/*
 * Copyright (c) 2011, Denis Steckelmacher <steckdenis@yahoo.fr>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the copyright holder nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/**
 * \file cpu/builtins.cpp
 * \brief Native OpenCL C built-in functions
 *
 * All these built-ins are directly called by kernels. When the LLVM JIT
 * sees a function name it doesn't know, it calls \c getBuiltin() with this
 * name as parameter. This function then returns the address of an actual
 * function implementation, that finally gets called by the kernel when
 * it is run.
 */

#include "builtins.h"
#include "kernel.h"
#include "buffer.h"

#include "../events.h"
#include "../memobject.h"

#include <sys/mman.h>
#include <signal.h>

#include <llvm/IR/Function.h>

#include <iostream>
#include <cstring>
#include <cmath>
#include <boost/math/special_functions.hpp>

#include <stdio.h>

using namespace Coal;

unsigned char *imageData(unsigned char *base, size_t x, size_t y, size_t z,
                         size_t row_pitch, size_t slice_pitch,
                         unsigned int bytes_per_pixel)
{
    unsigned char *result = base;

    result += (z * slice_pitch) +
              (y * row_pitch) +
              (x * bytes_per_pixel);

    return result;
}

/*
 * TLS-related functions
 */
__thread Coal::CPUKernelWorkGroup *g_work_group;    /*!< \brief \c Coal::CPUKernelWorkGroup currently running on this thread */
__thread void *work_items_data;                     /*!< \brief Space allocated for work-items stacks, see \ref barrier */
__thread size_t work_items_size;                    /*!< \brief Size of \c work_items_data, see \ref barrier */

void setThreadLocalWorkGroup(Coal::CPUKernelWorkGroup *current)
{
    g_work_group = current;
}

void *getWorkItemsData(size_t &size)
{
    size = work_items_size;
    return work_items_data;
}

void setWorkItemsData(void *ptr, size_t size)
{
    work_items_data = ptr;
    work_items_size = size;
}

/*
 * Actual built-ins implementations
 */
cl_uint CPUKernelWorkGroup::getWorkDim() const
{
    return p_work_dim;
}

size_t CPUKernelWorkGroup::getGlobalId(cl_uint dimindx) const
{
    if (dimindx > p_work_dim)
        return 0;

    return p_global_id_start_offset[dimindx] + p_current_context->local_id[dimindx];
}

size_t CPUKernelWorkGroup::getGlobalSize(cl_uint dimindx) const
{
    if (dimindx >p_work_dim)
        return 1;

    return p_event->global_work_size(dimindx);
}

size_t CPUKernelWorkGroup::getLocalSize(cl_uint dimindx) const
{
    if (dimindx > p_work_dim)
        return 1;

    return p_event->local_work_size(dimindx);
}

size_t CPUKernelWorkGroup::getLocalID(cl_uint dimindx) const
{
    if (dimindx > p_work_dim)
        return 0;

    return p_current_context->local_id[dimindx];
}

size_t CPUKernelWorkGroup::getNumGroups(cl_uint dimindx) const
{
    if (dimindx > p_work_dim)
        return 1;

    return (p_event->global_work_size(dimindx) /
            p_event->local_work_size(dimindx));
}

size_t CPUKernelWorkGroup::getGroupID(cl_uint dimindx) const
{
    if (dimindx > p_work_dim)
        return 0;

    return p_index[dimindx];
}

size_t CPUKernelWorkGroup::getGlobalOffset(cl_uint dimindx) const
{
    if (dimindx > p_work_dim)
        return 0;

    return p_event->global_work_offset(dimindx);
}

void CPUKernelWorkGroup::barrier(unsigned int flags)
{
    p_had_barrier = true;

    // Allocate or reuse TLS memory for the stacks (it isn't freed between
    // the work groups, and even the kernels, so if we need less space than
    // allocated, it's good)
    if (!p_contexts)
    {
        if (p_current_work_item != 0)
        {
            // Completely abnormal, it means that not every work-items
            // encounter the barrier
            std::cerr << "*** Not every work-items of "
                      << p_kernel->function()->getName().str()
                      << " calls barrier(); !" << std::endl;
            return;
        }

        // Allocate or reuse the stacks
        size_t contexts_size;
        p_contexts = getWorkItemsData(contexts_size);
        size_t needed_size = p_num_work_items * (p_stack_size + sizeof(Context));

        if (!p_contexts || contexts_size < needed_size)
        {
            // We must allocate a new space
            if (p_contexts)
                munmap(p_contexts, contexts_size);

            p_contexts = mmap(0, needed_size, PROT_EXEC | PROT_READ | PROT_WRITE, /* People say a stack must be executable */
                            MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);

            setWorkItemsData(p_contexts, contexts_size);
        }

        // Now that we have a real main context, initialize it
        p_current_context = getContextAddr(0);
        p_current_context->initialized = 1;
        std::memset(p_current_context->local_id, 0, p_work_dim * sizeof(size_t));

        getcontext(&p_current_context->context);
    }

    // Take the next context
    p_current_work_item++;
    if (p_current_work_item == p_num_work_items) p_current_work_item = 0;

    Context *next = getContextAddr(p_current_work_item);
    Context *main = getContextAddr(0);  // The context not created with makecontext

    // If the next context isn't initialized, initialize it.
    // Note: mmap zeroes the memory, so next->initialized == 0 if it isn't initialized
    if (next->initialized == 0)
    {
        next->initialized = 1;

        // local-id of next is the one of the current context, but incVec'ed
        std::memcpy(next->local_id, p_current_context->local_id,
                    MAX_WORK_DIMS * sizeof(size_t));

        incVec(p_work_dim, next->local_id, p_max_local_id);

        // Initialize the next context
        if (getcontext(&next->context) != 0)
            return;

        // Get its stack. It is located a next + sizeof(Context)
        char *stack = (char *)next;
        stack += sizeof(Context);

        next->context.uc_link = &main->context;
        next->context.uc_stack.ss_sp = stack;
        next->context.uc_stack.ss_size = p_stack_size;

        // Tell it to run the kernel function
        makecontext(&next->context, (void (*)())p_kernel_func_addr, 1, p_args);
    }

    // Switch to the next context
    ucontext_t *cur = &p_current_context->context;
    p_current_context = next;

    swapcontext(cur, &next->context);

    // When we return here, it means that all the other work items encountered
    // a barrier and that we returned to this one. We can continue.
}

void CPUKernelWorkGroup::builtinNotFound(const std::string &name) const
{
  std::cout << "OpenCL: Non-existant builtin function " << name << std::endl;
  std::cout << " found in " << p_kernel->function()->getName().str()
            << '.' << std::endl;
}

/*
 * Built-in functions
 */

static size_t get_global_id(cl_uint dimindx)
{
    return g_work_group->getGlobalId(dimindx);
}

static cl_uint get_work_dim()
{
    return g_work_group->getWorkDim();
}

static size_t get_global_size(uint dimindx)
{
    return g_work_group->getGlobalSize(dimindx);
}

static size_t get_local_size(uint dimindx)
{
    return g_work_group->getLocalSize(dimindx);
}

static size_t get_local_id(uint dimindx)
{
    return g_work_group->getLocalID(dimindx);
}

static size_t get_num_groups(uint dimindx)
{
    return g_work_group->getNumGroups(dimindx);
}

static size_t get_group_id(uint dimindx)
{
    return g_work_group->getGroupID(dimindx);
}

static size_t get_global_offset(uint dimindx)
{
    return g_work_group->getGlobalOffset(dimindx);
}

static void barrier(unsigned int flags)
{
    g_work_group->barrier(flags);
}

// Images

static int get_image_width(Image2D *image)
{
    return image->width();
}

static int get_image_height(Image2D *image)
{
    return image->height();
}

static int get_image_depth(Image3D *image)
{
    if (image->type() != MemObject::Image3D)
        return 1;

    return image->depth();
}

static int get_image_channel_data_type(Image2D *image)
{
    return image->format().image_channel_data_type;
}

static int get_image_channel_order(Image2D *image)
{
    return image->format().image_channel_order;
}

static void *image_data(Image2D *image, int x, int y, int z, int *order, int *type)
{
    *order = image->format().image_channel_order;
    *type = image->format().image_channel_data_type;

    return g_work_group->getImageData(image, x, y, z);
}

static bool is_image_3d(Image3D *image)
{
    return (image->type() == MemObject::Image3D ? 1 : 0);
}

static void write_imagef(Image2D *image, int x, int y, int z, float *color)
{
    g_work_group->writeImage(image, x, y, z, color);
}

static void write_imagei(Image2D *image, int x, int y, int z, int32_t *color)
{
    g_work_group->writeImage(image, x, y, z, color);
}

static void write_imageui(Image2D *image, int x, int y, int z, uint32_t *color)
{
    g_work_group->writeImage(image, x, y, z, color);
}

static void read_imagefi(float *result, Image2D *image, int x, int y, int z,
                         int32_t sampler)
{
    g_work_group->readImage(result, image, x, y, z, sampler);
}

static void read_imageii(int32_t *result, Image2D *image, int x, int y, int z,
                         int32_t sampler)
{
    g_work_group->readImage(result, image, x, y, z, sampler);
}

static void read_imageuii(uint32_t *result, Image2D *image, int x, int y, int z,
                         int32_t sampler)
{
    g_work_group->readImage(result, image, x, y, z, sampler);
}

static void read_imageff(float *result, Image2D *image, float x, float y,
                         float z, int32_t sampler)
{
    g_work_group->readImage(result, image, x, y, z, sampler);
}

static void read_imageif(int32_t *result, Image2D *image, float x, float y,
                         float z, int32_t sampler)
{
    g_work_group->readImage(result, image, x, y, z, sampler);
}

static void read_imageuif(uint32_t *result, Image2D *image, float x, float y,
                          float z, int32_t sampler)
{
    g_work_group->readImage(result, image, x, y, z, sampler);
}

/* Dummy function to plug missing ARM ABI EH fxns: */
static void dummy_fxn(void)
{
}


/*
 * Bridge between LLVM and us
 */
static void unimplemented_stub()
{
}

void debug_ptr(void * arg)
{
  char *s =   (char *)arg;
  float f = *(float *)arg;
  double d = *(double *)arg;
  int    i = *(int *)arg;
}

void *getBuiltin(const std::string &name)
{
    if (name == "get_global_id")
        return (void *)&get_global_id;
    else if (name == "get_work_dim")
        return (void *)&get_work_dim;
    else if (name == "get_global_size")
        return (void *)&get_global_size;
    else if (name == "get_local_size")
        return (void *)&get_local_size;
    else if (name == "get_local_id")
        return (void *)&get_local_id;
    else if (name == "get_num_groups")
        return (void *)&get_num_groups;
    else if (name == "get_group_id")
        return (void *)&get_group_id;
    else if (name == "get_global_offset")
        return (void *)&get_global_offset;
    else if (name == "barrier")
        return (void *)&barrier;

    else if (name == "__cpu_get_image_width")
        return (void *)&get_image_width;
    else if (name == "__cpu_get_image_height")
        return (void *)&get_image_height;
    else if (name == "__cpu_get_image_depth")
        return (void *)&get_image_depth;
    else if (name == "__cpu_get_image_channel_data_type")
        return (void *)&get_image_channel_data_type;
    else if (name == "__cpu_get_image_channel_order")
        return (void *)&get_image_channel_order;
    else if (name == "__cpu_image_data")
        return (void *)&image_data;
    else if (name == "__cpu_is_image_3d")
        return (void *)&is_image_3d;
    else if (name == "__cpu_write_imagef")
        return (void *)&write_imagef;
    else if (name == "__cpu_write_imagei")
        return (void *)&write_imagei;
    else if (name == "__cpu_write_imageui")
        return (void *)&write_imageui;
    else if (name == "__cpu_read_imagefi")
        return (void *)&read_imagefi;
    else if (name == "__cpu_read_imageii")
        return (void *)&read_imageii;
    else if (name == "__cpu_read_imageuii")
        return (void *)&read_imageuii;
    else if (name == "__cpu_read_imageff")
        return (void *)&read_imageff;
    else if (name == "__cpu_read_imageif")
        return (void *)&read_imageif;
    else if (name == "__cpu_read_imageuif")
        return (void *)&read_imageuif;

    // Generic hook to set debugger bpt to inspect stack variable passed as (void *)
    else if (name == "debug_ptr")
        return(void *)&debug_ptr;

    else if (name == "__aeabi_unwind_cpp_pr0")
        return (void *)&dummy_fxn;
    else if (name == "__aeabi_unwind_cpp_pr1")
        return (void *)&dummy_fxn;
    else if (name == "__aeabi_unwind_cpp_pr2")
        return (void *)&dummy_fxn;

    // Math library disambiguation for OpenCL double functions of the same name.
    else if (name == "builtin_sincos")
        return (void *)&sincos;
    else if (name == "builtin_lgamma_r")
        return (void *)&lgamma_r;
    else if (name == "builtin_modf")
        return (void *)&modf;
    else if (name == "builtin_remquo")
        return (void *)&remquo;
    else if (name == "builtin_pow")
        return (void *)&pow;
    else if (name == "builtin_exp10f")
        return (void *)&exp10f;
    else if (name == "builtin_exp10")
        return (void *)&exp10;

#if 0
    // Other misc functions Khronos tests say are builtins, though not in the spec!
    else if (name == "memcpy")
        return (void *)&memcpy;
#endif

    // Function not found
    g_work_group->builtinNotFound(name);

    return (void *)&unimplemented_stub;
}