Suppress relaxations for incomplete script symbols #276
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A symbol may be defined in a script referencing a section address. Such symbols get their values after section layout is complete. At the relaxation time such symbols do not have the correct value. The current logic uses a value of zero as an indicator that the symbol value is unknown and prevents some relaxations with them. However, this logic produces both false positives and false negatives because 1) incomplete symbol values may be used in expressions that produce a nonzero value and 2) some symbols having a zero value are valid and can be relaxed. In this change, symbols that reference unknows section addresses are detected and the corresponding relaxations are not performed.
Contributor
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Relaxation tests have not been updated. |
Member
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Thanks! This looks about right, but testing will prove that. |
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A symbol may be defined in a script referencing a section address. Such symbols get their values after section layout is complete. At the relaxation time such symbols do not have the correct value. The current logic uses a value of zero as an indicator that the symbol value is unknown and prevents some relaxations with them. However, this logic produces both false positives and false negatives because 1) incomplete symbol values may be used in expressions that produce a nonzero value and 2) some symbols having a zero value are valid and can be relaxed.
In this change, symbols that reference unknows section addresses are detected and the corresponding relaxations are not performed.