The IDE has been designed to allow different technologies to be used automatically to generate tasks for different types of processor. The most obvious example of this is to allow a task to be placed on a DSP or an FPGA. Even on DSPs there is considerable scope for variation, as can been seen with the TI C6000 family of DSPs where various integer and floating point implementations need to be built with different options. Normally the technology used for a task is hidden and users can ignore the issue, but when different variants of tasks are needed it is necessary to deal with it explicitly. If you expand a DSP task in the Diamond source view and then click the Switch display mode icon at the top right of that display, the technology grouping structure is revealed.
Inside the upc task, you can see that all of the source files are actually inside the ti group of a c group. Below the task files is another group for C6455 processors. The location of a file in this structure of groups determines how specific it is to a particular technology; the deeper in the hierarchy, the more specific the source file. If we change the type of the processor root to be an SMT376 and rebuild, a new group is created.
c6713 contain all the built components that are relevant to c6713 processors. Because the source files are above these processor-specific groups, the same files are used for each processor type, only the compile and link options are different. If you require source changes that depend on the processor technology being used, you can put versions of the relevant files inside the relevant group and they will be used in those specific contexts.
Moving the task onto an FPGA processor causes a completely new technology grouping to be added to the structure.
Now we have a vhdl group which contains groups relevant to that technology. Note that this process simply selects different sets of files; it does not convert from C source to VHDL or vice versa.