/**************************************************************************
 *
 * Copyright 2009 VMware, Inc.
 * All Rights Reserved.
 *
 * 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, sub license, 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 (including the
 * next paragraph) 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 NON-INFRINGEMENT.
 * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS 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
 * Helpers for emiting intrinsic calls.
 *
 * LLVM vanilla IR doesn't represent all basic arithmetic operations we care
 * about, and it is often necessary to resort target-specific intrinsics for
 * performance, convenience.
 *
 * Ideally we would like to stay away from target specific intrinsics and
 * move all the instruction selection logic into upstream LLVM where it belongs.
 *
 * These functions are also used for calling C functions provided by us from
 * generated LLVM code.
 *
 * @author Jose Fonseca <jfonseca@vmware.com>
 */


#include "util/u_debug.h"
#include "util/u_string.h"
#include "util/bitscan.h"

#include "lp_bld_const.h"
#include "lp_bld_intr.h"
#include "lp_bld_type.h"
#include "lp_bld_pack.h"
#include "lp_bld_debug.h"


void
lp_format_intrinsic(char *name,
                    size_t size,
                    const char *name_root,
                    LLVMTypeRef type)
{
   unsigned length = 0;
   unsigned width;
   char c;

   LLVMTypeKind kind = LLVMGetTypeKind(type);
   if (kind == LLVMVectorTypeKind) {
      length = LLVMGetVectorSize(type);
      type = LLVMGetElementType(type);
      kind = LLVMGetTypeKind(type);
   }

   switch (kind) {
   case LLVMIntegerTypeKind:
      c = 'i';
      width = LLVMGetIntTypeWidth(type);
      break;
   case LLVMFloatTypeKind:
      c = 'f';
      width = 32;
      break;
   case LLVMDoubleTypeKind:
      c = 'f';
      width = 64;
      break;
   default:
      unreachable("unexpected LLVMTypeKind");
   }

   if (length) {
      util_snprintf(name, size, "%s.v%u%c%u", name_root, length, c, width);
   } else {
      util_snprintf(name, size, "%s.%c%u", name_root, c, width);
   }
}


LLVMValueRef
lp_declare_intrinsic(LLVMModuleRef module,
                     const char *name,
                     LLVMTypeRef ret_type,
                     LLVMTypeRef *arg_types,
                     unsigned num_args)
{
   LLVMTypeRef function_type;
   LLVMValueRef function;

   assert(!LLVMGetNamedFunction(module, name));

   function_type = LLVMFunctionType(ret_type, arg_types, num_args, 0);
   function = LLVMAddFunction(module, name, function_type);

   LLVMSetFunctionCallConv(function, LLVMCCallConv);
   LLVMSetLinkage(function, LLVMExternalLinkage);

   assert(LLVMIsDeclaration(function));

   return function;
}


#if HAVE_LLVM < 0x0400
static LLVMAttribute lp_attr_to_llvm_attr(enum lp_func_attr attr)
{
   switch (attr) {
   case LP_FUNC_ATTR_ALWAYSINLINE: return LLVMAlwaysInlineAttribute;
   case LP_FUNC_ATTR_BYVAL: return LLVMByValAttribute;
   case LP_FUNC_ATTR_INREG: return LLVMInRegAttribute;
   case LP_FUNC_ATTR_NOALIAS: return LLVMNoAliasAttribute;
   case LP_FUNC_ATTR_NOUNWIND: return LLVMNoUnwindAttribute;
   case LP_FUNC_ATTR_READNONE: return LLVMReadNoneAttribute;
   case LP_FUNC_ATTR_READONLY: return LLVMReadOnlyAttribute;
   default:
      _debug_printf("Unhandled function attribute: %x\n", attr);
      return 0;
   }
}

#else

static const char *attr_to_str(enum lp_func_attr attr)
{
   switch (attr) {
   case LP_FUNC_ATTR_ALWAYSINLINE: return "alwaysinline";
   case LP_FUNC_ATTR_BYVAL: return "byval";
   case LP_FUNC_ATTR_INREG: return "inreg";
   case LP_FUNC_ATTR_NOALIAS: return "noalias";
   case LP_FUNC_ATTR_NOUNWIND: return "nounwind";
   case LP_FUNC_ATTR_READNONE: return "readnone";
   case LP_FUNC_ATTR_READONLY: return "readonly";
   default:
      _debug_printf("Unhandled function attribute: %x\n", attr);
      return 0;
   }
}

#endif

void
lp_add_function_attr(LLVMValueRef function,
                     int attr_idx,
                     enum lp_func_attr attr)
{

#if HAVE_LLVM < 0x0400
   LLVMAttribute llvm_attr = lp_attr_to_llvm_attr(attr);
   if (attr_idx == -1) {
      LLVMAddFunctionAttr(function, llvm_attr);
   } else {
      LLVMAddAttribute(LLVMGetParam(function, attr_idx - 1), llvm_attr);
   }
#else
   LLVMContextRef context = LLVMGetModuleContext(LLVMGetGlobalParent(function));
   const char *attr_name = attr_to_str(attr);
   unsigned kind_id = LLVMGetEnumAttributeKindForName(attr_name,
                                                      strlen(attr_name));
   LLVMAttributeRef llvm_attr = LLVMCreateEnumAttribute(context, kind_id, 0);
   LLVMAddAttributeAtIndex(function, attr_idx, llvm_attr);
#endif
}

LLVMValueRef
lp_build_intrinsic(LLVMBuilderRef builder,
                   const char *name,
                   LLVMTypeRef ret_type,
                   LLVMValueRef *args,
                   unsigned num_args,
                   unsigned attr_mask)
{
   LLVMModuleRef module = LLVMGetGlobalParent(LLVMGetBasicBlockParent(LLVMGetInsertBlock(builder)));
   LLVMValueRef function;

   function = LLVMGetNamedFunction(module, name);
   if(!function) {
      LLVMTypeRef arg_types[LP_MAX_FUNC_ARGS];
      unsigned i;

      assert(num_args <= LP_MAX_FUNC_ARGS);

      for(i = 0; i < num_args; ++i) {
         assert(args[i]);
         arg_types[i] = LLVMTypeOf(args[i]);
      }

      function = lp_declare_intrinsic(module, name, ret_type, arg_types, num_args);

      /* NoUnwind indicates that the intrinsic never raises a C++ exception.
       * Set it for all intrinsics.
       */
      attr_mask |= LP_FUNC_ATTR_NOUNWIND;

      while (attr_mask) {
         enum lp_func_attr attr = 1 << u_bit_scan(&attr_mask);
         lp_add_function_attr(function, -1, attr);
      }

      if (gallivm_debug & GALLIVM_DEBUG_IR) {
         lp_debug_dump_value(function);
      }
   }

   return LLVMBuildCall(builder, function, args, num_args, "");
}


LLVMValueRef
lp_build_intrinsic_unary(LLVMBuilderRef builder,
                         const char *name,
                         LLVMTypeRef ret_type,
                         LLVMValueRef a)
{
   return lp_build_intrinsic(builder, name, ret_type, &a, 1, 0);
}


LLVMValueRef
lp_build_intrinsic_binary(LLVMBuilderRef builder,
                          const char *name,
                          LLVMTypeRef ret_type,
                          LLVMValueRef a,
                          LLVMValueRef b)
{
   LLVMValueRef args[2];

   args[0] = a;
   args[1] = b;

   return lp_build_intrinsic(builder, name, ret_type, args, 2, 0);
}


/**
 * Call intrinsic with arguments adapted to intrinsic vector length.
 *
 * Split vectors which are too large for the hw, or expand them if they
 * are too small, so a caller calling a function which might use intrinsics
 * doesn't need to do splitting/expansion on its own.
 * This only supports intrinsics where src and dst types match.
 */
LLVMValueRef
lp_build_intrinsic_binary_anylength(struct gallivm_state *gallivm,
                                    const char *name,
                                    struct lp_type src_type,
                                    unsigned intr_size,
                                    LLVMValueRef a,
                                    LLVMValueRef b)
{
   unsigned i;
   struct lp_type intrin_type = src_type;
   LLVMBuilderRef builder = gallivm->builder;
   LLVMValueRef i32undef = LLVMGetUndef(LLVMInt32TypeInContext(gallivm->context));
   LLVMValueRef anative, bnative;
   unsigned intrin_length = intr_size / src_type.width;

   intrin_type.length = intrin_length;

   if (intrin_length > src_type.length) {
      LLVMValueRef elems[LP_MAX_VECTOR_LENGTH];
      LLVMValueRef constvec, tmp;

      for (i = 0; i < src_type.length; i++) {
         elems[i] = lp_build_const_int32(gallivm, i);
      }
      for (; i < intrin_length; i++) {
         elems[i] = i32undef;
      }
      if (src_type.length == 1) {
         LLVMTypeRef elem_type = lp_build_elem_type(gallivm, intrin_type);
         a = LLVMBuildBitCast(builder, a, LLVMVectorType(elem_type, 1), "");
         b = LLVMBuildBitCast(builder, b, LLVMVectorType(elem_type, 1), "");
      }
      constvec = LLVMConstVector(elems, intrin_length);
      anative = LLVMBuildShuffleVector(builder, a, a, constvec, "");
      bnative = LLVMBuildShuffleVector(builder, b, b, constvec, "");
      tmp = lp_build_intrinsic_binary(builder, name,
                                      lp_build_vec_type(gallivm, intrin_type),
                                      anative, bnative);
      if (src_type.length > 1) {
         constvec = LLVMConstVector(elems, src_type.length);
         return LLVMBuildShuffleVector(builder, tmp, tmp, constvec, "");
      }
      else {
         return LLVMBuildExtractElement(builder, tmp, elems[0], "");
      }
   }
   else if (intrin_length < src_type.length) {
      unsigned num_vec = src_type.length / intrin_length;
      LLVMValueRef tmp[LP_MAX_VECTOR_LENGTH];

      /* don't support arbitrary size here as this is so yuck */
      if (src_type.length % intrin_length) {
         /* FIXME: This is something which should be supported
          * but there doesn't seem to be any need for it currently
          * so crash and burn.
          */
         debug_printf("%s: should handle arbitrary vector size\n",
                      __FUNCTION__);
         assert(0);
         return NULL;
      }

      for (i = 0; i < num_vec; i++) {
         anative = lp_build_extract_range(gallivm, a, i*intrin_length,
                                        intrin_length);
         bnative = lp_build_extract_range(gallivm, b, i*intrin_length,
                                        intrin_length);
         tmp[i] = lp_build_intrinsic_binary(builder, name,
                                            lp_build_vec_type(gallivm, intrin_type),
                                            anative, bnative);
      }
      return lp_build_concat(gallivm, tmp, intrin_type, num_vec);
   }
   else {
      return lp_build_intrinsic_binary(builder, name,
                                       lp_build_vec_type(gallivm, src_type),
                                       a, b);
   }
}


LLVMValueRef
lp_build_intrinsic_map(struct gallivm_state *gallivm,
                       const char *name,
                       LLVMTypeRef ret_type,
                       LLVMValueRef *args,
                       unsigned num_args)
{
   LLVMBuilderRef builder = gallivm->builder;
   LLVMTypeRef ret_elem_type = LLVMGetElementType(ret_type);
   unsigned n = LLVMGetVectorSize(ret_type);
   unsigned i, j;
   LLVMValueRef res;

   assert(num_args <= LP_MAX_FUNC_ARGS);

   res = LLVMGetUndef(ret_type);
   for(i = 0; i < n; ++i) {
      LLVMValueRef index = lp_build_const_int32(gallivm, i);
      LLVMValueRef arg_elems[LP_MAX_FUNC_ARGS];
      LLVMValueRef res_elem;
      for(j = 0; j < num_args; ++j)
         arg_elems[j] = LLVMBuildExtractElement(builder, args[j], index, "");
      res_elem = lp_build_intrinsic(builder, name, ret_elem_type, arg_elems, num_args, 0);
      res = LLVMBuildInsertElement(builder, res, res_elem, index, "");
   }

   return res;
}


LLVMValueRef
lp_build_intrinsic_map_unary(struct gallivm_state *gallivm,
                             const char *name,
                             LLVMTypeRef ret_type,
                             LLVMValueRef a)
{
   return lp_build_intrinsic_map(gallivm, name, ret_type, &a, 1);
}


LLVMValueRef
lp_build_intrinsic_map_binary(struct gallivm_state *gallivm,
                              const char *name,
                              LLVMTypeRef ret_type,
                              LLVMValueRef a,
                              LLVMValueRef b)
{
   LLVMValueRef args[2];

   args[0] = a;
   args[1] = b;

   return lp_build_intrinsic_map(gallivm, name, ret_type, args, 2);
}


