5 ms·

> debuggers will often lie to you, and you often have to look into the registers for the real data What do you mean by this?

gambiting 10y ago
Well I don't know what OP meant, but I work in games programming, and the PS4 debugger will frequently lie to you in visual studio. You hover over a variable and it's just giving you a completely wrong value, which is correct if you look directly into memory window or assembly view. I wouldn't consider this to be a very common use case though, it's a niche within niche.
- SticksAndBreaks 10y ago
  Its that way in all the niches, which makes it a set of all niches ==> mainstream thing.
  - duncanawoods 10y ago
    Optimised C++ sure but you don't see this issue with C#. If you are using a high-level language that does not have a reliable debugger, time to change language.
    - ska 10y ago
      One of the things that happens here is the more static and optimized a compiler output is, the harder it is to do source level debugging. Conversely, more dynamic, less optimized languages are easier to write and verify debuggers for. This isn't a strict ordering, of course, but a general trend. Unfortunately, the very aspect that make some languages easier to debug make them poor at some of the applications you might want the former for (cf C# and c++ as you bring up). Luckily debugging is not merely the act of using a debugger !
    - pjmlp 10y ago
      I imagine this situation might surface when looking at optimized native code, either from JIT or AOT, for example via WinDbg sos plugin for .NET. Still not a reason enough to avoid using a debugger.
SticksAndBreaks 10y ago
Debuggers sometimes simply write wrong values into those nice gui-windows- do not update the values they show, or just dont inform the reader that the value ceased to exist- at all.
- jnordwick 10y ago
  Oh, so a bug in the debugger basically. Speaking of the registers it sounded like he was talking about some weird cache incoherency issue that shouldn't conceivably exist (on x86 at least).
deleted 10y ago
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gambiting 10y ago

Well I don't know what OP meant, but I work in games programming, and the PS4 debugger will frequently lie to you in visual studio. You hover over a variable and it's just giving you a completely wrong value, which is correct if you look directly into memory window or assembly view. I wouldn't consider this to be a very common use case though, it's a niche within niche.

SticksAndBreaks 10y ago
Its that way in all the niches, which makes it a set of all niches ==> mainstream thing.
- duncanawoods 10y ago
  Optimised C++ sure but you don't see this issue with C#. If you are using a high-level language that does not have a reliable debugger, time to change language.
  - ska 10y ago
    One of the things that happens here is the more static and optimized a compiler output is, the harder it is to do source level debugging. Conversely, more dynamic, less optimized languages are easier to write and verify debuggers for. This isn't a strict ordering, of course, but a general trend. Unfortunately, the very aspect that make some languages easier to debug make them poor at some of the applications you might want the former for (cf C# and c++ as you bring up). Luckily debugging is not merely the act of using a debugger !
  - pjmlp 10y ago
    I imagine this situation might surface when looking at optimized native code, either from JIT or AOT, for example via WinDbg sos plugin for .NET. Still not a reason enough to avoid using a debugger.

SticksAndBreaks 10y ago

Debuggers sometimes simply write wrong values into those nice gui-windows- do not update the values they show, or just dont inform the reader that the value ceased to exist- at all.

jnordwick 10y ago
Oh, so a bug in the debugger basically. Speaking of the registers it sounded like he was talking about some weird cache incoherency issue that shouldn't conceivably exist (on x86 at least).

deleted 10y ago

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