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| author | Hal Finkel <hfinkel@anl.gov> | 2015-01-13 17:48:12 +0000 |
|---|---|---|
| committer | Hal Finkel <hfinkel@anl.gov> | 2015-01-13 17:48:12 +0000 |
| commit | 821befd52b933ca65022f79345407f6b6bf0b836 (patch) | |
| tree | 3229072c33e80b4ae61191d3e8e6faf4a7516ce1 /llvm/docs | |
| parent | c4ee2c5188872b5a7a4e0d6379141f65cc7356bd (diff) | |
| download | bcm5719-llvm-821befd52b933ca65022f79345407f6b6bf0b836.tar.gz bcm5719-llvm-821befd52b933ca65022f79345407f6b6bf0b836.zip | |
[PowerPC] Add StackMap/PatchPoint support
This commit does two things:
1. Refactors PPCFastISel to use more of the common infrastructure for call
lowering (this lets us take advantage of this common code for lowering some
common intrinsics, stackmap/patchpoint among them).
2. Adds support for stackmap/patchpoint lowering. For the most part, this is
very similar to the support in the AArch64 target, with the obvious differences
(different registers, NOP instructions, etc.). The test cases are adapted
from the AArch64 test cases.
One difference of note is that the patchpoint call sequence takes 24 bytes, so
you can't use less than that (on AArch64 you can go down to 16). Also, as noted
in the docs, we take the patchpoint address to be the actual code address
(assuming the call is local in the TOC-sharing sense), which should yield
higher performance than generating the full cross-DSO indirect-call sequence
and is likely just as useful for JITed code (if not, we'll change it).
StackMaps and Patchpoints are still marked as experimental, and so this support
is doubly experimental. So go ahead and experiment!
llvm-svn: 225808
Diffstat (limited to 'llvm/docs')
| -rw-r--r-- | llvm/docs/StackMaps.rst | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/llvm/docs/StackMaps.rst b/llvm/docs/StackMaps.rst index bd0fb946f9a..5bb05540dec 100644 --- a/llvm/docs/StackMaps.rst +++ b/llvm/docs/StackMaps.rst @@ -221,6 +221,12 @@ lowered according to the calling convention specified at the intrinsic's callsite. Variants of the intrinsic with non-void return type also return a value according to calling convention. +On PowerPC, note that the ``<target>`` must be the actual intended target of +the indirect call, not the function-descriptor address normally used as the +C/C++ function-pointer representation. As a result, the call target must be +local because no adjustment or restoration of the TOC pointer (in register r2) +will be performed. + Requesting zero patch point arguments is valid. In this case, all variable operands are handled just like ``llvm.experimental.stackmap.*``. The difference is that space will |
