[llvm] [JITLink] Support AArch64 big-endian (BE8) ELF objects (PR #225120)

[Lang Hames via llvm-commits]

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@@ -316,11 +316,12 @@ Error lowerPointer64AuthEdgesToSigningFunction(LinkGraph &G) {
   auto &SigningFunctionBlock = SigningFunctionSym.getBlock();
   auto SigningFunctionBuf = SigningFunctionBlock.getAlreadyMutableContent();
 
-  // Write the instructions to the block content.
+  // Write the instructions to the block content. A64 instructions are always
+  // little-endian encoded regardless of the graph's data endianness (BE8).
   BinaryStreamWriter InstrWriter(
       {reinterpret_cast<uint8_t *>(SigningFunctionBuf.data()),
        SigningFunctionBuf.size()},
-      G.getEndianness());
+      llvm::endianness::little);
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lhames wrote:

Has this been tested? Are there any BE-8 targets that support PAC?

I ask because this change seems to conflict with this comment:
> ... In BE8 mode instructions remain little-endian (the A64 ISA is word-invariant)

https://github.com/llvm/llvm-project/pull/225120