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

[Vitaly Buka via Phabricator via llvm-commits]

vitalybuka updated this revision to Diff 137810.
vitalybuka added a comment.

clang-format


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 +1,17 @@
+; 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 ".local _start1"
+
+; CHECK-DAG: t _start1
+; CHECK-DAG: U _start2
+; CHECK-DAG: t foo@@SOME_VERSION1
+; CHECK-DAG: t foo at SOME_VERSION2
Index: llvm/lib/Object/RecordStreamer.cpp
===================================================================
--- llvm/lib/Object/RecordStreamer.cpp
+++ llvm/lib/Object/RecordStreamer.cpp
@@ -143,9 +143,40 @@
 
 void RecordStreamer::emitELFSymverDirective(StringRef AliasName,
                                             const MCSymbol *Aliasee) {
+  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
+    bool IsDefined = false;
+    // First check if the aliasee was recorded in the asm.
+    switch (getSymbolState(Aliasee)) {
+    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;
+    }
+    if (!IsDefined) {
+      // If we don't have it in assembly, then check if the aliasee was
+      // defined in the IR.
+      const GlobalValue *GV = M.getNamedValue(Aliasee->getName());
+      if (!GV) {
+        auto MI = MangledNameMap.find(Aliasee->getName());
+        if (MI != MangledNameMap.end())
+          GV = MI->second;
+      }
+      IsDefined = GV && GV->isDefinitionExact();
+    }
+    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 @@.
   const MCExpr *Value = MCSymbolRefExpr::create(Aliasee, getContext());
   EmitAssignment(Alias, Value);
   SymverAliasMap[Aliasee].push_back(Alias);


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