1 files changed, 157 insertions, 0 deletions
diff --git a/clang/include/clang/Basic/DarwinSDKInfo.h b/clang/include/clang/Basic/DarwinSDKInfo.h
new file mode 100644
index 000000000000..918dc7c8becc
--- /dev/null
+++ b/clang/include/clang/Basic/DarwinSDKInfo.h
@@ -0,0 +1,157 @@
+//===--- DarwinSDKInfo.h - SDK Information parser for darwin ----*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_BASIC_DARWIN_SDK_INFO_H
+#define LLVM_CLANG_BASIC_DARWIN_SDK_INFO_H
+
+#include "clang/Basic/LLVM.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/Triple.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/VersionTuple.h"
+#include "llvm/Support/VirtualFileSystem.h"
+
+namespace llvm {
+namespace json {
+class Object;
+} // end namespace json
+} // end namespace llvm
+
+namespace clang {
+
+/// The information about the darwin SDK that was used during this compilation.
+class DarwinSDKInfo {
+public:
+  /// A value that describes two os-environment pairs that can be used as a key
+  /// to the version map in the SDK.
+  struct OSEnvPair {
+  public:
+    using StorageType = uint64_t;
+
+    constexpr OSEnvPair(llvm::Triple::OSType FromOS,
+                        llvm::Triple::EnvironmentType FromEnv,
+                        llvm::Triple::OSType ToOS,
+                        llvm::Triple::EnvironmentType ToEnv)
+        : Value(((StorageType(FromOS) * StorageType(llvm::Triple::LastOSType) +
+                  StorageType(FromEnv))
+                 << 32ull) |
+                (StorageType(ToOS) * StorageType(llvm::Triple::LastOSType) +
+                 StorageType(ToEnv))) {}
+
+    /// Returns the os-environment mapping pair that's used to represent the
+    /// macOS -> Mac Catalyst version mapping.
+    static inline constexpr OSEnvPair macOStoMacCatalystPair() {
+      return OSEnvPair(llvm::Triple::MacOSX, llvm::Triple::UnknownEnvironment,
+                       llvm::Triple::IOS, llvm::Triple::MacABI);
+    }
+
+    /// Returns the os-environment mapping pair that's used to represent the
+    /// Mac Catalyst -> macOS version mapping.
+    static inline constexpr OSEnvPair macCatalystToMacOSPair() {
+      return OSEnvPair(llvm::Triple::IOS, llvm::Triple::MacABI,
+                       llvm::Triple::MacOSX, llvm::Triple::UnknownEnvironment);
+    }
+
+  private:
+    StorageType Value;
+
+    friend class DarwinSDKInfo;
+  };
+
+  /// Represents a version mapping that maps from a version of one target to a
+  /// version of a related target.
+  ///
+  /// e.g. "macOS_iOSMac":{"10.15":"13.1"} is an example of a macOS -> Mac
+  /// Catalyst version map.
+  class RelatedTargetVersionMapping {
+  public:
+    RelatedTargetVersionMapping(
+        VersionTuple MinimumKeyVersion, VersionTuple MaximumKeyVersion,
+        VersionTuple MinimumValue, VersionTuple MaximumValue,
+        llvm::DenseMap<VersionTuple, VersionTuple> Mapping)
+        : MinimumKeyVersion(MinimumKeyVersion),
+          MaximumKeyVersion(MaximumKeyVersion), MinimumValue(MinimumValue),
+          MaximumValue(MaximumValue), Mapping(Mapping) {
+      assert(!this->Mapping.empty() && "unexpected empty mapping");
+    }
+
+    /// Returns the value with the lowest version in the mapping.
+    const VersionTuple &getMinimumValue() const { return MinimumValue; }
+
+    /// Returns the mapped key, or the appropriate Minimum / MaximumValue if
+    /// they key is outside of the mapping bounds. If they key isn't mapped, but
+    /// within the minimum and maximum bounds, None is returned.
+    Optional<VersionTuple> map(const VersionTuple &Key,
+                               const VersionTuple &MinimumValue,
+                               Optional<VersionTuple> MaximumValue) const;
+
+    static Optional<RelatedTargetVersionMapping>
+    parseJSON(const llvm::json::Object &Obj,
+              VersionTuple MaximumDeploymentTarget);
+
+  private:
+    VersionTuple MinimumKeyVersion;
+    VersionTuple MaximumKeyVersion;
+    VersionTuple MinimumValue;
+    VersionTuple MaximumValue;
+    llvm::DenseMap<VersionTuple, VersionTuple> Mapping;
+  };
+
+  DarwinSDKInfo(VersionTuple Version, VersionTuple MaximumDeploymentTarget,
+                llvm::DenseMap<OSEnvPair::StorageType,
+                               Optional<RelatedTargetVersionMapping>>
+                    VersionMappings =
+                        llvm::DenseMap<OSEnvPair::StorageType,
+                                       Optional<RelatedTargetVersionMapping>>())
+      : Version(Version), MaximumDeploymentTarget(MaximumDeploymentTarget),
+        VersionMappings(std::move(VersionMappings)) {}
+
+  const llvm::VersionTuple &getVersion() const { return Version; }
+
+  // Returns the optional, target-specific version mapping that maps from one
+  // target to another target.
+  //
+  // This mapping is constructed from an appropriate mapping in the SDKSettings,
+  // for instance, when building for Mac Catalyst, the mapping would contain the
+  // "macOS_iOSMac" mapping as it maps the macOS versions to the Mac Catalyst
+  // versions.
+  //
+  // This mapping does not exist when the target doesn't have an appropriate
+  // related version mapping, or when there was an error reading the mapping
+  // from the SDKSettings, or when it's missing in the SDKSettings.
+  const RelatedTargetVersionMapping *getVersionMapping(OSEnvPair Kind) const {
+    auto Mapping = VersionMappings.find(Kind.Value);
+    if (Mapping == VersionMappings.end())
+      return nullptr;
+    return Mapping->getSecond().hasValue() ? Mapping->getSecond().getPointer()
+                                           : nullptr;
+  }
+
+  static Optional<DarwinSDKInfo>
+  parseDarwinSDKSettingsJSON(const llvm::json::Object *Obj);
+
+private:
+  VersionTuple Version;
+  VersionTuple MaximumDeploymentTarget;
+  // Need to wrap the value in an optional here as the value has to be default
+  // constructible, and std::unique_ptr doesn't like DarwinSDKInfo being
+  // Optional as Optional is trying to copy it in emplace.
+  llvm::DenseMap<OSEnvPair::StorageType, Optional<RelatedTargetVersionMapping>>
+      VersionMappings;
+};
+
+/// Parse the SDK information from the SDKSettings.json file.
+///
+/// \returns an error if the SDKSettings.json file is invalid, None if the
+/// SDK has no SDKSettings.json, or a valid \c DarwinSDKInfo otherwise.
+Expected<Optional<DarwinSDKInfo>> parseDarwinSDKInfo(llvm::vfs::FileSystem &VFS,
+                                                     StringRef SDKRootPath);
+
+} // end namespace clang
+
+#endif // LLVM_CLANG_BASIC_DARWIN_SDK_INFO_H