//
//===----------------------------------------------------------------------===//
+#define DEBUG_TYPE "mcexpr"
#include "llvm/MC/MCExpr.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/ADT/StringSwitch.h"
+#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"
#include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetAsmBackend.h"
using namespace llvm;
-void MCExpr::print(raw_ostream &OS, const MCAsmInfo *MAI) const {
+namespace {
+namespace stats {
+STATISTIC(MCExprEvaluate, "Number of MCExpr evaluations");
+}
+}
+
+void MCExpr::print(raw_ostream &OS) const {
switch (getKind()) {
+ case MCExpr::Target:
+ return cast<MCTargetExpr>(this)->PrintImpl(OS);
case MCExpr::Constant:
OS << cast<MCConstantExpr>(*this).getValue();
return;
- case MCExpr::SymbolRef:
- cast<MCSymbolRefExpr>(*this).getSymbol().print(OS, MAI);
+ case MCExpr::SymbolRef: {
+ const MCSymbolRefExpr &SRE = cast<MCSymbolRefExpr>(*this);
+ const MCSymbol &Sym = SRE.getSymbol();
+ // Parenthesize names that start with $ so that they don't look like
+ // 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());
+ UseParens = true;
+ }
+
+ if (UseParens)
+ OS << '(' << Sym << ')';
+ else
+ OS << Sym;
+
+ if (SRE.getKind() == MCSymbolRefExpr::VK_ARM_PLT ||
+ SRE.getKind() == MCSymbolRefExpr::VK_ARM_TLSGD ||
+ SRE.getKind() == MCSymbolRefExpr::VK_ARM_GOT ||
+ SRE.getKind() == MCSymbolRefExpr::VK_ARM_GOTOFF ||
+ SRE.getKind() == MCSymbolRefExpr::VK_ARM_TPOFF ||
+ 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());
+
return;
+ }
case MCExpr::Unary: {
const MCUnaryExpr &UE = cast<MCUnaryExpr>(*this);
case MCUnaryExpr::Not: OS << '~'; break;
case MCUnaryExpr::Plus: OS << '+'; break;
}
- UE.getSubExpr()->print(OS, MAI);
+ OS << *UE.getSubExpr();
return;
}
case MCExpr::Binary: {
const MCBinaryExpr &BE = cast<MCBinaryExpr>(*this);
- OS << '(';
- BE.getLHS()->print(OS, MAI);
- OS << ' ';
+
+ // Only print parens around the LHS if it is non-trivial.
+ if (isa<MCConstantExpr>(BE.getLHS()) || isa<MCSymbolRefExpr>(BE.getLHS())) {
+ OS << *BE.getLHS();
+ } else {
+ OS << '(' << *BE.getLHS() << ')';
+ }
+
switch (BE.getOpcode()) {
default: assert(0 && "Invalid opcode!");
- case MCBinaryExpr::Add: OS << '+'; break;
+ case MCBinaryExpr::Add:
+ // Print "X-42" instead of "X+-42".
+ if (const MCConstantExpr *RHSC = dyn_cast<MCConstantExpr>(BE.getRHS())) {
+ if (RHSC->getValue() < 0) {
+ OS << RHSC->getValue();
+ return;
+ }
+ }
+
+ OS << '+';
+ break;
case MCBinaryExpr::And: OS << '&'; break;
case MCBinaryExpr::Div: OS << '/'; break;
case MCBinaryExpr::EQ: OS << "=="; break;
case MCBinaryExpr::Sub: OS << '-'; break;
case MCBinaryExpr::Xor: OS << '^'; break;
}
- OS << ' ';
- BE.getRHS()->print(OS, MAI);
- OS << ')';
+
+ // Only print parens around the LHS if it is non-trivial.
+ if (isa<MCConstantExpr>(BE.getRHS()) || isa<MCSymbolRefExpr>(BE.getRHS())) {
+ OS << *BE.getRHS();
+ } else {
+ OS << '(' << *BE.getRHS() << ')';
+ }
return;
}
}
}
void MCExpr::dump() const {
- print(errs(), 0);
- errs() << '\n';
+ print(dbgs());
+ dbgs() << '\n';
}
/* *** */
-const MCBinaryExpr * MCBinaryExpr::Create(Opcode Opc,
- const MCExpr *LHS,
- const MCExpr *RHS,
- MCContext &Ctx) {
+const MCBinaryExpr *MCBinaryExpr::Create(Opcode Opc, const MCExpr *LHS,
+ const MCExpr *RHS, MCContext &Ctx) {
return new (Ctx) MCBinaryExpr(Opc, LHS, RHS);
}
-const MCUnaryExpr * MCUnaryExpr::Create(Opcode Opc,
- const MCExpr *Expr,
- MCContext &Ctx) {
+const MCUnaryExpr *MCUnaryExpr::Create(Opcode Opc, const MCExpr *Expr,
+ MCContext &Ctx) {
return new (Ctx) MCUnaryExpr(Opc, Expr);
}
return new (Ctx) MCConstantExpr(Value);
}
+/* *** */
+
const MCSymbolRefExpr *MCSymbolRefExpr::Create(const MCSymbol *Sym,
+ VariantKind Kind,
MCContext &Ctx) {
- return new (Ctx) MCSymbolRefExpr(Sym);
+ return new (Ctx) MCSymbolRefExpr(Sym, Kind);
+}
+
+const MCSymbolRefExpr *MCSymbolRefExpr::Create(StringRef Name, VariantKind Kind,
+ MCContext &Ctx) {
+ return Create(Ctx.GetOrCreateSymbol(Name), Kind, Ctx);
+}
+
+StringRef MCSymbolRefExpr::getVariantKindName(VariantKind Kind) {
+ switch (Kind) {
+ default:
+ case VK_Invalid: return "<<invalid>>";
+ case VK_None: return "<<none>>";
+
+ case VK_GOT: return "GOT";
+ case VK_GOTOFF: return "GOTOFF";
+ case VK_GOTPCREL: return "GOTPCREL";
+ case VK_GOTTPOFF: return "GOTTPOFF";
+ case VK_INDNTPOFF: return "INDNTPOFF";
+ case VK_NTPOFF: return "NTPOFF";
+ case VK_GOTNTPOFF: return "GOTNTPOFF";
+ case VK_PLT: return "PLT";
+ case VK_TLSGD: return "TLSGD";
+ case VK_TLSLD: return "TLSLD";
+ case VK_TLSLDM: return "TLSLDM";
+ 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 "(tlsgd)";
+ case VK_PPC_TOC: return "toc";
+ case VK_PPC_HA16: return "ha16";
+ case VK_PPC_LO16: return "lo16";
+ }
+}
+
+MCSymbolRefExpr::VariantKind
+MCSymbolRefExpr::getVariantKindForName(StringRef Name) {
+ return StringSwitch<VariantKind>(Name)
+ .Case("GOT", VK_GOT)
+ .Case("GOTOFF", VK_GOTOFF)
+ .Case("GOTPCREL", VK_GOTPCREL)
+ .Case("GOTTPOFF", VK_GOTTPOFF)
+ .Case("INDNTPOFF", VK_INDNTPOFF)
+ .Case("NTPOFF", VK_NTPOFF)
+ .Case("GOTNTPOFF", VK_GOTNTPOFF)
+ .Case("PLT", VK_PLT)
+ .Case("TLSGD", VK_TLSGD)
+ .Case("TLSLD", VK_TLSLD)
+ .Case("TLSLDM", VK_TLSLDM)
+ .Case("TPOFF", VK_TPOFF)
+ .Case("DTPOFF", VK_DTPOFF)
+ .Case("TLVP", VK_TLVP)
+ .Default(VK_Invalid);
}
/* *** */
-bool MCExpr::EvaluateAsAbsolute(MCContext &Ctx, int64_t &Res) const {
+void MCTargetExpr::Anchor() {}
+
+/* *** */
+
+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;
-
- if (!EvaluateAsRelocatable(Ctx, Value) || !Value.isAbsolute())
+
+ // Fast path constants.
+ if (const MCConstantExpr *CE = dyn_cast<MCConstantExpr>(this)) {
+ Res = CE->getValue();
+ return true;
+ }
+
+ if (!EvaluateAsRelocatableImpl(Value, Asm, Layout, Addrs, Addrs) ||
+ !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->getSymbolOffset(
+ &Layout->getAssembler().getSymbolData(Value.getSymA()->getSymbol()));
+ }
+ if (Value.getSymB()) {
+ Res -= Layout->getSymbolOffset(
+ &Layout->getAssembler().getSymbolData(Value.getSymB()->getSymbol()));
+ }
+ }
return false;
+ }
Res = Value.getConstant();
return true;
}
-static bool EvaluateSymbolicAdd(const MCValue &LHS, const MCSymbol *RHS_A,
- const MCSymbol *RHS_B, int64_t RHS_Cst,
+/// \brief Helper method for \see EvaluateSymbolAdd().
+static void AttemptToFoldSymbolOffsetDifference(const MCAsmLayout *Layout,
+ const MCSymbolRefExpr *&A,
+ const MCSymbolRefExpr *&B,
+ int64_t &Addend) {
+ const MCAssembler &Asm = Layout->getAssembler();
+
+ if (A && B &&
+ Asm.getWriter().IsSymbolRefDifferenceFullyResolved(Asm, A, B)) {
+ // Eagerly evaluate.
+ Addend += (Layout->getSymbolOffset(&Asm.getSymbolData(A->getSymbol())) -
+ Layout->getSymbolOffset(&Asm.getSymbolData(B->getSymbol())));
+
+ // 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 relocations.
+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))
+ // 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;
+
+ // If we have a layout, we can fold resolved differences.
+ if (Layout) {
+ // 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(Layout, LHS_A, LHS_B, Result_Cst);
+ AttemptToFoldSymbolOffsetDifference(Layout, LHS_A, RHS_B, Result_Cst);
+ AttemptToFoldSymbolOffsetDifference(Layout, RHS_A, LHS_B, Result_Cst);
+ AttemptToFoldSymbolOffsetDifference(Layout, RHS_A, RHS_B, Result_Cst);
+ }
+
+ // We can't represent the addition or subtraction of two symbols.
+ if ((LHS_A && RHS_A) || (LHS_B && RHS_B))
return false;
- const MCSymbol *A = LHS.getSymA() ? LHS.getSymA() : RHS_A;
- const MCSymbol *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;
+ // 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;
+
+ // Absolutize symbol differences between defined symbols when we have a
+ // layout object and the target requests it.
+
+ assert((!Layout || Asm) &&
+ "Must have an assembler object if layout is given!");
+
+ if (Asm && A && B) {
+ const MCSymbol &SA = A->getSymbol();
+ const MCSymbol &SB = B->getSymbol();
+ const MCObjectFormat &F = Asm->getBackend().getObjectFormat();
+ if (SA.isDefined() && SB.isDefined() && F.isAbsolute(InSet, SA, SB)) {
+ MCSymbolData &AD = Asm->getSymbolData(A->getSymbol());
+ MCSymbolData &BD = Asm->getSymbolData(B->getSymbol());
+
+ if (AD.getFragment() == BD.getFragment()) {
+ Res = MCValue::get(+ AD.getOffset()
+ - BD.getOffset()
+ + Result_Cst);
+ return true;
+ }
+
+ if (Layout) {
+ const MCSectionData &SecA = *AD.getFragment()->getParent();
+ const MCSectionData &SecB = *BD.getFragment()->getParent();
+ int64_t Val = + Layout->getSymbolOffset(&AD)
+ - Layout->getSymbolOffset(&BD)
+ + Result_Cst;
+ if (&SecA != &SecB) {
+ if (!Addrs)
+ return false;
+ Val += Addrs->lookup(&SecA);
+ Val -= Addrs->lookup(&SecB);
+ }
+ Res = MCValue::get(Val);
+ return true;
+ }
+ }
}
- Res = MCValue::get(A, B, LHS.getConstant() + RHS_Cst);
+
+ Res = MCValue::get(A, B, Result_Cst);
return true;
}
-bool MCExpr::EvaluateAsRelocatable(MCContext &Ctx, MCValue &Res) const {
+bool MCExpr::EvaluateAsRelocatable(MCValue &Res,
+ const MCAsmLayout *Layout) const {
+ if (Layout)
+ return EvaluateAsRelocatableImpl(Res, &Layout->getAssembler(), Layout,
+ 0, false);
+ else
+ return EvaluateAsRelocatableImpl(Res, 0, 0, 0, false);
+}
+
+bool MCExpr::EvaluateAsRelocatableImpl(MCValue &Res,
+ const MCAssembler *Asm,
+ const MCAsmLayout *Layout,
+ const SectionAddrMap *Addrs,
+ bool InSet) const {
+ ++stats::MCExprEvaluate;
+
switch (getKind()) {
+ case Target:
+ return cast<MCTargetExpr>(this)->EvaluateAsRelocatableImpl(Res, Layout);
+
case Constant:
Res = MCValue::get(cast<MCConstantExpr>(this)->getValue());
return true;
case SymbolRef: {
- const MCSymbol &Sym = cast<MCSymbolRefExpr>(this)->getSymbol();
- if (const MCValue *Value = Ctx.GetSymbolValue(&Sym))
- Res = *Value;
- else
- Res = MCValue::get(&Sym, 0, 0);
+ const MCSymbolRefExpr *SRE = cast<MCSymbolRefExpr>(this);
+ const MCSymbol &Sym = SRE->getSymbol();
+
+ // Evaluate recursively if this is a variable.
+ if (Sym.isVariable() && SRE->getKind() == MCSymbolRefExpr::VK_None) {
+ bool Ret = Sym.getVariableValue()->EvaluateAsRelocatableImpl(Res, Asm,
+ Layout,
+ Addrs,
+ 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;
}
const MCUnaryExpr *AUE = cast<MCUnaryExpr>(this);
MCValue Value;
- if (!AUE->getSubExpr()->EvaluateAsRelocatable(Ctx, Value))
+ if (!AUE->getSubExpr()->EvaluateAsRelocatableImpl(Value, Asm, Layout,
+ Addrs, InSet))
return false;
switch (AUE->getOpcode()) {
/// -(a - b + const) ==> (b - a - const)
if (Value.getSymA() && !Value.getSymB())
return false;
- Res = MCValue::get(Value.getSymB(), Value.getSymA(),
- -Value.getConstant());
+ Res = MCValue::get(Value.getSymB(), Value.getSymA(),
+ -Value.getConstant());
break;
case MCUnaryExpr::Not:
if (!Value.isAbsolute())
return false;
- Res = MCValue::get(~Value.getConstant());
+ Res = MCValue::get(~Value.getConstant());
break;
case MCUnaryExpr::Plus:
Res = Value;
case Binary: {
const MCBinaryExpr *ABE = cast<MCBinaryExpr>(this);
MCValue LHSValue, RHSValue;
-
- if (!ABE->getLHS()->EvaluateAsRelocatable(Ctx, LHSValue) ||
- !ABE->getRHS()->EvaluateAsRelocatable(Ctx, RHSValue))
+
+ 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
return false;
case MCBinaryExpr::Sub:
// Negate RHS and add.
- return EvaluateSymbolicAdd(LHSValue,
+ return EvaluateSymbolicAdd(Asm, Layout, Addrs, InSet, LHSValue,
RHSValue.getSymB(), RHSValue.getSymA(),
-RHSValue.getConstant(),
Res);
case MCBinaryExpr::Add:
- return EvaluateSymbolicAdd(LHSValue,
+ return EvaluateSymbolicAdd(Asm, Layout, Addrs, InSet, LHSValue,
RHSValue.getSymA(), RHSValue.getSymB(),
RHSValue.getConstant(),
Res);
}
// FIXME: We need target hooks for the evaluation. It may be limited in
- // width, and gas defines the result of comparisons differently from Apple
- // as (the result is sign extended).
+ // width, and gas defines the result of comparisons and right shifts
+ // differently from Apple as.
int64_t LHS = LHSValue.getConstant(), RHS = RHSValue.getConstant();
int64_t Result = 0;
switch (ABE->getOpcode()) {
projects / oota-llvm.git / blobdiff