Triple: Add opencl environment type

[• tstellarAMD]

Summary

For AMDGPU, we have been using the operating system component of the triple
for specifying the low-level runtime that is being used. The rationale for
this is that the host operating system (e.g. Linux) is irrelevant for GPU code,
since its execution enviroment will be mostly controled by the low-level runtime
being used to execute the code.

In most cases, higher level languages have their own runtime which is
implemented on top of the low-level runtime. The kernel ABIs of each
language mostly depend on the low-level runtime, but there may be some
slight differences between languages. OpenCL for example, may append
additional arguments to the kernel in order to pass values like global
offsets or buffers for printf. OpenMP, HCC, or other languages may want
to add their own values which differ from OpenCL.

The reason for adding a new opencl environment type is to make it possible for the backend
to distinguish between the ABIs of the higher-level languages and handle them correctly.
It seems cleaner to use the enviroment component for this rather than creating a new
OS type for every combination of low-level runtime / high-level language.

[pekka.jaaskelainen]

Makes sense to me. How to differentiate between OpenCL implementations? With the OS setting?

[• tstellarAMD]

In D24735#547257, @pekka.jaaskelainen wrote:

Makes sense to me. How to differentiate between OpenCL implementations? With the OS setting?

I was thinking the vendor field could be used for this. So, for example, if pocl used the hsa runtime, the triple would be: amdgcn-pocl-amdhsa-opencl.

[pekka.jaaskelainen]

Alright. LGTM!

[Anastasia]

Could we add a clang driver test too checking new triple?

include/llvm/ADT/Triple.h

194 ↗

(On Diff #71846)

What would be the difference to AMDOpenCL item above?

[• tstellarAMD]

include/llvm/ADT/Triple.h

194 ↗

(On Diff #71846)

AMDOpenCL was used with the X86 arch only. I wanted to add something that would be more extensible and would make sense for other vendors.

[• tstellarAMD]

In D24735#549076, @Anastasia wrote:

Could we add a clang driver test too checking new triple?

https://reviews.llvm.org/D24813

[chandlerc]

In D24735#547361, @tstellarAMD wrote:

In D24735#547257, @pekka.jaaskelainen wrote:

Makes sense to me. How to differentiate between OpenCL implementations? With the OS setting?

I was thinking the vendor field could be used for this. So, for example, if pocl used the hsa runtime, the triple would be: amdgcn-pocl-amdhsa-opencl.

Just as an FYI:

Generally the vendor shouldn't be used to control *semantics* anywhere. It should just be used to find tools or label things.

If you have a different ABI, you want a different environment entry typically.

In that sense this seems like a nice improvement.

[Anastasia]

include/llvm/ADT/Triple.h

194 ↗

(On Diff #71846)

I see. Could AMDOpenCL be replaced by OpenCL as more generic item then?

llvm/trunk/include/llvm/ADT/Triple.h

enum EnvironmentType {
     MuslEABI,
     MuslEABIHF,
 
     MSVC,
     Itanium,
     Cygnus,
     AMDOpenCL,
     CoreCLR,
-    LastEnvironmentType = CoreCLR
+    OpenCL,
+    LastEnvironmentType = OpenCL
   };
   enum ObjectFormatType {
     UnknownObjectFormat,
 
     COFF,
     ELF,
     MachO,
   };

llvm/trunk/lib/Support/Triple.cpp

const char *Triple::getEnvironmentTypeName(EnvironmentType Kind) {
   case Musl: return "musl";
   case MuslEABI: return "musleabi";
   case MuslEABIHF: return "musleabihf";
   case MSVC: return "msvc";
   case Itanium: return "itanium";
   case Cygnus: return "cygnus";
   case AMDOpenCL: return "amdopencl";
   case CoreCLR: return "coreclr";
+  case OpenCL: return "opencl";
   }
 
   llvm_unreachable("Invalid EnvironmentType!");
 }
 
 static Triple::ArchType parseBPFArch(StringRef ArchName) {
   if (ArchName.equals("bpf")) {
     if (sys::IsLittleEndianHost)
return StringSwitch<Triple::EnvironmentType>(EnvironmentName)
     .StartsWith("musleabihf", Triple::MuslEABIHF)
     .StartsWith("musleabi", Triple::MuslEABI)
     .StartsWith("musl", Triple::Musl)
     .StartsWith("msvc", Triple::MSVC)
     .StartsWith("itanium", Triple::Itanium)
     .StartsWith("cygnus", Triple::Cygnus)
     .StartsWith("amdopencl", Triple::AMDOpenCL)
     .StartsWith("coreclr", Triple::CoreCLR)
+    .StartsWith("opencl", Triple::OpenCL)
     .Default(Triple::UnknownEnvironment);
 }
 
 static Triple::ObjectFormatType parseFormat(StringRef EnvironmentName) {
   return StringSwitch<Triple::ObjectFormatType>(EnvironmentName)
     .EndsWith("coff", Triple::COFF)
     .EndsWith("elf", Triple::ELF)
     .EndsWith("macho", Triple::MachO)

llvm/trunk/unittests/ADT/TripleTest.cpp

TEST(TripleTest, ParsedIDs) {
   EXPECT_EQ(Triple::UnknownEnvironment, T.getEnvironment());
 
   T = Triple("amdgcn-amd-amdhsa");
   EXPECT_EQ(Triple::amdgcn, T.getArch());
   EXPECT_EQ(Triple::AMD, T.getVendor());
   EXPECT_EQ(Triple::AMDHSA, T.getOS());
   EXPECT_EQ(Triple::UnknownEnvironment, T.getEnvironment());
 
+  T = Triple("amdgcn-amd-amdhsa-opencl");
+  EXPECT_EQ(Triple::amdgcn, T.getArch());
+  EXPECT_EQ(Triple::AMD, T.getVendor());
+  EXPECT_EQ(Triple::AMDHSA, T.getOS());
+  EXPECT_EQ(Triple::OpenCL, T.getEnvironment());
+
   T = Triple("huh");
   EXPECT_EQ(Triple::UnknownArch, T.getArch());
 }
 
 static std::string Join(StringRef A, StringRef B, StringRef C) {
   std::string Str = A; Str += '-'; Str += B; Str += '-'; Str += C;
   return Str;
 }