[PATCH] D67492: [DebugInfo] Add a DW_OP_LLVM_entry_value operation

[Djordje Todorovic via Phabricator via llvm-commits]

djtodoro added inline comments.


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Comment at: llvm/lib/IR/DebugInfoMetadata.cpp:896
       // of following expression should be 1, because we support only
       // entry values of a simple register location.
       return I->get() == expr_op_begin()->get() && I->getArg(0) == 1 &&
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aprantl wrote:
> dstenb wrote:
> > aprantl wrote:
> > > Can someone remind me what the reason for this limitation was again? Do we still need it after this patch?
> > I think that the main (or perhaps only?) reason for this limitation is that we, at emission, currently don't have a good way to calculate the size of the block that the entry value covers, and emit that size as a ULEB128 operand before the block. This patch will not change that.
> I see. Could you please add this to the comment here, so it's clear why the restriction exists and how to lift it in the future?
>I think that the main (or perhaps only?) reason for this limitation is that we, at emission, currently don't have a good way to calculate the size of the block that the entry value covers, and emit that size as a ULEB128 operand before the block.

We also wanted to ensure that LLVM currently only generates entry values of size 1.


Repository:
  rL LLVM

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  https://reviews.llvm.org/D67492/new/

https://reviews.llvm.org/D67492