read DW_OP_deref_size address through FIRCLSReadMemory

[isl-Ramzi]

Unvalidated memory read in DW_OP_deref_size

DW_OP_deref pops its address and reads it through FIRCLSReadMemory, but DW_OP_deref_size dereferences the popped value directly, so a DW_CFA_expression in a frame's eh_frame can steer the crash-time unwinder into an arbitrary-address read. Routed it through the same validated read as DW_OP_deref, so valid reads are unchanged and a bad address is reported instead of faulting. Added two regression tests covering a valid read and an unreadable address.

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[paulb777]

/gemini review

[gemini-code-assist]

Code Review

This pull request refactors the DW_OP_deref_size opcode execution in the DWARF expression machine to safely read memory using FIRCLSReadMemory instead of directly dereferencing potentially invalid pointers. Additionally, it introduces unit tests to verify that valid addresses are read correctly and invalid addresses are safely rejected without causing crashes. There are no review comments, and I have no additional feedback to provide.

[ncooke3]

Rerunning failed CI job...

[ncooke3]

Thanks!