[PATCH] D28318: [TableGen] Only normalize the spelling of GNU-style attributes.

[Justin Lebar via Phabricator via cfe-commits]

jlebar created this revision.
jlebar added a reviewer: rnk.
jlebar added subscribers: tra, cfe-commits.

When Sema looks up an attribute name, it strips off leading and trailing
"__" if the attribute is GNU-style.  That is, __attribute__((foo)) and
__attribute__((__foo__)) are equivalent.

This is only true for GNU-style attributes.  In particular,
__declspec(__foo__) is not equivalent to __declspec(foo), and Sema
respects this difference.

This patch fixes TableGen to match Sema's behavior.  The spelling
'GNU<"__foo__">' should be normalized to 'GNU<"foo">', but
'Declspec<"__foo__">' should not be changed.

This is necessary to make CUDA compilation work on Windows, because e.g.
the __device__ attribute is spelled __declspec(__device__).

Attr.td does not contain any Declspec spellings that start or end with
"__", so this change should not affect any other attributes.


https://reviews.llvm.org/D28318

Files:
  clang/utils/TableGen/ClangAttrEmitter.cpp


Index: clang/utils/TableGen/ClangAttrEmitter.cpp
===================================================================
--- clang/utils/TableGen/ClangAttrEmitter.cpp
+++ clang/utils/TableGen/ClangAttrEmitter.cpp
@@ -133,10 +133,9 @@
   return Name.trim("_");
 }
 
-// Normalize attribute spelling only if the spelling has both leading
-// and trailing underscores. For example, __ms_struct__ will be 
-// normalized to "ms_struct"; __cdecl will remain intact.
-static StringRef NormalizeAttrSpelling(StringRef AttrSpelling) {
+// Normalize the spelling of a GNU attribute (i.e. "x" in "__attribute__((x))"),
+// removing "__" if it appears at the beginning and end of the attribute's name.
+static StringRef NormalizeGNUAttrSpelling(StringRef AttrSpelling) {
   if (AttrSpelling.startswith("__") && AttrSpelling.endswith("__")) {
     AttrSpelling = AttrSpelling.substr(2, AttrSpelling.size() - 4);
   }
@@ -3045,7 +3044,11 @@
 
         assert(Matches && "Unsupported spelling variety found");
 
-        Spelling += NormalizeAttrSpelling(RawSpelling);
+        if (Variety == "GNU")
+          Spelling += NormalizeGNUAttrSpelling(RawSpelling);
+        else
+          Spelling += RawSpelling;
+
         if (SemaHandler)
           Matches->push_back(StringMatcher::StringPair(Spelling,
                               "return AttributeList::AT_" + AttrName + ";"));


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