TPCFastTransformation: place shared constants in the constant address space

MSL requires every variable at program scope, class-scope statics included, to
name an address space. GPUglobalconstexpr() expands to constexpr everywhere
except Metal, so this is a no-op for host, CUDA, HIP, OpenCL and cling.

Author: ktf

GPU/TPCFastTransformation/TPCFastSpaceChargeCorrection.h

@@ -285,7 +285,7 @@ class TPCFastSpaceChargeCorrection : public FlatObject
   /// release temporary memory used during construction
   void releaseConstructionMemory();
 
-  static constexpr float kMaxCorrection = 100.f; ///< maximum correction value, used to protect from FPEs
+  static GPUglobalconstexpr() float kMaxCorrection = 100.f; ///< maximum correction value, used to protect from FPEs
 
   /// _______________  Data members  _______________________________________________
 

GPU/TPCFastTransformation/TPCFastTransform.h

@@ -17,6 +17,8 @@
 #ifndef ALICEO2_GPUCOMMON_TPCFASTTRANSFORMATION_TPCFASTTRANSFORM_H
 #define ALICEO2_GPUCOMMON_TPCFASTTRANSFORMATION_TPCFASTTRANSFORM_H
 
+#include "GPUCommonDef.h"
+
 #include "FlatObject.h"
 #include "TPCFastTransformGeo.h"
 #include "TPCFastSpaceChargeCorrection.h"
@@ -94,8 +96,8 @@ struct TPCSlowSpaceChargeCorrection {
 class TPCFastTransform : public FlatObject
 {
  public:
-  static constexpr float DEFLUMI = -1e6f; // default value to check if member was set
-  static constexpr float DEFIDC = -1e6f;  // default value to check if member was set
+  static GPUglobalconstexpr() float DEFLUMI = -1e6f; // default value to check if member was set
+  static GPUglobalconstexpr() float DEFIDC = -1e6f;  // default value to check if member was set
 
   /// _____________  Constructors / destructors __________________________
 

GPU/TPCFastTransformation/TPCFastTransformGeo.h

@@ -175,9 +175,9 @@ class TPCFastTransformGeo
  private:
   /// _______________  Data members  _______________________________________________
 
-  static constexpr int32_t NumberOfSectors = o2::tpc::constants::MAXSECTOR; ///< Number of TPC sectors ( sector = inner + outer sector )
-  static constexpr int32_t NumberOfSectorsA = NumberOfSectors / 2;          ///< Number of TPC sectors side A
-  static constexpr int32_t MaxNumberOfRows = 160;                           ///< Max Number of TPC rows in a sector - MUST NOT CHANGE THIS due to on-disk format of stored maps
+  static GPUglobalconstexpr() int32_t NumberOfSectors = o2::tpc::constants::MAXSECTOR; ///< Number of TPC sectors ( sector = inner + outer sector )
+  static GPUglobalconstexpr() int32_t NumberOfSectorsA = NumberOfSectors / 2;          ///< Number of TPC sectors side A
+  static GPUglobalconstexpr() int32_t MaxNumberOfRows = 160;                           ///< Max Number of TPC rows in a sector - MUST NOT CHANGE THIS due to on-disk format of stored maps
 
   /// _______________  Construction control  _______________________________________________
 

GPU/TPCFastTransformation/TPCFastTransformPOD.h

@@ -17,6 +17,8 @@
 #ifndef ALICEO2_GPU_TPCFastTransformPOD_H
 #define ALICEO2_GPU_TPCFastTransformPOD_H
 
+#include "GPUCommonDef.h"
+
 #include "GPUCommonRtypes.h"
 #include "TPCFastTransform.h"
 #include "TPCFastTransformGeoPOD.h"
@@ -240,10 +242,10 @@ class TPCFastTransformPOD
 
   GPUd() float convDriftLengthToTime(float driftLength, float vertexTime) const;
 
-  static constexpr int NROWS = o2::tpc::constants::MAXGLOBALPADROW;
-  static constexpr int NSECTORS = o2::tpc::constants::MAXSECTOR;
-  static constexpr int NSECTORSA = o2::tpc::constants::MAXSECTOR / 2;
-  static constexpr int NSplineIDs = 3; ///< number of spline data sets for each sector/row
+  static GPUglobalconstexpr() int NROWS = o2::tpc::constants::MAXGLOBALPADROW;
+  static GPUglobalconstexpr() int NSECTORS = o2::tpc::constants::MAXSECTOR;
+  static GPUglobalconstexpr() int NSECTORSA = o2::tpc::constants::MAXSECTOR / 2;
+  static GPUglobalconstexpr() int NSplineIDs = 3; ///< number of spline data sets for each sector/row
 
  private:
 #if !defined(GPUCA_GPUCODE)