Fixes nvcc terminals popping up during CUDA JIT compilation due to invoking...

Fixes nvcc terminals popping up during CUDA JIT compilation due to invoking system("nvcc ..."). Replaced with MSVC's native CreateProcess() function. 

platforms/cuda/src/CudaContext.cpp

@@ -309,6 +309,29 @@ CUmodule CudaContext::createModule(const string source, const char* optimization
     return createModule(source, map<string, string>(), optimizationFlags);
 }
 
+#ifdef WIN32
+#include <Windows.h>
+static bool compileInWindows(const string &command) {
+    // COMSPEC is an env variable pointing to full dir of cmd.exe
+    // it always defined on pretty much all Windows OSes
+    string fullcommand = getenv("COMSPEC") + string(" /C ") + command;
+    STARTUPINFO si;
+    PROCESS_INFORMATION pi;
+    ZeroMemory( &si, sizeof(si) );
+    si.cb = sizeof(si);
+    ZeroMemory( &pi, sizeof(pi) );
+    vector<char> args(std::max(1000, (int) fullcommand.size()+1));
+    strcpy(&args[0], fullcommand.c_str());
+    si.dwFlags = STARTF_USESHOWWINDOW;
+    si.wShowWindow = SW_HIDE;
+    if (!CreateProcess(NULL, &args[0], NULL, NULL, FALSE, 0, NULL, NULL, &si, &pi)) {
+        return -1;
+    }
+    WaitForSingleObject(pi.hProcess, INFINITE);
+    return 0;
+}
+#endif
+
 CUmodule CudaContext::createModule(const string source, const map<string, string>& defines, const char* optimizationFlags) {
     string options = (optimizationFlags == NULL ? defaultOptimizationOptions : string(optimizationFlags));
     stringstream src;
@@ -369,10 +392,11 @@ CUmodule CudaContext::createModule(const string source, const map<string, string
     string bits = intToString(8*sizeof(void*));
 #ifdef WIN32
     string command = ""+compiler+" --ptx --machine "+bits+" -arch=sm_"+gpuArchitecture+" -o "+outputFile+" "+options+" "+inputFile+" 2> "+logFile;
+    int res = compileInWindows(command);
 #else
     string command = "\""+compiler+"\" --ptx --machine "+bits+" -arch=sm_"+gpuArchitecture+" -o \""+outputFile+"\" "+options+" \""+inputFile+"\" 2> \""+logFile+"\"";
-#endif
     int res = std::system(command.c_str());
+#endif
     try {
         if (res != 0) {
             // Load the error log.