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

[Lakshay Kumar via llvm-commits]

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@@ -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)
+             << " more instructions)\n";
+    } else {
+      // Print all middle lines
+      for (size_t i = PreviewFirst; i < N - PreviewLast; ++i) {
+        dbgs() << format_hex_no_prefix(Instructions[i].second.first, 0) << ":\t"
+               << Instructions[i].second.second << Instructions[i].first
+               << '\n';
+      }
+    }
+    // Print last "PreviewLast" lines
+    for (size_t i = N - PreviewLast; i < N; ++i) {
+      dbgs() << format_hex_no_prefix(Instructions[i].second.first, 0) << ":\t"
+             << Instructions[i].second.second << Instructions[i].first << '\n';
+    }
+  }
+  dbgs() << "```\n";
+}
+
+// Function to extract and print assembly from snippet
+void printAssembledSnippet(const LLVMState &State,
+                           const SmallString<0> &Snippet) {
+  // Extract the actual function bytes from the object file
+  std::vector<uint8_t> FunctionBytes;
+  if (auto Err = getBenchmarkFunctionBytes(Snippet, FunctionBytes)) {
+    dbgs() << "Failed to extract function bytes: " << toString(std::move(Err))
+           << "\n";
+    return;
+  }
+
+  DisassemblerHelper DisHelper(State);
+  ArrayRef<uint8_t> Bytes(FunctionBytes);
+
+  // Decode all instructions first
+  std::vector<std::pair<std::string, std::pair<uint64_t, std::string>>>
+      Instructions;
+  uint64_t Address = 0;
+
+  while (!Bytes.empty()) {
+    MCInst Inst;
+    uint64_t Size;
+    if (DisHelper.decodeInst(Inst, Size, Bytes)) {
----------------
lakshayk-nv wrote:

Thanks! Makes Sense.
Resolved

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