//===- CRunnerUtils.cpp - Utils for MLIR execution ------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements basic functions to manipulate structured MLIR types at
// runtime. Entities in this file are meant to be retargetable, including on
// targets without a C++ runtime, and must be kept C compatible.
//
//===----------------------------------------------------------------------===//

#include "mlir/ExecutionEngine/CRunnerUtils.h"

#ifndef _WIN32
#if defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__)
#include <cstdlib>
#else
#include <alloca.h>
#endif
#include <sys/time.h>
#else
#include "malloc.h"
#endif // _WIN32

#include <cinttypes>
#include <cstdio>
#include <string.h>

#ifdef MLIR_CRUNNERUTILS_DEFINE_FUNCTIONS

// Small runtime support "lib" for vector.print lowering.
// By providing elementary printing methods only, this
// library can remain fully unaware of low-level implementation
// details of our vectors. Also useful for direct LLVM IR output.
extern "C" void printI64(int64_t i) { fprintf(stdout, "%" PRId64, i); }
extern "C" void printU64(uint64_t u) { fprintf(stdout, "%" PRIu64, u); }
extern "C" void printF32(float f) { fprintf(stdout, "%g", f); }
extern "C" void printF64(double d) { fprintf(stdout, "%lg", d); }
extern "C" void printOpen() { fputs("( ", stdout); }
extern "C" void printClose() { fputs(" )", stdout); }
extern "C" void printComma() { fputs(", ", stdout); }
extern "C" void printNewline() { fputc('\n', stdout); }

extern "C" MLIR_CRUNNERUTILS_EXPORT void
memrefCopy(int64_t elemSize, UnrankedMemRefType<char> *srcArg,
           UnrankedMemRefType<char> *dstArg) {
  DynamicMemRefType<char> src(*srcArg);
  DynamicMemRefType<char> dst(*dstArg);

  int64_t rank = src.rank;
  // Handle empty shapes -> nothing to copy.
  for (int rankp = 0; rankp < rank; ++rankp)
    if (src.sizes[rankp] == 0)
      return;

  char *srcPtr = src.data + src.offset * elemSize;
  char *dstPtr = dst.data + dst.offset * elemSize;

  if (rank == 0) {
    memcpy(dstPtr, srcPtr, elemSize);
    return;
  }

  int64_t *indices = static_cast<int64_t *>(alloca(sizeof(int64_t) * rank));
  int64_t *srcStrides = static_cast<int64_t *>(alloca(sizeof(int64_t) * rank));
  int64_t *dstStrides = static_cast<int64_t *>(alloca(sizeof(int64_t) * rank));

  // Initialize index and scale strides.
  for (int rankp = 0; rankp < rank; ++rankp) {
    indices[rankp] = 0;
    srcStrides[rankp] = src.strides[rankp] * elemSize;
    dstStrides[rankp] = dst.strides[rankp] * elemSize;
  }

  int64_t readIndex = 0, writeIndex = 0;
  for (;;) {
    // Copy over the element, byte by byte.
    memcpy(dstPtr + writeIndex, srcPtr + readIndex, elemSize);
    // Advance index and read position.
    for (int64_t axis = rank - 1; axis >= 0; --axis) {
      // Advance at current axis.
      auto newIndex = ++indices[axis];
      readIndex += srcStrides[axis];
      writeIndex += dstStrides[axis];
      // If this is a valid index, we have our next index, so continue copying.
      if (src.sizes[axis] != newIndex)
        break;
      // We reached the end of this axis. If this is axis 0, we are done.
      if (axis == 0)
        return;
      // Else, reset to 0 and undo the advancement of the linear index that
      // this axis had. Then continue with the axis one outer.
      indices[axis] = 0;
      readIndex -= src.sizes[axis] * srcStrides[axis];
      writeIndex -= dst.sizes[axis] * dstStrides[axis];
    }
  }
}

/// Prints GFLOPS rating.
extern "C" void print_flops(double flops) {
  fprintf(stderr, "%lf GFLOPS\n", flops / 1.0E9);
}

/// Returns the number of seconds since Epoch 1970-01-01 00:00:00 +0000 (UTC).
extern "C" double rtclock() {
#ifndef _WIN32
  struct timeval tp;
  int stat = gettimeofday(&tp, NULL);
  if (stat != 0)
    fprintf(stderr, "Error returning time from gettimeofday: %d\n", stat);
  return (tp.tv_sec + tp.tv_usec * 1.0e-6);
#else
  fprintf(stderr, "Timing utility not implemented on Windows\n");
  return 0.0;
#endif // _WIN32
}

#endif // MLIR_CRUNNERUTILS_DEFINE_FUNCTIONS