1 //===- InlineAsm.cpp - Implement the InlineAsm class ----------------------===//
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
9 // This file implements the InlineAsm class.
11 //===----------------------------------------------------------------------===//
13 #include "llvm/IR/InlineAsm.h"
14 #include "ConstantsContext.h"
15 #include "LLVMContextImpl.h"
16 #include "llvm/ADT/StringRef.h"
17 #include "llvm/IR/DerivedTypes.h"
18 #include "llvm/IR/LLVMContext.h"
19 #include "llvm/IR/Value.h"
20 #include "llvm/Support/Casting.h"
21 #include "llvm/Support/Compiler.h"
30 InlineAsm::InlineAsm(FunctionType *FTy, const std::string &asmString,
31 const std::string &constraints, bool hasSideEffects,
32 bool isAlignStack, AsmDialect asmDialect)
33 : Value(PointerType::getUnqual(FTy), Value::InlineAsmVal),
34 AsmString(asmString), Constraints(constraints), FTy(FTy),
35 HasSideEffects(hasSideEffects), IsAlignStack(isAlignStack),
37 // Do various checks on the constraint string and type.
38 assert(Verify(getFunctionType(), constraints) &&
39 "Function type not legal for constraints!");
42 InlineAsm *InlineAsm::get(FunctionType *FTy, StringRef AsmString,
43 StringRef Constraints, bool hasSideEffects,
44 bool isAlignStack, AsmDialect asmDialect) {
45 InlineAsmKeyType Key(AsmString, Constraints, FTy, hasSideEffects,
46 isAlignStack, asmDialect);
47 LLVMContextImpl *pImpl = FTy->getContext().pImpl;
48 return pImpl->InlineAsms.getOrCreate(PointerType::getUnqual(FTy), Key);
51 void InlineAsm::destroyConstant() {
52 getType()->getContext().pImpl->InlineAsms.remove(this);
56 FunctionType *InlineAsm::getFunctionType() const {
60 /// Parse - Analyze the specified string (e.g. "==&{eax}") and fill in the
61 /// fields in this structure. If the constraint string is not understood,
62 /// return true, otherwise return false.
63 bool InlineAsm::ConstraintInfo::Parse(StringRef Str,
64 InlineAsm::ConstraintInfoVector &ConstraintsSoFar) {
65 StringRef::iterator I = Str.begin(), E = Str.end();
66 unsigned multipleAlternativeCount = Str.count('|') + 1;
67 unsigned multipleAlternativeIndex = 0;
68 ConstraintCodeVector *pCodes = &Codes;
71 isMultipleAlternative = multipleAlternativeCount > 1;
72 if (isMultipleAlternative) {
73 multipleAlternatives.resize(multipleAlternativeCount);
74 pCodes = &multipleAlternatives[0].Codes;
77 isEarlyClobber = false;
79 isCommutative = false;
81 currentAlternativeIndex = 0;
88 // '{' must immediately follow '~'.
89 if (I != E && *I != '{')
91 } else if (*I == '=') {
101 if (I == E) return true; // Just a prefix, like "==" or "~".
103 // Parse the modifiers.
104 bool DoneWithModifiers = false;
105 while (!DoneWithModifiers) {
108 DoneWithModifiers = true;
110 case '&': // Early clobber.
111 if (Type != isOutput || // Cannot early clobber anything but output.
112 isEarlyClobber) // Reject &&&&&&
114 isEarlyClobber = true;
116 case '%': // Commutative.
117 if (Type == isClobber || // Cannot commute clobbers.
118 isCommutative) // Reject %%%%%
120 isCommutative = true;
122 case '#': // Comment.
123 case '*': // Register preferencing.
124 return true; // Not supported.
127 if (!DoneWithModifiers) {
129 if (I == E) return true; // Just prefixes and modifiers!
133 // Parse the various constraints.
135 if (*I == '{') { // Physical register reference.
136 // Find the end of the register name.
137 StringRef::iterator ConstraintEnd = std::find(I+1, E, '}');
138 if (ConstraintEnd == E) return true; // "{foo"
139 pCodes->push_back(std::string(StringRef(I, ConstraintEnd + 1 - I)));
141 } else if (isdigit(static_cast<unsigned char>(*I))) { // Matching Constraint
142 // Maximal munch numbers.
143 StringRef::iterator NumStart = I;
144 while (I != E && isdigit(static_cast<unsigned char>(*I)))
146 pCodes->push_back(std::string(StringRef(NumStart, I - NumStart)));
147 unsigned N = atoi(pCodes->back().c_str());
148 // Check that this is a valid matching constraint!
149 if (N >= ConstraintsSoFar.size() || ConstraintsSoFar[N].Type != isOutput||
151 return true; // Invalid constraint number.
153 // If Operand N already has a matching input, reject this. An output
154 // can't be constrained to the same value as multiple inputs.
155 if (isMultipleAlternative) {
156 if (multipleAlternativeIndex >=
157 ConstraintsSoFar[N].multipleAlternatives.size())
159 InlineAsm::SubConstraintInfo &scInfo =
160 ConstraintsSoFar[N].multipleAlternatives[multipleAlternativeIndex];
161 if (scInfo.MatchingInput != -1)
163 // Note that operand #n has a matching input.
164 scInfo.MatchingInput = ConstraintsSoFar.size();
165 assert(scInfo.MatchingInput >= 0);
167 if (ConstraintsSoFar[N].hasMatchingInput() &&
168 (size_t)ConstraintsSoFar[N].MatchingInput !=
169 ConstraintsSoFar.size())
171 // Note that operand #n has a matching input.
172 ConstraintsSoFar[N].MatchingInput = ConstraintsSoFar.size();
173 assert(ConstraintsSoFar[N].MatchingInput >= 0);
175 } else if (*I == '|') {
176 multipleAlternativeIndex++;
177 pCodes = &multipleAlternatives[multipleAlternativeIndex].Codes;
179 } else if (*I == '^') {
180 // Multi-letter constraint
181 // FIXME: For now assuming these are 2-character constraints.
182 pCodes->push_back(std::string(StringRef(I + 1, 2)));
184 } else if (*I == '@') {
185 // Multi-letter constraint
187 unsigned char C = static_cast<unsigned char>(*I);
188 assert(isdigit(C) && "Expected a digit!");
190 assert(N > 0 && "Found a zero letter constraint!");
192 pCodes->push_back(std::string(StringRef(I, N)));
195 // Single letter constraint.
196 pCodes->push_back(std::string(StringRef(I, 1)));
204 /// selectAlternative - Point this constraint to the alternative constraint
205 /// indicated by the index.
206 void InlineAsm::ConstraintInfo::selectAlternative(unsigned index) {
207 if (index < multipleAlternatives.size()) {
208 currentAlternativeIndex = index;
209 InlineAsm::SubConstraintInfo &scInfo =
210 multipleAlternatives[currentAlternativeIndex];
211 MatchingInput = scInfo.MatchingInput;
212 Codes = scInfo.Codes;
216 InlineAsm::ConstraintInfoVector
217 InlineAsm::ParseConstraints(StringRef Constraints) {
218 ConstraintInfoVector Result;
220 // Scan the constraints string.
221 for (StringRef::iterator I = Constraints.begin(),
222 E = Constraints.end(); I != E; ) {
225 // Find the end of this constraint.
226 StringRef::iterator ConstraintEnd = std::find(I, E, ',');
228 if (ConstraintEnd == I || // Empty constraint like ",,"
229 Info.Parse(StringRef(I, ConstraintEnd-I), Result)) {
230 Result.clear(); // Erroneous constraint?
234 Result.push_back(Info);
236 // ConstraintEnd may be either the next comma or the end of the string. In
237 // the former case, we skip the comma.
244 } // don't allow "xyz,"
251 /// Verify - Verify that the specified constraint string is reasonable for the
252 /// specified function type, and otherwise validate the constraint string.
253 bool InlineAsm::Verify(FunctionType *Ty, StringRef ConstStr) {
254 if (Ty->isVarArg()) return false;
256 ConstraintInfoVector Constraints = ParseConstraints(ConstStr);
258 // Error parsing constraints.
259 if (Constraints.empty() && !ConstStr.empty()) return false;
261 unsigned NumOutputs = 0, NumInputs = 0, NumClobbers = 0;
262 unsigned NumIndirect = 0;
264 for (unsigned i = 0, e = Constraints.size(); i != e; ++i) {
265 switch (Constraints[i].Type) {
266 case InlineAsm::isOutput:
267 if ((NumInputs-NumIndirect) != 0 || NumClobbers != 0)
268 return false; // outputs before inputs and clobbers.
269 if (!Constraints[i].isIndirect) {
274 LLVM_FALLTHROUGH; // We fall through for Indirect Outputs.
275 case InlineAsm::isInput:
276 if (NumClobbers) return false; // inputs before clobbers.
279 case InlineAsm::isClobber:
285 switch (NumOutputs) {
287 if (!Ty->getReturnType()->isVoidTy()) return false;
290 if (Ty->getReturnType()->isStructTy()) return false;
293 StructType *STy = dyn_cast<StructType>(Ty->getReturnType());
294 if (!STy || STy->getNumElements() != NumOutputs)
299 if (Ty->getNumParams() != NumInputs) return false;