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/MCObjectFormat.h"
18 #include "llvm/MC/MCSymbol.h"
19 #include "llvm/MC/MCValue.h"
20 #include "llvm/Support/Debug.h"
21 #include "llvm/Support/raw_ostream.h"
22 #include "llvm/Target/TargetAsmBackend.h"
27 STATISTIC(MCExprEvaluate, "Number of MCExpr evaluations");
31 void MCExpr::print(raw_ostream &OS) const {
34 return cast<MCTargetExpr>(this)->PrintImpl(OS);
35 case MCExpr::Constant:
36 OS << cast<MCConstantExpr>(*this).getValue();
39 case MCExpr::SymbolRef: {
40 const MCSymbolRefExpr &SRE = cast<MCSymbolRefExpr>(*this);
41 const MCSymbol &Sym = SRE.getSymbol();
43 if (SRE.getKind() == MCSymbolRefExpr::VK_ARM_HI16 ||
44 SRE.getKind() == MCSymbolRefExpr::VK_ARM_LO16)
45 OS << MCSymbolRefExpr::getVariantKindName(SRE.getKind());
47 // Parenthesize names that start with $ so that they don't look like
49 if (Sym.getName()[0] == '$')
50 OS << '(' << Sym << ')';
54 if (SRE.getKind() == MCSymbolRefExpr::VK_ARM_PLT ||
55 SRE.getKind() == MCSymbolRefExpr::VK_ARM_TLSGD ||
56 SRE.getKind() == MCSymbolRefExpr::VK_ARM_GOT ||
57 SRE.getKind() == MCSymbolRefExpr::VK_ARM_GOTOFF ||
58 SRE.getKind() == MCSymbolRefExpr::VK_ARM_TPOFF ||
59 SRE.getKind() == MCSymbolRefExpr::VK_ARM_GOTTPOFF)
60 OS << MCSymbolRefExpr::getVariantKindName(SRE.getKind());
61 else if (SRE.getKind() != MCSymbolRefExpr::VK_None &&
62 SRE.getKind() != MCSymbolRefExpr::VK_ARM_HI16 &&
63 SRE.getKind() != MCSymbolRefExpr::VK_ARM_LO16)
64 OS << '@' << MCSymbolRefExpr::getVariantKindName(SRE.getKind());
70 const MCUnaryExpr &UE = cast<MCUnaryExpr>(*this);
71 switch (UE.getOpcode()) {
72 default: assert(0 && "Invalid opcode!");
73 case MCUnaryExpr::LNot: OS << '!'; break;
74 case MCUnaryExpr::Minus: OS << '-'; break;
75 case MCUnaryExpr::Not: OS << '~'; break;
76 case MCUnaryExpr::Plus: OS << '+'; break;
78 OS << *UE.getSubExpr();
82 case MCExpr::Binary: {
83 const MCBinaryExpr &BE = cast<MCBinaryExpr>(*this);
85 // Only print parens around the LHS if it is non-trivial.
86 if (isa<MCConstantExpr>(BE.getLHS()) || isa<MCSymbolRefExpr>(BE.getLHS())) {
89 OS << '(' << *BE.getLHS() << ')';
92 switch (BE.getOpcode()) {
93 default: assert(0 && "Invalid opcode!");
94 case MCBinaryExpr::Add:
95 // Print "X-42" instead of "X+-42".
96 if (const MCConstantExpr *RHSC = dyn_cast<MCConstantExpr>(BE.getRHS())) {
97 if (RHSC->getValue() < 0) {
98 OS << RHSC->getValue();
105 case MCBinaryExpr::And: OS << '&'; break;
106 case MCBinaryExpr::Div: OS << '/'; break;
107 case MCBinaryExpr::EQ: OS << "=="; break;
108 case MCBinaryExpr::GT: OS << '>'; break;
109 case MCBinaryExpr::GTE: OS << ">="; break;
110 case MCBinaryExpr::LAnd: OS << "&&"; break;
111 case MCBinaryExpr::LOr: OS << "||"; break;
112 case MCBinaryExpr::LT: OS << '<'; break;
113 case MCBinaryExpr::LTE: OS << "<="; break;
114 case MCBinaryExpr::Mod: OS << '%'; break;
115 case MCBinaryExpr::Mul: OS << '*'; break;
116 case MCBinaryExpr::NE: OS << "!="; break;
117 case MCBinaryExpr::Or: OS << '|'; break;
118 case MCBinaryExpr::Shl: OS << "<<"; break;
119 case MCBinaryExpr::Shr: OS << ">>"; break;
120 case MCBinaryExpr::Sub: OS << '-'; break;
121 case MCBinaryExpr::Xor: OS << '^'; break;
124 // Only print parens around the LHS if it is non-trivial.
125 if (isa<MCConstantExpr>(BE.getRHS()) || isa<MCSymbolRefExpr>(BE.getRHS())) {
128 OS << '(' << *BE.getRHS() << ')';
134 assert(0 && "Invalid expression kind!");
137 void MCExpr::dump() const {
144 const MCBinaryExpr *MCBinaryExpr::Create(Opcode Opc, const MCExpr *LHS,
145 const MCExpr *RHS, MCContext &Ctx) {
146 return new (Ctx) MCBinaryExpr(Opc, LHS, RHS);
149 const MCUnaryExpr *MCUnaryExpr::Create(Opcode Opc, const MCExpr *Expr,
151 return new (Ctx) MCUnaryExpr(Opc, Expr);
154 const MCConstantExpr *MCConstantExpr::Create(int64_t Value, MCContext &Ctx) {
155 return new (Ctx) MCConstantExpr(Value);
160 const MCSymbolRefExpr *MCSymbolRefExpr::Create(const MCSymbol *Sym,
163 return new (Ctx) MCSymbolRefExpr(Sym, Kind);
166 const MCSymbolRefExpr *MCSymbolRefExpr::Create(StringRef Name, VariantKind Kind,
168 return Create(Ctx.GetOrCreateSymbol(Name), Kind, Ctx);
171 StringRef MCSymbolRefExpr::getVariantKindName(VariantKind Kind) {
174 case VK_Invalid: return "<<invalid>>";
175 case VK_None: return "<<none>>";
177 case VK_GOT: return "GOT";
178 case VK_GOTOFF: return "GOTOFF";
179 case VK_GOTPCREL: return "GOTPCREL";
180 case VK_GOTTPOFF: return "GOTTPOFF";
181 case VK_INDNTPOFF: return "INDNTPOFF";
182 case VK_NTPOFF: return "NTPOFF";
183 case VK_GOTNTPOFF: return "GOTNTPOFF";
184 case VK_PLT: return "PLT";
185 case VK_TLSGD: return "TLSGD";
186 case VK_TLSLD: return "TLSLD";
187 case VK_TLSLDM: return "TLSLDM";
188 case VK_TPOFF: return "TPOFF";
189 case VK_DTPOFF: return "DTPOFF";
190 case VK_TLVP: return "TLVP";
191 case VK_ARM_HI16: return ":upper16:";
192 case VK_ARM_LO16: return ":lower16:";
193 case VK_ARM_PLT: return "(PLT)";
194 case VK_ARM_GOT: return "(GOT)";
195 case VK_ARM_GOTOFF: return "(GOTOFF)";
196 case VK_ARM_TPOFF: return "(tpoff)";
197 case VK_ARM_GOTTPOFF: return "(gottpoff)";
198 case VK_ARM_TLSGD: return "(tldgd)";
199 case VK_PPC_TOC: return "toc";
203 MCSymbolRefExpr::VariantKind
204 MCSymbolRefExpr::getVariantKindForName(StringRef Name) {
205 return StringSwitch<VariantKind>(Name)
207 .Case("GOTOFF", VK_GOTOFF)
208 .Case("GOTPCREL", VK_GOTPCREL)
209 .Case("GOTTPOFF", VK_GOTTPOFF)
210 .Case("INDNTPOFF", VK_INDNTPOFF)
211 .Case("NTPOFF", VK_NTPOFF)
212 .Case("GOTNTPOFF", VK_GOTNTPOFF)
214 .Case("TLSGD", VK_TLSGD)
215 .Case("TLSLD", VK_TLSLD)
216 .Case("TLSLDM", VK_TLSLDM)
217 .Case("TPOFF", VK_TPOFF)
218 .Case("DTPOFF", VK_DTPOFF)
219 .Case("TLVP", VK_TLVP)
220 .Default(VK_Invalid);
225 void MCTargetExpr::Anchor() {}
229 bool MCExpr::EvaluateAsAbsolute(int64_t &Res, const MCAsmLayout *Layout) const {
232 // Fast path constants.
233 if (const MCConstantExpr *CE = dyn_cast<MCConstantExpr>(this)) {
234 Res = CE->getValue();
238 if (!EvaluateAsRelocatable(Value, Layout) || !Value.isAbsolute()) {
239 // EvaluateAsAbsolute is defined to return the "current value" of
240 // the expression if we are given a Layout object, even in cases
241 // when the value is not fixed.
243 Res = Value.getConstant();
244 if (Value.getSymA()) {
245 Res += Layout->getSymbolAddress(
246 &Layout->getAssembler().getSymbolData(Value.getSymA()->getSymbol()));
248 if (Value.getSymB()) {
249 Res -= Layout->getSymbolAddress(
250 &Layout->getAssembler().getSymbolData(Value.getSymB()->getSymbol()));
256 Res = Value.getConstant();
260 static bool EvaluateSymbolicAdd(const MCAsmLayout *Layout, bool InSet,
261 const MCValue &LHS,const MCSymbolRefExpr *RHS_A,
262 const MCSymbolRefExpr *RHS_B, int64_t RHS_Cst,
264 // We can't add or subtract two symbols.
265 if ((LHS.getSymA() && RHS_A) ||
266 (LHS.getSymB() && RHS_B))
269 const MCSymbolRefExpr *A = LHS.getSymA() ? LHS.getSymA() : RHS_A;
270 const MCSymbolRefExpr *B = LHS.getSymB() ? LHS.getSymB() : RHS_B;
272 // If we have a negated symbol, then we must have also have a non-negated
273 // symbol in order to encode the expression. We can do this check later to
274 // permit expressions which eventually fold to a representable form -- such
275 // as (a + (0 - b)) -- if necessary.
280 // Absolutize symbol differences between defined symbols when we have a
281 // layout object and the target requests it.
283 if (Layout && A && B) {
284 const MCSymbol &SA = A->getSymbol();
285 const MCSymbol &SB = B->getSymbol();
286 const MCObjectFormat &F =
287 Layout->getAssembler().getBackend().getObjectFormat();
288 if (SA.isDefined() && SB.isDefined() && F.isAbsolute(InSet, SA, SB)) {
289 const MCAssembler &Asm = Layout->getAssembler();
290 MCSymbolData &AD = Asm.getSymbolData(A->getSymbol());
291 MCSymbolData &BD = Asm.getSymbolData(B->getSymbol());
292 Res = MCValue::get(+ Layout->getSymbolAddress(&AD)
293 - Layout->getSymbolAddress(&BD)
301 Res = MCValue::get(A, B, LHS.getConstant() + RHS_Cst);
305 bool MCExpr::EvaluateAsRelocatable(MCValue &Res,
306 const MCAsmLayout *Layout) const {
307 return EvaluateAsRelocatableImpl(Res, Layout, false);
310 bool MCExpr::EvaluateAsRelocatableImpl(MCValue &Res,
311 const MCAsmLayout *Layout,
313 ++stats::MCExprEvaluate;
317 return cast<MCTargetExpr>(this)->EvaluateAsRelocatableImpl(Res, Layout);
320 Res = MCValue::get(cast<MCConstantExpr>(this)->getValue());
324 const MCSymbolRefExpr *SRE = cast<MCSymbolRefExpr>(this);
325 const MCSymbol &Sym = SRE->getSymbol();
327 // Evaluate recursively if this is a variable.
328 if (Sym.isVariable() && SRE->getKind() == MCSymbolRefExpr::VK_None)
329 return Sym.getVariableValue()->EvaluateAsRelocatableImpl(Res, Layout,
332 Res = MCValue::get(SRE, 0, 0);
337 const MCUnaryExpr *AUE = cast<MCUnaryExpr>(this);
340 if (!AUE->getSubExpr()->EvaluateAsRelocatableImpl(Value, Layout, InSet))
343 switch (AUE->getOpcode()) {
344 case MCUnaryExpr::LNot:
345 if (!Value.isAbsolute())
347 Res = MCValue::get(!Value.getConstant());
349 case MCUnaryExpr::Minus:
350 /// -(a - b + const) ==> (b - a - const)
351 if (Value.getSymA() && !Value.getSymB())
353 Res = MCValue::get(Value.getSymB(), Value.getSymA(),
354 -Value.getConstant());
356 case MCUnaryExpr::Not:
357 if (!Value.isAbsolute())
359 Res = MCValue::get(~Value.getConstant());
361 case MCUnaryExpr::Plus:
370 const MCBinaryExpr *ABE = cast<MCBinaryExpr>(this);
371 MCValue LHSValue, RHSValue;
373 if (!ABE->getLHS()->EvaluateAsRelocatableImpl(LHSValue, Layout, InSet) ||
374 !ABE->getRHS()->EvaluateAsRelocatableImpl(RHSValue, Layout, InSet))
377 // We only support a few operations on non-constant expressions, handle
379 if (!LHSValue.isAbsolute() || !RHSValue.isAbsolute()) {
380 switch (ABE->getOpcode()) {
383 case MCBinaryExpr::Sub:
384 // Negate RHS and add.
385 return EvaluateSymbolicAdd(Layout, InSet, LHSValue,
386 RHSValue.getSymB(), RHSValue.getSymA(),
387 -RHSValue.getConstant(),
390 case MCBinaryExpr::Add:
391 return EvaluateSymbolicAdd(Layout, InSet, LHSValue,
392 RHSValue.getSymA(), RHSValue.getSymB(),
393 RHSValue.getConstant(),
398 // FIXME: We need target hooks for the evaluation. It may be limited in
399 // width, and gas defines the result of comparisons and right shifts
400 // differently from Apple as.
401 int64_t LHS = LHSValue.getConstant(), RHS = RHSValue.getConstant();
403 switch (ABE->getOpcode()) {
404 case MCBinaryExpr::Add: Result = LHS + RHS; break;
405 case MCBinaryExpr::And: Result = LHS & RHS; break;
406 case MCBinaryExpr::Div: Result = LHS / RHS; break;
407 case MCBinaryExpr::EQ: Result = LHS == RHS; break;
408 case MCBinaryExpr::GT: Result = LHS > RHS; break;
409 case MCBinaryExpr::GTE: Result = LHS >= RHS; break;
410 case MCBinaryExpr::LAnd: Result = LHS && RHS; break;
411 case MCBinaryExpr::LOr: Result = LHS || RHS; break;
412 case MCBinaryExpr::LT: Result = LHS < RHS; break;
413 case MCBinaryExpr::LTE: Result = LHS <= RHS; break;
414 case MCBinaryExpr::Mod: Result = LHS % RHS; break;
415 case MCBinaryExpr::Mul: Result = LHS * RHS; break;
416 case MCBinaryExpr::NE: Result = LHS != RHS; break;
417 case MCBinaryExpr::Or: Result = LHS | RHS; break;
418 case MCBinaryExpr::Shl: Result = LHS << RHS; break;
419 case MCBinaryExpr::Shr: Result = LHS >> RHS; break;
420 case MCBinaryExpr::Sub: Result = LHS - RHS; break;
421 case MCBinaryExpr::Xor: Result = LHS ^ RHS; break;
424 Res = MCValue::get(Result);
429 assert(0 && "Invalid assembly expression kind!");