diff --git a/csharp/autobuilder/Semmle.Autobuild.Tests/BuildScripts.cs b/csharp/autobuilder/Semmle.Autobuild.Tests/BuildScripts.cs
index 20d19a3525c..a2e59cf7ac3 100644
--- a/csharp/autobuilder/Semmle.Autobuild.Tests/BuildScripts.cs
+++ b/csharp/autobuilder/Semmle.Autobuild.Tests/BuildScripts.cs
@@ -185,7 +185,7 @@ namespace Semmle.Extraction.Tests
         // Records the arguments passed to StartCallback.
         IList<string> StartCallbackIn = new List<string>();
 
-        void StartCallback(string s)
+        void StartCallback(string s, bool silent)
         {
             StartCallbackIn.Add(s);
         }
@@ -194,7 +194,7 @@ namespace Semmle.Extraction.Tests
         IList<string> EndCallbackIn = new List<string>();
         IList<int> EndCallbackReturn = new List<int>();
 
-        void EndCallback(int ret, string s)
+        void EndCallback(int ret, string s, bool silent)
         {
             EndCallbackReturn.Add(ret);
             EndCallbackIn.Add(s);
@@ -203,7 +203,7 @@ namespace Semmle.Extraction.Tests
         [Fact]
         public void TestBuildCommand()
         {
-            var cmd = BuildScript.Create("abc", "def ghi", null, null);
+            var cmd = BuildScript.Create("abc", "def ghi", false, null, null);
 
             Actions.RunProcess["abc def ghi"] = 1;
             cmd.Run(Actions, StartCallback, EndCallback);
@@ -216,7 +216,7 @@ namespace Semmle.Extraction.Tests
         [Fact]
         public void TestAnd1()
         {
-            var cmd = BuildScript.Create("abc", "def ghi", null, null) & BuildScript.Create("odasa", null, null, null);
+            var cmd = BuildScript.Create("abc", "def ghi", false, null, null) & BuildScript.Create("odasa", null, false, null, null);
 
             Actions.RunProcess["abc def ghi"] = 1;
             cmd.Run(Actions, StartCallback, EndCallback);
@@ -230,7 +230,7 @@ namespace Semmle.Extraction.Tests
         [Fact]
         public void TestAnd2()
         {
-            var cmd = BuildScript.Create("odasa", null, null, null) & BuildScript.Create("abc", "def ghi", null, null);
+            var cmd = BuildScript.Create("odasa", null, false, null, null) & BuildScript.Create("abc", "def ghi", false, null, null);
 
             Actions.RunProcess["abc def ghi"] = 1;
             Actions.RunProcess["odasa "] = 0;
@@ -250,7 +250,7 @@ namespace Semmle.Extraction.Tests
         [Fact]
         public void TestOr1()
         {
-            var cmd = BuildScript.Create("odasa", null, null, null) | BuildScript.Create("abc", "def ghi", null, null);
+            var cmd = BuildScript.Create("odasa", null, false, null, null) | BuildScript.Create("abc", "def ghi", false, null, null);
 
             Actions.RunProcess["abc def ghi"] = 1;
             Actions.RunProcess["odasa "] = 0;
@@ -266,7 +266,7 @@ namespace Semmle.Extraction.Tests
         [Fact]
         public void TestOr2()
         {
-            var cmd = BuildScript.Create("abc", "def ghi", null, null) | BuildScript.Create("odasa", null, null, null);
+            var cmd = BuildScript.Create("abc", "def ghi", false, null, null) | BuildScript.Create("odasa", null, false, null, null);
 
             Actions.RunProcess["abc def ghi"] = 1;
             Actions.RunProcess["odasa "] = 0;
@@ -375,7 +375,7 @@ namespace Semmle.Extraction.Tests
             Actions.RunProcess["cmd.exe /C dotnet --info"] = 0;
             Actions.RunProcess["cmd.exe /C dotnet clean test.csproj"] = 0;
             Actions.RunProcess["cmd.exe /C dotnet restore test.csproj"] = 0;
-            Actions.RunProcess[@"cmd.exe /C C:\odasa\tools\odasa index --auto dotnet build --no-incremental /p:UseSharedCompilation=false test.csproj"] = 0;
+            Actions.RunProcess[@"cmd.exe /C C:\odasa\tools\odasa index --auto dotnet build --no-incremental test.csproj"] = 0;
             Actions.RunProcess[@"cmd.exe /C C:\codeql\tools\java\bin\java -jar C:\codeql\csharp\tools\extractor-asp.jar ."] = 0;
             Actions.RunProcess[@"cmd.exe /C C:\odasa\tools\odasa index --xml --extensions config csproj props xml"] = 0;
             Actions.FileExists["csharp.log"] = true;
@@ -401,6 +401,9 @@ namespace Semmle.Extraction.Tests
         [Fact]
         public void TestLinuxCSharpAutoBuilder()
         {
+            Actions.RunProcess["dotnet --list-runtimes"] = 0;
+            Actions.RunProcessOut["dotnet --list-runtimes"] = @"Microsoft.AspNetCore.App 2.2.5 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
+Microsoft.NETCore.App 2.2.5 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]";
             Actions.RunProcess["dotnet --info"] = 0;
             Actions.RunProcess["dotnet clean test.csproj"] = 0;
             Actions.RunProcess["dotnet restore test.csproj"] = 0;
@@ -424,7 +427,7 @@ namespace Semmle.Extraction.Tests
             Actions.LoadXml["test.csproj"] = xml;
 
             var autobuilder = CreateAutoBuilder("csharp", false);
-            TestAutobuilderScript(autobuilder, 0, 6);
+            TestAutobuilderScript(autobuilder, 0, 7);
         }
 
         [Fact]
@@ -598,6 +601,8 @@ namespace Semmle.Extraction.Tests
         [Fact]
         public void TestLinuxBuildCommand()
         {
+            Actions.RunProcess["dotnet --list-runtimes"] = 1;
+            Actions.RunProcessOut["dotnet --list-runtimes"] = "";
             Actions.RunProcess[@"C:\odasa/tools/odasa index --auto ""./build.sh --skip-tests"""] = 0;
             Actions.RunProcess[@"C:\codeql\tools\java/bin/java -jar C:\codeql\csharp/tools/extractor-asp.jar ."] = 0;
             Actions.RunProcess[@"C:\odasa/tools/odasa index --xml --extensions config csproj props xml"] = 0;
@@ -610,7 +615,7 @@ namespace Semmle.Extraction.Tests
             SkipVsWhere();
 
             var autobuilder = CreateAutoBuilder("csharp", false, buildCommand: "./build.sh --skip-tests");
-            TestAutobuilderScript(autobuilder, 0, 3);
+            TestAutobuilderScript(autobuilder, 0, 4);
         }
 
         [Fact]
@@ -621,6 +626,8 @@ namespace Semmle.Extraction.Tests
             Actions.GetEnvironmentVariable["CODEQL_EXTRACTOR_CSHARP_TRAP_DIR"] = "";
             Actions.GetEnvironmentVariable["CODEQL_EXTRACTOR_CSHARP_SOURCE_ARCHIVE_DIR"] = "";
             Actions.RunProcess["/bin/chmod u+x build/build.sh"] = 0;
+            Actions.RunProcess["dotnet --list-runtimes"] = 1;
+            Actions.RunProcessOut["dotnet --list-runtimes"] = "";
             Actions.RunProcess[@"C:\odasa/tools/odasa index --auto build/build.sh"] = 0;
             Actions.RunProcessWorkingDirectory[@"C:\odasa/tools/odasa index --auto build/build.sh"] = "build";
             Actions.RunProcess[@"C:\codeql\tools\java/bin/java -jar C:\codeql\csharp/tools/extractor-asp.jar ."] = 0;
@@ -628,7 +635,7 @@ namespace Semmle.Extraction.Tests
             Actions.FileExists["csharp.log"] = true;
 
             var autobuilder = CreateAutoBuilder("csharp", false);
-            TestAutobuilderScript(autobuilder, 0, 4);
+            TestAutobuilderScript(autobuilder, 0, 5);
         }
 
         [Fact]
@@ -640,12 +647,14 @@ namespace Semmle.Extraction.Tests
             Actions.GetEnvironmentVariable["CODEQL_EXTRACTOR_CSHARP_SOURCE_ARCHIVE_DIR"] = "";
 
             Actions.RunProcess["/bin/chmod u+x build.sh"] = 0;
+            Actions.RunProcess["dotnet --list-runtimes"] = 1;
+            Actions.RunProcessOut["dotnet --list-runtimes"] = "";
             Actions.RunProcess[@"C:\odasa/tools/odasa index --auto build.sh"] = 0;
             Actions.RunProcessWorkingDirectory[@"C:\odasa/tools/odasa index --auto build.sh"] = "";
             Actions.FileExists["csharp.log"] = false;
 
             var autobuilder = CreateAutoBuilder("csharp", false);
-            TestAutobuilderScript(autobuilder, 1, 2);
+            TestAutobuilderScript(autobuilder, 1, 3);
         }
 
         [Fact]
@@ -657,12 +666,14 @@ namespace Semmle.Extraction.Tests
             Actions.GetEnvironmentVariable["CODEQL_EXTRACTOR_CSHARP_SOURCE_ARCHIVE_DIR"] = "";
 
             Actions.RunProcess["/bin/chmod u+x build.sh"] = 0;
+            Actions.RunProcess["dotnet --list-runtimes"] = 1;
+            Actions.RunProcessOut["dotnet --list-runtimes"] = "";
             Actions.RunProcess[@"C:\odasa/tools/odasa index --auto build.sh"] = 5;
             Actions.RunProcessWorkingDirectory[@"C:\odasa/tools/odasa index --auto build.sh"] = "";
             Actions.FileExists["csharp.log"] = true;
 
             var autobuilder = CreateAutoBuilder("csharp", false);
-            TestAutobuilderScript(autobuilder, 1, 2);
+            TestAutobuilderScript(autobuilder, 1, 3);
         }
 
         [Fact]
@@ -748,7 +759,7 @@ namespace Semmle.Extraction.Tests
             TestAutobuilderScript(autobuilder, 0, 6);
         }
 
-    [Fact]
+        [Fact]
         public void TestWindowCSharpMsBuildMultipleSolutions()
         {
             Actions.RunProcess[@"cmd.exe /C C:\odasa\tools\csharp\nuget\nuget.exe restore test1.csproj"] = 0;
@@ -871,6 +882,9 @@ namespace Semmle.Extraction.Tests
         [Fact]
         public void TestSkipNugetDotnet()
         {
+            Actions.RunProcess["dotnet --list-runtimes"] = 0;
+            Actions.RunProcessOut["dotnet --list-runtimes"] = @"Microsoft.AspNetCore.App 2.1.3 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
+Microsoft.NETCore.App 2.1.3 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]";
             Actions.RunProcess["dotnet --info"] = 0;
             Actions.RunProcess["dotnet clean test.csproj"] = 0;
             Actions.RunProcess["dotnet restore test.csproj"] = 0;
@@ -894,7 +908,7 @@ namespace Semmle.Extraction.Tests
             Actions.LoadXml["test.csproj"] = xml;
 
             var autobuilder = CreateAutoBuilder("csharp", false, dotnetArguments: "--no-restore");  // nugetRestore=false does not work for now.
-            TestAutobuilderScript(autobuilder, 0, 6);
+            TestAutobuilderScript(autobuilder, 0, 7);
         }
 
         [Fact]
@@ -906,10 +920,13 @@ namespace Semmle.Extraction.Tests
             Actions.RunProcess[@"chmod u+x dotnet-install.sh"] = 0;
             Actions.RunProcess[@"./dotnet-install.sh --channel release --version 2.1.3 --install-dir C:\Project/.dotnet"] = 0;
             Actions.RunProcess[@"rm dotnet-install.sh"] = 0;
+            Actions.RunProcess[@"C:\Project/.dotnet/dotnet --list-runtimes"] = 0;
+            Actions.RunProcessOut[@"C:\Project/.dotnet/dotnet --list-runtimes"] = @"Microsoft.AspNetCore.App 3.0.0 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
+Microsoft.NETCore.App 3.0.0 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]";
             Actions.RunProcess[@"C:\Project/.dotnet/dotnet --info"] = 0;
             Actions.RunProcess[@"C:\Project/.dotnet/dotnet clean test.csproj"] = 0;
             Actions.RunProcess[@"C:\Project/.dotnet/dotnet restore test.csproj"] = 0;
-            Actions.RunProcess[@"C:\odasa/tools/odasa index --auto C:\Project/.dotnet/dotnet build --no-incremental /p:UseSharedCompilation=false test.csproj"] = 0;
+            Actions.RunProcess[@"C:\odasa/tools/odasa index --auto C:\Project/.dotnet/dotnet build --no-incremental test.csproj"] = 0;
             Actions.RunProcess[@"C:\codeql\tools\java/bin/java -jar C:\codeql\csharp/tools/extractor-asp.jar ."] = 0;
             Actions.RunProcess[@"C:\odasa/tools/odasa index --xml --extensions config csproj props xml"] = 0;
             Actions.FileExists["csharp.log"] = true;
@@ -930,18 +947,24 @@ namespace Semmle.Extraction.Tests
             Actions.LoadXml["test.csproj"] = xml;
 
             var autobuilder = CreateAutoBuilder("csharp", false, dotnetVersion: "2.1.3");
-            TestAutobuilderScript(autobuilder, 0, 11);
+            TestAutobuilderScript(autobuilder, 0, 12);
         }
 
         [Fact]
         public void TestDotnetVersionAlreadyInstalled()
         {
             Actions.RunProcess["dotnet --list-sdks"] = 0;
-            Actions.RunProcessOut["dotnet --list-sdks"] = "2.1.3 [C:\\Program Files\\dotnet\\sdks]\n2.1.4 [C:\\Program Files\\dotnet\\sdks]";
+            Actions.RunProcessOut["dotnet --list-sdks"] = @"2.1.3 [C:\Program Files\dotnet\sdks]
+2.1.4 [C:\Program Files\dotnet\sdks]";
             Actions.RunProcess[@"curl -L -sO https://dot.net/v1/dotnet-install.sh"] = 0;
             Actions.RunProcess[@"chmod u+x dotnet-install.sh"] = 0;
             Actions.RunProcess[@"./dotnet-install.sh --channel release --version 2.1.3 --install-dir C:\Project/.dotnet"] = 0;
             Actions.RunProcess[@"rm dotnet-install.sh"] = 0;
+            Actions.RunProcess[@"C:\Project/.dotnet/dotnet --list-runtimes"] = 0;
+            Actions.RunProcessOut[@"C:\Project/.dotnet/dotnet --list-runtimes"] = @"Microsoft.AspNetCore.App 2.1.3 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
+Microsoft.AspNetCore.App 2.1.4 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
+Microsoft.NETCore.App 2.1.3 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
+Microsoft.NETCore.App 2.1.4 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]";
             Actions.RunProcess[@"C:\Project/.dotnet/dotnet --info"] = 0;
             Actions.RunProcess[@"C:\Project/.dotnet/dotnet clean test.csproj"] = 0;
             Actions.RunProcess[@"C:\Project/.dotnet/dotnet restore test.csproj"] = 0;
@@ -966,7 +989,7 @@ namespace Semmle.Extraction.Tests
             Actions.LoadXml["test.csproj"] = xml;
 
             var autobuilder = CreateAutoBuilder("csharp", false, dotnetVersion: "2.1.3");
-            TestAutobuilderScript(autobuilder, 0, 11);
+            TestAutobuilderScript(autobuilder, 0, 12);
         }
 
         [Fact]
@@ -979,7 +1002,7 @@ namespace Semmle.Extraction.Tests
             Actions.RunProcess[@"cmd.exe /C C:\Project\.dotnet\dotnet --info"] = 0;
             Actions.RunProcess[@"cmd.exe /C C:\Project\.dotnet\dotnet clean test.csproj"] = 0;
             Actions.RunProcess[@"cmd.exe /C C:\Project\.dotnet\dotnet restore test.csproj"] = 0;
-            Actions.RunProcess[@"cmd.exe /C C:\odasa\tools\odasa index --auto C:\Project\.dotnet\dotnet build --no-incremental /p:UseSharedCompilation=false test.csproj"] = 0;
+            Actions.RunProcess[@"cmd.exe /C C:\odasa\tools\odasa index --auto C:\Project\.dotnet\dotnet build --no-incremental test.csproj"] = 0;
             Actions.RunProcess[@"cmd.exe /C C:\codeql\tools\java\bin\java -jar C:\codeql\csharp\tools\extractor-asp.jar ."] = 0;
             Actions.RunProcess[@"cmd.exe /C C:\odasa\tools\odasa index --xml --extensions config csproj props xml"] = 0;
             Actions.FileExists["csharp.log"] = true;
diff --git a/csharp/autobuilder/Semmle.Autobuild/Autobuilder.cs b/csharp/autobuilder/Semmle.Autobuild/Autobuilder.cs
index 001934f489d..73e6fcd181f 100644
--- a/csharp/autobuilder/Semmle.Autobuild/Autobuilder.cs
+++ b/csharp/autobuilder/Semmle.Autobuild/Autobuilder.cs
@@ -214,8 +214,16 @@ namespace Semmle.Autobuild
             if (Options.IgnoreErrors)
                 script |= BuildScript.Success;
 
-            void startCallback(string s) => Log(Severity.Info, $"\nRunning {s}");
-            void exitCallback(int ret, string msg) => Log(Severity.Info, $"Exit code {ret}{(string.IsNullOrEmpty(msg) ? "" : $": {msg}")}");
+            void startCallback(string s, bool silent)
+            {
+                Log(silent ? Severity.Debug : Severity.Info, $"\nRunning {s}");
+            }
+
+            void exitCallback(int ret, string msg, bool silent)
+            {
+                Log(silent ? Severity.Debug : Severity.Info, $"Exit code {ret}{(string.IsNullOrEmpty(msg) ? "" : $": {msg}")}");
+            }
+
             return script.Run(Actions, startCallback, exitCallback);
         }
 
diff --git a/csharp/autobuilder/Semmle.Autobuild/BuildActions.cs b/csharp/autobuilder/Semmle.Autobuild/BuildActions.cs
index edf4fc752c1..837f6e3f69e 100644
--- a/csharp/autobuilder/Semmle.Autobuild/BuildActions.cs
+++ b/csharp/autobuilder/Semmle.Autobuild/BuildActions.cs
@@ -141,12 +141,8 @@ namespace Semmle.Autobuild
                 pi.WorkingDirectory = workingDirectory;
 
             // Environment variables can only be used when not redirecting stdout
-            if (!redirectStandardOutput)
-            {
-                pi.Environment["UseSharedCompilation"] = "false";
-                if (environment != null)
-                    environment.ForEach(kvp => pi.Environment[kvp.Key] = kvp.Value);
-            }
+            if (!redirectStandardOutput && environment != null)
+                environment.ForEach(kvp => pi.Environment[kvp.Key] = kvp.Value);
             return pi;
         }
 
diff --git a/csharp/autobuilder/Semmle.Autobuild/BuildCommandAutoRule.cs b/csharp/autobuilder/Semmle.Autobuild/BuildCommandAutoRule.cs
index 09c41ccf74c..e7e2c9255dd 100644
--- a/csharp/autobuilder/Semmle.Autobuild/BuildCommandAutoRule.cs
+++ b/csharp/autobuilder/Semmle.Autobuild/BuildCommandAutoRule.cs
@@ -43,9 +43,9 @@ namespace Semmle.Autobuild
             var dir = Path.GetDirectoryName(scriptPath);
 
             // A specific .NET Core version may be required
-            return chmodScript & DotNetRule.WithDotNet(builder, dotNet =>
+            return chmodScript & DotNetRule.WithDotNet(builder, environment =>
             {
-                var command = new CommandBuilder(builder.Actions, dir, dotNet?.Environment);
+                var command = new CommandBuilder(builder.Actions, dir, environment);
 
                 // A specific Visual Studio version may be required
                 var vsTools = MsBuildRule.GetVcVarsBatFile(builder);
diff --git a/csharp/autobuilder/Semmle.Autobuild/BuildCommandRule.cs b/csharp/autobuilder/Semmle.Autobuild/BuildCommandRule.cs
index 2e582b707f2..fe91503ec8f 100644
--- a/csharp/autobuilder/Semmle.Autobuild/BuildCommandRule.cs
+++ b/csharp/autobuilder/Semmle.Autobuild/BuildCommandRule.cs
@@ -11,9 +11,9 @@
                 return BuildScript.Failure;
 
             // Custom build commands may require a specific .NET Core version
-            return DotNetRule.WithDotNet(builder, dotNet =>
+            return DotNetRule.WithDotNet(builder, environment =>
                 {
-                    var command = new CommandBuilder(builder.Actions, null, dotNet?.Environment);
+                    var command = new CommandBuilder(builder.Actions, null, environment);
 
                     // Custom build commands may require a specific Visual Studio version
                     var vsTools = MsBuildRule.GetVcVarsBatFile(builder);
diff --git a/csharp/autobuilder/Semmle.Autobuild/BuildScript.cs b/csharp/autobuilder/Semmle.Autobuild/BuildScript.cs
index a41011e159f..93ea941d58b 100644
--- a/csharp/autobuilder/Semmle.Autobuild/BuildScript.cs
+++ b/csharp/autobuilder/Semmle.Autobuild/BuildScript.cs
@@ -25,7 +25,7 @@ namespace Semmle.Autobuild
         /// an exit message.
         /// </param>
         /// <returns>The exit code from this build script.</returns>
-        public abstract int Run(IBuildActions actions, Action<string> startCallback, Action<int, string> exitCallBack);
+        public abstract int Run(IBuildActions actions, Action<string, bool> startCallback, Action<int, string, bool> exitCallBack);
 
         /// <summary>
         /// Run this build command.
@@ -44,33 +44,36 @@ namespace Semmle.Autobuild
         /// </param>
         /// <param name="stdout">Contents of standard out.</param>
         /// <returns>The exit code from this build script.</returns>
-        public abstract int Run(IBuildActions actions, Action<string> startCallback, Action<int, string> exitCallBack, out IList<string> stdout);
+        public abstract int Run(IBuildActions actions, Action<string, bool> startCallback, Action<int, string, bool> exitCallBack, out IList<string> stdout);
 
         class BuildCommand : BuildScript
         {
             readonly string exe, arguments, workingDirectory;
             readonly IDictionary<string, string> environment;
+            readonly bool silent;
 
             /// <summary>
             /// Create a simple build command.
             /// </summary>
             /// <param name="exe">The executable to run.</param>
             /// <param name="argumentsOpt">The arguments to the executable, or null.</param>
+            /// <param name="silent">Whether this command should run silently.</param>
             /// <param name="workingDirectory">The working directory (<code>null</code> for current directory).</param>
             /// <param name="environment">Additional environment variables.</param>
-            public BuildCommand(string exe, string argumentsOpt, string workingDirectory = null, IDictionary<string, string> environment = null)
+            public BuildCommand(string exe, string argumentsOpt, bool silent, string workingDirectory = null, IDictionary<string, string> environment = null)
             {
                 this.exe = exe;
                 this.arguments = argumentsOpt ?? "";
+                this.silent = silent;
                 this.workingDirectory = workingDirectory;
                 this.environment = environment;
             }
 
             public override string ToString() => exe + " " + arguments;
 
-            public override int Run(IBuildActions actions, Action<string> startCallback, Action<int, string> exitCallBack)
+            public override int Run(IBuildActions actions, Action<string, bool> startCallback, Action<int, string, bool> exitCallBack)
             {
-                startCallback(this.ToString());
+                startCallback(this.ToString(), silent);
                 var ret = 1;
                 var retMessage = "";
                 try
@@ -83,13 +86,13 @@ namespace Semmle.Autobuild
                     retMessage = ex.Message;
                 }
 
-                exitCallBack(ret, retMessage);
+                exitCallBack(ret, retMessage, silent);
                 return ret;
             }
 
-            public override int Run(IBuildActions actions, Action<string> startCallback, Action<int, string> exitCallBack, out IList<string> stdout)
+            public override int Run(IBuildActions actions, Action<string, bool> startCallback, Action<int, string, bool> exitCallBack, out IList<string> stdout)
             {
-                startCallback(this.ToString());
+                startCallback(this.ToString(), silent);
                 var ret = 1;
                 var retMessage = "";
                 try
@@ -102,7 +105,7 @@ namespace Semmle.Autobuild
                     retMessage = ex.Message;
                     stdout = new string[0];
                 }
-                exitCallBack(ret, retMessage);
+                exitCallBack(ret, retMessage, silent);
                 return ret;
             }
 
@@ -116,9 +119,9 @@ namespace Semmle.Autobuild
                 this.func = func;
             }
 
-            public override int Run(IBuildActions actions, Action<string> startCallback, Action<int, string> exitCallBack) => func(actions);
+            public override int Run(IBuildActions actions, Action<string, bool> startCallback, Action<int, string, bool> exitCallBack) => func(actions);
 
-            public override int Run(IBuildActions actions, Action<string> startCallback, Action<int, string> exitCallBack, out IList<string> stdout)
+            public override int Run(IBuildActions actions, Action<string, bool> startCallback, Action<int, string, bool> exitCallBack, out IList<string> stdout)
             {
                 stdout = new string[0];
                 return func(actions);
@@ -142,7 +145,7 @@ namespace Semmle.Autobuild
                 this.s2b = s2;
             }
 
-            public override int Run(IBuildActions actions, Action<string> startCallback, Action<int, string> exitCallBack)
+            public override int Run(IBuildActions actions, Action<string, bool> startCallback, Action<int, string, bool> exitCallBack)
             {
                 int ret1;
                 if (s2a != null)
@@ -155,7 +158,7 @@ namespace Semmle.Autobuild
                 return s2b(ret1).Run(actions, startCallback, exitCallBack);
             }
 
-            public override int Run(IBuildActions actions, Action<string> startCallback, Action<int, string> exitCallBack, out IList<string> stdout)
+            public override int Run(IBuildActions actions, Action<string, bool> startCallback, Action<int, string, bool> exitCallBack, out IList<string> stdout)
             {
                 var ret1 = s1.Run(actions, startCallback, exitCallBack, out var stdout1);
                 var ret2 = (s2a != null ? s2a(stdout1, ret1) : s2b(ret1)).Run(actions, startCallback, exitCallBack, out var stdout2);
@@ -171,10 +174,11 @@ namespace Semmle.Autobuild
         /// Creates a simple build script that runs the specified exe.
         /// </summary>
         /// <param name="argumentsOpt">The arguments to the executable, or null.</param>
+        /// <param name="silent">Whether the executable should run silently.</param>
         /// <param name="workingDirectory">The working directory (<code>null</code> for current directory).</param>
         /// <param name="environment">Additional environment variables.</param>
-        public static BuildScript Create(string exe, string argumentsOpt, string workingDirectory, IDictionary<string, string> environment) =>
-            new BuildCommand(exe, argumentsOpt, workingDirectory, environment);
+        public static BuildScript Create(string exe, string argumentsOpt, bool silent, string workingDirectory, IDictionary<string, string> environment) =>
+            new BuildCommand(exe, argumentsOpt, silent, workingDirectory, environment);
 
         /// <summary>
         /// Creates a simple build script that runs the specified function.
diff --git a/csharp/autobuilder/Semmle.Autobuild/CommandBuilder.cs b/csharp/autobuilder/Semmle.Autobuild/CommandBuilder.cs
index 273cc52b036..7b95e495697 100644
--- a/csharp/autobuilder/Semmle.Autobuild/CommandBuilder.cs
+++ b/csharp/autobuilder/Semmle.Autobuild/CommandBuilder.cs
@@ -17,13 +17,15 @@ namespace Semmle.Autobuild
         readonly EscapeMode escapingMode;
         readonly string workingDirectory;
         readonly IDictionary<string, string> environment;
+        readonly bool silent;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="T:Semmle.Autobuild.CommandBuilder"/> class.
         /// </summary>
         /// <param name="workingDirectory">The working directory (<code>null</code> for current directory).</param>
         /// <param name="environment">Additional environment variables.</param>
-        public CommandBuilder(IBuildActions actions, string workingDirectory = null, IDictionary<string, string> environment = null)
+        /// <param name="silent">Whether this command should be run silently.</param>
+        public CommandBuilder(IBuildActions actions, string workingDirectory = null, IDictionary<string, string> environment = null, bool silent = false)
         {
             arguments = new StringBuilder();
             if (actions.IsWindows())
@@ -40,6 +42,7 @@ namespace Semmle.Autobuild
             firstCommand = true;
             this.workingDirectory = workingDirectory;
             this.environment = environment;
+            this.silent = silent;
         }
 
         void OdasaIndex(string odasa)
@@ -190,6 +193,6 @@ namespace Semmle.Autobuild
         /// <summary>
         /// Returns a build script that contains just this command.
         /// </summary>
-        public BuildScript Script => BuildScript.Create(executable, arguments.ToString(), workingDirectory, environment);
+        public BuildScript Script => BuildScript.Create(executable, arguments.ToString(), silent, workingDirectory, environment);
     }
 }
diff --git a/csharp/autobuilder/Semmle.Autobuild/DotNetRule.cs b/csharp/autobuilder/Semmle.Autobuild/DotNetRule.cs
index 789d68db30a..c9b33cef8d1 100644
--- a/csharp/autobuilder/Semmle.Autobuild/DotNetRule.cs
+++ b/csharp/autobuilder/Semmle.Autobuild/DotNetRule.cs
@@ -5,6 +5,7 @@ using Newtonsoft.Json.Linq;
 using System.Collections.Generic;
 using System.IO;
 using Semmle.Util;
+using System.Text.RegularExpressions;
 
 namespace Semmle.Autobuild
 {
@@ -34,22 +35,20 @@ namespace Semmle.Autobuild
                 builder.Log(Severity.Info, "Attempting to build using .NET Core");
             }
 
-            return WithDotNet(builder, dotNet =>
+            return WithDotNet(builder, (dotNetPath, environment, compatibleClr) =>
                 {
-                    var ret = GetInfoCommand(builder.Actions, dotNet);
+                    var ret = GetInfoCommand(builder.Actions, dotNetPath, environment);
                     foreach (var projectOrSolution in builder.ProjectsOrSolutionsToBuild)
                     {
-                        var cleanCommand = GetCleanCommand(builder.Actions, dotNet);
+                        var cleanCommand = GetCleanCommand(builder.Actions, dotNetPath, environment);
                         cleanCommand.QuoteArgument(projectOrSolution.FullPath);
                         var clean = cleanCommand.Script;
 
-                        var restoreCommand = GetRestoreCommand(builder.Actions, dotNet);
+                        var restoreCommand = GetRestoreCommand(builder.Actions, dotNetPath, environment);
                         restoreCommand.QuoteArgument(projectOrSolution.FullPath);
                         var restore = restoreCommand.Script;
 
-                        var buildCommand = GetBuildCommand(builder, dotNet);
-                        buildCommand.QuoteArgument(projectOrSolution.FullPath);
-                        var build = buildCommand.Script;
+                        var build = GetBuildScript(builder, dotNetPath, environment, compatibleClr, projectOrSolution.FullPath);
 
                         ret &= clean & BuildScript.Try(restore) & build;
                     }
@@ -57,38 +56,73 @@ namespace Semmle.Autobuild
                 });
         }
 
-        /// <summary>
-        /// Returns a script that attempts to download relevant version(s) of the
-        /// .NET Core SDK, followed by running the script generated by <paramref name="f"/>.
-        ///
-        /// The first element <code>DotNetPath</code> of the argument to <paramref name="f"/>
-        /// is the path where .NET Core was installed, and the second element <code>Environment</code>
-        /// is any additional required environment variables. The tuple argument is <code>null</code>
-        /// when the installation failed.
-        /// </summary>
-        public static BuildScript WithDotNet(Autobuilder builder, Func<(string DotNetPath, IDictionary<string, string> Environment)?, BuildScript> f)
+        static BuildScript WithDotNet(Autobuilder builder, Func<string, IDictionary<string, string>, bool, BuildScript> f)
         {
             var installDir = builder.Actions.PathCombine(builder.Options.RootDirectory, ".dotnet");
             var installScript = DownloadDotNet(builder, installDir);
             return BuildScript.Bind(installScript, installed =>
+            {
+                Dictionary<string, string> env;
+                if (installed == 0)
                 {
-                    if (installed == 0)
-                    {
-                        // The installation succeeded, so use the newly installed .NET Core
-                        var path = builder.Actions.GetEnvironmentVariable("PATH");
-                        var delim = builder.Actions.IsWindows() ? ";" : ":";
-                        var env = new Dictionary<string, string>{
+                    // The installation succeeded, so use the newly installed .NET Core
+                    var path = builder.Actions.GetEnvironmentVariable("PATH");
+                    var delim = builder.Actions.IsWindows() ? ";" : ":";
+                    env = new Dictionary<string, string>{
                             { "DOTNET_MULTILEVEL_LOOKUP", "false" }, // prevent look up of other .NET Core SDKs
                             { "DOTNET_SKIP_FIRST_TIME_EXPERIENCE", "true" },
                             { "PATH", installDir + delim + path }
                         };
-                        return f((installDir, env));
+                }
+                else
+                {
+                    installDir = null;
+                    env = null;
+                }
+
+                // The CLR tracer is always compatible on Windows
+                if (builder.Actions.IsWindows())
+                    return f(installDir, env, true);
+
+                // The CLR tracer is only compatible on .NET Core >= 3 on Linux and macOS (see
+                // https://github.com/dotnet/coreclr/issues/19622)
+                return BuildScript.Bind(GetInstalledRuntimesScript(builder.Actions, installDir, env), (runtimes, runtimesRet) =>
+                {
+                    var compatibleClr = false;
+                    if (runtimesRet == 0)
+                    {
+                        var minimumVersion = new Version(3, 0);
+                        var regex = new Regex(@"Microsoft\.NETCore\.App (\d\.\d\.\d)");
+                        compatibleClr = runtimes.
+                            Select(runtime => regex.Match(runtime)).
+                            Where(m => m.Success).
+                            Select(m => m.Groups[1].Value).
+                            Any(m => Version.TryParse(m, out var v) && v >= minimumVersion);
                     }
 
-                    return f(null);
+                    if (!compatibleClr)
+                    {
+                        if (env == null)
+                            env = new Dictionary<string, string>();
+                        env.Add("UseSharedCompilation", "false");
+                    }
+
+                    return f(installDir, env, compatibleClr);
                 });
+            });
         }
 
+        /// <summary>
+        /// Returns a script that attempts to download relevant version(s) of the
+        /// .NET Core SDK, followed by running the script generated by <paramref name="f"/>.
+        ///
+        /// The argument to <paramref name="f"/> is any additional required environment
+        /// variables needed by the installed .NET Core (<code>null</code> when no variables
+        /// are needed).
+        /// </summary>
+        public static BuildScript WithDotNet(Autobuilder builder, Func<IDictionary<string, string>, BuildScript> f)
+            => WithDotNet(builder, (_1, env, _2) => f(env));
+
         /// <summary>
         /// Returns a script for downloading relevant versions of the
         /// .NET Core SDK. The SDK(s) will be installed at <code>installDir</code>
@@ -225,7 +259,7 @@ Invoke-Command -ScriptBlock $ScriptBlock";
 
         static BuildScript GetInstalledSdksScript(IBuildActions actions)
         {
-            var listSdks = new CommandBuilder(actions).
+            var listSdks = new CommandBuilder(actions, silent: true).
                 RunCommand("dotnet").
                 Argument("--list-sdks");
             return listSdks.Script;
@@ -234,38 +268,62 @@ Invoke-Command -ScriptBlock $ScriptBlock";
         static string DotNetCommand(IBuildActions actions, string dotNetPath) =>
             dotNetPath != null ? actions.PathCombine(dotNetPath, "dotnet") : "dotnet";
 
-        BuildScript GetInfoCommand(IBuildActions actions, (string DotNetPath, IDictionary<string, string> Environment)? arg)
+        BuildScript GetInfoCommand(IBuildActions actions, string dotNetPath, IDictionary<string, string> environment)
         {
-            var info = new CommandBuilder(actions, null, arg?.Environment).
-                RunCommand(DotNetCommand(actions, arg?.DotNetPath)).
+            var info = new CommandBuilder(actions, null, environment).
+                RunCommand(DotNetCommand(actions, dotNetPath)).
                 Argument("--info");
             return info.Script;
         }
 
-        CommandBuilder GetCleanCommand(IBuildActions actions, (string DotNetPath, IDictionary<string, string> Environment)? arg)
+        CommandBuilder GetCleanCommand(IBuildActions actions, string dotNetPath, IDictionary<string, string> environment)
         {
-            var clean = new CommandBuilder(actions, null, arg?.Environment).
-                RunCommand(DotNetCommand(actions, arg?.DotNetPath)).
+            var clean = new CommandBuilder(actions, null, environment).
+                RunCommand(DotNetCommand(actions, dotNetPath)).
                 Argument("clean");
             return clean;
         }
 
-        CommandBuilder GetRestoreCommand(IBuildActions actions, (string DotNetPath, IDictionary<string, string> Environment)? arg)
+        CommandBuilder GetRestoreCommand(IBuildActions actions, string dotNetPath, IDictionary<string, string> environment)
         {
-            var restore = new CommandBuilder(actions, null, arg?.Environment).
-                RunCommand(DotNetCommand(actions, arg?.DotNetPath)).
+            var restore = new CommandBuilder(actions, null, environment).
+                RunCommand(DotNetCommand(actions, dotNetPath)).
                 Argument("restore");
             return restore;
         }
 
-        CommandBuilder GetBuildCommand(Autobuilder builder, (string DotNetPath, IDictionary<string, string> Environment)? arg)
+        static BuildScript GetInstalledRuntimesScript(IBuildActions actions, string dotNetPath, IDictionary<string, string> environment)
         {
-            var build = new CommandBuilder(builder.Actions, null, arg?.Environment);
-            return builder.MaybeIndex(build, DotNetCommand(builder.Actions, arg?.DotNetPath)).
+            var listSdks = new CommandBuilder(actions, environment: environment, silent: true).
+                RunCommand(DotNetCommand(actions, dotNetPath)).
+                Argument("--list-runtimes");
+            return listSdks.Script;
+        }
+
+        /// <summary>
+        /// Gets the `dotnet build` script.
+        ///
+        /// The CLR tracer only works on .NET Core >= 3 on Linux and macOS (see
+        /// https://github.com/dotnet/coreclr/issues/19622), so in case we are
+        /// running on an older .NET Core, we disable shared compilation (and
+        /// hence the need for CLR tracing), by adding a
+        /// `/p:UseSharedCompilation=false` argument.
+        /// </summary>
+        BuildScript GetBuildScript(Autobuilder builder, string dotNetPath, IDictionary<string, string> environment, bool compatibleClr, string projOrSln)
+        {
+            var build = new CommandBuilder(builder.Actions, null, environment);
+            var script = builder.MaybeIndex(build, DotNetCommand(builder.Actions, dotNetPath)).
                 Argument("build").
-                Argument("--no-incremental").
-                Argument("/p:UseSharedCompilation=false").
-                Argument(builder.Options.DotNetArguments);
+                Argument("--no-incremental");
+
+            return compatibleClr ?
+                script.Argument(builder.Options.DotNetArguments).
+                    QuoteArgument(projOrSln).
+                    Script :
+                script.Argument("/p:UseSharedCompilation=false").
+                    Argument(builder.Options.DotNetArguments).
+                    QuoteArgument(projOrSln).
+                    Script;
         }
     }
 }