I frequently cannot contribute discussion to Cygwin topics, but due to my work porting a database (fis-gtm) to Cygwin, I can chime in here.
This is a good article to give you an overview of the different calling conventions out there: https://eli.thegreenplace.net/2011/09/06/stack-frame-layout-on-x86-64. Here's a summary of what I learned: 1. Cygwin x32 and Linux x32 use the same assembly layout--application binary interface (ABI). 2. Cygwin x64 uses the Windows 64 ABI. Linux x64 uses the AMD64 ABI. This tutorial article is a good place to learn about x64 ABI for Linux: https://cs.lmu.edu/~ray/notes/gasexamples/. --Sam On Sun, Apr 28, 2019 at 4:00 PM Eliot Moss <m...@cs.umass.edu> wrote: > > On 4/26/2019 5:04 PM, Jesse Thompson wrote: > > > Ultimately what I am trying to research is how to begin building a simple > > compilation system of my own, so how do the *makers* of compilers deal with > > these differences in calling convention? > > They make parts of the compilers conditional on the overall platform. > For example, if a compiler is written in C / C++, they use #define > and #if tests, and may include different modules in a build, etc. > > They also try to code various algorithms, such a register allocation, > to be parameterized by a description of how things work on a given > platform. > > There are whole swaths that are essentially target independent, > especially those having to do with higher level optimizations. > However, even there, platform differences may lead to different > parameter settings (e.g., default number of times to unroll a > loop) or strategies (presence / absence of vector units and > of predicated instructions (as on the ARM) affect how you want > to generate even the high-level target-independent code). > > In the case that you are talking about, most of the code generation > and optimization strategies are the same -- there are just some > fine points different about calling sequences, register usage > conventions, etc. I think those are mostly addressed by the kind > of parameterization-by-descriptions (or by #defines) that I have > described. > > You may still see somewhat different code from different compilers, > even for the same platform, simply because the different designers > chose different base code sequences - which may be equivalent. For > example, to move a constant into a register, add-immediate (adding > to zero) and or-immediate (again, ORing with zero) give the same > result for many arguments, to the choice is arbitrary. One can > come up with many such examples. > > Supporting multiple target instruction sets, or even the range of > models of the x86 line, requires some amount of platform-specific > work, of course, and lot of attention to how to build components > that are either independent of the ISA or retargetable in some way. > > Regards - Eliot Moss > > -- > Problem reports: http://cygwin.com/problems.html > FAQ: http://cygwin.com/faq/ > Documentation: http://cygwin.com/docs.html > Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple > -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
