On 2018-12-30 17:58 +0800, Remus Clearwater wrote: > > B is correct. We don't care about function pointers because we know if a > > static function has its address takes in the same compilation unit in > > which it appears. If it has not had its address taken, we don't have > > to care about the system ABI. If it has, then we need to use the system > > ABI. > > If the address of the static function been taken and then we need to use > > the > > system ABI. > > Does such action has been documented somewhere inside GCC or as an > undocumented convention? Or further, even as an undocumented convention > inside all the many mainstream C compilers (GCC, clang ...)? The compiler must obey the C standard and this is the reasonable way to make it so. > Furthermore, could I make the following conclusion under GCC and Linux? > Conclusion: > > For the "calling" of the C static functions, it has only two > possibilities -- either it's been inlined by the compiler optimization > (i.e. not actually been called by the `call` instruction but been optimized > for the reason of speed), Or it would be actually called (with the `call` > instruction) under the "Function Calling Sequence" constraints which have > been described in the Sys V ABI specs (same as the calling of those extern > C functions). No. The compiler may use customized calling convention to maximize the performance unless this function may be called in other translation units. -- Xi Ruoyao <xry111@xxxxxxxxxxxxxxxx> School of Aerospace Science and Technology, Xidian University
