Check in LLVM r95781.
diff --git a/lib/MC/MCExpr.cpp b/lib/MC/MCExpr.cpp
new file mode 100644
index 0000000..e419043
--- /dev/null
+++ b/lib/MC/MCExpr.cpp
@@ -0,0 +1,287 @@
+//===- MCExpr.cpp - Assembly Level Expression Implementation --------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCSymbol.h"
+#include "llvm/MC/MCValue.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+using namespace llvm;
+
+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: {
+ const MCSymbol &Sym = cast<MCSymbolRefExpr>(*this).getSymbol();
+
+ // Parenthesize names that start with $ so that they don't look like
+ // absolute names.
+ if (Sym.getName()[0] == '$')
+ OS << '(' << Sym << ')';
+ else
+ OS << Sym;
+ return;
+ }
+
+ case MCExpr::Unary: {
+ const MCUnaryExpr &UE = cast<MCUnaryExpr>(*this);
+ switch (UE.getOpcode()) {
+ default: assert(0 && "Invalid opcode!");
+ case MCUnaryExpr::LNot: OS << '!'; break;
+ case MCUnaryExpr::Minus: OS << '-'; break;
+ case MCUnaryExpr::Not: OS << '~'; break;
+ case MCUnaryExpr::Plus: OS << '+'; break;
+ }
+ OS << *UE.getSubExpr();
+ return;
+ }
+
+ case MCExpr::Binary: {
+ const MCBinaryExpr &BE = cast<MCBinaryExpr>(*this);
+
+ // 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:
+ // 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::GT: OS << '>'; break;
+ case MCBinaryExpr::GTE: OS << ">="; break;
+ case MCBinaryExpr::LAnd: OS << "&&"; break;
+ case MCBinaryExpr::LOr: OS << "||"; break;
+ case MCBinaryExpr::LT: OS << '<'; break;
+ case MCBinaryExpr::LTE: OS << "<="; break;
+ case MCBinaryExpr::Mod: OS << '%'; break;
+ case MCBinaryExpr::Mul: OS << '*'; break;
+ case MCBinaryExpr::NE: OS << "!="; break;
+ case MCBinaryExpr::Or: OS << '|'; break;
+ case MCBinaryExpr::Shl: OS << "<<"; break;
+ case MCBinaryExpr::Shr: OS << ">>"; break;
+ case MCBinaryExpr::Sub: OS << '-'; break;
+ case MCBinaryExpr::Xor: OS << '^'; break;
+ }
+
+ // 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;
+ }
+ }
+
+ assert(0 && "Invalid expression kind!");
+}
+
+void MCExpr::dump() const {
+ print(dbgs());
+ dbgs() << '\n';
+}
+
+/* *** */
+
+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) {
+ return new (Ctx) MCUnaryExpr(Opc, Expr);
+}
+
+const MCConstantExpr *MCConstantExpr::Create(int64_t Value, MCContext &Ctx) {
+ return new (Ctx) MCConstantExpr(Value);
+}
+
+const MCSymbolRefExpr *MCSymbolRefExpr::Create(const MCSymbol *Sym,
+ MCContext &Ctx) {
+ return new (Ctx) MCSymbolRefExpr(Sym);
+}
+
+const MCSymbolRefExpr *MCSymbolRefExpr::Create(StringRef Name, MCContext &Ctx) {
+ return Create(Ctx.GetOrCreateSymbol(Name), Ctx);
+}
+
+void MCTargetExpr::Anchor() {}
+
+/* *** */
+
+bool MCExpr::EvaluateAsAbsolute(int64_t &Res) const {
+ MCValue Value;
+
+ if (!EvaluateAsRelocatable(Value) || !Value.isAbsolute())
+ 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,
+ MCValue &Res) {
+ // We can't add or subtract two symbols.
+ if ((LHS.getSymA() && RHS_A) ||
+ (LHS.getSymB() && 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;
+ }
+ Res = MCValue::get(A, B, LHS.getConstant() + RHS_Cst);
+ return true;
+}
+
+bool MCExpr::EvaluateAsRelocatable(MCValue &Res) const {
+ switch (getKind()) {
+ case Target:
+ return cast<MCTargetExpr>(this)->EvaluateAsRelocatableImpl(Res);
+
+ case Constant:
+ Res = MCValue::get(cast<MCConstantExpr>(this)->getValue());
+ return true;
+
+ case SymbolRef: {
+ const MCSymbol &Sym = cast<MCSymbolRefExpr>(this)->getSymbol();
+
+ // Evaluate recursively if this is a variable.
+ if (Sym.isVariable())
+ return Sym.getValue()->EvaluateAsRelocatable(Res);
+
+ Res = MCValue::get(&Sym, 0, 0);
+ return true;
+ }
+
+ case Unary: {
+ const MCUnaryExpr *AUE = cast<MCUnaryExpr>(this);
+ MCValue Value;
+
+ if (!AUE->getSubExpr()->EvaluateAsRelocatable(Value))
+ return false;
+
+ switch (AUE->getOpcode()) {
+ case MCUnaryExpr::LNot:
+ if (!Value.isAbsolute())
+ return false;
+ Res = MCValue::get(!Value.getConstant());
+ break;
+ case MCUnaryExpr::Minus:
+ /// -(a - b + const) ==> (b - a - const)
+ if (Value.getSymA() && !Value.getSymB())
+ return false;
+ Res = MCValue::get(Value.getSymB(), Value.getSymA(),
+ -Value.getConstant());
+ break;
+ case MCUnaryExpr::Not:
+ if (!Value.isAbsolute())
+ return false;
+ Res = MCValue::get(~Value.getConstant());
+ break;
+ case MCUnaryExpr::Plus:
+ Res = Value;
+ break;
+ }
+
+ return true;
+ }
+
+ case Binary: {
+ const MCBinaryExpr *ABE = cast<MCBinaryExpr>(this);
+ MCValue LHSValue, RHSValue;
+
+ if (!ABE->getLHS()->EvaluateAsRelocatable(LHSValue) ||
+ !ABE->getRHS()->EvaluateAsRelocatable(RHSValue))
+ return false;
+
+ // We only support a few operations on non-constant expressions, handle
+ // those first.
+ if (!LHSValue.isAbsolute() || !RHSValue.isAbsolute()) {
+ switch (ABE->getOpcode()) {
+ default:
+ return false;
+ case MCBinaryExpr::Sub:
+ // Negate RHS and add.
+ return EvaluateSymbolicAdd(LHSValue,
+ RHSValue.getSymB(), RHSValue.getSymA(),
+ -RHSValue.getConstant(),
+ Res);
+
+ case MCBinaryExpr::Add:
+ return EvaluateSymbolicAdd(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 and right shifts
+ // differently from Apple as.
+ int64_t LHS = LHSValue.getConstant(), RHS = RHSValue.getConstant();
+ int64_t Result = 0;
+ switch (ABE->getOpcode()) {
+ case MCBinaryExpr::Add: Result = LHS + RHS; break;
+ case MCBinaryExpr::And: Result = LHS & RHS; break;
+ case MCBinaryExpr::Div: Result = LHS / RHS; break;
+ case MCBinaryExpr::EQ: Result = LHS == RHS; break;
+ case MCBinaryExpr::GT: Result = LHS > RHS; break;
+ case MCBinaryExpr::GTE: Result = LHS >= RHS; break;
+ case MCBinaryExpr::LAnd: Result = LHS && RHS; break;
+ case MCBinaryExpr::LOr: Result = LHS || RHS; break;
+ case MCBinaryExpr::LT: Result = LHS < RHS; break;
+ case MCBinaryExpr::LTE: Result = LHS <= RHS; break;
+ case MCBinaryExpr::Mod: Result = LHS % RHS; break;
+ case MCBinaryExpr::Mul: Result = LHS * RHS; break;
+ case MCBinaryExpr::NE: Result = LHS != RHS; break;
+ case MCBinaryExpr::Or: Result = LHS | RHS; break;
+ case MCBinaryExpr::Shl: Result = LHS << RHS; break;
+ case MCBinaryExpr::Shr: Result = LHS >> RHS; break;
+ case MCBinaryExpr::Sub: Result = LHS - RHS; break;
+ case MCBinaryExpr::Xor: Result = LHS ^ RHS; break;
+ }
+
+ Res = MCValue::get(Result);
+ return true;
+ }
+ }
+
+ assert(0 && "Invalid assembly expression kind!");
+ return false;
+}