TableGen: Use 'enum : uint64_t' for feature flags to fix -Wmicrosoft

clang-cl would warn that this value is not representable in 'int':
  enum { FeatureX = 1ULL << 31 };
All MS enums are 'ints' unless otherwise specified, so we have to use an
explicit type.  The AMDGPU target just hit 32 features, triggering this
warning.

Now that we have C++11 strong enum types, we can also eliminate the
'const uint64_t' codepath from tablegen and just use 'enum : uint64_t'.

llvm-svn: 231697

1 files changed, 16 insertions, 29 deletions

diff --git a/llvm/utils/TableGen/SubtargetEmitter.cpp b/llvm/utils/TableGen/SubtargetEmitter.cpp
index d8cf0d1..3403afb 100644
--- a/llvm/utils/TableGen/SubtargetEmitter.cpp
+++ b/llvm/utils/TableGen/SubtargetEmitter.cpp
@@ -128,42 +128,29 @@ void SubtargetEmitter::Enumeration(raw_ostream &OS,
 
   OS << "namespace " << Target << " {\n";
 
-  // For bit flag enumerations with more than 32 items, emit constants.
-  // Emit an enum for everything else.
-  if (isBits && N > 32) {
-    // For each record
-    for (unsigned i = 0; i < N; i++) {
-      // Next record
-      Record *Def = DefList[i];
-
-      // Get and emit name and expression (1 << i)
-      OS << "  const uint64_t " << Def->getName() << " = 1ULL << " << i << ";\n";
-    }
-  } else {
-    // Open enumeration
-    OS << "enum {\n";
-
-    // For each record
-    for (unsigned i = 0; i < N;) {
-      // Next record
-      Record *Def = DefList[i];
+  // Open enumeration. Use a 64-bit underlying type.
+  OS << "enum : uint64_t {\n";
 
-      // Get and emit name
-      OS << "  " << Def->getName();
+  // For each record
+  for (unsigned i = 0; i < N;) {
+    // Next record
+    Record *Def = DefList[i];
 
-      // If bit flags then emit expression (1 << i)
-      if (isBits)  OS << " = " << " 1ULL << " << i;
+    // Get and emit name
+    OS << "  " << Def->getName();
 
-      // Depending on 'if more in the list' emit comma
-      if (++i < N) OS << ",";
+    // If bit flags then emit expression (1 << i)
+    if (isBits)  OS << " = " << " 1ULL << " << i;
 
-      OS << "\n";
-    }
+    // Depending on 'if more in the list' emit comma
+    if (++i < N) OS << ",";
 
-    // Close enumeration
-    OS << "};\n";
+    OS << "\n";
   }
 
+  // Close enumeration
+  OS << "};\n";
+
   OS << "}\n";
 }