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22 lines
1.1 KiB
Markdown
22 lines
1.1 KiB
Markdown
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# Line number information
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Line number information maps between machine code instructions and the source level location.
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## Encoding
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The line number information is stored in the `.debug_line` section for ELF and `__debug_line`
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section of the `__DWARF` segment for Mach-O object files. The line number information contains a
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header followed by the line program. The line program is a program for a virtual machine with
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instructions like set line number for the current machine code instruction and advance the current
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machine code instruction.
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## Tips
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You need to set either `DW_AT_low_pc` and `DW_AT_high_pc` **or** `DW_AT_ranges` of a
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`DW_TAG_compilation_unit` to the range of addresses in the compilation unit. After that you need
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to set `DW_AT_stmt_list` to the `.debug_line` section offset of the line program. Otherwise a
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debugger won't find the line number information. On macOS the debuginfo relocations **must** be
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section relative and not symbol relative.
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See [#303 (comment)](https://github.com/bjorn3/rustc_codegen_cranelift/issues/303#issuecomment-457825535)
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for more information.
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