//
// Copyright 2012-2016 Francisco Jerez
// Copyright 2012-2016 Advanced Micro Devices, Inc.
// Copyright 2015 Zoltan Gilian
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
// OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
// OTHER DEALINGS IN THE SOFTWARE.
//

///
/// \file
/// Codegen back-end-independent part of the construction of an executable
/// clover::binary, including kernel argument metadata extraction and
/// formatting of the pre-generated binary code in a form that can be
/// understood by pipe drivers.
///

#include <llvm/Support/Allocator.h>

#include "llvm/codegen.hpp"
#include "llvm/metadata.hpp"

#include "CL/cl.h"

#include "pipe/p_state.h"
#include "util/u_math.h"

#include <clang/Basic/TargetInfo.h>

using clover::binary;
using clover::detokenize;
using namespace clover::llvm;

using ::llvm::Module;
using ::llvm::Function;
using ::llvm::Type;
using ::llvm::isa;
using ::llvm::cast;
using ::llvm::dyn_cast;

namespace {
   enum binary::argument::type
   get_image_type(const std::string &type,
                  const std::string &qual) {
      if (type == "image1d_t" || type == "image2d_t" || type == "image3d_t") {
         if (qual == "read_only")
            return binary::argument::image_rd;
         else if (qual == "write_only")
            return binary::argument::image_wr;
      }

      unreachable("Unsupported image type");
   }

   binary::arg_info create_arg_info(const std::string &arg_name,
                                    const std::string &type_name,
                                    const std::string &type_qualifier,
                                    const uint64_t address_qualifier,
                                    const std::string &access_qualifier) {

      cl_kernel_arg_type_qualifier cl_type_qualifier =
                                                   CL_KERNEL_ARG_TYPE_NONE;
      if (type_qualifier.find("const") != std::string::npos)
         cl_type_qualifier |= CL_KERNEL_ARG_TYPE_CONST;
      if (type_qualifier.find("restrict") != std::string::npos)
         cl_type_qualifier |=  CL_KERNEL_ARG_TYPE_RESTRICT;
      if (type_qualifier.find("volatile") != std::string::npos)
         cl_type_qualifier |=  CL_KERNEL_ARG_TYPE_VOLATILE;

      cl_kernel_arg_address_qualifier cl_address_qualifier =
                                             CL_KERNEL_ARG_ADDRESS_PRIVATE;
      if (address_qualifier == 1)
         cl_address_qualifier = CL_KERNEL_ARG_ADDRESS_GLOBAL;
      else if (address_qualifier == 2)
         cl_address_qualifier =  CL_KERNEL_ARG_ADDRESS_CONSTANT;
      else if (address_qualifier == 3)
         cl_address_qualifier =  CL_KERNEL_ARG_ADDRESS_LOCAL;

      cl_kernel_arg_access_qualifier cl_access_qualifier =
                                                   CL_KERNEL_ARG_ACCESS_NONE;
      if (access_qualifier == "read_only")
         cl_access_qualifier = CL_KERNEL_ARG_ACCESS_READ_ONLY;
      else if (access_qualifier == "write_only")
         cl_access_qualifier = CL_KERNEL_ARG_ACCESS_WRITE_ONLY;
      else if (access_qualifier == "read_write")
         cl_access_qualifier = CL_KERNEL_ARG_ACCESS_READ_WRITE;

      return binary::arg_info(arg_name, type_name, cl_type_qualifier,
                              cl_address_qualifier, cl_access_qualifier);
   }

   std::vector<size_t>
   get_reqd_work_group_size(const Module &mod,
                            const std::string &kernel_name) {
      const Function &f = *mod.getFunction(kernel_name);
      auto vector_metadata = get_uint_vector_kernel_metadata(f, "reqd_work_group_size");

      return vector_metadata.empty() ? std::vector<size_t>({0, 0, 0}) : vector_metadata;
   }


   std::string
   kernel_attributes(const Module &mod, const std::string &kernel_name) {
      std::vector<std::string> attributes;

      const Function &f = *mod.getFunction(kernel_name);

      auto vec_type_hint = get_type_kernel_metadata(f, "vec_type_hint");
      if (!vec_type_hint.empty())
         attributes.emplace_back("vec_type_hint(" + vec_type_hint + ")");

      auto work_group_size_hint = get_uint_vector_kernel_metadata(f, "work_group_size_hint");
      if (!work_group_size_hint.empty()) {
         std::string s = "work_group_size_hint(";
         s += detokenize(work_group_size_hint, ",");
         s += ")";
         attributes.emplace_back(s);
      }

      auto reqd_work_group_size = get_uint_vector_kernel_metadata(f, "reqd_work_group_size");
      if (!reqd_work_group_size.empty()) {
         std::string s = "reqd_work_group_size(";
         s += detokenize(reqd_work_group_size, ",");
         s += ")";
         attributes.emplace_back(s);
      }

      auto nosvm = get_str_kernel_metadata(f, "nosvm");
      if (!nosvm.empty())
         attributes.emplace_back("nosvm");

      return detokenize(attributes, " ");
   }

   std::vector<binary::argument>
   make_kernel_args(const Module &mod, const std::string &kernel_name,
                    const clang::CompilerInstance &c) {
      std::vector<binary::argument> args;
      const Function &f = *mod.getFunction(kernel_name);
      ::llvm::DataLayout dl(&mod);
      const auto size_type =
         dl.getSmallestLegalIntType(mod.getContext(), sizeof(cl_uint) * 8);

      for (const auto &arg : f.args()) {
         const auto arg_type = arg.getType();

         // OpenCL 1.2 specification, Ch. 6.1.5: "A built-in data
         // type that is not a power of two bytes in size must be
         // aligned to the next larger power of two.
         // This rule applies to built-in types only, not structs or unions."
         const unsigned arg_api_size = dl.getTypeAllocSize(arg_type);

         const unsigned target_size = dl.getTypeStoreSize(arg_type);
         const unsigned target_align = dl.getABITypeAlignment(arg_type);

         const auto type_name = get_str_argument_metadata(f, arg,
                                                          "kernel_arg_type");
         if (type_name == "image2d_t" || type_name == "image3d_t") {
            // Image.
            const auto access_qual = get_str_argument_metadata(
               f, arg, "kernel_arg_access_qual");
            args.emplace_back(get_image_type(type_name, access_qual),
                              target_size, target_size,
                              target_align, binary::argument::zero_ext);

         } else if (type_name == "sampler_t") {
            args.emplace_back(binary::argument::sampler, arg_api_size,
                              target_size, target_align,
                              binary::argument::zero_ext);

         } else if (type_name == "__llvm_image_size") {
            // Image size implicit argument.
            args.emplace_back(binary::argument::scalar, sizeof(cl_uint),
                              dl.getTypeStoreSize(size_type),
                              dl.getABITypeAlignment(size_type),
                              binary::argument::zero_ext,
                              binary::argument::image_size);

         } else if (type_name == "__llvm_image_format") {
            // Image format implicit argument.
            args.emplace_back(binary::argument::scalar, sizeof(cl_uint),
                              dl.getTypeStoreSize(size_type),
                              dl.getABITypeAlignment(size_type),
                              binary::argument::zero_ext,
                              binary::argument::image_format);

         } else {
            // Other types.
            const auto actual_type =
               isa< ::llvm::PointerType>(arg_type) && arg.hasByValAttr() ?
               cast< ::llvm::PointerType>(arg_type)->getElementType() : arg_type;

            if (actual_type->isPointerTy()) {
               const unsigned address_space =
                  cast< ::llvm::PointerType>(actual_type)->getAddressSpace();

               const auto &map = c.getTarget().getAddressSpaceMap();
               const auto offset =
                           static_cast<unsigned>(clang::LangAS::opencl_local);
               if (address_space == map[offset]) {
                  const auto pointee_type = cast<
                     ::llvm::PointerType>(actual_type)->getElementType();
                  args.emplace_back(binary::argument::local, arg_api_size,
                                    target_size,
                                    dl.getABITypeAlignment(pointee_type),
                                    binary::argument::zero_ext);
               } else {
                  // XXX: Correctly handle constant address space.  There is no
                  // way for r600g to pass a handle for constant buffers back
                  // to clover like it can for global buffers, so
                  // creating constant arguments will break r600g.  For now,
                  // continue treating constant buffers as global buffers
                  // until we can come up with a way to create handles for
                  // constant buffers.
                  args.emplace_back(binary::argument::global, arg_api_size,
                                    target_size, target_align,
                                    binary::argument::zero_ext);
               }

            } else {
               const bool needs_sign_ext = f.getAttributes().hasParamAttr(
                  arg.getArgNo(), ::llvm::Attribute::SExt);

               args.emplace_back(binary::argument::scalar, arg_api_size,
                                 target_size, target_align,
                                 (needs_sign_ext ? binary::argument::sign_ext :
                                  binary::argument::zero_ext));
            }

            // Add kernel argument infos if built with -cl-kernel-arg-info.
            if (c.getCodeGenOpts().EmitOpenCLArgMetadata) {
               args.back().info = create_arg_info(
                  get_str_argument_metadata(f, arg, "kernel_arg_name"),
                  type_name,
                  get_str_argument_metadata(f, arg, "kernel_arg_type_qual"),
                  get_uint_argument_metadata(f, arg, "kernel_arg_addr_space"),
                  get_str_argument_metadata(f, arg, "kernel_arg_access_qual"));
            }
         }
      }

      // Append implicit arguments.  XXX - The types, ordering and
      // vector size of the implicit arguments should depend on the
      // target according to the selected calling convention.
      args.emplace_back(binary::argument::scalar, sizeof(cl_uint),
                        dl.getTypeStoreSize(size_type),
                        dl.getABITypeAlignment(size_type),
                        binary::argument::zero_ext,
                        binary::argument::grid_dimension);

      args.emplace_back(binary::argument::scalar, sizeof(cl_uint),
                        dl.getTypeStoreSize(size_type),
                        dl.getABITypeAlignment(size_type),
                        binary::argument::zero_ext,
                        binary::argument::grid_offset);

      return args;
   }

   binary::section
   make_text_section(const std::vector<char> &code) {
      const pipe_binary_program_header header { uint32_t(code.size()) };
      binary::section text { 0, binary::section::text_executable,
                             header.num_bytes, {} };

      text.data.insert(text.data.end(), reinterpret_cast<const char *>(&header),
                       reinterpret_cast<const char *>(&header) + sizeof(header));
      text.data.insert(text.data.end(), code.begin(), code.end());

      return text;
   }
}

binary
clover::llvm::build_module_common(const Module &mod,
                                  const std::vector<char> &code,
                                  const std::map<std::string,
                                                 unsigned> &offsets,
                                  const clang::CompilerInstance &c) {
   binary b;

   for (const auto &llvm_name : map(std::mem_fn(&Function::getName),
                               get_kernels(mod))) {
      const ::std::string name(llvm_name);
      if (offsets.count(name))
         b.syms.emplace_back(name, kernel_attributes(mod, name),
                             get_reqd_work_group_size(mod, name),
                             0, offsets.at(name),
                             make_kernel_args(mod, name, c));
   }

   b.secs.push_back(make_text_section(code));
   return b;
}
