[OpenCL] Supports optional image types in C++ for OpenCL 2021

[Topotuna]

Summary

Adds support for a feature macro __opencl_c_images in C++ for
OpenCL 2021 enabling a respective optional core feature from
OpenCL 3.0.

This change aims to achieve compatibility between C++ for OpenCL
2021 and OpenCL 3.0.

[Anastasia]

clang/lib/Sema/SemaType.cpp

1739

I think we should just replace IsOpenCLC30 as it is when only used in the diagnostic that we should report the same as for OpenCL 3.0.

Also I would suggest changing name to IsOpenCLC30Compatible to make it clearer.

[Topotuna]

clang/lib/Sema/SemaType.cpp

1739

That diagnostic is responsible for __opencl_c_3d_image_writes feature while current commit addresses __opencl_c_images. I wanted to keep commits separate and was planning to finish transitioning from IsOpenCLC30 to IsOpenCLC30Compatible in a future commit.

I agree that IsOpenCLC30Compatible would be clearer. Thank you.

[Anastasia]

clang/lib/Sema/SemaType.cpp

1739

Ok, let's just only rename it for now and add a FIXME comment explaining that the variables should be unified later on.

I suspect your subsequent commits would include the unification?

[Topotuna]

Boolean variable renamed to IsOpenCLC30Compatible. FIXME comment added.

[Topotuna]

clang/lib/Sema/SemaType.cpp

1739

Yes, I will perform unification when adding support for __opencl_c_3d_image_writes optional core feature.

[Anastasia]

LGTM! Thanks

[Topotuna]

clang/lib/Sema/SemaType.cpp

1739

Change rGca3bebd8440f performs mentioned variable unification.

clang/lib/Sema/SemaType.cpp

#include "clang/Basic/OpenCLImageTypes.def"
   // FIXME: we want resulting declarations to be marked invalid, but claiming
   // the type is invalid is too strong - e.g. it causes ActOnTypeName to return
   // a null type.
   if (Result->containsErrors())
     declarator.setInvalidType();
 
   if (S.getLangOpts().OpenCL) {
     const auto &OpenCLOptions = S.getOpenCLOptions();
+    // FIXME: both variables IsOpenCLC30 and IsOpenCLC30Compatible should be
+    // unified into one when __opencl_c_3d_image_writes option is enabled in
+    // C++ for OpenCL 2021
     bool IsOpenCLC30 = (S.getLangOpts().OpenCLVersion == 300);
+    bool IsOpenCLC30Compatible =
+        S.getLangOpts().getOpenCLCompatibleVersion() == 300;
     // OpenCL C v3.0 s6.3.3 - OpenCL image types require __opencl_c_images
     // support.
     // OpenCL C v3.0 s6.2.1 - OpenCL 3d image write types requires support
     // for OpenCL C 2.0, or OpenCL C 3.0 or newer and the
     // __opencl_c_3d_image_writes feature. OpenCL C v3.0 API s4.2 - For devices
     // that support OpenCL 3.0, cl_khr_3d_image_writes must be returned when and
     // only when the optional feature is supported
     if ((Result->isImageType() || Result->isSamplerT()) &&
-        (IsOpenCLC30 &&
+        (IsOpenCLC30Compatible &&
          !OpenCLOptions.isSupported("__opencl_c_images", S.getLangOpts()))) {
       S.Diag(DS.getTypeSpecTypeLoc(), diag::err_opencl_requires_extension)
           << 0 << Result << "__opencl_c_images";
       declarator.setInvalidType();
     } else if (Result->isOCLImage3dWOType() &&
                !OpenCLOptions.isSupported("cl_khr_3d_image_writes",
                                           S.getLangOpts())) {
       S.Diag(DS.getTypeSpecTypeLoc(), diag::err_opencl_requires_extension)

clang/test/SemaOpenCL/unsupported-image.cl

 // RUN: %clang_cc1 -triple spir-unknown-unknown -verify -cl-std=CL3.0 -cl-ext=-__opencl_c_images,-__opencl_c_read_write_images,-cl_khr_3d_image_writes,-__opencl_c_3d_image_writes %s
 // RUN: %clang_cc1 -triple spir-unknown-unknown -verify -cl-std=CL3.0 -cl-ext=+__opencl_c_images,+__opencl_c_read_write_images,+cl_khr_3d_image_writes,+__opencl_c_3d_image_writes %s
 // RUN: %clang_cc1 -triple spir-unknown-unknown -verify -cl-std=CL3.0 -cl-ext=+__opencl_c_images,+__opencl_c_read_write_images,-cl_khr_3d_image_writes,-__opencl_c_3d_image_writes %s
+// RUN: %clang_cc1 -triple spir-unknown-unknown -verify -cl-std=clc++2021 -cl-ext=-__opencl_c_images,-__opencl_c_read_write_images,-cl_khr_3d_image_writes,-__opencl_c_3d_image_writes %s
+// RUN: %clang_cc1 -triple spir-unknown-unknown -verify -cl-std=clc++2021 -cl-ext=+__opencl_c_images %s
 
 #if defined(__opencl_c_images) && defined(__opencl_c_3d_image_writes)
 //expected-no-diagnostics
 #endif
 
 void test1(image1d_t i) {}
 #if !defined(__opencl_c_images)
 // expected-error@-2{{use of type '__read_only image1d_t' requires __opencl_c_images support}}