Enable wasi-libc emulation features

Those features require explicit macro definitions to be enabled, so add
them to the package definition. Only affects WASI builds.

Author: kateinoigakukun

CMakeLists.txt

@@ -104,6 +104,14 @@ foreach(version ${_SwiftFoundation_versions})
     endforeach()
 endforeach()
 
+# wasi-libc emulation feature flags
+set(_SwiftFoundation_wasi_libc_flags)
+if(CMAKE_SYSTEM_NAME STREQUAL "WASI")
+    list(APPEND _SwiftFoundation_wasi_libc_flags
+        "SHELL:$<$<COMPILE_LANGUAGE:Swift>:-Xcc -D_WASI_EMULATED_SIGNAL>"
+        "SHELL:$<$<COMPILE_LANGUAGE:Swift>:-Xcc -D_WASI_EMULATED_MMAN>")
+endif()
+
 include(GNUInstallDirs)
 include(SwiftFoundationSwiftSupport)
 

Package.swift

@@ -70,6 +70,11 @@ var dependencies: [Package.Dependency] {
     }
 }
 
+let wasiLibcCSettings: [CSetting] = [
+    .define("_WASI_EMULATED_SIGNAL", .when(platforms: [.wasi])),
+    .define("_WASI_EMULATED_MMAN", .when(platforms: [.wasi])),
+]
+
 let package = Package(
     name: "FoundationPreview",
     platforms: [.macOS("13.3"), .iOS("16.4"), .tvOS("16.4"), .watchOS("9.4")],
@@ -88,18 +93,27 @@ let package = Package(
                 "FoundationEssentials",
                 "FoundationInternationalization",
             ],
-            path: "Sources/Foundation"),
+            path: "Sources/Foundation",
+            cSettings: wasiLibcCSettings),
 
         // _FoundationCShims (Internal)
-        .target(name: "_FoundationCShims",
-                cSettings: [.define("_CRT_SECURE_NO_WARNINGS",
-                                    .when(platforms: [.windows]))]),
+        .target(
+            name: "_FoundationCShims",
+            cSettings: [
+                .define("_CRT_SECURE_NO_WARNINGS", .when(platforms: [.windows]))
+            ] + wasiLibcCSettings
+        ),
 
         // TestSupport (Internal)
-        .target(name: "TestSupport", dependencies: [
-            "FoundationEssentials",
-            "FoundationInternationalization",
-        ], swiftSettings: availabilityMacros + concurrencyChecking),
+        .target(
+          name: "TestSupport",
+            dependencies: [
+              "FoundationEssentials",
+              "FoundationInternationalization",
+          ],
+          cSettings: wasiLibcCSettings,
+          swiftSettings: availabilityMacros + concurrencyChecking
+        ),
 
         // FoundationEssentials
         .target(
@@ -130,11 +144,14 @@ let package = Package(
           ],
           cSettings: [
             .define("_GNU_SOURCE", .when(platforms: [.linux]))
-          ],
+          ] + wasiLibcCSettings,
           swiftSettings: [
             .enableExperimentalFeature("VariadicGenerics"),
             .enableExperimentalFeature("AccessLevelOnImport")
-          ] + availabilityMacros + concurrencyChecking
+          ] + availabilityMacros + concurrencyChecking,
+          linkerSettings: [
+            .linkedLibrary("wasi-emulated-getpid", .when(platforms: [.wasi])),
+          ]
         ),
         .testTarget(
             name: "FoundationEssentialsTests",
@@ -166,6 +183,7 @@ let package = Package(
                 "CMakeLists.txt",
                 "Predicate/CMakeLists.txt"
             ],
+            cSettings: wasiLibcCSettings,
             swiftSettings: [
                 .enableExperimentalFeature("AccessLevelOnImport")
             ] + availabilityMacros + concurrencyChecking

Sources/FoundationEssentials/CMakeLists.txt

@@ -66,6 +66,7 @@ target_compile_options(FoundationEssentials PRIVATE
     "SHELL:$<$<COMPILE_LANGUAGE:Swift>:-Xfrontend -enable-experimental-feature -Xfrontend StrictConcurrency>"
     "SHELL:$<$<COMPILE_LANGUAGE:Swift>:-Xfrontend -enable-upcoming-feature -Xfrontend InferSendableFromCaptures>")
 target_compile_options(FoundationEssentials PRIVATE ${_SwiftFoundation_availability_macros})
+target_compile_options(FoundationEssentials PRIVATE ${_SwiftFoundation_wasi_libc_flags})
 target_compile_options(FoundationEssentials PRIVATE -package-name "SwiftFoundation")
 
 target_link_libraries(FoundationEssentials PUBLIC

Sources/FoundationInternationalization/CMakeLists.txt

@@ -33,6 +33,7 @@ target_compile_options(FoundationInternationalization PRIVATE
     "SHELL:$<$<COMPILE_LANGUAGE:Swift>:-Xfrontend -enable-experimental-feature -Xfrontend StrictConcurrency>"
     "SHELL:$<$<COMPILE_LANGUAGE:Swift>:-Xfrontend -enable-upcoming-feature -Xfrontend InferSendableFromCaptures>")
 target_compile_options(FoundationInternationalization PRIVATE ${_SwiftFoundation_availability_macros})
+target_compile_options(FoundationInternationalization PRIVATE ${_SwiftFoundation_wasi_libc_flags})
 target_compile_options(FoundationInternationalization PRIVATE -package-name "SwiftFoundation")
 
 target_link_libraries(FoundationInternationalization PUBLIC

Sources/_FoundationCShims/include/_CStdlib.h

@@ -60,7 +60,17 @@
 #endif
 
 #if __has_include(<signal.h>)
-#include <signal.h>
+/* wasi-libc's signal.h is available only if _WASI_EMULATED_SIGNAL is defined */
+# if !defined(__wasi__) || defined(_WASI_EMULATED_SIGNAL)
+#  include <signal.h>
+# endif
+#endif
+
+#if __has_include(<sys/mman.h>)
+/* wasi-libc's mman.h is available only if _WASI_EMULATED_MMAN is defined */
+# if !defined(__wasi__) || defined(_WASI_EMULATED_MMAN)
+#  include <sys/mman.h>
+# endif
 #endif
 
 #if __has_include(<stdalign.h>)