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

[Chris B via llvm-commits]

================
@@ -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;
+  const Module &Mod;
+
+public:
+  /// \p M is the module for which the diagnostic is being emitted. \p Msg is
+  /// the message to show. Note that this class does not copy this message, so
+  /// this reference must be valid for the whole life time of the diagnostic.
+  DiagnosticInfoShaderFlags(const Module &M, const Twine &Msg,
+                            DiagnosticSeverity Severity = DS_Error)
+      : DiagnosticInfo(DK_Unsupported, Severity), Msg(Msg), Mod(M) {}
+
+  void print(DiagnosticPrinter &DP) const override {
+    DP << Mod.getName() << ": " << Msg << '\n';
+  }
+};
+} // namespace
+
+void DXILModuleShaderFlagsInfo::updateFunctionFlags(ComputedShaderFlags &CSF,
+                                                    const Instruction &I) {
+  if (!CSF.Doubles) {
+    CSF.Doubles = I.getType()->isDoubleTy();
+  }
----------------
llvm-beanz wrote:

nit: https://llvm.org/docs/CodingStandards.html#don-t-use-braces-on-simple-single-statement-bodies-of-if-else-loop-statements
```suggestion
  if (!CSF.Doubles)
    CSF.Doubles = I.getType()->isDoubleTy();
```

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