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ISA handlers #21

Open emesare opened 2 hours ago

emesare commented 2 hours ago

Masking of instructions requires us to know that a constant is a pointer to a relocatable section. The issue is that in many RISCy architectures the pattern for loading a pointer will be split across multiple instructions. Identifying this pattern is very error prone if not done on an ISA level.

We should provide a way to register ISA specific handlers that can mask out instructions. This complicates the basic block GUID generation, however these functions wouldn't match regardless because the relocatable instructions weren't masked.

emesare commented 2 hours ago

An example of the split pointer arithmetic from TriCore:

00000074  911000f8   movh.a  a15, 0x8001
00000078  d9ff6c38   lea     a15, a15, -0x7b14  {0x800084ec}
emesare commented 2 hours ago

Another path forward is utilizing Binary Ninja's MLIL that would be able to identify these patterns and simplify them down to a constant pointer, the issue is that it is not portable. IDA and Ghidra would not be able to replicate that behavior.