precompute supported scanner-prefix-map option type before initializing ExplicitDependencyBuildPlanner

Author: sina-mahdavi

Sources/SwiftDriver/ExplicitModuleBuilds/ExplicitDependencyBuildPlanner.swift

@@ -63,6 +63,9 @@ public typealias ExternalTargetModuleDetailsMap = [ModuleDependencyId: ExternalT
   /// Does this compile support `.explicitInterfaceModuleBuild`
   private let supportsExplicitInterfaceBuild: Bool
 
+  /// status of the scanner prefix mapping option supported by the frontend
+  private let supportsScannerPrefixMapPaths: Bool
+
   /// Cached command-line additions for all main module compile jobs
   private struct ResolvedModuleDependenciesCommandLineComponents {
     let inputs: [TypedVirtualPath]
@@ -89,14 +92,16 @@ public typealias ExternalTargetModuleDetailsMap = [ModuleDependencyId: ExternalT
               supportsExplicitInterfaceBuild: Bool = false,
               cas: SwiftScanCAS? = nil,
               prefixMap:  [(AbsolutePath, AbsolutePath)] = [],
-              supportsBridgingHeaderPCHCommand: Bool = false) throws {
+              supportsBridgingHeaderPCHCommand: Bool = false,
+              supportsScannerPrefixMapPaths: Bool = false) throws {
     self.dependencyGraph = dependencyGraph
     self.toolchain = toolchain
     self.integratedDriver = integratedDriver
     self.mainModuleName = dependencyGraph.mainModuleName
     self.reachabilityMap = try dependencyGraph.computeTransitiveClosure()
     self.supportsExplicitInterfaceBuild = supportsExplicitInterfaceBuild
     self.supportsBridgingHeaderPCHCommand = supportsBridgingHeaderPCHCommand
+    self.supportsScannerPrefixMapPaths = supportsScannerPrefixMapPaths
     self.cas = cas
     self.prefixMap = prefixMap
     let mainModuleId: ModuleDependencyId = .swift(dependencyGraph.mainModuleName)
@@ -217,7 +222,7 @@ public typealias ExternalTargetModuleDetailsMap = [ModuleDependencyId: ExternalT
       // Add prefix mapping. The option is cache invariant so it can be added without affecting cache key.
       for (key, value) in prefixMap {
         commandLine.appendFlag("-cache-replay-prefix-map")
-        if driver.isFrontendArgSupported(Option.scannerPrefixMapPaths) {
+        if supportsScannerPrefixMapPaths {
           commandLine.appendFlag(value.pathString)
           commandLine.appendFlag(key.pathString)
         } else {
@@ -283,7 +288,7 @@ public typealias ExternalTargetModuleDetailsMap = [ModuleDependencyId: ExternalT
       // Add prefix mapping. The option is cache invariant so it can be added without affecting cache key.
       for (key, value) in prefixMap {
         commandLine.appendFlag("-cache-replay-prefix-map")
-        if driver.isFrontendArgSupported(Option.scannerPrefixMapPaths) {
+        if supportsScannerPrefixMapPaths {
           commandLine.appendFlag(value.pathString)
           commandLine.appendFlag(key.pathString)
         } else {

Sources/SwiftDriver/Jobs/Planning.swift

@@ -122,7 +122,9 @@ extension Driver {
                                                 cas: cas,
                                                 prefixMap: prefixMapping,
                                                 supportsBridgingHeaderPCHCommand:
-                                                  interModuleDependencyOracle.supportsBridgingHeaderPCHCommand)
+                                                  interModuleDependencyOracle.supportsBridgingHeaderPCHCommand,
+                                                supportsScannerPrefixMapPaths:
+                                                  isFrontendArgSupported(.scannerPrefixMapPaths))
     } else {
       return nil
     }

Tests/SwiftDriverTests/ExplicitModuleBuildTests.swift

@@ -174,7 +174,8 @@ final class ExplicitModuleBuildTests: XCTestCase {
               from: ModuleDependenciesInputs.fastDependencyScannerOutput.data(using: .utf8)!)
       var explicitDependencyBuildPlanner =
         try ExplicitDependencyBuildPlanner(dependencyGraph: moduleDependencyGraph,
-                                           toolchain: driver.toolchain)
+                                           toolchain: driver.toolchain,
+                                           supportsScannerPrefixMapPaths: driver.isFrontendArgSupported(.scannerPrefixMapPaths))
       let modulePrebuildJobs =
         try explicitDependencyBuildPlanner.generateExplicitModuleDependenciesBuildJobs(driver: driver)
       XCTAssertEqual(modulePrebuildJobs.count, 4)