1 //===-- InlineAsm.cpp - Implement the InlineAsm class ---------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements the InlineAsm class.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "llvm/InlineAsm.h"
15 #include "ConstantsContext.h"
16 #include "LLVMContextImpl.h"
17 #include "llvm/DerivedTypes.h"
18 #include <algorithm>
19 #include <cctype>
20 using namespace llvm;
21
22 // Implement the first virtual method in this class in this file so the
23 // InlineAsm vtable is emitted here.
~InlineAsm()24 InlineAsm::~InlineAsm() {
25 }
26
27
get(FunctionType * Ty,StringRef AsmString,StringRef Constraints,bool hasSideEffects,bool isAlignStack,AsmDialect asmDialect)28 InlineAsm *InlineAsm::get(FunctionType *Ty, StringRef AsmString,
29 StringRef Constraints, bool hasSideEffects,
30 bool isAlignStack, AsmDialect asmDialect) {
31 InlineAsmKeyType Key(AsmString, Constraints, hasSideEffects, isAlignStack,
32 asmDialect);
33 LLVMContextImpl *pImpl = Ty->getContext().pImpl;
34 return pImpl->InlineAsms.getOrCreate(PointerType::getUnqual(Ty), Key);
35 }
36
InlineAsm(PointerType * Ty,const std::string & asmString,const std::string & constraints,bool hasSideEffects,bool isAlignStack,AsmDialect asmDialect)37 InlineAsm::InlineAsm(PointerType *Ty, const std::string &asmString,
38 const std::string &constraints, bool hasSideEffects,
39 bool isAlignStack, AsmDialect asmDialect)
40 : Value(Ty, Value::InlineAsmVal),
41 AsmString(asmString), Constraints(constraints),
42 HasSideEffects(hasSideEffects), IsAlignStack(isAlignStack),
43 Dialect(asmDialect) {
44
45 // Do various checks on the constraint string and type.
46 assert(Verify(getFunctionType(), constraints) &&
47 "Function type not legal for constraints!");
48 }
49
destroyConstant()50 void InlineAsm::destroyConstant() {
51 getType()->getContext().pImpl->InlineAsms.remove(this);
52 delete this;
53 }
54
getFunctionType() const55 FunctionType *InlineAsm::getFunctionType() const {
56 return cast<FunctionType>(getType()->getElementType());
57 }
58
59 ///Default constructor.
ConstraintInfo()60 InlineAsm::ConstraintInfo::ConstraintInfo() :
61 Type(isInput), isEarlyClobber(false),
62 MatchingInput(-1), isCommutative(false),
63 isIndirect(false), isMultipleAlternative(false),
64 currentAlternativeIndex(0) {
65 }
66
67 /// Copy constructor.
ConstraintInfo(const ConstraintInfo & other)68 InlineAsm::ConstraintInfo::ConstraintInfo(const ConstraintInfo &other) :
69 Type(other.Type), isEarlyClobber(other.isEarlyClobber),
70 MatchingInput(other.MatchingInput), isCommutative(other.isCommutative),
71 isIndirect(other.isIndirect), Codes(other.Codes),
72 isMultipleAlternative(other.isMultipleAlternative),
73 multipleAlternatives(other.multipleAlternatives),
74 currentAlternativeIndex(other.currentAlternativeIndex) {
75 }
76
77 /// Parse - Analyze the specified string (e.g. "==&{eax}") and fill in the
78 /// fields in this structure. If the constraint string is not understood,
79 /// return true, otherwise return false.
Parse(StringRef Str,InlineAsm::ConstraintInfoVector & ConstraintsSoFar)80 bool InlineAsm::ConstraintInfo::Parse(StringRef Str,
81 InlineAsm::ConstraintInfoVector &ConstraintsSoFar) {
82 StringRef::iterator I = Str.begin(), E = Str.end();
83 unsigned multipleAlternativeCount = Str.count('|') + 1;
84 unsigned multipleAlternativeIndex = 0;
85 ConstraintCodeVector *pCodes = &Codes;
86
87 // Initialize
88 isMultipleAlternative = (multipleAlternativeCount > 1 ? true : false);
89 if (isMultipleAlternative) {
90 multipleAlternatives.resize(multipleAlternativeCount);
91 pCodes = &multipleAlternatives[0].Codes;
92 }
93 Type = isInput;
94 isEarlyClobber = false;
95 MatchingInput = -1;
96 isCommutative = false;
97 isIndirect = false;
98 currentAlternativeIndex = 0;
99
100 // Parse prefixes.
101 if (*I == '~') {
102 Type = isClobber;
103 ++I;
104 } else if (*I == '=') {
105 ++I;
106 Type = isOutput;
107 }
108
109 if (*I == '*') {
110 isIndirect = true;
111 ++I;
112 }
113
114 if (I == E) return true; // Just a prefix, like "==" or "~".
115
116 // Parse the modifiers.
117 bool DoneWithModifiers = false;
118 while (!DoneWithModifiers) {
119 switch (*I) {
120 default:
121 DoneWithModifiers = true;
122 break;
123 case '&': // Early clobber.
124 if (Type != isOutput || // Cannot early clobber anything but output.
125 isEarlyClobber) // Reject &&&&&&
126 return true;
127 isEarlyClobber = true;
128 break;
129 case '%': // Commutative.
130 if (Type == isClobber || // Cannot commute clobbers.
131 isCommutative) // Reject %%%%%
132 return true;
133 isCommutative = true;
134 break;
135 case '#': // Comment.
136 case '*': // Register preferencing.
137 return true; // Not supported.
138 }
139
140 if (!DoneWithModifiers) {
141 ++I;
142 if (I == E) return true; // Just prefixes and modifiers!
143 }
144 }
145
146 // Parse the various constraints.
147 while (I != E) {
148 if (*I == '{') { // Physical register reference.
149 // Find the end of the register name.
150 StringRef::iterator ConstraintEnd = std::find(I+1, E, '}');
151 if (ConstraintEnd == E) return true; // "{foo"
152 pCodes->push_back(std::string(I, ConstraintEnd+1));
153 I = ConstraintEnd+1;
154 } else if (isdigit(*I)) { // Matching Constraint
155 // Maximal munch numbers.
156 StringRef::iterator NumStart = I;
157 while (I != E && isdigit(*I))
158 ++I;
159 pCodes->push_back(std::string(NumStart, I));
160 unsigned N = atoi(pCodes->back().c_str());
161 // Check that this is a valid matching constraint!
162 if (N >= ConstraintsSoFar.size() || ConstraintsSoFar[N].Type != isOutput||
163 Type != isInput)
164 return true; // Invalid constraint number.
165
166 // If Operand N already has a matching input, reject this. An output
167 // can't be constrained to the same value as multiple inputs.
168 if (isMultipleAlternative) {
169 InlineAsm::SubConstraintInfo &scInfo =
170 ConstraintsSoFar[N].multipleAlternatives[multipleAlternativeIndex];
171 if (scInfo.MatchingInput != -1)
172 return true;
173 // Note that operand #n has a matching input.
174 scInfo.MatchingInput = ConstraintsSoFar.size();
175 } else {
176 if (ConstraintsSoFar[N].hasMatchingInput())
177 return true;
178 // Note that operand #n has a matching input.
179 ConstraintsSoFar[N].MatchingInput = ConstraintsSoFar.size();
180 }
181 } else if (*I == '|') {
182 multipleAlternativeIndex++;
183 pCodes = &multipleAlternatives[multipleAlternativeIndex].Codes;
184 ++I;
185 } else if (*I == '^') {
186 // Multi-letter constraint
187 // FIXME: For now assuming these are 2-character constraints.
188 pCodes->push_back(std::string(I+1, I+3));
189 I += 3;
190 } else {
191 // Single letter constraint.
192 pCodes->push_back(std::string(I, I+1));
193 ++I;
194 }
195 }
196
197 return false;
198 }
199
200 /// selectAlternative - Point this constraint to the alternative constraint
201 /// indicated by the index.
selectAlternative(unsigned index)202 void InlineAsm::ConstraintInfo::selectAlternative(unsigned index) {
203 if (index < multipleAlternatives.size()) {
204 currentAlternativeIndex = index;
205 InlineAsm::SubConstraintInfo &scInfo =
206 multipleAlternatives[currentAlternativeIndex];
207 MatchingInput = scInfo.MatchingInput;
208 Codes = scInfo.Codes;
209 }
210 }
211
212 InlineAsm::ConstraintInfoVector
ParseConstraints(StringRef Constraints)213 InlineAsm::ParseConstraints(StringRef Constraints) {
214 ConstraintInfoVector Result;
215
216 // Scan the constraints string.
217 for (StringRef::iterator I = Constraints.begin(),
218 E = Constraints.end(); I != E; ) {
219 ConstraintInfo Info;
220
221 // Find the end of this constraint.
222 StringRef::iterator ConstraintEnd = std::find(I, E, ',');
223
224 if (ConstraintEnd == I || // Empty constraint like ",,"
225 Info.Parse(StringRef(I, ConstraintEnd-I), Result)) {
226 Result.clear(); // Erroneous constraint?
227 break;
228 }
229
230 Result.push_back(Info);
231
232 // ConstraintEnd may be either the next comma or the end of the string. In
233 // the former case, we skip the comma.
234 I = ConstraintEnd;
235 if (I != E) {
236 ++I;
237 if (I == E) { Result.clear(); break; } // don't allow "xyz,"
238 }
239 }
240
241 return Result;
242 }
243
244 /// Verify - Verify that the specified constraint string is reasonable for the
245 /// specified function type, and otherwise validate the constraint string.
Verify(FunctionType * Ty,StringRef ConstStr)246 bool InlineAsm::Verify(FunctionType *Ty, StringRef ConstStr) {
247 if (Ty->isVarArg()) return false;
248
249 ConstraintInfoVector Constraints = ParseConstraints(ConstStr);
250
251 // Error parsing constraints.
252 if (Constraints.empty() && !ConstStr.empty()) return false;
253
254 unsigned NumOutputs = 0, NumInputs = 0, NumClobbers = 0;
255 unsigned NumIndirect = 0;
256
257 for (unsigned i = 0, e = Constraints.size(); i != e; ++i) {
258 switch (Constraints[i].Type) {
259 case InlineAsm::isOutput:
260 if ((NumInputs-NumIndirect) != 0 || NumClobbers != 0)
261 return false; // outputs before inputs and clobbers.
262 if (!Constraints[i].isIndirect) {
263 ++NumOutputs;
264 break;
265 }
266 ++NumIndirect;
267 // FALLTHROUGH for Indirect Outputs.
268 case InlineAsm::isInput:
269 if (NumClobbers) return false; // inputs before clobbers.
270 ++NumInputs;
271 break;
272 case InlineAsm::isClobber:
273 ++NumClobbers;
274 break;
275 }
276 }
277
278 switch (NumOutputs) {
279 case 0:
280 if (!Ty->getReturnType()->isVoidTy()) return false;
281 break;
282 case 1:
283 if (Ty->getReturnType()->isStructTy()) return false;
284 break;
285 default:
286 StructType *STy = dyn_cast<StructType>(Ty->getReturnType());
287 if (STy == 0 || STy->getNumElements() != NumOutputs)
288 return false;
289 break;
290 }
291
292 if (Ty->getNumParams() != NumInputs) return false;
293 return true;
294 }
295
296