[PATCH] D76398: [X86] Limit prefix padding w/target specific padding amount

[Philip Reames via Phabricator via llvm-commits]

reames marked an inline comment as done.
reames added inline comments.


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Comment at: llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp:846
+    // TODO: This should probably be '3' once we validate that escape sequences
+    // are conservatively handled.
+    return 0;
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craig.topper wrote:
> What does conservatively handled mean here?
Basically, do all targets have the right setting for the number of prefixes allowed (proxied by nop length atm) and that escape bytes are counted where appropriate.  (e.g. atom can decode three prefixes, but silvermont only gets three of either prefix or escape bytes.)

I haven't dug through all the code involved to figure out escape bytes are represented.  In some cases, we appear to treat them as prefixes, but I'm not sure this handling is universal.  This why I'm disabling prefix padding on targets which need to care about presence of escape bytes.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D76398/new/

https://reviews.llvm.org/D76398