Better tie together ContentType and Permissions.

Since most content types (e.g. typeCode) have a 
preferred Permission, add a function to do that mapping.
Then hook up to YAML Reader and Writer such that
the 'permissions:' key does not need to be specified unless
overriding what the content type prefers.

llvm-svn: 171929

1 files changed, 78 insertions, 0 deletions

diff --git a/lld/lib/Core/DefinedAtom.cpp b/lld/lib/Core/DefinedAtom.cpp
new file mode 100644
index 00000000000..191f12c96fd
--- /dev/null
+++ b/lld/lib/Core/DefinedAtom.cpp
@@ -0,0 +1,78 @@
+//===- DefinedAtom.cpp ------------------------------------------*- C++ -*-===//
+//
+//                             The LLVM Linker
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/ErrorHandling.h"
+
+#include "lld/Core/DefinedAtom.h"
+
+
+namespace lld {
+
+
+DefinedAtom::ContentPermissions DefinedAtom::permissions() const {
+  // By default base permissions on content type.
+  return permissions(this->contentType());
+}
+
+// Utility function for deriving permissions from content type
+DefinedAtom::ContentPermissions DefinedAtom::permissions(ContentType type) {
+  switch (type) {
+  case typeCode:
+  case typeResolver:
+  case typeBranchIsland:
+  case typeBranchShim:
+  case typeStub:
+  case typeStubHelper:
+    return permR_X;
+ 
+  case typeConstant:
+  case typeCString:
+  case typeUTF16String:
+  case typeCFI:
+  case typeLSDA:
+  case typeLiteral4:
+  case typeLiteral8:
+  case typeLiteral16:
+  case typeDTraceDOF:
+  case typeCompactUnwindInfo:
+    return permR__;
+
+  case typeData:
+  case typeZeroFill:
+  case typeObjC1Class:
+  case typeLazyPointer:
+  case typeLazyDylibPointer:
+  case typeThunkTLV:
+    return permRW_;
+
+  case typeGOT:
+  case typeConstData:
+  case typeCFString:
+  case typeInitializerPtr:
+  case typeTerminatorPtr:
+  case typeCStringPtr:
+  case typeObjCClassPtr:
+  case typeObjC2CategoryList:
+  case typeTLVInitialData:
+  case typeTLVInitialZeroFill:
+  case typeTLVInitializerPtr:
+    return permRW_L;
+  
+  case typeUnknown:
+  case typeTempLTO:
+  case typeFirstInSection:
+  case typeLastInSection:
+    return permUnknown;
+  }
+  llvm_unreachable("unknown content type");
+}
+
+
+} // namespace
+