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-rw-r--r--lib/MC/ELFObjectWriter.cpp89
-rw-r--r--lib/MC/MCAssembler.cpp10
-rw-r--r--lib/MC/MCELFStreamer.cpp54
-rw-r--r--lib/MC/MCExpr.cpp11
-rw-r--r--lib/MC/MCSymbol.cpp12
5 files changed, 60 insertions, 116 deletions
diff --git a/lib/MC/ELFObjectWriter.cpp b/lib/MC/ELFObjectWriter.cpp
index e11d68e..18d8e74 100644
--- a/lib/MC/ELFObjectWriter.cpp
+++ b/lib/MC/ELFObjectWriter.cpp
@@ -504,31 +504,6 @@ static uint64_t SymbolValue(MCSymbolData &Data, const MCAsmLayout &Layout) {
return 0;
}
-static const MCSymbol &AliasedSymbol(const MCSymbol &Symbol) {
- const MCSymbol *S = &Symbol;
- while (S->isVariable()) {
- const MCExpr *Value = S->getVariableValue();
- MCExpr::ExprKind Kind = Value->getKind();
- switch (Kind) {
- case MCExpr::SymbolRef: {
- const MCSymbolRefExpr *Ref = static_cast<const MCSymbolRefExpr*>(Value);
- S = &Ref->getSymbol();
- break;
- }
- case MCExpr::Target: {
- const MCTargetExpr *TExp = static_cast<const MCTargetExpr*>(Value);
- MCValue Res;
- TExp->EvaluateAsRelocatableImpl(Res, NULL);
- S = &Res.getSymA()->getSymbol();
- break;
- }
- default:
- return *S;
- }
- }
- return *S;
-}
-
void ELFObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm) {
// The presence of symbol versions causes undefined symbols and
// versions declared with @@@ to be renamed.
@@ -536,7 +511,7 @@ void ELFObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm) {
for (MCAssembler::symbol_iterator it = Asm.symbol_begin(),
ie = Asm.symbol_end(); it != ie; ++it) {
const MCSymbol &Alias = it->getSymbol();
- const MCSymbol &Symbol = AliasedSymbol(Alias);
+ const MCSymbol &Symbol = Alias.AliasedSymbol();
MCSymbolData &SD = Asm.getSymbolData(Symbol);
// Not an alias.
@@ -572,7 +547,7 @@ void ELFObjectWriter::WriteSymbol(MCDataFragment *SymtabF,
const MCAsmLayout &Layout) {
MCSymbolData &OrigData = *MSD.SymbolData;
MCSymbolData &Data =
- Layout.getAssembler().getSymbolData(AliasedSymbol(OrigData.getSymbol()));
+ Layout.getAssembler().getSymbolData(OrigData.getSymbol().AliasedSymbol());
bool IsReserved = Data.isCommon() || Data.getSymbol().isAbsolute() ||
Data.getSymbol().isVariable();
@@ -673,28 +648,24 @@ const MCSymbol *ELFObjectWriter::SymbolToReloc(const MCAssembler &Asm,
const MCValue &Target,
const MCFragment &F) const {
const MCSymbol &Symbol = Target.getSymA()->getSymbol();
- const MCSymbol &ASymbol = AliasedSymbol(Symbol);
- const MCSymbol *RenamedP = Renames.lookup(&Symbol);
-
- if (!RenamedP) {
- if (Target.getSymA()->getKind() == MCSymbolRefExpr::VK_None ||
- Asm.getSymbolData(Symbol).getFlags() & ELF_Other_Weakref)
- RenamedP = &ASymbol;
- else
- RenamedP = &Symbol;
+ const MCSymbol &ASymbol = Symbol.AliasedSymbol();
+ const MCSymbol *Renamed = Renames.lookup(&Symbol);
+ const MCSymbolData &SD = Asm.getSymbolData(Symbol);
+
+ if (ASymbol.isUndefined()) {
+ if (Renamed)
+ return Renamed;
+ return &ASymbol;
}
- const MCSymbol &Renamed = *RenamedP;
-
- MCSymbolData &SD = Asm.getSymbolData(Symbol);
-
- if (Symbol.isUndefined())
- return &Renamed;
- if (SD.isExternal())
- return &Renamed;
+ if (SD.isExternal()) {
+ if (Renamed)
+ return Renamed;
+ return &Symbol;
+ }
const MCSectionELF &Section =
- static_cast<const MCSectionELF&>(Symbol.getSection());
+ static_cast<const MCSectionELF&>(ASymbol.getSection());
if (Section.getKind().isBSS())
return NULL;
@@ -706,13 +677,18 @@ const MCSymbol *ELFObjectWriter::SymbolToReloc(const MCAssembler &Asm,
if (&Sec2 != &Section &&
(Kind == MCSymbolRefExpr::VK_PLT ||
Kind == MCSymbolRefExpr::VK_GOTPCREL ||
- Kind == MCSymbolRefExpr::VK_GOTOFF))
- return &Renamed;
+ Kind == MCSymbolRefExpr::VK_GOTOFF)) {
+ if (Renamed)
+ return Renamed;
+ return &Symbol;
+ }
if (Section.getFlags() & MCSectionELF::SHF_MERGE) {
- if (Target.getConstant() != 0)
- return &Renamed;
- return NULL;
+ if (Target.getConstant() == 0)
+ return NULL;
+ if (Renamed)
+ return Renamed;
+ return &Symbol;
}
return NULL;
@@ -742,7 +718,7 @@ static bool isInSymtab(const MCAssembler &Asm, const MCSymbolData &Data,
if (Symbol.getName() == "_GLOBAL_OFFSET_TABLE_")
return true;
- const MCSymbol &A = AliasedSymbol(Symbol);
+ const MCSymbol &A = Symbol.AliasedSymbol();
if (!A.isVariable() && A.isUndefined() && !Data.isCommon())
return false;
@@ -761,7 +737,7 @@ static bool isLocal(const MCSymbolData &Data, bool isSignature,
return false;
const MCSymbol &Symbol = Data.getSymbol();
- const MCSymbol &RefSymbol = AliasedSymbol(Symbol);
+ const MCSymbol &RefSymbol = Symbol.AliasedSymbol();
if (RefSymbol.isUndefined() && !RefSymbol.isVariable()) {
if (isSignature && !isUsedInReloc)
@@ -830,7 +806,7 @@ void ELFObjectWriter::ComputeSymbolTable(MCAssembler &Asm,
ELFSymbolData MSD;
MSD.SymbolData = it;
- const MCSymbol &RefSymbol = AliasedSymbol(Symbol);
+ const MCSymbol &RefSymbol = Symbol.AliasedSymbol();
// Undefined symbols are global, but this is the first place we
// are able to set it.
@@ -1104,13 +1080,13 @@ bool ELFObjectWriter::IsFixupFullyResolved(const MCAssembler &Asm,
const MCSection *SectionA = 0;
const MCSymbol *SymbolA = 0;
if (const MCSymbolRefExpr *A = Target.getSymA()) {
- SymbolA = &A->getSymbol();
+ SymbolA = &A->getSymbol().AliasedSymbol();
SectionA = &SymbolA->getSection();
}
const MCSection *SectionB = 0;
if (const MCSymbolRefExpr *B = Target.getSymB()) {
- SectionB = &B->getSymbol().getSection();
+ SectionB = &B->getSymbol().AliasedSymbol().getSection();
}
if (!BaseSection)
@@ -1413,6 +1389,7 @@ void X86ELFObjectWriter::RecordRelocation(const MCAssembler &Asm,
int Index = 0;
int64_t Value = Target.getConstant();
const MCSymbol &Symbol = Target.getSymA()->getSymbol();
+ const MCSymbol &ASymbol = Symbol.AliasedSymbol();
const MCSymbol *RelocSymbol = SymbolToReloc(Asm, Target, *Fragment);
bool IsPCRel = isFixupKindX86PCRel(Fixup.getKind());
@@ -1432,7 +1409,7 @@ void X86ELFObjectWriter::RecordRelocation(const MCAssembler &Asm,
}
if (!RelocSymbol) {
- MCSymbolData &SD = Asm.getSymbolData(Symbol);
+ MCSymbolData &SD = Asm.getSymbolData(ASymbol);
MCFragment *F = SD.getFragment();
Index = F->getParent()->getOrdinal();
diff --git a/lib/MC/MCAssembler.cpp b/lib/MC/MCAssembler.cpp
index 8e87d5b..c80dc3c 100644
--- a/lib/MC/MCAssembler.cpp
+++ b/lib/MC/MCAssembler.cpp
@@ -285,14 +285,16 @@ bool MCAssembler::EvaluateFixup(const MCObjectWriter &Writer,
Fixup.getKind()).Flags & MCFixupKindInfo::FKF_IsPCRel;
bool IsResolved = true;
if (const MCSymbolRefExpr *A = Target.getSymA()) {
- if (A->getSymbol().isDefined())
- Value += Layout.getSymbolAddress(&getSymbolData(A->getSymbol()));
+ const MCSymbol &Sym = A->getSymbol().AliasedSymbol();
+ if (Sym.isDefined())
+ Value += Layout.getSymbolAddress(&getSymbolData(Sym));
else
IsResolved = false;
}
if (const MCSymbolRefExpr *B = Target.getSymB()) {
- if (B->getSymbol().isDefined())
- Value -= Layout.getSymbolAddress(&getSymbolData(B->getSymbol()));
+ const MCSymbol &Sym = B->getSymbol().AliasedSymbol();
+ if (Sym.isDefined())
+ Value -= Layout.getSymbolAddress(&getSymbolData(Sym));
else
IsResolved = false;
}
diff --git a/lib/MC/MCELFStreamer.cpp b/lib/MC/MCELFStreamer.cpp
index a2d94f5..157c0c0 100644
--- a/lib/MC/MCELFStreamer.cpp
+++ b/lib/MC/MCELFStreamer.cpp
@@ -240,49 +240,6 @@ void MCELFStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
Symbol->setVariableValue(AddValueSymbols(Value));
}
-// This is a hack. To be able to implement weakrefs the writer has to be able
-// to distinguish
-// .weakref foo, bar
-// .long foo
-// from
-// .weakref foo, bar
-// .long bar
-// since the first case should produce a weak undefined reference and the second
-// one a strong one.
-// If we created foo as a regular alias pointing to bar (foo = bar), then
-// MCExpr::EvaluateAsRelocatable would recurse on foo and the writer would
-// never see it used in a relocation.
-// What we do is create a MCTargetExpr that when evaluated produces a symbol
-// ref to a temporary symbol. This temporary symbol in turn is a variable
-// that equals the original symbol (tmp = bar). With this hack the writer
-// gets a relocation with tmp and can correctly implement weak references.
-
-namespace {
-class WeakRefExpr : public MCTargetExpr {
-private:
- const MCSymbolRefExpr *Alias;
-
- explicit WeakRefExpr(const MCSymbolRefExpr *Alias_)
- : MCTargetExpr(), Alias(Alias_) {}
-
-public:
- virtual void PrintImpl(raw_ostream &OS) const {
- llvm_unreachable("Unimplemented");
- }
-
- virtual bool EvaluateAsRelocatableImpl(MCValue &Res,
- const MCAsmLayout *Layout) const {
- Res = MCValue::get(Alias, 0, 0);
- return true;
- }
-
- static const WeakRefExpr *Create(const MCSymbol *Alias, MCContext &Ctx) {
- const MCSymbolRefExpr *A = MCSymbolRefExpr::Create(Alias, Ctx);
- return new (Ctx) WeakRefExpr(A);
- }
-};
-} // end anonymous namespace
-
void MCELFStreamer::SwitchSection(const MCSection *Section) {
const MCSymbol *Grp = static_cast<const MCSectionELF *>(Section)->getGroup();
if (Grp)
@@ -294,16 +251,7 @@ void MCELFStreamer::EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) {
getAssembler().getOrCreateSymbolData(*Symbol);
MCSymbolData &AliasSD = getAssembler().getOrCreateSymbolData(*Alias);
AliasSD.setFlags(AliasSD.getFlags() | ELF_Other_Weakref);
-
- // Create the alias that actually points to Symbol
- const MCSymbolRefExpr *SymRef = MCSymbolRefExpr::Create(Symbol, getContext());
- MCSymbol *RealAlias = getContext().CreateTempSymbol();
- RealAlias->setVariableValue(SymRef);
-
- MCSymbolData &RealAliasSD = getAssembler().getOrCreateSymbolData(*RealAlias);
- RealAliasSD.setFlags(RealAliasSD.getFlags() | ELF_Other_Weakref);
-
- const MCExpr *Value = WeakRefExpr::Create(RealAlias, getContext());
+ const MCExpr *Value = MCSymbolRefExpr::Create(Symbol, getContext());
Alias->setVariableValue(Value);
}
diff --git a/lib/MC/MCExpr.cpp b/lib/MC/MCExpr.cpp
index b1617ec..eea736e 100644
--- a/lib/MC/MCExpr.cpp
+++ b/lib/MC/MCExpr.cpp
@@ -336,9 +336,14 @@ bool MCExpr::EvaluateAsRelocatableImpl(MCValue &Res,
const MCSymbol &Sym = SRE->getSymbol();
// Evaluate recursively if this is a variable.
- if (Sym.isVariable() && SRE->getKind() == MCSymbolRefExpr::VK_None)
- return Sym.getVariableValue()->EvaluateAsRelocatableImpl(Res, Layout,
- true);
+ if (Sym.isVariable() && SRE->getKind() == MCSymbolRefExpr::VK_None) {
+ bool Ret = Sym.getVariableValue()->EvaluateAsRelocatableImpl(Res, Layout,
+ true);
+ // If we failed to simplify this to a constant, let the target
+ // handle it.
+ if (Ret && !Res.getSymA() && !Res.getSymB())
+ return true;
+ }
Res = MCValue::get(SRE, 0, 0);
return true;
diff --git a/lib/MC/MCSymbol.cpp b/lib/MC/MCSymbol.cpp
index ebd3144..1c71f26 100644
--- a/lib/MC/MCSymbol.cpp
+++ b/lib/MC/MCSymbol.cpp
@@ -39,6 +39,18 @@ static bool NameNeedsQuoting(StringRef Str) {
return false;
}
+const MCSymbol &MCSymbol::AliasedSymbol() const {
+ const MCSymbol *S = this;
+ while (S->isVariable()) {
+ const MCExpr *Value = S->getVariableValue();
+ if (Value->getKind() != MCExpr::SymbolRef)
+ return *S;
+ const MCSymbolRefExpr *Ref = static_cast<const MCSymbolRefExpr*>(Value);
+ S = &Ref->getSymbol();
+ }
+ return *S;
+}
+
void MCSymbol::setVariableValue(const MCExpr *Value) {
assert(!IsUsed && "Cannot set a variable that has already been used.");
assert(Value && "Invalid variable value!");
generated by cgit v1.1 at 2024-09-28 14:35:37 +0000