[clang] [llvm] [CaptureTracking][FunctionAttrs] Add support for CaptureInfo (PR #125880)

[via cfe-commits]

================
@@ -1303,27 +1341,42 @@ static void addArgumentAttrs(const SCCNodeSet &SCCNodes,
       ArgumentSCCNodes.insert(I->Definition);
     }
 
-    bool SCCCaptured = false;
+    // At the SCC level, only track merged CaptureComponents. We're not
+    // currently prepared to handle propagation of return-only captures across
+    // the SCC.
+    CaptureComponents CC = CaptureComponents::None;
     for (ArgumentGraphNode *N : ArgumentSCC) {
       for (ArgumentGraphNode *Use : N->Uses) {
         Argument *A = Use->Definition;
-        if (A->hasNoCaptureAttr() || ArgumentSCCNodes.count(A))
-          continue;
-        SCCCaptured = true;
+        if (ArgumentSCCNodes.count(A))
+          CC |= Use->CC;
+        else
+          CC |= CaptureComponents(A->getAttributes().getCaptureInfo());
         break;
       }
-      if (SCCCaptured)
+      if (capturesAll(CC))
         break;
     }
-    if (SCCCaptured)
-      continue;
 
-    for (ArgumentGraphNode *N : ArgumentSCC) {
-      Argument *A = N->Definition;
-      A->addAttr(
-          Attribute::getWithCaptureInfo(A->getContext(), CaptureInfo::none()));
-      ++NumNoCapture;
-      Changed.insert(A->getParent());
+    if (!capturesAll(CC)) {
+      for (ArgumentGraphNode *N : ArgumentSCC) {
+        Argument *A = N->Definition;
+        CaptureInfo CI = N->CC | CC;
+        A->addAttr(Attribute::getWithCaptureInfo(A->getContext(), CI));
+        addCapturesStat(CI);
+        Changed.insert(A->getParent());
+      }
+    }
+
+    // TODO(captures): Ignore address-only captures.
+    if (!capturesNothing(CC)) {
+      // As the pointer may be captured, determine the pointer attributes
+      // looking at each argument invidivually.
+      for (ArgumentGraphNode *N : ArgumentSCC) {
+        if (DetermineAccessAttrsForSingleton(N->Definition))
+          Changed.insert(N->Definition->getParent());
+      }
----------------
goldsteinn wrote:

What is this for?

https://github.com/llvm/llvm-project/pull/125880