[all-commits] [llvm/llvm-project] a095d1: Fix an assertion failure in DwarfExpression's subr...

[adrian-prantl via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: a095d149c2c82f9f13bd2ec5597a9e3f257b14c6
      https://github.com/llvm/llvm-project/commit/a095d149c2c82f9f13bd2ec5597a9e3f257b14c6
  Author: Adrian Prantl <aprantl at apple.com>
  Date:   2020-01-27 (Mon, 27 Jan 2020)

  Changed paths:
    M llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
    M llvm/lib/CodeGen/AsmPrinter/DwarfExpression.h
    A llvm/test/DebugInfo/MIR/ARM/subregister-full-piece.mir

  Log Message:
  -----------
  Fix an assertion failure in DwarfExpression's subregister composition

This patch fixes an assertion failure in DwarfExpression that is
triggered when a complex fragment has exactly the size of a
subregister of the register the DBG_VALUE points to *and* there is no
DWARF encoding for the super-register.

I took the opportunity to replace/document some magic values with
static constructor functions to make this code less confusing to read.

rdar://problem/58489125

Differential Revision: https://reviews.llvm.org/D72938