[llvm] r360138 - [llvm-exegesis] BenchmarkRunner::runConfiguration(): write small snippet to memory

[Roman Lebedev via llvm-commits]

Author: lebedevri
Date: Tue May  7 05:28:08 2019
New Revision: 360138

URL: http://llvm.org/viewvc/llvm-project?rev=360138&view=rev
Log:
[llvm-exegesis] BenchmarkRunner::runConfiguration(): write small snippet to memory

It was previously writing this temporary snippet to file,
then reading it back, but leaving the tmp file in place.
This is both unefficient, and results in huge garbage pileup
in /tmp.

One would have thought it would have been caught during D60317..

Modified:
    llvm/trunk/tools/llvm-exegesis/lib/BenchmarkRunner.cpp

Modified: llvm/trunk/tools/llvm-exegesis/lib/BenchmarkRunner.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-exegesis/lib/BenchmarkRunner.cpp?rev=360138&r1=360137&r2=360138&view=diff
==============================================================================
--- llvm/trunk/tools/llvm-exegesis/lib/BenchmarkRunner.cpp (original)
+++ llvm/trunk/tools/llvm-exegesis/lib/BenchmarkRunner.cpp Tue May  7 05:28:08 2019
@@ -117,14 +117,13 @@ BenchmarkRunner::runConfiguration(const
   // that the inside instructions are repeated.
   constexpr const int kMinInstructionsForSnippet = 16;
   {
-    auto ObjectFilePath = writeObjectFile(
-        BC, GenerateInstructions(BC, kMinInstructionsForSnippet));
-    if (llvm::Error E = ObjectFilePath.takeError()) {
-      InstrBenchmark.Error = llvm::toString(std::move(E));
-      return InstrBenchmark;
-    }
+    llvm::SmallString<0> Buffer;
+    llvm::raw_svector_ostream OS(Buffer);
+    assembleToStream(State.getExegesisTarget(), State.createTargetMachine(),
+                     BC.LiveIns, BC.RegisterInitialValues,
+                     GenerateInstructions(BC, kMinInstructionsForSnippet), OS);
     const ExecutableFunction EF(State.createTargetMachine(),
-                                getObjectFromFile(*ObjectFilePath));
+                                getObjectFromBuffer(OS.str()));
     const auto FnBytes = EF.getFunctionBytes();
     InstrBenchmark.AssembledSnippet.assign(FnBytes.begin(), FnBytes.end());
   }