302 lines
9.6 KiB
C++
302 lines
9.6 KiB
C++
//===- InlineAsm.cpp - Implement the InlineAsm class ----------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the InlineAsm class.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/IR/InlineAsm.h"
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#include "ConstantsContext.h"
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#include "LLVMContextImpl.h"
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#include "llvm/ADT/StringRef.h"
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#include "llvm/IR/DerivedTypes.h"
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#include "llvm/IR/LLVMContext.h"
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#include "llvm/IR/Value.h"
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#include "llvm/Support/Casting.h"
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#include "llvm/Support/Compiler.h"
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#include <algorithm>
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#include <cassert>
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#include <cctype>
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#include <cstddef>
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#include <cstdlib>
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using namespace llvm;
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InlineAsm::InlineAsm(FunctionType *FTy, const std::string &asmString,
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const std::string &constraints, bool hasSideEffects,
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bool isAlignStack, AsmDialect asmDialect)
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: Value(PointerType::getUnqual(FTy), Value::InlineAsmVal),
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AsmString(asmString), Constraints(constraints), FTy(FTy),
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HasSideEffects(hasSideEffects), IsAlignStack(isAlignStack),
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Dialect(asmDialect) {
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// Do various checks on the constraint string and type.
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assert(Verify(getFunctionType(), constraints) &&
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"Function type not legal for constraints!");
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}
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InlineAsm *InlineAsm::get(FunctionType *FTy, StringRef AsmString,
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StringRef Constraints, bool hasSideEffects,
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bool isAlignStack, AsmDialect asmDialect) {
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InlineAsmKeyType Key(AsmString, Constraints, FTy, hasSideEffects,
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isAlignStack, asmDialect);
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LLVMContextImpl *pImpl = FTy->getContext().pImpl;
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return pImpl->InlineAsms.getOrCreate(PointerType::getUnqual(FTy), Key);
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}
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void InlineAsm::destroyConstant() {
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getType()->getContext().pImpl->InlineAsms.remove(this);
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delete this;
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}
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FunctionType *InlineAsm::getFunctionType() const {
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return FTy;
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}
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/// Parse - Analyze the specified string (e.g. "==&{eax}") and fill in the
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/// fields in this structure. If the constraint string is not understood,
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/// return true, otherwise return false.
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bool InlineAsm::ConstraintInfo::Parse(StringRef Str,
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InlineAsm::ConstraintInfoVector &ConstraintsSoFar) {
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StringRef::iterator I = Str.begin(), E = Str.end();
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unsigned multipleAlternativeCount = Str.count('|') + 1;
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unsigned multipleAlternativeIndex = 0;
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ConstraintCodeVector *pCodes = &Codes;
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// Initialize
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isMultipleAlternative = multipleAlternativeCount > 1;
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if (isMultipleAlternative) {
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multipleAlternatives.resize(multipleAlternativeCount);
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pCodes = &multipleAlternatives[0].Codes;
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}
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Type = isInput;
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isEarlyClobber = false;
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MatchingInput = -1;
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isCommutative = false;
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isIndirect = false;
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currentAlternativeIndex = 0;
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// Parse prefixes.
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if (*I == '~') {
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Type = isClobber;
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++I;
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// '{' must immediately follow '~'.
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if (I != E && *I != '{')
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return true;
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} else if (*I == '=') {
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++I;
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Type = isOutput;
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}
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if (*I == '*') {
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isIndirect = true;
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++I;
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}
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if (I == E) return true; // Just a prefix, like "==" or "~".
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// Parse the modifiers.
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bool DoneWithModifiers = false;
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while (!DoneWithModifiers) {
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switch (*I) {
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default:
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DoneWithModifiers = true;
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break;
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case '&': // Early clobber.
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if (Type != isOutput || // Cannot early clobber anything but output.
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isEarlyClobber) // Reject &&&&&&
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return true;
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isEarlyClobber = true;
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break;
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case '%': // Commutative.
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if (Type == isClobber || // Cannot commute clobbers.
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isCommutative) // Reject %%%%%
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return true;
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isCommutative = true;
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break;
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case '#': // Comment.
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case '*': // Register preferencing.
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return true; // Not supported.
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}
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if (!DoneWithModifiers) {
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++I;
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if (I == E) return true; // Just prefixes and modifiers!
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}
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}
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// Parse the various constraints.
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while (I != E) {
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if (*I == '{') { // Physical register reference.
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// Find the end of the register name.
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StringRef::iterator ConstraintEnd = std::find(I+1, E, '}');
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if (ConstraintEnd == E) return true; // "{foo"
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pCodes->push_back(std::string(StringRef(I, ConstraintEnd + 1 - I)));
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I = ConstraintEnd+1;
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} else if (isdigit(static_cast<unsigned char>(*I))) { // Matching Constraint
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// Maximal munch numbers.
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StringRef::iterator NumStart = I;
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while (I != E && isdigit(static_cast<unsigned char>(*I)))
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++I;
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pCodes->push_back(std::string(StringRef(NumStart, I - NumStart)));
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unsigned N = atoi(pCodes->back().c_str());
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// Check that this is a valid matching constraint!
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if (N >= ConstraintsSoFar.size() || ConstraintsSoFar[N].Type != isOutput||
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Type != isInput)
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return true; // Invalid constraint number.
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// If Operand N already has a matching input, reject this. An output
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// can't be constrained to the same value as multiple inputs.
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if (isMultipleAlternative) {
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if (multipleAlternativeIndex >=
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ConstraintsSoFar[N].multipleAlternatives.size())
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return true;
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InlineAsm::SubConstraintInfo &scInfo =
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ConstraintsSoFar[N].multipleAlternatives[multipleAlternativeIndex];
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if (scInfo.MatchingInput != -1)
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return true;
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// Note that operand #n has a matching input.
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scInfo.MatchingInput = ConstraintsSoFar.size();
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assert(scInfo.MatchingInput >= 0);
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} else {
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if (ConstraintsSoFar[N].hasMatchingInput() &&
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(size_t)ConstraintsSoFar[N].MatchingInput !=
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ConstraintsSoFar.size())
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return true;
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// Note that operand #n has a matching input.
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ConstraintsSoFar[N].MatchingInput = ConstraintsSoFar.size();
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assert(ConstraintsSoFar[N].MatchingInput >= 0);
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}
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} else if (*I == '|') {
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multipleAlternativeIndex++;
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pCodes = &multipleAlternatives[multipleAlternativeIndex].Codes;
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++I;
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} else if (*I == '^') {
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// Multi-letter constraint
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// FIXME: For now assuming these are 2-character constraints.
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pCodes->push_back(std::string(StringRef(I + 1, 2)));
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I += 3;
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} else if (*I == '@') {
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// Multi-letter constraint
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++I;
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unsigned char C = static_cast<unsigned char>(*I);
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assert(isdigit(C) && "Expected a digit!");
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int N = C - '0';
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assert(N > 0 && "Found a zero letter constraint!");
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++I;
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pCodes->push_back(std::string(StringRef(I, N)));
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I += N;
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} else {
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// Single letter constraint.
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pCodes->push_back(std::string(StringRef(I, 1)));
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++I;
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}
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}
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return false;
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}
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/// selectAlternative - Point this constraint to the alternative constraint
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/// indicated by the index.
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void InlineAsm::ConstraintInfo::selectAlternative(unsigned index) {
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if (index < multipleAlternatives.size()) {
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currentAlternativeIndex = index;
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InlineAsm::SubConstraintInfo &scInfo =
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multipleAlternatives[currentAlternativeIndex];
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MatchingInput = scInfo.MatchingInput;
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Codes = scInfo.Codes;
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}
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}
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InlineAsm::ConstraintInfoVector
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InlineAsm::ParseConstraints(StringRef Constraints) {
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ConstraintInfoVector Result;
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// Scan the constraints string.
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for (StringRef::iterator I = Constraints.begin(),
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E = Constraints.end(); I != E; ) {
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ConstraintInfo Info;
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// Find the end of this constraint.
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StringRef::iterator ConstraintEnd = std::find(I, E, ',');
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if (ConstraintEnd == I || // Empty constraint like ",,"
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Info.Parse(StringRef(I, ConstraintEnd-I), Result)) {
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Result.clear(); // Erroneous constraint?
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break;
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}
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Result.push_back(Info);
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// ConstraintEnd may be either the next comma or the end of the string. In
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// the former case, we skip the comma.
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I = ConstraintEnd;
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if (I != E) {
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++I;
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if (I == E) {
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Result.clear();
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break;
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} // don't allow "xyz,"
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}
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}
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return Result;
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}
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/// Verify - Verify that the specified constraint string is reasonable for the
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/// specified function type, and otherwise validate the constraint string.
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bool InlineAsm::Verify(FunctionType *Ty, StringRef ConstStr) {
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if (Ty->isVarArg()) return false;
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ConstraintInfoVector Constraints = ParseConstraints(ConstStr);
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// Error parsing constraints.
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if (Constraints.empty() && !ConstStr.empty()) return false;
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unsigned NumOutputs = 0, NumInputs = 0, NumClobbers = 0;
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unsigned NumIndirect = 0;
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for (unsigned i = 0, e = Constraints.size(); i != e; ++i) {
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switch (Constraints[i].Type) {
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case InlineAsm::isOutput:
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if ((NumInputs-NumIndirect) != 0 || NumClobbers != 0)
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return false; // outputs before inputs and clobbers.
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if (!Constraints[i].isIndirect) {
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++NumOutputs;
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break;
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}
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++NumIndirect;
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LLVM_FALLTHROUGH; // We fall through for Indirect Outputs.
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case InlineAsm::isInput:
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if (NumClobbers) return false; // inputs before clobbers.
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++NumInputs;
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break;
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case InlineAsm::isClobber:
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++NumClobbers;
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break;
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}
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}
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switch (NumOutputs) {
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case 0:
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if (!Ty->getReturnType()->isVoidTy()) return false;
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break;
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case 1:
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if (Ty->getReturnType()->isStructTy()) return false;
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break;
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default:
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StructType *STy = dyn_cast<StructType>(Ty->getReturnType());
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if (!STy || STy->getNumElements() != NumOutputs)
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return false;
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break;
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}
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if (Ty->getNumParams() != NumInputs) return false;
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return true;
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}
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