[lld] r329092 - Make fetchIfLazy only fetch an object file. NFC.

[Chandler Carruth via llvm-commits]

On Tue, Apr 3, 2018 at 11:04 AM Rui Ueyama via llvm-commits <
llvm-commits at lists.llvm.org> wrote:

> Author: ruiu
> Date: Tue Apr  3 11:01:18 2018
> New Revision: 329092
>
> URL: http://llvm.org/viewvc/llvm-project?rev=329092&view=rev
> Log:
> Make fetchIfLazy only fetch an object file. NFC.
>
> Previously, fetchIfLazy did more than the name says. Now, setting
> to UsedInRegularObj is moved to another function.
>
> Modified:
>     lld/trunk/ELF/Driver.cpp
>     lld/trunk/ELF/SymbolTable.cpp
>     lld/trunk/ELF/SymbolTable.h
>
> Modified: lld/trunk/ELF/Driver.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Driver.cpp?rev=329092&r1=329091&r2=329092&view=diff
>
> ==============================================================================
> --- lld/trunk/ELF/Driver.cpp (original)
> +++ lld/trunk/ELF/Driver.cpp Tue Apr  3 11:01:18 2018
> @@ -1017,6 +1017,20 @@ static void excludeLibs(opt::InputArgLis
>              Sym->VersionId = VER_NDX_LOCAL;
>  }
>
> +// Force Sym to be entered in the output. Used for -u or equivalent.
> +template <class ELFT> static void handleUndefined(StringRef Name) {
> +  Symbol *Sym = Symtab->find(Name);
> +  if (!Sym)
> +    return;
> +
> +  // Since symbol S may not be used inside the program, LTO may
> +  // eliminate it. Mark the symbol as "used" to prevent it.
> +  Sym->IsUsedInRegularObj = true;
> +
> +  if (Sym->isLazy())
> +    Symtab->fetchLazy<ELFT>(Sym);
>

Because this template is only defined in the other .cpp file, we can't
actually instantiate it here. As a consequence, I'm seeing link failures of
lld after this commit.


> +}
> +
>  // Do actual linking. Note that when this function is called,
>  // all linker scripts have already been parsed.
>  template <class ELFT> void LinkerDriver::link(opt::InputArgList &Args) {
> @@ -1081,16 +1095,12 @@ template <class ELFT> void LinkerDriver:
>
>    // Handle the `--undefined <sym>` options.
>    for (StringRef S : Config->Undefined)
> -    if (Symbol *Sym = Symtab->find(S))
> -      if (InputFile *F = Symtab->fetchIfLazy(Sym))
> -        Symtab->addFile<ELFT>(F);
> +    handleUndefined<ELFT>(S);
>
>    // If an entry symbol is in a static archive, pull out that file now
>    // to complete the symbol table. After this, no new names except a
>    // few linker-synthesized ones will be added to the symbol table.
> -  if (Symbol *Sym = Symtab->find(Config->Entry))
> -    if (InputFile *F = Symtab->fetchIfLazy(Sym))
> -      Symtab->addFile<ELFT>(F);
> +  handleUndefined<ELFT>(Config->Entry);
>
>    // Return if there were name resolution errors.
>    if (errorCount())
>
> Modified: lld/trunk/ELF/SymbolTable.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/SymbolTable.cpp?rev=329092&r1=329091&r2=329092&view=diff
>
> ==============================================================================
> --- lld/trunk/ELF/SymbolTable.cpp (original)
> +++ lld/trunk/ELF/SymbolTable.cpp Tue Apr  3 11:01:18 2018
> @@ -314,8 +314,8 @@ Symbol *SymbolTable::addUndefined(String
>      // Symbols.h for the details.
>      if (Binding == STB_WEAK)
>        S->Type = Type;
> -    else if (InputFile *F = Symtab->fetchIfLazy(S))
> -      addFile<ELFT>(F);
> +    else
> +      fetchLazy<ELFT>(S);
>    }
>    return S;
>  }
> @@ -574,15 +574,16 @@ void SymbolTable::addLazyObject(StringRe
>      addFile<ELFT>(F);
>  }
>
> -InputFile *SymbolTable::fetchIfLazy(Symbol *Sym) {
> -  // Mark the symbol not to be eliminated by LTO
> -  // even if it is a bitcode symbol.
> -  Sym->IsUsedInRegularObj = true;
> -  if (LazyArchive *L = dyn_cast<LazyArchive>(Sym))
> -    return L->fetch();
> -  if (LazyObject *L = dyn_cast<LazyObject>(Sym))
> -    return cast<LazyObjFile>(L->File)->fetch();
> -  return nullptr;
> +template <class ELFT> void SymbolTable::fetchLazy(Symbol *Sym) {
> +  if (auto *S = dyn_cast<LazyArchive>(Sym)) {
> +    if (InputFile *File = S->fetch())
> +      addFile<ELFT>(File);
> +    return;
> +  }
> +
> +  auto *S = cast<LazyObject>(Sym);
> +  if (InputFile *File = cast<LazyObjFile>(S->File)->fetch())
> +    addFile<ELFT>(File);
>  }
>
>  // Initialize DemangledSyms with a map from demangled symbols to symbol
>
> Modified: lld/trunk/ELF/SymbolTable.h
> URL:
> http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/SymbolTable.h?rev=329092&r1=329091&r2=329092&view=diff
>
> ==============================================================================
> --- lld/trunk/ELF/SymbolTable.h (original)
> +++ lld/trunk/ELF/SymbolTable.h Tue Apr  3 11:01:18 2018
> @@ -77,7 +77,7 @@ public:
>                                     uint8_t Visibility, bool
> CanOmitFromDynSym,
>                                     InputFile *File);
>
> -  InputFile *fetchIfLazy(Symbol *Sym);
> +  template <class ELFT> void fetchLazy(Symbol *Sym);
>
>    void scanVersionScript();
>
>
>
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