Libraryimport src gen audit

src/libraries/System.Private.CoreLib/src/System/Runtime/InteropServices/Marshalling/AnsiStringMarshaller.cs

@@ -45,6 +45,7 @@ public AnsiStringMarshaller(string? str, Span<byte> buffer)
             }
 
             // >= for null terminator
+            // Use the cast to long to avoid the checked operation
             if ((long)Marshal.SystemMaxDBCSCharSize * str.Length >= buffer.Length)
             {
                 // Calculate accurate byte count when the provided stack-allocated buffer is not sufficient

src/libraries/System.Private.CoreLib/src/System/Runtime/InteropServices/Marshalling/ArrayMarshaller.cs

@@ -66,7 +66,8 @@ public ArrayMarshaller(T[]? array, Span<byte> buffer, int sizeOfNativeElement)
             _managedArray = array;
 
             // Always allocate at least one byte when the array is zero-length.
-            int spaceToAllocate = Math.Max(array.Length * _sizeOfNativeElement, 1);
+            int bufferSize = checked(array.Length * _sizeOfNativeElement);
+            int spaceToAllocate = Math.Max(bufferSize, 1);
             if (spaceToAllocate <= buffer.Length)
             {
                 _span = buffer[0..spaceToAllocate];
@@ -107,7 +108,12 @@ public ArrayMarshaller(T[]? array, Span<byte> buffer, int sizeOfNativeElement)
         /// </remarks>
         public ReadOnlySpan<byte> GetNativeValuesSource(int length)
         {
-            return _allocatedMemory == IntPtr.Zero ? default : _span = new Span<byte>((void*)_allocatedMemory, length * _sizeOfNativeElement);
+            if (_allocatedMemory == IntPtr.Zero)
+                return default;
+
+            int allocatedSize = checked(length * _sizeOfNativeElement);
+            _span = new Span<byte>((void*)_allocatedMemory, allocatedSize);
+            return _span;
         }
 
         /// <summary>

src/libraries/System.Private.CoreLib/src/System/Runtime/InteropServices/Marshalling/PointerArrayMarshaller.cs

@@ -66,7 +66,8 @@ public PointerArrayMarshaller(T*[]? array, Span<byte> buffer, int sizeOfNativeEl
             _managedArray = array;
 
             // Always allocate at least one byte when the array is zero-length.
-            int spaceToAllocate = Math.Max(array.Length * _sizeOfNativeElement, 1);
+            int bufferSize = checked(array.Length * _sizeOfNativeElement);
+            int spaceToAllocate = Math.Max(bufferSize, 1);
             if (spaceToAllocate <= buffer.Length)
             {
                 _span = buffer[0..spaceToAllocate];
@@ -117,7 +118,8 @@ public ReadOnlySpan<byte> GetNativeValuesSource(int length)
             if (_allocatedMemory == IntPtr.Zero)
                 return default;
 
-            _span = new Span<byte>((void*)_allocatedMemory, length * _sizeOfNativeElement);
+            int allocatedSize = checked(length * _sizeOfNativeElement);
+            _span = new Span<byte>((void*)_allocatedMemory, allocatedSize);
             return _span;
         }
 

src/libraries/System.Private.CoreLib/src/System/Runtime/InteropServices/Marshalling/Utf8StringMarshaller.cs

@@ -46,9 +46,10 @@ public Utf8StringMarshaller(string? str, Span<byte> buffer)
             }
 
             const int MaxUtf8BytesPerChar = 3;
+            int maxBytesNeeded = checked(MaxUtf8BytesPerChar * str.Length);
 
             // >= for null terminator
-            if ((long)MaxUtf8BytesPerChar * str.Length >= buffer.Length)
+            if (maxBytesNeeded >= buffer.Length)
             {
                 // Calculate accurate byte count when the provided stack-allocated buffer is not sufficient
                 int exactByteCount = checked(Encoding.UTF8.GetByteCount(str) + 1); // + 1 for null terminator

src/libraries/System.Runtime.InteropServices/gen/LibraryImportGenerator/LibraryImportGenerator.cs

@@ -412,11 +412,11 @@ private static (MemberDeclarationSyntax, ImmutableArray<Diagnostic>) GenerateSou
 
             ImmutableArray<AttributeSyntax> forwardedAttributes = pinvokeStub.ForwardedAttributes;
 
-            const string innerPInvokeName = "__PInvoke__";
+            const string innerPInvokeName = "__PInvoke";
 
             BlockSyntax code = stubGenerator.GeneratePInvokeBody(innerPInvokeName);
 
-            LocalFunctionStatementSyntax dllImport = CreateTargetFunctionAsLocalStatement(
+            LocalFunctionStatementSyntax dllImport = CreateTargetDllImportAsLocalStatement(
                 stubGenerator,
                 options,
                 pinvokeStub.LibraryImportData,
@@ -428,10 +428,7 @@ private static (MemberDeclarationSyntax, ImmutableArray<Diagnostic>) GenerateSou
                 dllImport = dllImport.AddAttributeLists(AttributeList(SeparatedList(forwardedAttributes)));
             }
 
-            dllImport = dllImport.WithLeadingTrivia(
-                Comment("//"),
-                Comment("// Local P/Invoke"),
-                Comment("//"));
+            dllImport = dllImport.WithLeadingTrivia(Comment("// Local P/Invoke"));
             code = code.AddStatements(dllImport);
 
             return (pinvokeStub.ContainingSyntaxContext.WrapMemberInContainingSyntaxWithUnsafeModifier(PrintGeneratedSource(pinvokeStub.StubMethodSyntaxTemplate, pinvokeStub.SignatureContext, code)), pinvokeStub.Diagnostics.AddRange(diagnostics.Diagnostics));
@@ -472,14 +469,14 @@ private static MemberDeclarationSyntax PrintForwarderStub(ContainingSyntax userD
                 .AddAttributeLists(
                     AttributeList(
                         SingletonSeparatedList(
-                            CreateDllImportAttributeFromLibraryImportAttributeData(pinvokeData))));
+                            CreateForwarderDllImport(pinvokeData))));
 
             MemberDeclarationSyntax toPrint = stub.ContainingSyntaxContext.WrapMemberInContainingSyntaxWithUnsafeModifier(stubMethod);
 
             return toPrint;
         }
 
-        private static LocalFunctionStatementSyntax CreateTargetFunctionAsLocalStatement(
+        private static LocalFunctionStatementSyntax CreateTargetDllImportAsLocalStatement(
             PInvokeStubCodeGenerator stubGenerator,
             LibraryImportGeneratorOptions options,
             LibraryImportData libraryImportData,
@@ -491,8 +488,8 @@ private static LocalFunctionStatementSyntax CreateTargetFunctionAsLocalStatement
             (ParameterListSyntax parameterList, TypeSyntax returnType, AttributeListSyntax returnTypeAttributes) = stubGenerator.GenerateTargetMethodSignatureData();
             LocalFunctionStatementSyntax localDllImport = LocalFunctionStatement(returnType, stubTargetName)
                 .AddModifiers(
-                    Token(SyntaxKind.ExternKeyword),
                     Token(SyntaxKind.StaticKeyword),
+                    Token(SyntaxKind.ExternKeyword),
                     Token(SyntaxKind.UnsafeKeyword))
                 .WithSemicolonToken(Token(SyntaxKind.SemicolonToken))
                 .WithAttributeLists(
@@ -516,8 +513,7 @@ private static LocalFunctionStatementSyntax CreateTargetFunctionAsLocalStatement
                                             AttributeArgument(
                                                 NameEquals(nameof(DllImportAttribute.ExactSpelling)),
                                                 null,
-                                                LiteralExpression(
-                                                    libraryImportData.SetLastError ? SyntaxKind.TrueLiteralExpression : SyntaxKind.FalseLiteralExpression))
+                                                LiteralExpression(SyntaxKind.TrueLiteralExpression))
                                         }
                                         )))))))
                 .WithParameterList(parameterList);
@@ -528,7 +524,7 @@ private static LocalFunctionStatementSyntax CreateTargetFunctionAsLocalStatement
             return localDllImport;
         }
 
-        private static AttributeSyntax CreateDllImportAttributeFromLibraryImportAttributeData(LibraryImportData target)
+        private static AttributeSyntax CreateForwarderDllImport(LibraryImportData target)
         {
             var newAttributeArgs = new List<AttributeArgumentSyntax>
             {
@@ -542,7 +538,7 @@ private static AttributeSyntax CreateDllImportAttributeFromLibraryImportAttribut
                 AttributeArgument(
                     NameEquals(nameof(DllImportAttribute.ExactSpelling)),
                     null,
-                    CreateBoolExpressionSyntax(true))
+                    LiteralExpression(SyntaxKind.TrueLiteralExpression))
             };
 
             if (target.IsUserDefined.HasFlag(InteropAttributeMember.StringMarshalling))
@@ -552,6 +548,7 @@ private static AttributeSyntax CreateDllImportAttributeFromLibraryImportAttribut
                 ExpressionSyntax value = CreateEnumExpressionSyntax(CharSet.Unicode);
                 newAttributeArgs.Add(AttributeArgument(name, null, value));
             }
+
             if (target.IsUserDefined.HasFlag(InteropAttributeMember.SetLastError))
             {
                 NameEqualsSyntax name = NameEquals(nameof(DllImportAttribute.SetLastError));

src/libraries/System.Runtime.InteropServices/gen/Microsoft.Interop.SourceGeneration/GeneratedStatements.cs

@@ -71,10 +71,7 @@ private static ImmutableArray<StatementSyntax> GenerateStatementsForStubContext(
             if (statementsToUpdate.Count > 0)
             {
                 // Comment separating each stage
-                SyntaxTriviaList newLeadingTrivia = TriviaList(
-                    Comment($"//"),
-                    Comment($"// {context.CurrentStage}"),
-                    Comment($"//"));
+                SyntaxTriviaList newLeadingTrivia = GenerateStageTrivia(context.CurrentStage);
                 StatementSyntax firstStatementInStage = statementsToUpdate[0];
                 newLeadingTrivia = newLeadingTrivia.AddRange(firstStatementInStage.GetLeadingTrivia());
                 statementsToUpdate[0] = firstStatementInStage.WithLeadingTrivia(newLeadingTrivia);
@@ -108,5 +105,24 @@ private static StatementSyntax GenerateStatementForNativeInvoke(BoundGenerators
                         IdentifierName(context.GetIdentifiers(marshallers.NativeReturnMarshaller.TypeInfo).native),
                         invoke));
         }
+
+        private static SyntaxTriviaList GenerateStageTrivia(StubCodeContext.Stage stage)
+        {
+            string comment = stage switch
+            {
+                StubCodeContext.Stage.Setup => "Perform required setup.",
+                StubCodeContext.Stage.Marshal => "Convert managed data to native data.",
+                StubCodeContext.Stage.Pin => "Pin data in preparation for calling the P/Invoke.",
+                StubCodeContext.Stage.Invoke => "Call the P/Invoke.",
+                StubCodeContext.Stage.Unmarshal => "Convert native data to managed data.",
+                StubCodeContext.Stage.Cleanup => "Perform required cleanup.",
+                StubCodeContext.Stage.KeepAlive => "Keep alive any managed objects that need to stay alive across the call.",
+                StubCodeContext.Stage.GuaranteedUnmarshal => "Convert native data to managed data even in the case of an exception during the non-cleanup phases.",
+                _ => throw new ArgumentOutOfRangeException(nameof(stage))
+            };
+
+            // Comment separating each stage
+            return TriviaList(Comment($"// {stage} - {comment}"));
+        }
     }
 }