[llvm] [llvm-exegesis] Add explicit error message with segfault address (PR #74210)

[Aiden Grossman via llvm-commits]

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@@ -2,7 +2,7 @@
 
 # RUN: llvm-exegesis -mtriple=x86_64-unknown-unknown -mode=latency -snippets-file=%s -execution-mode=subprocess | FileCheck %s
 
-# CHECK: error:           'The benchmarking subprocess sent unexpected signal: Segmentation fault'
+# CHECK: error:           The snippet crashed with signal Segmentation fault at address 10000
 
-# LLVM-EXEGESIS-DEFREG RBX 0
+# LLVM-EXEGESIS-DEFREG RBX 10000
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boomanaiden154 wrote:

Good point. `10000` probably shouldn't be mapped, but it's exactly at the lower limit that most Linux distributions allow. I'll change it to something within the first couple pages which won't completely guarantee that nothing is mapped there, but should in all practical cases, especially since most distributions prevent running `mmap` with an address below `0x10000` (at least without additional permissions).

https://github.com/llvm/llvm-project/pull/74210