[PATCH] D53044: [ELF] Don't warn on undefined symbols if UnresolvedPolicy::Ignore is used

[Fangrui Song via Phabricator via llvm-commits]

MaskRay added inline comments.


================
Comment at: ELF/Symbols.cpp:280-288
     Warn(": unable to order shared symbol: ");
-  else if (D && !D->Section)
-    Warn(": unable to order absolute symbol: ");
-  else if (D && isa<OutputSection>(D->Section))
-    Warn(": unable to order synthetic symbol: ");
-  else if (D && !D->Section->Repl->Live)
-    Warn(": unable to order discarded symbol: ");
+  } else if (D) {
+    if (!D->Section)
+      Warn(": unable to order absolute symbol: ");
+    else if (isa<OutputSection>(D->Section))
+      Warn(": unable to order synthetic symbol: ");
+    else if (!D->Section->Repl->Live)
----------------
ruiu wrote:
> MaskRay wrote:
> > ruiu wrote:
> > > Please do not change this -- this code was written in the way it is to reduce indentation depth.
> > Should I use `if (Sym->isUndefined() && Config->UnresolvedSymbols != UnresolvedPolicy::Ignore)` then?
> > 
> > I actually find dispatching by `SymbolKind` first makes the code a bit easier to understand:
> > 
> > * Undefined
> > * Shared
> > * Others (Defined)
> > 
> > For the `Defined` case, fine-grained conditions are checked for absolute/syunthetic/discarded.
> > 
> > I lean to this style but if you have strong opinion on this, I can change it.
> Yeah, maybe you should write that `if` at the beginning of this function to exit early.
But that way:

```
  if (Sym->isUndefined() && Config->UnresolvedSymbols != UnresolvedPolicy::Ignore)
    Warn(": unable to order undefined symbol: ");
  else if (Sym->isShared())
    Warn(": unable to order undefined symbol: ");
  else if (Sym->isShared())
    Warn(": unable to order shared symbol: ");
////// Sym->isUndefined() is possible here
  else if (D && !D->Section)
    Warn(": unable to order absolute symbol: ");
  else if (D && isa<OutputSection>(D->Section))
    Warn(": unable to order synthetic symbol: ");
  else if (D && !D->Section->Repl->Live)
    Warn(": unable to order discarded symbol: ");
```

Will that cause a problem?


Repository:
  rLLD LLVM Linker

https://reviews.llvm.org/D53044