[llvm] [DirectX] Infrastructure to collect shader flags for each function (PR #112967)

[Chris B via llvm-commits]

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@@ -13,36 +13,79 @@
 
 #include "DXILShaderFlags.h"
 #include "DirectX.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/IR/DiagnosticInfo.h"
+#include "llvm/IR/DiagnosticPrinter.h"
 #include "llvm/IR/Instruction.h"
 #include "llvm/IR/Module.h"
+#include "llvm/Support/Error.h"
 #include "llvm/Support/FormatVariadic.h"
+#include "llvm/Support/raw_ostream.h"
 
 using namespace llvm;
 using namespace llvm::dxil;
 
-static void updateFlags(ComputedShaderFlags &Flags, const Instruction &I) {
-  Type *Ty = I.getType();
-  if (Ty->isDoubleTy()) {
-    Flags.Doubles = true;
+namespace {
+/// A simple Wrapper DiagnosticInfo that generates Module-level diagnostic
+/// for Shader Flags Analysis pass
+class DiagnosticInfoShaderFlags : public DiagnosticInfo {
+private:
+  const Twine &Msg;
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llvm-beanz wrote:

I get really nervous when someone stores a Twine. This effectively means that you must create and destroy this object in a single expression, otherwise the Twine or its attached arguments can go out of scope and you have a memory error.

It seems to me like what you really need is an adapter that converts an `llvm::Error` to a `DiagnosticInfo`, so that you can just pass the Error object right through.

We should add a utility to llvm/Support/Error to facilitate that. 

https://github.com/llvm/llvm-project/pull/112967