[OpenCL] Prevent adding extension pragma by default

[Anastasia]

Summary

Currently, extension pragma is always added when new OpenCL option (extension or feature) is added to the frontend. This change adds a new field for the options that allows specifying the need for the pragmas.

For backward compatibility, the pragmas are added for all extensions prior to OpenCL 3.0.

For OpenCL 3.0 features and future extensions (those that are documented in the unified spec only), the pragmas is not to be added unless they are explicitly requested and their behavior is sufficiently well explained.

[azabaznov]

Thanks! I review is shortly. As for now, I also was doing some refactoring: https://reviews.llvm.org/D97058. Check-clang passes, as I see there are no conflicts for now.

[svenvh]

clang/include/clang/Basic/OpenCLExtensions.def

24

typo

65

You're introducing a double space.

clang/lib/Parse/ParsePragma.cpp

785

I fail to understand why this is needed, so perhaps this needs a bit more explanation. Extensions that should continue to support pragmas already have their WithPragma field set to true via OpenCLExtensions.def. Why do we need to dynamically modify the field?

[azabaznov]

clang/include/clang/Basic/OpenCLExtensions.def

71

I think core and optional core features do not require pragma too. So for example 3d image writes or fp64 do not require pragma in OpenCL C 2.0. Isn't that so?

clang/test/SemaOpenCL/extension-version.cl

217

Again about core or optional core: don't you feel that current diagnostic is good already (https://godbolt.org/z/Kcjdvr)?

[Anastasia]

clang/include/clang/Basic/OpenCLExtensions.def

71

Well to be honest nothing seems to need pragma but we have to accept it for the backward compatibility. :)

In case of the core features if pragma would have been useful we would have to still accept it for the backward compatibility even if the feature became core.

clang/lib/Parse/ParsePragma.cpp

785

It is a bit twisty here to be honest. Because we have also introduced the pragma begin and end that would add pragma enable/disable by default. So any extension added dynamically using begin/end would have to accept the pragma enable/disable.

https://clang.llvm.org/docs/UsersManual.html#opencl-extensions

But in the subsequent patches, I hope to remove this because I just don't see where it is useful but it is very confusing.

clang/test/SemaOpenCL/extension-version.cl

217

First of all with current approach, clang will only provide the diagnostic if an extra warning flag is passed. By default it accepts the pragma silently.

Secondly, to provide consistency clang will either need to know all of the features in the standard even if they are added in the libraries or otherwise, it will provide inconsistent diagnostics - for features added into clang we provide this diagnostic but for the others, we provide the diagnostics that you refer to. I appreciate that we already have the behavior very inconsistent but it is not great.

Another aspect is that the diagnostic we have currently indicates that the pragma is somehow legal (known) and might do something but in fact we never intended it to exist and never intended that frontend would do something with it. So I prefer to have consistency here with the regular diagnostics about the pragmas and indicate that the pragma is unknown. This just makes things simpler for everyone and avoids redundancy in the language too.

FYI this change is generally driving towards deprecation of the extension pragmas overall.

[azabaznov]

clang/include/clang/Basic/OpenCLExtensions.def

71

I'm just wondering if this new field needed in the file to maintain backward compatibility. Maybe we can highlight OpenCL C 3.0 features with some other way? Is it seems that check for name starting with "__opencl_c" is a bad idea?

clang/lib/Parse/ParsePragma.cpp

785

Is it ok not to track this situation here:

#pragma OPENCL EXTENSION __opencl_c_feature : begin
#pragma OPENCL EXTENSION __opencl_c_feature: end

This is some of a corner case, but still...

[Anastasia]

clang/include/clang/Basic/OpenCLExtensions.def

71

Not sure I understand you here but I don't think that we should add extension pragmas any longer at all even for the new extensions. FYI I am planning to add guidelines for that in https://reviews.llvm.org/D97072. Maybe it helps to clarify the idea?

clang/lib/Parse/ParsePragma.cpp

785

I see. I am not sure what should happen here - I guess we should give an error? Although for earlier versions than OpenCL 3.0 this should probably be accepted?

Perhaps we can create a PR for this for now...

[Anastasia]

Fixed typo and extra space.

[mantognini]

Some relatively minor comments, overall direction seems good to me.

clang/include/clang/Basic/OpenCLOptions.h

67–70

In OpenCLExtensions.def, the order is: pragma, avail, core, opt.
In this class it is: avail, core, opt, pragma (for both the attributes and the constructor parameters).

There are very few usages of this, so the impact of this inconsistency is minor. However, because the conversion between unsigned and bool is implicit an error might go unnoticed for a long time.

clang/lib/Basic/OpenCLOptions.cpp

89–91

This could be done using insert_or_assign(key, value).

clang/lib/Basic/Targets.cpp

738

For consistency with OpenCLExtensions.def.

[azabaznov]

clang/include/clang/Basic/OpenCLExtensions.def

71

I mean that you could modify OpenCLOptions::isWithPragma that it will check if extension/feature was introduced in OpenCL C 3.0. If that's the case then no pragma needed. This new field pragma looks redundant as it is set to true only for OpenCL C 3.0 features. However, it may be more cosmetic concern...

clang/lib/Parse/ParsePragma.cpp

785

Oh, I think we can ignore this as double underscored identifiers are reserved. It's not expected that users will declare new features.

[azabaznov]

I see the update regaring this functionality on github issue: https://github.com/KhronosGroup/OpenCL-Docs/issues/82#issuecomment-785496025. Is it a right way to reflect this information in`OpenCLExtensions.def`?

[Anastasia]

• Reorder fields,
• make constructor parameters explicit
• use insert_or_assign member of StringMap.

[Anastasia]

In D97052#2587043, @azabaznov wrote:

I see the update regaring this functionality on github issue: https://github.com/KhronosGroup/OpenCL-Docs/issues/82#issuecomment-785496025. Is it a right way to reflect this information in`OpenCLExtensions.def`?

The update only suggests a possible route and I don't want to block on it until there is a final decision. But if that becomes final, it is unlikely we will do something different. All the legacy pragmas will need to be accepted anyway.

clang/include/clang/Basic/OpenCLExtensions.def

71

You are right that it is only set to true for the OpenCL 3.0 features right now but the idea is to provide flexibility to set the pragma for every new extension/feature being added in the future instead of always adding the pragma unconditionally. This is why (I presume) we ended up with pragma for every extension in the first place. No matter that half of them were not used at all.

Also, there is nothing fundamentally different between extensions and features. The difference is purely wording in the spec. So I prefer us to use the same mechanisms for both.

clang/lib/Parse/ParsePragma.cpp

785

Yes, I think this is mainly used by tool developers.

[azabaznov]

Thanks for working on this. LGTM in general. I'll let Marco comment on the latest changes.

[Anastasia]

Reuploaded with changes from the 1st review round.

[mantognini]

LGTM, thanks for the update.

clang/include/clang/Basic/OpenCLExtensions.def

 //===----------------------------------------------------------------------===//
 
 // Macro OPENCLEXTNAME or OPENCL_GENERIC_EXTENSION can be defined to enumerate all
 // OpenCL extensions listed in this file.
 //
 // If extensions are to be enumerated with information about whether
 // an extension is core or optional core and minimum OpenCL version
 // when an extension becomes available,
-// define OPENCL_GENERIC_EXTENSION(ext, avail, core, opt) where
+// define OPENCL_GENERIC_EXTENSION(ext, pragma, avail, core, opt) where
 //   ext - name of the extension or optional core feature.
+//   pragma - true if extension needs pragmas or false otherwise.
+//            NOTE: extension pragma without any documentation detailing
+//            its behavior explicitly is deprecated. Therefore the default
+//            value if false.
 //   avail - minimum OpenCL version supporting it.
 //   core - OpenCL versions mask when the extension becomes core feature.
 //          0U indicates not a core feature.
 //   opt - OpenCL versions mask when the extension becomes optional core
 //         feature. 0U indicates not a optional core feature.
 //
 // If extensions are to be enumerated without any information,
 // define OPENCLEXTNAME(ext) where ext is the name of the extension.

 #ifndef OPENCLEXTNAME
 #pragma error "macro OPENCLEXTNAME or OPENCL_GENERIC_EXTENSION is required"
 #else
 #define OPENCL_GENERIC_EXTENSION(ext, ...) OPENCLEXTNAME(ext)
 #endif // OPENCLEXTNAME
 #endif // OPENCL_GENERIC_EXTENSION
 
 // Declaration helpers
-#define OPENCL_EXTENSION(ext, avail) OPENCL_GENERIC_EXTENSION(ext, avail, 0U, 0U)
-#define OPENCL_COREFEATURE(ext, avail, core)  OPENCL_GENERIC_EXTENSION(ext, avail, core, 0U)
-#define OPENCL_OPTIONALCOREFEATURE(ext, avail, opt) OPENCL_GENERIC_EXTENSION(ext, avail, 0U, opt)
+#define OPENCL_EXTENSION(ext, pragma, avail) OPENCL_GENERIC_EXTENSION(ext, pragma, avail, 0U, 0U)
+#define OPENCL_COREFEATURE(ext, pragma, avail, core)  OPENCL_GENERIC_EXTENSION(ext, pragma, avail, core, 0U)
+#define OPENCL_OPTIONALCOREFEATURE(ext, pragma, avail, opt) OPENCL_GENERIC_EXTENSION(ext, pragma, avail, 0U, opt)
 
 // OpenCL 1.0.
-OPENCL_COREFEATURE(cl_khr_byte_addressable_store, 100, OCL_C_11P)
-OPENCL_COREFEATURE(cl_khr_global_int32_base_atomics, 100, OCL_C_11P)
-OPENCL_COREFEATURE(cl_khr_global_int32_extended_atomics, 100, OCL_C_11P)
-OPENCL_COREFEATURE(cl_khr_local_int32_base_atomics, 100, OCL_C_11P)
-OPENCL_COREFEATURE(cl_khr_local_int32_extended_atomics, 100, OCL_C_11P)
-OPENCL_OPTIONALCOREFEATURE(cl_khr_fp64, 100, OCL_C_12P)
-OPENCL_EXTENSION(cl_khr_fp16, 100)
-OPENCL_EXTENSION(cl_khr_int64_base_atomics, 100)
-OPENCL_EXTENSION(cl_khr_int64_extended_atomics, 100)
-OPENCL_COREFEATURE(cl_khr_3d_image_writes, 100, OCL_C_20)
+OPENCL_COREFEATURE(cl_khr_byte_addressable_store, true, 100, OCL_C_11P)
+OPENCL_COREFEATURE(cl_khr_global_int32_base_atomics, true, 100, OCL_C_11P)
+OPENCL_COREFEATURE(cl_khr_global_int32_extended_atomics, true, 100, OCL_C_11P)
+OPENCL_COREFEATURE(cl_khr_local_int32_base_atomics, true, 100,  OCL_C_11P)
+OPENCL_COREFEATURE(cl_khr_local_int32_extended_atomics, true, 100, OCL_C_11P)
+OPENCL_OPTIONALCOREFEATURE(cl_khr_fp64, true, 100, OCL_C_12P)
+OPENCL_EXTENSION(cl_khr_fp16, true, 100)
+OPENCL_EXTENSION(cl_khr_int64_base_atomics, true, 100)
+OPENCL_EXTENSION(cl_khr_int64_extended_atomics, true, 100)
+OPENCL_COREFEATURE(cl_khr_3d_image_writes, true, 100, OCL_C_20)
 
 // EMBEDDED_PROFILE
-OPENCL_EXTENSION(cles_khr_int64, 110)
+OPENCL_EXTENSION(cles_khr_int64, true, 110)
 
 // OpenCL 1.2.
-OPENCL_EXTENSION(cl_khr_depth_images, 120)
-OPENCL_EXTENSION(cl_khr_gl_msaa_sharing, 120)
+OPENCL_EXTENSION(cl_khr_depth_images, true, 120)
+OPENCL_EXTENSION(cl_khr_gl_msaa_sharing,true, 120)
 
 // OpenCL 2.0.
-OPENCL_EXTENSION(cl_khr_mipmap_image, 200)
-OPENCL_EXTENSION(cl_khr_mipmap_image_writes, 200)
-OPENCL_EXTENSION(cl_khr_srgb_image_writes, 200)
-OPENCL_EXTENSION(cl_khr_subgroups, 200)
+OPENCL_EXTENSION(cl_khr_mipmap_image, true, 200)
+OPENCL_EXTENSION(cl_khr_mipmap_image_writes, true, 200)
+OPENCL_EXTENSION(cl_khr_srgb_image_writes, true, 200)
+OPENCL_EXTENSION(cl_khr_subgroups, true, 200)
 
 // Clang Extensions.
-OPENCL_EXTENSION(cl_clang_storage_class_specifiers, 100)
-OPENCL_EXTENSION(__cl_clang_function_pointers, 100)
-OPENCL_EXTENSION(__cl_clang_variadic_functions, 100)
+OPENCL_EXTENSION(cl_clang_storage_class_specifiers, true, 100)
+OPENCL_EXTENSION(__cl_clang_function_pointers, true, 100)
+OPENCL_EXTENSION(__cl_clang_variadic_functions, true, 100)
 
 // AMD OpenCL extensions
-OPENCL_EXTENSION(cl_amd_media_ops, 100)
-OPENCL_EXTENSION(cl_amd_media_ops2, 100)
+OPENCL_EXTENSION(cl_amd_media_ops, true, 100)
+OPENCL_EXTENSION(cl_amd_media_ops2, true, 100)
 
 // ARM OpenCL extensions
-OPENCL_EXTENSION(cl_arm_integer_dot_product_int8, 120)
-OPENCL_EXTENSION(cl_arm_integer_dot_product_accumulate_int8, 120)
-OPENCL_EXTENSION(cl_arm_integer_dot_product_accumulate_int16, 120)
-OPENCL_EXTENSION(cl_arm_integer_dot_product_accumulate_saturate_int8, 120)
+OPENCL_EXTENSION(cl_arm_integer_dot_product_int8, true, 120)
+OPENCL_EXTENSION(cl_arm_integer_dot_product_accumulate_int8, true, 120)
+OPENCL_EXTENSION(cl_arm_integer_dot_product_accumulate_int16, true, 120)
+OPENCL_EXTENSION(cl_arm_integer_dot_product_accumulate_saturate_int8, true, 120)
 
 // Intel OpenCL extensions
-OPENCL_EXTENSION(cl_intel_subgroups, 120)
-OPENCL_EXTENSION(cl_intel_subgroups_short, 120)
-OPENCL_EXTENSION(cl_intel_device_side_avc_motion_estimation, 120)
+OPENCL_EXTENSION(cl_intel_subgroups, true, 120)
+OPENCL_EXTENSION(cl_intel_subgroups_short, true, 120)
+OPENCL_EXTENSION(cl_intel_device_side_avc_motion_estimation, true, 120)
 
 // OpenCL C 3.0 features (6.2.1. Features)
-OPENCL_OPTIONALCOREFEATURE(__opencl_c_pipes, 300, OCL_C_30)
-OPENCL_OPTIONALCOREFEATURE(__opencl_c_generic_address_space, 300, OCL_C_30)
-OPENCL_OPTIONALCOREFEATURE(__opencl_c_atomic_order_acq_rel, 300, OCL_C_30)
-OPENCL_OPTIONALCOREFEATURE(__opencl_c_atomic_order_seq_cst, 300, OCL_C_30)
-OPENCL_OPTIONALCOREFEATURE(__opencl_c_subgroups, 300, OCL_C_30)
-OPENCL_OPTIONALCOREFEATURE(__opencl_c_3d_image_writes, 300, OCL_C_30)
-OPENCL_OPTIONALCOREFEATURE(__opencl_c_device_enqueue, 300, OCL_C_30)
-OPENCL_OPTIONALCOREFEATURE(__opencl_c_read_write_images, 300, OCL_C_30)
-OPENCL_OPTIONALCOREFEATURE(__opencl_c_program_scope_global_variables, 300, OCL_C_30)
-OPENCL_OPTIONALCOREFEATURE(__opencl_c_fp64, 300, OCL_C_30)
-OPENCL_OPTIONALCOREFEATURE(__opencl_c_images, 300, OCL_C_30)
+OPENCL_OPTIONALCOREFEATURE(__opencl_c_pipes, false, 300, OCL_C_30)
+OPENCL_OPTIONALCOREFEATURE(__opencl_c_generic_address_space, false, 300, OCL_C_30)
+OPENCL_OPTIONALCOREFEATURE(__opencl_c_atomic_order_acq_rel, false, 300, OCL_C_30)
+OPENCL_OPTIONALCOREFEATURE(__opencl_c_atomic_order_seq_cst, false, 300, OCL_C_30)
+OPENCL_OPTIONALCOREFEATURE(__opencl_c_subgroups, false, 300, OCL_C_30)
+OPENCL_OPTIONALCOREFEATURE(__opencl_c_3d_image_writes, false, 300, OCL_C_30)
+OPENCL_OPTIONALCOREFEATURE(__opencl_c_device_enqueue, false, 300, OCL_C_30)
+OPENCL_OPTIONALCOREFEATURE(__opencl_c_read_write_images, false, 300, OCL_C_30)
+OPENCL_OPTIONALCOREFEATURE(__opencl_c_program_scope_global_variables, false, 300, OCL_C_30)
+OPENCL_OPTIONALCOREFEATURE(__opencl_c_fp64, false, 300, OCL_C_30)
+OPENCL_OPTIONALCOREFEATURE(__opencl_c_images, false, 300, OCL_C_30)
 
 #undef OPENCL_OPTIONALCOREFEATURE
 #undef OPENCL_COREFEATURE
 #undef OPENCL_GENERIC_EXTENSION
 
 #ifdef OPENCLEXTNAME
 #undef OPENCLEXTNAME
 #endif

clang/include/clang/Basic/OpenCLOptions.h

static inline bool isOpenCLVersionIsContainedInMask(const LangOptions &LO,
   OpenCLVersionID Code = encodeOpenCLVersion(CLVer);
   return Mask & Code;
 }
 } // end anonymous namespace
 
 /// OpenCL supported extensions and optional core features
 class OpenCLOptions {
 public:
   struct OpenCLOptionInfo {
+    // Does this option have pragma.
+    bool WithPragma = false;
+
     // Option starts to be available in this OpenCL version
-    unsigned Avail;
+    unsigned Avail = 100U;
 
     // Option becomes core feature in this OpenCL versions
-    unsigned Core;
+    unsigned Core = 0U;
 
     // Option becomes optional core feature in this OpenCL versions
-    unsigned Opt;
+    unsigned Opt = 0U;
 
     // Is this option supported
     bool Supported = false;
 
     // Is this option enabled
     bool Enabled = false;
 
-    OpenCLOptionInfo(unsigned A = 100, unsigned C = 0U, unsigned O = 0U)
-        : Avail(A), Core(C), Opt(O) {}
+    OpenCLOptionInfo() = default;
+    OpenCLOptionInfo(bool Pragma, unsigned AvailV, unsigned CoreV,
+                     unsigned OptV)
+        : WithPragma(Pragma), Avail(AvailV), Core(CoreV), Opt(OptV) {}
 
     bool isCore() const { return Core != 0U; }
 
     bool isOptionalCore() const { return Opt != 0U; }
 
     // Is option available in OpenCL version \p LO.
     bool isAvailableIn(const LangOptions &LO) const {
       // In C++ mode all extensions should work at least as in v2.0.
bool isOptionalCoreIn(const LangOptions &LO) const {
       return isAvailableIn(LO) && isOpenCLVersionIsContainedInMask(LO, Opt);
     }
   };
 
   bool isKnown(llvm::StringRef Ext) const;
 
   bool isEnabled(llvm::StringRef Ext) const;
 
+  bool isWithPragma(llvm::StringRef Ext) const;
+
   // Is supported as either an extension or an (optional) core feature for
   // OpenCL version \p LO.
   bool isSupported(llvm::StringRef Ext, const LangOptions &LO) const;
 
   // Is supported OpenCL core feature for OpenCL version \p LO.
   // For supported extension, return false.
   bool isSupportedCore(llvm::StringRef Ext, const LangOptions &LO) const;
 
   // Is supported optional core OpenCL feature for OpenCL version \p LO.
   // For supported extension, return false.
   bool isSupportedOptionalCore(llvm::StringRef Ext,
                                const LangOptions &LO) const;
 
   // Is supported optional core or core OpenCL feature for OpenCL version \p
   // LO. For supported extension, return false.
   bool isSupportedCoreOrOptionalCore(llvm::StringRef Ext,
                                      const LangOptions &LO) const;
 
   // Is supported OpenCL extension for OpenCL version \p LO.
   // For supported core or optional core feature, return false.
   bool isSupportedExtension(llvm::StringRef Ext, const LangOptions &LO) const;
 
+  // FIXME: Whether extension should accept pragma should not
+  // be reset dynamically. But it currently required when
+  // registering new extensions via pragmas.
+  void acceptsPragma(llvm::StringRef Ext, bool V = true);
+
   void enable(llvm::StringRef Ext, bool V = true);
 
   /// Enable or disable support for OpenCL extensions
   /// \param Ext name of the extension (not prefixed with '+' or '-')
   /// \param V value to set for a extension
   void support(llvm::StringRef Ext, bool V = true);
 
   OpenCLOptions();

clang/lib/Basic/OpenCLOptions.cpp

bool OpenCLOptions::isKnown(llvm::StringRef Ext) const {
   return OptMap.find(Ext) != OptMap.end();
 }
 
 bool OpenCLOptions::isEnabled(llvm::StringRef Ext) const {
   auto E = OptMap.find(Ext);
   return E != OptMap.end() && E->second.Enabled;
 }
 
+bool OpenCLOptions::isWithPragma(llvm::StringRef Ext) const {
+  auto E = OptMap.find(Ext);
+  return E != OptMap.end() && E->second.WithPragma;
+}
+
 bool OpenCLOptions::isSupported(llvm::StringRef Ext,
                                 const LangOptions &LO) const {
   auto E = OptMap.find(Ext);
   if (E == OptMap.end()) {
     return false;
   }
   auto I = OptMap.find(Ext)->getValue();
   return I.Supported && I.isAvailableIn(LO);
bool OpenCLOptions::isSupportedExtension(llvm::StringRef Ext,
   return I.Supported && I.isAvailableIn(LO) &&
          !isSupportedCoreOrOptionalCore(Ext, LO);
 }
 
 void OpenCLOptions::enable(llvm::StringRef Ext, bool V) {
   OptMap[Ext].Enabled = V;
 }
 
+void OpenCLOptions::acceptsPragma(llvm::StringRef Ext, bool V) {
+  OptMap[Ext].WithPragma = V;
+}
+
 void OpenCLOptions::support(llvm::StringRef Ext, bool V) {
   assert(!Ext.empty() && "Extension is empty.");
   assert(Ext[0] != '+' && Ext[0] != '-');
   OptMap[Ext].Supported = V;
 }
 
 OpenCLOptions::OpenCLOptions() {
-#define OPENCL_GENERIC_EXTENSION(Ext, AvailVer, CoreVer, OptVer)               \
-  OptMap[#Ext].Avail = AvailVer;                                               \
-  OptMap[#Ext].Core = CoreVer;                                                 \
-  OptMap[#Ext].Opt = OptVer;
+#define OPENCL_GENERIC_EXTENSION(Ext, WithPragma, AvailVer, CoreVer, OptVer)   \
+  OptMap.insert_or_assign(                                                     \
+      #Ext, OpenCLOptionInfo{WithPragma, AvailVer, CoreVer, OptVer});
 #include "clang/Basic/OpenCLExtensions.def"
 }
 
 void OpenCLOptions::addSupport(const llvm::StringMap<bool> &FeaturesMap,
                                const LangOptions &Opts) {
   for (const auto &F : FeaturesMap) {
     const auto &Name = F.getKey();
     if (F.getValue() && isKnown(Name) && OptMap[Name].isAvailableIn(Opts))
       support(Name);

clang/lib/Basic/Targets.cpp

 }
 
 /// getOpenCLFeatureDefines - Define OpenCL macros based on target settings
 /// and language version
 void TargetInfo::getOpenCLFeatureDefines(const LangOptions &Opts,
                                          MacroBuilder &Builder) const {
   // FIXME: OpenCL options which affect language semantics/syntax
   // should be moved into LangOptions, thus macro definitions of
-  // such options is better to be done in clang::InitializePreprocessor
+  // such options is better to be done in clang::InitializePreprocessor.
   auto defineOpenCLExtMacro = [&](llvm::StringRef Name, unsigned AvailVer,
                                   unsigned CoreVersions,
                                   unsigned OptionalVersions) {
     // Check if extension is supported by target and is available in this
     // OpenCL version
     auto It = getTargetOpts().OpenCLFeaturesMap.find(Name);
     if ((It != getTargetOpts().OpenCLFeaturesMap.end()) && It->getValue() &&
-        OpenCLOptions::OpenCLOptionInfo(AvailVer, CoreVersions,
+        OpenCLOptions::OpenCLOptionInfo(false, AvailVer, CoreVersions,
                                         OptionalVersions)
             .isAvailableIn(Opts))
       Builder.defineMacro(Name);
   };
-#define OPENCL_GENERIC_EXTENSION(Ext, Avail, Core, Opt)                        \
+#define OPENCL_GENERIC_EXTENSION(Ext, WithPragma, Avail, Core, Opt)            \
   defineOpenCLExtMacro(#Ext, Avail, Core, Opt);
 #include "clang/Basic/OpenCLExtensions.def"
 
   // Assume compiling for FULL profile
   Builder.defineMacro("__opencl_c_int64");
 }

clang/lib/Parse/ParsePragma.cpp

if (State == Disable) {
       Opt.disableAll();
       Opt.enableSupportedCore(getLangOpts());
     } else {
       PP.Diag(NameLoc, diag::warn_pragma_expected_predicate) << 1;
     }
   } else if (State == Begin) {
     if (!Opt.isKnown(Name) || !Opt.isSupported(Name, getLangOpts())) {
       Opt.support(Name);
+      // FIXME: Default behavior of the extension pragma is not defined.
+      // Therefore, it should never be added by default.
+      Opt.acceptsPragma(Name);
     }
     Actions.setCurrentOpenCLExtension(Name);
   } else if (State == End) {
     if (Name != Actions.getCurrentOpenCLExtension())
       PP.Diag(NameLoc, diag::warn_pragma_begin_end_mismatch);
     Actions.setCurrentOpenCLExtension("");
-  } else if (!Opt.isKnown(Name))
+  } else if (!Opt.isKnown(Name) || !Opt.isWithPragma(Name))
     PP.Diag(NameLoc, diag::warn_pragma_unknown_extension) << Ident;
   else if (Opt.isSupportedExtension(Name, getLangOpts()))
     Opt.enable(Name, State == Enable);
   else if (Opt.isSupportedCoreOrOptionalCore(Name, getLangOpts()))
     PP.Diag(NameLoc, diag::warn_pragma_extension_is_core) << Ident;
   else
     PP.Diag(NameLoc, diag::warn_pragma_unsupported_extension) << Ident;
 }

clang/lib/Serialization/ASTReader.cpp

case FP_PRAGMA_OPTIONS:
       break;
 
     case OPENCL_EXTENSIONS:
       for (unsigned I = 0, E = Record.size(); I != E; ) {
         auto Name = ReadString(Record, I);
         auto &OptInfo = OpenCLExtensions.OptMap[Name];
         OptInfo.Supported = Record[I++] != 0;
         OptInfo.Enabled = Record[I++] != 0;
+        OptInfo.WithPragma = Record[I++] != 0;
         OptInfo.Avail = Record[I++];
         OptInfo.Core = Record[I++];
         OptInfo.Opt = Record[I++];
       }
       break;
 
     case OPENCL_EXTENSION_TYPES:
       for (unsigned I = 0, E = Record.size(); I != E;) {

clang/lib/Serialization/ASTWriter.cpp

void ASTWriter::WriteOpenCLExtensions(Sema &SemaRef) {
 
   const OpenCLOptions &Opts = SemaRef.getOpenCLOptions();
   RecordData Record;
   for (const auto &I:Opts.OptMap) {
     AddString(I.getKey(), Record);
     auto V = I.getValue();
     Record.push_back(V.Supported ? 1 : 0);
     Record.push_back(V.Enabled ? 1 : 0);
+    Record.push_back(V.WithPragma ? 1 : 0);
     Record.push_back(V.Avail);
     Record.push_back(V.Core);
     Record.push_back(V.Opt);
   }
   Stream.EmitRecord(OPENCL_EXTENSIONS, Record);
 }
 
 void ASTWriter::WriteOpenCLExtensionTypes(Sema &SemaRef) {

clang/test/SemaOpenCL/extension-version.cl

 // RUN: %clang_cc1 -x cl -cl-std=CL %s -verify -triple spir-unknown-unknown
 // RUN: %clang_cc1 -x cl -cl-std=CL1.1 %s -verify -triple spir-unknown-unknown
 // RUN: %clang_cc1 -x cl -cl-std=CL1.2 %s -verify -triple spir-unknown-unknown
 // RUN: %clang_cc1 -x cl -cl-std=CL2.0 %s -verify -triple spir-unknown-unknown
 // RUN: %clang_cc1 -x cl -cl-std=clc++ %s -verify -triple spir-unknown-unknown
+// RUN: %clang_cc1 -x cl -cl-std=CL3.0 %s -verify -triple spir-unknown-unknown
 // RUN: %clang_cc1 -x cl -cl-std=CL %s -verify -triple spir-unknown-unknown -Wpedantic-core-features -DTEST_CORE_FEATURES
 // RUN: %clang_cc1 -x cl -cl-std=CL1.1 %s -verify -triple spir-unknown-unknown -Wpedantic-core-features -DTEST_CORE_FEATURES
 // RUN: %clang_cc1 -x cl -cl-std=CL1.2 %s -verify -triple spir-unknown-unknown -Wpedantic-core-features -DTEST_CORE_FEATURES
 // RUN: %clang_cc1 -x cl -cl-std=CL2.0 %s -verify -triple spir-unknown-unknown -Wpedantic-core-features -DTEST_CORE_FEATURES
 // RUN: %clang_cc1 -x cl -cl-std=clc++ %s -verify -triple spir-unknown-unknown -Wpedantic-core-features -DTEST_CORE_FEATURES
-
-#if (defined(__OPENCL_CPP_VERSION__) || __OPENCL_C_VERSION__ >= 200) && !defined(TEST_CORE_FEATURES)
-// expected-no-diagnostics
-#endif
+// RUN: %clang_cc1 -x cl -cl-std=CL3.0 %s -verify -triple spir-unknown-unknown -Wpedantic-core-features -DTEST_CORE_FEATURES
 
 // Extensions in all versions
 #ifndef cl_clang_storage_class_specifiers
 #error "Missing cl_clang_storage_class_specifiers define"
 #endif
 #pragma OPENCL EXTENSION cl_clang_storage_class_specifiers : enable
 
 #ifndef __cl_clang_function_pointers

 // expected-warning@-2{{OpenCL extension 'cl_khr_fp64' is core feature or supported optional core feature - ignoring}}
 #endif
 
 //Core feature in CL 2.0
 #ifndef cl_khr_3d_image_writes
 #error "Missing cl_khr_3d_image_writes define"
 #endif
 #pragma OPENCL EXTENSION cl_khr_3d_image_writes : enable
-#if (defined(__OPENCL_CPP_VERSION__) || __OPENCL_C_VERSION__ >= 200) && defined TEST_CORE_FEATURES
+#if (defined(__OPENCL_CPP_VERSION__) || __OPENCL_C_VERSION__ == 200) && defined TEST_CORE_FEATURES
 // expected-warning@-2{{OpenCL extension 'cl_khr_3d_image_writes' is core feature or supported optional core feature - ignoring}}
 #endif
 
 #if (defined(__OPENCL_CPP_VERSION__) || __OPENCL_C_VERSION__ >= 110)
 #ifndef cles_khr_int64
 #error "Missing cles_khr_int64 define"
 #endif
 #else

 #if (defined(__OPENCL_CPP_VERSION__) || __OPENCL_C_VERSION__ >= 120)
 #ifndef cl_intel_device_side_avc_motion_estimation
 #error "Missing cl_intel_device_side_avc_motion_estimation define"
 #endif
 #else
 // expected-warning@+2{{unsupported OpenCL extension 'cl_intel_device_side_avc_motion_estimation' - ignoring}}
 #endif
 #pragma OPENCL EXTENSION cl_intel_device_side_avc_motion_estimation : enable
+
+// Check that pragmas for the OpenCL 3.0 features are rejected.
+
+#pragma OPENCL EXTENSION __opencl_c_int64 : disable
+//expected-warning@-1{{unknown OpenCL extension '__opencl_c_int64' - ignoring}}
+#pragma OPENCL EXTENSION __opencl_c_3d_image_writes : disable
+//expected-warning@-1{{unknown OpenCL extension '__opencl_c_3d_image_writes' - ignoring}}
+#pragma OPENCL EXTENSION __opencl_c_atomic_order_acq_rel : disable
+//expected-warning@-1{{unknown OpenCL extension '__opencl_c_atomic_order_acq_rel' - ignoring}}
+#pragma OPENCL EXTENSION __opencl_c_atomic_order_seq_cst : disable
+//expected-warning@-1{{unknown OpenCL extension '__opencl_c_atomic_order_seq_cst' - ignoring}}
+#pragma OPENCL EXTENSION __opencl_c_device_enqueue : disable
+//expected-warning@-1{{unknown OpenCL extension '__opencl_c_device_enqueue' - ignoring}}
+#pragma OPENCL EXTENSION __opencl_c_fp64 : disable
+//expected-warning@-1{{unknown OpenCL extension '__opencl_c_fp64' - ignoring}}
+#pragma OPENCL EXTENSION __opencl_c_generic_address_space : disable
+//expected-warning@-1{{unknown OpenCL extension '__opencl_c_generic_address_space' - ignoring}}
+#pragma OPENCL EXTENSION __opencl_c_images : disable
+//expected-warning@-1{{unknown OpenCL extension '__opencl_c_images' - ignoring}}
+#pragma OPENCL EXTENSION __opencl_c_pipes : disable
+//expected-warning@-1{{unknown OpenCL extension '__opencl_c_pipes' - ignoring}}
+#pragma OPENCL EXTENSION __opencl_c_program_scope_global_variables : disable
+//expected-warning@-1{{unknown OpenCL extension '__opencl_c_program_scope_global_variables' - ignoring}}
+#pragma OPENCL EXTENSION __opencl_c_read_write_images : disable
+//expected-warning@-1{{unknown OpenCL extension '__opencl_c_read_write_images' - ignoring}}
+#pragma OPENCL EXTENSION __opencl_c_subgroups : disable
+//expected-warning@-1{{unknown OpenCL extension '__opencl_c_subgroups' - ignoring}}
+
+#pragma OPENCL EXTENSION __opencl_c_int64 : enable
+//expected-warning@-1{{unknown OpenCL extension '__opencl_c_int64' - ignoring}}
+#pragma OPENCL EXTENSION __opencl_c_3d_image_writes : enable
+//expected-warning@-1{{unknown OpenCL extension '__opencl_c_3d_image_writes' - ignoring}}
+#pragma OPENCL EXTENSION __opencl_c_atomic_order_acq_rel : enable
+//expected-warning@-1{{unknown OpenCL extension '__opencl_c_atomic_order_acq_rel' - ignoring}}
+#pragma OPENCL EXTENSION __opencl_c_atomic_order_seq_cst : enable
+//expected-warning@-1{{unknown OpenCL extension '__opencl_c_atomic_order_seq_cst' - ignoring}}
+#pragma OPENCL EXTENSION __opencl_c_device_enqueue : enable
+//expected-warning@-1{{unknown OpenCL extension '__opencl_c_device_enqueue' - ignoring}}
+#pragma OPENCL EXTENSION __opencl_c_fp64 : enable
+//expected-warning@-1{{unknown OpenCL extension '__opencl_c_fp64' - ignoring}}
+#pragma OPENCL EXTENSION __opencl_c_generic_address_space : enable
+//expected-warning@-1{{unknown OpenCL extension '__opencl_c_generic_address_space' - ignoring}}
+#pragma OPENCL EXTENSION __opencl_c_images : enable
+//expected-warning@-1{{unknown OpenCL extension '__opencl_c_images' - ignoring}}
+#pragma OPENCL EXTENSION __opencl_c_pipes : enable
+//expected-warning@-1{{unknown OpenCL extension '__opencl_c_pipes' - ignoring}}
+#pragma OPENCL EXTENSION __opencl_c_program_scope_global_variables : enable
+//expected-warning@-1{{unknown OpenCL extension '__opencl_c_program_scope_global_variables' - ignoring}}
+#pragma OPENCL EXTENSION __opencl_c_read_write_images : enable
+//expected-warning@-1{{unknown OpenCL extension '__opencl_c_read_write_images' - ignoring}}
+#pragma OPENCL EXTENSION __opencl_c_subgroups : enable
+//expected-warning@-1{{unknown OpenCL extension '__opencl_c_subgroups' - ignoring}}