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 #define DEBUG_TYPE "mcexpr"
11 #include "llvm/MC/MCExpr.h"
12 #include "llvm/ADT/Statistic.h"
13 #include "llvm/ADT/StringSwitch.h"
14 #include "llvm/MC/MCAsmLayout.h"
15 #include "llvm/MC/MCAssembler.h"
16 #include "llvm/MC/MCContext.h"
17 #include "llvm/MC/MCSymbol.h"
18 #include "llvm/MC/MCValue.h"
19 #include "llvm/Support/Debug.h"
20 #include "llvm/Support/raw_ostream.h"
21 #include "llvm/Target/TargetAsmBackend.h"
26 STATISTIC(MCExprEvaluate, "Number of MCExpr evaluations");
30 void MCExpr::print(raw_ostream &OS) const {
33 return cast<MCTargetExpr>(this)->PrintImpl(OS);
34 case MCExpr::Constant:
35 OS << cast<MCConstantExpr>(*this).getValue();
38 case MCExpr::SymbolRef: {
39 const MCSymbolRefExpr &SRE = cast<MCSymbolRefExpr>(*this);
40 const MCSymbol &Sym = SRE.getSymbol();
42 if (SRE.getKind() == MCSymbolRefExpr::VK_ARM_HI16 ||
43 SRE.getKind() == MCSymbolRefExpr::VK_ARM_LO16)
44 OS << MCSymbolRefExpr::getVariantKindName(SRE.getKind());
46 // Parenthesize names that start with $ so that they don't look like
48 if (Sym.getName()[0] == '$')
49 OS << '(' << Sym << ')';
53 if (SRE.getKind() == MCSymbolRefExpr::VK_ARM_PLT)
54 OS << MCSymbolRefExpr::getVariantKindName(SRE.getKind());
55 else if (SRE.getKind() != MCSymbolRefExpr::VK_None &&
56 SRE.getKind() != MCSymbolRefExpr::VK_ARM_HI16 &&
57 SRE.getKind() != MCSymbolRefExpr::VK_ARM_LO16)
58 OS << '@' << MCSymbolRefExpr::getVariantKindName(SRE.getKind());
64 const MCUnaryExpr &UE = cast<MCUnaryExpr>(*this);
65 switch (UE.getOpcode()) {
66 default: assert(0 && "Invalid opcode!");
67 case MCUnaryExpr::LNot: OS << '!'; break;
68 case MCUnaryExpr::Minus: OS << '-'; break;
69 case MCUnaryExpr::Not: OS << '~'; break;
70 case MCUnaryExpr::Plus: OS << '+'; break;
72 OS << *UE.getSubExpr();
76 case MCExpr::Binary: {
77 const MCBinaryExpr &BE = cast<MCBinaryExpr>(*this);
79 // Only print parens around the LHS if it is non-trivial.
80 if (isa<MCConstantExpr>(BE.getLHS()) || isa<MCSymbolRefExpr>(BE.getLHS())) {
83 OS << '(' << *BE.getLHS() << ')';
86 switch (BE.getOpcode()) {
87 default: assert(0 && "Invalid opcode!");
88 case MCBinaryExpr::Add:
89 // Print "X-42" instead of "X+-42".
90 if (const MCConstantExpr *RHSC = dyn_cast<MCConstantExpr>(BE.getRHS())) {
91 if (RHSC->getValue() < 0) {
92 OS << RHSC->getValue();
99 case MCBinaryExpr::And: OS << '&'; break;
100 case MCBinaryExpr::Div: OS << '/'; break;
101 case MCBinaryExpr::EQ: OS << "=="; break;
102 case MCBinaryExpr::GT: OS << '>'; break;
103 case MCBinaryExpr::GTE: OS << ">="; break;
104 case MCBinaryExpr::LAnd: OS << "&&"; break;
105 case MCBinaryExpr::LOr: OS << "||"; break;
106 case MCBinaryExpr::LT: OS << '<'; break;
107 case MCBinaryExpr::LTE: OS << "<="; break;
108 case MCBinaryExpr::Mod: OS << '%'; break;
109 case MCBinaryExpr::Mul: OS << '*'; break;
110 case MCBinaryExpr::NE: OS << "!="; break;
111 case MCBinaryExpr::Or: OS << '|'; break;
112 case MCBinaryExpr::Shl: OS << "<<"; break;
113 case MCBinaryExpr::Shr: OS << ">>"; break;
114 case MCBinaryExpr::Sub: OS << '-'; break;
115 case MCBinaryExpr::Xor: OS << '^'; break;
118 // Only print parens around the LHS if it is non-trivial.
119 if (isa<MCConstantExpr>(BE.getRHS()) || isa<MCSymbolRefExpr>(BE.getRHS())) {
122 OS << '(' << *BE.getRHS() << ')';
128 assert(0 && "Invalid expression kind!");
131 void MCExpr::dump() const {
138 const MCBinaryExpr *MCBinaryExpr::Create(Opcode Opc, const MCExpr *LHS,
139 const MCExpr *RHS, MCContext &Ctx) {
140 return new (Ctx) MCBinaryExpr(Opc, LHS, RHS);
143 const MCUnaryExpr *MCUnaryExpr::Create(Opcode Opc, const MCExpr *Expr,
145 return new (Ctx) MCUnaryExpr(Opc, Expr);
148 const MCConstantExpr *MCConstantExpr::Create(int64_t Value, MCContext &Ctx) {
149 return new (Ctx) MCConstantExpr(Value);
154 const MCSymbolRefExpr *MCSymbolRefExpr::Create(const MCSymbol *Sym,
157 return new (Ctx) MCSymbolRefExpr(Sym, Kind);
160 const MCSymbolRefExpr *MCSymbolRefExpr::Create(StringRef Name, VariantKind Kind,
162 return Create(Ctx.GetOrCreateSymbol(Name), Kind, Ctx);
165 StringRef MCSymbolRefExpr::getVariantKindName(VariantKind Kind) {
168 case VK_Invalid: return "<<invalid>>";
169 case VK_None: return "<<none>>";
171 case VK_GOT: return "GOT";
172 case VK_GOTOFF: return "GOTOFF";
173 case VK_GOTPCREL: return "GOTPCREL";
174 case VK_GOTTPOFF: return "GOTTPOFF";
175 case VK_INDNTPOFF: return "INDNTPOFF";
176 case VK_NTPOFF: return "NTPOFF";
177 case VK_PLT: return "PLT";
178 case VK_TLSGD: return "TLSGD";
179 case VK_TPOFF: return "TPOFF";
180 case VK_ARM_HI16: return ":upper16:";
181 case VK_ARM_LO16: return ":lower16:";
182 case VK_ARM_PLT: return "(PLT)";
183 case VK_TLVP: return "TLVP";
187 MCSymbolRefExpr::VariantKind
188 MCSymbolRefExpr::getVariantKindForName(StringRef Name) {
189 return StringSwitch<VariantKind>(Name)
191 .Case("GOTOFF", VK_GOTOFF)
192 .Case("GOTPCREL", VK_GOTPCREL)
193 .Case("GOTTPOFF", VK_GOTTPOFF)
194 .Case("INDNTPOFF", VK_INDNTPOFF)
195 .Case("NTPOFF", VK_NTPOFF)
197 .Case("TLSGD", VK_TLSGD)
198 .Case("TPOFF", VK_TPOFF)
199 .Case("TLVP", VK_TLVP)
200 .Default(VK_Invalid);
205 void MCTargetExpr::Anchor() {}
209 bool MCExpr::EvaluateAsAbsolute(int64_t &Res, const MCAsmLayout *Layout) const {
212 // Fast path constants.
213 if (const MCConstantExpr *CE = dyn_cast<MCConstantExpr>(this)) {
214 Res = CE->getValue();
218 if (!EvaluateAsRelocatable(Value, Layout) || !Value.isAbsolute())
221 Res = Value.getConstant();
225 static bool EvaluateSymbolicAdd(const MCValue &LHS,const MCSymbolRefExpr *RHS_A,
226 const MCSymbolRefExpr *RHS_B, int64_t RHS_Cst,
228 // We can't add or subtract two symbols.
229 if ((LHS.getSymA() && RHS_A) ||
230 (LHS.getSymB() && RHS_B))
233 const MCSymbolRefExpr *A = LHS.getSymA() ? LHS.getSymA() : RHS_A;
234 const MCSymbolRefExpr *B = LHS.getSymB() ? LHS.getSymB() : RHS_B;
236 // If we have a negated symbol, then we must have also have a non-negated
237 // symbol in order to encode the expression. We can do this check later to
238 // permit expressions which eventually fold to a representable form -- such
239 // as (a + (0 - b)) -- if necessary.
243 Res = MCValue::get(A, B, LHS.getConstant() + RHS_Cst);
247 bool MCExpr::EvaluateAsRelocatable(MCValue &Res,
248 const MCAsmLayout *Layout) const {
249 ++stats::MCExprEvaluate;
253 return cast<MCTargetExpr>(this)->EvaluateAsRelocatableImpl(Res, Layout);
256 Res = MCValue::get(cast<MCConstantExpr>(this)->getValue());
260 const MCSymbolRefExpr *SRE = cast<MCSymbolRefExpr>(this);
261 const MCSymbol &Sym = SRE->getSymbol();
263 // Evaluate recursively if this is a variable.
264 if (Sym.isVariable()) {
265 if (!Sym.getVariableValue()->EvaluateAsRelocatable(Res, Layout))
268 // Absolutize symbol differences between defined symbols when we have a
269 // layout object and the target requests it.
270 if (Layout && Res.getSymB() &&
271 Layout->getAssembler().getBackend().hasAbsolutizedSet() &&
272 Res.getSymA()->getSymbol().isDefined() &&
273 Res.getSymB()->getSymbol().isDefined()) {
275 Layout->getAssembler().getSymbolData(Res.getSymA()->getSymbol());
277 Layout->getAssembler().getSymbolData(Res.getSymB()->getSymbol());
278 Res = MCValue::get(+ Layout->getSymbolAddress(&A)
279 - Layout->getSymbolAddress(&B)
280 + Res.getConstant());
286 Res = MCValue::get(SRE, 0, 0);
291 const MCUnaryExpr *AUE = cast<MCUnaryExpr>(this);
294 if (!AUE->getSubExpr()->EvaluateAsRelocatable(Value, Layout))
297 switch (AUE->getOpcode()) {
298 case MCUnaryExpr::LNot:
299 if (!Value.isAbsolute())
301 Res = MCValue::get(!Value.getConstant());
303 case MCUnaryExpr::Minus:
304 /// -(a - b + const) ==> (b - a - const)
305 if (Value.getSymA() && !Value.getSymB())
307 Res = MCValue::get(Value.getSymB(), Value.getSymA(),
308 -Value.getConstant());
310 case MCUnaryExpr::Not:
311 if (!Value.isAbsolute())
313 Res = MCValue::get(~Value.getConstant());
315 case MCUnaryExpr::Plus:
324 const MCBinaryExpr *ABE = cast<MCBinaryExpr>(this);
325 MCValue LHSValue, RHSValue;
327 if (!ABE->getLHS()->EvaluateAsRelocatable(LHSValue, Layout) ||
328 !ABE->getRHS()->EvaluateAsRelocatable(RHSValue, Layout))
331 // We only support a few operations on non-constant expressions, handle
333 if (!LHSValue.isAbsolute() || !RHSValue.isAbsolute()) {
334 switch (ABE->getOpcode()) {
337 case MCBinaryExpr::Sub:
338 // Negate RHS and add.
339 return EvaluateSymbolicAdd(LHSValue,
340 RHSValue.getSymB(), RHSValue.getSymA(),
341 -RHSValue.getConstant(),
344 case MCBinaryExpr::Add:
345 return EvaluateSymbolicAdd(LHSValue,
346 RHSValue.getSymA(), RHSValue.getSymB(),
347 RHSValue.getConstant(),
352 // FIXME: We need target hooks for the evaluation. It may be limited in
353 // width, and gas defines the result of comparisons and right shifts
354 // differently from Apple as.
355 int64_t LHS = LHSValue.getConstant(), RHS = RHSValue.getConstant();
357 switch (ABE->getOpcode()) {
358 case MCBinaryExpr::Add: Result = LHS + RHS; break;
359 case MCBinaryExpr::And: Result = LHS & RHS; break;
360 case MCBinaryExpr::Div: Result = LHS / RHS; break;
361 case MCBinaryExpr::EQ: Result = LHS == RHS; break;
362 case MCBinaryExpr::GT: Result = LHS > RHS; break;
363 case MCBinaryExpr::GTE: Result = LHS >= RHS; break;
364 case MCBinaryExpr::LAnd: Result = LHS && RHS; break;
365 case MCBinaryExpr::LOr: Result = LHS || RHS; break;
366 case MCBinaryExpr::LT: Result = LHS < RHS; break;
367 case MCBinaryExpr::LTE: Result = LHS <= RHS; break;
368 case MCBinaryExpr::Mod: Result = LHS % RHS; break;
369 case MCBinaryExpr::Mul: Result = LHS * RHS; break;
370 case MCBinaryExpr::NE: Result = LHS != RHS; break;
371 case MCBinaryExpr::Or: Result = LHS | RHS; break;
372 case MCBinaryExpr::Shl: Result = LHS << RHS; break;
373 case MCBinaryExpr::Shr: Result = LHS >> RHS; break;
374 case MCBinaryExpr::Sub: Result = LHS - RHS; break;
375 case MCBinaryExpr::Xor: Result = LHS ^ RHS; break;
378 Res = MCValue::get(Result);
383 assert(0 && "Invalid assembly expression kind!");