Reapply "[TBAA] Add verifier for tbaa.struct metadata (#86709)"

This reverts commit b9cd48f96acdd07c627ccafbf4386a1f3dcd6c51.

-------------------------------------------------------------
Original commit message:

Adds logic to the IR verifier that checks whether !tbaa.struct nodes are
well-formed. That is, it checks that the operands of !tbaa.struct nodes
are in groups of three, that each group of three operands consists of
two integers and a valid tbaa node, and that the regions described by
the offset and size operands are non-overlapping.

PR: https://github.com/llvm/llvm-project/pull/86709

1 files changed, 32 insertions, 0 deletions

diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index 25cb99f..516d4a0 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -5122,6 +5122,9 @@ void Verifier::visitInstruction(Instruction &I) {
   if (MDNode *TBAA = I.getMetadata(LLVMContext::MD_tbaa))
     TBAAVerifyHelper.visitTBAAMetadata(I, TBAA);
 
+  if (MDNode *TBAA = I.getMetadata(LLVMContext::MD_tbaa_struct))
+    TBAAVerifyHelper.visitTBAAStructMetadata(I, TBAA);
+
   if (MDNode *MD = I.getMetadata(LLVMContext::MD_noalias))
     visitAliasScopeListMetadata(MD);
   if (MDNode *MD = I.getMetadata(LLVMContext::MD_alias_scope))
@@ -7453,6 +7456,35 @@ bool TBAAVerifier::visitTBAAMetadata(Instruction &I, const MDNode *MD) {
   return true;
 }
 
+bool TBAAVerifier::visitTBAAStructMetadata(Instruction &I, const MDNode *MD) {
+  CheckTBAA(MD->getNumOperands() % 3 == 0,
+            "tbaa.struct operands must occur in groups of three", &I, MD);
+
+  // Each group of three operands must consist of two integers and a
+  // tbaa node. Moreover, the regions described by the offset and size
+  // operands must be non-overlapping.
+  std::optional<APInt> NextFree;
+  for (unsigned int Idx = 0; Idx < MD->getNumOperands(); Idx += 3) {
+    auto *OffsetCI =
+        mdconst::dyn_extract_or_null<ConstantInt>(MD->getOperand(Idx));
+    CheckTBAA(OffsetCI, "Offset must be a constant integer", &I, MD);
+
+    auto *SizeCI =
+        mdconst::dyn_extract_or_null<ConstantInt>(MD->getOperand(Idx + 1));
+    CheckTBAA(SizeCI, "Size must be a constant integer", &I, MD);
+
+    MDNode *TBAA = dyn_cast_or_null<MDNode>(MD->getOperand(Idx + 2));
+    CheckTBAA(TBAA, "TBAA tag missing", &I, MD);
+    visitTBAAMetadata(I, TBAA);
+
+    bool NonOverlapping = !NextFree || NextFree->ule(OffsetCI->getValue());
+    CheckTBAA(NonOverlapping, "Overlapping tbaa.struct regions", &I, MD);
+
+    NextFree = OffsetCI->getValue() + SizeCI->getValue();
+  }
+  return true;
+}
+
 char VerifierLegacyPass::ID = 0;
 INITIALIZE_PASS(VerifierLegacyPass, "verify", "Module Verifier", false, false)