Add WASI module to replace Glibc on WASI platform

Author: MaxDesiatov

lib/ClangImporter/ClangImporter.cpp

@@ -461,6 +461,41 @@ getGlibcModuleMapPath(SearchPathOptions& Opts, llvm::Triple triple,
   return None;
 }
 
+static Optional<StringRef>
+getWasiLibcModuleMapPath(SearchPathOptions& Opts, llvm::Triple triple,
+                         SmallVectorImpl<char> &buffer) {
+  StringRef platform = swift::getPlatformNameForTriple(triple);
+  StringRef arch = swift::getMajorArchitectureName(triple);
+
+  if (!Opts.SDKPath.empty()) {
+    buffer.clear();
+    buffer.append(Opts.SDKPath.begin(), Opts.SDKPath.end());
+    llvm::sys::path::append(buffer, "usr", "lib", "swift");
+    llvm::sys::path::append(buffer, platform, arch, "wasi.modulemap");
+
+    // Only specify the module map if that file actually exists.  It may not;
+    // for example in the case that `swiftc -target x86_64-unknown-linux-gnu
+    // -emit-ir` is invoked using a Swift compiler not built for Linux targets.
+    if (llvm::sys::fs::exists(buffer))
+      return StringRef(buffer.data(), buffer.size());
+  }
+
+  if (!Opts.RuntimeResourcePath.empty()) {
+    buffer.clear();
+    buffer.append(Opts.RuntimeResourcePath.begin(),
+                  Opts.RuntimeResourcePath.end());
+    llvm::sys::path::append(buffer, platform, arch, "wasi.modulemap");
+
+    // Only specify the module map if that file actually exists.  It may not;
+    // for example in the case that `swiftc -target x86_64-unknown-linux-gnu
+    // -emit-ir` is invoked using a Swift compiler not built for Linux targets.
+    if (llvm::sys::fs::exists(buffer))
+      return StringRef(buffer.data(), buffer.size());
+  }
+
+  return None;
+}
+
 void
 importer::getNormalInvocationArguments(
     std::vector<std::string> &invocationArgStrs,
@@ -604,6 +639,10 @@ importer::getNormalInvocationArguments(
 
     if (triple.isOSWASI()) {
       invocationArgStrs.insert(invocationArgStrs.end(), {"-D_WASI_EMULATED_MMAN"});
+      SmallString<128> buffer;
+      if (auto path = getWasiLibcModuleMapPath(searchPathOpts, triple, buffer)) {
+        invocationArgStrs.push_back((Twine("-fmodule-map-file=") + *path).str());
+      }
     }
 
     if (triple.isOSWindows()) {

stdlib/private/StdlibUnittest/CMakeLists.txt

@@ -41,7 +41,7 @@ add_swift_target_library(swiftStdlibUnittest ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES}
   SWIFT_MODULE_DEPENDS_OPENBSD Glibc SwiftPrivateThreadExtras
   SWIFT_MODULE_DEPENDS_CYGWIN Glibc SwiftPrivateThreadExtras
   SWIFT_MODULE_DEPENDS_HAIKU Glibc SwiftPrivateThreadExtras
-  SWIFT_MODULE_DEPENDS_WASI Glibc
+  SWIFT_MODULE_DEPENDS_WASI WASILibc
   SWIFT_MODULE_DEPENDS_WINDOWS MSVCRT WinSDK SwiftPrivateThreadExtras
   SWIFT_COMPILE_FLAGS ${swift_stdlib_unittest_compile_flags} ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
   INSTALL_IN_COMPONENT stdlib-experimental

stdlib/private/StdlibUnittest/RaceTest.swift

@@ -45,6 +45,8 @@ import SwiftPrivateThreadExtras
 import Darwin
 #elseif canImport(Glibc)
 import Glibc
+#elseif os(WASI)
+import WASILibc
 #elseif os(Windows)
 import MSVCRT
 import WinSDK

stdlib/private/StdlibUnittest/StdlibCoreExtras.swift

@@ -16,6 +16,8 @@ import SwiftPrivateLibcExtras
 import Darwin
 #elseif canImport(Glibc)
 import Glibc
+#elseif os(WASI)
+import WASILibc
 #elseif os(Windows)
 import MSVCRT
 #endif

stdlib/private/StdlibUnittest/StdlibUnittest.swift

@@ -22,6 +22,8 @@ import Foundation
 import Darwin
 #elseif canImport(Glibc)
 import Glibc
+#elseif os(WASI)
+import WASILibc
 #elseif os(Windows)
 import MSVCRT
 import WinSDK

stdlib/private/StdlibUnittest/SymbolLookup.swift

@@ -14,6 +14,8 @@
   import Darwin
 #elseif canImport(Glibc)
   import Glibc
+#elseif os(WASI)
+  import WASILibc
 #elseif os(Windows)
   import MSVCRT
   import WinSDK

stdlib/private/SwiftPrivateLibcExtras/CMakeLists.txt

@@ -18,7 +18,7 @@ add_swift_target_library(swiftSwiftPrivateLibcExtras ${SWIFT_STDLIB_LIBRARY_BUIL
   SWIFT_MODULE_DEPENDS_OPENBSD Glibc
   SWIFT_MODULE_DEPENDS_CYGWIN Glibc
   SWIFT_MODULE_DEPENDS_HAIKU Glibc
-  SWIFT_MODULE_DEPENDS_WASI Glibc
+  SWIFT_MODULE_DEPENDS_WASI WASILibc
   SWIFT_MODULE_DEPENDS_WINDOWS MSVCRT WinSDK
   INSTALL_IN_COMPONENT stdlib-experimental
   DARWIN_INSTALL_NAME_DIR "${SWIFT_DARWIN_STDLIB_PRIVATE_INSTALL_NAME_DIR}")

stdlib/private/SwiftPrivateLibcExtras/Subprocess.swift

@@ -15,6 +15,8 @@ import SwiftPrivate
 import Darwin
 #elseif canImport(Glibc)
 import Glibc
+#elseif os(WASI)
+import WASILibc
 #elseif os(Windows)
 import MSVCRT
 import WinSDK

stdlib/private/SwiftPrivateLibcExtras/SwiftPrivateLibcExtras.swift

@@ -15,6 +15,8 @@ import SwiftPrivate
 import Darwin
 #elseif canImport(Glibc)
 import Glibc
+#elseif os(WASI)
+import WASILibc
 #elseif os(Windows)
 import MSVCRT
 #endif

stdlib/private/SwiftPrivateThreadExtras/CMakeLists.txt

@@ -15,7 +15,7 @@ add_swift_target_library(swiftSwiftPrivateThreadExtras ${SWIFT_STDLIB_LIBRARY_BU
   SWIFT_MODULE_DEPENDS_OPENBSD Glibc
   SWIFT_MODULE_DEPENDS_CYGWIN Glibc
   SWIFT_MODULE_DEPENDS_HAIKU Glibc
-  SWIFT_MODULE_DEPENDS_WASI Glibc
+  SWIFT_MODULE_DEPENDS_WASI WASILibc
   SWIFT_MODULE_DEPENDS_WINDOWS MSVCRT WinSDK
   SWIFT_COMPILE_FLAGS ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
   TARGET_SDKS ALL_APPLE_PLATFORMS CYGWIN FREEBSD OPENBSD HAIKU LINUX WINDOWS ANDROID