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, 9 insertions, 8 deletions

diff --git a/intern/cycles/kernel/kernel_types.h b/intern/cycles/kernel/kernel_types.h
index 00457695e53..3a5a11d2c10 100644
--- a/intern/cycles/kernel/kernel_types.h
+++ b/intern/cycles/kernel/kernel_types.h
@@ -636,7 +636,7 @@ typedef struct AttributeDescriptor {
   float sample_weight; \
   float3 N
 
-typedef ccl_addr_space struct ccl_align(16) ShaderClosure
+typedef struct ccl_align(16) ShaderClosure
 {
   SHADER_CLOSURE_BASE;
 
@@ -747,7 +747,7 @@ enum ShaderDataObjectFlag {
                      SD_OBJECT_HAS_VOLUME_ATTRIBUTES)
 };
 
-typedef ccl_addr_space struct ccl_align(16) ShaderData
+typedef struct ccl_align(16) ShaderData
 {
   /* position */
   float3 P;
@@ -837,27 +837,28 @@ ShaderData;
 
 /* ShaderDataTinyStorage needs the same alignment as ShaderData, or else
  * the pointer cast in AS_SHADER_DATA invokes undefined behavior. */
-typedef ccl_addr_space struct ccl_align(16) ShaderDataTinyStorage
+typedef struct ccl_align(16) ShaderDataTinyStorage
 {
   char pad[sizeof(ShaderData) - sizeof(ShaderClosure) * MAX_CLOSURE];
 }
 ShaderDataTinyStorage;
-#define AS_SHADER_DATA(shader_data_tiny_storage) ((ShaderData *)shader_data_tiny_storage)
+#define AS_SHADER_DATA(shader_data_tiny_storage) \
+  ((ccl_private ShaderData *)shader_data_tiny_storage)
 
 /* Compact volume closures storage.
  *
  * Used for decoupled direct/indirect light closure storage. */
 
-ccl_addr_space struct ShaderVolumeClosure {
+typedef struct ShaderVolumeClosure {
   float3 weight;
   float sample_weight;
   float g;
-};
+} ShaderVolumeClosure;
 
-ccl_addr_space struct ShaderVolumePhases {
+typedef struct ShaderVolumePhases {
   ShaderVolumeClosure closure[MAX_VOLUME_CLOSURE];
   int num_closure;
-};
+} ShaderVolumePhases;
 
 /* Volume Stack */