tdf#103395 opencl: don't initialize OpenCL when disabled

If SAL_DISABLE_OPENCL is set we don't want to do any kind of
OpenCL initialization. Put an extra guard in fillOpenCLInfo
(and similar methods in opencl package) to prevent that.

Put the check if OpenCL can be used into one place which checks
SAL_DISABLE_OPENCL and UseOpenCL in configuration.

Change-Id: Icc216d4299d3a7942843117ab9b9411de8075b11
Reviewed-on: https://gerrit.libreoffice.org/30025
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>

desktop/source/app/opencl.cxx

@@ -119,9 +119,7 @@ bool testOpenCLCompute(const Reference< XDesktop2 > &xDesktop, const OUString &r
 
 void Desktop::CheckOpenCLCompute(const Reference< XDesktop2 > &xDesktop)
 {
-    if (getenv("SAL_DISABLE_OPENCL") ||
-        Application::IsSafeModeEnabled() ||
-        !officecfg::Office::Common::Misc::UseOpenCL::get())
+    if (!opencl::canUseOpenCL() || Application::IsSafeModeEnabled())
         return;
 
     SAL_INFO("opencl", "Initiating test of OpenCL device");

include/opencl/openclwrapper.hxx

@@ -26,7 +26,8 @@
 
 #include <cstdio>
 
-namespace opencl {
+namespace opencl
+{
 
 struct KernelEnv
 {
@@ -56,6 +57,8 @@ struct OPENCL_DLLPUBLIC GPUEnv
 extern OPENCL_DLLPUBLIC GPUEnv gpuEnv;
 extern OPENCL_DLLPUBLIC sal_uInt64 kernelFailures;
 
+OPENCL_DLLPUBLIC bool canUseOpenCL();
+
 OPENCL_DLLPUBLIC bool generatBinFromKernelSource( cl_program program, const char * clFileName );
 OPENCL_DLLPUBLIC bool buildProgramFromBinary(const char* buildOption, GPUEnv* gpuEnv, const char* filename, int idx);
 OPENCL_DLLPUBLIC void setKernelEnv( KernelEnv *envInfo );

opencl/source/openclwrapper.cxx

@@ -32,6 +32,8 @@
 
 #include <cmath>
 
+#include <officecfg/Office/Common.hxx>
+
 #ifdef _WIN32
 #include <prewin.h>
 #include <postwin.h>
@@ -64,7 +66,8 @@ namespace opencl {
 GPUEnv gpuEnv;
 sal_uInt64 kernelFailures = 0;
 
-namespace {
+namespace
+{
 
 bool bIsInited = false;
 
@@ -704,7 +707,9 @@ bool createPlatformInfo(cl_platform_id nPlatformId, OpenCLPlatformInfo& rPlatfor
 const std::vector<OpenCLPlatformInfo>& fillOpenCLInfo()
 {
     static std::vector<OpenCLPlatformInfo> aPlatforms;
-    if(!aPlatforms.empty())
+
+    // return early if we already initialized or can't use OpenCL
+    if (!aPlatforms.empty() || !canUseOpenCL())
         return aPlatforms;
 
     int status = clewInit(OPENCL_DLL_NAME);
@@ -785,9 +790,16 @@ void findDeviceInfoFromDeviceId(cl_device_id aDeviceId, size_t& rDeviceId, size_
 
 }
 
+bool canUseOpenCL()
+{
+    if (getenv("SAL_DISABLE_OPENCL") || !officecfg::Office::Common::Misc::UseOpenCL::get())
+        return false;
+    return true;
+}
+
 bool switchOpenCLDevice(const OUString* pDevice, bool bAutoSelect, bool bForceEvaluation, OUString& rOutSelectedDeviceVersionIDString)
 {
-    if(fillOpenCLInfo().empty() || getenv("SAL_DISABLE_OPENCL"))
+    if (!canUseOpenCL() || fillOpenCLInfo().empty())
         return false;
 
     cl_device_id pDeviceId = nullptr;
@@ -863,6 +875,9 @@ bool switchOpenCLDevice(const OUString* pDevice, bool bAutoSelect, bool bForceEv
 
 void getOpenCLDeviceInfo(size_t& rDeviceId, size_t& rPlatformId)
 {
+    if (!canUseOpenCL())
+        return;
+
     int status = clewInit(OPENCL_DLL_NAME);
     if (status < 0)
         return;