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[NFC] Move 'InterModuleDependencyGraph' out-of-date analysis into an extension on the graph itself
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4 files changed

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‎Sources/SwiftDriver/ExplicitModuleBuilds/InterModuleDependencies/CommonDependencyOperations.swift

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Original file line numberDiff line numberDiff line change
@@ -11,6 +11,7 @@
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//===----------------------------------------------------------------------===//
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import func TSCBasic.topologicalSort
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import protocol TSCBasic.FileSystem
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@_spi(Testing) public extension InterModuleDependencyGraph {
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/// For targets that are built alongside the driver's current module, the scanning action will report them as
@@ -255,6 +256,82 @@ extension InterModuleDependencyGraph {
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}
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}
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259+
/// Incremental Build Machinery
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internal extension InterModuleDependencyGraph {
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/// We must determine if any of the module dependencies require re-compilation
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/// Since we know that a prior dependency graph was not completely up-to-date,
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/// there must be at least *some* dependencies that require being re-built.
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///
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/// If a dependency is deemed as requiring a re-build, then every module
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/// between it and the root (source module being built by this driver
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/// instance) must also be re-built.
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func computeInvalidatedModuleDependencies(fileSystem: FileSystem,
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reporter: IncrementalCompilationState.Reporter? = nil)
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throws -> Set<ModuleDependencyId> {
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let mainModuleInfo = mainModule
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var modulesRequiringRebuild: Set<ModuleDependencyId> = []
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var visited: Set<ModuleDependencyId> = []
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// Scan from the main module's dependencies to avoid reporting
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// the main module itself in the results.
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for dependencyId in mainModuleInfo.directDependencies ?? [] {
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try outOfDateModuleScan(from: dependencyId, visited: &visited,
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modulesRequiringRebuild: &modulesRequiringRebuild,
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fileSystem: fileSystem, reporter: reporter)
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}
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reporter?.reportExplicitDependencyReBuildSet(Array(modulesRequiringRebuild))
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return modulesRequiringRebuild
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}
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/// Perform a postorder DFS to locate modules which are out-of-date with respect
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/// to their inputs. Upon encountering such a module, add it to the set of invalidated
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/// modules, along with the path from the root to this module.
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func outOfDateModuleScan(from sourceModuleId: ModuleDependencyId,
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visited: inout Set<ModuleDependencyId>,
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modulesRequiringRebuild: inout Set<ModuleDependencyId>,
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fileSystem: FileSystem,
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reporter: IncrementalCompilationState.Reporter? = nil) throws {
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let sourceModuleInfo = try moduleInfo(of: sourceModuleId)
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// Visit the module's dependencies
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var hasOutOfDateModuleDependency = false
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var mostRecentlyUpdatedDependencyOutput: TimePoint = .zero
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for dependencyId in sourceModuleInfo.directDependencies ?? [] {
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// If we have not already visited this module, recurse.
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if !visited.contains(dependencyId) {
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try outOfDateModuleScan(from: dependencyId, visited: &visited,
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modulesRequiringRebuild: &modulesRequiringRebuild,
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fileSystem: fileSystem, reporter: reporter)
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}
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// Even if we're not revisiting a dependency, we must check if it's already known to be out of date.
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hasOutOfDateModuleDependency = hasOutOfDateModuleDependency || modulesRequiringRebuild.contains(dependencyId)
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// Keep track of dependencies' output file time stamp to determine if it is newer than the current module.
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if let depOutputTimeStamp = try? fileSystem.lastModificationTime(for: VirtualPath.lookup(moduleInfo(of: dependencyId).modulePath.path)),
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depOutputTimeStamp > mostRecentlyUpdatedDependencyOutput {
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mostRecentlyUpdatedDependencyOutput = depOutputTimeStamp
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}
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}
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if hasOutOfDateModuleDependency {
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reporter?.reportExplicitDependencyWillBeReBuilt(sourceModuleId.moduleNameForDiagnostic, reason: "Invalidated by downstream dependency")
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modulesRequiringRebuild.insert(sourceModuleId)
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} else if try !IncrementalCompilationState.IncrementalDependencyAndInputSetup.verifyModuleDependencyUpToDate(moduleID: sourceModuleId, moduleInfo: sourceModuleInfo,
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fileSystem: fileSystem, reporter: reporter) {
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reporter?.reportExplicitDependencyWillBeReBuilt(sourceModuleId.moduleNameForDiagnostic, reason: "Out-of-date")
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modulesRequiringRebuild.insert(sourceModuleId)
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} else if let outputModTime = try? fileSystem.lastModificationTime(for: VirtualPath.lookup(sourceModuleInfo.modulePath.path)),
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outputModTime < mostRecentlyUpdatedDependencyOutput {
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// If a prior variant of this module dependnecy exists, and is older than any of its direct or transitive
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// module dependency outputs, it must also be re-built.
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reporter?.reportExplicitDependencyWillBeReBuilt(sourceModuleId.moduleNameForDiagnostic, reason: "Has newer module dependency inputs")
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modulesRequiringRebuild.insert(sourceModuleId)
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}
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// Now that we've determined if this module must be rebuilt, mark it as visited.
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visited.insert(sourceModuleId)
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}
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}
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internal extension InterModuleDependencyGraph {
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func explainDependency(dependencyModuleName: String) throws -> [[ModuleDependencyId]]? {
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guard modules.contains(where: { $0.key.moduleName == dependencyModuleName }) else { return nil }

‎Sources/SwiftDriver/IncrementalCompilation/BuildRecordInfo.swift

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -184,7 +184,7 @@ import class Dispatch.DispatchQueue
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try? fileSystem.removeFileTree(absPath)
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}
186186

187-
func readOutOfDateInterModuleDependencyGraph(
187+
func readPriorInterModuleDependencyGraph(
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reporter: IncrementalCompilationState.Reporter?
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) -> InterModuleDependencyGraph? {
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let decodedGraph: InterModuleDependencyGraph

‎Sources/SwiftDriver/IncrementalCompilation/FirstWaveComputer.swift

Lines changed: 1 addition & 70 deletions
Original file line numberDiff line numberDiff line change
@@ -138,75 +138,6 @@ extension IncrementalCompilationState.FirstWaveComputer {
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mandatoryJobsInOrder: mandatoryJobsInOrder)
139139
}
140140

141-
/// We must determine if any of the module dependencies require re-compilation
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/// Since we know that a prior dependency graph was not completely up-to-date,
143-
/// there must be at least *some* dependencies that require being re-built.
144-
///
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/// If a dependency is deemed as requiring a re-build, then every module
146-
/// between it and the root (source module being built by this driver
147-
/// instance) must also be re-built.
148-
private func computeInvalidatedModuleDependencies(on moduleDependencyGraph: InterModuleDependencyGraph)
149-
throws -> Set<ModuleDependencyId> {
150-
let mainModuleInfo = moduleDependencyGraph.mainModule
151-
var modulesRequiringRebuild: Set<ModuleDependencyId> = []
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var visited: Set<ModuleDependencyId> = []
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// Scan from the main module's dependencies to avoid reporting
154-
// the main module itself in the results.
155-
for dependencyId in mainModuleInfo.directDependencies ?? [] {
156-
try outOfDateModuleScan(on: moduleDependencyGraph, from: dependencyId,
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visited: &visited, modulesRequiringRebuild: &modulesRequiringRebuild)
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}
159-
160-
reporter?.reportExplicitDependencyReBuildSet(Array(modulesRequiringRebuild))
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return modulesRequiringRebuild
162-
}
163-
164-
/// Perform a postorder DFS to locate modules which are out-of-date with respect
165-
/// to their inputs. Upon encountering such a module, add it to the set of invalidated
166-
/// modules, along with the path from the root to this module.
167-
private func outOfDateModuleScan(on moduleDependencyGraph: InterModuleDependencyGraph,
168-
from moduleId: ModuleDependencyId,
169-
visited: inout Set<ModuleDependencyId>,
170-
modulesRequiringRebuild: inout Set<ModuleDependencyId>) throws {
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let moduleInfo = try moduleDependencyGraph.moduleInfo(of: moduleId)
172-
// Visit the module's dependencies
173-
var hasOutOfDateModuleDependency = false
174-
var mostRecentlyUpdatedDependencyOutput: TimePoint = .zero
175-
for dependencyId in moduleInfo.directDependencies ?? [] {
176-
// If we have not already visited this module, recurse.
177-
if !visited.contains(dependencyId) {
178-
try outOfDateModuleScan(on: moduleDependencyGraph, from: dependencyId,
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visited: &visited, modulesRequiringRebuild: &modulesRequiringRebuild)
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}
181-
// Even if we're not revisiting a dependency, we must check if it's already known to be out of date.
182-
hasOutOfDateModuleDependency = hasOutOfDateModuleDependency || modulesRequiringRebuild.contains(dependencyId)
183-
184-
// Keep track of dependencies' output file time stamp to determine if it is newer than the current module.
185-
if let depOutputTimeStamp = try? fileSystem.lastModificationTime(for: VirtualPath.lookup(moduleDependencyGraph.moduleInfo(of: dependencyId).modulePath.path)),
186-
depOutputTimeStamp > mostRecentlyUpdatedDependencyOutput {
187-
mostRecentlyUpdatedDependencyOutput = depOutputTimeStamp
188-
}
189-
}
190-
191-
if hasOutOfDateModuleDependency {
192-
reporter?.reportExplicitDependencyWillBeReBuilt(moduleId.moduleNameForDiagnostic, reason: "Invalidated by downstream dependency")
193-
modulesRequiringRebuild.insert(moduleId)
194-
} else if try !IncrementalCompilationState.IncrementalDependencyAndInputSetup.verifyModuleDependencyUpToDate(moduleID: moduleId, moduleInfo: moduleInfo,
195-
fileSystem: fileSystem, reporter: reporter) {
196-
reporter?.reportExplicitDependencyWillBeReBuilt(moduleId.moduleNameForDiagnostic, reason: "Out-of-date")
197-
modulesRequiringRebuild.insert(moduleId)
198-
} else if let outputModTime = try? fileSystem.lastModificationTime(for: VirtualPath.lookup(moduleInfo.modulePath.path)),
199-
outputModTime < mostRecentlyUpdatedDependencyOutput {
200-
// If a prior variant of this module dependnecy exists, and is older than any of its direct or transitive
201-
// module dependency outputs, it must also be re-built.
202-
reporter?.reportExplicitDependencyWillBeReBuilt(moduleId.moduleNameForDiagnostic, reason: "Has newer module dependency inputs")
203-
modulesRequiringRebuild.insert(moduleId)
204-
}
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206-
// Now that we've determined if this module must be rebuilt, mark it as visited.
207-
visited.insert(moduleId)
208-
}
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210141
/// In an explicit module build, filter out dependency module pre-compilation tasks
211142
/// for modules up-to-date from a prior compile.
212143
private func computeMandatoryBeforeCompilesJobs() throws -> [Job] {
@@ -224,7 +155,7 @@ extension IncrementalCompilationState.FirstWaveComputer {
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225156
// Determine which module pre-build jobs must be re-run
226157
let modulesRequiringReBuild =
227-
try computeInvalidatedModuleDependencies(on: moduleDependencyGraph)
158+
try moduleDependencyGraph.computeInvalidatedModuleDependencies(fileSystem: fileSystem, reporter: reporter)
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229160
// Filter the `.generatePCM` and `.compileModuleFromInterface` jobs for
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// modules which do *not* need re-building.

‎Sources/SwiftDriver/IncrementalCompilation/IncrementalDependencyAndInputSetup.swift

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -106,7 +106,7 @@ extension IncrementalCompilationState.IncrementalDependencyAndInputSetup {
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) throws -> InterModuleDependencyGraph? {
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// Attempt to read a serialized inter-module dependency graph from a prior build
108108
guard let priorInterModuleDependencyGraph =
109-
buildRecordInfo.readOutOfDateInterModuleDependencyGraph(reporter: reporter),
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buildRecordInfo.readPriorInterModuleDependencyGraph(reporter: reporter),
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let priorImports = priorInterModuleDependencyGraph.mainModule.directDependencies?.map({ $0.moduleName }) else {
111111
reporter?.reportExplicitBuildMustReScan("Could not read inter-module dependency graph at \(buildRecordInfo.interModuleDependencyGraphPath)")
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return nil

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