Cycles: Kernel address space changes for MSL

This is the first of a sequence of changes to support compiling Cycles kernels as MSL (Metal Shading Language) in preparation for a Metal GPU device implementation.

MSL requires that all pointer types be declared with explicit address space attributes (device, thread, etc...). There is already precedent for this with Cycles' address space macros (ccl_global, ccl_private, etc...), therefore the first step of MSL-enablement is to apply these consistently. Line-for-line this represents the largest change required to enable MSL. Applying this change first will simplify future patches as well as offering the emergent benefit of enhanced descriptiveness.

The vast majority of deltas in this patch fall into one of two cases:

- Ensuring ccl_private is specified for thread-local pointer types
- Ensuring ccl_global is specified for device-wide pointer types

Additionally, the ccl_addr_space qualifier can be removed. Prior to Cycles X, ccl_addr_space was used as a context-dependent address space qualifier, but now it is either redundant (e.g. in struct typedefs), or can be replaced by ccl_global in the case of pointer types. Associated function variants (e.g. lcg_step_float_addrspace) are also redundant.

In cases where address space qualifiers are chained with "const", this patch places the address space qualifier first. The rationale for this is that the choice of address space is likely to have the greater impact on runtime performance and overall architecture.

The final part of this patch is the addition of a metal/compat.h header. This is partially complete and will be extended in future patches, paving the way for the full Metal implementation.

Ref T92212

Reviewed By: brecht

Maniphest Tasks: T92212

Differential Revision: https://developer.blender.org/D12864

1 files changed, 10 insertions, 3 deletions

diff --git a/intern/cycles/kernel/kernel_jitter.h b/intern/cycles/kernel/kernel_jitter.h
index 1beaf3cc2b2..1f745ab1da9 100644
--- a/intern/cycles/kernel/kernel_jitter.h
+++ b/intern/cycles/kernel/kernel_jitter.h
@@ -72,7 +72,10 @@ ccl_device_inline float cmj_randfloat_simple(uint i, uint p)
   return cmj_hash_simple(i, p) * (1.0f / (float)0xFFFFFFFF);
 }
 
-ccl_device float pmj_sample_1D(const KernelGlobals *kg, uint sample, uint rng_hash, uint dimension)
+ccl_device float pmj_sample_1D(ccl_global const KernelGlobals *kg,
+                               uint sample,
+                               uint rng_hash,
+                               uint dimension)
 {
   /* Perform Owen shuffle of the sample number to reorder the samples. */
 #ifdef _SIMPLE_HASH_
@@ -115,8 +118,12 @@ ccl_device float pmj_sample_1D(const KernelGlobals *kg, uint sample, uint rng_ha
   return fx;
 }
 
-ccl_device void pmj_sample_2D(
-    const KernelGlobals *kg, uint sample, uint rng_hash, uint dimension, float *x, float *y)
+ccl_device void pmj_sample_2D(ccl_global const KernelGlobals *kg,
+                              uint sample,
+                              uint rng_hash,
+                              uint dimension,
+                              ccl_private float *x,
+                              ccl_private float *y)
 {
   /* Perform a shuffle on the sample number to reorder the samples. */
 #ifdef _SIMPLE_HASH_