[lld] [lld][WebAssembly] Add RUNTIME_PATH support to wasm-ld (PR #129050)

[Sam Clegg via llvm-commits]

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@@ -289,6 +291,7 @@ def: Flag<["-"], "t">, Alias<trace>, HelpText<"Alias for --trace">;
 def: JoinedOrSeparate<["-"], "y">, Alias<trace_symbol>, HelpText<"Alias for --trace-symbol">;
 def: JoinedOrSeparate<["-"], "u">, Alias<undefined>;
 def: Flag<["-"], "V">, Alias<v>, HelpText<"Alias for -v">;
+def: JoinedOrSeparate<["-"], "R">, Alias<rpath>, HelpText<"Alias for --rpath">;
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sbc100 wrote:

Where is `-R` coming from?   I don't see this in GNU ld (in fact, it looks like `-R` means something different there).

```
       -R filename
       --just-symbols=filename
           Read symbol names and their addresses from filename, but do not relocate it or include it  in  the  output.   This  allows  your
           output  file to refer symbolically to absolute locations of memory defined in other programs.  You may use this option more than
           once.

           For compatibility with other ELF linkers, if the -R option is followed by a directory name, rather  than  a  file  name,  it  is
           treated as the -rpath option.
```

I do see -R in `lld/ELF/Options.td`... but I don't see any testing for this alias, or any reason to copy it.

Digging a little deeper I see it was added in 575ad8c2e13d6099f67d9d5e816fad8968c6e900 by davide at freebsd.org so perhaps this flags from the BSD linker?   Anyway, lets not copy it unless we have to.



https://github.com/llvm/llvm-project/pull/129050