X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FMC%2FMCAssembler.cpp;h=a6aa5da2421a5be2969b62641098e48046b22b85;hb=6c0e1e0fa658f4e7466c6787aedce992ece2db55;hp=2cee2b8a475cc9b92bdccbbf9b8c50e1cd5a0696;hpb=4266ae806798f1e8982a53bb9babe1e508adfc68;p=oota-llvm.git diff --git a/lib/MC/MCAssembler.cpp b/lib/MC/MCAssembler.cpp index 2cee2b8a475..a6aa5da2421 100644 --- a/lib/MC/MCAssembler.cpp +++ b/lib/MC/MCAssembler.cpp @@ -7,7 +7,6 @@ // //===----------------------------------------------------------------------===// -#define DEBUG_TYPE "assembler" #include "llvm/MC/MCAssembler.h" #include "llvm/ADT/Statistic.h" #include "llvm/ADT/StringExtras.h" @@ -28,9 +27,12 @@ #include "llvm/Support/LEB128.h" #include "llvm/Support/TargetRegistry.h" #include "llvm/Support/raw_ostream.h" - +#include "llvm/MC/MCSectionELF.h" +#include using namespace llvm; +#define DEBUG_TYPE "assembler" + namespace { namespace stats { STATISTIC(EmittedFragments, "Number of emitted assembler fragments - total"); @@ -116,36 +118,89 @@ uint64_t MCAsmLayout::getFragmentOffset(const MCFragment *F) const { return F->Offset; } -uint64_t MCAsmLayout::getSymbolOffset(const MCSymbolData *SD) const { +// Simple getSymbolOffset helper for the non-varibale case. +static bool getLabelOffset(const MCAsmLayout &Layout, const MCSymbolData &SD, + bool ReportError, uint64_t &Val) { + if (!SD.getFragment()) { + if (ReportError) + report_fatal_error("unable to evaluate offset to undefined symbol '" + + SD.getSymbol().getName() + "'"); + return false; + } + Val = Layout.getFragmentOffset(SD.getFragment()) + SD.getOffset(); + return true; +} + +static bool getSymbolOffsetImpl(const MCAsmLayout &Layout, + const MCSymbolData *SD, bool ReportError, + uint64_t &Val) { const MCSymbol &S = SD->getSymbol(); - // If this is a variable, then recursively evaluate now. - if (S.isVariable()) { - MCValue Target; - if (!S.getVariableValue()->EvaluateAsRelocatable(Target, this)) - report_fatal_error("unable to evaluate offset for variable '" + - S.getName() + "'"); + if (!S.isVariable()) + return getLabelOffset(Layout, *SD, ReportError, Val); - // Verify that any used symbols are defined. - if (Target.getSymA() && Target.getSymA()->getSymbol().isUndefined()) - report_fatal_error("unable to evaluate offset to undefined symbol '" + - Target.getSymA()->getSymbol().getName() + "'"); - if (Target.getSymB() && Target.getSymB()->getSymbol().isUndefined()) - report_fatal_error("unable to evaluate offset to undefined symbol '" + - Target.getSymB()->getSymbol().getName() + "'"); - - uint64_t Offset = Target.getConstant(); - if (Target.getSymA()) - Offset += getSymbolOffset(&Assembler.getSymbolData( - Target.getSymA()->getSymbol())); - if (Target.getSymB()) - Offset -= getSymbolOffset(&Assembler.getSymbolData( - Target.getSymB()->getSymbol())); - return Offset; + // If SD is a variable, evaluate it. + MCValue Target; + if (!S.getVariableValue()->EvaluateAsValue(Target, &Layout, nullptr)) + report_fatal_error("unable to evaluate offset for variable '" + + S.getName() + "'"); + + uint64_t Offset = Target.getConstant(); + + const MCAssembler &Asm = Layout.getAssembler(); + + const MCSymbolRefExpr *A = Target.getSymA(); + if (A) { + uint64_t ValA; + if (!getLabelOffset(Layout, Asm.getSymbolData(A->getSymbol()), ReportError, + ValA)) + return false; + Offset += ValA; + } + + const MCSymbolRefExpr *B = Target.getSymB(); + if (B) { + uint64_t ValB; + if (!getLabelOffset(Layout, Asm.getSymbolData(B->getSymbol()), ReportError, + ValB)) + return false; + Offset -= ValB; } - assert(SD->getFragment() && "Invalid getOffset() on undefined symbol!"); - return getFragmentOffset(SD->getFragment()) + SD->getOffset(); + Val = Offset; + return true; +} + +bool MCAsmLayout::getSymbolOffset(const MCSymbolData *SD, uint64_t &Val) const { + return getSymbolOffsetImpl(*this, SD, false, Val); +} + +uint64_t MCAsmLayout::getSymbolOffset(const MCSymbolData *SD) const { + uint64_t Val; + getSymbolOffsetImpl(*this, SD, true, Val); + return Val; +} + +const MCSymbol *MCAsmLayout::getBaseSymbol(const MCSymbol &Symbol) const { + if (!Symbol.isVariable()) + return &Symbol; + + const MCExpr *Expr = Symbol.getVariableValue(); + MCValue Value; + if (!Expr->EvaluateAsValue(Value, this, nullptr)) + llvm_unreachable("Invalid Expression"); + + const MCSymbolRefExpr *RefB = Value.getSymB(); + if (RefB) + Assembler.getContext().FatalError( + SMLoc(), Twine("symbol '") + RefB->getSymbol().getName() + + "' could not be evaluated in a subtraction expression"); + + const MCSymbolRefExpr *A = Value.getSymA(); + if (!A) + return nullptr; + + return &A->getSymbol(); } uint64_t MCAsmLayout::getSectionAddressSize(const MCSectionData *SD) const { @@ -322,6 +377,31 @@ void MCAssembler::reset() { getLOHContainer().reset(); } +bool MCAssembler::isThumbFunc(const MCSymbol *Symbol) const { + if (ThumbFuncs.count(Symbol)) + return true; + + if (!Symbol->isVariable()) + return false; + + // FIXME: It looks like gas supports some cases of the form "foo + 2". It + // is not clear if that is a bug or a feature. + const MCExpr *Expr = Symbol->getVariableValue(); + const MCSymbolRefExpr *Ref = dyn_cast(Expr); + if (!Ref) + return false; + + if (Ref->getKind() != MCSymbolRefExpr::VK_None) + return false; + + const MCSymbol &Sym = Ref->getSymbol(); + if (!isThumbFunc(&Sym)) + return false; + + ThumbFuncs.insert(Symbol); // Cache it. + return true; +} + bool MCAssembler::isSymbolLinkerVisible(const MCSymbol &Symbol) const { // Non-temporary labels should always be visible to the linker. if (!Symbol.isTemporary()) @@ -354,12 +434,28 @@ const MCSymbolData *MCAssembler::getAtom(const MCSymbolData *SD) const { return SD->getFragment()->getAtom(); } +// Try to fully compute Expr to an absolute value and if that fails produce +// a relocatable expr. +// FIXME: Should this be the behavior of EvaluateAsRelocatable itself? +static bool evaluate(const MCExpr &Expr, const MCAsmLayout &Layout, + const MCFixup &Fixup, MCValue &Target) { + if (Expr.EvaluateAsValue(Target, &Layout, &Fixup)) { + if (Target.isAbsolute()) + return true; + } + return Expr.EvaluateAsRelocatable(Target, &Layout, &Fixup); +} + bool MCAssembler::evaluateFixup(const MCAsmLayout &Layout, const MCFixup &Fixup, const MCFragment *DF, MCValue &Target, uint64_t &Value) const { ++stats::evaluateFixup; - if (!Fixup.getValue()->EvaluateAsRelocatable(Target, &Layout)) + // FIXME: This code has some duplication with RecordRelocation. We should + // probably merge the two into a single callback that tries to evaluate a + // fixup and records a relocation if one is needed. + const MCExpr *Expr = Fixup.getValue(); + if (!evaluate(*Expr, Layout, Fixup, Target)) getContext().FatalError(Fixup.getLoc(), "expected relocatable expression"); bool IsPCRel = Backend.getFixupKindInfo( @@ -703,8 +799,13 @@ void MCAssembler::writeSectionData(const MCSectionData *SD, assert(DF.fixup_begin() == DF.fixup_end() && "Cannot have fixups in virtual section!"); for (unsigned i = 0, e = DF.getContents().size(); i != e; ++i) - assert(DF.getContents()[i] == 0 && - "Invalid data value for virtual section!"); + if (DF.getContents()[i]) { + if (auto *ELFSec = dyn_cast(&SD->getSection())) + report_fatal_error("non-zero initializer found in section '" + + ELFSec->getSectionName() + "'"); + else + report_fatal_error("non-zero initializer found in virtual section"); + } break; } case MCFragment::FT_Align: @@ -893,11 +994,8 @@ bool MCAssembler::relaxInstruction(MCAsmLayout &Layout, } bool MCAssembler::relaxLEB(MCAsmLayout &Layout, MCLEBFragment &LF) { - int64_t Value = 0; uint64_t OldSize = LF.getContents().size(); - bool IsAbs = LF.getValue().EvaluateAsAbsolute(Value, Layout); - (void)IsAbs; - assert(IsAbs); + int64_t Value = LF.getValue().evaluateKnownAbsolute(Layout); SmallString<8> &Data = LF.getContents(); Data.clear(); raw_svector_ostream OSE(Data); @@ -912,11 +1010,8 @@ bool MCAssembler::relaxLEB(MCAsmLayout &Layout, MCLEBFragment &LF) { bool MCAssembler::relaxDwarfLineAddr(MCAsmLayout &Layout, MCDwarfLineAddrFragment &DF) { MCContext &Context = Layout.getAssembler().getContext(); - int64_t AddrDelta = 0; uint64_t OldSize = DF.getContents().size(); - bool IsAbs = DF.getAddrDelta().EvaluateAsAbsolute(AddrDelta, Layout); - (void)IsAbs; - assert(IsAbs); + int64_t AddrDelta = DF.getAddrDelta().evaluateKnownAbsolute(Layout); int64_t LineDelta; LineDelta = DF.getLineDelta(); SmallString<8> &Data = DF.getContents(); @@ -930,11 +1025,8 @@ bool MCAssembler::relaxDwarfLineAddr(MCAsmLayout &Layout, bool MCAssembler::relaxDwarfCallFrameFragment(MCAsmLayout &Layout, MCDwarfCallFrameFragment &DF) { MCContext &Context = Layout.getAssembler().getContext(); - int64_t AddrDelta = 0; uint64_t OldSize = DF.getContents().size(); - bool IsAbs = DF.getAddrDelta().EvaluateAsAbsolute(AddrDelta, Layout); - (void)IsAbs; - assert(IsAbs); + int64_t AddrDelta = DF.getAddrDelta().evaluateKnownAbsolute(Layout); SmallString<8> &Data = DF.getContents(); Data.clear(); raw_svector_ostream OSE(Data); @@ -1143,7 +1235,7 @@ void MCSectionData::dump() { OS << "]>"; } -void MCSymbolData::dump() { +void MCSymbolData::dump() const { raw_ostream &OS = llvm::errs(); OS << "