[libc-commits] [clang] [libc] [llvm] [NVPTX] Implement variadic functions using IR lowering (PR #96015)

[Jon Chesterfield via libc-commits]

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@@ -938,6 +938,37 @@ struct Amdgpu final : public VariadicABIInfo {
   }
 };
 
+struct NVPTX final : public VariadicABIInfo {
+
+  bool enableForTarget() override { return true; }
+
+  bool vaListPassedInSSARegister() override { return true; }
+
+  Type *vaListType(LLVMContext &Ctx) override {
+    return PointerType::getUnqual(Ctx);
+  }
+
+  Type *vaListParameterType(Module &M) override {
+    return PointerType::getUnqual(M.getContext());
+  }
+
+  Value *initializeVaList(Module &M, LLVMContext &Ctx, IRBuilder<> &Builder,
+                          AllocaInst *, Value *Buffer) override {
+    return Builder.CreateAddrSpaceCast(Buffer, vaListParameterType(M));
+  }
+
+  VAArgSlotInfo slotInfo(const DataLayout &DL, Type *Parameter) override {
+    // NVPTX doesn't apply minimum alignment to types present in structs. Types
+    // with alignment less than four should be promoted by the compiler and will
+    // get the proper minimum alignment in those cases.
+    const unsigned MinAlign = 1;
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JonChesterfield wrote:

I don't think this does what the comment says it should. Also some half types might be passed with 2 byte alignment, others might be passed promoted to double.

https://github.com/llvm/llvm-project/pull/96015