1 //===- MCExpr.cpp - Assembly Level Expression Implementation --------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #include "llvm/MC/MCExpr.h"
11 #include "llvm/ADT/StringSwitch.h"
12 #include "llvm/MC/MCAsmLayout.h"
13 #include "llvm/MC/MCAssembler.h"
14 #include "llvm/MC/MCContext.h"
15 #include "llvm/MC/MCSymbol.h"
16 #include "llvm/MC/MCValue.h"
17 #include "llvm/Support/Debug.h"
18 #include "llvm/Support/raw_ostream.h"
19 #include "llvm/Target/TargetAsmBackend.h"
22 void MCExpr::print(raw_ostream &OS) const {
25 return cast<MCTargetExpr>(this)->PrintImpl(OS);
26 case MCExpr::Constant:
27 OS << cast<MCConstantExpr>(*this).getValue();
30 case MCExpr::SymbolRef: {
31 const MCSymbolRefExpr &SRE = cast<MCSymbolRefExpr>(*this);
32 const MCSymbol &Sym = SRE.getSymbol();
34 // Parenthesize names that start with $ so that they don't look like
36 if (Sym.getName()[0] == '$')
37 OS << '(' << Sym << ')';
41 if (SRE.getKind() != MCSymbolRefExpr::VK_None)
42 OS << '@' << MCSymbolRefExpr::getVariantKindName(SRE.getKind());
48 const MCUnaryExpr &UE = cast<MCUnaryExpr>(*this);
49 switch (UE.getOpcode()) {
50 default: assert(0 && "Invalid opcode!");
51 case MCUnaryExpr::LNot: OS << '!'; break;
52 case MCUnaryExpr::Minus: OS << '-'; break;
53 case MCUnaryExpr::Not: OS << '~'; break;
54 case MCUnaryExpr::Plus: OS << '+'; break;
56 OS << *UE.getSubExpr();
60 case MCExpr::Binary: {
61 const MCBinaryExpr &BE = cast<MCBinaryExpr>(*this);
63 // Only print parens around the LHS if it is non-trivial.
64 if (isa<MCConstantExpr>(BE.getLHS()) || isa<MCSymbolRefExpr>(BE.getLHS())) {
67 OS << '(' << *BE.getLHS() << ')';
70 switch (BE.getOpcode()) {
71 default: assert(0 && "Invalid opcode!");
72 case MCBinaryExpr::Add:
73 // Print "X-42" instead of "X+-42".
74 if (const MCConstantExpr *RHSC = dyn_cast<MCConstantExpr>(BE.getRHS())) {
75 if (RHSC->getValue() < 0) {
76 OS << RHSC->getValue();
83 case MCBinaryExpr::And: OS << '&'; break;
84 case MCBinaryExpr::Div: OS << '/'; break;
85 case MCBinaryExpr::EQ: OS << "=="; break;
86 case MCBinaryExpr::GT: OS << '>'; break;
87 case MCBinaryExpr::GTE: OS << ">="; break;
88 case MCBinaryExpr::LAnd: OS << "&&"; break;
89 case MCBinaryExpr::LOr: OS << "||"; break;
90 case MCBinaryExpr::LT: OS << '<'; break;
91 case MCBinaryExpr::LTE: OS << "<="; break;
92 case MCBinaryExpr::Mod: OS << '%'; break;
93 case MCBinaryExpr::Mul: OS << '*'; break;
94 case MCBinaryExpr::NE: OS << "!="; break;
95 case MCBinaryExpr::Or: OS << '|'; break;
96 case MCBinaryExpr::Shl: OS << "<<"; break;
97 case MCBinaryExpr::Shr: OS << ">>"; break;
98 case MCBinaryExpr::Sub: OS << '-'; break;
99 case MCBinaryExpr::Xor: OS << '^'; break;
102 // Only print parens around the LHS if it is non-trivial.
103 if (isa<MCConstantExpr>(BE.getRHS()) || isa<MCSymbolRefExpr>(BE.getRHS())) {
106 OS << '(' << *BE.getRHS() << ')';
112 assert(0 && "Invalid expression kind!");
115 void MCExpr::dump() const {
122 const MCBinaryExpr *MCBinaryExpr::Create(Opcode Opc, const MCExpr *LHS,
123 const MCExpr *RHS, MCContext &Ctx) {
124 return new (Ctx) MCBinaryExpr(Opc, LHS, RHS);
127 const MCUnaryExpr *MCUnaryExpr::Create(Opcode Opc, const MCExpr *Expr,
129 return new (Ctx) MCUnaryExpr(Opc, Expr);
132 const MCConstantExpr *MCConstantExpr::Create(int64_t Value, MCContext &Ctx) {
133 return new (Ctx) MCConstantExpr(Value);
138 const MCSymbolRefExpr *MCSymbolRefExpr::Create(const MCSymbol *Sym,
141 return new (Ctx) MCSymbolRefExpr(Sym, Kind);
144 const MCSymbolRefExpr *MCSymbolRefExpr::Create(StringRef Name, VariantKind Kind,
146 return Create(Ctx.GetOrCreateSymbol(Name), Kind, Ctx);
149 const MCSymbolRefExpr *MCSymbolRefExpr::CreateTemp(StringRef Name,
152 return Create(Ctx.GetOrCreateTemporarySymbol(Name), Kind, Ctx);
155 StringRef MCSymbolRefExpr::getVariantKindName(VariantKind Kind) {
158 case VK_Invalid: return "<<invalid>>";
159 case VK_None: return "<<none>>";
161 case VK_GOT: return "GOT";
162 case VK_GOTOFF: return "GOTOFF";
163 case VK_GOTPCREL: return "GOTPCREL";
164 case VK_GOTTPOFF: return "GOTTPOFF";
165 case VK_INDNTPOFF: return "INDNTPOFF";
166 case VK_NTPOFF: return "NTPOFF";
167 case VK_PLT: return "PLT";
168 case VK_TLSGD: return "TLSGD";
169 case VK_TPOFF: return "TPOFF";
173 MCSymbolRefExpr::VariantKind
174 MCSymbolRefExpr::getVariantKindForName(StringRef Name) {
175 return StringSwitch<VariantKind>(Name)
177 .Case("GOTOFF", VK_GOTOFF)
178 .Case("GOTPCREL", VK_GOTPCREL)
179 .Case("GOTTPOFF", VK_GOTTPOFF)
180 .Case("INDNTPOFF", VK_INDNTPOFF)
181 .Case("NTPOFF", VK_NTPOFF)
183 .Case("TLSGD", VK_TLSGD)
184 .Case("TPOFF", VK_TPOFF)
185 .Default(VK_Invalid);
190 void MCTargetExpr::Anchor() {}
194 bool MCExpr::EvaluateAsAbsolute(int64_t &Res, const MCAsmLayout *Layout) const {
197 if (!EvaluateAsRelocatable(Value, Layout) || !Value.isAbsolute())
200 Res = Value.getConstant();
204 static bool EvaluateSymbolicAdd(const MCValue &LHS, const MCSymbol *RHS_A,
205 const MCSymbol *RHS_B, int64_t RHS_Cst,
207 // We can't add or subtract two symbols.
208 if ((LHS.getSymA() && RHS_A) ||
209 (LHS.getSymB() && RHS_B))
212 const MCSymbol *A = LHS.getSymA() ? LHS.getSymA() : RHS_A;
213 const MCSymbol *B = LHS.getSymB() ? LHS.getSymB() : RHS_B;
215 // If we have a negated symbol, then we must have also have a non-negated
216 // symbol in order to encode the expression. We can do this check later to
217 // permit expressions which eventually fold to a representable form -- such
218 // as (a + (0 - b)) -- if necessary.
222 Res = MCValue::get(A, B, LHS.getConstant() + RHS_Cst);
226 bool MCExpr::EvaluateAsRelocatable(MCValue &Res,
227 const MCAsmLayout *Layout) const {
230 return cast<MCTargetExpr>(this)->EvaluateAsRelocatableImpl(Res, Layout);
233 Res = MCValue::get(cast<MCConstantExpr>(this)->getValue());
237 const MCSymbol &Sym = cast<MCSymbolRefExpr>(this)->getSymbol();
239 // Evaluate recursively if this is a variable.
240 if (Sym.isVariable()) {
241 if (!Sym.getValue()->EvaluateAsRelocatable(Res, Layout))
244 // Absolutize symbol differences between defined symbols when we have a
245 // layout object and the target requests it.
246 if (Layout && Res.getSymB() &&
247 Layout->getAssembler().getBackend().hasAbsolutizedSet() &&
248 Res.getSymA()->isDefined() && Res.getSymB()->isDefined()) {
249 MCSymbolData &A = Layout->getAssembler().getSymbolData(*Res.getSymA());
250 MCSymbolData &B = Layout->getAssembler().getSymbolData(*Res.getSymB());
251 Res = MCValue::get(+ A.getFragment()->getAddress() + A.getOffset()
252 - B.getFragment()->getAddress() - B.getOffset()
253 + Res.getConstant());
259 Res = MCValue::get(&Sym, 0, 0);
264 const MCUnaryExpr *AUE = cast<MCUnaryExpr>(this);
267 if (!AUE->getSubExpr()->EvaluateAsRelocatable(Value, Layout))
270 switch (AUE->getOpcode()) {
271 case MCUnaryExpr::LNot:
272 if (!Value.isAbsolute())
274 Res = MCValue::get(!Value.getConstant());
276 case MCUnaryExpr::Minus:
277 /// -(a - b + const) ==> (b - a - const)
278 if (Value.getSymA() && !Value.getSymB())
280 Res = MCValue::get(Value.getSymB(), Value.getSymA(),
281 -Value.getConstant());
283 case MCUnaryExpr::Not:
284 if (!Value.isAbsolute())
286 Res = MCValue::get(~Value.getConstant());
288 case MCUnaryExpr::Plus:
297 const MCBinaryExpr *ABE = cast<MCBinaryExpr>(this);
298 MCValue LHSValue, RHSValue;
300 if (!ABE->getLHS()->EvaluateAsRelocatable(LHSValue, Layout) ||
301 !ABE->getRHS()->EvaluateAsRelocatable(RHSValue, Layout))
304 // We only support a few operations on non-constant expressions, handle
306 if (!LHSValue.isAbsolute() || !RHSValue.isAbsolute()) {
307 switch (ABE->getOpcode()) {
310 case MCBinaryExpr::Sub:
311 // Negate RHS and add.
312 return EvaluateSymbolicAdd(LHSValue,
313 RHSValue.getSymB(), RHSValue.getSymA(),
314 -RHSValue.getConstant(),
317 case MCBinaryExpr::Add:
318 return EvaluateSymbolicAdd(LHSValue,
319 RHSValue.getSymA(), RHSValue.getSymB(),
320 RHSValue.getConstant(),
325 // FIXME: We need target hooks for the evaluation. It may be limited in
326 // width, and gas defines the result of comparisons and right shifts
327 // differently from Apple as.
328 int64_t LHS = LHSValue.getConstant(), RHS = RHSValue.getConstant();
330 switch (ABE->getOpcode()) {
331 case MCBinaryExpr::Add: Result = LHS + RHS; break;
332 case MCBinaryExpr::And: Result = LHS & RHS; break;
333 case MCBinaryExpr::Div: Result = LHS / RHS; break;
334 case MCBinaryExpr::EQ: Result = LHS == RHS; break;
335 case MCBinaryExpr::GT: Result = LHS > RHS; break;
336 case MCBinaryExpr::GTE: Result = LHS >= RHS; break;
337 case MCBinaryExpr::LAnd: Result = LHS && RHS; break;
338 case MCBinaryExpr::LOr: Result = LHS || RHS; break;
339 case MCBinaryExpr::LT: Result = LHS < RHS; break;
340 case MCBinaryExpr::LTE: Result = LHS <= RHS; break;
341 case MCBinaryExpr::Mod: Result = LHS % RHS; break;
342 case MCBinaryExpr::Mul: Result = LHS * RHS; break;
343 case MCBinaryExpr::NE: Result = LHS != RHS; break;
344 case MCBinaryExpr::Or: Result = LHS | RHS; break;
345 case MCBinaryExpr::Shl: Result = LHS << RHS; break;
346 case MCBinaryExpr::Shr: Result = LHS >> RHS; break;
347 case MCBinaryExpr::Sub: Result = LHS - RHS; break;
348 case MCBinaryExpr::Xor: Result = LHS ^ RHS; break;
351 Res = MCValue::get(Result);
356 assert(0 && "Invalid assembly expression kind!");