This patch allows to get function frame size from the .llvm_stackmaps section.
This section was generated for those functions that have at least one stack map record. For the other functions we could not get frame size. (The .eh_frame section does not help. Any other way?).
The StackMap class collected functions when stack map records were added. This patch introduces method StackMap::registerFunction() that is called before adding stack map records. All registered functions will have records with their frame sizes in the stack map section if the new option -stackmap-force-serialization is set to true even if there is no stack map records. With -stackmap-force-serialization set to false (the default) the old behavior is used: only those functions that have at least one record get into the stack map section and the section is generated only if there is at least one such function.