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Return structs from functions #14

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DontBelieveMe opened this issue Jan 7, 2022 · 0 comments
Open

Return structs from functions #14

DontBelieveMe opened this issue Jan 7, 2022 · 0 comments
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codegen Machine/Assembly Code Generation enhancement New feature or request ir Relating to the IR

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Returning structs needs some special handling, see Parameter Passing - AAPCS32

https://github.com/ARM-software/abi-aa/blob/main/aapcs32/aapcs32.rst#64result-return

In short:

  • If it's smaller than (or equal to) 4 bytes in size (native register size) then it is stored directly in the r0 register (sign or zero extended if nessesary)
  • If it's larger than 4 bytes then the value is stored in memory and the address of that value is passed to the called function as a parameter (in r0)
@DontBelieveMe DontBelieveMe self-assigned this Jan 7, 2022
@DontBelieveMe DontBelieveMe added enhancement New feature or request ir Relating to the IR codegen Machine/Assembly Code Generation labels Jan 7, 2022
DontBelieveMe added a commit that referenced this issue Jan 11, 2022
@DontBelieveMe
Work on #14, can now return small (<= 4 bytes) structs from functions
57fd952
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