Clean up treatment of fast-math flags during parsing #161
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
|
@kquick, can you verify if this PR is sufficient to allow your PX4_Autopilot example from #158 (comment) to be parsed? It works for my (probably much smaller) test case, so I'm curious if that's enough to make your larger example work as well. |
Currently, `llvm-pretty-bc-parser` skips over fast-math flags when parsing. However, it was doing so incorrectly when parsing `FUNC_CODE_INST_CMP2` (i.e., `fcmp` instructions). Per the LLVM source code [here](https://github.com/llvm/llvm-project/blob/b0391dfc737ede147e128fe877045f61fc5e4905/llvm/lib/Bitcode/Reader/BitcodeReader.cpp#L4342-L4377), the fast-math flags are expected to come after all of the other fields, but the code in `llvm-pretty-bc-parser` was assuming that they would appear in the middle. See #158. I addresses this issue by parsing all of the other fields upfront and avoiding parsing the last part, which correspond to fast-math flags. While I was in town, I also made sure to add comments in every other place in the parser where we avoid parsing fast-math flags.
|
I'd try to check the PX4-Autopilot code myself, but I can't even figure out how to build that repo with |
|
In any case, this definitely fixes the bugs in #158 (comment) and #158 (comment), which are cropping up in SV-COMP benchmarks. In light of this, I'm going to go ahead and merge this. I'll leave #158 open as a reminder to check PX4_Autopilot. |
RyanGlScott
added a commit
to GaloisInc/crucible
that referenced
this pull request
Sep 16, 2021
This bumps the `llvm-pretty` and `llvm-pretty-bc-parser` submodules to include the following changes: * GaloisInc/llvm-pretty#85 and GaloisInc/llvm-pretty-bc-parser#166, which adds support for the `freeze` instruction introduced in LLVM 12. * GaloisInc/llvm-pretty#84 and GaloisInc/llvm-pretty-bc-parser#164, which allows parsing `DIEnumerator`s on LLVM 12 or later. * GaloisInc/llvm-pretty#83 and GaloisInc/llvm-pretty-bc-parser#162, which allows parsing `DICompositeType`s on LLVM 12 or later. * GaloisInc/llvm-pretty-bc-parser#161, which allows parsing `fcmp` instructions with fast-math flags. The `freeze` instruction will require some changes in `crucible-llvm` to accommodate, but I will do that in a subsequent commit.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Currently,
llvm-pretty-bc-parserskips over fast-math flags when parsing. However, it was doing so incorrectly when parsingFUNC_CODE_INST_CMP2(i.e.,fcmpinstructions). Per the LLVM source code here, the fast-math flags are expected to come after all of the other fields, but the code inllvm-pretty-bc-parserwas assuming that they would appear in the middle. See #158.I addresses this issue by parsing all of the other fields upfront and avoiding parsing the last part, which correspond to fast-math flags. While I was in town, I also made sure to add comments in every other place in the parser where we avoid parsing fast-math flags.