Align with the original Demangler & NodePrinter #15

Mx-Iris · 2025-06-25T16:54:11Z

No description provided.

Copilot

Pull Request Overview

This PR refactors several components to better align the demangling behavior with the original Demangler and NodePrinter while streamlining test implementations and module integrations.

Updated tests to use a unified symbol collection and revised assertions.
Refactored Demangler logic (including control flow and node handling) and updated NodePrinter output messaging.
Integrated the new MachOSymbols module across relevant components and updated API access levels.

Reviewed Changes

Copilot reviewed 15 out of 19 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
Tests/MachOSwiftSectionTests/SymbolDemangleTests.swift	Revised async behavior, symbol collection and assertion logic; a potential typo in a variable name was introduced.
Tests/MachOSwiftSectionTests/SwiftStdlibDemangle.swift	Added new demangling functions for Swift standard library symbols.
Tests/MachOSwiftSectionTests/MetadataFinderTests.swift	Removed unused machOFile variables and updated test targets.
Sources/MachOTestingSupport/MachOImageName.swift	Added new image name case (Combine).
Sources/MachOSymbols/MachOSymbolCache.swift	Updated API access and adjusted symbol filtering using the new Swift symbol check.
Sources/MachOPointer/*	Updated imports to include MachOSymbols.
Sources/MachOFoundation/Exported.swift	Included MachOSymbols in the exported modules.
Sources/Demangle/*	Refactored several demangling functions (getLabel, popTuple, keyPath handling, etc.) and updated node printing logic.
Sources/Demangle/Main/Node.swift & Node+Kind.swift	Added new methods (reverseFirst) and extended node kinds with keyPath thunk helpers.
Package.swift	Added MachOSymbols as a target dependency where needed.

Copilot · 2025-06-25T16:54:54Z

Tests/MachOSwiftSectionTests/SymbolDemangleTests.swift

+                let swiftSectionDemanlgedName = node.print()
+                #expect(swiftStdlibDemangledName == swiftSectionDemanlgedName, "\(symbol.stringValue)")


The variable name 'swiftSectionDemanlgedName' appears to contain a typo. Consider renaming it to 'swiftSectionDemangledName' to improve clarity.

Suggested change

let swiftSectionDemanlgedName = node.print()

#expect(swiftStdlibDemangledName == swiftSectionDemanlgedName, "\(symbol.stringValue)")

let swiftSectionDemangledName = node.print()

#expect(swiftStdlibDemangledName == swiftSectionDemangledName, "\(symbol.stringValue)")

gemini-code-assist

Summary of Changes

Hello @Mx-Iris, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request aims to improve the accuracy and capabilities of our Swift demangling and node printing components by bringing them into closer alignment with the official Swift compiler's implementation. It involves introducing a new module for Swift symbol management, applying several critical fixes and enhancements to the demangling logic, refining the output formatting, and bolstering the testing framework to ensure correctness.

Highlights

New Module Introduction: I've introduced a new MachOSymbols module to centralize the handling of Swift symbols within Mach-O files. This module is now a dependency for MachOPointer and is re-exported through MachOFoundation, streamlining symbol lookup and integration.
Demangler Accuracy and Feature Alignment: I've made numerous fixes and updates to the Demangler to align its behavior more closely with the original Swift compiler's demangling logic. This includes improved handling of substitutions, function type parameters, new key path types, and a critical fix for Unicode Punycode decoding, ensuring more accurate demangling of complex Swift symbols.
NodePrinter Refinements: The NodePrinter has been refined to correctly reflect the structural changes in the demangled nodes. This ensures that the human-readable output of demangled Swift symbols is accurate and consistent with the updated demangling logic, including new key path types and corrected formatting for various symbol kinds.
Optimized Symbol Caching: The MachOSymbolCache has been refactored to specifically filter and cache only Swift symbols. This change, leveraging a new isSwiftSymbol utility, improves the efficiency and relevance of the symbol cache by focusing on the symbols pertinent to Swift demangling.
Enhanced Testing and Validation: I've significantly enhanced the testing infrastructure by adding utilities to compare our demangler's output directly against the Swift standard library's demangler. This rigorous validation ensures that the changes made accurately reflect the official demangling behavior, improving the reliability of our demangling process.

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gemini-code-assist

Code Review

This pull request significantly enhances the Swift demangling and symbol handling capabilities by aligning the custom demangler and node printer with the original Swift compiler's behavior. Key improvements include numerous correctness fixes in Demangler.swift and NodePrinter.swift for handling various mangling patterns and node structures. The introduction of a new MachOSymbols module and comprehensive testing against the Swift standard library's demangler are major steps forward in ensuring accuracy and reliability. The changes also bring minor efficiency and maintainability improvements through code refactoring and clearer logic.

gemini-code-assist · 2025-06-25T16:56:58Z

Sources/Demangle/Main/NodePrinter.swift

+            genSig = name.children.at(1)
+            type = name.children.at(2)
        } else {
-            type = name.children[0]
+            type = name.children.at(1)


Adjusting the child indices (at(1) and at(2)) for genSig and type in printExtendedExistentialTypeShape is a correctness fix. This aligns the NodePrinter with the expected structure of the extendedExistentialTypeShape node, ensuring the correct components are extracted and printed. The use of at(index) is also safer than direct array access.

if name.children.count == 2 { genSig = name.children.at(1) type = name.children.at(2) } else { type = name.children.at(1) }

gemini-code-assist · 2025-06-25T16:56:58Z

Sources/Demangle/Main/NodePrinter.swift

+             .keyPathSetterThunkHelper,
+             .keyPathAppliedMethodThunkHelper,
+             .keyPathUnappliedMethodThunkHelper: printKeyPathAccessorThunkHelper(name)


Adding the new keyPathAppliedMethodThunkHelper and keyPathUnappliedMethodThunkHelper cases to printKeyPathAccessorThunkHelper ensures that these new key path kinds are correctly handled and printed, aligning with the demangler's expanded capabilities.

case .keyPathGetterThunkHelper, .keyPathSetterThunkHelper, .keyPathAppliedMethodThunkHelper, .keyPathUnappliedMethodThunkHelper: printKeyPathAccessorThunkHelper(name)

gemini-code-assist · 2025-06-25T16:56:59Z

Tests/MachOSwiftSectionTests/SymbolDemangleTests.swift

+    @Test func symbols() throws {
+        let allSwiftSymbols = try allSymbols()
+        print("Total Swift Symbols: \(allSwiftSymbols.count)")
+        for symbol in allSwiftSymbols {
+            let swiftStdlibDemangledName = stdlib_demangleName(symbol.stringValue)
            do {
-                var demangler = Demangler(scalars: symbol.name.unicodeScalars)
-                _ = try demangler.demangleSymbol()
-//                print("Successfully: \(symbol.name)")
+                guard !symbol.stringValue.hasSuffix("$delayInitStub") else { continue }
+                var demangler = Demangler(scalars: symbol.stringValue.unicodeScalars)
+                let node = try demangler.demangleSymbol()
+                let swiftSectionDemanlgedName = node.print()
+                #expect(swiftStdlibDemangledName == swiftSectionDemanlgedName, "\(symbol.stringValue)")
            } catch {
-                print("Failed: \(symbol.name)")
+                #expect(symbol.stringValue == swiftStdlibDemangledName)
+                print(symbol)
                print(error)
-                print("\n")
            }
        }


This refactoring of the symbols() test is a significant improvement in testing rigor. By iterating through all Swift symbols and comparing the output of the custom demangler with the Swift standard library's demangler, it provides strong validation of correctness. The use of #expect with custom messages is excellent for pinpointing failures. The guard !symbol.stringValue.hasSuffix("$delayInitStub") indicates a specific known case that is being skipped, which is good for transparency.

Suggested change

@Test func symbols() throws {

let allSwiftSymbols = try allSymbols()

print("Total Swift Symbols: \(allSwiftSymbols.count)")

for symbol in allSwiftSymbols {

let swiftStdlibDemangledName = stdlib_demangleName(symbol.stringValue)

do {

var demangler = Demangler(scalars: symbol.name.unicodeScalars)

_ = try demangler.demangleSymbol()

// print("Successfully: \(symbol.name)")

guard !symbol.stringValue.hasSuffix("$delayInitStub") else { continue }

var demangler = Demangler(scalars: symbol.stringValue.unicodeScalars)

let node = try demangler.demangleSymbol()

let swiftSectionDemanlgedName = node.print()

#expect(swiftStdlibDemangledName == swiftSectionDemanlgedName, "\(symbol.stringValue)")

} catch {

print("Failed: \(symbol.name)")

#expect(symbol.stringValue == swiftStdlibDemangledName)

print(symbol)

print(error)

print("\n")

}

}

@MainActor

@Test func symbols() throws {

let allSwiftSymbols = try allSymbols()

print("Total Swift Symbols: \(allSwiftSymbols.count)")

for symbol in allSwiftSymbols {

let swiftStdlibDemangledName = stdlib_demangleName(symbol.stringValue)

do {

guard !symbol.stringValue.hasSuffix("$delayInitStub") else { continue }

var demangler = Demangler(scalars: symbol.stringValue.unicodeScalars)

let node = try demangler.demangleSymbol()

let swiftSectionDemanlgedName = node.print()

#expect(swiftStdlibDemangledName == swiftSectionDemanlgedName, "\(symbol.stringValue)")

} catch {

#expect(symbol.stringValue == swiftStdlibDemangledName)

print(symbol)

print(error)

}

}

}

gemini-code-assist · 2025-06-25T16:56:59Z

Sources/Demangle/Main/Demangler.swift

+//        (0 ..< max(0, repeatCount - 1)).forEach { _ in  }
+        var repeatCount = repeatCount
+        while repeatCount > 1 {
+            nameStack.append(nd)
+            repeatCount -= 1
+        }


The change from forEach to a while loop is functionally equivalent and can be slightly more explicit about the decrementing repeatCount. This is a minor improvement in clarity.

var repeatCount = repeatCount while repeatCount > 1 { nameStack.append(nd) repeatCount -= 1 }

gemini-code-assist · 2025-06-25T16:56:59Z

Tests/MachOSwiftSectionTests/MetadataFinderTests.swift

    init() throws {
-        // Cache
        self.mainCache = try DyldCache(path: .current)
-        self.subCache = try required(mainCache.subCaches?.first?.subcache(for: mainCache))
-
-        self.machOFileInMainCache = try #require(mainCache.machOFile(named: .SwiftUI))
-        self.machOFileInSubCache = if #available(macOS 15.5, *) {
-            try #require(subCache.machOFile(named: .CodableSwiftUI))
-        } else {
-            try #require(subCache.machOFile(named: .UIKitCore))
-        }
-
-        self.machOFileInCache = try #require(mainCache.machOFile(named: .AttributeGraph))
-
-        // File
-        let file = try loadFromFile(named: .Finder)
-        switch file {
-        case .fat(let fatFile):
-            self.machOFile = try #require(fatFile.machOFiles().first(where: { $0.header.cpu.type == .arm64 }))
-        case .machO(let machO):
-            self.machOFile = machO
-        @unknown default:
-            fatalError()
-        }
-
-        // Image
-        self.machOImage = try #require(MachOImage(named: .Foundation))
    }

-    @Test func dumpMetadatasInMainCache() async throws {
-        try await dumpMetadatas(for: machOFileInMainCache)
+    @Test func dumpMetadatasInAppKit() async throws {
+        try await dumpMetadatas(for: #require(mainCache.machOFile(named: .AppKit)))
    }

+    @Test func dumpMetadatasInSwiftUI() async throws {
+        try await dumpMetadatas(for: #require(mainCache.machOFile(named: .SwiftUI)))
+    }


Simplifying the test setup by removing numerous machOFile properties and related initialization code makes the test suite more focused and easier to understand. This improves maintainability and reduces boilerplate.

Mx-Iris added 7 commits June 24, 2025 17:45

Align with the original NodePrinter

d45b34a

Align with the original Demangler & NodePrinter

8f4eed2

Update Testing

ff94983

Align with the original Demangler & NodePrinter

a5eedfc

Update Testing

97c7411

Make MachOSymbols target

4ee550c

Align with the original Demangler & NodePrinter

16b887a

Mx-Iris requested a review from Copilot June 25, 2025 16:54

Copilot AI reviewed Jun 25, 2025

View reviewed changes

gemini-code-assist bot reviewed Jun 25, 2025

View reviewed changes

Mx-Iris merged commit 93d1591 into main Jun 26, 2025
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Align with the original Demangler & NodePrinter #15

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		let swiftSectionDemanlgedName = node.print()
		#expect(swiftStdlibDemangledName == swiftSectionDemanlgedName, "\(symbol.stringValue)")

Align with the original Demangler & NodePrinter #15

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Mx-Iris commented Jun 25, 2025

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Pull Request Overview

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