Type the operand of code_declt #3267
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kroening
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Nov 3, 2018
kroening
commented
- Each commit message has a non-empty body, explaining why the change was made.
- n/a Methods or procedures I have added are documented, following the guidelines provided in CODING_STANDARD.md.
- Regression or unit tests are included, or existing tests cover the modified code (in this case I have detailed which ones those are in the commit message).
- n/a My commit message includes data points confirming performance improvements (if claimed).
- My PR is restricted to a single feature or bugfix.
- White-space or formatting changes outside the feature-related changed lines are in commits of their own.
kroening
requested review from
cesaro,
chrisr-diffblue,
cristina-david,
martin-cs,
NathanJPhillips,
peterschrammel,
pkesseli,
smowton and
thk123
as code owners
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This PR failed Diffblue compatibility checks (cbmc commit: f537e7c).
Build URL: https://travis-ci.com/diffblue/test-gen/builds/90172916
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Please contact @peterschrammel, @thk123, or @allredj for support.
Common spurious failures:
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The incompatibility may have been introduced by an earlier PR. In that case merging this
PR should be avoided unless it fixes the current incompatibility.
| { | ||
| symbol_exprt tmp(symbol.name, symbol.type); | ||
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| if(symbol.is_lvalue) | ||
| tmp.set(ID_C_lvalue, true); | ||
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| return std::move(tmp); | ||
| return tmp; |
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Why is the std::move being removed here?
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Perhaps counterintuitively, the std::move prevents a move here. I.e., removing it enables copy elision.
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Why would that be the case? Notably, clang-7 had complained about the absence of std::move here, and it has just been introduced in 72bfc35.
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@tautschnig the key is whether a type conversion is required or not. Previously we returned a symbol_exprt, meaning we needed a conversion to exprt (via its copy- or move-constructor), so std::move was a good thing (picking the move constructor). Now we return a symbol_exprt, meaning no type conversion is necessary and RVO / copy/move-elision is possible, so std::move is now a bad thing.
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Many thanks for the elaboration!
src/goto-instrument/dump_c.cpp
Outdated
| @@ -894,7 +894,9 @@ void dump_ct::convert_global_variable( | |||
| } | |||
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| if(!func.empty() && !symbol.is_extern) | |||
| local_static_decls[symbol.name]=d; | |||
| { | |||
| local_static_decls.insert(std::pair<irep_idt, code_declt>(symbol.name, d)); | |||
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I think that's fine, but I am surprised to see this seemingly unrelated change in here. And then .emplace would seem better?!
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It's related as follows: the PR enforces that a code_declt always has a symbol_typet parameter, which is not the case for a very brief time when using [] to insert an element into a map.
But will use .emplace.
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This PR failed Diffblue compatibility checks (cbmc commit: 35b893c).
Build URL: https://travis-ci.com/diffblue/test-gen/builds/90241109
Status will be re-evaluated on next push.
Please contact @peterschrammel, @thk123, or @allredj for support.
Common spurious failures:
- the cbmc commit has disappeared in the mean time (e.g. in a force-push)
- the author is not in the list of contributors (e.g. first-time contributors).
The incompatibility may have been introduced by an earlier PR. In that case merging this
PR should be avoided unless it fixes the current incompatibility.
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Needs a rebase. |
tautschnig
assigned kroening and unassigned peterschrammel, martin-cs and chrisr-diffblue
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Passed Diffblue compatibility checks (cbmc commit: e889df7).
Build URL: https://travis-ci.com/diffblue/test-gen/builds/90402530
