[clang] [llvm] [RISCV][VLS] Support RISCV VLS calling convention (PR #100346)

[Craig Topper via cfe-commits]

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@@ -4768,6 +4768,15 @@ static void handleCallConvAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
   case ParsedAttr::AT_RISCVVectorCC:
     D->addAttr(::new (S.Context) RISCVVectorCCAttr(S.Context, AL));
     return;
+  case ParsedAttr::AT_RISCVVLSCC: {
+    // If the riscv_abi_vlen doesn't have any argument, default ABI_VLEN is 128.
+    unsigned VectorLength = 128;
+    if (AL.getNumArgs() &&
+        !S.checkUInt32Argument(AL, AL.getArgAsExpr(0), VectorLength))
+      return;
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topperc wrote:

Do we validate that the VectorLength is a legal value anywhere?

https://github.com/llvm/llvm-project/pull/100346