[Mesa-dev] [PATCH 4/5 v6] clover/llvm: Add get_[cl|language]_version, validation and some helpers

[Pierre Moreau]

On 2018-03-01 — 20:02, Aaron Watry wrote:
> Used to calculate the default CLC language version based on the --cl-std in build args
> and the device capabilities.
> 
> According to section 5.8.4.5 of the 2.0 spec, the CL C version is chosen by:
>  1) If you have -cl-std=CL1.1+ use the version specified
>  2) If not, use the highest 1.x version that the device supports
> 
> Curiously, there is no valid value for -cl-std=CL1.0
> 
> Validates requested cl-std against device_clc_version
> 
> Signed-off-by: Aaron Watry <awatry at gmail.com>
> Cc: Pierre Moreau <pierre.morrow at free.fr>
> 
> v6: (Pierre) Add more const and fix some whitespace
> 
> v5: (Aaron) Use a collection of cl versions instead of switch cases
>     Consolidates the string, numeric version, and clc langstandard::kind
> 
> v4: (Pierre) Split get_language_version addition and use into separate patches
>     Squash patches that add the helpers and validate the language standard
> 
> v3: Change device_version to device_clc_version
> 
> v2: (Pierre) Move create_compiler_instance changes to correct patch
>     to prevent temporary build breakage.
>     Convert version_str into unsigned and use it to find language version
>     Add build_error for unknown language version string
>     Whitespace fixes
> ---
>  .../state_trackers/clover/llvm/invocation.cpp      | 63 ++++++++++++++++++++++
>  1 file changed, 63 insertions(+)
> 
> diff --git a/src/gallium/state_trackers/clover/llvm/invocation.cpp b/src/gallium/state_trackers/clover/llvm/invocation.cpp
> index 0bc0cccc6e..0f854b9049 100644
> --- a/src/gallium/state_trackers/clover/llvm/invocation.cpp
> +++ b/src/gallium/state_trackers/clover/llvm/invocation.cpp
> @@ -63,6 +63,23 @@ using ::llvm::Module;
>  using ::llvm::raw_string_ostream;
>  
>  namespace {
> +
> +   struct cl_version {
> +      std::string version_str; // CL Version
> +      unsigned version_number; // Numeric CL Version
> +      clang::LangStandard::Kind clc_lang_standard; // lang standard for version
> +   };
> +
> +   static const unsigned ANY_VERSION = 999;
> +   const cl_version cl_versions[] = {
> +      { "1.0", 100, clang::LangStandard::lang_opencl10},
> +      { "1.1", 110, clang::LangStandard::lang_opencl11},
> +      { "1.2", 120, clang::LangStandard::lang_opencl12},
> +      { "2.0", 200, clang::LangStandard::lang_opencl20},
> +      { "2.1", 210, clang::LangStandard::lang_unspecified}, //2.1 doesn't exist
> +      { "2.2", 220, clang::LangStandard::lang_unspecified}, //2.2 doesn't exist
> +   };

Given that OpenCL C version are no longer a 1:1 mapping to OpenCL API version,
and with the introduction of OpenCL C++ 1.0 with OpenCL 2.2, I would go with
two different tables:
* one matching strings to the integer version;
* one matching integer or string version, to the OpenCL C LangStandard
and later we can have a third one for matching integer/string to OpenCL C++
LangStandard.

> +
>     void
>     init_targets() {
>        static bool targets_initialized = false;
> @@ -93,6 +110,52 @@ namespace {
>        return ctx;
>     }
>  
> +   const struct cl_version

I think you forgot the reference there, otherwise if you want to return a copy,
you can remove the `const` keyword as it has no impact on copies.

> +   get_cl_version(const std::string &version_str,
> +                  unsigned max = ANY_VERSION) {
> +      for (const struct cl_version version : cl_versions) {

Please make `version` into a reference: no need to create a copy each time.

> +         if (version.version_number == max || version.version_str == version_str) {
> +            return version;
> +         }
> +      }
> +      throw build_error("Unknown/Unsupported language version");
> +   }
> +
> +   clang::LangStandard::Kind
> +   get_lang_standard_from_version_str(const std::string &version_str,
> +                                      bool is_build_opt = false) {
> +       /**
> +       * Per CL 2.0 spec, section 5.8.4.5:
> +       * If it's an option, use the value directly.
> +       * If it's a device version, clamp to max 1.x version, a.k.a. 1.2
> +       */

Please switch to regular C++-style comments.

> +      const struct cl_version version = get_cl_version(version_str,
> +                                      is_build_opt ? ANY_VERSION : 120);
> +      return version.clc_lang_standard;
> +   }
> +
> +   clang::LangStandard::Kind
> +   get_language_version(const std::vector<std::string> &opts,
> +                        const std::string &device_version) {
> +
> +      const std::string search = "-cl-std=CL";
> +
> +      for (auto opt: opts) {

opt could be a constant reference, to avoid making copies of strings every
time.

With those modifications, this is
Reviewed-by: Pierre Moreau <pierre.morrow at free.fr>

> +         auto pos = opt.find(search);
> +         if (pos == 0){
> +            const auto ver = opt.substr(pos + search.size());
> +            const auto device_ver = get_cl_version(device_version);
> +            const auto requested = get_cl_version(ver);
> +            if (requested.version_number > device_ver.version_number) {
> +               throw build_error();
> +            }
> +            return get_lang_standard_from_version_str(ver, true);
> +         }
> +      }
> +
> +      return get_lang_standard_from_version_str(device_version);
> +   }
> +
>     std::unique_ptr<clang::CompilerInstance>
>     create_compiler_instance(const device &dev,
>                              const std::vector<std::string> &opts,
> -- 
> 2.14.1
> 
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