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//===- AsmExpr.cpp - Assembly file expressions ----------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "AsmExpr.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCValue.h"
using namespace llvm;
AsmExpr::~AsmExpr() {
}
bool AsmExpr::EvaluateAsAbsolute(MCContext &Ctx, int64_t &Res) const {
switch (getKind()) {
default:
assert(0 && "Invalid assembly expression kind!");
case Constant:
Res = cast<AsmConstantExpr>(this)->getValue();
return true;
case SymbolRef: {
MCSymbol *Sym = cast<AsmSymbolRefExpr>(this)->getSymbol();
const MCValue *Value = Ctx.GetSymbolValue(Sym);
// FIXME: Return more information about the failure.
if (!Value || !Value->isConstant())
return false;
Res = Value->getConstant();
return true;
}
case Unary: {
const AsmUnaryExpr *AUE = cast<AsmUnaryExpr>(this);
int64_t Value;
if (!AUE->getSubExpr()->EvaluateAsAbsolute(Ctx, Value))
return false;
switch (AUE->getOpcode()) {
case AsmUnaryExpr::LNot: Res = !Value; break;
case AsmUnaryExpr::Minus: Res = -Value; break;
case AsmUnaryExpr::Not: Res = ~Value; break;
case AsmUnaryExpr::Plus: Res = +Value; break;
}
return true;
}
case Binary: {
const AsmBinaryExpr *ABE = cast<AsmBinaryExpr>(this);
int64_t LHS, RHS;
if (!ABE->getLHS()->EvaluateAsAbsolute(Ctx, LHS) ||
!ABE->getRHS()->EvaluateAsAbsolute(Ctx, RHS))
return false;
// 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).
switch (ABE->getOpcode()) {
case AsmBinaryExpr::Add: Res = LHS + RHS; break;
case AsmBinaryExpr::And: Res = LHS & RHS; break;
case AsmBinaryExpr::Div: Res = LHS / RHS; break;
case AsmBinaryExpr::EQ: Res = LHS == RHS; break;
case AsmBinaryExpr::GT: Res = LHS > RHS; break;
case AsmBinaryExpr::GTE: Res = LHS >= RHS; break;
case AsmBinaryExpr::LAnd: Res = LHS && RHS; break;
case AsmBinaryExpr::LOr: Res = LHS || RHS; break;
case AsmBinaryExpr::LT: Res = LHS < RHS; break;
case AsmBinaryExpr::LTE: Res = LHS <= RHS; break;
case AsmBinaryExpr::Mod: Res = LHS % RHS; break;
case AsmBinaryExpr::Mul: Res = LHS * RHS; break;
case AsmBinaryExpr::NE: Res = LHS != RHS; break;
case AsmBinaryExpr::Or: Res = LHS | RHS; break;
case AsmBinaryExpr::Shl: Res = LHS << RHS; break;
case AsmBinaryExpr::Shr: Res = LHS >> RHS; break;
case AsmBinaryExpr::Sub: Res = LHS - RHS; break;
case AsmBinaryExpr::Xor: Res = LHS ^ RHS; break;
}
return true;
}
}
}
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