<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;">Committed in r199508.<div><br><div style=""><div>On Jan 16, 2014, at 2:42 PM, Philip Reames <<a href="mailto:listmail@philipreames.com">listmail@philipreames.com</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite">
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<div class="moz-cite-prefix">Your revised naming scheme would be
fine by me. <br>
<br>
We actually have several different calling conventions in use.
Our compiled-code-to-assembly-stub conventions is quite close to
your proposed CPreservesMost, except that we occasionally use a
dual-register return variant for some calls. Our
compiled-to-compiled convention is a slightly rotated form of the
C calling convention. When we make calls from compiled code into
C code (via a hand written assembly stub), we want to be able to
easily insert a leading argument without having to shift all other
arguments. (i.e. for JNI)<br>
<br>
Things to consider for your documentation:<br>
- Is this defined to match the objc runtime? If so, which? Or is
defined in terms of a variant of the C calling convention which
ObjC happens to use? Or is it defined in terms of purpose and
only valid against code compiled by the same version of LLVM with
the same convention name? (i.e. compatibility guarantees)<br>
- What is the difference between these and existing calling
conventions? In particular, "cold"? When should each be used?<br>
- How should target neutral front ends use the conventions? <br>
<br>
You don't need to answer any of those directly to me. Just
provide some documentation which addresses them to some degree.
(The most important is the first.)<br>
<br>
Philip<br>
<br>
On 1/16/14 11:23 AM, Juergen Ributzka wrote:<br>
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Hi Philip,
<div><br>
</div>
<div>thanks for looking at this. I am definitely open for better
names for the calling conventions. Although I would prefer not
to use GPR or XMM in them, because they are not only meant for
X86. Also on a different architecture with different standard
calling conventions a different mix of registers might make more
sense. ObjC is currently the initial use for this, but we don’t
want to limit it to just this one particular runtime. The more
people can use this the better.</div>
<div><br>
</div>
<div>What about CPreservesMost and CPreservesAll?</div>
<div><br>
</div>
<div>How different is your special calling convention?</div>
<div><br>
</div>
<div>Thanks</div>
<div><br>
</div>
<div>Cheers,</div>
<div>Juergen</div>
<div><br>
</div>
<div> <br>
<div>
<div>On Jan 16, 2014, at 10:45 AM, Philip Reames <<a moz-do-not-send="true" href="mailto:listmail@philipreames.com">listmail@philipreames.com</a>>
wrote:</div>
<br class="Apple-interchange-newline">
<blockquote type="cite">
<div style="font-size: 12px; font-style: normal;
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white-space: normal; widows: auto; word-spacing: 0px;
-webkit-text-stroke-width: 0px;">On 1/16/14 10:39 AM,
Philip Reames wrote:<br>
<blockquote type="cite">My only objection to this patch is
the naming. We also have runtime calls with special
calling conventions, but ours aren't the same as the
ones specified here. Could we rename these?<br>
<br>
A few random ideas for names:<br>
CPreserveGPR<br>
CPreserveGPRXMM<br>
WebKitRuntimeCC<br>
</blockquote>
Correction: ObjCRuntime. It helps if I read the original
email more closely.<br>
<blockquote type="cite"><br>
Also, should these be prefixed with X86_?<br>
<br>
Philip<br>
<br>
On 1/15/14 10:41 AM, Lang Hames wrote:<br>
<blockquote type="cite">Hi Juergen,<br>
<br>
If these calling conventions are intended to be
generic, should a<br>
description be added to the LangRef?<br>
<br>
Otherwise LGTM.<br>
<br>
- Lang.<br>
<br>
On Tue, Jan 14, 2014 at 3:11 PM, Juergen Ributzka <<a moz-do-not-send="true" href="mailto:juergen@apple.com">juergen@apple.com</a>>
wrote:<br>
<blockquote type="cite">ping<br>
<br>
On Jan 10, 2014, at 7:45 PM, Juergen Ributzka <<a moz-do-not-send="true" href="mailto:juergen@apple.com">juergen@apple.com</a>>
wrote:<br>
<br>
<blockquote type="cite">New rebased patch and a
small fix to the label check in the unit test.<br>
<br>
Cheers,<br>
Juergen<br>
<br>
<0002-Add-two-new-calling-conventions-for-runtime-calls.patch><br>
On Jan 10, 2014, at 3:47 PM, Juergen Ributzka <<a moz-do-not-send="true" href="mailto:juergen@apple.com">juergen@apple.com</a>>
wrote:<br>
<br>
<blockquote type="cite">Hi @ll,<br>
<br>
this patch adds two new target-independent
calling conventions for runtime calls - Runtime
and FastRuntime.<br>
<br>
The target-specific implementation for X86-64 is
defined as following:<br>
- Arguments are passed as for the default C
calling convention<br>
- The same applies for the return value(s)<br>
- for runtimecc the callee preserves all
GPRs - except R11<br>
- for fastruntimecc the callee preserves
all GPRs and all XMMs - except R11<br>
<br>
The idea is to provide calling conventions for
calls to very hot runtime functions that are
normally just a few lines of assembly code and
don’t require a lot of registers. This could be
used by the ObjectiveC runtime, or any other
runtime that provides performance critical
functions.<br>
<br>
The FastRuntime CC is intended to be used for
small codes that don’t call any other functions
at all.<br>
The Runtime CC is also intended for small codes
that usually don’t call other functions on the
fast path, but might have to on the slow path.<br>
<br>
Cheers,<br>
Juergen<br>
<br>
<0001-Add-two-new-calling-conventions-for-runtime-calls.patch><br>
<br>
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