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<p>Both should be fixed in 346416.</p>
<p><br>
</p>
<p>Philip</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 11/8/18 9:06 AM, Jordan Rudd wrote:<br>
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Yes, that's more clear (you duplicated the word specified, minor
typo).</div>
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<br>
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<div style="font-family: Calibri, Helvetica, sans-serif;
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The other part that threw me off was that the section name was
only identified "for Darwin." I was able to find the section via
assembly inspection, but that threw me off a bit.</div>
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<div id="divRplyFwdMsg" dir="ltr"><font style="font-size:11pt"
face="Calibri, sans-serif" color="#000000"><b>From:</b> Philip
Reames <a class="moz-txt-link-rfc2396E" href="mailto:listmail@philipreames.com"><listmail@philipreames.com></a><br>
<b>Sent:</b> Thursday, November 8, 2018 7:21 AM<br>
<b>To:</b> Jordan Rudd; <a class="moz-txt-link-abbreviated" href="mailto:llvm-dev@lists.llvm.org">llvm-dev@lists.llvm.org</a><br>
<b>Subject:</b> Re: [llvm-dev] Building GC on
statepoint-example</font>
<div> </div>
</div>
<div style="background-color:#FFFFFF">
<p>Jordon,</p>
<p><br>
</p>
<p>I just submitted a change to the docs to hopefully address
your confusion. Can you take a look and let me know if you
have further questions? Start with the revised Stack Map
Format section.</p>
<p><br>
</p>
<p>Philip</p>
<p><br>
</p>
<p>p.s. I just submitted this and it'll take a few minutes to
refresh. In the meantime, you could look at the diff for
346405.<br>
</p>
<p><br>
</p>
<div class="x_moz-cite-prefix">On 11/2/18 2:52 PM, Jordan Rudd
via llvm-dev wrote:<br>
</div>
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Note: These instructions seem to be targeted towards people
creating a JIT. My compiler compiles to native. I suppose I
just need a reference to the stack location of the stack
map, wherever that is.</div>
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<div id="x_divRplyFwdMsg" dir="ltr"><font
style="font-size:11pt" face="Calibri, sans-serif"
color="#000000"><b>From:</b> llvm-dev
<a class="x_moz-txt-link-rfc2396E"
href="mailto:llvm-dev-bounces@lists.llvm.org"
moz-do-not-send="true">
<llvm-dev-bounces@lists.llvm.org></a> on behalf of
Jordan Rudd via llvm-dev <a
class="x_moz-txt-link-rfc2396E"
href="mailto:llvm-dev@lists.llvm.org"
moz-do-not-send="true">
<llvm-dev@lists.llvm.org></a><br>
<b>Sent:</b> Thursday, November 1, 2018 2:06 PM<br>
<b>To:</b> <a class="x_moz-txt-link-abbreviated"
href="mailto:llvm-dev@lists.llvm.org"
moz-do-not-send="true">
llvm-dev@lists.llvm.org</a><br>
<b>Subject:</b> [llvm-dev] Building GC on
statepoint-example</font>
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Hi,</div>
<div style="font-family:Calibri,Helvetica,sans-serif;
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<br>
</div>
<div style="font-family:Calibri,Helvetica,sans-serif;
font-size:12pt; color:rgb(0,0,0)">
I'm trying to build a gc using the statepoint-example
strategy. However, after hours of searching, reading
documentation and trying to find code examples online, I
cannot figure out how to access the Stack Map.</div>
<div style="font-family:Calibri,Helvetica,sans-serif;
font-size:12pt; color:rgb(0,0,0)">
<br>
</div>
<div style="font-family:Calibri,Helvetica,sans-serif;
font-size:12pt; color:rgb(0,0,0)">
The documentation for statepoint-example says:</div>
<div style="font-family:Calibri,Helvetica,sans-serif;
font-size:12pt; color:rgb(0,0,0)">
<br>
</div>
<div style="font-family:Calibri,Helvetica,sans-serif;
font-size:12pt; color:rgb(0,0,0)">
<i><span style="">The stack map format generated by this
GC strategy can be found in the<span> </span></span><a
href="https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fllvm.org%2Fdocs%2FStackMaps.html%23stackmap-section&data=02%7C01%7C%7C0d564a3c7b9a42962e2608d6458de2c0%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636772873036011590&sdata=5TKPXTyU5xCrGx67PXW%2FfOHUxhmBJxLAFh1Qckj7jMk%3D&reserved=0"
originalsrc="https://llvm.org/docs/StackMaps.html#stackmap-section"
shash="se7AxZJlxMN+he91+uaVooQYxGnQPptuKz0umeSxtwO7SC5B6QMj+Bp+JVhhjWXdnFvn44471B0L1hSDjxq5Iqq+cjGGUwfBiW2vF4e1E4wI/rVWvBjutW4RPLfymsUtsPt8yhQHszinXUk/jOhy3iNmP3bBUyMuajN9K6jLdCE="
style="" moz-do-not-send="true"><span>Stack Map
Section</span></a><span style=""><span> </span>using
a format documented<span> </span></span><a
href="https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fllvm.org%2Fdocs%2FStatepoints.html%23statepoint-stackmap-format&data=02%7C01%7C%7C0d564a3c7b9a42962e2608d6458de2c0%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636772873036011590&sdata=HXlqIsOn9UXV8kCW508RVYs4UaGk6sDG8VfjmzCHiOc%3D&reserved=0"
originalsrc="https://llvm.org/docs/Statepoints.html#statepoint-stackmap-format"
shash="g9NLTkx0tI98/wLG9ce2/UcQ5xERrTHrJKs0C7J6oyzmAbg+le7N48v/TA/LZBeO66Vw/gNB7mwLkhky9LMs1y0bdHArzp/RRTMM1F6CZZ0Cv84eU7zImYh6HtQmzcLRXWiVZe+/S+4NhbAUV7oJxHbyD/2/NphYPjYheDyZJwc="
style="" moz-do-not-send="true"><span>here</span></a><span
style="">. This format is intended to be the standard
format supported by LLVM going forward.</span></i><br>
</div>
<div style="font-family:Calibri,Helvetica,sans-serif;
font-size:12pt; color:rgb(0,0,0)">
<span style=""><br>
</span></div>
<div style="font-family:Calibri,Helvetica,sans-serif;
font-size:12pt; color:rgb(0,0,0)">
<span style="">Ok, great, I see the format. But... how do
I access the Stack Map from my runtime? Where is it? </span></div>
<div style="font-family:Calibri,Helvetica,sans-serif;
font-size:12pt; color:rgb(0,0,0)">
<span style=""><br>
</span></div>
<div style="font-family:Calibri,Helvetica,sans-serif;
font-size:12pt; color:rgb(0,0,0)">
<span style="">The link seems to send me to this
instruction:</span></div>
<div style="font-family:Calibri,Helvetica,sans-serif;
font-size:12pt; color:rgb(0,0,0)">
<span style=""><br>
</span></div>
<div style="font-family:Calibri,Helvetica,sans-serif;
font-size:12pt; color:rgb(0,0,0)">
<span style=""><i><span style="font-size:14px;
background-color:rgb(255,255,255);
display:inline!important">A JIT compiler can easily
access this section by providing its own memory
manager via the LLVM C API</span><code style=""><span
style="">LLVMCreateSimpleMCJITMemoryManager()</span></code><span
style="font-size:14px;
background-color:rgb(255,255,255);
display:inline!important">. When creating the memory
manager, the JIT provides a callback:</span><code
style=""><span style="">LLVMMemoryManagerAllocateDataSectionCallback()</span></code><span
style="font-size:14px;
background-color:rgb(255,255,255);
display:inline!important">. When LLVM creates this
section, it invokes the callback and passes the
section name.</span></i><br>
</span></div>
<div style="font-family:Calibri,Helvetica,sans-serif;
font-size:12pt; color:rgb(0,0,0)">
<span style=""><span style="font-size:14px;
background-color:rgb(255,255,255);
display:inline!important"><br>
</span></span></div>
<div style="color:rgb(0,0,0)"><font face="Lucida Grande,
Lucida
 Sans Unicode, Geneva, Verdana, sans-serif"><span
style="font-size:14px">None of these API's are
well-documented, so I'm kind of trying to guess what
to do here. As a proof of concept, I tried building a
do-nothing memory manager that
calls APILLVMCreateSimpleMCJITMemoryManager on static
initialization and passes the callbacks to it. I link
the necessary llvm libs into my runtime and fire it
up.<br>
<br>
I can confirm that my safepoint poll code is getting
hit. I can confirm that creating the "memory manager"
is called on runtime boot and that it's succeeding.
But the callbacks never get hit. Even if they were,
it's unclear how I would use the parameters of those
callbacks to locate the stack map.</span></font></div>
<div style="color:rgb(0,0,0)"><font face="Lucida Grande,
Lucida
 Sans Unicode, Geneva, Verdana, sans-serif"><span
style="font-size:14px"><br>
</span></font></div>
<div style="color:rgb(0,0,0)"><font face="Lucida Grande,
Lucida
 Sans Unicode, Geneva, Verdana, sans-serif"><span
style="font-size:14px">What am I missing? </span></font></div>
<div style="color:rgb(0,0,0)"><font face="Lucida Grande,
Lucida
 Sans Unicode, Geneva, Verdana, sans-serif"><span
style="font-size:14px"><br>
</span></font></div>
<div style="color:rgb(0,0,0)"><font face="Lucida Grande,
Lucida
 Sans Unicode, Geneva, Verdana, sans-serif"><span
style="font-size:14px">Thanks!</span></font></div>
<div style="color:rgb(0,0,0)"><font face="Lucida Grande,
Lucida
 Sans Unicode, Geneva, Verdana, sans-serif"><span
style="font-size:14px">Jordan</span></font></div>
</div>
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