Add fast-paths for ToolLocationHelper property functions

src/Build.UnitTests/Evaluation/Expander_Tests.cs

@@ -5207,5 +5207,58 @@ public void PropertyFunctionRegisterBuildCheck()
                 logger.AllBuildEvents.Count.ShouldBe(1);
             }
         }
+
+        /// <summary>
+        /// Test ToolLocationHelper.GetPlatformSDKLocation fast path
+        /// </summary>
+        [Fact]
+        public void PropertyFunctionToolLocationHelperGetPlatformSDKLocation()
+        {
+            PropertyDictionary<ProjectPropertyInstance> pg = new PropertyDictionary<ProjectPropertyInstance>();
+
+            Expander<ProjectPropertyInstance, ProjectItemInstance> expander = new Expander<ProjectPropertyInstance, ProjectItemInstance>(pg, FileSystems.Default);
+
+            // This should use the fast path and not throw even if the SDK doesn't exist
+            string result = expander.ExpandIntoStringLeaveEscaped("$([Microsoft.Build.Utilities.ToolLocationHelper]::GetPlatformSDKLocation('Windows', '10.0'))", ExpanderOptions.ExpandProperties, MockElementLocation.Instance);
+
+            // The result could be empty if SDK is not installed, but it should not throw
+            result.ShouldNotBeNull();
+        }
+
+        /// <summary>
+        /// Test ToolLocationHelper.GetPlatformSDKDisplayName fast path
+        /// </summary>
+        [Fact]
+        public void PropertyFunctionToolLocationHelperGetPlatformSDKDisplayName()
+        {
+            PropertyDictionary<ProjectPropertyInstance> pg = new PropertyDictionary<ProjectPropertyInstance>();
+
+            Expander<ProjectPropertyInstance, ProjectItemInstance> expander = new Expander<ProjectPropertyInstance, ProjectItemInstance>(pg, FileSystems.Default);
+
+            // This should use the fast path and not throw even if the SDK doesn't exist
+            string result = expander.ExpandIntoStringLeaveEscaped("$([Microsoft.Build.Utilities.ToolLocationHelper]::GetPlatformSDKDisplayName('Windows', '10.0'))", ExpanderOptions.ExpandProperties, MockElementLocation.Instance);
+
+            // The result could be a generated default name if SDK is not installed, but it should not throw
+            result.ShouldNotBeNull();
+        }
+
+        /// <summary>
+        /// Test that both ToolLocationHelper methods work together in the same property expansion
+        /// </summary>
+        [Fact]
+        public void PropertyFunctionToolLocationHelperBothMethodsTogether()
+        {
+            PropertyDictionary<ProjectPropertyInstance> pg = new PropertyDictionary<ProjectPropertyInstance>();
+
+            Expander<ProjectPropertyInstance, ProjectItemInstance> expander = new Expander<ProjectPropertyInstance, ProjectItemInstance>(pg, FileSystems.Default);
+
+            // Test both methods in sequence
+            string result1 = expander.ExpandIntoStringLeaveEscaped("$([Microsoft.Build.Utilities.ToolLocationHelper]::GetPlatformSDKLocation('Windows', '10.0'))", ExpanderOptions.ExpandProperties, MockElementLocation.Instance);
+            string result2 = expander.ExpandIntoStringLeaveEscaped("$([Microsoft.Build.Utilities.ToolLocationHelper]::GetPlatformSDKDisplayName('Windows', '10.0'))", ExpanderOptions.ExpandProperties, MockElementLocation.Instance);
+
+            // Both should complete without throwing
+            result1.ShouldNotBeNull();
+            result2.ShouldNotBeNull();
+        }
     }
 }

src/Build/Evaluation/Expander/WellKnownFunctions.cs

@@ -898,6 +898,35 @@ internal static bool TryExecuteWellKnownFunction(string methodName, Type receive
                         }
                     }
                 }
+                else if (receiverType.FullName == "Microsoft.Build.Utilities.ToolLocationHelper")
+                {
+                    if (string.Equals(methodName, "GetPlatformSDKLocation", StringComparison.OrdinalIgnoreCase))
+                    {
+                        if (ParseArgs.TryGetArgs(args, out string? arg0, out string? arg1))
+                        {
+                            // Use reflection to invoke the method, but avoid the expensive binding process
+                            var method = receiverType.GetMethod("GetPlatformSDKLocation", new[] { typeof(string), typeof(string) });
+                            if (method != null)
+                            {
+                                returnVal = method.Invoke(null, new object?[] { arg0, arg1 });
+                                return true;
+                            }
+                        }
+                    }
+                    else if (string.Equals(methodName, "GetPlatformSDKDisplayName", StringComparison.OrdinalIgnoreCase))
+                    {
+                        if (ParseArgs.TryGetArgs(args, out string? arg0, out string? arg1))
+                        {
+                            // Use reflection to invoke the method, but avoid the expensive binding process
+                            var method = receiverType.GetMethod("GetPlatformSDKDisplayName", new[] { typeof(string), typeof(string) });
+                            if (method != null)
+                            {
+                                returnVal = method.Invoke(null, new object?[] { arg0, arg1 });
+                                return true;
+                            }
+                        }
+                    }
+                }
                 else if (string.Equals(methodName, nameof(Regex.Replace), StringComparison.OrdinalIgnoreCase) && args.Length == 3)
                 {
                     if (ParseArgs.TryGetArgs(args, out string? arg1, out string? arg2, out string? arg3) && arg1 != null && arg2 != null && arg3 != null)