[OpenCL] Reword unknown extension pragma diagnostic

[svenvh]

Summary

For newer OpenCL extensions that do not require a pragma, such as
cl_khr_subgroup_shuffle, a user could still accidentally attempt to
use a pragma. This would result in a warning

"unknown OpenCL extension 'cl_khr_subgroup_shuffle' - ignoring"

which could be mistakenly interpreted as "Clang does not support this
extension at all" instead of "Clang does not require any pragma for
this extension".

[Anastasia]

Ok, makes sense! Thanks!

Btw I was thinking we should provide some way for developers to know what extensions are being supported either through documentation or by querying clang somehow? I am guessing documentation would be easier to implement but harder to keep in sync?

[svenvh]

In D126660#3550356, @Anastasia wrote:

Ok, makes sense! Thanks!

Btw I was thinking we should provide some way for developers to know what extensions are being supported either through documentation or by querying clang somehow? I am guessing documentation would be easier to implement but harder to keep in sync?

I agree that would be nice to have. That would also enable us to distinguish valid pragmaless extensions from garbage (e.g. mistyped extensions), and would also help -cl-ext parsing/diagnosing for example. But that would require us to maintain a list of extensions inside Clang, which I believe is what we wanted to move away from (especially for extensions that only add library-like functionality)?

clang/include/clang/Basic/DiagnosticParseKinds.td

def warn_no_support_for_eval_method_source_on_m32 : Warning<
   " without SSE is not supported.">, InGroup<Pragmas>;
 
 // OpenCL EXTENSION pragma (OpenCL 1.1 [9.1])
 def warn_pragma_expected_colon : Warning<
   "missing ':' after %0 - ignoring">, InGroup<IgnoredPragmas>;
 def warn_pragma_expected_predicate : Warning<
   "expected %select{'enable', 'disable', 'begin' or 'end'|'disable'}0 - ignoring">, InGroup<IgnoredPragmas>;
 def warn_pragma_unknown_extension : Warning<
-  "unknown OpenCL extension %0 - ignoring">, InGroup<IgnoredPragmas>;
+  "OpenCL extension %0 unknown or does not require pragma - ignoring">, InGroup<IgnoredPragmas>;
 def warn_pragma_unsupported_extension : Warning<
   "unsupported OpenCL extension %0 - ignoring">, InGroup<IgnoredPragmas>;
 def warn_pragma_extension_is_core : Warning<
   "OpenCL extension %0 is core feature or supported optional core feature - ignoring">,
   InGroup<OpenCLCoreFeaturesDiagGroup>, DefaultIgnore;
 
 // OpenCL errors.
 def err_opencl_taking_function_address_parser : Error<

clang/test/Headers/opencl-c-header.cl

 
 // For SPIR all extensions are supported.
 #if defined(__SPIR__) || defined(__SPIRV__)
 
 // Verify that cl_intel_planar_yuv extension is defined from OpenCL 1.2 onwards.
 #if defined(__OPENCL_CPP_VERSION__) || (__OPENCL_C_VERSION__ >= CL_VERSION_1_2)
 // expected-no-diagnostics
 #else //__OPENCL_C_VERSION__
-// expected-warning@+2{{unknown OpenCL extension 'cl_intel_planar_yuv' - ignoring}}
+// expected-warning@+2{{OpenCL extension 'cl_intel_planar_yuv' unknown or does not require pragma - ignoring}}
 #endif //__OPENCL_C_VERSION__
 #pragma OPENCL EXTENSION cl_intel_planar_yuv : enable
 
 #if (defined(__OPENCL_CPP_VERSION__) || __OPENCL_C_VERSION__ >= 200)
 
 #if cl_khr_subgroup_extended_types != 1
 #error "Incorrectly defined cl_khr_subgroup_extended_types"
 #endif

clang/test/Parser/opencl-pragma.cl

 // RUN: %clang_cc1 %s -verify -pedantic -Wno-empty-translation-unit -fsyntax-only -triple spir-unknown-unknown
 
 #pragma OPENCL EXTENSION cl_khr_fp16 : enable
 
-#pragma OPENCL EXTENSION cl_no_such_extension : disable /* expected-warning {{unknown OpenCL extension 'cl_no_such_extension' - ignoring}} */
+#pragma OPENCL EXTENSION cl_no_such_extension : disable /* expected-warning {{OpenCL extension 'cl_no_such_extension' unknown or does not require pragma - ignoring}} */
 
 #pragma OPENCL EXTENSION all : disable
 #pragma OPENCL EXTENSION all : enable /* expected-warning {{expected 'disable' - ignoring}} */
 
 #pragma OPENCL EXTENSION cl_khr_fp64 : on /* expected-warning {{expected 'enable', 'disable', 'begin' or 'end' - ignoring}} */
 
 #pragma OPENCL FP_CONTRACT ON
 #pragma OPENCL FP_CONTRACT OFF
 #pragma OPENCL FP_CONTRACT DEFAULT
 #pragma OPENCL FP_CONTRACT FOO // expected-warning {{expected 'ON' or 'OFF' or 'DEFAULT' in pragma}}

clang/test/SemaOpenCL/extension-begin.cl

 //
 // RUN: rm -rf %t.modules
 // RUN: mkdir -p %t.modules
 //
 // RUN: %clang_cc1 -cl-std=CL2.0 -DIMPLICIT_INCLUDE -include %S/extension-begin.h -triple spir-unknown-unknown -O0 -emit-llvm -o - -fmodules -fimplicit-module-maps -fmodules-cache-path=%t.modules %s -verify -pedantic
 
 #pragma OPENCL EXTENSION my_ext : enable
 #ifndef IMPLICIT_INCLUDE
-// expected-warning@-2 {{unknown OpenCL extension 'my_ext' - ignoring}}
-// expected-warning@+2 {{unknown OpenCL extension 'my_ext' - ignoring}}
+// expected-warning@-2 {{OpenCL extension 'my_ext' unknown or does not require pragma - ignoring}}
+// expected-warning@+2 {{OpenCL extension 'my_ext' unknown or does not require pragma - ignoring}}
 #endif // IMPLICIT_INCLUDE
 #pragma OPENCL EXTENSION my_ext : disable
 
 #ifndef IMPLICIT_INCLUDE
 #include "extension-begin.h"
 #endif // IMPLICIT_INCLUDE
 #ifndef USE_PCH
 // expected-warning@extension-begin.h:4 {{expected 'disable' - ignoring}}

clang/test/SemaOpenCL/extension-version.cl

 #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}}
+//expected-warning@-1{{OpenCL extension '__opencl_c_int64' unknown or does not require pragma - ignoring}}
 #pragma OPENCL EXTENSION __opencl_c_3d_image_writes : disable
-//expected-warning@-1{{unknown OpenCL extension '__opencl_c_3d_image_writes' - ignoring}}
+//expected-warning@-1{{OpenCL extension '__opencl_c_3d_image_writes' unknown or does not require pragma - ignoring}}
 #pragma OPENCL EXTENSION __opencl_c_atomic_order_acq_rel : disable
-//expected-warning@-1{{unknown OpenCL extension '__opencl_c_atomic_order_acq_rel' - ignoring}}
+//expected-warning@-1{{OpenCL extension '__opencl_c_atomic_order_acq_rel' unknown or does not require pragma - ignoring}}
 #pragma OPENCL EXTENSION __opencl_c_atomic_order_seq_cst : disable
-//expected-warning@-1{{unknown OpenCL extension '__opencl_c_atomic_order_seq_cst' - ignoring}}
+//expected-warning@-1{{OpenCL extension '__opencl_c_atomic_order_seq_cst' unknown or does not require pragma - ignoring}}
 #pragma OPENCL EXTENSION __opencl_c_device_enqueue : disable
-//expected-warning@-1{{unknown OpenCL extension '__opencl_c_device_enqueue' - ignoring}}
+//expected-warning@-1{{OpenCL extension '__opencl_c_device_enqueue' unknown or does not require pragma - ignoring}}
 #pragma OPENCL EXTENSION __opencl_c_fp64 : disable
-//expected-warning@-1{{unknown OpenCL extension '__opencl_c_fp64' - ignoring}}
+//expected-warning@-1{{OpenCL extension '__opencl_c_fp64' unknown or does not require pragma - ignoring}}
 #pragma OPENCL EXTENSION __opencl_c_generic_address_space : disable
-//expected-warning@-1{{unknown OpenCL extension '__opencl_c_generic_address_space' - ignoring}}
+//expected-warning@-1{{OpenCL extension '__opencl_c_generic_address_space' unknown or does not require pragma - ignoring}}
 #pragma OPENCL EXTENSION __opencl_c_images : disable
-//expected-warning@-1{{unknown OpenCL extension '__opencl_c_images' - ignoring}}
+//expected-warning@-1{{OpenCL extension '__opencl_c_images' unknown or does not require pragma - ignoring}}
 #pragma OPENCL EXTENSION __opencl_c_pipes : disable
-//expected-warning@-1{{unknown OpenCL extension '__opencl_c_pipes' - ignoring}}
+//expected-warning@-1{{OpenCL extension '__opencl_c_pipes' unknown or does not require pragma - ignoring}}
 #pragma OPENCL EXTENSION __opencl_c_program_scope_global_variables : disable
-//expected-warning@-1{{unknown OpenCL extension '__opencl_c_program_scope_global_variables' - ignoring}}
+//expected-warning@-1{{OpenCL extension '__opencl_c_program_scope_global_variables' unknown or does not require pragma - ignoring}}
 #pragma OPENCL EXTENSION __opencl_c_read_write_images : disable
-//expected-warning@-1{{unknown OpenCL extension '__opencl_c_read_write_images' - ignoring}}
+//expected-warning@-1{{OpenCL extension '__opencl_c_read_write_images' unknown or does not require pragma - ignoring}}
 #pragma OPENCL EXTENSION __opencl_c_subgroups : disable
-//expected-warning@-1{{unknown OpenCL extension '__opencl_c_subgroups' - ignoring}}
+//expected-warning@-1{{OpenCL extension '__opencl_c_subgroups' unknown or does not require pragma - ignoring}}
 
 #pragma OPENCL EXTENSION __opencl_c_int64 : enable
-//expected-warning@-1{{unknown OpenCL extension '__opencl_c_int64' - ignoring}}
+//expected-warning@-1{{OpenCL extension '__opencl_c_int64' unknown or does not require pragma - ignoring}}
 #pragma OPENCL EXTENSION __opencl_c_3d_image_writes : enable
-//expected-warning@-1{{unknown OpenCL extension '__opencl_c_3d_image_writes' - ignoring}}
+//expected-warning@-1{{OpenCL extension '__opencl_c_3d_image_writes' unknown or does not require pragma - ignoring}}
 #pragma OPENCL EXTENSION __opencl_c_atomic_order_acq_rel : enable
-//expected-warning@-1{{unknown OpenCL extension '__opencl_c_atomic_order_acq_rel' - ignoring}}
+//expected-warning@-1{{OpenCL extension '__opencl_c_atomic_order_acq_rel' unknown or does not require pragma - ignoring}}
 #pragma OPENCL EXTENSION __opencl_c_atomic_order_seq_cst : enable
-//expected-warning@-1{{unknown OpenCL extension '__opencl_c_atomic_order_seq_cst' - ignoring}}
+//expected-warning@-1{{OpenCL extension '__opencl_c_atomic_order_seq_cst' unknown or does not require pragma - ignoring}}
 #pragma OPENCL EXTENSION __opencl_c_device_enqueue : enable
-//expected-warning@-1{{unknown OpenCL extension '__opencl_c_device_enqueue' - ignoring}}
+//expected-warning@-1{{OpenCL extension '__opencl_c_device_enqueue' unknown or does not require pragma - ignoring}}
 #pragma OPENCL EXTENSION __opencl_c_fp64 : enable
-//expected-warning@-1{{unknown OpenCL extension '__opencl_c_fp64' - ignoring}}
+//expected-warning@-1{{OpenCL extension '__opencl_c_fp64' unknown or does not require pragma - ignoring}}
 #pragma OPENCL EXTENSION __opencl_c_generic_address_space : enable
-//expected-warning@-1{{unknown OpenCL extension '__opencl_c_generic_address_space' - ignoring}}
+//expected-warning@-1{{OpenCL extension '__opencl_c_generic_address_space' unknown or does not require pragma - ignoring}}
 #pragma OPENCL EXTENSION __opencl_c_images : enable
-//expected-warning@-1{{unknown OpenCL extension '__opencl_c_images' - ignoring}}
+//expected-warning@-1{{OpenCL extension '__opencl_c_images' unknown or does not require pragma - ignoring}}
 #pragma OPENCL EXTENSION __opencl_c_pipes : enable
-//expected-warning@-1{{unknown OpenCL extension '__opencl_c_pipes' - ignoring}}
+//expected-warning@-1{{OpenCL extension '__opencl_c_pipes' unknown or does not require pragma - ignoring}}
 #pragma OPENCL EXTENSION __opencl_c_program_scope_global_variables : enable
-//expected-warning@-1{{unknown OpenCL extension '__opencl_c_program_scope_global_variables' - ignoring}}
+//expected-warning@-1{{OpenCL extension '__opencl_c_program_scope_global_variables' unknown or does not require pragma - ignoring}}
 #pragma OPENCL EXTENSION __opencl_c_read_write_images : enable
-//expected-warning@-1{{unknown OpenCL extension '__opencl_c_read_write_images' - ignoring}}
+//expected-warning@-1{{OpenCL extension '__opencl_c_read_write_images' unknown or does not require pragma - ignoring}}
 #pragma OPENCL EXTENSION __opencl_c_subgroups : enable
-//expected-warning@-1{{unknown OpenCL extension '__opencl_c_subgroups' - ignoring}}
+//expected-warning@-1{{OpenCL extension '__opencl_c_subgroups' unknown or does not require pragma - ignoring}}