[all-commits] [llvm/llvm-project] 339b34: [AVR] Respect the 'interrupt' function attribute

[Dylan McKay via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 339b34266c1b54a9b5ff2f83cfb1da9cd8c9d90a
      https://github.com/llvm/llvm-project/commit/339b34266c1b54a9b5ff2f83cfb1da9cd8c9d90a
  Author: Dylan McKay <me at dylanmckay.io>
  Date:   2020-03-31 (Tue, 31 Mar 2020)

  Changed paths:
    M llvm/lib/Target/AVR/AVRFrameLowering.cpp
    M llvm/lib/Target/AVR/AVRISelLowering.cpp
    M llvm/lib/Target/AVR/AVRMachineFunctionInfo.h
    M llvm/lib/Target/AVR/AVRRegisterInfo.cpp
    M llvm/test/CodeGen/AVR/interrupts.ll

  Log Message:
  -----------
  [AVR] Respect the 'interrupt' function attribute

In the past, AVR functions were only lowered with interrupt-specific
machine code if the function was defined with the "avr-interrupt" or
"avr-signal" calling conventions.

This patch modifies the backend so that if the function does not have a
special calling convention, but does have an "interrupt" attribute,
that function is interpreted as a function with interrupts.

This also extracts the "is this function an interrupt" logic from
several disparate places in the backend into one AVRMachineFunctionInfo
attribute.

Bug found by Wilhelm Meier.