[llvm] [IR2Vec] Add support for flow-aware embeddings (PR #152613)

[S. VenkataKeerthy via llvm-commits]

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@@ -196,15 +218,46 @@ void SymbolicEmbedder::computeEmbeddings(const BasicBlock &BB) const {
   BBVecMap[&BB] = BBVector;
 }
 
-void SymbolicEmbedder::computeEmbeddings() const {
-  if (F.isDeclaration())
-    return;
+void FlowAwareEmbedder::computeEmbeddings(const BasicBlock &BB) const {
+  Embedding BBVector(Dimension, 0);
 
-  // Consider only the basic blocks that are reachable from entry
-  for (const BasicBlock *BB : depth_first(&F)) {
-    computeEmbeddings(*BB);
-    FuncVector += BBVecMap[BB];
+  // We consider only the non-debug and non-pseudo instructions
+  for (const auto &I : BB.instructionsWithoutDebug()) {
+    // TODO: Handle call instructions differently.
+    // For now, we treat them like other instructions
+    Embedding ArgEmb(Dimension, 0);
+    for (const auto &Op : I.operands()) {
+      // If the operand is defined elsewhere, we use its embedding
+      if (const Instruction *DefInst = dyn_cast<Instruction>(Op)) {
+        auto DefIt = InstVecMap.find(DefInst);
+        assert(DefIt != InstVecMap.end() &&
+               "Instruction should have been processed before its operands");
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svkeerthy wrote:

Yeah, cleaned up. Thanks!

https://github.com/llvm/llvm-project/pull/152613