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

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.

Patch by linjamaki (Henry Linjamäki)!

Differential Revision: https://reviews.llvm.org/D108621

clang/lib/Basic/Targets/SPIR.h

@@ -56,9 +56,14 @@ static const unsigned SPIRDefIsGenMap[] = {
     0, // opencl_generic
     0, // opencl_global_device
     0, // opencl_global_host
-    0, // cuda_device
+    // cuda_* address space mapping is intended for HIPSPV (HIP to SPIR-V
-    0, // cuda_constant
+    // translation). This mapping is enabled when the language mode is HIP.
-    0, // cuda_shared
+    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
@@ -74,6 +79,8 @@ class LLVM_LIBRARY_VISIBILITY BaseSPIRTargetInfo : public TargetInfo {
 protected:
   BaseSPIRTargetInfo(const llvm::Triple &Triple, const TargetOptions &)
       : TargetInfo(Triple) {
+    assert((Triple.isSPIR() || Triple.isSPIRV()) &&
+           "Invalid architecture for SPIR or SPIR-V.");
     assert(getTriple().getOS() == llvm::Triple::UnknownOS &&
            "SPIR(-V) target must use unknown OS");
     assert(getTriple().getEnvironment() == llvm::Triple::UnknownEnvironment &&
@@ -137,11 +144,16 @@ public:
     // 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.
-    // Currently, there is no way of representing SYCL's default address space
+    // Currently, there is no way of representing SYCL's and HIP's default
-    // language semantic along with the semantics of embedded C's default
+    // address space language semantic along with the semantics of embedded C's
-    // address space in the same address space map. Hence the map needs to be
+    // default address space in the same address space map. Hence the map needs
-    // reset to allow mapping to the desired value of 'Default' entry for SYCL.
+    // to be reset to allow mapping to the desired value of 'Default' entry for
-    setAddressSpaceMap(/*DefaultIsGeneric=*/Opts.SYCLIsDevice);
+    // SYCL and HIP.
+    setAddressSpaceMap(
+        /*DefaultIsGeneric=*/Opts.SYCLIsDevice ||
+        // The address mapping from HIP language for device code is only defined
+        // for SPIR-V.
+        (getTriple().isSPIRV() && Opts.HIP && Opts.CUDAIsDevice));
   }
 
   void setSupportedOpenCLOpts() override {
@@ -159,6 +171,7 @@ class LLVM_LIBRARY_VISIBILITY SPIRTargetInfo : public BaseSPIRTargetInfo {
 public:
   SPIRTargetInfo(const llvm::Triple &Triple, const TargetOptions &Opts)
       : BaseSPIRTargetInfo(Triple, Opts) {
+    assert(Triple.isSPIR() && "Invalid architecture for SPIR.");
     assert(getTriple().getOS() == llvm::Triple::UnknownOS &&
            "SPIR target must use unknown OS");
     assert(getTriple().getEnvironment() == llvm::Triple::UnknownEnvironment &&
@@ -177,6 +190,8 @@ class LLVM_LIBRARY_VISIBILITY SPIR32TargetInfo : public SPIRTargetInfo {
 public:
   SPIR32TargetInfo(const llvm::Triple &Triple, const TargetOptions &Opts)
       : SPIRTargetInfo(Triple, Opts) {
+    assert(Triple.getArch() == llvm::Triple::spir &&
+           "Invalid architecture for 32-bit SPIR.");
     PointerWidth = PointerAlign = 32;
     SizeType = TargetInfo::UnsignedInt;
     PtrDiffType = IntPtrType = TargetInfo::SignedInt;
@@ -192,6 +207,8 @@ class LLVM_LIBRARY_VISIBILITY SPIR64TargetInfo : public SPIRTargetInfo {
 public:
   SPIR64TargetInfo(const llvm::Triple &Triple, const TargetOptions &Opts)
       : SPIRTargetInfo(Triple, Opts) {
+    assert(Triple.getArch() == llvm::Triple::spir64 &&
+           "Invalid architecture for 64-bit SPIR.");
     PointerWidth = PointerAlign = 64;
     SizeType = TargetInfo::UnsignedLong;
     PtrDiffType = IntPtrType = TargetInfo::SignedLong;
@@ -207,6 +224,7 @@ class LLVM_LIBRARY_VISIBILITY SPIRVTargetInfo : public BaseSPIRTargetInfo {
 public:
   SPIRVTargetInfo(const llvm::Triple &Triple, const TargetOptions &Opts)
       : BaseSPIRTargetInfo(Triple, Opts) {
+    assert(Triple.isSPIRV() && "Invalid architecture for SPIR-V.");
     assert(getTriple().getOS() == llvm::Triple::UnknownOS &&
            "SPIR-V target must use unknown OS");
     assert(getTriple().getEnvironment() == llvm::Triple::UnknownEnvironment &&
@@ -225,6 +243,8 @@ class LLVM_LIBRARY_VISIBILITY SPIRV32TargetInfo : public SPIRVTargetInfo {
 public:
   SPIRV32TargetInfo(const llvm::Triple &Triple, const TargetOptions &Opts)
       : SPIRVTargetInfo(Triple, Opts) {
+    assert(Triple.getArch() == llvm::Triple::spirv32 &&
+           "Invalid architecture for 32-bit SPIR-V.");
     PointerWidth = PointerAlign = 32;
     SizeType = TargetInfo::UnsignedInt;
     PtrDiffType = IntPtrType = TargetInfo::SignedInt;
@@ -240,6 +260,8 @@ class LLVM_LIBRARY_VISIBILITY SPIRV64TargetInfo : public SPIRVTargetInfo {
 public:
   SPIRV64TargetInfo(const llvm::Triple &Triple, const TargetOptions &Opts)
       : SPIRVTargetInfo(Triple, Opts) {
+    assert(Triple.getArch() == llvm::Triple::spirv64 &&
+           "Invalid architecture for 64-bit SPIR-V.");
     PointerWidth = PointerAlign = 64;
     SizeType = TargetInfo::UnsignedLong;
     PtrDiffType = IntPtrType = TargetInfo::SignedLong;

clang/test/CodeGenHIP/hipspv-addr-spaces.cpp

@@ -0,0 +1,46 @@
+// RUN: %clang_cc1 -triple spirv64 -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;
+}