Improve Jump Table Symbolization Algorithm #36
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I observed that RetroWrite missed some jump table entries when they refers to the function boundary. The following assembly code that gcc-9 compiler emitted represents the error case. Since the second jump table entry refers to label .LBB38_624, which was defined at the function boundary, RetroWrite misses 6 jump table entries. I added is_located_at_the_end_of_function() method to check function boundary and define additional label to symbolize jump table entry. Also, I revised symbolize_switch_tables() method to resolve the error. ``` get_machine_flags: # ... leaq .LJTI38_6(%rip), %rax movslq (%rax,%r15,4), %rcx addq %rax, %rcx jmpq *%rcx # ... jmp .LBB38_535 #end of get_machine_flags .LBB38_624: .cfi_endproc .LJTI38_6: .long .LBB38_47-.LJTI38_6 .long .LBB38_624-.LJTI38_6 # Miss .long .LBB38_355-.LJTI38_6 # Miss .long .LBB38_624-.LJTI38_6 # Miss .long .LBB38_360-.LJTI38_6 # Miss .long .LBB38_624-.LJTI38_6 # Miss .long .LBB38_353-.LJTI38_6 # Miss ```
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I observed that RetroWrite missed some jump table entries when they refers to
the function boundary. The following assembly code that gcc-9 compiler emitted
represents the error case. Since the second jump table entry refers to label
.LBB38_624, which was defined at the function boundary, RetroWrite misses 6
jump table entries.
I added is_located_at_the_end_of_function() method to check function boundary
and define additional label to symbolize jump table entry. Also, I revised
symbolize_switch_tables() method to resolve the error.