fosphor/cl: Handle CL 1.1 vs 1.2 differently

The OpenCL 1.2 is nicer but we can't always use it and on linux,
even if the CL_VERSION_1_2 exists, we can't trust it because distrib
sometimes have CL 1.2 headers with a CL 1.1 dispatcher.

So instead, we only assume we have 1.1 header and lib at compile time.
Then at run-time we do a dynamic lookup of the 1.2 symbols from the lib.
We also check if the actual selected platform does support 1.2 (you
could have a 1.2 dispatcher with a 1.1 platform implementation).

If both conditions are satisfied, then we dispatch the call to the 1.2
implementation and if not, then we dispatch them to a local fallback
implementation of the functions (but limited to the functions we need)

It's not pretty but it should work and it isolates all the hack magic
inside cl_compat.{c,h} and you just use the CL1.2 API normally outside
of it.

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>

5 files changed, 225 insertions, 12 deletions

diff --git a/lib/fosphor/Makefile b/lib/fosphor/Makefile
index 9007af3..a8fb3bb 100644
--- a/lib/fosphor/Makefile
+++ b/lib/fosphor/Makefile
@@ -6,7 +6,7 @@ ifneq ($(AMDAPPSDKROOT), )
 CFLAGS+=-I$(AMDAPPSDKROOT)/include
 endif
 ifeq ($(UNAME), Linux)
-LDLIBS+=-lOpenCL -lGL
+LDLIBS+=-lOpenCL -lGL -ldl
 endif
 ifeq ($(UNAME), Darwin)
 LDLIBS+=-framework OpenCL -framework OpenGL -framework Cocoa -framework IOKit
@@ -20,7 +20,7 @@ all: main
 resource_data.c: $(RESOURCE_FILES) mkresources.py
 	./mkresources.py $(RESOURCE_FILES) > resource_data.c
 
-main: resource.o resource_data.o axis.o cl.o fosphor.o gl.o gl_cmap.o gl_cmap_gen.o gl_font.o main.o
+main: resource.o resource_data.o axis.o cl.o cl_compat.o fosphor.o gl.o gl_cmap.o gl_cmap_gen.o gl_font.o main.o
 
 clean:
 	rm -f main *.o resource_data.c
diff --git a/lib/fosphor/cl.c b/lib/fosphor/cl.c
index 7cbb795..edf82c3 100644
--- a/lib/fosphor/cl.c
+++ b/lib/fosphor/cl.c
@@ -34,6 +34,7 @@
 #include <string.h>
 
 #include "cl_platform.h"
+#include "cl_compat.h"
 
 #if defined(__APPLE__) || defined(MAXOSX)
 # include <OpenGL/OpenGL.h>
@@ -461,7 +462,7 @@ cl_do_init(struct fosphor *self)
 
 	/* GL shared objects */
 		/* Waterfall texture */
-	cl->mem_waterfall = clCreateFromGLTexture2D(cl->ctx,
+	cl->mem_waterfall = clCreateFromGLTexture(cl->ctx,
 		CL_MEM_READ_WRITE, GL_TEXTURE_2D, 0,
 		fosphor_gl_get_shared_id(self, GL_ID_TEX_WATERFALL),
 		&err
@@ -469,7 +470,7 @@ cl_do_init(struct fosphor *self)
 	CL_ERR_CHECK(err, "Unable to share waterfall texture into OpenCL context");
 
 		/* Histogram texture */
-	cl->mem_histogram = clCreateFromGLTexture2D(cl->ctx,
+	cl->mem_histogram = clCreateFromGLTexture(cl->ctx,
 		CL_MEM_READ_WRITE, GL_TEXTURE_2D, 0,
 		fosphor_gl_get_shared_id(self, GL_ID_TEX_HISTOGRAM),
 		&err
@@ -600,6 +601,10 @@ fosphor_cl_init(struct fosphor *self)
 
 	fprintf(stderr, "[+] Selected device: %s\n", dev_name);
 
+	/* Setup compatibility layer for this platform */
+	cl_compat_init();
+	cl_compat_check_platform(cl->pl_id);
+
 	/* Initialize selected platform / device */
 	err = cl_do_init(self);
 	if (err)
diff --git a/lib/fosphor/cl_compat.c b/lib/fosphor/cl_compat.c
new file mode 100644
index 0000000..f735a97
--- /dev/null
+++ b/lib/fosphor/cl_compat.c
@@ -0,0 +1,150 @@
+/*
+ * cl_compat.c
+ *
+ * Handle OpenCL 1.1 <> 1.2 fallback and the related uglyness
+ *
+ * Copyright (C) 2013-2014 Sylvain Munaut
+ *
+ * This program 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 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*! \addtogroup cl
+ * @{
+ */
+
+/*! \file cl_compat.c
+ *  \brief Handle OpenCL 1.1 <> 1.2 fallback and the related uglyness
+ */
+
+/* Include whatever is needed for dynamic symbol lookup */
+#ifdef _WIN32
+# include <Windows.h>
+#else
+# define _GNU_SOURCE
+# include <dlfcn.h>
+#endif
+
+#include <stdio.h>
+#include <string.h>
+
+/* Make sure we allow OpenCL 1.1 fn without warnings */
+#define CL_USE_DEPRECATED_OPENCL_1_1_APIS
+
+#include "cl_compat.h"
+
+
+/* -------------------------------------------------------------------------- */
+/* Fallback magic                                                             */
+/* -------------------------------------------------------------------------- */
+
+#define ALT_WRAP(rtype, fn, arg_list, arg_call)		\
+							\
+	static CL_API_ENTRY rtype CL_API_CALL (* fn ## _icd) arg_list = NULL; \
+	static rtype fn ## _alt arg_list;		\
+							\
+	CL_API_ENTRY rtype CL_API_CALL fn arg_list	\
+	{						\
+		if (g_allow_cl12 && fn ## _icd)		\
+			return fn ## _icd arg_call;	\
+		else					\
+			return fn ## _alt arg_call;	\
+	}						\
+							\
+	static rtype fn ## _alt arg_list
+
+#define ALT_INIT(fn)					\
+	*(void **)(&fn ## _icd) = _cl_icd_get_sym(#fn);	\
+	if (!fn ## _icd)				\
+		g_allow_cl12 = 0;
+
+
+/*! \brief Whether to allow direct CL 1.2 usage or not */
+static int g_allow_cl12 = 1;
+
+
+/*! \brief Tries to find a function pointer to a given OpenCL function
+ *  \param[in] fn The name of the function to lookup
+ */
+static void *
+_cl_icd_get_sym(const char *fn)
+{
+#ifdef _WIN32
+	static HMODULE h = NULL;
+	if (!h)
+		h = GetModuleHandle(L"OpenCL.dll");
+	return GetProcAddress(h, fn);
+#else
+	return dlsym(RTLD_NEXT, fn);
+#endif
+}
+
+
+/* -------------------------------------------------------------------------- */
+/* Fallback implementations                                                   */
+/* -------------------------------------------------------------------------- */
+/* These are only valid for fosphor and might not cover all use cases ! */
+
+ALT_WRAP(cl_mem,
+         clCreateFromGLTexture,
+             (cl_context context,
+              cl_mem_flags flags,
+              GLenum texture_target,
+              GLint miplevel,
+              GLuint texture,
+              cl_int *errcode_ret),
+             (context, flags, texture_target, miplevel, texture, errcode_ret)
+)
+{
+	return clCreateFromGLTexture2D(
+		context,
+		flags,
+		texture_target,
+		miplevel,
+		texture,
+		errcode_ret
+	);
+}
+
+
+/* -------------------------------------------------------------------------- */
+/* Compat API control                                                         */
+/* -------------------------------------------------------------------------- */
+
+void
+cl_compat_init(void)
+{
+	ALT_INIT(clCreateFromGLTexture)
+}
+
+void
+cl_compat_check_platform(cl_platform_id pl_id)
+{
+	cl_int err;
+	char buf[128];
+
+	if (!g_allow_cl12)
+		return;
+
+	err = clGetPlatformInfo(pl_id, CL_PLATFORM_VERSION, sizeof(buf), buf, NULL);
+	if (err != CL_SUCCESS) {
+		fprintf(stderr, "[!] Failed to fetch platform version. Assume it can't do OpenCL 1.2\n");
+		g_allow_cl12 = 0;
+	}
+
+	if (strncmp(buf, "OpenCL 1.2 ", 11)) {
+		g_allow_cl12 = 0;
+	}
+}
+
+/*! @} */
diff --git a/lib/fosphor/cl_compat.h b/lib/fosphor/cl_compat.h
new file mode 100644
index 0000000..a1c5b33
--- /dev/null
+++ b/lib/fosphor/cl_compat.h
@@ -0,0 +1,65 @@
+/*
+ * cl_compat.h
+ *
+ * Handle OpenCL 1.1 <> 1.2 fallback and the related uglyness
+ *
+ * Copyright (C) 2013-2014 Sylvain Munaut
+ *
+ * This program 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 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __FOSPHOR_CL_COMPAT_H__
+#define __FOSPHOR_CL_COMPAT_H__
+
+/*! \ingroup cl
+ * @{
+ */
+
+/*! \file cl_compat.h
+ *  \brief Handle OpenCL 1.1 <> 1.2 fallback and the related uglyness
+ */
+
+#include "cl_platform.h"
+#include "gl_platform.h"
+
+
+/* Define NVidia specific attributes */
+#ifndef CL_DEVICE_COMPUTE_CAPABILITY_MAJOR_NV
+# define CL_DEVICE_COMPUTE_CAPABILITY_MAJOR_NV	0x4000
+# define CL_DEVICE_COMPUTE_CAPABILITY_MINOR_NV	0x4001
+#endif
+
+
+/* If OpenCL 1.2 isn't supported in the header, add our prototypes */
+#ifndef CL_VERSION_1_2
+
+cl_mem
+clCreateFromGLTexture(cl_context context,
+                      cl_mem_flags flags,
+                      GLenum texture_target,
+                      GLint miplevel,
+                      GLuint texture,
+                      cl_int *errcode_ret);
+
+#endif
+
+
+/* The actual API */
+void cl_compat_init(void);
+void cl_compat_check_platform(cl_platform_id pl_id);
+
+
+/*! @} */
+
+#endif /* __FOSPHOR_CL_COMPAT_H__ */
diff --git a/lib/fosphor/cl_platform.h b/lib/fosphor/cl_platform.h
index 38ba8ab..2816726 100644
--- a/lib/fosphor/cl_platform.h
+++ b/lib/fosphor/cl_platform.h
@@ -27,22 +27,15 @@
 # define _WIN32
 #endif
 
+
 #if defined(__APPLE__) || defined(MAXOSX)
 # include <OpenCL/cl.h>
 # include <OpenCL/cl_ext.h>
 # include <OpenCL/cl_gl.h>
 # include <OpenCL/cl_gl_ext.h>
-# ifdef CL_VERSION_1_2
-#  define clCreateFromGLTexture2D clCreateFromGLTexture
-# endif
 #else
 # define CL_USE_DEPRECATED_OPENCL_1_1_APIS
 # include <CL/cl.h>
 # include <CL/cl_ext.h>
 # include <CL/cl_gl.h>
 #endif
-
-#ifndef CL_DEVICE_COMPUTE_CAPABILITY_MAJOR_NV
-# define CL_DEVICE_COMPUTE_CAPABILITY_MAJOR_NV	0x4000
-# define CL_DEVICE_COMPUTE_CAPABILITY_MINOR_NV	0x4001
-#endif