================
@@ -7061,6 +7061,67 @@ class ArraySectionExpr : public Expr {
void setRBracketLoc(SourceLocation L) { RBracketLoc = L; }
};
+/// This class represents temporary values used to represent inout and out
+/// arguments in HLSL. From the callee perspective these parameters are more or
+/// less __restrict__ T&. They are guaranteed to not alias any memory. inout
+/// parameters are initialized by the caller, and out parameters are references
+/// to uninitialized memory.
+///
+/// In the caller, the argument expression creates a temporary in local memory
+/// and the address of the temporary is passed into the callee. There may be
+/// implicit conversion sequences to initialize the temporary, and on
expiration
+/// of the temporary an inverse conversion sequence is applied as a write-back
+/// conversion to the source l-value.
+class HLSLOutArgExpr : public Expr {
+ friend class ASTStmtReader;
+
+ Expr *Base;
+ Expr *Writeback;
+ OpaqueValueExpr *OpaqueVal;
+ bool IsInOut;
+
+ HLSLOutArgExpr(QualType Ty, Expr *B, Expr *WB, OpaqueValueExpr *OpV,
+ bool IsInOut)
+ : Expr(HLSLOutArgExprClass, Ty, VK_LValue, OK_Ordinary), Base(B),
+ Writeback(WB), OpaqueVal(OpV), IsInOut(IsInOut) {
+ assert(!Ty->isDependentType() && "HLSLOutArgExpr given a dependent type!");
+ }
+
+ explicit HLSLOutArgExpr(EmptyShell Shell)
+ : Expr(HLSLOutArgExprClass, Shell) {}
+
+public:
+ static HLSLOutArgExpr *Create(const ASTContext &C, QualType Ty, Expr *Base,
+ bool IsInOut, Expr *WB, OpaqueValueExpr *OpV);
+ static HLSLOutArgExpr *CreateEmpty(const ASTContext &Ctx);
+
+ const Expr *getBase() const { return Base; }
----------------
rjmccall wrote:
You need to document what the expressions are here, because it's pretty subtle.
So the way you've written it, this a conversion of the base l-value to the
type of the parameter, the writeback is an assignment of the temporary result
back to the base l-value, and the OVE represents the temporary result. I think
this is problematic, though; see the comment in Sema.
https://github.com/llvm/llvm-project/pull/101083
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