Support composite function member locations

[emesare]

warp/type.fbs

Lines 164 to 166 in c9cfe5b

	union LocationClass {
	// TODO: Register can have multiple fields?
	RegisterLocation,

Describes a set of locations that represent a composite location.

table LocationPiece {
    location: LocationClass; 
    width: BitSize; 
    storage_offset: BitOffset;
    location_offset: BitOffset;
}

table CompositeLocation {
    pieces: [LocationPiece];
}

union LocationClass {
    RegisterLocation,
    StackLocation,
    CompositeLocation,
}

Something like this seems reasonable, storage_offset describes the offset into the data, whereas location_offset describes the offset into the location. We need storage_offset to match the pieces with the parts of the data they refer to, and we need location_offset to pack multiple pieces into a given location.

Some semi relevant links:

• https://github.com/bytecodealliance/wasmtime/blob/809bd7e72d80bf9e20b235d770b890ed63c2410e/cranelift/codegen/src/isa/x64/abi.rs#L94
• https://github.com/rust-lang/rustc_codegen_cranelift/blob/f4bb7d1de119964e63a7090c1e143cdab13143fa/src/abi/pass_mode.rs#L112-L122
• https://github.com/NationalSecurityAgency/ghidra/blob/master/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/listing/VariableStorage.java
  • https://github.com/NationalSecurityAgency/ghidra/blob/master/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/listing/LocalVariableImpl.java