Fix node hash metadata in cross-arch situations #8361
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…thestinger When running rusti 32-bit tests from a 64-bit host, these errors came up frequently. My best idea as to what was happening is: 1. First, if you hash the same `int` value on 32-bit and 64-bit, you will get two different hashes. 2. In a cross-compile situation, let's say x86_64 is building an i686 library, all of the hashes will be 64-bit hashes. 3. Then let's say you use the i686 libraries and then attempt to link against the same i686 libraries, because you're calculating hashes with a 32-bit int instead of a 64-bit one, you'll have different hashes and you won't be able to find items in the metadata (the items were generated with a 64-bit int). This patch changes the items to always be hashed as an `i64` to preserve the hash value across architectures. Here's a nice before/after for this patch of the state of rusti tests ``` host target before after 64 64 yes yes 64 32 no no (llvm assertion) 32 64 no yes 32 32 no no (llvm assertion) ``` Basically one case started working, but currently when the target is 32-bit LLVM is having a lot of problems generating code. That's another separate issue though.
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Very subtle. Nice find. |
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When running rusti 32-bit tests from a 64-bit host, these errors came up frequently. My best idea as to what was happening is:
intvalue on 32-bit and 64-bit, you will get two different hashes.This patch changes the items to always be hashed as an
i64to preserve the hash value across architectures. Here's a nice before/after for this patch of the state of rusti testsBasically one case started working, but currently when the target is 32-bit LLVM is having a lot of problems generating code. That's another separate issue though.