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/IR/InlineAsm.h"
15 #include "ConstantsContext.h"
16 #include "LLVMContextImpl.h"
17 #include "llvm/IR/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 /// Parse - Analyze the specified string (e.g. "==&{eax}") and fill in the
68 /// fields in this structure. If the constraint string is not understood,
69 /// return true, otherwise return false.
Parse(StringRef Str,InlineAsm::ConstraintInfoVector & ConstraintsSoFar)70 bool InlineAsm::ConstraintInfo::Parse(StringRef Str,
71 InlineAsm::ConstraintInfoVector &ConstraintsSoFar) {
72 StringRef::iterator I = Str.begin(), E = Str.end();
73 unsigned multipleAlternativeCount = Str.count('|') + 1;
74 unsigned multipleAlternativeIndex = 0;
75 ConstraintCodeVector *pCodes = &Codes;
76
77 // Initialize
78 isMultipleAlternative = (multipleAlternativeCount > 1 ? true : false);
79 if (isMultipleAlternative) {
80 multipleAlternatives.resize(multipleAlternativeCount);
81 pCodes = &multipleAlternatives[0].Codes;
82 }
83 Type = isInput;
84 isEarlyClobber = false;
85 MatchingInput = -1;
86 isCommutative = false;
87 isIndirect = false;
88 currentAlternativeIndex = 0;
89
90 // Parse prefixes.
91 if (*I == '~') {
92 Type = isClobber;
93 ++I;
94 } else if (*I == '=') {
95 ++I;
96 Type = isOutput;
97 }
98
99 if (*I == '*') {
100 isIndirect = true;
101 ++I;
102 }
103
104 if (I == E) return true; // Just a prefix, like "==" or "~".
105
106 // Parse the modifiers.
107 bool DoneWithModifiers = false;
108 while (!DoneWithModifiers) {
109 switch (*I) {
110 default:
111 DoneWithModifiers = true;
112 break;
113 case '&': // Early clobber.
114 if (Type != isOutput || // Cannot early clobber anything but output.
115 isEarlyClobber) // Reject &&&&&&
116 return true;
117 isEarlyClobber = true;
118 break;
119 case '%': // Commutative.
120 if (Type == isClobber || // Cannot commute clobbers.
121 isCommutative) // Reject %%%%%
122 return true;
123 isCommutative = true;
124 break;
125 case '#': // Comment.
126 case '*': // Register preferencing.
127 return true; // Not supported.
128 }
129
130 if (!DoneWithModifiers) {
131 ++I;
132 if (I == E) return true; // Just prefixes and modifiers!
133 }
134 }
135
136 // Parse the various constraints.
137 while (I != E) {
138 if (*I == '{') { // Physical register reference.
139 // Find the end of the register name.
140 StringRef::iterator ConstraintEnd = std::find(I+1, E, '}');
141 if (ConstraintEnd == E) return true; // "{foo"
142 pCodes->push_back(std::string(I, ConstraintEnd+1));
143 I = ConstraintEnd+1;
144 } else if (isdigit(static_cast<unsigned char>(*I))) { // Matching Constraint
145 // Maximal munch numbers.
146 StringRef::iterator NumStart = I;
147 while (I != E && isdigit(static_cast<unsigned char>(*I)))
148 ++I;
149 pCodes->push_back(std::string(NumStart, I));
150 unsigned N = atoi(pCodes->back().c_str());
151 // Check that this is a valid matching constraint!
152 if (N >= ConstraintsSoFar.size() || ConstraintsSoFar[N].Type != isOutput||
153 Type != isInput)
154 return true; // Invalid constraint number.
155
156 // If Operand N already has a matching input, reject this. An output
157 // can't be constrained to the same value as multiple inputs.
158 if (isMultipleAlternative) {
159 InlineAsm::SubConstraintInfo &scInfo =
160 ConstraintsSoFar[N].multipleAlternatives[multipleAlternativeIndex];
161 if (scInfo.MatchingInput != -1)
162 return true;
163 // Note that operand #n has a matching input.
164 scInfo.MatchingInput = ConstraintsSoFar.size();
165 } else {
166 if (ConstraintsSoFar[N].hasMatchingInput())
167 return true;
168 // Note that operand #n has a matching input.
169 ConstraintsSoFar[N].MatchingInput = ConstraintsSoFar.size();
170 }
171 } else if (*I == '|') {
172 multipleAlternativeIndex++;
173 pCodes = &multipleAlternatives[multipleAlternativeIndex].Codes;
174 ++I;
175 } else if (*I == '^') {
176 // Multi-letter constraint
177 // FIXME: For now assuming these are 2-character constraints.
178 pCodes->push_back(std::string(I+1, I+3));
179 I += 3;
180 } else {
181 // Single letter constraint.
182 pCodes->push_back(std::string(I, I+1));
183 ++I;
184 }
185 }
186
187 return false;
188 }
189
190 /// selectAlternative - Point this constraint to the alternative constraint
191 /// indicated by the index.
selectAlternative(unsigned index)192 void InlineAsm::ConstraintInfo::selectAlternative(unsigned index) {
193 if (index < multipleAlternatives.size()) {
194 currentAlternativeIndex = index;
195 InlineAsm::SubConstraintInfo &scInfo =
196 multipleAlternatives[currentAlternativeIndex];
197 MatchingInput = scInfo.MatchingInput;
198 Codes = scInfo.Codes;
199 }
200 }
201
202 InlineAsm::ConstraintInfoVector
ParseConstraints(StringRef Constraints)203 InlineAsm::ParseConstraints(StringRef Constraints) {
204 ConstraintInfoVector Result;
205
206 // Scan the constraints string.
207 for (StringRef::iterator I = Constraints.begin(),
208 E = Constraints.end(); I != E; ) {
209 ConstraintInfo Info;
210
211 // Find the end of this constraint.
212 StringRef::iterator ConstraintEnd = std::find(I, E, ',');
213
214 if (ConstraintEnd == I || // Empty constraint like ",,"
215 Info.Parse(StringRef(I, ConstraintEnd-I), Result)) {
216 Result.clear(); // Erroneous constraint?
217 break;
218 }
219
220 Result.push_back(Info);
221
222 // ConstraintEnd may be either the next comma or the end of the string. In
223 // the former case, we skip the comma.
224 I = ConstraintEnd;
225 if (I != E) {
226 ++I;
227 if (I == E) { Result.clear(); break; } // don't allow "xyz,"
228 }
229 }
230
231 return Result;
232 }
233
234 /// Verify - Verify that the specified constraint string is reasonable for the
235 /// specified function type, and otherwise validate the constraint string.
Verify(FunctionType * Ty,StringRef ConstStr)236 bool InlineAsm::Verify(FunctionType *Ty, StringRef ConstStr) {
237 if (Ty->isVarArg()) return false;
238
239 ConstraintInfoVector Constraints = ParseConstraints(ConstStr);
240
241 // Error parsing constraints.
242 if (Constraints.empty() && !ConstStr.empty()) return false;
243
244 unsigned NumOutputs = 0, NumInputs = 0, NumClobbers = 0;
245 unsigned NumIndirect = 0;
246
247 for (unsigned i = 0, e = Constraints.size(); i != e; ++i) {
248 switch (Constraints[i].Type) {
249 case InlineAsm::isOutput:
250 if ((NumInputs-NumIndirect) != 0 || NumClobbers != 0)
251 return false; // outputs before inputs and clobbers.
252 if (!Constraints[i].isIndirect) {
253 ++NumOutputs;
254 break;
255 }
256 ++NumIndirect;
257 // FALLTHROUGH for Indirect Outputs.
258 case InlineAsm::isInput:
259 if (NumClobbers) return false; // inputs before clobbers.
260 ++NumInputs;
261 break;
262 case InlineAsm::isClobber:
263 ++NumClobbers;
264 break;
265 }
266 }
267
268 switch (NumOutputs) {
269 case 0:
270 if (!Ty->getReturnType()->isVoidTy()) return false;
271 break;
272 case 1:
273 if (Ty->getReturnType()->isStructTy()) return false;
274 break;
275 default:
276 StructType *STy = dyn_cast<StructType>(Ty->getReturnType());
277 if (!STy || STy->getNumElements() != NumOutputs)
278 return false;
279 break;
280 }
281
282 if (Ty->getNumParams() != NumInputs) return false;
283 return true;
284 }
285
286