From 3efdfb3979c429f3f0c8e2e7a47672de8deceac6 Mon Sep 17 00:00:00 2001
From: ohadagoogle <ohada@google.com>
Date: Mon, 20 Jun 2022 16:16:13 +0000
Subject: Enable loading OpenCL symbols in Android App native code, NDK
 environment.

 * Based on ArmNN work: IVGCVSW-6960
   Device not found running MLTS with Support Library

Change-Id: I8cb8acc30c8a4afa60bc1cf80eb5b6b2c43dfdc1
Signed-off-by: Ohad Almagor <ohada@google.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/7836
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Gian Marco Iodice <gianmarco.iodice@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Benchmark: Arm Jenkins <bsgcomp@arm.com>
---
 arm_compute/core/CL/OpenCL.h |  5 +++--
 src/core/CL/OpenCL.cpp       | 40 +++++++++++++++++++++++++++++++++++++---
 2 files changed, 40 insertions(+), 5 deletions(-)

diff --git a/arm_compute/core/CL/OpenCL.h b/arm_compute/core/CL/OpenCL.h
index 93f7c318dd..058214bd07 100644
--- a/arm_compute/core/CL/OpenCL.h
+++ b/arm_compute/core/CL/OpenCL.h
@@ -75,11 +75,12 @@ public:
     static CLSymbols &get();
     /** Load symbols from the given OpenCL library path.
      *
-     * @param[in] library Path to the OpenCL library.
+     * @param[in] library    Path to the OpenCL library.
+     * @param[in] use_loader Use symbol loader function loadOpenCLPointer.
      *
      * @return True if loading the library is successful.
      */
-    bool load(const std::string &library);
+    bool load(const std::string &library, bool use_loader = false);
     /** Load symbols from any of the default OpenCL library names.
      *
      * @return True if loading any library is successful.
diff --git a/src/core/CL/OpenCL.cpp b/src/core/CL/OpenCL.cpp
index d5034ba8fa..b391950e1b 100644
--- a/src/core/CL/OpenCL.cpp
+++ b/src/core/CL/OpenCL.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2021 Arm Limited.
+ * Copyright (c) 2017-2022 Arm Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -62,18 +62,32 @@ bool CLSymbols::load_default()
 
     for(const auto &lib : libraries)
     {
-        if(load(lib))
+        if(load(lib, /* use_loader */false))
         {
             ARM_COMPUTE_ERROR_ON_MSG(this->clBuildProgram_ptr == nullptr, "Failed to load OpenCL symbols from shared library");
             return true;
         }
     }
 
+#ifdef __ANDROID__
+    // When running in NDK environment, the above libraries are not accessible.
+    static const std::vector<std::string> android_libraries{ "libOpenCL-pixel.so", "libOpenCL-car.so" };
+
+    for(const auto &lib : android_libraries)
+    {
+        if(load(lib, /* use_loader */true))
+        {
+            ARM_COMPUTE_ERROR_ON_MSG(this->clBuildProgram_ptr == nullptr, "Failed to load OpenCL symbols from android shared library");
+            return true;
+        }
+    }
+#endif /* __ANDROID__ */
+
     std::cerr << "Couldn't find any OpenCL library.\n";
     return false;
 }
 
-bool CLSymbols::load(const std::string &library)
+bool CLSymbols::load(const std::string &library, bool use_loader)
 {
     void *handle = dlopen(library.c_str(), RTLD_LAZY | RTLD_LOCAL);
 
@@ -85,8 +99,28 @@ bool CLSymbols::load(const std::string &library)
         return false;
     }
 
+#ifdef __ANDROID__
+    typedef void* (*loadOpenCLPointer_t)(const char* name);
+    loadOpenCLPointer_t loadOpenCLPointer;
+    if (use_loader) {
+        typedef void (*enableOpenCL_t)();
+        enableOpenCL_t enableOpenCL =
+            reinterpret_cast<enableOpenCL_t>(dlsym(handle, "enableOpenCL"));
+        enableOpenCL();
+
+        loadOpenCLPointer = reinterpret_cast<loadOpenCLPointer_t>(
+            dlsym(handle, "loadOpenCLPointer"));
+    } else {
+        loadOpenCLPointer = nullptr;
+    }
+#define LOAD_FUNCTION_PTR(func_name, _handle) \
+    func_name##_ptr = reinterpret_cast<decltype(func_name) *>( use_loader ? \
+        loadOpenCLPointer(#func_name) : dlsym(handle, #func_name));
+#else /* __ANDROID__ */
+    (void)use_loader; // Avoid unused warning
 #define LOAD_FUNCTION_PTR(func_name, handle) \
     func_name##_ptr = reinterpret_cast<decltype(func_name) *>(dlsym(handle, #func_name));
+#endif /* __ANDROID__ */
 
     LOAD_FUNCTION_PTR(clCreateContext, handle);
     LOAD_FUNCTION_PTR(clCreateContextFromType, handle);
-- 
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