[CherryPick][DWARFVerifier] Fix verification of empty line tables (#81162) #8163
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A line table whose sole entry is an end sequence should not have the entry's file index verified, as that value corresponds to the initial value of the state machine, not to a real file index. In DWARF 5, this is particularly problematic as it uses 0-based indexing, and the state machine specifies a starting index of 1; in other words, you'd need to have _two_ files before such index became legal "by default". A previous attempt to fix this problem was done [1], but it was too specific in its condition, and did not capture all possible cases where this issue can happen. [1]: llvm#77004 (cherry picked from commit 1d4fc38)
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A line table whose sole entry is an end sequence should not have the entry's file index verified, as that value corresponds to the initial value of the state machine, not to a real file index. In DWARF 5, this is particularly problematic as it uses 0-based indexing, and the state machine specifies a starting index of 1; in other words, you'd need to have two files before such index became legal "by default".
A previous attempt to fix this problem was done 1, but it was too specific in its condition, and did not capture all possible cases where this issue can happen.
(cherry picked from commit 1d4fc38)