// Checks if there is a conflict between the input and output lists with the
// clobbers list. If there's a conflict, returns the location of the
// conflicted clobber, else returns nullptr
static SourceLocation
getClobberConflictLocation(MultiExprArg Exprs, StringLiteral **Constraints,
StringLiteral **Clobbers, int NumClobbers,
const TargetInfo &Target, ASTContext &Cont) {
llvm::StringSet<> InOutVars;
// Collect all the input and output registers from the extended asm
// statement in order to check for conflicts with the clobber list
for (unsigned int i = 0; i < Exprs.size(); ++i) {
StringRef Constraint = Constraints[i]->getString();
StringRef InOutReg = Target.getConstraintRegister(
Constraint, extractRegisterName(Exprs[i], Target));
if (InOutReg != "")
InOutVars.insert(InOutReg);
}
// Check for each item in the clobber list if it conflicts with the input
// or output
for (int i = 0; i < NumClobbers; ++i) {
StringRef Clobber = Clobbers[i]->getString();
// We only check registers, therefore we don't check cc and memory
// clobbers
if (Clobber == "cc" || Clobber == "memory")
continue;
Clobber = Target.getNormalizedGCCRegisterName(Clobber, true);
// Go over the output's registers we collected
if (InOutVars.count(Clobber))
return Clobbers[i]->getLocStart();
}
return SourceLocation();
}
// Extracting the register name from the Expression value,
// if there is no register name to extract, returns ""
static StringRef extractRegisterName(const Expr *Expression,
const TargetInfo &Target) {
Expression = Expression->IgnoreImpCasts();
if (const DeclRefExpr *AsmDeclRef = dyn_cast<DeclRefExpr>(Expression)) {
// Handle cases where the expression is a variable
const VarDecl *Variable = dyn_cast<VarDecl>(AsmDeclRef->getDecl());
if (Variable && Variable->getStorageClass() == SC_Register) {
if (AsmLabelAttr *Attr = Variable->getAttr<AsmLabelAttr>())
if (Target.isValidGCCRegisterName(Attr->getLabel()))
return Target.getNormalizedGCCRegisterName(Attr->getLabel(), true);
}
}
return "";
}
