aot_reloc_x86_64: Fix pointer overflows #809
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Detected by UBSan ``` /root/src/wasm-micro-runtime/core/iwasm/aot/arch/aot_reloc_x86_64.c:232:43: runtime error: addition of unsigned offset to 0x000041209004 overflowed to 0x000041209000 SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior /root/src/wasm-micro-runtime/core/iwasm/aot/arch/aot_reloc_x86_64.c:232:43 in ```
| ((uint8 *)symbol_addr + reloc_addend | ||
| - (target_section_addr + reloc_offset)); | ||
| ((uintptr_t)symbol_addr + reloc_addend | ||
| - (uintptr_t)(target_section_addr + reloc_offset)); |
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Shall we also fix other places, e.g. L168-L170?
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And not known which expression causes integer overflow? target_section_addr + reloc_offset, plt + reloc_addend, or (plt + reloc_addend - (target_section_addr + reloc_offset))? Here the type of plt and target_section_addr is uint8 *, the range is 0 ~ 2^64-1 in x86-64, a little confused why there is integer overflow, could you please give an example as there might be some other places to be fixed?
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- iirc, pointer overflows like these are undefined behavior in C. unsigned integer overflows are ok.
- i haven't checked other places. i just fixed a few places which actually got complaints from UBSAN during my tests.
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OK, so the code inserted by the compiler detected pointer overflow and reported error, from the output log runtime error: addition of unsigned offset to 0x000041209004 overflowed to 0x00004120900 ... aot_reloc_x86_64.c:232:43，the overflow should occur at (uint8 *)symbol_addr + reloc_addend. We will merge this PR firstly and check whether there are other places to fix. Thanks a lot!
aot_reloc_x86_64: Fix pointer overflows (#809)
Fix pointer overflow of `(uint8 *)symbol_addr + reloc_addend` detected by UBSan: ``` core/iwasm/aot/arch/aot_reloc_x86_64.c:232:43: runtime error: addition of unsigned offset to 0x000041209004 overflowed to 0x000041209000 SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior core/iwasm/aot/arch/aot_reloc_x86_64.c:232:43 ```
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