[all-commits] [llvm/llvm-project] c9fce5: X86: adjust the windows 64 calling convention for ...

[Saleem Abdulrasool via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: c9fce5f0c3a82cf037c288e840d857066aab75af
      https://github.com/llvm/llvm-project/commit/c9fce5f0c3a82cf037c288e840d857066aab75af
  Author: Saleem Abdulrasool <compnerd at compnerd.org>
  Date:   2021-03-13 (Sat, 13 Mar 2021)

  Changed paths:
    M llvm/lib/Target/X86/X86CallingConv.td
    A llvm/test/CodeGen/X86/swiftself-win64.ll

  Log Message:
  -----------
  X86: adjust the windows 64 calling convention for Swift

Adjust the Win64 calling convention for Swift to pass self in R13, which
is traditionally a CSR.  This makes the behaviour similar to the SysV CC
for Swift as well.  This should improve the argument passing on Windows,
although it comes at a high cost of ABI incompatibility.  Fortunately in
this case, there is no guarantee of ABI stability, and so we can make
this incompatible change.