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//===-- InlineAsm.cpp - Implement the InlineAsm class ---------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Chris Lattner and is distributed under the
// University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the InlineAsm class.
//
//===----------------------------------------------------------------------===//
#include "llvm/InlineAsm.h"
#include "llvm/DerivedTypes.h"
#include <algorithm>
#include <cctype>
using namespace llvm;
// NOTE: when memoizing the function type, we have to be careful to handle the
// case when the type gets refined.
InlineAsm *InlineAsm::get(const FunctionType *Ty, const std::string &AsmString,
const std::string &Constraints, bool hasSideEffects) {
// FIXME: memoize!
return new InlineAsm(Ty, AsmString, Constraints, hasSideEffects);
}
InlineAsm::InlineAsm(const FunctionType *Ty, const std::string &asmString,
const std::string &constraints, bool hasSideEffects)
: Value(PointerType::get(Ty), Value::InlineAsmVal), AsmString(asmString),
Constraints(constraints), HasSideEffects(hasSideEffects) {
// Do various checks on the constraint string and type.
assert(Verify(Ty, constraints) && "Function type not legal for constraints!");
}
const FunctionType *InlineAsm::getFunctionType() const {
return cast<FunctionType>(getType()->getElementType());
}
/// Parse - Analyze the specified string (e.g. "==&{eax}") and fill in the
/// fields in this structure. If the constraint string is not understood,
/// return true, otherwise return false.
bool InlineAsm::ConstraintInfo::Parse(const std::string &Str,
std::vector<InlineAsm::ConstraintInfo> &ConstraintsSoFar) {
std::string::const_iterator I = Str.begin(), E = Str.end();
// Initialize
Type = isInput;
isEarlyClobber = false;
isIndirectOutput = false;
hasMatchingInput = false;
isCommutative = false;
// Parse the prefix.
if (*I == '~') {
Type = isClobber;
++I;
} else if (*I == '=') {
++I;
Type = isOutput;
if (I != E && *I == '=') {
isIndirectOutput = true;
++I;
}
}
if (I == E) return true; // Just a prefix, like "==" or "~".
// Parse the modifiers.
bool DoneWithModifiers = false;
while (!DoneWithModifiers) {
switch (*I) {
default:
DoneWithModifiers = true;
break;
case '&': // Early clobber.
if (Type != isOutput || // Cannot early clobber anything but output.
isEarlyClobber) // Reject &&&&&&
return true;
isEarlyClobber = true;
break;
case '%': // Commutative.
if (Type == isClobber || // Cannot commute clobbers.
isCommutative) // Reject %%%%%
return true;
isCommutative = true;
break;
case '#': // Comment.
case '*': // Register preferencing.
return true; // Not supported.
}
if (!DoneWithModifiers) {
++I;
if (I == E) return true; // Just prefixes and modifiers!
}
}
// Parse the various constraints.
while (I != E) {
if (*I == '{') { // Physical register reference.
// Find the end of the register name.
std::string::const_iterator ConstraintEnd = std::find(I+1, E, '}');
if (ConstraintEnd == E) return true; // "{foo"
Codes.push_back(std::string(I, ConstraintEnd+1));
I = ConstraintEnd+1;
} else if (isdigit(*I)) { // Matching Constraint
// Maximal munch numbers.
std::string::const_iterator NumStart = I;
while (I != E && isdigit(*I))
++I;
Codes.push_back(std::string(NumStart, I));
unsigned N = atoi(Codes.back().c_str());
// Check that this is a valid matching constraint!
if (N >= ConstraintsSoFar.size() || ConstraintsSoFar[N].Type != isOutput||
Type != isInput)
return true; // Invalid constraint number.
// Note that operand #n has a matching input.
ConstraintsSoFar[N].hasMatchingInput = true;
} else {
// Single letter constraint.
Codes.push_back(std::string(I, I+1));
++I;
}
}
return false;
}
std::vector<InlineAsm::ConstraintInfo>
InlineAsm::ParseConstraints(const std::string &Constraints) {
std::vector<ConstraintInfo> Result;
// Scan the constraints string.
for (std::string::const_iterator I = Constraints.begin(),
E = Constraints.end(); I != E; ) {
ConstraintInfo Info;
// Find the end of this constraint.
std::string::const_iterator ConstraintEnd = std::find(I, E, ',');
if (ConstraintEnd == I || // Empty constraint like ",,"
Info.Parse(std::string(I, ConstraintEnd), Result)) {
Result.clear(); // Erroneous constraint?
break;
}
Result.push_back(Info);
// ConstraintEnd may be either the next comma or the end of the string. In
// the former case, we skip the comma.
I = ConstraintEnd;
if (I != E) {
++I;
if (I == E) { Result.clear(); break; } // don't allow "xyz,"
}
}
return Result;
}
/// Verify - Verify that the specified constraint string is reasonable for the
/// specified function type, and otherwise validate the constraint string.
bool InlineAsm::Verify(const FunctionType *Ty, const std::string &ConstStr) {
if (Ty->isVarArg()) return false;
std::vector<ConstraintInfo> Constraints = ParseConstraints(ConstStr);
// Error parsing constraints.
if (Constraints.empty() && !ConstStr.empty()) return false;
unsigned NumOutputs = 0, NumInputs = 0, NumClobbers = 0;
for (unsigned i = 0, e = Constraints.size(); i != e; ++i) {
switch (Constraints[i].Type) {
case InlineAsm::isOutput:
if (!Constraints[i].isIndirectOutput) {
if (NumInputs || NumClobbers) return false; // outputs come first.
++NumOutputs;
break;
}
// FALLTHROUGH for IndirectOutputs.
case InlineAsm::isInput:
if (NumClobbers) return false; // inputs before clobbers.
++NumInputs;
break;
case InlineAsm::isClobber:
++NumClobbers;
break;
}
}
if (NumOutputs > 1) return false; // Only one result allowed so far.
if ((Ty->getReturnType() != Type::VoidTy) != NumOutputs)
return false; // NumOutputs = 1 iff has a result type.
if (Ty->getNumParams() != NumInputs) return false;
return true;
}
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