[all-commits] [llvm/llvm-project] 8270a9: [lldb] Scalar re-fix UB in float->int conversions

[Pavel Labath via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 8270a903baf55122289499ba00a979e9c04dcd44
      https://github.com/llvm/llvm-project/commit/8270a903baf55122289499ba00a979e9c04dcd44
  Author: Pavel Labath <pavel at labath.sk>
  Date:   2020-07-01 (Wed, 01 Jul 2020)

  Changed paths:
    M lldb/source/Utility/Scalar.cpp
    M lldb/unittests/Utility/ScalarTest.cpp

  Log Message:
  -----------
  [lldb] Scalar re-fix UB in float->int conversions

The refactor in 48ca15592f1 reintroduced UB when converting out-of-bounds
floating point numbers to integers -- the behavior for ULongLong() was
originally fixed in r341685, but did not survive my refactor because I
based my template code on one of the methods which did not have this
fix.

This time, I apply the fix to all float->int conversions, instead of
just the "double->unsigned long long" case. I also use a slightly
simpler version of the code, with fewer round-trips
(APFloat->APSInt->native_int vs
APFloat->native_float->APInt->native_int).

I also add some unit tests for the conversions.