[llvm-branch-commits] [clang] [llvm] [HLSL][DirectX] Add support for `rootsig` as a target environment (PR #156373)

[Justin Bogner via llvm-branch-commits]

================
@@ -140,8 +143,19 @@ analyzeModule(Module &M) {
     RSD.StaticSamplersOffset = 0u;
 
     RSDMap.insert(std::make_pair(F, RSD));
+  };
+
+  if (M.getTargetTriple().getEnvironment() ==
+      Triple::EnvironmentType::RootSignature) {
+    assert(RootSignatureNode->getNumOperands() == 1);
+    MDNode *RSDefNode = RootSignatureNode->getOperand(0);
+    HandleNode(RSDefNode, true);
+    return RSDMap;
   }
 
+  for (MDNode *RSDefNode : RootSignatureNode->operands())
+    HandleNode(RSDefNode);
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bogner wrote:

It's mostly a matter of style, but I think it might be slightly more readable to keep this as a loop rather than pulling the lambda out like this. You'd need to do the root signature book keeping before the loop:
```c++
  bool AllowNullFunctions = false;
  if (M.getTargetTriple().getEnvironment() ==
      Triple::EnvironmentType::RootSignature) {
    assert(RootSignatureNode->getNumOperands() == 1);
    AllowNullFunctions = true;
  }

  for (MDNode *RSDefNode : RootSignatureNode->operands())
    // ...
```

What do you think?

https://github.com/llvm/llvm-project/pull/156373