[IR][PGO] Verify the structure of VP metadata.

Author: mtrofin

llvm/include/llvm/IR/ProfDataUtils.h

@@ -28,6 +28,9 @@ LLVM_ABI bool hasProfMD(const Instruction &I);
 /// Checks if an MDNode contains Branch Weight Metadata
 LLVM_ABI bool isBranchWeightMD(const MDNode *ProfileData);
 
+/// Checks if an MDNode contains value profiling Metadata
+LLVM_ABI bool isValueProfileMD(const MDNode *ProfileData);
+
 /// Checks if an instructions has Branch Weight Metadata
 ///
 /// \param I The instruction to check

llvm/lib/IR/ProfDataUtils.cpp

@@ -96,7 +96,7 @@ bool isBranchWeightMD(const MDNode *ProfileData) {
   return isTargetMD(ProfileData, "branch_weights", MinBWOps);
 }
 
-static bool isValueProfileMD(const MDNode *ProfileData) {
+bool isValueProfileMD(const MDNode *ProfileData) {
   return isTargetMD(ProfileData, "VP", MinVPOps);
 }
 

llvm/lib/IR/Verifier.cpp

@@ -5026,9 +5026,14 @@ void Verifier::visitProfMetadata(Instruction &I, MDNode *MD) {
       Check(mdconst::dyn_extract<ConstantInt>(MDO),
             "!prof brunch_weights operand is not a const int");
     }
-  } else {
-    Check(ProfName == "VP", "expected either branch_weights or VP profile name",
+  } else if (ProfName == "VP") {
+    Check(isValueProfileMD(MD),"invalid value profiling metadata",MD);
+    Check(isa<CallBase>(I),
+          "value profiling !prof metadata is expected to be placed on call "
+          "instructions (which may be memops)",
           MD);
+  } else {
+    CheckFailed("expected either branch_weights or VP profile name", MD);
   }
 }