Skip to content

Dependencies: handle empty clang trace (rdar://159767983) #771

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 3 commits into from
Sep 3, 2025
Merged

Dependencies: handle empty clang trace (rdar://159767983) #771

Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
8a8e63e
Dependencies: refactor Clang task action dependencies handling to sha…
mirza-garibovic Sep 3, 2025
1f21814
Dependencies: handle empty clang trace
mirza-garibovic Sep 3, 2025
5052d65
Dependencies: annotate clang trace decoding errors with file paths
mirza-garibovic Sep 3, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
153 changes: 86 additions & 67 deletions Sources/SWBTaskExecution/TaskActions/ClangCompileTaskAction.swift
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -337,28 +337,12 @@ public final class ClangCompileTaskAction: TaskAction, BuildValueValidatingTaskA

if lastResult == .succeeded {
// Verify the dependencies from the trace data.
let payload: DependencyValidationInfo.Payload
if let traceFilePath {
let fs = executionDelegate.fs
let traceData = try JSONDecoder().decode(Array<TraceData>.self, from: Data(fs.read(traceFilePath)))

var allFiles = Set<Path>()
traceData.forEach { allFiles.formUnion(Set($0.includes)) }
let (imports, includes) = separateImportsFromIncludes(allFiles)
payload = .clangDependencies(imports: imports, includes: includes)
} else {
payload = .unsupported
}

if let dependencyValidationOutputPath {
let validationInfo = DependencyValidationInfo(payload: payload)
_ = try executionDelegate.fs.writeIfChanged(
dependencyValidationOutputPath,
contents: ByteString(
JSONEncoder(outputFormatting: .sortedKeys).encode(validationInfo)
)
)
}
try Self.handleDependencyValidation(
traceFilePath: traceFilePath,
dependencyValidationOutputPath: dependencyValidationOutputPath,
fileSystem: executionDelegate.fs,
isModular: true
)
}

return lastResult ?? .failed
Expand All @@ -368,30 +352,7 @@ public final class ClangCompileTaskAction: TaskAction, BuildValueValidatingTaskA
}
}

// Clang's dependency tracing does not currently clearly distinguish modular imports from non-modular includes.
// Until that gets fixed, just guess that if the file is contained in a framework, it comes from a module with
// the same name. That is obviously not going to be reliable but it unblocks us from continuing experiments with
// dependency specifications.
private func separateImportsFromIncludes(_ files: Set<Path>) -> ([DependencyValidationInfo.Import], [Path]) {
func findFrameworkName(_ file: Path) -> String? {
if file.fileExtension == "framework" {
return file.basenameWithoutSuffix
}
return file.dirname.isEmpty || file.dirname.isRoot ? nil : findFrameworkName(file.dirname)
}
var moduleNames: [String] = []
var includeFiles: [Path] = []
for file in files {
if let frameworkName = findFrameworkName(file) {
moduleNames.append(frameworkName)
} else {
includeFiles.append(file)
}
}
let moduleDependencies = moduleNames.map { ModuleDependency(name: $0, accessLevel: .Private, optional: false) }
let moduleImports = moduleDependencies.map { DependencyValidationInfo.Import(dependency: $0, importLocations: []) }
return (moduleImports, includeFiles)
}


/// Intended to be called during task dependency setup.
/// If remote caching is enabled along with integrated cache queries, it will request
Expand Down Expand Up @@ -512,6 +473,79 @@ public final class ClangCompileTaskAction: TaskAction, BuildValueValidatingTaskA
activityReporter: dynamicExecutionDelegate
)
}

/// Handles dependency validation by reading trace data and writing out DependencyValidationInfo.
/// This is shared between modular and non-modular compilation tasks.
fileprivate static func handleDependencyValidation(
traceFilePath: Path?,
dependencyValidationOutputPath: Path?,
fileSystem: any FSProxy,
isModular: Bool
) throws {
let payload: DependencyValidationInfo.Payload
if let traceFilePath {
let traceFileContent = try fileSystem.read(traceFilePath)

let traceData: Array<TraceData>
// clang will emit an empty file instead of an empty array when there's nothing to trace
if traceFileContent.isEmpty {
traceData = []
} else {
do {
traceData = try JSONDecoder().decode(Array<TraceData>.self, from: Data(traceFileContent))
} catch {
throw StubError.error("Failed to decode json trace at \(traceFilePath.str): \(error)")
}
}

var allFiles = Set<Path>()
traceData.forEach { allFiles.formUnion(Set($0.includes)) }

if isModular {
let (imports, includes) = separateImportsFromIncludes(allFiles)
payload = .clangDependencies(imports: imports, includes: includes)
} else {
payload = .clangDependencies(imports: [], includes: Array(allFiles))
}
} else {
payload = .unsupported
}

if let dependencyValidationOutputPath {
let validationInfo = DependencyValidationInfo(payload: payload)
_ = try fileSystem.writeIfChanged(
dependencyValidationOutputPath,
contents: ByteString(
JSONEncoder(outputFormatting: .sortedKeys).encode(validationInfo)
)
)
}
}

// Clang's dependency tracing does not currently clearly distinguish modular imports from non-modular includes.
// Until that gets fixed, just guess that if the file is contained in a framework, it comes from a module with
// the same name. That is obviously not going to be reliable but it unblocks us from continuing experiments with
// dependency specifications.
private static func separateImportsFromIncludes(_ files: Set<Path>) -> ([DependencyValidationInfo.Import], [Path]) {
func findFrameworkName(_ file: Path) -> String? {
if file.fileExtension == "framework" {
return file.basenameWithoutSuffix
}
return file.dirname.isEmpty || file.dirname.isRoot ? nil : findFrameworkName(file.dirname)
}
var moduleNames: [String] = []
var includeFiles: [Path] = []
for file in files {
if let frameworkName = findFrameworkName(file) {
moduleNames.append(frameworkName)
} else {
includeFiles.append(file)
}
}
let moduleDependencies = moduleNames.map { ModuleDependency(name: $0, accessLevel: .Private, optional: false) }
let moduleImports = moduleDependencies.map { DependencyValidationInfo.Import(dependency: $0, importLocations: []) }
return (moduleImports, includeFiles)
}
}

public final class ClangNonModularCompileTaskAction: TaskAction {
Expand Down Expand Up @@ -560,27 +594,12 @@ public final class ClangNonModularCompileTaskAction: TaskAction {
let execResult = processDelegate.commandResult ?? .failed

if execResult == .succeeded {
let payload: DependencyValidationInfo.Payload
if let traceFilePath {
let fs = executionDelegate.fs
let traceData = try JSONDecoder().decode(Array<TraceData>.self, from: fs.readMemoryMapped(traceFilePath))

var allFiles = Set<Path>()
traceData.forEach { allFiles.formUnion(Set($0.includes)) }
payload = .clangDependencies(imports: [], includes: Array(allFiles))
} else {
payload = .unsupported
}

if let dependencyValidationOutputPath {
let validationInfo = DependencyValidationInfo(payload: payload)
_ = try executionDelegate.fs.writeIfChanged(
dependencyValidationOutputPath,
contents: ByteString(
JSONEncoder(outputFormatting: .sortedKeys).encode(validationInfo)
)
)
}
try ClangCompileTaskAction.handleDependencyValidation(
traceFilePath: traceFilePath,
dependencyValidationOutputPath: dependencyValidationOutputPath,
fileSystem: executionDelegate.fs,
isModular: false
)
}

return execResult
Expand Down