Reduce generated code size (#1984)

* don't append a new line for each @DummyUnroll@ (3 * 64 lines of code for ever benchmark)

* remove redundant #if defines

Author: adamsitnik

src/BenchmarkDotNet/Code/CodeGenerator.cs

@@ -37,7 +37,7 @@ internal static string Generate(BuildPartition buildPartition)
 
                 string passArguments = GetPassArguments(benchmark);
 
-                extraDefines.Add($"{provider.ExtraDefines}_{buildInfo.Id}");
+                string compilationId = $"{provider.ReturnsDefinition}_{buildInfo.Id}";
 
                 AddNonEmptyUnique(additionalLogic, benchmark.Descriptor.AdditionalLogic);
 
@@ -64,7 +64,8 @@ internal static string Generate(BuildPartition buildPartition)
                     .Replace("$EngineFactoryType$", GetEngineFactoryTypeName(benchmark))
                     .Replace("$MeasureExtraStats$", buildInfo.Config.HasExtraStatsDiagnoser() ? "true" : "false")
                     .Replace("$DisassemblerEntryMethodName$", DisassemblerConstants.DisassemblerEntryMethodName)
-                    .Replace("$WorkloadMethodCall$", provider.GetWorkloadMethodCall(passArguments)).ToString();
+                    .Replace("$WorkloadMethodCall$", provider.GetWorkloadMethodCall(passArguments))
+                    .RemoveRedundantIfDefines(compilationId);
 
                 benchmarkTypeCode = Unroll(benchmarkTypeCode, benchmark.Job.ResolveValue(RunMode.UnrollFactorCharacteristic, EnvironmentResolver.Instance));
 
@@ -122,6 +123,7 @@ private static string Unroll(string text, int factor)
             const string unrollDirective = "@Unroll@";
             const string dummyUnrollDirective = "@DummyUnroll@";
             const int dummyUnrollFactor = 1 << 6;
+            string dummyUnrolled = string.Join("", Enumerable.Repeat("dummyVar++;", dummyUnrollFactor));
             var oldLines = text.Split('\n');
             var newLines = new List<string>();
             foreach (string line in oldLines)
@@ -134,9 +136,7 @@ private static string Unroll(string text, int factor)
                 }
                 else if (line.Contains(dummyUnrollDirective))
                 {
-                    string newLine = line.Replace(dummyUnrollDirective, "");
-                    for (int i = 0; i < dummyUnrollFactor; i++)
-                        newLines.Add(newLine);
+                    newLines.Add(line.Replace(dummyUnrollDirective, dummyUnrolled));
                 }
                 else
                     newLines.Add(line);
@@ -307,6 +307,31 @@ public SmartStringBuilder Replace(string oldValue, string newValue)
                 return this;
             }
 
+            public string RemoveRedundantIfDefines(string id)
+            {
+                var oldLines = builder.ToString().Split('\n');
+                var newLines = new List<string>();
+                bool keepAdding = true;
+
+                foreach (string line in oldLines)
+                {
+                    if (line.StartsWith("#if RETURNS") || line.StartsWith("#elif RETURNS"))
+                    {
+                        keepAdding = line.Contains(id);
+                    }
+                    else if (line.StartsWith("#endif // RETURNS"))
+                    {
+                        keepAdding = true;
+                    }
+                    else if (keepAdding)
+                    {
+                        newLines.Add(line);
+                    }
+                }
+
+                return string.Join("\n", newLines);
+            }
+
             public override string ToString() => builder.ToString();
         }
     }

src/BenchmarkDotNet/Code/DeclarationsProvider.cs

@@ -30,7 +30,7 @@ internal abstract class DeclarationsProvider
 
         public string IterationCleanupMethodName => Descriptor.IterationCleanupMethod?.Name ?? EmptyAction;
 
-        public abstract string ExtraDefines { get; }
+        public abstract string ReturnsDefinition { get; }
 
         protected virtual Type WorkloadMethodReturnType => Descriptor.WorkloadMethod.ReturnType;
 
@@ -74,7 +74,7 @@ internal class VoidDeclarationsProvider : DeclarationsProvider
     {
         public VoidDeclarationsProvider(Descriptor descriptor) : base(descriptor) { }
 
-        public override string ExtraDefines => "#define RETURNS_VOID";
+        public override string ReturnsDefinition => "RETURNS_VOID";
 
         protected override Type OverheadMethodReturnType => typeof(void);
 
@@ -113,10 +113,10 @@ public override string OverheadImplementation
             }
         }
 
-        public override string ExtraDefines
+        public override string ReturnsDefinition
             => Consumer.IsConsumable(WorkloadMethodReturnType) || Consumer.HasConsumableField(WorkloadMethodReturnType, out _)
-                ? "#define RETURNS_CONSUMABLE"
-                : "#define RETURNS_NON_CONSUMABLE_STRUCT";
+                ? "RETURNS_CONSUMABLE"
+                : "RETURNS_NON_CONSUMABLE_STRUCT";
     }
 
     internal class ByRefDeclarationsProvider : NonVoidDeclarationsProvider
@@ -131,7 +131,7 @@ public ByRefDeclarationsProvider(Descriptor descriptor) : base(descriptor) { }
 
         public override string OverheadImplementation => $"return default(System.{nameof(IntPtr)});";
 
-        public override string ExtraDefines => "#define RETURNS_BYREF";
+        public override string ReturnsDefinition => "RETURNS_BYREF";
 
         public override string WorkloadMethodReturnTypeModifiers => "ref";
     }
@@ -140,7 +140,7 @@ internal class ByReadOnlyRefDeclarationsProvider : ByRefDeclarationsProvider
     {
         public ByReadOnlyRefDeclarationsProvider(Descriptor descriptor) : base(descriptor) { }
 
-        public override string ExtraDefines => "#define RETURNS_BYREF_READONLY";
+        public override string ReturnsDefinition => "RETURNS_BYREF_READONLY";
 
         public override string WorkloadMethodReturnTypeModifiers => "ref readonly";
     }

src/BenchmarkDotNet/Templates/BenchmarkType.txt

@@ -89,19 +89,19 @@
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.NoInlining)]
         private void Dummy1()
         {
-            dummyVar++;@DummyUnroll@
+            @DummyUnroll@
         }
 
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.NoInlining)]
         private void Dummy2()
         {
-            dummyVar++;@DummyUnroll@
+            @DummyUnroll@
         }
 
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.NoInlining)]
         private void Dummy3()
         {
-            dummyVar++;@DummyUnroll@
+            @DummyUnroll@
         }
 
         private $OverheadMethodReturnTypeName$ __Overhead($ArgumentsDefinition$) // __ is to avoid possible name conflict
@@ -449,5 +449,5 @@
                 $WorkloadMethodCall$;
             }
         }
-#endif
+#endif // RETURNS
     }