Make .bc en/decoding of AttrKind stable

The bitcode representation attribute kinds are encoded into / decoded from
should be independent of the current set of LLVM attributes and their position
in the AttrKind enum. This patch explicitly encodes attributes to fixed bitcode
values.

With this patch applied, LLVM does not silently misread attributes written by
LLVM 3.3. We also enhance the decoding slightly such that an error message is
printed if an unknown AttrKind encoding was dected.

Bonus: Dropping bitcode attributes from AttrKind is now easy, as old AttrKinds
       do not need to be kept to support the Bitcode reader.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187186 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 41 insertions, 0 deletions

diff --git a/include/llvm/Bitcode/LLVMBitCodes.h b/include/llvm/Bitcode/LLVMBitCodes.h
index f9690d5..463e3b9 100644
--- a/include/llvm/Bitcode/LLVMBitCodes.h
+++ b/include/llvm/Bitcode/LLVMBitCodes.h
@@ -330,6 +330,47 @@ namespace bitc {
   enum UseListCodes {
     USELIST_CODE_ENTRY = 1   // USELIST_CODE_ENTRY: TBD.
   };
+
+  enum AttributeKindCodes {
+    // = 0 is unused
+    ATTR_KIND_ALIGNMENT = 1,
+    ATTR_KIND_ALWAYS_INLINE = 2,
+    ATTR_KIND_BY_VAL = 3,
+    ATTR_KIND_INLINE_HINT = 4,
+    ATTR_KIND_IN_REG = 5,
+    ATTR_KIND_MIN_SIZE = 6,
+    ATTR_KIND_NAKED = 7,
+    ATTR_KIND_NEST = 8,
+    ATTR_KIND_NO_ALIAS = 9,
+    ATTR_KIND_NO_BUILTIN = 10,
+    ATTR_KIND_NO_CAPTURE = 11,
+    ATTR_KIND_NO_DUPLICATE = 12,
+    ATTR_KIND_NO_IMPLICIT_FLOAT = 13,
+    ATTR_KIND_NO_INLINE = 14,
+    ATTR_KIND_NON_LAZY_BIND = 15,
+    ATTR_KIND_NO_RED_ZONE = 16,
+    ATTR_KIND_NO_RETURN = 17,
+    ATTR_KIND_NO_UNWIND = 18,
+    ATTR_KIND_OPTIMIZE_FOR_SIZE = 19,
+    ATTR_KIND_READ_NONE = 20,
+    ATTR_KIND_READ_ONLY = 21,
+    ATTR_KIND_RETURNED = 22,
+    ATTR_KIND_RETURNS_TWICE = 23,
+    ATTR_KIND_S_EXT = 24,
+    ATTR_KIND_STACK_ALIGNMENT = 25,
+    ATTR_KIND_STACK_PROTECT = 26,
+    ATTR_KIND_STACK_PROTECT_REQ = 27,
+    ATTR_KIND_STACK_PROTECT_STRONG = 28,
+    ATTR_KIND_STRUCT_RET = 29,
+    ATTR_KIND_SANITIZE_ADDRESS = 30,
+    ATTR_KIND_SANITIZE_THREAD = 31,
+    ATTR_KIND_SANITIZE_MEMORY = 32,
+    ATTR_KIND_UW_TABLE = 33,
+    ATTR_KIND_Z_EXT = 34,
+    ATTR_KIND_BUILTIN = 35,
+    ATTR_KIND_COLD = 36
+  };
+
 } // End bitc namespace
 } // End llvm namespace