[PATCH] D123298: [NFC] [AST] Reduce the size of TemplateParmPosition

[Aaron Ballman via Phabricator via cfe-commits]

aaron.ballman added inline comments.


================
Comment at: clang/include/clang/AST/DeclTemplate.h:1151-1152
 protected:
-  // FIXME: These probably don't need to be ints. int:5 for depth, int:8 for
-  // position? Maybe?
-  unsigned Depth;
-  unsigned Position;
+#define DEPTH_BITWIDTH 20
+#define POSITION_BITWIDTH 12
+  unsigned Depth : DEPTH_BITWIDTH;
----------------
Just as constant as a macro, but without all the macro issues.


================
Comment at: clang/include/clang/AST/DeclTemplate.h:1156-1157
 
-  TemplateParmPosition(unsigned D, unsigned P) : Depth(D), Position(P) {}
+  static constexpr unsigned MaxDepth = (1l << DEPTH_BITWIDTH) - 1;
+  static constexpr unsigned MaxPosition = (1l << POSITION_BITWIDTH) - 1;
+
----------------
ChuanqiXu wrote:
> I don't find standard way to generate the maximum value for bit fields.. So I choose to calculate it by hand. 
Since we're adding 1 everywhere we look at these values, would it make more sense to drop the -1 here and the +1 elsewhere?


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D123298/new/

https://reviews.llvm.org/D123298