GPU: route noexcept through GPUnoexcept() for Metal

MSL rejects the noexcept specifier outright, with a diagnostic of its own:
"'noexcept' is not supported in Metal". It applies to free functions, to
function templates and to out-of-line member definitions alike; only a noexcept
inside a class body slips through, which does not help a header that defines its
members out of line.

Author: ktf

Common/MathUtils/include/MathUtils/detail/Bracket.h

@@ -16,6 +16,8 @@
 #ifndef ALICEO2_BRACKET_H
 #define ALICEO2_BRACKET_H
 
+#include "GPUCommonDef.h"
+
 #include <GPUCommonRtypes.h>
 #ifndef GPUCA_GPUCODE_DEVICE
 #include <string>
@@ -53,9 +55,9 @@ class Bracket
   bool operator==(const Bracket<T>& other) const;
   bool operator!=(const Bracket<T>& other) const;
 
-  void setMax(T v) noexcept;
-  void setMin(T v) noexcept;
-  void set(T minv, T maxv) noexcept;
+  void setMax(T v) GPUnoexcept();
+  void setMin(T v) GPUnoexcept();
+  void set(T minv, T maxv) GPUnoexcept();
 
   T& getMax();
   T& getMin();
@@ -129,19 +131,19 @@ inline bool Bracket<T>::operator!=(const Bracket<T>& rhs) const
 }
 
 template <typename T>
-inline void Bracket<T>::setMax(T v) noexcept
+inline void Bracket<T>::setMax(T v) GPUnoexcept()
 {
   mMax = v;
 }
 
 template <typename T>
-inline void Bracket<T>::setMin(T v) noexcept
+inline void Bracket<T>::setMin(T v) GPUnoexcept()
 {
   mMin = v;
 }
 
 template <typename T>
-inline void Bracket<T>::set(T minv, T maxv) noexcept
+inline void Bracket<T>::set(T minv, T maxv) GPUnoexcept()
 {
   this->setMin(minv);
   this->setMax(maxv);

GPU/Common/GPUCommonAlgorithm.h

@@ -51,40 +51,40 @@ class GPUCommonAlgorithm
  private:
   // Quicksort implementation
   template <typename I>
-  GPUd() static void QuickSort(I f, I l) noexcept;
+  GPUd() static void QuickSort(I f, I l) GPUnoexcept();
 
   // Quicksort implementation
   template <typename I, typename Cmp>
-  GPUd() static void QuickSort(I f, I l, Cmp cmp) noexcept;
+  GPUd() static void QuickSort(I f, I l, Cmp cmp) GPUnoexcept();
 
   // Insertionsort implementation
   template <typename I, typename Cmp>
-  GPUd() static void InsertionSort(I f, I l, Cmp cmp) noexcept;
+  GPUd() static void InsertionSort(I f, I l, Cmp cmp) GPUnoexcept();
 
   // Helper for Quicksort implementation
   template <typename I, typename Cmp>
-  GPUd() static I MedianOf3Select(I f, I l, Cmp cmp) noexcept;
+  GPUd() static I MedianOf3Select(I f, I l, Cmp cmp) GPUnoexcept();
 
   // Helper for Quicksort implementation
   template <typename I, typename T, typename Cmp>
-  GPUd() static I UnguardedPartition(I f, I l, T piv, Cmp cmp) noexcept;
+  GPUd() static I UnguardedPartition(I f, I l, T piv, Cmp cmp) GPUnoexcept();
 
   // Helper
   template <typename I>
-  GPUd() static void IterSwap(I a, I b) noexcept;
+  GPUd() static void IterSwap(I a, I b) GPUnoexcept();
 };
 
 #ifndef GPUCA_ALGORITHM_STD
 template <typename I>
-GPUdi() void GPUCommonAlgorithm::IterSwap(I a, I b) noexcept
+GPUdi() void GPUCommonAlgorithm::IterSwap(I a, I b) GPUnoexcept()
 {
   auto tmp = *a;
   *a = *b;
   *b = tmp;
 }
 
 template <typename I, typename Cmp>
-GPUdi() void GPUCommonAlgorithm::InsertionSort(I f, I l, Cmp cmp) noexcept
+GPUdi() void GPUCommonAlgorithm::InsertionSort(I f, I l, Cmp cmp) GPUnoexcept()
 {
   auto it0{f};
   while (it0 != l) {
@@ -102,7 +102,7 @@ GPUdi() void GPUCommonAlgorithm::InsertionSort(I f, I l, Cmp cmp) noexcept
 }
 
 template <typename I, typename Cmp>
-GPUdi() I GPUCommonAlgorithm::MedianOf3Select(I f, I l, Cmp cmp) noexcept
+GPUdi() I GPUCommonAlgorithm::MedianOf3Select(I f, I l, Cmp cmp) GPUnoexcept()
 {
   auto m = f + (l - f) / 2;
 
@@ -126,7 +126,7 @@ GPUdi() I GPUCommonAlgorithm::MedianOf3Select(I f, I l, Cmp cmp) noexcept
 }
 
 template <typename I, typename T, typename Cmp>
-GPUdi() I GPUCommonAlgorithm::UnguardedPartition(I f, I l, T piv, Cmp cmp) noexcept
+GPUdi() I GPUCommonAlgorithm::UnguardedPartition(I f, I l, T piv, Cmp cmp) GPUnoexcept()
 {
   do {
     while (cmp(*f, piv)) {
@@ -146,7 +146,7 @@ GPUdi() I GPUCommonAlgorithm::UnguardedPartition(I f, I l, T piv, Cmp cmp) noexc
 }
 
 template <typename I, typename Cmp>
-GPUdi() void GPUCommonAlgorithm::QuickSort(I f, I l, Cmp cmp) noexcept
+GPUdi() void GPUCommonAlgorithm::QuickSort(I f, I l, Cmp cmp) GPUnoexcept()
 {
   if (f == l) {
     return;
@@ -204,7 +204,7 @@ GPUdi() void GPUCommonAlgorithm::QuickSort(I f, I l, Cmp cmp) noexcept
 }
 
 template <typename I>
-GPUdi() void GPUCommonAlgorithm::QuickSort(I f, I l) noexcept
+GPUdi() void GPUCommonAlgorithm::QuickSort(I f, I l) GPUnoexcept()
 {
   QuickSort(f, l, [](auto&& x, auto&& y) { return x < y; });
 }

GPU/Common/GPUCommonDefAPI.h

@@ -49,6 +49,7 @@
   #define GPUconstant()                             // constant memory variable declaraion
   #define GPUconstexpr() static constexpr           // constexpr on GPU that needs to be instantiated for dynamic access (e.g. arrays), becomes __constant on GPU
   #define GPUglobalconstexpr() constexpr            // constexpr variable at program scope, needs the constant address space in MSL
+  #define GPUnoexcept() noexcept                    // noexcept where the backend supports it
   #define GPUprivate()                              // private memory variable declaration
   #define GPUgeneric()                              // reference / ptr to generic address space
   #define GPUbarrier()                              // synchronize all GPU threads in block
@@ -162,6 +163,7 @@
   #define GPUconstant() constant // TODO: possibly add const __restrict where possible later!
   #define GPUconstexpr() constant
   #define GPUglobalconstexpr() constant constexpr
+  #define GPUnoexcept()
   #define GPUprivate() thread
   #define GPUgeneric()
   #define GPUglobalref() device
@@ -259,6 +261,9 @@
 #ifndef GPUglobalconstexpr
 #define GPUglobalconstexpr() constexpr
 #endif
+#ifndef GPUnoexcept
+#define GPUnoexcept() noexcept
+#endif
 
 #define GPUrestrict() __restrict__
 
@@ -281,5 +286,5 @@
   #define get_group_id(dim) iBlock
 #endif
 
-    // clang-format on
+// clang-format on
 #endif