A question of Go linker source code

fumeboy · May 1, 2023, 1:47pm

In the source code of the Go linker (cmd/link/internal/ld/lib.go), the function “loadlib” loads libraries and parses the object files of each library.

However, I have noticed that there are two strange duplicated loops here, and after reading the relevant code, it seems that the first loop can be removed.

github.com

golang/go/blob/069f9fb20548e904cb94f165f4cbf716a0fc108e/src/cmd/link/internal/ld/lib.go#L537


      
          		log.Fatalf("invalid -strictdups flag value %d", *FlagStrictDups)
          	}
          	elfsetstring1 := func(str string, off int) { elfsetstring(ctxt, 0, str, off) }
          	ctxt.loader = loader.NewLoader(flags, elfsetstring1, &ctxt.ErrorReporter.ErrorReporter)
          	ctxt.ErrorReporter.SymName = func(s loader.Sym) string {
          		return ctxt.loader.SymName(s)
          	}
          
          
	// ctxt.Library grows during the loop, so not a range loop.
          	i := 0
          	for ; i < len(ctxt.Library); i++ {
          		lib := ctxt.Library[i]
          		if lib.Shlib == "" {
          			if ctxt.Debugvlog > 1 {
          				ctxt.Logf("autolib: %s (from %s)\n", lib.File, lib.Objref)
          			}
          			loadobjfile(ctxt, lib)
          		}
          	}
          
          
	// load internal packages, if not already

As a Gopher, I would appreciate it if someone familiar with this part could help clarify this issue.