[wasm] Add WASILibc module and its build support

include/swift/AST/DiagnosticsClangImporter.def

@@ -118,8 +118,8 @@ WARNING(nonmutating_without_mutable_fields,none,
 
 ERROR(module_map_not_found, none, "module map file '%0' not found", (StringRef))
 
-WARNING(glibc_not_found, none,
-        "glibc not found for '%0'; C stdlib may be unavailable",
+WARNING(libc_not_found, none,
+        "libc not found for '%0'; C stdlib may be unavailable",
         (StringRef))
 WARNING(libstdcxx_not_found, none,
         "libstdc++ not found for '%0'; C++ stdlib may be unavailable",

lib/ClangImporter/ClangIncludePaths.cpp

@@ -89,18 +89,6 @@ static llvm::Optional<Path> getInjectedModuleMapPath(
   return path;
 }
 
-/// Finds the glibc.modulemap file relative to the provided resource dir.
-///
-/// Note that the module map used for Glibc depends on the target we're
-/// compiling for, and is not included in the resource directory with the other
-/// implicit module maps. It's at {freebsd|linux}/{arch}/glibc.modulemap.
-static llvm::Optional<Path> getGlibcModuleMapPath(
-    SearchPathOptions &Opts, const llvm::Triple &triple,
-    const llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> &vfs) {
-  return getActualModuleMapPath("glibc.modulemap", Opts, triple,
-                                /*isArchSpecific*/ true, vfs);
-}
-
 static llvm::Optional<Path> getLibStdCxxModuleMapPath(
     SearchPathOptions &opts, const llvm::Triple &triple,
     const llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> &vfs) {
@@ -190,19 +178,20 @@ createClangArgs(const ASTContext &ctx, clang::driver::Driver &clangDriver) {
   return clangDriverArgs;
 }
 
-static bool shouldInjectGlibcModulemap(const llvm::Triple &triple) {
+static bool shouldInjectLibcModulemap(const llvm::Triple &triple) {
   return triple.isOSGlibc() || triple.isOSOpenBSD() || triple.isOSFreeBSD() ||
-         triple.isAndroid();
+         triple.isAndroid() || triple.isOSWASI();
 }
 
-static SmallVector<std::pair<std::string, std::string>, 2> getGlibcFileMapping(
-    ASTContext &ctx,
-    const llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> &vfs) {
+static SmallVector<std::pair<std::string, std::string>, 2>
+getLibcFileMapping(ASTContext &ctx, StringRef modulemapFileName,
+                   std::optional<StringRef> maybeHeaderFileName,
+                   const llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> &vfs) {
   const llvm::Triple &triple = ctx.LangOpts.Target;
-  if (!shouldInjectGlibcModulemap(triple))
+  if (!shouldInjectLibcModulemap(triple))
     return {};
 
-  // Extract the Glibc path from Clang driver.
+  // Extract the libc path from Clang driver.
   auto clangDriver = createClangDriver(ctx, vfs);
   auto clangDriverArgs = createClangArgs(ctx, clangDriver);
 
@@ -212,42 +201,47 @@ static SmallVector<std::pair<std::string, std::string>, 2> getGlibcFileMapping(
   clangToolchain.AddClangSystemIncludeArgs(clangDriverArgs, includeArgStrings);
   auto parsedIncludeArgs = parseClangDriverArgs(clangDriver, includeArgStrings);
 
-  // Find the include path that contains Glibc headers. We use three arbitrarily
-  // chosen headers to determine if the include path actually contains Glibc.
+  // Find the include path that contains libc headers. We use three arbitrarily
+  // chosen headers to determine if the include path actually contains libc.
   // Ideally we would check that all of the headers referenced from the
   // modulemap are present.
-  Path glibcDir;
+  Path libcDir;
   if (auto dir = findFirstIncludeDir(
           parsedIncludeArgs, {"inttypes.h", "unistd.h", "stdint.h"}, vfs)) {
-    glibcDir = dir.value();
+    libcDir = dir.value();
   } else {
-    ctx.Diags.diagnose(SourceLoc(), diag::glibc_not_found, triple.str());
+    ctx.Diags.diagnose(SourceLoc(), diag::libc_not_found, triple.str());
     return {};
   }
 
   Path actualModuleMapPath;
-  if (auto path = getGlibcModuleMapPath(ctx.SearchPathOpts, triple, vfs))
+  if (auto path = getActualModuleMapPath(modulemapFileName, ctx.SearchPathOpts,
+                                         triple, /*isArchSpecific*/ true, vfs))
     actualModuleMapPath = path.value();
   else
     // FIXME: Emit a warning of some kind.
     return {};
 
-  // TODO: remove the SwiftGlibc.h header and reference all Glibc headers
-  // directly from the modulemap.
-  Path actualHeaderPath = actualModuleMapPath;
-  llvm::sys::path::remove_filename(actualHeaderPath);
-  llvm::sys::path::append(actualHeaderPath, "SwiftGlibc.h");
-
-  Path injectedModuleMapPath(glibcDir);
+  Path injectedModuleMapPath(libcDir);
   llvm::sys::path::append(injectedModuleMapPath, "module.modulemap");
+  SmallVector<std::pair<std::string, std::string>, 2> vfsMappings{
+      {std::string(injectedModuleMapPath), std::string(actualModuleMapPath)}};
 
-  Path injectedHeaderPath(glibcDir);
-  llvm::sys::path::append(injectedHeaderPath, "SwiftGlibc.h");
+  if (maybeHeaderFileName) {
+    // TODO: remove the SwiftGlibc.h header and reference all Glibc headers
+    // directly from the modulemap.
+    Path actualHeaderPath = actualModuleMapPath;
+    llvm::sys::path::remove_filename(actualHeaderPath);
+    llvm::sys::path::append(actualHeaderPath, maybeHeaderFileName.value());
 
-  return {
-      {std::string(injectedModuleMapPath), std::string(actualModuleMapPath)},
-      {std::string(injectedHeaderPath), std::string(actualHeaderPath)},
-  };
+    Path injectedHeaderPath(libcDir);
+    llvm::sys::path::append(injectedHeaderPath, maybeHeaderFileName.value());
+
+    vfsMappings.push_back(
+        {std::string(injectedHeaderPath), std::string(actualHeaderPath)});
+  }
+
+  return vfsMappings;
 }
 
 static void getLibStdCxxFileMapping(
@@ -518,8 +512,19 @@ ClangInvocationFileMapping swift::getClangInvocationFileMapping(
   ClangInvocationFileMapping result;
   if (!vfs)
     vfs = llvm::vfs::getRealFileSystem();
-  // Android/BSD/Linux Mappings
-  result.redirectedFiles.append(getGlibcFileMapping(ctx, vfs));
+
+  const llvm::Triple &triple = ctx.LangOpts.Target;
+
+  if (triple.isOSWASI()) {
+    // WASI Mappings
+    result.redirectedFiles.append(
+        getLibcFileMapping(ctx, "wasi-libc.modulemap", std::nullopt, vfs));
+  } else {
+    // Android/BSD/Linux Mappings
+    result.redirectedFiles.append(getLibcFileMapping(
+        ctx, "glibc.modulemap", StringRef("SwiftGlibc.h"), vfs));
+  }
+
   if (ctx.LangOpts.EnableCXXInterop)
     getLibStdCxxFileMapping(result, ctx, vfs);
 

stdlib/public/Platform/CMakeLists.txt

@@ -114,6 +114,23 @@ add_swift_target_library(swiftMusl ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_SDK_OV
     TARGET_SDKS MUSL
     INSTALL_IN_COMPONENT sdk-overlay)
 
+add_swift_target_library(swiftWASILibc ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_SDK_OVERLAY
+    ${swift_platform_sources}
+    POSIXError.swift
+
+    GYB_SOURCES
+      ${swift_platform_gyb_sources}
+      WASILibc.swift.gyb
+
+    SWIFT_COMPILE_FLAGS
+      ${SWIFT_RUNTIME_SWIFT_COMPILE_FLAGS}
+      ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
+      ${swift_platform_compile_flags}
+    LINK_FLAGS "${SWIFT_RUNTIME_SWIFT_LINK_FLAGS}"
+    TARGET_SDKS WASI
+    INSTALL_IN_COMPONENT sdk-overlay
+    DEPENDS wasilibc_modulemap)
+
 add_swift_target_library(swiftCRT ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_SDK_OVERLAY
     ucrt.swift
     ${swift_platform_sources}
@@ -234,6 +251,43 @@ add_custom_target(glibc_modulemap DEPENDS ${glibc_modulemap_target_list})
 set_property(TARGET glibc_modulemap PROPERTY FOLDER "Miscellaneous")
 add_dependencies(sdk-overlay glibc_modulemap)
 
+set(wasilibc_modulemap_target_list)
+if("WASI" IN_LIST SWIFT_SDKS)
+  set(wasilibc_modulemap_source "wasi-libc.modulemap")
+  foreach(arch ${SWIFT_SDK_WASI_ARCHITECTURES})
+    set(arch_subdir "${SWIFT_SDK_WASI_LIB_SUBDIR}/${arch}")
+    set(module_dir "${SWIFTLIB_DIR}/${arch_subdir}")
+    set(module_dir_static "${SWIFTSTATICLIB_DIR}/${arch_subdir}")
+
+    add_custom_command_target(
+      copy_wasilibc_modulemap_resource
+      COMMAND
+        "${CMAKE_COMMAND}" "-E" "make_directory" ${module_dir} ${module_dir_static}
+      COMMAND
+        "${CMAKE_COMMAND}" "-E" "copy_if_different"
+          "${CMAKE_CURRENT_SOURCE_DIR}/${wasilibc_modulemap_source}" ${module_dir}
+      COMMAND
+        "${CMAKE_COMMAND}" "-E" "copy_if_different"
+          "${CMAKE_CURRENT_SOURCE_DIR}/${wasilibc_modulemap_source}" ${module_dir_static}
+      OUTPUT ${module_dir}/${wasilibc_modulemap_source} ${module_dir_static}/${wasilibc_modulemap_source}
+      COMMENT "Copying WASILibc modulemap to resource directories")
+    add_dependencies(sdk-overlay ${copy_wasilibc_modulemap_resource})
+    list(APPEND wasilibc_modulemap_target_list ${copy_wasilibc_modulemap_resource})
+
+    swift_install_in_component(FILES "${wasilibc_modulemap_source}"
+                               DESTINATION "lib/swift/${arch_subdir}"
+                               COMPONENT sdk-overlay)
+    if(SWIFT_BUILD_STATIC_STDLIB)
+      swift_install_in_component(FILES "${wasilibc_modulemap_source}"
+                                 DESTINATION "lib/swift_static/${arch_subdir}"
+                                 COMPONENT sdk-overlay)
+    endif()
+  endforeach()
+endif()
+add_custom_target(wasilibc_modulemap DEPENDS ${wasilibc_modulemap_target_list})
+set_property(TARGET wasilibc_modulemap PROPERTY FOLDER "Miscellaneous")
+add_dependencies(sdk-overlay wasilibc_modulemap)
+
 if(WINDOWS IN_LIST SWIFT_SDKS)
   swift_install_in_component(FILES
       ucrt.modulemap

stdlib/public/Platform/WASILibc.swift.gyb

@@ -0,0 +1,159 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2020 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+@_exported import SwiftWASILibc // Clang module
+
+//  Constants defined by <math.h>
+@available(swift, deprecated: 3.0, message: "Please use 'Double.pi' or '.pi' to get the value of correct type and avoid casting.")
+public let M_PI = Double.pi
+
+@available(swift, deprecated: 3.0, message: "Please use 'Double.pi / 2' or '.pi / 2' to get the value of correct type and avoid casting.")
+public let M_PI_2 = Double.pi / 2
+
+@available(swift, deprecated: 3.0, message: "Please use 'Double.pi / 4' or '.pi / 4' to get the value of correct type and avoid casting.")
+public let M_PI_4 = Double.pi / 4
+
+@available(swift, deprecated: 3.0, message: "Please use '2.squareRoot()'.")
+public let M_SQRT2 = 2.squareRoot()
+
+@available(swift, deprecated: 3.0, message: "Please use '0.5.squareRoot()'.")
+public let M_SQRT1_2 = 0.5.squareRoot()
+
+//  Constants defined by <float.h>
+@available(swift, deprecated: 3.0, message: "Please use 'T.radix' to get the radix of a FloatingPoint type 'T'.")
+public let FLT_RADIX = Double.radix
+
+%for type, prefix in [('Float', 'FLT'), ('Double', 'DBL')]:
+//  Where does the 1 come from? C counts the usually-implicit leading
+//  significand bit, but Swift does not. Neither is really right or wrong.
+@available(swift, deprecated: 3.0, message: "Please use '${type}.significandBitCount + 1'.")
+public let ${prefix}_MANT_DIG = ${type}.significandBitCount + 1
+
+//  Where does the 1 come from? C models floating-point numbers as having a
+//  significand in [0.5, 1), but Swift (following IEEE 754) considers the
+//  significand to be in [1, 2). This rationale applies to ${prefix}_MIN_EXP
+//  as well.
+@available(swift, deprecated: 3.0, message: "Please use '${type}.greatestFiniteMagnitude.exponent + 1'.")
+public let ${prefix}_MAX_EXP = ${type}.greatestFiniteMagnitude.exponent + 1
+
+@available(swift, deprecated: 3.0, message: "Please use '${type}.leastNormalMagnitude.exponent + 1'.")
+public let ${prefix}_MIN_EXP = ${type}.leastNormalMagnitude.exponent + 1
+
+@available(swift, deprecated: 3.0, message: "Please use '${type}.greatestFiniteMagnitude' or '.greatestFiniteMagnitude'.")
+public let ${prefix}_MAX = ${type}.greatestFiniteMagnitude
+
+@available(swift, deprecated: 3.0, message: "Please use '${type}.ulpOfOne' or '.ulpOfOne'.")
+public let ${prefix}_EPSILON = ${type}.ulpOfOne
+
+@available(swift, deprecated: 3.0, message: "Please use '${type}.leastNormalMagnitude' or '.leastNormalMagnitude'.")
+public let ${prefix}_MIN = ${type}.leastNormalMagnitude
+
+@available(swift, deprecated: 3.0, message: "Please use '${type}.leastNonzeroMagnitude' or '.leastNonzeroMagnitude'.")
+public let ${prefix}_TRUE_MIN = ${type}.leastNonzeroMagnitude
+
+%end
+
+public let MAP_FAILED: UnsafeMutableRawPointer! = UnsafeMutableRawPointer(bitPattern: -1)
+
+// NOTE: wasi-libc's error.h defines these macros as function-like macros, which ClangImporter can't import for now.
+%{
+posix_error_codes = [
+  "E2BIG",
+  "EACCES",
+  "EADDRINUSE",
+  "EADDRNOTAVAIL",
+  "EAFNOSUPPORT",
+  "EAGAIN",
+  "EALREADY",
+  "EBADF",
+  "EBADMSG",
+  "EBUSY",
+  "ECANCELED",
+  "ECHILD",
+  "ECONNABORTED",
+  "ECONNREFUSED",
+  "ECONNRESET",
+  "EDEADLK",
+  "EDESTADDRREQ",
+  "EDOM",
+  "EDQUOT",
+  "EEXIST",
+  "EFAULT",
+  "EFBIG",
+  "EHOSTUNREACH",
+  "EIDRM",
+  "EILSEQ",
+  "EINPROGRESS",
+  "EINTR",
+  "EINVAL",
+  "EIO",
+  "EISCONN",
+  "EISDIR",
+  "ELOOP",
+  "EMFILE",
+  "EMLINK",
+  "EMSGSIZE",
+  "EMULTIHOP",
+  "ENAMETOOLONG",
+  "ENETDOWN",
+  "ENETRESET",
+  "ENETUNREACH",
+  "ENFILE",
+  "ENOBUFS",
+  "ENODEV",
+  "ENOENT",
+  "ENOEXEC",
+  "ENOLCK",
+  "ENOLINK",
+  "ENOMEM",
+  "ENOMSG",
+  "ENOPROTOOPT",
+  "ENOSPC",
+  "ENOSYS",
+  "ENOTCONN",
+  "ENOTDIR",
+  "ENOTEMPTY",
+  "ENOTRECOVERABLE",
+  "ENOTSOCK",
+  "ENOTSUP",
+  "ENOTTY",
+  "ENXIO",
+  "EOVERFLOW",
+  "EOWNERDEAD",
+  "EPERM",
+  "EPIPE",
+  "EPROTO",
+  "EPROTONOSUPPORT",
+  "EPROTOTYPE",
+  "ERANGE",
+  "EROFS",
+  "ESPIPE",
+  "ESRCH",
+  "ESTALE",
+  "ETIMEDOUT",
+  "ETXTBSY",
+  "EXDEV",
+  "ENOTCAPABLE",
+]
+}%
+
+%for ecode in posix_error_codes:
+
+public let ${ecode} = POSIXErrorCode.${ecode}.rawValue
+
+%end
+
+// NOTE: wasi-libc's _seek.h defines these macros as function-like macros, which ClangImporter can't import for now.
+
+public let SEEK_SET: Int32 = 0
+public let SEEK_CUR: Int32 = 1
+public let SEEK_END: Int32 = 2