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 // Parenthesize names that start with $ so that they don't look like
44 if (Sym.getName()[0] == '$')
45 OS << '(' << Sym << ')';
49 if (SRE.getKind() != MCSymbolRefExpr::VK_None)
50 OS << '@' << MCSymbolRefExpr::getVariantKindName(SRE.getKind());
56 const MCUnaryExpr &UE = cast<MCUnaryExpr>(*this);
57 switch (UE.getOpcode()) {
58 default: assert(0 && "Invalid opcode!");
59 case MCUnaryExpr::LNot: OS << '!'; break;
60 case MCUnaryExpr::Minus: OS << '-'; break;
61 case MCUnaryExpr::Not: OS << '~'; break;
62 case MCUnaryExpr::Plus: OS << '+'; break;
64 OS << *UE.getSubExpr();
68 case MCExpr::Binary: {
69 const MCBinaryExpr &BE = cast<MCBinaryExpr>(*this);
71 // Only print parens around the LHS if it is non-trivial.
72 if (isa<MCConstantExpr>(BE.getLHS()) || isa<MCSymbolRefExpr>(BE.getLHS())) {
75 OS << '(' << *BE.getLHS() << ')';
78 switch (BE.getOpcode()) {
79 default: assert(0 && "Invalid opcode!");
80 case MCBinaryExpr::Add:
81 // Print "X-42" instead of "X+-42".
82 if (const MCConstantExpr *RHSC = dyn_cast<MCConstantExpr>(BE.getRHS())) {
83 if (RHSC->getValue() < 0) {
84 OS << RHSC->getValue();
91 case MCBinaryExpr::And: OS << '&'; break;
92 case MCBinaryExpr::Div: OS << '/'; break;
93 case MCBinaryExpr::EQ: OS << "=="; break;
94 case MCBinaryExpr::GT: OS << '>'; break;
95 case MCBinaryExpr::GTE: OS << ">="; break;
96 case MCBinaryExpr::LAnd: OS << "&&"; break;
97 case MCBinaryExpr::LOr: OS << "||"; break;
98 case MCBinaryExpr::LT: OS << '<'; break;
99 case MCBinaryExpr::LTE: OS << "<="; break;
100 case MCBinaryExpr::Mod: OS << '%'; break;
101 case MCBinaryExpr::Mul: OS << '*'; break;
102 case MCBinaryExpr::NE: OS << "!="; break;
103 case MCBinaryExpr::Or: OS << '|'; break;
104 case MCBinaryExpr::Shl: OS << "<<"; break;
105 case MCBinaryExpr::Shr: OS << ">>"; break;
106 case MCBinaryExpr::Sub: OS << '-'; break;
107 case MCBinaryExpr::Xor: OS << '^'; break;
110 // Only print parens around the LHS if it is non-trivial.
111 if (isa<MCConstantExpr>(BE.getRHS()) || isa<MCSymbolRefExpr>(BE.getRHS())) {
114 OS << '(' << *BE.getRHS() << ')';
120 assert(0 && "Invalid expression kind!");
123 void MCExpr::dump() const {
130 const MCBinaryExpr *MCBinaryExpr::Create(Opcode Opc, const MCExpr *LHS,
131 const MCExpr *RHS, MCContext &Ctx) {
132 return new (Ctx) MCBinaryExpr(Opc, LHS, RHS);
135 const MCUnaryExpr *MCUnaryExpr::Create(Opcode Opc, const MCExpr *Expr,
137 return new (Ctx) MCUnaryExpr(Opc, Expr);
140 const MCConstantExpr *MCConstantExpr::Create(int64_t Value, MCContext &Ctx) {
141 return new (Ctx) MCConstantExpr(Value);
146 const MCSymbolRefExpr *MCSymbolRefExpr::Create(const MCSymbol *Sym,
149 return new (Ctx) MCSymbolRefExpr(Sym, Kind);
152 const MCSymbolRefExpr *MCSymbolRefExpr::Create(StringRef Name, VariantKind Kind,
154 return Create(Ctx.GetOrCreateSymbol(Name), Kind, Ctx);
157 StringRef MCSymbolRefExpr::getVariantKindName(VariantKind Kind) {
160 case VK_Invalid: return "<<invalid>>";
161 case VK_None: return "<<none>>";
163 case VK_GOT: return "GOT";
164 case VK_GOTOFF: return "GOTOFF";
165 case VK_GOTPCREL: return "GOTPCREL";
166 case VK_GOTTPOFF: return "GOTTPOFF";
167 case VK_INDNTPOFF: return "INDNTPOFF";
168 case VK_NTPOFF: return "NTPOFF";
169 case VK_PLT: return "PLT";
170 case VK_TLSGD: return "TLSGD";
171 case VK_TPOFF: return "TPOFF";
175 MCSymbolRefExpr::VariantKind
176 MCSymbolRefExpr::getVariantKindForName(StringRef Name) {
177 return StringSwitch<VariantKind>(Name)
179 .Case("GOTOFF", VK_GOTOFF)
180 .Case("GOTPCREL", VK_GOTPCREL)
181 .Case("GOTTPOFF", VK_GOTTPOFF)
182 .Case("INDNTPOFF", VK_INDNTPOFF)
183 .Case("NTPOFF", VK_NTPOFF)
185 .Case("TLSGD", VK_TLSGD)
186 .Case("TPOFF", VK_TPOFF)
187 .Default(VK_Invalid);
192 void MCTargetExpr::Anchor() {}
196 bool MCExpr::EvaluateAsAbsolute(int64_t &Res, const MCAsmLayout *Layout) const {
199 // Fast path constants.
200 if (const MCConstantExpr *CE = dyn_cast<MCConstantExpr>(this)) {
201 Res = CE->getValue();
205 if (!EvaluateAsRelocatable(Value, Layout) || !Value.isAbsolute())
208 Res = Value.getConstant();
212 static bool EvaluateSymbolicAdd(const MCValue &LHS,const MCSymbolRefExpr *RHS_A,
213 const MCSymbolRefExpr *RHS_B, int64_t RHS_Cst,
215 // We can't add or subtract two symbols.
216 if ((LHS.getSymA() && RHS_A) ||
217 (LHS.getSymB() && RHS_B))
220 const MCSymbolRefExpr *A = LHS.getSymA() ? LHS.getSymA() : RHS_A;
221 const MCSymbolRefExpr *B = LHS.getSymB() ? LHS.getSymB() : RHS_B;
223 // If we have a negated symbol, then we must have also have a non-negated
224 // symbol in order to encode the expression. We can do this check later to
225 // permit expressions which eventually fold to a representable form -- such
226 // as (a + (0 - b)) -- if necessary.
230 Res = MCValue::get(A, B, LHS.getConstant() + RHS_Cst);
234 bool MCExpr::EvaluateAsRelocatable(MCValue &Res,
235 const MCAsmLayout *Layout) const {
236 ++stats::MCExprEvaluate;
240 return cast<MCTargetExpr>(this)->EvaluateAsRelocatableImpl(Res, Layout);
243 Res = MCValue::get(cast<MCConstantExpr>(this)->getValue());
247 const MCSymbolRefExpr *SRE = cast<MCSymbolRefExpr>(this);
248 const MCSymbol &Sym = SRE->getSymbol();
250 // Evaluate recursively if this is a variable.
251 if (Sym.isVariable()) {
252 if (!Sym.getValue()->EvaluateAsRelocatable(Res, Layout))
255 // Absolutize symbol differences between defined symbols when we have a
256 // layout object and the target requests it.
257 if (Layout && Res.getSymB() &&
258 Layout->getAssembler().getBackend().hasAbsolutizedSet() &&
259 Res.getSymA()->getSymbol().isDefined() &&
260 Res.getSymB()->getSymbol().isDefined()) {
262 Layout->getAssembler().getSymbolData(Res.getSymA()->getSymbol());
264 Layout->getAssembler().getSymbolData(Res.getSymB()->getSymbol());
265 Res = MCValue::get(+ Layout->getSymbolAddress(&A)
266 - Layout->getSymbolAddress(&B)
267 + Res.getConstant());
273 Res = MCValue::get(SRE, 0, 0);
278 const MCUnaryExpr *AUE = cast<MCUnaryExpr>(this);
281 if (!AUE->getSubExpr()->EvaluateAsRelocatable(Value, Layout))
284 switch (AUE->getOpcode()) {
285 case MCUnaryExpr::LNot:
286 if (!Value.isAbsolute())
288 Res = MCValue::get(!Value.getConstant());
290 case MCUnaryExpr::Minus:
291 /// -(a - b + const) ==> (b - a - const)
292 if (Value.getSymA() && !Value.getSymB())
294 Res = MCValue::get(Value.getSymB(), Value.getSymA(),
295 -Value.getConstant());
297 case MCUnaryExpr::Not:
298 if (!Value.isAbsolute())
300 Res = MCValue::get(~Value.getConstant());
302 case MCUnaryExpr::Plus:
311 const MCBinaryExpr *ABE = cast<MCBinaryExpr>(this);
312 MCValue LHSValue, RHSValue;
314 if (!ABE->getLHS()->EvaluateAsRelocatable(LHSValue, Layout) ||
315 !ABE->getRHS()->EvaluateAsRelocatable(RHSValue, Layout))
318 // We only support a few operations on non-constant expressions, handle
320 if (!LHSValue.isAbsolute() || !RHSValue.isAbsolute()) {
321 switch (ABE->getOpcode()) {
324 case MCBinaryExpr::Sub:
325 // Negate RHS and add.
326 return EvaluateSymbolicAdd(LHSValue,
327 RHSValue.getSymB(), RHSValue.getSymA(),
328 -RHSValue.getConstant(),
331 case MCBinaryExpr::Add:
332 return EvaluateSymbolicAdd(LHSValue,
333 RHSValue.getSymA(), RHSValue.getSymB(),
334 RHSValue.getConstant(),
339 // FIXME: We need target hooks for the evaluation. It may be limited in
340 // width, and gas defines the result of comparisons and right shifts
341 // differently from Apple as.
342 int64_t LHS = LHSValue.getConstant(), RHS = RHSValue.getConstant();
344 switch (ABE->getOpcode()) {
345 case MCBinaryExpr::Add: Result = LHS + RHS; break;
346 case MCBinaryExpr::And: Result = LHS & RHS; break;
347 case MCBinaryExpr::Div: Result = LHS / RHS; break;
348 case MCBinaryExpr::EQ: Result = LHS == RHS; break;
349 case MCBinaryExpr::GT: Result = LHS > RHS; break;
350 case MCBinaryExpr::GTE: Result = LHS >= RHS; break;
351 case MCBinaryExpr::LAnd: Result = LHS && RHS; break;
352 case MCBinaryExpr::LOr: Result = LHS || RHS; break;
353 case MCBinaryExpr::LT: Result = LHS < RHS; break;
354 case MCBinaryExpr::LTE: Result = LHS <= RHS; break;
355 case MCBinaryExpr::Mod: Result = LHS % RHS; break;
356 case MCBinaryExpr::Mul: Result = LHS * RHS; break;
357 case MCBinaryExpr::NE: Result = LHS != RHS; break;
358 case MCBinaryExpr::Or: Result = LHS | RHS; break;
359 case MCBinaryExpr::Shl: Result = LHS << RHS; break;
360 case MCBinaryExpr::Shr: Result = LHS >> RHS; break;
361 case MCBinaryExpr::Sub: Result = LHS - RHS; break;
362 case MCBinaryExpr::Xor: Result = LHS ^ RHS; break;
365 Res = MCValue::get(Result);
370 assert(0 && "Invalid assembly expression kind!");