Fix compiler assert. #585
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Fix compiler assert. #585
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This change fixes the compiler assert reported in Github issue #575. We are inserting temporary variables for strings so that we can describe their bounds. The assert was checking that we don't compute a temporary variable more than once in an expression. The problem is that we are copying the expression that creates and binds the temporary into the bounds. The bounds is used at runtime in the dynamic_bounds_cast. This causes the temporary to computed twice, which is what the assert is protecting against. Since we've already computed the value into a temporary, the fix is to replace the binding with a read of the temporary. Testing: - Added simple repro case that caused a compiler crash. - Passed local testing and repro case. Still needs a runtime test that the right thing is happening.
dtarditi
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to microsoft/checkedc
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Nov 3, 2018
There was a compiler assert on a dynamic_bounds_cast of a string literal (microsoft/checkedc-clang#575). This is fixed by microsoft/checkedc-clang#585. Add runtime tests that check that the right results are being computed in this case.
sulekhark
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Jul 8, 2021
Iterate over a BoundsKey set instead of a ProgramVar* set so that the iteration order does not depend on the address of the program variables. This fixes the issue, but it is still potentially a problem that the function depends on the order it iterations over the bounds keys. It is also likely that other loops over sets of pointers exbibit this same problem.
This was referenced Jan 15, 2022
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This change fixes the compiler assert reported in Github issue #575. We are inserting temporary variables for strings so that we can describe their bounds. The assert was checking that we don't compute a temporary variable more than once in an expression.
The problem is that we are copying the expression that creates and binds the temporary into the bounds. The bounds is used at runtime in the dynamic_bounds_cast. This causes the temporary to be computed twice, which is what the assert is protecting against. Since we've already computed the value
into a temporary, the fix is to replace the binding with a read of the temporary.
Testing: