clc: Allow bitfields

bitfields are not officially supported by Open CL but there is a clang
extension that adds support.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33576>

src/compiler/clc/clc.h

@@ -92,6 +92,11 @@ struct clc_compile_args {
     */
    const char * const *allowed_spirv_extensions;
 
+   /* Indicate that the input file tries to be compatible with C code. This
+    * means that for example the bit-field clang extension is enabled.
+    */
+   bool c_compatible;
+
    unsigned address_bits;
 };
 

src/compiler/clc/clc_helpers.cpp

@@ -945,6 +945,9 @@ clc_compile_to_llvm_module(LLVMContext &llvm_ctx,
    c->getTargetOpts().OpenCLExtensionsAsWritten.push_back("+cl_khr_global_int32_extended_atomics");
    c->getTargetOpts().OpenCLExtensionsAsWritten.push_back("+cl_khr_local_int32_base_atomics");
    c->getTargetOpts().OpenCLExtensionsAsWritten.push_back("+cl_khr_local_int32_extended_atomics");
+   if (args->c_compatible) {
+      c->getTargetOpts().OpenCLExtensionsAsWritten.push_back("+__cl_clang_bitfields");
+   }
    c->getPreprocessorOpts().addMacroDef("cl_khr_expect_assume=1");
 
    bool needs_opencl_c_h = false;

src/compiler/clc/mesa_clc.c

@@ -133,6 +133,7 @@ main(int argc, char **argv)
          .source.value = map,
          .args = util_dynarray_begin(&clang_args),
          .num_args = util_dynarray_num_elements(&clang_args, char *),
+         .c_compatible = true,
       };
 
       /* Enable all features, we don't know the target here and it is the

src/gallium/frontends/rusticl/mesa/compiler/clc/spirv.rs

@@ -151,6 +151,7 @@ impl SPIRVBin {
             features: features,
             use_llvm_spirv_target: false,
             allowed_spirv_extensions: spirv_extensions.as_ptr(),
+            c_compatible: false,
             address_bits: address_bits,
         };
         let mut msgs: Vec<String> = Vec::new();