Fix checkSupportedFrontendFlags (#6192)

Since this is querying a concrete compiler, it needs to receive the `Toolchain` object from the context in order to query the right one.

Author: neonichu

Package.swift

@@ -326,7 +326,8 @@ let package = Package(
         .target(
             name: "DriverSupport",
             dependencies: [
-		"Basics",
+                "Basics",
+                "PackageModel",
                 .product(name: "SwiftDriver", package: "swift-driver"),
             ],
             exclude: ["CMakeLists.txt"]

Sources/Build/BuildOperation.swift

@@ -171,7 +171,7 @@ public final class BuildOperation: PackageStructureDelegate, SPMBuildCore.BuildS
             return
         }
         // Ensure the compiler supports the import-scan operation
-        guard DriverSupport.checkSupportedFrontendFlags(flags: ["import-prescan"], fileSystem: localFileSystem) else {
+        guard DriverSupport.checkSupportedFrontendFlags(flags: ["import-prescan"], toolchain: self.buildParameters.toolchain, fileSystem: localFileSystem) else {
             return
         }
 

Sources/Commands/Utilities/SymbolGraphExtract.swift

@@ -75,7 +75,7 @@ public struct SymbolGraphExtract {
         }
 
         let extensionBlockSymbolsFlag = emitExtensionBlockSymbols ? "-emit-extension-block-symbols" : "-omit-extension-block-symbols"
-        if DriverSupport.checkSupportedFrontendFlags(flags: [extensionBlockSymbolsFlag.trimmingCharacters(in: ["-"])], fileSystem: fileSystem) {
+        if DriverSupport.checkSupportedFrontendFlags(flags: [extensionBlockSymbolsFlag.trimmingCharacters(in: ["-"])], toolchain: buildParameters.toolchain, fileSystem: fileSystem) {
             commandLine += [extensionBlockSymbolsFlag]
         } else {
             observabilityScope.emit(warning: "dropped \(extensionBlockSymbolsFlag) flag because it is not supported by this compiler version")

Sources/CoreCommands/SwiftTool.swift

@@ -624,7 +624,7 @@ public final class SwiftTool {
                 workers: options.build.jobs ?? UInt32(ProcessInfo.processInfo.activeProcessorCount),
                 shouldLinkStaticSwiftStdlib: options.linker.shouldLinkStaticSwiftStdlib,
                 canRenameEntrypointFunctionName: DriverSupport.checkSupportedFrontendFlags(
-                    flags: ["entry-point-function-name"], fileSystem: self.fileSystem
+                    flags: ["entry-point-function-name"], toolchain: destinationToolchain, fileSystem: self.fileSystem
                 ),
                 sanitizers: options.build.enabledSanitizers,
                 enableCodeCoverage: false, // set by test commands when appropriate
@@ -718,11 +718,11 @@ public final class SwiftTool {
 
             var extraManifestFlags = self.options.build.manifestFlags
             // Disable the implicit concurrency import if the compiler in use supports it to avoid warnings if we are building against an older SDK that does not contain a Concurrency module.
-            if DriverSupport.checkSupportedFrontendFlags(flags: ["disable-implicit-concurrency-module-import"], fileSystem: self.fileSystem) {
+            if DriverSupport.checkSupportedFrontendFlags(flags: ["disable-implicit-concurrency-module-import"], toolchain: try self.buildParameters().toolchain, fileSystem: self.fileSystem) {
                 extraManifestFlags += ["-Xfrontend", "-disable-implicit-concurrency-module-import"]
             }
             // Disable the implicit string processing import if the compiler in use supports it to avoid warnings if we are building against an older SDK that does not contain a StringProcessing module.
-            if DriverSupport.checkSupportedFrontendFlags(flags: ["disable-implicit-string-processing-module-import"], fileSystem: self.fileSystem) {
+            if DriverSupport.checkSupportedFrontendFlags(flags: ["disable-implicit-string-processing-module-import"], toolchain: try self.buildParameters().toolchain, fileSystem: self.fileSystem) {
                 extraManifestFlags += ["-Xfrontend", "-disable-implicit-string-processing-module-import"]
             }
 

Sources/DriverSupport/CMakeLists.txt

@@ -14,6 +14,7 @@ set_target_properties(DriverSupport PROPERTIES
   INTERFACE_INCLUDE_DIRECTORIES ${CMAKE_Swift_MODULE_DIRECTORY})
 target_link_libraries(DriverSupport PUBLIC
   Basics
+  PackageModel
   SwiftDriver)
 
 if(USE_CMAKE_INSTALL)

Sources/DriverSupport/DriverSupportUtils.swift

@@ -12,6 +12,7 @@
 
 import SwiftDriver
 import Basics
+import PackageModel
 import class TSCBasic.Process
 import enum TSCBasic.ProcessEnv
 import struct TSCBasic.ProcessResult
@@ -22,10 +23,10 @@ public class DriverSupport {
     public init() {}
 
     // This checks supported _frontend_ flags, which are not necessarily supported in the driver.
-    public static func checkSupportedFrontendFlags(flags: Set<String>, fileSystem: FileSystem) -> Bool {
+    public static func checkSupportedFrontendFlags(flags: Set<String>, toolchain: PackageModel.Toolchain, fileSystem: FileSystem) -> Bool {
         do {
             let executor = try SPMSwiftDriverExecutor(resolver: ArgsResolver(fileSystem: fileSystem), fileSystem: fileSystem, env: [:])
-            let driver = try Driver(args: ["swiftc"], executor: executor)
+            let driver = try Driver(args: ["swiftc"], executor: executor, compilerExecutableDir: toolchain.swiftCompilerPath.parentDirectory)
             return driver.supportedFrontendFlags.intersection(flags) == flags
         } catch {
             return false

Tests/CommandsTests/APIDiffTests.swift

@@ -53,7 +53,7 @@ final class APIDiffTests: CommandsTestCase {
       // not all of which can be tested for easily. Fortunately, we can test for the
       // `-disable-fail-on-error` option, and any version which supports this flag
       // will meet the other requirements.
-      guard DriverSupport.checkSupportedFrontendFlags(flags: ["disable-fail-on-error"], fileSystem: localFileSystem) else {
+      guard DriverSupport.checkSupportedFrontendFlags(flags: ["disable-fail-on-error"], toolchain: try UserToolchain.default, fileSystem: localFileSystem) else {
         throw XCTSkip("swift-api-digester is too old")
       }
     }