[llvm] [IR] Introduce !captures metadata (PR #160913)

[Yingwei Zheng via llvm-commits]

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@@ -3025,6 +3025,9 @@ static void combineMetadata(Instruction *K, const Instruction *J,
         // Preserve !nosanitize if both K and J have it.
         K->setMetadata(Kind, JMD);
         break;
+      case LLVMContext::MD_captures:
+        K->setMetadata(Kind, JMD ? MDNode::concatenate(JMD, KMD) : nullptr);
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dtcxzyw wrote:

`address_is_null + address` can be `address`. It may be better to add a `StoreInst::setCaptureComponents` helper to update MD nodes. Then we can guarantee the list is always canonical.


https://github.com/llvm/llvm-project/pull/160913