2018-05-15 18:13:09 +02:00
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# Dwarf-assembly
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Generates C code from the DWARF embedded in an ELF file. This code can then be
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compiled into a .so, and used to unwind stack frames.
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## Options
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### Switch generation policy
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The code can either generate one big `switch` statement for every PC in the
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ELF, or one `switch` and a function per FDE, plus a lookup function.
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One of the two options must be passed:
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* `--switch-per-func`: one `switch` and function per FDE;
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* `--global-switch`: a single big `switch` for the whole ELF.
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### PC list
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Instead of generating interval switches (eg `case 0x42 ... 0x100`), it is
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possible to provide a binary file (generated by `../extract_pc.py`) containing
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a list of all PCs in the ELF. The file contains one 8-bytes chunk per PC,
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which is the PC in little endian.
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`--pc-list PC_LIST_FILE_PATH`
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2018-06-01 19:46:43 +02:00
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### Dereferencing function
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The lookup functions can also take an additional argument, a pointer to a
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function of prototype
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```C
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uintptr_t deref(uintptr_t address)
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```
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that will, in spirit, contain a `return *((uintptr_t*)address);`.
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This argument can be used to work on remote address spaces instead of local
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address spaces, eg. to work with `libunwind`.
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To enable the presence of this argument, you must pass the option
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`--enable-deref-arg`
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