[PATCH] D59553: [LLD][ELF][DebugInfo] llvm-symbolizer shows incorrect source line info if --gc-sections used

[Alexey Lapshin via Phabricator via llvm-commits]

avl added a comment.



> Existing tools have learned various heuristics to avoid 0 DW_AT_low_pc collision, but I am not sure what they'd do if those relocations resolve to -1. llvm-symbolizer is certainly good (I have checked a few >examples - I'm learning it recently), but what about other tools?

addr2line started to behave correctly :

[LD]clang++ -gdwarf-5 -O -Wl,--gc-sections -fuse-ld=ld not_used.o main.o -o res.out
addr2line -e res.out 0x400497
/home/avl/bugs/gc_debuginfo/not_used.cpp:2 <<<<<<<<<<<<<<<<<<<<<<<<<< incorrect if built by ld

[LLD]clang++ -gdwarf-5 -O -Wl,--gc-sections -fuse-ld=lld not_used.o main.o -o res.out
addr2line -e res.out 0x2010e7  
/home/avl/bugs/gc_debuginfo/main.cpp:3  <<<<<<<<<<<<<<<<<<<<<<< correct if built by lld with this patch


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  https://reviews.llvm.org/D59553/new/

https://reviews.llvm.org/D59553