C front-end: reject code containing duplicate labels #6496
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tautschnig
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kroening
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NlightNFotis
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| if(!labels_defined.emplace(code.get_label(), code.source_location()).second) | ||
| { | ||
| error().source_location = code.source_location(); | ||
| error() << "duplicate label '" << code.get_label() << "'" << eom; |
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💡 Can this be substituted for a throw of an invalid_source_file_exceptiont from src/utils/exception_utils.h? That would be great!
An upcoming change will enforce per-function unique labels, as mandated by the C standard. We were sometimes sloppy about this with __CPROVER_ASYNC_* pseudo-labels as they don't actually indicate jump targets.
Whitespace changes only.
We previously silently accepted such code, maintaining the labels and attaching them to multiple instructions. `goto` resolved to the first such occurrence of the label. GCC firmly rejects such code.
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Codecov Report
@@ Coverage Diff @@
## develop #6496 +/- ##
===========================================
+ Coverage 76.06% 76.27% +0.20%
===========================================
Files 1546 1546
Lines 165584 165624 +40
===========================================
+ Hits 125951 126325 +374
+ Misses 39633 39299 -334
Continue to review full report at Codecov.
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We previously silently accepted such code, maintaining the labels and
attaching them to multiple instructions.
gotoresolved to the firstsuch occurrence of the label.
GCC firmly rejects such code.