Fix pr19645.
The fix itself is fairly simple: move getAccessVariant to MCValue so that we
replace the old weak expression evaluation with the far more general
EvaluateAsRelocatable.
This then requires that EvaluateAsRelocatable stop when it finds a non
trivial reference kind. And that in turn requires the ELF writer to look
harder for weak references.
Last but not least, this found a case where we were being bug by bug
compatible with gas and accepting an invalid input. I reported pr19647
to track it.
llvm-svn: 207920
diff --git a/llvm/lib/MC/ELFObjectWriter.cpp b/llvm/lib/MC/ELFObjectWriter.cpp
index 3bce121..0a54627 100644
--- a/llvm/lib/MC/ELFObjectWriter.cpp
+++ b/llvm/lib/MC/ELFObjectWriter.cpp
@@ -787,6 +787,25 @@
return false;
}
+static const MCSymbol *getWeakRef(const MCSymbolRefExpr &Ref) {
+ const MCSymbol &Sym = Ref.getSymbol();
+
+ if (Ref.getKind() == MCSymbolRefExpr::VK_WEAKREF)
+ return &Sym;
+
+ if (!Sym.isVariable())
+ return nullptr;
+
+ const MCExpr *Expr = Sym.getVariableValue();
+ const auto *Inner = dyn_cast<MCSymbolRefExpr>(Expr);
+ if (!Inner)
+ return nullptr;
+
+ if (Inner->getKind() == MCSymbolRefExpr::VK_WEAKREF)
+ return &Inner->getSymbol();
+ return nullptr;
+}
+
void ELFObjectWriter::RecordRelocation(const MCAssembler &Asm,
const MCAsmLayout &Layout,
const MCFragment *Fragment,
@@ -872,8 +891,8 @@
if (const MCSymbol *R = Renames.lookup(SymA))
SymA = R;
- if (RefA->getKind() == MCSymbolRefExpr::VK_WEAKREF)
- WeakrefUsedInReloc.insert(SymA);
+ if (const MCSymbol *WeakRef = getWeakRef(*RefA))
+ WeakrefUsedInReloc.insert(WeakRef);
else
UsedInReloc.insert(SymA);
}