vendor/lld/lld-release_39-r276489

1 files changed, 128 insertions, 0 deletions

diff --git a/lib/ReaderWriter/MachO/ObjCPass.cpp b/lib/ReaderWriter/MachO/ObjCPass.cpp
new file mode 100644
index 000000000000..ba24b3fecdf4
--- /dev/null
+++ b/lib/ReaderWriter/MachO/ObjCPass.cpp
@@ -0,0 +1,128 @@
+//===- lib/ReaderWriter/MachO/ObjCPass.cpp -------------------------------===//
+//
+//                             The LLVM Linker
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//===----------------------------------------------------------------------===//
+
+#include "ArchHandler.h"
+#include "File.h"
+#include "MachOPasses.h"
+#include "lld/Core/DefinedAtom.h"
+#include "lld/Core/File.h"
+#include "lld/Core/LLVM.h"
+#include "lld/Core/Reference.h"
+#include "lld/Core/Simple.h"
+#include "lld/ReaderWriter/MachOLinkingContext.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/STLExtras.h"
+
+namespace lld {
+namespace mach_o {
+
+///
+/// ObjC Image Info Atom created by the ObjC pass.
+///
+class ObjCImageInfoAtom : public SimpleDefinedAtom {
+public:
+  ObjCImageInfoAtom(const File &file,
+                    MachOLinkingContext::ObjCConstraint objCConstraint,
+                    uint32_t swiftVersion)
+      : SimpleDefinedAtom(file) {
+
+    Data.info.version = 0;
+
+    switch (objCConstraint) {
+    case MachOLinkingContext::objc_unknown:
+      llvm_unreachable("Shouldn't run the objc pass without a constraint");
+    case MachOLinkingContext::objc_supports_gc:
+    case MachOLinkingContext::objc_gc_only:
+      llvm_unreachable("GC is not supported");
+    case MachOLinkingContext::objc_retainReleaseForSimulator:
+      // The retain/release for simulator flag is already the correct
+      // encoded value for the data so just set it here.
+      Data.info.flags = (uint32_t)objCConstraint;
+      break;
+    case MachOLinkingContext::objc_retainRelease:
+      // We don't need to encode this flag, so just leave the flags as 0.
+      Data.info.flags = 0;
+      break;
+    }
+
+    Data.info.flags |= (swiftVersion << 8);
+  }
+
+  ~ObjCImageInfoAtom() override = default;
+
+  ContentType contentType() const override {
+    return DefinedAtom::typeObjCImageInfo;
+  }
+
+  Alignment alignment() const override {
+    return 4;
+  }
+
+  uint64_t size() const override {
+    return 8;
+  }
+
+  ContentPermissions permissions() const override {
+    return DefinedAtom::permR__;
+  }
+
+  ArrayRef<uint8_t> rawContent() const override {
+    return llvm::makeArrayRef(Data.bytes, size());
+  }
+
+private:
+
+  struct objc_image_info  {
+    uint32_t	version;
+    uint32_t	flags;
+  };
+
+  union {
+    objc_image_info info;
+    uint8_t bytes[8];
+  } Data;
+};
+
+class ObjCPass : public Pass {
+public:
+  ObjCPass(const MachOLinkingContext &context)
+      : _ctx(context),
+        _file(*_ctx.make_file<MachOFile>("<mach-o objc pass>")) {
+    _file.setOrdinal(_ctx.getNextOrdinalAndIncrement());
+  }
+
+  llvm::Error perform(SimpleFile &mergedFile) override {
+    // Add the image info.
+    mergedFile.addAtom(*getImageInfo());
+
+    return llvm::Error();
+  }
+
+private:
+
+  const DefinedAtom* getImageInfo() {
+    return new (_file.allocator()) ObjCImageInfoAtom(_file,
+                                                     _ctx.objcConstraint(),
+                                                     _ctx.swiftVersion());
+  }
+
+  const MachOLinkingContext   &_ctx;
+  MachOFile                   &_file;
+};
+
+
+
+void addObjCPass(PassManager &pm, const MachOLinkingContext &ctx) {
+  pm.add(llvm::make_unique<ObjCPass>(ctx));
+}
+
+} // end namespace mach_o
+} // end namespace lld