241);word-wrap:normal;color:rgb(36,39,41)"><code style="margin:0px;padding:0px;border:0px;font-style:inherit;font-variant:inherit;font-weight:inherit;font-stretch:inherit;line-height:inherit;font-family:Consolas,Menlo,Monaco,"Lucida Console","Liberation Mono","DejaVu Sans Mono","Bitstream Vera Sans Mono","Courier New",monospace,sans-serif;vertical-align:baseline;white-space:inherit">#if __i386__ || __x86_64__
extern void __attribute__ ((__noinline__, __regparm__(2)))
#else
extern void __attribute__ ((__noinline__))
#endif
coro_transfer (coro_context *prev, coro_context *next);
</code></pre><p style="margin:0px 0px 1em;padding:0px;border:0px;font-variant-numeric:inherit;font-stretch:inherit;font-size:15px;line-height:inherit;font-family:Arial,"Helvetica Neue",Helvetica,sans-serif;vertical-align:baseline;clear:both;color:rgb(36,39,41)">and in <code style="margin:0px;padding:1px 5px;border:0px;font-style:inherit;font-variant:inherit;font-weight:inherit;font-stretch:inherit;font-size:13px;line-height:inherit;font-family:Consolas,Menlo,Monaco,"Lucida Console","Liberation Mono","DejaVu Sans Mono","Bitstream Vera Sans Mono","Courier New",monospace,sans-serif;vertical-align:baseline;background-color:rgb(239,240,241);white-space:pre-wrap">coro.c</code> as:</p><pre style="margin-top:0px;margin-bottom:1em;padding:5px;border:0px;font-variant-numeric:inherit;font-stretch:inherit;font-size:13px;line-height:inherit;font-family:Consolas,Menlo,Monaco,"Lucida Console","Liberation Mono","DejaVu Sans Mono","Bitstream Vera Sans Mono","Courier New",monospace,sans-serif;vertical-align:baseline;width:auto;max-height:600px;overflow:auto;background-color:rgb(239,240,241);word-wrap:normal;color:rgb(36,39,41)"><code style="margin:0px;padding:0px;border:0px;font-style:inherit;font-variant:inherit;font-weight:inherit;font-stretch:inherit;line-height:inherit;font-family:Consolas,Menlo,Monaco,"Lucida Console","Liberation Mono","DejaVu Sans Mono","Bitstream Vera Sans Mono","Courier New",monospace,sans-serif;vertical-align:baseline;white-space:inherit"> asm (
"\t.text\n"
#if _WIN32 || __CYGWIN__ || __MACH__
"\t.globl _coro_transfer\n"
"_coro_transfer:\n"
#else
"\t.globl coro_transfer\n"
"coro_transfer:\n"
#endif
</code></pre><p style="margin:0px 0px 1em;padding:0px;border:0px;font-variant-numeric:inherit;font-stretch:inherit;font-size:15px;line-height:inherit;font-family:Arial,"Helvetica Neue",Helvetica,sans-serif;vertical-align:baseline;clear:both;color:rgb(36,39,41)">It seems to me that it does have (or should) have global linkage. Is this a bug with LTO, or is there something wrong with the assembly definition?</p><p style="margin:0px 0px 1em;padding:0px;border:0px;font-variant-numeric:inherit;font-stretch:inherit;font-size:15px;line-height:inherit;font-family:Arial,"Helvetica Neue",Helvetica,sans-serif;vertical-align:baseline;clear:both;color:rgb(36,39,41)">I checked with nm and noticed the symbol was first undefined and then defined. I guess that's because of the declaration in the header but it's not technically a C function in the implementation.</p><pre style="margin-top:0px;margin-bottom:1em;padding:5px;border:0px;font-variant-numeric:inherit;font-stretch:inherit;line-height:inherit;vertical-align:baseline;width:auto;max-height:600px;overflow:auto;background-color:rgb(239,240,241);word-wrap:normal"><font color="#242729" face="Consolas, Menlo, Monaco, Lucida Console, Liberation Mono, DejaVu Sans Mono, Bitstream Vera Sans Mono, Courier New, monospace, sans-serif"><span style="font-size:13px">coro.c.o:
U abort
00000000 T coro_create
00000000 T coro_stack_alloc
00000000 T coro_stack_free
U coro_transfer
00000000 T coro_transfer
U mmap
U mprotect
U munmap
U sysconf</span></font><span style="color:rgb(36,39,41);font-family:Consolas,Menlo,Monaco,"Lucida Console","Liberation Mono","DejaVu Sans Mono","Bitstream Vera Sans Mono","Courier New",monospace,sans-serif;font-size:13px">
</span></pre><div>Could this be causing the problem?</div><div><br></div><div>Thanks for any ideas or suggestions.</div><div><br></div><div>Kind regards,</div><div>Samuel</div></div>
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<br></blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature" data-smartmail="gmail_signature"><span style="font-family:Times;font-size:medium"><table cellspacing="0" cellpadding="0"><tbody><tr style="color:rgb(85,85,85);font-family:sans-serif;font-size:small"><td nowrap style="border-top-style:solid;border-top-color:rgb(213,15,37);border-top-width:2px">Teresa Johnson |</td><td nowrap style="border-top-style:solid;border-top-color:rgb(51,105,232);border-top-width:2px"> Software Engineer |</td><td nowrap style="border-top-style:solid;border-top-color:rgb(0,153,57);border-top-width:2px"> <a href="mailto:tejohnson@google.com" target="_blank">tejohnson@google.com</a> |</td><td nowrap style="border-top-style:solid;border-top-color:rgb(238,178,17);border-top-width:2px"> 408-460-2413</td></tr></tbody></table></span></div>
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