/* MELTOPENGPU: runtime support for calls to OpenCL code generated by
   GCC MELT

  Copyright (C) 2010
  Free Software Foundation, Inc.
  Contributed by Basile Starynkevitch  <basile@starynkevitch.net>
  [funded within OpenGPU french project: http://opengpu.net/ ]

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.

GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.

You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
<http://www.gnu.org/licenses/>.  */

/***
    This runtime wraps OpenCL runtime library calls into something
    simpler. Every variable or function defined here has the
    meltopengpu_ prefix.  Variables with meltopengpu_ are read only
    from the application, unless specified otherwise.  Most of them
    are internal to this runtime, and need not to be queried at all by
    explicit user code.

    I am compiling this with
    gcc -O -Wall -fPIC -shared meltopengpu-runtime.c -lOpenCL -o libmeltopengpu.so
****/

#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <string.h>

/* this is the usual opencl header, provided by the OpenCL
   vendor... */
#include <CL/cl.h>


/* Set to one if the library has been initialized. Read-only for user application code. */
int meltopengpu_is_initialized;


/* Signature of the error routine. */
typedef void (meltopengpu_error_routine_t) (const char*);

/* The OpenCL plateform identifier, and the number of them (0 or
   1)! */
static cl_platform_id meltopengpu_platform;
static cl_uint meltopengpu_num_platforms;

/* The OpenCL GPU device. */
static cl_device_id meltopengpu_device;
static cl_uint meltopengpu_num_devices;

/* The OpenCL context. */
static cl_context meltopengpu_context;

/* The OpenCL command queue. */
static cl_command_queue meltopengpu_command_queue;

/* The pointer to the error routine. */
static meltopengpu_error_routine_t* meltopengpu_error_fun;

/* Our internal fatal error routine. */
static void meltopengpu_fatal_printf (const char*fmt, ...)
  __attribute__((format(printf,1,2)))
  __attribute__((noreturn));

static void meltopengpu_fatal_printf (const char*fmt, ...)
{
  static char errbuf[512];
  va_list args;
  memset (errbuf, 0, sizeof(errbuf));
  va_start(args, fmt);
  vsnprintf(errbuf, sizeof(errbuf)-1, fmt, args);
  va_end (args);
  if (meltopengpu_error_fun)
    meltopengpu_error_fun (errbuf);
  else {
    fputs (errbuf, stderr);
    putc('\n', stderr);
    fflush (stderr);
  }
  abort ();
}

/* This initialization code should be called by the user application,
   at the very beginning.  If the user did not call that function
   explicitly, nothing specific to MELT OPENGPU happens, and no code
   runs on the GPU. The argument is a fatal error routine function
   pointer or null; if null, any error spits a message to stderr and
   abort()-s */
void meltopengpu_initialize (meltopengpu_error_routine_t erh)
{
  cl_int got = CL_SUCCESS;
  if (erh)
    meltopengpu_error_fun = erh;

  /* Get the platform */
  got = clGetPlatformIDs(1, &meltopengpu_platform, 
			 &meltopengpu_num_platforms);
  if (got != CL_SUCCESS);
  meltopengpu_fatal_printf ("MELTOPENGPU failed to get OpenCL PlateformIDs [%d]", 
			   (int) got);

  /* Get the GPU device */
  got = clGetDeviceIDs (meltopengpu_platform,
			CL_DEVICE_TYPE_GPU, /* perhaps CL_DEVICE_TYPE_DEFAULT? */
			1,
			&meltopengpu_device,
			&meltopengpu_num_devices);
  if (got != CL_SUCCESS)
    meltopengpu_fatal_printf ("MELTOPENGPU failed to get OpenCL device [%d]",
			     (int) got); 

  /* Create the context. */
  got = CL_SUCCESS;
  meltopengpu_context
    = clCreateContext (NULL,
		       1,
		       &meltopengpu_device,
		       NULL, NULL, 
		       &got);
  if (!meltopengpu_context)
    meltopengpu_fatal_printf ("MELTOPENGPU failed to create OpenCL context [%d]",
			     (int) got);

  /* Create the command queue. */
  got = CL_SUCCESS;
  meltopengpu_command_queue
    = clCreateCommandQueue (meltopengpu_context,
			    meltopengpu_device,
			    0, 
			    &got);
  if (!meltopengpu_command_queue)
    meltopengpu_fatal_printf ("MELTOPENGPU failed to create OpenCL command queue [%d]",
			      (int) got);

  /* at last, remember that we have been initialized correctly. */
  meltopengpu_is_initialized = 1;
}

cl_program
meltopengpu_compile_program (const char*src)
{
  cl_int got = CL_SUCCESS;
  cl_program prog = NULL;
  if (!src || !meltopengpu_is_initialized)
    return NULL;
  /* compile the program */
  prog =
    clCreateProgramWithSource (meltopengpu_context,
			       1,
			       &src,
			       0,
			       &got);
  if (!prog)
    meltopengpu_fatal_printf("MELTOPENGPU failed to compile OpenCL program [%d]",
			     (int) got);
  /* build it */  
  got = clBuildProgram (prog, 1, &meltopengpu_device, NULL, NULL, NULL);
  if (got != CL_SUCCESS)
    meltopengpu_fatal_printf ("MELTOPNBPU failed to build OpenCL program [%d]",
			      (int) got);

  return prog;
}

cl_kernel 
meltopengpu_create_kernel (cl_program prog, const char*kernam)
{
  cl_kernel kern = 0;
  cl_int got = CL_SUCCESS;
  kern = clCreateKernel (prog, kernam, &got);
  if (!kern)
    meltopengpu_fatal_printf ("MELTOPNBPU failed to create kernel %s [%d]",
			      kernam, (int) got);
  return kern;
}

/* eof $Id$ */