forked from OSchip/llvm-project
503 lines
17 KiB
C++
503 lines
17 KiB
C++
//===- MCExpr.cpp - Assembly Level Expression Implementation --------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "mcexpr"
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#include "llvm/MC/MCExpr.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/ADT/StringSwitch.h"
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#include "llvm/MC/MCAsmLayout.h"
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#include "llvm/MC/MCAssembler.h"
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#include "llvm/MC/MCContext.h"
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#include "llvm/MC/MCObjectFormat.h"
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#include "llvm/MC/MCSymbol.h"
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#include "llvm/MC/MCValue.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/Target/TargetAsmBackend.h"
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using namespace llvm;
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namespace {
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namespace stats {
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STATISTIC(MCExprEvaluate, "Number of MCExpr evaluations");
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}
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}
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void MCExpr::print(raw_ostream &OS) const {
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switch (getKind()) {
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case MCExpr::Target:
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return cast<MCTargetExpr>(this)->PrintImpl(OS);
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case MCExpr::Constant:
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OS << cast<MCConstantExpr>(*this).getValue();
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return;
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case MCExpr::SymbolRef: {
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const MCSymbolRefExpr &SRE = cast<MCSymbolRefExpr>(*this);
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const MCSymbol &Sym = SRE.getSymbol();
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// Parenthesize names that start with $ so that they don't look like
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// absolute names.
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bool UseParens = Sym.getName()[0] == '$';
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if (SRE.getKind() == MCSymbolRefExpr::VK_ARM_HI16 ||
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SRE.getKind() == MCSymbolRefExpr::VK_ARM_LO16)
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OS << MCSymbolRefExpr::getVariantKindName(SRE.getKind());
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if (SRE.getKind() == MCSymbolRefExpr::VK_PPC_HA16 ||
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SRE.getKind() == MCSymbolRefExpr::VK_PPC_LO16) {
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OS << MCSymbolRefExpr::getVariantKindName(SRE.getKind());
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UseParens = true;
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}
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if (UseParens)
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OS << '(' << Sym << ')';
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else
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OS << Sym;
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if (SRE.getKind() == MCSymbolRefExpr::VK_ARM_PLT ||
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SRE.getKind() == MCSymbolRefExpr::VK_ARM_TLSGD ||
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SRE.getKind() == MCSymbolRefExpr::VK_ARM_GOT ||
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SRE.getKind() == MCSymbolRefExpr::VK_ARM_GOTOFF ||
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SRE.getKind() == MCSymbolRefExpr::VK_ARM_TPOFF ||
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SRE.getKind() == MCSymbolRefExpr::VK_ARM_GOTTPOFF)
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OS << MCSymbolRefExpr::getVariantKindName(SRE.getKind());
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else if (SRE.getKind() != MCSymbolRefExpr::VK_None &&
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SRE.getKind() != MCSymbolRefExpr::VK_ARM_HI16 &&
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SRE.getKind() != MCSymbolRefExpr::VK_ARM_LO16 &&
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SRE.getKind() != MCSymbolRefExpr::VK_PPC_HA16 &&
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SRE.getKind() != MCSymbolRefExpr::VK_PPC_LO16)
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OS << '@' << MCSymbolRefExpr::getVariantKindName(SRE.getKind());
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return;
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}
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case MCExpr::Unary: {
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const MCUnaryExpr &UE = cast<MCUnaryExpr>(*this);
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switch (UE.getOpcode()) {
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default: assert(0 && "Invalid opcode!");
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case MCUnaryExpr::LNot: OS << '!'; break;
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case MCUnaryExpr::Minus: OS << '-'; break;
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case MCUnaryExpr::Not: OS << '~'; break;
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case MCUnaryExpr::Plus: OS << '+'; break;
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}
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OS << *UE.getSubExpr();
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return;
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}
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case MCExpr::Binary: {
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const MCBinaryExpr &BE = cast<MCBinaryExpr>(*this);
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// Only print parens around the LHS if it is non-trivial.
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if (isa<MCConstantExpr>(BE.getLHS()) || isa<MCSymbolRefExpr>(BE.getLHS())) {
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OS << *BE.getLHS();
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} else {
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OS << '(' << *BE.getLHS() << ')';
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}
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switch (BE.getOpcode()) {
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default: assert(0 && "Invalid opcode!");
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case MCBinaryExpr::Add:
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// Print "X-42" instead of "X+-42".
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if (const MCConstantExpr *RHSC = dyn_cast<MCConstantExpr>(BE.getRHS())) {
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if (RHSC->getValue() < 0) {
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OS << RHSC->getValue();
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return;
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}
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}
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OS << '+';
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break;
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case MCBinaryExpr::And: OS << '&'; break;
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case MCBinaryExpr::Div: OS << '/'; break;
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case MCBinaryExpr::EQ: OS << "=="; break;
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case MCBinaryExpr::GT: OS << '>'; break;
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case MCBinaryExpr::GTE: OS << ">="; break;
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case MCBinaryExpr::LAnd: OS << "&&"; break;
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case MCBinaryExpr::LOr: OS << "||"; break;
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case MCBinaryExpr::LT: OS << '<'; break;
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case MCBinaryExpr::LTE: OS << "<="; break;
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case MCBinaryExpr::Mod: OS << '%'; break;
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case MCBinaryExpr::Mul: OS << '*'; break;
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case MCBinaryExpr::NE: OS << "!="; break;
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case MCBinaryExpr::Or: OS << '|'; break;
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case MCBinaryExpr::Shl: OS << "<<"; break;
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case MCBinaryExpr::Shr: OS << ">>"; break;
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case MCBinaryExpr::Sub: OS << '-'; break;
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case MCBinaryExpr::Xor: OS << '^'; break;
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}
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// Only print parens around the LHS if it is non-trivial.
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if (isa<MCConstantExpr>(BE.getRHS()) || isa<MCSymbolRefExpr>(BE.getRHS())) {
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OS << *BE.getRHS();
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} else {
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OS << '(' << *BE.getRHS() << ')';
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}
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return;
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}
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}
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assert(0 && "Invalid expression kind!");
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}
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void MCExpr::dump() const {
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print(dbgs());
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dbgs() << '\n';
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}
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/* *** */
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const MCBinaryExpr *MCBinaryExpr::Create(Opcode Opc, const MCExpr *LHS,
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const MCExpr *RHS, MCContext &Ctx) {
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return new (Ctx) MCBinaryExpr(Opc, LHS, RHS);
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}
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const MCUnaryExpr *MCUnaryExpr::Create(Opcode Opc, const MCExpr *Expr,
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MCContext &Ctx) {
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return new (Ctx) MCUnaryExpr(Opc, Expr);
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}
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const MCConstantExpr *MCConstantExpr::Create(int64_t Value, MCContext &Ctx) {
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return new (Ctx) MCConstantExpr(Value);
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}
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/* *** */
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const MCSymbolRefExpr *MCSymbolRefExpr::Create(const MCSymbol *Sym,
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VariantKind Kind,
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MCContext &Ctx) {
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return new (Ctx) MCSymbolRefExpr(Sym, Kind);
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}
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const MCSymbolRefExpr *MCSymbolRefExpr::Create(StringRef Name, VariantKind Kind,
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MCContext &Ctx) {
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return Create(Ctx.GetOrCreateSymbol(Name), Kind, Ctx);
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}
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StringRef MCSymbolRefExpr::getVariantKindName(VariantKind Kind) {
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switch (Kind) {
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default:
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case VK_Invalid: return "<<invalid>>";
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case VK_None: return "<<none>>";
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case VK_GOT: return "GOT";
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case VK_GOTOFF: return "GOTOFF";
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case VK_GOTPCREL: return "GOTPCREL";
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case VK_GOTTPOFF: return "GOTTPOFF";
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case VK_INDNTPOFF: return "INDNTPOFF";
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case VK_NTPOFF: return "NTPOFF";
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case VK_GOTNTPOFF: return "GOTNTPOFF";
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case VK_PLT: return "PLT";
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case VK_TLSGD: return "TLSGD";
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case VK_TLSLD: return "TLSLD";
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case VK_TLSLDM: return "TLSLDM";
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case VK_TPOFF: return "TPOFF";
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case VK_DTPOFF: return "DTPOFF";
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case VK_TLVP: return "TLVP";
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case VK_ARM_HI16: return ":upper16:";
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case VK_ARM_LO16: return ":lower16:";
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case VK_ARM_PLT: return "(PLT)";
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case VK_ARM_GOT: return "(GOT)";
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case VK_ARM_GOTOFF: return "(GOTOFF)";
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case VK_ARM_TPOFF: return "(tpoff)";
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case VK_ARM_GOTTPOFF: return "(gottpoff)";
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case VK_ARM_TLSGD: return "(tlsgd)";
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case VK_PPC_TOC: return "toc";
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case VK_PPC_HA16: return "ha16";
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case VK_PPC_LO16: return "lo16";
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}
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}
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MCSymbolRefExpr::VariantKind
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MCSymbolRefExpr::getVariantKindForName(StringRef Name) {
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return StringSwitch<VariantKind>(Name)
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.Case("GOT", VK_GOT)
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.Case("GOTOFF", VK_GOTOFF)
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.Case("GOTPCREL", VK_GOTPCREL)
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.Case("GOTTPOFF", VK_GOTTPOFF)
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.Case("INDNTPOFF", VK_INDNTPOFF)
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.Case("NTPOFF", VK_NTPOFF)
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.Case("GOTNTPOFF", VK_GOTNTPOFF)
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.Case("PLT", VK_PLT)
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.Case("TLSGD", VK_TLSGD)
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.Case("TLSLD", VK_TLSLD)
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.Case("TLSLDM", VK_TLSLDM)
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.Case("TPOFF", VK_TPOFF)
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.Case("DTPOFF", VK_DTPOFF)
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.Case("TLVP", VK_TLVP)
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.Default(VK_Invalid);
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}
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/* *** */
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void MCTargetExpr::Anchor() {}
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/* *** */
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bool MCExpr::EvaluateAsAbsolute(int64_t &Res) const {
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return EvaluateAsAbsolute(Res, 0, 0, 0);
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}
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bool MCExpr::EvaluateAsAbsolute(int64_t &Res,
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const MCAsmLayout &Layout) const {
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return EvaluateAsAbsolute(Res, &Layout.getAssembler(), &Layout, 0);
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}
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bool MCExpr::EvaluateAsAbsolute(int64_t &Res,
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const MCAsmLayout &Layout,
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const SectionAddrMap &Addrs) const {
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return EvaluateAsAbsolute(Res, &Layout.getAssembler(), &Layout, &Addrs);
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}
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bool MCExpr::EvaluateAsAbsolute(int64_t &Res, const MCAssembler &Asm) const {
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return EvaluateAsAbsolute(Res, &Asm, 0, 0);
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}
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bool MCExpr::EvaluateAsAbsolute(int64_t &Res, const MCAssembler *Asm,
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const MCAsmLayout *Layout,
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const SectionAddrMap *Addrs) const {
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MCValue Value;
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// Fast path constants.
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if (const MCConstantExpr *CE = dyn_cast<MCConstantExpr>(this)) {
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Res = CE->getValue();
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return true;
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}
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if (!EvaluateAsRelocatableImpl(Value, Asm, Layout, Addrs, Addrs) ||
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!Value.isAbsolute()) {
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// EvaluateAsAbsolute is defined to return the "current value" of
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// the expression if we are given a Layout object, even in cases
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// when the value is not fixed.
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if (Layout) {
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Res = Value.getConstant();
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if (Value.getSymA()) {
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Res += Layout->getSymbolOffset(
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&Layout->getAssembler().getSymbolData(Value.getSymA()->getSymbol()));
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}
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if (Value.getSymB()) {
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Res -= Layout->getSymbolOffset(
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&Layout->getAssembler().getSymbolData(Value.getSymB()->getSymbol()));
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}
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}
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return false;
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}
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Res = Value.getConstant();
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return true;
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}
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static bool EvaluateSymbolicAdd(const MCAssembler *Asm,
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const MCAsmLayout *Layout,
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const SectionAddrMap *Addrs,
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bool InSet,
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const MCValue &LHS,const MCSymbolRefExpr *RHS_A,
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const MCSymbolRefExpr *RHS_B, int64_t RHS_Cst,
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MCValue &Res) {
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// We can't add or subtract two symbols.
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if ((LHS.getSymA() && RHS_A) ||
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(LHS.getSymB() && RHS_B))
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return false;
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const MCSymbolRefExpr *A = LHS.getSymA() ? LHS.getSymA() : RHS_A;
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const MCSymbolRefExpr *B = LHS.getSymB() ? LHS.getSymB() : RHS_B;
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if (B) {
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// If we have a negated symbol, then we must have also have a non-negated
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// symbol in order to encode the expression. We can do this check later to
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// permit expressions which eventually fold to a representable form -- such
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// as (a + (0 - b)) -- if necessary.
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if (!A)
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return false;
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}
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// Absolutize symbol differences between defined symbols when we have a
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// layout object and the target requests it.
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assert(!(Layout && !Asm));
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if (Asm && A && B) {
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const MCSymbol &SA = A->getSymbol();
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const MCSymbol &SB = B->getSymbol();
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const MCObjectFormat &F = Asm->getBackend().getObjectFormat();
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if (SA.isDefined() && SB.isDefined() && F.isAbsolute(InSet, SA, SB)) {
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MCSymbolData &AD = Asm->getSymbolData(A->getSymbol());
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MCSymbolData &BD = Asm->getSymbolData(B->getSymbol());
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if (AD.getFragment() == BD.getFragment()) {
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Res = MCValue::get(+ AD.getOffset()
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- BD.getOffset()
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+ LHS.getConstant()
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+ RHS_Cst);
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return true;
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}
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if (Layout) {
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const MCSectionData &SecA = *AD.getFragment()->getParent();
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const MCSectionData &SecB = *BD.getFragment()->getParent();
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int64_t Val = + Layout->getSymbolOffset(&AD)
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- Layout->getSymbolOffset(&BD)
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+ LHS.getConstant()
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+ RHS_Cst;
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if (&SecA != &SecB) {
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if (!Addrs)
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return false;
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Val += Addrs->lookup(&SecA);
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Val -= Addrs->lookup(&SecB);
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}
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Res = MCValue::get(Val);
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return true;
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}
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}
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}
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Res = MCValue::get(A, B, LHS.getConstant() + RHS_Cst);
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return true;
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}
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bool MCExpr::EvaluateAsRelocatable(MCValue &Res,
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const MCAsmLayout *Layout) const {
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if (Layout)
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return EvaluateAsRelocatableImpl(Res, &Layout->getAssembler(), Layout,
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0, false);
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else
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return EvaluateAsRelocatableImpl(Res, 0, 0, 0, false);
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}
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bool MCExpr::EvaluateAsRelocatableImpl(MCValue &Res,
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const MCAssembler *Asm,
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const MCAsmLayout *Layout,
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const SectionAddrMap *Addrs,
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bool InSet) const {
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++stats::MCExprEvaluate;
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switch (getKind()) {
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case Target:
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return cast<MCTargetExpr>(this)->EvaluateAsRelocatableImpl(Res, Layout);
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case Constant:
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Res = MCValue::get(cast<MCConstantExpr>(this)->getValue());
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return true;
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case SymbolRef: {
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const MCSymbolRefExpr *SRE = cast<MCSymbolRefExpr>(this);
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const MCSymbol &Sym = SRE->getSymbol();
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// Evaluate recursively if this is a variable.
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if (Sym.isVariable() && SRE->getKind() == MCSymbolRefExpr::VK_None) {
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bool Ret = Sym.getVariableValue()->EvaluateAsRelocatableImpl(Res, Asm,
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Layout,
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Addrs,
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true);
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// If we failed to simplify this to a constant, let the target
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// handle it.
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if (Ret && !Res.getSymA() && !Res.getSymB())
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return true;
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}
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Res = MCValue::get(SRE, 0, 0);
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return true;
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}
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case Unary: {
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const MCUnaryExpr *AUE = cast<MCUnaryExpr>(this);
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MCValue Value;
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if (!AUE->getSubExpr()->EvaluateAsRelocatableImpl(Value, Asm, Layout,
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Addrs, InSet))
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return false;
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switch (AUE->getOpcode()) {
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case MCUnaryExpr::LNot:
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if (!Value.isAbsolute())
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return false;
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Res = MCValue::get(!Value.getConstant());
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break;
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case MCUnaryExpr::Minus:
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/// -(a - b + const) ==> (b - a - const)
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if (Value.getSymA() && !Value.getSymB())
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return false;
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Res = MCValue::get(Value.getSymB(), Value.getSymA(),
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-Value.getConstant());
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break;
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case MCUnaryExpr::Not:
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if (!Value.isAbsolute())
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return false;
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Res = MCValue::get(~Value.getConstant());
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break;
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case MCUnaryExpr::Plus:
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Res = Value;
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break;
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}
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return true;
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}
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case Binary: {
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const MCBinaryExpr *ABE = cast<MCBinaryExpr>(this);
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MCValue LHSValue, RHSValue;
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if (!ABE->getLHS()->EvaluateAsRelocatableImpl(LHSValue, Asm, Layout,
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Addrs, InSet) ||
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!ABE->getRHS()->EvaluateAsRelocatableImpl(RHSValue, Asm, Layout,
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Addrs, InSet))
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return false;
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// We only support a few operations on non-constant expressions, handle
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// those first.
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if (!LHSValue.isAbsolute() || !RHSValue.isAbsolute()) {
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switch (ABE->getOpcode()) {
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default:
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return false;
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case MCBinaryExpr::Sub:
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// Negate RHS and add.
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return EvaluateSymbolicAdd(Asm, Layout, Addrs, InSet, LHSValue,
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RHSValue.getSymB(), RHSValue.getSymA(),
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-RHSValue.getConstant(),
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Res);
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case MCBinaryExpr::Add:
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return EvaluateSymbolicAdd(Asm, Layout, Addrs, InSet, LHSValue,
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RHSValue.getSymA(), RHSValue.getSymB(),
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RHSValue.getConstant(),
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Res);
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}
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}
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// FIXME: We need target hooks for the evaluation. It may be limited in
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// width, and gas defines the result of comparisons and right shifts
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// differently from Apple as.
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int64_t LHS = LHSValue.getConstant(), RHS = RHSValue.getConstant();
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int64_t Result = 0;
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switch (ABE->getOpcode()) {
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case MCBinaryExpr::Add: Result = LHS + RHS; break;
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case MCBinaryExpr::And: Result = LHS & RHS; break;
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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;
|
|
}
|