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;
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
95 // '{' must immediately follow '~'.
96 if (I != E && *I != '{')
97 return true;
98 } else if (*I == '=') {
99 ++I;
100 Type = isOutput;
101 }
102
103 if (*I == '*') {
104 isIndirect = true;
105 ++I;
106 }
107
108 if (I == E) return true; // Just a prefix, like "==" or "~".
109
110 // Parse the modifiers.
111 bool DoneWithModifiers = false;
112 while (!DoneWithModifiers) {
113 switch (*I) {
114 default:
115 DoneWithModifiers = true;
116 break;
117 case '&': // Early clobber.
118 if (Type != isOutput || // Cannot early clobber anything but output.
119 isEarlyClobber) // Reject &&&&&&
120 return true;
121 isEarlyClobber = true;
122 break;
123 case '%': // Commutative.
124 if (Type == isClobber || // Cannot commute clobbers.
125 isCommutative) // Reject %%%%%
126 return true;
127 isCommutative = true;
128 break;
129 case '#': // Comment.
130 case '*': // Register preferencing.
131 return true; // Not supported.
132 }
133
134 if (!DoneWithModifiers) {
135 ++I;
136 if (I == E) return true; // Just prefixes and modifiers!
137 }
138 }
139
140 // Parse the various constraints.
141 while (I != E) {
142 if (*I == '{') { // Physical register reference.
143 // Find the end of the register name.
144 StringRef::iterator ConstraintEnd = std::find(I+1, E, '}');
145 if (ConstraintEnd == E) return true; // "{foo"
146 pCodes->push_back(std::string(I, ConstraintEnd+1));
147 I = ConstraintEnd+1;
148 } else if (isdigit(static_cast<unsigned char>(*I))) { // Matching Constraint
149 // Maximal munch numbers.
150 StringRef::iterator NumStart = I;
151 while (I != E && isdigit(static_cast<unsigned char>(*I)))
152 ++I;
153 pCodes->push_back(std::string(NumStart, I));
154 unsigned N = atoi(pCodes->back().c_str());
155 // Check that this is a valid matching constraint!
156 if (N >= ConstraintsSoFar.size() || ConstraintsSoFar[N].Type != isOutput||
157 Type != isInput)
158 return true; // Invalid constraint number.
159
160 // If Operand N already has a matching input, reject this. An output
161 // can't be constrained to the same value as multiple inputs.
162 if (isMultipleAlternative) {
163 InlineAsm::SubConstraintInfo &scInfo =
164 ConstraintsSoFar[N].multipleAlternatives[multipleAlternativeIndex];
165 if (scInfo.MatchingInput != -1)
166 return true;
167 // Note that operand #n has a matching input.
168 scInfo.MatchingInput = ConstraintsSoFar.size();
169 } else {
170 if (ConstraintsSoFar[N].hasMatchingInput() &&
171 (size_t)ConstraintsSoFar[N].MatchingInput !=
172 ConstraintsSoFar.size())
173 return true;
174 // Note that operand #n has a matching input.
175 ConstraintsSoFar[N].MatchingInput = ConstraintsSoFar.size();
176 }
177 } else if (*I == '|') {
178 multipleAlternativeIndex++;
179 pCodes = &multipleAlternatives[multipleAlternativeIndex].Codes;
180 ++I;
181 } else if (*I == '^') {
182 // Multi-letter constraint
183 // FIXME: For now assuming these are 2-character constraints.
184 pCodes->push_back(std::string(I+1, I+3));
185 I += 3;
186 } else {
187 // Single letter constraint.
188 pCodes->push_back(std::string(I, I+1));
189 ++I;
190 }
191 }
192
193 return false;
194 }
195
196 /// selectAlternative - Point this constraint to the alternative constraint
197 /// indicated by the index.
selectAlternative(unsigned index)198 void InlineAsm::ConstraintInfo::selectAlternative(unsigned index) {
199 if (index < multipleAlternatives.size()) {
200 currentAlternativeIndex = index;
201 InlineAsm::SubConstraintInfo &scInfo =
202 multipleAlternatives[currentAlternativeIndex];
203 MatchingInput = scInfo.MatchingInput;
204 Codes = scInfo.Codes;
205 }
206 }
207
208 InlineAsm::ConstraintInfoVector
ParseConstraints(StringRef Constraints)209 InlineAsm::ParseConstraints(StringRef Constraints) {
210 ConstraintInfoVector Result;
211
212 // Scan the constraints string.
213 for (StringRef::iterator I = Constraints.begin(),
214 E = Constraints.end(); I != E; ) {
215 ConstraintInfo Info;
216
217 // Find the end of this constraint.
218 StringRef::iterator ConstraintEnd = std::find(I, E, ',');
219
220 if (ConstraintEnd == I || // Empty constraint like ",,"
221 Info.Parse(StringRef(I, ConstraintEnd-I), Result)) {
222 Result.clear(); // Erroneous constraint?
223 break;
224 }
225
226 Result.push_back(Info);
227
228 // ConstraintEnd may be either the next comma or the end of the string. In
229 // the former case, we skip the comma.
230 I = ConstraintEnd;
231 if (I != E) {
232 ++I;
233 if (I == E) {
234 Result.clear();
235 break;
236 } // don't allow "xyz,"
237 }
238 }
239
240 return Result;
241 }
242
243 /// Verify - Verify that the specified constraint string is reasonable for the
244 /// specified function type, and otherwise validate the constraint string.
Verify(FunctionType * Ty,StringRef ConstStr)245 bool InlineAsm::Verify(FunctionType *Ty, StringRef ConstStr) {
246 if (Ty->isVarArg()) return false;
247
248 ConstraintInfoVector Constraints = ParseConstraints(ConstStr);
249
250 // Error parsing constraints.
251 if (Constraints.empty() && !ConstStr.empty()) return false;
252
253 unsigned NumOutputs = 0, NumInputs = 0, NumClobbers = 0;
254 unsigned NumIndirect = 0;
255
256 for (unsigned i = 0, e = Constraints.size(); i != e; ++i) {
257 switch (Constraints[i].Type) {
258 case InlineAsm::isOutput:
259 if ((NumInputs-NumIndirect) != 0 || NumClobbers != 0)
260 return false; // outputs before inputs and clobbers.
261 if (!Constraints[i].isIndirect) {
262 ++NumOutputs;
263 break;
264 }
265 ++NumIndirect;
266 // FALLTHROUGH for Indirect Outputs.
267 case InlineAsm::isInput:
268 if (NumClobbers) return false; // inputs before clobbers.
269 ++NumInputs;
270 break;
271 case InlineAsm::isClobber:
272 ++NumClobbers;
273 break;
274 }
275 }
276
277 switch (NumOutputs) {
278 case 0:
279 if (!Ty->getReturnType()->isVoidTy()) return false;
280 break;
281 case 1:
282 if (Ty->getReturnType()->isStructTy()) return false;
283 break;
284 default:
285 StructType *STy = dyn_cast<StructType>(Ty->getReturnType());
286 if (!STy || STy->getNumElements() != NumOutputs)
287 return false;
288 break;
289 }
290
291 if (Ty->getNumParams() != NumInputs) return false;
292 return true;
293 }
294
295