[llvm] [llvm-exegesis] [AArch64] Resolving Illegal Instruction Error (PR #132346)

[Sjoerd Meijer via llvm-commits]

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@@ -35,6 +35,14 @@ const ExegesisTarget *ExegesisTarget::lookup(Triple TT) {
   return nullptr;
 }
 
+static bool isPointerAuthOpcode(unsigned Opcode) {
+  return (Opcode >= 1648 && Opcode <= 1667); // AUT instruction class range
----------------
sjoerdmeijer wrote:

I also tried AUTDA, I am looking now but can't find my reproducer anymore. :( 
I rationalised the error because the pointer wasn't signed with PACDA, so this was testing the AUTDA instruction in "isolation". It was a variant of what llvm-exegesis will generate at the moment:

    0000000000000000 <foo>:
       0: f81f0ff6      str     x22, [sp, #-0x10]!
       4: d280000a      mov     x10, #0x0               // =0
       8: d2800016      mov     x22, #0x0               // =0
       c: dac11aca      autda   x10, x22
      10: f84107f6      ldr     x22, [sp], #0x10
      14: d65f03c0      ret

I simplified that, tried different variants. I created another with PACDA+AUTDA that worked, I think, then came to conclusion it was the missing PACDA. Does that makes sense? 

Either way, this snippet segfaults (raises an illegal instruction error), so temporarily disable this?



https://github.com/llvm/llvm-project/pull/132346