Re: [Dwarf-Discuss] variable locations - safe use as lvalues

2020-01-20 Thread Michael Eager via Dwarf-Discuss
On 1/20/20 6:21 PM, Frank Ch. Eigler via Dwarf-Discuss wrote: Complication 2: The compiler reuses variable locations at the same PC. This seems to be a compiler bug. (Actually, this could be a valid optimization, e.g.: int a = expression; int b = expression; >

Re: [Dwarf-Discuss] variable locations - safe use as lvalues

2020-01-20 Thread Frank Ch. Eigler via Dwarf-Discuss
Hi - > > - ... and undoubtedly other complications exist! > > Interesting question. Thanks! We have been thinking in similar directions generally as y'all. > Complication 2: The compiler reuses variable locations at the same PC. This > seems to be a compiler bug. (Actually, this could be

Re: [Dwarf-Discuss] variable locations - safe use as lvalues

2020-01-20 Thread Michael Eager via Dwarf-Discuss
On 1/20/20 2:20 PM, Frank Ch. Eigler via Dwarf-Discuss wrote: Hi - I have a question about variable location lists, but not their encoding, the use they are suitable for. The basic debugging scenario is just reading variable values, for which this is fine, especially when high-quality

Re: [Dwarf-Discuss] variable locations - safe use as lvalues

2020-01-20 Thread Cary Coutant via Dwarf-Discuss
> A debugger cannot currently be told that any particular variable > location expression is safe to use as an lvalue, something roughly > "exclusive, exhaustive, -O0-equivalent". I believe most debuggers > don't even handle the multiple-locations case for writes at all. I > don't know why -

[Dwarf-Discuss] variable locations - safe use as lvalues

2020-01-20 Thread Frank Ch. Eigler via Dwarf-Discuss
Hi - I have a question about variable location lists, but not their encoding, the use they are suitable for. The basic debugging scenario is just reading variable values, for which this is fine, especially when high-quality compilers emit exquisitely detailed data for their optimized code. But