[llvm] [llvm-nm] Introduce synthetic flag (PR #138232)

[Fangrui Song via llvm-commits]

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@@ -257,6 +257,11 @@ OPTIONS
 
  Do not filter special symbols from the output.
 
+.. option:: --synthetic
+ Include synthetic symbols in the output. Synthetic symbols are not present in
+ the original object file but are generated by the tool to represent relevant
+ runtime or linking information.
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MaskRay wrote:

Perhaps 

Include synthetic symbols in the output. Synthetic symbols are not present in the original object file. This currently includes symbols derived from PLT entries for ELF.

I find 
"are generated by the tool to represent relevant runtime or linking information." very vague and not very useful. The PLT detail seems important.

https://github.com/llvm/llvm-project/pull/138232