Fix movable instructions computation in x86-64 detour backend - #53
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dnivra wants to merge 7 commits into
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Fix movable instructions computation in x86-64 detour backend#53dnivra wants to merge 7 commits into
dnivra wants to merge 7 commits into
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instructions containing patch address instead of entire basic block
dnivra
marked this pull request as draft
November 23, 2023 00:29
size of movable basic block
dnivra
marked this pull request as ready for review
November 23, 2023 20:33
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I fixed the x86-64 test cases that failed because of changes in this PR. The sole failing test case fails on master as well and so I think this PR can be merged in. |
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I fixed the failing test case as well. It seems the test case was incorrectly updated in 29c1c57a and so was failing. Since the change is pretty trivial, I included it in this PR too. |
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This PR fixes the movable instructions computation in the x86-64 detour backend (and thus potentially fix #47). Currently, only the last instruction in the block is check if movable or not. As a result, any unmovable instructions in the middle of the block (eg: instructions with RIP relative addressing) will be treated as movable and trigger a fault if moved. This PR fixes the movable instructions computation to exclude such instructions. Technically, RIP relative instructions can be moved - the argument needs to be modified to ensure the reference is still valid. However, I felt excluding them is easier to implement and so went down that route. If we want to treat RIP relative instructions as movable, I can look into doing that.