[llvm] [llvm-exegesis] Debug generated disassembly (PR #142540)

[Sjoerd Meijer via llvm-commits]

================
@@ -588,6 +594,99 @@ class SubProcessFunctionExecutorImpl
   const std::optional<int> BenchmarkProcessCPU;
 };
 #endif // __linux__
+
+// Helper function to print generated assembly snippets
+void printGeneratedAssembly(
+    const std::vector<std::pair<std::string, std::pair<uint64_t, std::string>>>
+        &Instructions,
+    bool Preview, size_t PreviewFirst = 10, size_t PreviewLast = 3) {
+  dbgs() << "```\n";
+  size_t N = Instructions.size();
+  // Print first "PreviewFirst" lines or all if less
+  for (size_t i = 0; i < std::min(size_t(PreviewFirst), N); ++i) {
+    dbgs() << format_hex_no_prefix(Instructions[i].second.first, 0) << ":\t"
+           << Instructions[i].second.second << Instructions[i].first << '\n';
+  }
+  if (N > (PreviewFirst + PreviewLast)) {
+    if (Preview) {
+      dbgs() << "...\t(" << (N - PreviewFirst - PreviewLast)
----------------
sjoerdmeijer wrote:

So yeah, debug vs. release builds had me confused earlier. I guess this debug stream is available even in non-Debug mode, but does it make sense to use `outs()` instead? I see that being used elsewhere, and guess that is the slightly more appropriate output stream for this?

https://github.com/llvm/llvm-project/pull/142540