diff options
Diffstat (limited to 'lib/MC/MCExpr.cpp')
| -rw-r--r-- | lib/MC/MCExpr.cpp | 253 |
1 files changed, 181 insertions, 72 deletions
diff --git a/lib/MC/MCExpr.cpp b/lib/MC/MCExpr.cpp index eea736e..54d3743 100644 --- a/lib/MC/MCExpr.cpp +++ b/lib/MC/MCExpr.cpp @@ -14,7 +14,6 @@ #include "llvm/MC/MCAsmLayout.h" #include "llvm/MC/MCAssembler.h" #include "llvm/MC/MCContext.h" -#include "llvm/MC/MCObjectFormat.h" #include "llvm/MC/MCSymbol.h" #include "llvm/MC/MCValue.h" #include "llvm/Support/Debug.h" @@ -43,10 +42,6 @@ void MCExpr::print(raw_ostream &OS) const { // absolute names. bool UseParens = Sym.getName()[0] == '$'; - if (SRE.getKind() == MCSymbolRefExpr::VK_ARM_HI16 || - SRE.getKind() == MCSymbolRefExpr::VK_ARM_LO16) - OS << MCSymbolRefExpr::getVariantKindName(SRE.getKind()); - if (SRE.getKind() == MCSymbolRefExpr::VK_PPC_HA16 || SRE.getKind() == MCSymbolRefExpr::VK_PPC_LO16) { OS << MCSymbolRefExpr::getVariantKindName(SRE.getKind()); @@ -66,8 +61,6 @@ void MCExpr::print(raw_ostream &OS) const { SRE.getKind() == MCSymbolRefExpr::VK_ARM_GOTTPOFF) OS << MCSymbolRefExpr::getVariantKindName(SRE.getKind()); else if (SRE.getKind() != MCSymbolRefExpr::VK_None && - SRE.getKind() != MCSymbolRefExpr::VK_ARM_HI16 && - SRE.getKind() != MCSymbolRefExpr::VK_ARM_LO16 && SRE.getKind() != MCSymbolRefExpr::VK_PPC_HA16 && SRE.getKind() != MCSymbolRefExpr::VK_PPC_LO16) OS << '@' << MCSymbolRefExpr::getVariantKindName(SRE.getKind()); @@ -197,14 +190,12 @@ StringRef MCSymbolRefExpr::getVariantKindName(VariantKind Kind) { case VK_TPOFF: return "TPOFF"; case VK_DTPOFF: return "DTPOFF"; case VK_TLVP: return "TLVP"; - case VK_ARM_HI16: return ":upper16:"; - case VK_ARM_LO16: return ":lower16:"; case VK_ARM_PLT: return "(PLT)"; case VK_ARM_GOT: return "(GOT)"; case VK_ARM_GOTOFF: return "(GOTOFF)"; case VK_ARM_TPOFF: return "(tpoff)"; case VK_ARM_GOTTPOFF: return "(gottpoff)"; - case VK_ARM_TLSGD: return "(tldgd)"; + case VK_ARM_TLSGD: return "(tlsgd)"; case VK_PPC_TOC: return "toc"; case VK_PPC_HA16: return "ha16"; case VK_PPC_LO16: return "lo16"; @@ -215,19 +206,33 @@ MCSymbolRefExpr::VariantKind MCSymbolRefExpr::getVariantKindForName(StringRef Name) { return StringSwitch<VariantKind>(Name) .Case("GOT", VK_GOT) + .Case("got", VK_GOT) .Case("GOTOFF", VK_GOTOFF) + .Case("gotoff", VK_GOTOFF) .Case("GOTPCREL", VK_GOTPCREL) + .Case("gotpcrel", VK_GOTPCREL) .Case("GOTTPOFF", VK_GOTTPOFF) + .Case("gottpoff", VK_GOTTPOFF) .Case("INDNTPOFF", VK_INDNTPOFF) + .Case("indntpoff", VK_INDNTPOFF) .Case("NTPOFF", VK_NTPOFF) + .Case("ntpoff", VK_NTPOFF) .Case("GOTNTPOFF", VK_GOTNTPOFF) + .Case("gotntpoff", VK_GOTNTPOFF) .Case("PLT", VK_PLT) + .Case("plt", VK_PLT) .Case("TLSGD", VK_TLSGD) + .Case("tlsgd", VK_TLSGD) .Case("TLSLD", VK_TLSLD) + .Case("tlsld", VK_TLSLD) .Case("TLSLDM", VK_TLSLDM) + .Case("tlsldm", VK_TLSLDM) .Case("TPOFF", VK_TPOFF) + .Case("tpoff", VK_TPOFF) .Case("DTPOFF", VK_DTPOFF) + .Case("dtpoff", VK_DTPOFF) .Case("TLVP", VK_TLVP) + .Case("tlvp", VK_TLVP) .Default(VK_Invalid); } @@ -237,7 +242,28 @@ void MCTargetExpr::Anchor() {} /* *** */ -bool MCExpr::EvaluateAsAbsolute(int64_t &Res, const MCAsmLayout *Layout) const { +bool MCExpr::EvaluateAsAbsolute(int64_t &Res) const { + return EvaluateAsAbsolute(Res, 0, 0, 0); +} + +bool MCExpr::EvaluateAsAbsolute(int64_t &Res, + const MCAsmLayout &Layout) const { + return EvaluateAsAbsolute(Res, &Layout.getAssembler(), &Layout, 0); +} + +bool MCExpr::EvaluateAsAbsolute(int64_t &Res, + const MCAsmLayout &Layout, + const SectionAddrMap &Addrs) const { + return EvaluateAsAbsolute(Res, &Layout.getAssembler(), &Layout, &Addrs); +} + +bool MCExpr::EvaluateAsAbsolute(int64_t &Res, const MCAssembler &Asm) const { + return EvaluateAsAbsolute(Res, &Asm, 0, 0); +} + +bool MCExpr::EvaluateAsAbsolute(int64_t &Res, const MCAssembler *Asm, + const MCAsmLayout *Layout, + const SectionAddrMap *Addrs) const { MCValue Value; // Fast path constants. @@ -246,80 +272,158 @@ bool MCExpr::EvaluateAsAbsolute(int64_t &Res, const MCAsmLayout *Layout) const { return true; } - if (!EvaluateAsRelocatable(Value, Layout) || !Value.isAbsolute()) { - // EvaluateAsAbsolute is defined to return the "current value" of - // the expression if we are given a Layout object, even in cases - // when the value is not fixed. - if (Layout) { - Res = Value.getConstant(); - if (Value.getSymA()) { - Res += Layout->getSymbolAddress( - &Layout->getAssembler().getSymbolData(Value.getSymA()->getSymbol())); - } - if (Value.getSymB()) { - Res -= Layout->getSymbolAddress( - &Layout->getAssembler().getSymbolData(Value.getSymB()->getSymbol())); - } - } - return false; - } + // FIXME: The use if InSet = Addrs is a hack. Setting InSet causes us + // absolutize differences across sections and that is what the MachO writer + // uses Addrs for. + bool IsRelocatable = + EvaluateAsRelocatableImpl(Value, Asm, Layout, Addrs, /*InSet*/ Addrs); + // Record the current value. Res = Value.getConstant(); - return true; + + return IsRelocatable && Value.isAbsolute(); } -static bool EvaluateSymbolicAdd(const MCAsmLayout *Layout, bool InSet, +/// \brief Helper method for \see EvaluateSymbolAdd(). +static void AttemptToFoldSymbolOffsetDifference(const MCAssembler *Asm, + const MCAsmLayout *Layout, + const SectionAddrMap *Addrs, + bool InSet, + const MCSymbolRefExpr *&A, + const MCSymbolRefExpr *&B, + int64_t &Addend) { + if (!A || !B) + return; + + const MCSymbol &SA = A->getSymbol(); + const MCSymbol &SB = B->getSymbol(); + + if (SA.isUndefined() || SB.isUndefined()) + return; + + if (!Asm->getWriter().IsSymbolRefDifferenceFullyResolved(*Asm, A, B, InSet)) + return; + + MCSymbolData &AD = Asm->getSymbolData(SA); + MCSymbolData &BD = Asm->getSymbolData(SB); + + if (AD.getFragment() == BD.getFragment()) { + Addend += (AD.getOffset() - BD.getOffset()); + + // Clear the symbol expr pointers to indicate we have folded these + // operands. + A = B = 0; + return; + } + + if (!Layout) + return; + + const MCSectionData &SecA = *AD.getFragment()->getParent(); + const MCSectionData &SecB = *BD.getFragment()->getParent(); + + if ((&SecA != &SecB) && !Addrs) + return; + + // Eagerly evaluate. + Addend += (Layout->getSymbolOffset(&Asm->getSymbolData(A->getSymbol())) - + Layout->getSymbolOffset(&Asm->getSymbolData(B->getSymbol()))); + if (Addrs && (&SecA != &SecB)) + Addend += (Addrs->lookup(&SecA) - Addrs->lookup(&SecB)); + + // Clear the symbol expr pointers to indicate we have folded these + // operands. + A = B = 0; +} + +/// \brief Evaluate the result of an add between (conceptually) two MCValues. +/// +/// This routine conceptually attempts to construct an MCValue: +/// Result = (Result_A - Result_B + Result_Cst) +/// from two MCValue's LHS and RHS where +/// Result = LHS + RHS +/// and +/// Result = (LHS_A - LHS_B + LHS_Cst) + (RHS_A - RHS_B + RHS_Cst). +/// +/// This routine attempts to aggresively fold the operands such that the result +/// is representable in an MCValue, but may not always succeed. +/// +/// \returns True on success, false if the result is not representable in an +/// MCValue. + +/// NOTE: It is really important to have both the Asm and Layout arguments. +/// They might look redundant, but this function can be used before layout +/// is done (see the object streamer for example) and having the Asm argument +/// lets us avoid relaxations early. +static bool EvaluateSymbolicAdd(const MCAssembler *Asm, + const MCAsmLayout *Layout, + const SectionAddrMap *Addrs, + bool InSet, const MCValue &LHS,const MCSymbolRefExpr *RHS_A, const MCSymbolRefExpr *RHS_B, int64_t RHS_Cst, MCValue &Res) { - // We can't add or subtract two symbols. - if ((LHS.getSymA() && RHS_A) || - (LHS.getSymB() && RHS_B)) - return false; - - const MCSymbolRefExpr *A = LHS.getSymA() ? LHS.getSymA() : RHS_A; - const MCSymbolRefExpr *B = LHS.getSymB() ? LHS.getSymB() : RHS_B; - if (B) { - // If we have a negated symbol, then we must have also have a non-negated - // symbol in order to encode the expression. We can do this check later to - // permit expressions which eventually fold to a representable form -- such - // as (a + (0 - b)) -- if necessary. - if (!A) - return false; + // FIXME: This routine (and other evaluation parts) are *incredibly* sloppy + // about dealing with modifiers. This will ultimately bite us, one day. + const MCSymbolRefExpr *LHS_A = LHS.getSymA(); + const MCSymbolRefExpr *LHS_B = LHS.getSymB(); + int64_t LHS_Cst = LHS.getConstant(); + + // Fold the result constant immediately. + int64_t Result_Cst = LHS_Cst + RHS_Cst; + + assert((!Layout || Asm) && + "Must have an assembler object if layout is given!"); + + // If we have a layout, we can fold resolved differences. + if (Asm) { + // First, fold out any differences which are fully resolved. By + // reassociating terms in + // Result = (LHS_A - LHS_B + LHS_Cst) + (RHS_A - RHS_B + RHS_Cst). + // we have the four possible differences: + // (LHS_A - LHS_B), + // (LHS_A - RHS_B), + // (RHS_A - LHS_B), + // (RHS_A - RHS_B). + // Since we are attempting to be as aggresive as possible about folding, we + // attempt to evaluate each possible alternative. + AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, LHS_A, LHS_B, + Result_Cst); + AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, LHS_A, RHS_B, + Result_Cst); + AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, RHS_A, LHS_B, + Result_Cst); + AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, RHS_A, RHS_B, + Result_Cst); } - // Absolutize symbol differences between defined symbols when we have a - // layout object and the target requests it. - - if (Layout && A && B) { - const MCSymbol &SA = A->getSymbol(); - const MCSymbol &SB = B->getSymbol(); - const MCObjectFormat &F = - Layout->getAssembler().getBackend().getObjectFormat(); - if (SA.isDefined() && SB.isDefined() && F.isAbsolute(InSet, SA, SB)) { - const MCAssembler &Asm = Layout->getAssembler(); - MCSymbolData &AD = Asm.getSymbolData(A->getSymbol()); - MCSymbolData &BD = Asm.getSymbolData(B->getSymbol()); - Res = MCValue::get(+ Layout->getSymbolAddress(&AD) - - Layout->getSymbolAddress(&BD) - + LHS.getConstant() - + RHS_Cst); - return true; - } - } + // We can't represent the addition or subtraction of two symbols. + if ((LHS_A && RHS_A) || (LHS_B && RHS_B)) + return false; + // At this point, we have at most one additive symbol and one subtractive + // symbol -- find them. + const MCSymbolRefExpr *A = LHS_A ? LHS_A : RHS_A; + const MCSymbolRefExpr *B = LHS_B ? LHS_B : RHS_B; + + // If we have a negated symbol, then we must have also have a non-negated + // symbol in order to encode the expression. + if (B && !A) + return false; - Res = MCValue::get(A, B, LHS.getConstant() + RHS_Cst); + Res = MCValue::get(A, B, Result_Cst); return true; } bool MCExpr::EvaluateAsRelocatable(MCValue &Res, - const MCAsmLayout *Layout) const { - return EvaluateAsRelocatableImpl(Res, Layout, false); + const MCAsmLayout &Layout) const { + return EvaluateAsRelocatableImpl(Res, &Layout.getAssembler(), &Layout, + 0, false); } bool MCExpr::EvaluateAsRelocatableImpl(MCValue &Res, + const MCAssembler *Asm, const MCAsmLayout *Layout, + const SectionAddrMap *Addrs, bool InSet) const { ++stats::MCExprEvaluate; @@ -337,7 +441,9 @@ bool MCExpr::EvaluateAsRelocatableImpl(MCValue &Res, // Evaluate recursively if this is a variable. if (Sym.isVariable() && SRE->getKind() == MCSymbolRefExpr::VK_None) { - bool Ret = Sym.getVariableValue()->EvaluateAsRelocatableImpl(Res, Layout, + bool Ret = Sym.getVariableValue()->EvaluateAsRelocatableImpl(Res, Asm, + Layout, + Addrs, true); // If we failed to simplify this to a constant, let the target // handle it. @@ -353,7 +459,8 @@ bool MCExpr::EvaluateAsRelocatableImpl(MCValue &Res, const MCUnaryExpr *AUE = cast<MCUnaryExpr>(this); MCValue Value; - if (!AUE->getSubExpr()->EvaluateAsRelocatableImpl(Value, Layout, InSet)) + if (!AUE->getSubExpr()->EvaluateAsRelocatableImpl(Value, Asm, Layout, + Addrs, InSet)) return false; switch (AUE->getOpcode()) { @@ -386,8 +493,10 @@ bool MCExpr::EvaluateAsRelocatableImpl(MCValue &Res, const MCBinaryExpr *ABE = cast<MCBinaryExpr>(this); MCValue LHSValue, RHSValue; - if (!ABE->getLHS()->EvaluateAsRelocatableImpl(LHSValue, Layout, InSet) || - !ABE->getRHS()->EvaluateAsRelocatableImpl(RHSValue, Layout, InSet)) + if (!ABE->getLHS()->EvaluateAsRelocatableImpl(LHSValue, Asm, Layout, + Addrs, InSet) || + !ABE->getRHS()->EvaluateAsRelocatableImpl(RHSValue, Asm, Layout, + Addrs, InSet)) return false; // We only support a few operations on non-constant expressions, handle @@ -398,13 +507,13 @@ bool MCExpr::EvaluateAsRelocatableImpl(MCValue &Res, return false; case MCBinaryExpr::Sub: // Negate RHS and add. - return EvaluateSymbolicAdd(Layout, InSet, LHSValue, + return EvaluateSymbolicAdd(Asm, Layout, Addrs, InSet, LHSValue, RHSValue.getSymB(), RHSValue.getSymA(), -RHSValue.getConstant(), Res); case MCBinaryExpr::Add: - return EvaluateSymbolicAdd(Layout, InSet, LHSValue, + return EvaluateSymbolicAdd(Asm, Layout, Addrs, InSet, LHSValue, RHSValue.getSymA(), RHSValue.getSymB(), RHSValue.getConstant(), Res); |