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

[Lakshay Kumar via llvm-commits]

https://github.com/lakshayk-nv updated https://github.com/llvm/llvm-project/pull/142540

>From 3c9421c4185a27e8e6256f41b0e9e8898b08ad41 Mon Sep 17 00:00:00 2001
From: lakshayk-nv <lakshayk at nvidia.com>
Date: Fri, 30 May 2025 03:46:29 -0700
Subject: [PATCH 1/2] [llvm-exegesis] Added Debug flag for print disassembly
 using objdump

---
 .../llvm-exegesis/lib/BenchmarkRunner.cpp     | 31 +++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp b/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp
index a7771b99e97b1..bc2b0b4750e6a 100644
--- a/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp
+++ b/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp
@@ -29,6 +29,8 @@
 #include <cmath>
 #include <memory>
 #include <string>
+#include "llvm/Support/Debug.h"
+#define DEBUG_TYPE "exegesis-benchmark-runner"
 
 #ifdef __linux__
 #ifdef HAVE_LIBPFM
@@ -709,6 +711,35 @@ std::pair<Error, Benchmark> BenchmarkRunner::runConfiguration(
     }
     outs() << "Check generated assembly with: /usr/bin/objdump -d "
            << *ObjectFilePath << "\n";
+
+    int StdOutFD, StdErrFD;
+    SmallString<128> StdOutFile, StdErrFile;
+    sys::fs::createTemporaryFile("temp-objdump-out", "txt", StdOutFD, StdOutFile);
+    sys::fs::createTemporaryFile("temp-objdump-err", "txt", StdErrFD, StdErrFile);
+
+    std::vector<std::optional<StringRef>> Redirects = {
+        std::nullopt,           // stdin
+        StringRef(StdOutFile),  // stdout
+        StringRef(StdErrFile)   // stderr
+    };
+
+#ifdef __linux__
+    std::string ErrMsg;
+    int Result = sys::ExecuteAndWait(
+        "/usr/bin/objdump", {"/usr/bin/objdump", "-d", *ObjectFilePath},
+        std::nullopt, Redirects, 0, 0, &ErrMsg);
+    auto StdOutBuf = MemoryBuffer::getFile(StdOutFile);
+    if (StdOutBuf && !(*StdOutBuf)->getBuffer().empty())
+      LLVM_DEBUG(dbgs() << "[llvm-exegesis][objdump] Generated assembly:\n"
+                        << (*StdOutBuf)->getBuffer() << '\n');
+    auto StdErrBuf = MemoryBuffer::getFile(StdErrFile);
+    if (StdErrBuf && !(*StdErrBuf)->getBuffer().empty())
+      LLVM_DEBUG(dbgs() << "[llvm-exegesis][objdump] stderr:\n"
+                        << (*StdErrBuf)->getBuffer() << '\n');
+    if (!ErrMsg.empty())
+      LLVM_DEBUG(dbgs() << "[llvm-exegesis][objdump] process error: " << ErrMsg << '\n');
+#endif
+    sys::fs::remove(StdOutFile); sys::fs::remove(StdErrFile);
   }
 
   if (BenchmarkPhaseSelector < BenchmarkPhaseSelectorE::Measure) {

>From 7d61a14b246ebd6b82fe046d63407a813d65da19 Mon Sep 17 00:00:00 2001
From: lakshayk-nv <lakshayk at nvidia.com>
Date: Mon, 2 Jun 2025 22:53:56 -0700
Subject: [PATCH 2/2] [llvm-exegesis] Formatting changes

---
 .../llvm-exegesis/lib/BenchmarkRunner.cpp     | 23 +++++++++++--------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp b/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp
index bc2b0b4750e6a..7c2a6c966106a 100644
--- a/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp
+++ b/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp
@@ -20,6 +20,7 @@
 #include "llvm/ADT/Twine.h"
 #include "llvm/Config/llvm-config.h" // for LLVM_ON_UNIX
 #include "llvm/Support/CrashRecoveryContext.h"
+#include "llvm/Support/Debug.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/MemoryBuffer.h"
@@ -29,7 +30,6 @@
 #include <cmath>
 #include <memory>
 #include <string>
-#include "llvm/Support/Debug.h"
 #define DEBUG_TYPE "exegesis-benchmark-runner"
 
 #ifdef __linux__
@@ -712,18 +712,19 @@ std::pair<Error, Benchmark> BenchmarkRunner::runConfiguration(
     outs() << "Check generated assembly with: /usr/bin/objdump -d "
            << *ObjectFilePath << "\n";
 
+#ifdef __linux__
     int StdOutFD, StdErrFD;
     SmallString<128> StdOutFile, StdErrFile;
-    sys::fs::createTemporaryFile("temp-objdump-out", "txt", StdOutFD, StdOutFile);
-    sys::fs::createTemporaryFile("temp-objdump-err", "txt", StdErrFD, StdErrFile);
-
+    sys::fs::createTemporaryFile("temp-objdump-out", "txt", StdOutFD,
+                                 StdOutFile);
+    sys::fs::createTemporaryFile("temp-objdump-err", "txt", StdErrFD,
+                                 StdErrFile);
     std::vector<std::optional<StringRef>> Redirects = {
-        std::nullopt,           // stdin
-        StringRef(StdOutFile),  // stdout
-        StringRef(StdErrFile)   // stderr
+        std::nullopt,          // stdin
+        StringRef(StdOutFile), // stdout
+        StringRef(StdErrFile)  // stderr
     };
 
-#ifdef __linux__
     std::string ErrMsg;
     int Result = sys::ExecuteAndWait(
         "/usr/bin/objdump", {"/usr/bin/objdump", "-d", *ObjectFilePath},
@@ -737,9 +738,11 @@ std::pair<Error, Benchmark> BenchmarkRunner::runConfiguration(
       LLVM_DEBUG(dbgs() << "[llvm-exegesis][objdump] stderr:\n"
                         << (*StdErrBuf)->getBuffer() << '\n');
     if (!ErrMsg.empty())
-      LLVM_DEBUG(dbgs() << "[llvm-exegesis][objdump] process error: " << ErrMsg << '\n');
+      LLVM_DEBUG(dbgs() << "[llvm-exegesis][objdump] process error: " << ErrMsg
+                        << '\n');
+    sys::fs::remove(StdOutFile);
+    sys::fs::remove(StdErrFile);
 #endif
-    sys::fs::remove(StdOutFile); sys::fs::remove(StdErrFile);
   }
 
   if (BenchmarkPhaseSelector < BenchmarkPhaseSelectorE::Measure) {