[PATCH] D108621: [HIPSPV] Add CUDA->SPIR-V address space mapping

[Henry Linjamäki via Phabricator via cfe-commits]

linjamaki created this revision.
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Add mapping for CUDA address spaces for HIP to SPIR-V
translation. This change allows HIP device code to be emitted as valid
SPIR-V by mapping unqualified pointers to generic address space and by
mapping __device__ and __shared__ AS to their equivalent AS in SPIR-V
(CrossWorkgroup and Workgroup, respectively).

Cuda's __constant__ AS is handled specially. In HIP unqualified
pointers (aka "flat" pointers) can point to __constant__ objects. Mapping
this AS to ConstantMemory would produce to illegal address space casts to
generic AS. Therefore, __constant__ AS is mapped to CrossWorkgroup.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D108621

Files:
  clang/lib/Basic/Targets/SPIR.h
  clang/test/CodeGenHIP/hipspv-addr-spaces.cpp


Index: clang/test/CodeGenHIP/hipspv-addr-spaces.cpp
===================================================================
--- /dev/null
+++ clang/test/CodeGenHIP/hipspv-addr-spaces.cpp
@@ -0,0 +1,46 @@
+// RUN: %clang_cc1 -triple spir64 -x hip -emit-llvm -fcuda-is-device \
+// RUN:   -o - %s | FileCheck %s
+
+#define __device__ __attribute__((device))
+#define __shared__ __attribute__((shared))
+#define __constant__ __attribute__((constant))
+
+// CHECK: %struct.foo_t = type { i32, i32 addrspace(4)* }
+
+// CHECK: @d ={{.*}} addrspace(1) externally_initialized global
+__device__ int d;
+
+// CHECK: @c ={{.*}} addrspace(1) externally_initialized global
+__constant__ int c;
+
+// CHECK: @s ={{.*}} addrspace(3) global
+__shared__ int s;
+
+// CHECK: @foo ={{.*}} addrspace(1) externally_initialized global %struct.foo_t
+__device__ struct foo_t {
+  int i;
+  int* pi;
+} foo;
+
+// CHECK: define {{.*}} spir_func i32 addrspace(4)* @_Z3barPi(i32 addrspace(4)*
+__device__ int* bar(int *x) {
+  return x;
+}
+
+// CHECK: define {{.*}} spir_func i32 addrspace(4)* @_Z5baz_dv()
+__device__ int* baz_d() {
+  // CHECK: ret i32 addrspace(4)* addrspacecast (i32 addrspace(1)* @d to i32 addrspace(4)*
+  return &d;
+}
+
+// CHECK: define {{.*}} spir_func i32 addrspace(4)* @_Z5baz_cv()
+__device__ int* baz_c() {
+  // CHECK: ret i32 addrspace(4)* addrspacecast (i32 addrspace(1)* @c to i32 addrspace(4)*
+  return &c;
+}
+
+// CHECK: define {{.*}} spir_func i32 addrspace(4)* @_Z5baz_sv()
+__device__ int* baz_s() {
+  // CHECK: ret i32 addrspace(4)* addrspacecast (i32 addrspace(3)* @s to i32 addrspace(4)*
+  return &s;
+}
Index: clang/lib/Basic/Targets/SPIR.h
===================================================================
--- clang/lib/Basic/Targets/SPIR.h
+++ clang/lib/Basic/Targets/SPIR.h
@@ -54,9 +54,14 @@
     0, // opencl_generic
     0, // opencl_global_device
     0, // opencl_global_host
-    0, // cuda_device
-    0, // cuda_constant
-    0, // cuda_shared
+    // cuda_* address space mapping is intended for HIPSPV (HIP to SPIR-V
+    // translation). This mapping is enabled when the language mode is HIP.
+    1, // cuda_device
+    // cuda_constant pointer can be casted to default/"flat" pointer, but in
+    // SPIR-V casts between constant and generic pointers are not allowed. For
+    // this reason cuda_constant is mapped to SPIR-V CrossWorkgroup.
+    1, // cuda_constant
+    3, // cuda_shared
     1, // sycl_global
     5, // sycl_global_device
     6, // sycl_global_host
@@ -137,6 +142,8 @@
 
   void adjust(DiagnosticsEngine &Diags, LangOptions &Opts) override {
     TargetInfo::adjust(Diags, Opts);
+    // See comment on the SPIRDefIsGenMap table.
+    bool IsHIPSPV = Opts.HIP && Opts.CUDAIsDevice;
     // FIXME: SYCL specification considers unannotated pointers and references
     // to be pointing to the generic address space. See section 5.9.3 of
     // SYCL 2020 specification.
@@ -144,7 +151,7 @@
     // language semantic along with the semantics of embedded C's default
     // address space in the same address space map. Hence the map needs to be
     // reset to allow mapping to the desired value of 'Default' entry for SYCL.
-    setAddressSpaceMap(/*DefaultIsGeneric=*/Opts.SYCLIsDevice);
+    setAddressSpaceMap(/*DefaultIsGeneric=*/Opts.SYCLIsDevice || IsHIPSPV);
   }
 
   void setSupportedOpenCLOpts() override {


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