Revert "Revert "Support macros when cross-compiling (#7118)" (#7352)"

This reverts commit adfbd9a.

CHANGELOG.md

@@ -1,18 +1,29 @@
 Note: This is in reverse chronological order, so newer entries are added to the top.
 
-Swift Next
+Swift 6.0
 -----------
 
 * [#7202]
 
   Package manifests can now access information about the Git repository the given package is in via the context object's 
   `gitInformation` property. This allows to determine the current tag (if any), the current commit and whether or not there are uncommited changes.
 
+* [#7201]
+
+  `// swift-tools-version:` can now be specified on subsequent lines of `Package.swift`, for example when first few lines are required to contain a licensing comment header.
+
+* [#7118]
+
+  Macros cross-compiled by SwiftPM with Swift SDKs are now correctly built, loaded, and evaluated for the host triple.
+
+Swift 5.10
+-----------
+
 * [#7010]
 
   On macOS, `swift build` and `swift run` now produce binaries that allow backtraces in debug builds. Pass `SWIFT_BACKTRACE=enable=yes` environment variable to enable backtraces on such binaries when running them.
 
-* [7101]
+* [#7101]
 
    Binary artifacts are now cached along side repository checkouts so they do not need to be re-downloaded across projects.
 
@@ -387,4 +398,8 @@ Swift 3.0
 [#6276]: /~https://github.com/apple/swift-package-manager/pull/6276
 [#6540]: /~https://github.com/apple/swift-package-manager/pull/6540
 [#6663]: /~https://github.com/apple/swift-package-manager/pull/6663
+[#7010]: /~https://github.com/apple/swift-package-manager/pull/7010
 [#7101]: /~https://github.com/apple/swift-package-manager/pull/7101
+[#7118]: /~https://github.com/apple/swift-package-manager/pull/7118
+[#7201]: /~https://github.com/apple/swift-package-manager/pull/7201
+[#7202]: /~https://github.com/apple/swift-package-manager/pull/7202

Sources/Basics/Collections/IdentifiableSet.swift

@@ -45,13 +45,22 @@ public struct IdentifiableSet<Element: Identifiable>: Collection {
     }
 
     public subscript(id: Element.ID) -> Element? {
-        self.storage[id]
+        get {
+            self.storage[id]
+        }
+        set {
+            self.storage[id] = newValue
+        }
     }
 
     public func index(after i: Index) -> Index {
         Index(storageIndex: self.storage.index(after: i.storageIndex))
     }
 
+    public mutating func insert(_ element: Element) {
+        self.storage[element.id] = element
+    }
+
     public func union(_ otherSequence: some Sequence<Element>) -> Self {
         var result = self
         for element in otherSequence {

Sources/Build/BuildDescription/ClangTargetBuildDescription.swift

@@ -19,6 +19,9 @@ import struct SPMBuildCore.BuildParameters
 import struct SPMBuildCore.BuildToolPluginInvocationResult
 import struct SPMBuildCore.PrebuildCommandResult
 
+@_spi(SwiftPMInternal)
+import SPMBuildCore
+
 import enum TSCBasic.ProcessEnv
 
 /// Target description for a Clang target i.e. C language family target.
@@ -49,7 +52,7 @@ public final class ClangTargetBuildDescription {
 
     /// Path to the bundle generated for this module (if any).
     var bundlePath: AbsolutePath? {
-        guard !resources.isEmpty else {
+        guard !self.resources.isEmpty else {
             return .none
         }
 
@@ -127,7 +130,7 @@ public final class ClangTargetBuildDescription {
         self.target = target
         self.toolsVersion = toolsVersion
         self.buildParameters = buildParameters
-        self.tempsPath = buildParameters.buildPath.appending(component: target.c99name + ".build")
+        self.tempsPath = target.tempsPath(buildParameters)
         self.derivedSources = Sources(paths: [], root: tempsPath.appending("DerivedSources"))
 
         // We did not use to apply package plugins to C-family targets in prior tools-versions, this preserves the behavior.
@@ -219,7 +222,7 @@ public final class ClangTargetBuildDescription {
         if self.buildParameters.triple.isDarwin() {
             args += ["-fobjc-arc"]
         }
-        args += try buildParameters.targetTripleArgs(for: target)
+        args += try self.buildParameters.tripleArgs(for: target)
 
         args += optimizationArguments
         args += activeCompilationConditions

Sources/Build/BuildDescription/ProductBuildDescription.swift

@@ -311,7 +311,7 @@ public final class ProductBuildDescription: SPMBuildCore.ProductBuildDescription
         // setting is the package-level right now. We might need to figure out a better
         // answer for libraries if/when we support specifying deployment target at the
         // target-level.
-        args += try self.buildParameters.targetTripleArgs(for: self.product.targets[self.product.targets.startIndex])
+        args += try self.buildParameters.tripleArgs(for: self.product.targets[self.product.targets.startIndex])
 
         // Add arguments from declared build settings.
         args += self.buildSettingsFlags
@@ -346,7 +346,7 @@ public final class ProductBuildDescription: SPMBuildCore.ProductBuildDescription
         // Library search path for the toolchain's copy of SwiftSyntax.
         #if BUILD_MACROS_AS_DYLIBS
         if product.type == .macro {
-            args += try ["-L", buildParameters.toolchain.hostLibDir.pathString]
+            args += try ["-L", defaultBuildParameters.toolchain.hostLibDir.pathString]
         }
         #endif
 

Sources/Build/BuildDescription/ResolvedTarget+BuildDescription.swift

@@ -0,0 +1,23 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift open source project
+//
+// Copyright (c) 2015-2023 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See http://swift.org/LICENSE.txt for license information
+// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import struct Basics.AbsolutePath
+import struct PackageGraph.ResolvedTarget
+
+@_spi(SwiftPMInternal)
+import SPMBuildCore
+
+extension ResolvedTarget {
+    func tempsPath(_ buildParameters: BuildParameters) -> AbsolutePath {
+        buildParameters.buildPath.appending(component: self.c99name + "\(self.buildTriple.suffix).build")
+    }
+}