[linker-script] Error when dot assignment exceeds UINT32_MAX

[deepakshirkem]

Problem

Fixes #386

ELD assigns incorrect addresses when the padding due to dot assignment is greater than UINT32_MAX. When a linker script uses: . = . + 0x400000000;

Fix

Added validation in Assignment::assign() to error out when dot assignment creates padding that exceeds UINT32_MAX
as such large padding values are not meaningful.

Testing

Added test DotAssignmentOverflow that verifies ELD emits a clear error when dot assignment value exceeds UINT32_MAX.

cc @quic-seaswara @parth-07

[parth-07]

Hi @deepakshirkem,

Thank you for the pull-request. The original issue does not state that we should error-out if the padding due to dot assignment is greater than UINT32_MAX, instead it is about the symbol values being incorrect when there is a huge padding. Erroring out when there is a huge padding is a workaround and not a fix for this issue. The huge padding in the original issue can be replaced by any other huge-content that takes up space in the image layout and we will still see the same issue.

[deepakshirkem]

Hi @parth-07,
I have implemented the root cause fix in PR #1108 by changing uint32_t → uint64_t for Fragment::UnalignedOffset to correctly handle 64-bit offsets. Could you please confirm if this approach is correct? If so, I can implement that fix into this PR.