Am 12.12.2011 16:58, schrieb Paul Brook: >>> Trying to make a 32-bit target "64-bit safe" without actually >>> implementing the 64-bit target is a complete waste of time. >> >> That's where we disagree. I rather do things right from the start than >> leaving the cleanup work to someone else later on. >> >>> You've almost no chance of getting >>> it right. In some cases the correct answer will be to use 32-bit >>> arithmetic, then sign/zero extend the result. In other cases the correct >>> answer will be to perform word size arithmetic. Blindly picking one >>> just makes the bugs harder to find later. >> >> This series picks nothing blindly. > > Sure it does [snip]
No, start by reading the git summary. These four patches don't touch target-* at all. This is intentionally NOT some Coccinelle script running wild doing refactorings. That's what I would call "blindly". > Ther are three ways to resolve a mismatch: > - Change everything to TCGv_i32. > - Change everything to TCGv. > - Add an explicit extension/truncation (compiles to no-op on 32-bit targets). > > There's no way of the developer of a 32-bit architecture to know [snip] Again, that's where we disagree: The whole point of TCGv and tl is to have variable-sized operations scaling with target_long. Thus, using them for fixed-size i32 or i64 operations is a semantic error by definition. Whether or not an i64 target exists. And I certainly don't want to knowingly introduce semantic errors in my new code just so that at another time someone else can use that to review a 64-bit port. That's just plain stupid. As the developer I must know what semantics I am implementing for my target. Note that the three choices are independent of this series, same holds without. The difference is, my series offers a way to *flag* cases where this has been ignored. >> If you have a better proposal how to introduce the checks I want, please >> let us hear it. > I still don't understand how your additional restructions are ever useful. > Please give an example of an actual error your checks will catch. My stated requirement is that I want to detect ALL uses of TCGv_i32 with tl functions and all uses of TCGv with i32 functions, be it an error or a warning. Whether or not such consistency seems useful to you. I have already given four examples to Peter, that you quoted previously. Consider a uint32_t 8-bit status register on a 20-bit architecture - it never scales to i64 so I know that TCGv/tl is definitely wrong! Either point out something that's technically wrong with these patches and I'll gladly fix it, or, again, propose a constructive solution. Reappearing after a year and destructively objecting to patches is something we've been through before. Thanks, Andreas
