intel · bashbaug · Sep 7, 2026 · Sep 7, 2026
diff --git a/docs/install.md b/docs/install.md
@@ -16,6 +16,67 @@ OpenCL Applications or to revert back to normal operation.
 
 See the [cliloader](cliloader.md) documentation for more detail.
 
+## As an ICD Loader Layer
+
+The Intercept Layer for OpenCL Applications can be loaded by the OpenCL ICD
+loader as an ICD loader layer.
+When used as an ICD loader layer, the OpenCL ICD loader is responsible for
+loading and initializing the Intercept Layer for OpenCL applications, then
+calling it instead of calling through a dispatch table to the target ICD.
+
+To setup the Intercept Layer for OpenCL Applications as an ICD loader layer, set
+the `OPENCL_LAYERS` environment variable so it includes the Intercept Layer for
+OpenCL Applications library.
+This will usually be a full path to the library, for example:
+
+```sh
+$ export OPENCL_LAYERS="/path/to/libOpenCL.so"
+```
+
+or:
+
+```sh
+> set OPENCL_LAYERS="c:\path\to\OpenCL.dll"
+```
+
+The Intercept Layer for OpenCL Applications may also be configured as a system
+ICD loader layer.
+Please consult your OpenCL ICD loader documentation for information about
+installing and using system layers.
+
+When the Intercept Layer for OpenCL Applications is used as an ICD loader layer,
+it will first go through typical initialization when it is initially loaded:
+
+```
+-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
+CLIntercept (64-bit) is loading...
+<more loading information>
+... loading complete.
+```
+
+Then, it will go through a separate layer initialization, initiated by the
+OpenCL ICD loader:
+
+```
+CLIntercept layer is initializing...
+... layer initialization complete.
+```
+
+After the Intercept Layer for OpenCL Applications has been initialized as an ICD
+loader layer, it should operate the same as if it were installed and enabled
+through other mechanisms.
+
+For more information about ICD loader layers, please refer to the
+[cl_loader_layers](https://github.com/KhronosGroup/OpenCL-Docs/blob/main/extensions/cl_loader_layers.asciidoc)
+documentation, or follow the [OpenCL Layers Tutorial](https://github.com/Kerilk/OpenCL-Layers-Tutorial).
+
+To troubleshoot issues using the Intercept Layer for OpenCL Applications as an
+ICD loader layer, consider setting the `OCL_ICD_ENABLE_TRACE` environment
+variable (for the Khronos
+[OpenCL-ICD-Loader](https://github.com/KhronosGroup/OpenCL-ICD-Loader)) or the
+`OCL_ICD_DEBUG` environment variable (for the
+[ocl-icd](https://github.com/OCL-dev/ocl-icd) loader).
+
 ## Windows
 
 ### Local Install

diff --git a/intercept/CL/cl_function_types.h b/intercept/CL/cl_function_types.h
@@ -1191,7 +1191,7 @@ typedef cl_int CL_API_CALL clGetKernelSuggestedLocalWorkSize_t(
     cl_uint work_dim,
     const size_t* global_work_offset,
     const size_t* global_work_size,
-    size_t* suggested_local_work_size) CL_API_SUFFIX__VERSION_3_1;
+    size_t* suggested_local_work_size);
 
 typedef clGetKernelSuggestedLocalWorkSize_t *
 clGetKernelSuggestedLocalWorkSize_fn CL_API_SUFFIX__VERSION_3_1;

diff --git a/intercept/CL/cl_layer.h b/intercept/CL/cl_layer.h
@@ -0,0 +1,165 @@
+/*******************************************************************************
+ * Copyright (c) 2008-2026 The Khronos Group Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ ******************************************************************************/
+
+#ifndef OPENCL_CL_LAYER_H_
+#define OPENCL_CL_LAYER_H_
+
+/*
+** This header is generated from the Khronos OpenCL XML API Registry.
+*/
+
+// Unlike the Khronos header file, we want to unconditionally include the
+// CLIntercept cl_icd.h and cl.h, system headers.
+#include "CL/cl_icd.h"
+
+#include "CL/cl.h"
+
+/* CL_NO_PROTOTYPES implies CL_NO_EXTENSION_PROTOTYPES: */
+#if defined(CL_NO_PROTOTYPES) && !defined(CL_NO_EXTENSION_PROTOTYPES)
+#define CL_NO_EXTENSION_PROTOTYPES
+#endif
+
+/* CL_NO_EXTENSION_PROTOTYPES implies
+   CL_NO_ICD_DISPATCH_EXTENSION_PROTOTYPES and
+   CL_NO_NON_ICD_DISPATCH_EXTENSION_PROTOTYPES: */
+#if defined(CL_NO_EXTENSION_PROTOTYPES) && \
+    !defined(CL_NO_ICD_DISPATCH_EXTENSION_PROTOTYPES)
+#define CL_NO_ICD_DISPATCH_EXTENSION_PROTOTYPES
+#endif
+#if defined(CL_NO_EXTENSION_PROTOTYPES) && \
+    !defined(CL_NO_NON_ICD_DISPATCH_EXTENSION_PROTOTYPES)
+#define CL_NO_NON_ICD_DISPATCH_EXTENSION_PROTOTYPES
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/***************************************************************
+* cl_loader_layers
+***************************************************************/
+#define cl_loader_layers 1
+#define CL_LOADER_LAYERS_EXTENSION_NAME \
+    "cl_loader_layers"
+
+
+#define CL_LOADER_LAYERS_EXTENSION_VERSION CL_MAKE_VERSION(1, 0, 1)
+
+typedef cl_uint             cl_layer_info;
+typedef cl_uint             cl_layer_api_version;
+typedef cl_properties       cl_layer_properties;
+
+/* cl_layer_info */
+#define CL_LAYER_API_VERSION                                0x4240
+#define CL_LAYER_NAME                                       0x4241
+
+/* Misc API enums */
+#define CL_LAYER_API_VERSION_100                            100
+#define CL_LAYER_PROPERTIES_LIST_END                        ((cl_layer_properties)0)
+
+
+typedef cl_int CL_API_CALL
+clGetLayerInfo_t(
+    cl_layer_info param_name,
+    size_t param_value_size,
+    void* param_value,
+    size_t* param_value_size_ret);
+
+typedef clGetLayerInfo_t *
+clGetLayerInfo_fn ;
+
+typedef cl_int CL_API_CALL
+clInitLayer_t(
+    cl_uint num_entries,
+    const cl_icd_dispatch* target_dispatch,
+    cl_uint* num_entries_ret,
+    const cl_icd_dispatch** layer_dispatch_ret);
+
+typedef clInitLayer_t *
+clInitLayer_fn ;
+
+typedef cl_int CL_API_CALL
+clInitLayerWithProperties_t(
+    cl_uint num_entries,
+    const cl_icd_dispatch* target_dispatch,
+    cl_uint* num_entries_ret,
+    const cl_icd_dispatch** layer_dispatch_ret,
+    const cl_layer_properties* properties);
+
+typedef clInitLayerWithProperties_t *
+clInitLayerWithProperties_fn ;
+
+typedef cl_int CL_API_CALL
+clDeinitLayer_t(
+    void );
+
+typedef clDeinitLayer_t *
+clDeinitLayer_fn ;
+
+/*
+** The function pointer typedefs prefixed with "pfn_" are provided for
+** compatibility with earlier versions of the headers.  New code is
+** encouraged to use the function pointer typedefs that are suffixed with
+** "_fn" instead, for consistency.
+*/
+
+typedef clGetLayerInfo_t *
+pfn_clGetLayerInfo ;
+
+typedef clInitLayer_t *
+pfn_clInitLayer ;
+
+typedef clInitLayerWithProperties_t *
+pfn_clInitLayerWithProperties ;
+
+typedef clDeinitLayer_t *
+pfn_clDeinitLayer ;
+
+#if !defined(CL_NO_NON_ICD_DISPATCH_EXTENSION_PROTOTYPES)
+
+extern CL_API_ENTRY cl_int CL_API_CALL
+clGetLayerInfo(
+    cl_layer_info param_name,
+    size_t param_value_size,
+    void* param_value,
+    size_t* param_value_size_ret) ;
+
+extern CL_API_ENTRY cl_int CL_API_CALL
+clInitLayer(
+    cl_uint num_entries,
+    const cl_icd_dispatch* target_dispatch,
+    cl_uint* num_entries_ret,
+    const cl_icd_dispatch** layer_dispatch_ret) ;
+
+extern CL_API_ENTRY cl_int CL_API_CALL
+clInitLayerWithProperties(
+    cl_uint num_entries,
+    const cl_icd_dispatch* target_dispatch,
+    cl_uint* num_entries_ret,
+    const cl_icd_dispatch** layer_dispatch_ret,
+    const cl_layer_properties* properties) ;
+
+extern CL_API_ENTRY cl_int CL_API_CALL
+clDeinitLayer(
+    void ) ;
+
+#endif /* !defined(CL_NO_NON_ICD_DISPATCH_EXTENSION_PROTOTYPES) */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* OPENCL_CL_LAYER_H_ */
diff --git a/intercept/CL/cl_platform.h b/intercept/CL/cl_platform.h
@@ -243,7 +243,7 @@ typedef double                  cl_double;
 
 #define CL_NAN              (CL_INFINITY - CL_INFINITY)
 #define CL_HUGE_VALF        ((cl_float) 1e50)
-#define CL_HUGE_VAL         ((cl_double) 1e500)
+#define CL_HUGE_VAL         ((cl_double) (1e300 * 1e300))
 #define CL_MAXFLOAT         CL_FLT_MAX
 #define CL_INFINITY         CL_HUGE_VALF
 

diff --git a/intercept/CMakeLists.txt b/intercept/CMakeLists.txt
@@ -72,6 +72,7 @@ set(CLINTERCEPT_SOURCE_FILES
     src/instrumentation.h
     src/intercept.cpp
     src/intercept.h
+    src/layer.cpp
     src/main.cpp
     src/objtracker.cpp
     src/objtracker.h

diff --git a/intercept/OS/OS_linux.h b/intercept/OS/OS_linux.h
@@ -38,12 +38,7 @@
 #endif
 #endif
 
-// Since we just need the symbol clGetPlatformIDs, we can use any OpenCL
-// version.
-#if !defined(CL_TARGET_OPENCL_VERSION)
-#define CL_TARGET_OPENCL_VERSION 100
-#endif
-#include "CL/cl.h"
+void CLIntercept_Load(void);
 
 namespace OS
 {
@@ -75,7 +70,8 @@ class Services
                 const std::string& str ) const;
 
     void*   LoadLibrary(
-                const std::string& libraryName ) const;
+                const std::string& libraryName,
+                const bool deepBind = false ) const;
     void    UnloadLibrary(
                 void*& pLibrary ) const;
 
@@ -192,7 +188,8 @@ inline void Services::OutputDebugString(
 }
 
 inline void* Services::LoadLibrary(
-    const std::string& libraryName ) const
+    const std::string& libraryName,
+    const bool deepBind ) const
 {
     void* pLibrary = dlopen( libraryName.c_str(), RTLD_NOW | RTLD_GLOBAL );
     //if( pLibrary == NULL )
@@ -298,9 +295,10 @@ inline bool Services::GetCLInterceptName(
     std::string& name ) const
 {
     Dl_info info;
-    if( dladdr( (void*)clGetPlatformIDs, &info ) )
+    if( dladdr( (void*)CLIntercept_Load, &info ) )
     {
         name = info.dli_fname;
+        return true;
     }
     return false;
 }

diff --git a/intercept/OS/OS_mac.h b/intercept/OS/OS_mac.h
@@ -52,7 +52,8 @@ class Services
                 const std::string& str ) const;
 
     void*   LoadLibrary(
-                const std::string& libraryName ) const;
+                const std::string& libraryName,
+                const bool deepBind = false ) const;
     void    UnloadLibrary(
                 void*& pLibrary ) const;
 
@@ -145,9 +146,11 @@ inline void Services::OutputDebugString(
 }
 
 inline void* Services::LoadLibrary(
-    const std::string& libraryName ) const
+    const std::string& libraryName,
+    const bool deepBind ) const
 {
-    void* pLibrary = dlopen( libraryName.c_str(), RTLD_NOW );
+    const int flags = RTLD_NOW | (deepBind ? RTLD_FIRST : 0);
+    void* pLibrary = dlopen( libraryName.c_str(), flags );
     return pLibrary;
 }
 
@@ -241,6 +244,7 @@ inline bool Services::GetCLInterceptName(
     if( dladdr( (void*)CLIntercept_Load, &info ) )
     {
         name = info.dli_fname;
+        return true;
     }
     return false;
 }

diff --git a/intercept/OS/OS_windows.h b/intercept/OS/OS_windows.h
@@ -41,7 +41,8 @@ class Services
                 const std::string& str ) const;
 
     void*   LoadLibrary(
-                const std::string& libraryName ) const;
+                const std::string& libraryName,
+                bool deepBind = false ) const;
     void    UnloadLibrary(
                 void*& pLibrary ) const;
 
@@ -223,7 +224,8 @@ inline void Services::OutputDebugString(
 }
 
 inline void* Services::LoadLibrary(
-    const std::string& libraryName ) const
+    const std::string& libraryName,
+    const bool ) const
 {
     HMODULE hModule = ::LoadLibraryA( libraryName.c_str() );
     return hModule;

diff --git a/intercept/src/clIntercept.def b/intercept/src/clIntercept.def
@@ -12,6 +12,7 @@ EXPORTS
 ; ==========================================================
     clGetLayerInfo
     clInitLayer
+    clInitLayerWithProperties
 
 ; ==========================================================
 ; Standard OpenCL APIs

diff --git a/intercept/src/clIntercept.map b/intercept/src/clIntercept.map
@@ -10,6 +10,9 @@ INTERNAL {
         _binary_kernels_builtin_kernels_cl_end;
         _binary_kernels_precompiled_kernels_cl_start;
         _binary_kernels_precompiled_kernels_cl_end;
+        clGetLayerInfo;
+        clInitLayer;
+        clInitLayerWithProperties;
     local:
         *;
 };

diff --git a/intercept/src/git_version.cpp.in b/intercept/src/git_version.cpp.in
@@ -6,6 +6,6 @@
 
 #include "intercept.h"
 
-const char* CLIntercept::sc_GitDescribe = "@GIT_DESCRIBE@";
-const char* CLIntercept::sc_GitRefSpec = "@GIT_REFSPEC@";
-const char* CLIntercept::sc_GitHash = "@GIT_SHA1@";
+const char* const CLIntercept::sc_GitDescribe = "@GIT_DESCRIBE@";
+const char* const CLIntercept::sc_GitRefSpec = "@GIT_REFSPEC@";
+const char* const CLIntercept::sc_GitHash = "@GIT_SHA1@";