[PATCH] D44274: Object: Fix handling of @@@ in .symver directive

[Rafael Avila de Espindola via llvm-commits]

LGTM

Thanks,
Rafael

Vitaly Buka via Phabricator via llvm-commits
<llvm-commits at lists.llvm.org> writes:

> vitalybuka updated this revision to Diff 137861.
> vitalybuka added a comment.
>
> fix
>
>
> https://reviews.llvm.org/D44274
>
> Files:
>   llvm/lib/Object/RecordStreamer.cpp
>   llvm/test/LTO/X86/symver-asm3.ll
>
> Index: llvm/test/LTO/X86/symver-asm3.ll
> ===================================================================
> --- /dev/null
> +++ llvm/test/LTO/X86/symver-asm3.ll
> @@ -0,0 +1,21 @@
> +; Test special handling of @@@.
> +
> +; RUN: llvm-as < %s >%t1
> +; RUN: llvm-nm %t1 | FileCheck %s
> +
> +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
> +target triple = "x86_64-unknown-linux-gnu"
> +
> +module asm "_start1:"
> +module asm ".symver _start1, foo@@@SOME_VERSION1"
> +module asm ".symver _start2, foo@@@SOME_VERSION2"
> +module asm ".symver _start3, foo@@@SOME_VERSION3"
> +module asm "_start3:"
> +module asm ".local _start1"
> +module asm ".local _start3"
> +
> +; CHECK-DAG: t _start1
> +; CHECK-DAG: U _start2
> +; CHECK-DAG: t foo@@SOME_VERSION1
> +; CHECK-DAG: t foo at SOME_VERSION2
> +; CHECK-DAG: t foo@@SOME_VERSION3
> Index: llvm/lib/Object/RecordStreamer.cpp
> ===================================================================
> --- llvm/lib/Object/RecordStreamer.cpp
> +++ llvm/lib/Object/RecordStreamer.cpp
> @@ -149,6 +149,7 @@
>    for (auto &Symver : SymverAliasMap) {
>      const MCSymbol *Aliasee = Symver.first;
>      MCSymbolAttr Attr = MCSA_Invalid;
> +    bool IsDefined = false;
>  
>      // First check if the aliasee binding was recorded in the asm.
>      RecordStreamer::State state = getSymbolState(Aliasee);
> @@ -165,26 +166,53 @@
>        break;
>      }
>  
> -    // If we don't have a symbol attribute from assembly, then check if
> -    // the aliasee was defined in the IR.
> -    if (Attr == MCSA_Invalid) {
> -      const auto *GV = M.getNamedValue(Aliasee->getName());
> +    switch (state) {
> +    case RecordStreamer::Defined:
> +    case RecordStreamer::DefinedGlobal:
> +    case RecordStreamer::DefinedWeak:
> +      IsDefined = true;
> +      break;
> +    case RecordStreamer::NeverSeen:
> +    case RecordStreamer::Global:
> +    case RecordStreamer::Used:
> +    case RecordStreamer::UndefinedWeak:
> +      break;
> +    }
> +
> +    const GlobalValue *GV = nullptr;
> +    if (Attr == MCSA_Invalid || !IsDefined) {
> +      GV = M.getNamedValue(Aliasee->getName());
>        if (!GV) {
>          auto MI = MangledNameMap.find(Aliasee->getName());
>          if (MI != MangledNameMap.end())
>            GV = MI->second;
>        }
>        if (GV) {
> -        if (GV->hasExternalLinkage())
> -          Attr = MCSA_Global;
> -        else if (GV->hasLocalLinkage())
> -          Attr = MCSA_Local;
> -        else if (GV->isWeakForLinker())
> -          Attr = MCSA_Weak;
> +        // If we don't have a symbol attribute from assembly, then check if
> +        // the aliasee was defined in the IR.
> +        if (Attr == MCSA_Invalid) {
> +          if (GV->hasExternalLinkage())
> +            Attr = MCSA_Global;
> +          else if (GV->hasLocalLinkage())
> +            Attr = MCSA_Local;
> +          else if (GV->isWeakForLinker())
> +            Attr = MCSA_Weak;
> +        }
> +        IsDefined = IsDefined || !GV->isDeclarationForLinker();
>        }
>      }
> +
>      // Set the detected binding on each alias with this aliasee.
>      for (auto AliasName : Symver.second) {
> +      std::pair<StringRef, StringRef> Split = AliasName.split("@@@");
> +      SmallString<128> NewName;
> +      if (!Split.second.empty() && !Split.second.startswith("@")) {
> +        // Special processing for "@@@" according
> +        // https://sourceware.org/binutils/docs/as/Symver.html
> +        const char *Separator = IsDefined ? "@@" : "@";
> +        AliasName =
> +            (Split.first + Separator + Split.second).toStringRef(NewName);
> +      }
>        MCSymbol *Alias = getContext().getOrCreateSymbol(AliasName);
>        // TODO: Handle "@@@". Depending on SymbolAttribute value it needs to be
>        // converted into @ or @@.
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