Fangrui Song bf67610a8a [MC] Rename temporary symbols of empty name to ".L0 " (#89693) ...

Temporary symbols generated for .eh_frame and .debug_line have an empty
name, which appear in .symtab in the presence of RISC-V style linker
relaxation and will not be discarded by ld/objcopy --discard-locals
(-X).

In contrast, GNU assembler's riscv port assigns a fake name ".L0 " (with
a trailing space) to these symbols so that will be discarded by
ld/objcopy --discard-locals.

This patch matches the GNU behavior. Since Clang's RISC-V targets pass
-X to ld, and GNU ld defaults to -X for RISC-V targets, these ".L0 "
symbols will be discarded after linking by default, as expected by
users.

The llvm-symbolizer special case for RISC-V `SF_FormatSpecific` symbols
https://reviews.llvm.org/D98669 needs to be adjusted.

Note: `"":` in assembly currently crashes.

Note: bolt tests used /usr/bin/clang before
llvmorg-19-init-9532-g59bfc3106874.
The revert llvmorg-19-init-9531-g28b55342e1a8 actually broke
bolt/test/RISCV/fake-label-no-entry.c

2024-04-26 08:30:27 -07:00

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