Add support for declaring register contraints in variables. They are only used
in asm statements:
register int foo asm("rdi");
asm("..." : ... "r" (foo) ...
We also only accept these variables if the constraint in the asm statement is "r".
This fixes most of PR3933.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@122643 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGStmt.cpp b/lib/CodeGen/CGStmt.cpp
index 098fe7f..1fcafe8 100644
--- a/lib/CodeGen/CGStmt.cpp
+++ b/lib/CodeGen/CGStmt.cpp
@@ -919,6 +919,32 @@
return Result;
}
+static std::string
+AddVariableConstraits(const std::string &Constraint, const Expr &AsmExpr,
+ const TargetInfo &Target, CodeGenModule &CGM,
+ const AsmStmt &Stmt) {
+ const DeclRefExpr *AsmDeclRef = dyn_cast<DeclRefExpr>(&AsmExpr);
+ if (!AsmDeclRef)
+ return Constraint;
+ const ValueDecl &Value = *AsmDeclRef->getDecl();
+ const VarDecl *Variable = dyn_cast<VarDecl>(&Value);
+ if (!Variable)
+ return Constraint;
+ AsmLabelAttr *Attr = Variable->getAttr<AsmLabelAttr>();
+ if (!Attr)
+ return Constraint;
+ llvm::StringRef Register = Attr->getLabel();
+ if (!Target.isValidGCCRegisterName(Register)) {
+ CGM.ErrorUnsupported(Variable, "__asm__");
+ return Constraint;
+ }
+ if (Constraint != "r") {
+ CGM.ErrorUnsupported(&Stmt, "__asm__");
+ return Constraint;
+ }
+ return "{" + Register.str() + "}";
+}
+
llvm::Value*
CodeGenFunction::EmitAsmInputLValue(const AsmStmt &S,
const TargetInfo::ConstraintInfo &Info,
@@ -1056,6 +1082,9 @@
const Expr *OutExpr = S.getOutputExpr(i);
OutExpr = OutExpr->IgnoreParenNoopCasts(getContext());
+ OutputConstraint = AddVariableConstraits(OutputConstraint, *OutExpr, Target,
+ CGM, S);
+
LValue Dest = EmitLValue(OutExpr);
if (!Constraints.empty())
Constraints += ',';
@@ -1133,6 +1162,11 @@
InputConstraint = SimplifyConstraint(InputConstraint.c_str(), Target,
&OutputConstraintInfos);
+ InputConstraint =
+ AddVariableConstraits(InputConstraint,
+ *InputExpr->IgnoreParenNoopCasts(getContext()),
+ Target, CGM, S);
+
llvm::Value *Arg = EmitAsmInput(S, Info, InputExpr, Constraints);
// If this input argument is tied to a larger output result, extend the