[TBAA] Drop support for "old style" scalar TBAA tags

Summary:
We've had support for auto upgrading old style scalar TBAA access
metadata tags into the "new" struct path aware TBAA metadata for 3 years
now.  The only way to actually generate old style TBAA was explicitly
through the IRBuilder API.  I think this is a good time for dropping
support for old style scalar TBAA.

I'm not removing support for textual or bitcode upgrade -- if you have
IR with the old style scalar TBAA tags that go through the AsmParser orf
the bitcode parser before LLVM sees them, they will keep working as
usual.

Note:

  %val = load i32, i32* %ptr, !tbaa !N
  !N = < scalar tbaa node >

is equivalent to

  %val = load i32, i32* %ptr, !tbaa !M
  !N = < scalar tbaa node >
  !M = !{!N, !N, 0}

Reviewers: manmanren, chandlerc, sunfish

Subscribers: mcrosier, llvm-commits, mgorny

Differential Revision: https://reviews.llvm.org/D26229

llvm-svn: 286291

1 files changed, 63 insertions, 0 deletions

diff --git a/llvm/unittests/Analysis/TBAATest.cpp b/llvm/unittests/Analysis/TBAATest.cpp
new file mode 100644
index 00000000000..98899dd553d
--- /dev/null
+++ b/llvm/unittests/Analysis/TBAATest.cpp
@@ -0,0 +1,63 @@
+//===--- TBAATest.cpp - Mixed TBAA unit tests -----------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/AliasAnalysisEvaluator.h"
+#include "llvm/Analysis/Passes.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/MDBuilder.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/LegacyPassManager.h"
+#include "llvm/IR/Verifier.h"
+#include "llvm/Support/CommandLine.h"
+#include "gtest/gtest.h"
+
+namespace llvm {
+namespace {
+
+class OldTBAATest : public testing::Test {
+protected:
+  OldTBAATest() : M("MixedTBAATest", C), MD(C) {}
+
+  LLVMContext C;
+  Module M;
+  MDBuilder MD;
+};
+
+TEST_F(OldTBAATest, checkVerifierBehavior) {
+  // C++ unit test case to avoid going through the auto upgrade logic.
+
+  FunctionType *FTy = FunctionType::get(Type::getVoidTy(C), {});
+  auto *F = cast<Function>(M.getOrInsertFunction("f", FTy));
+  auto *BB = BasicBlock::Create(C, "entry", F);
+  auto *IntType = Type::getInt32Ty(C);
+  auto *PtrType = Type::getInt32PtrTy(C);
+  auto *SI = new StoreInst(ConstantInt::get(IntType, 42),
+                           ConstantPointerNull::get(PtrType), BB);
+  ReturnInst::Create(C, nullptr, BB);
+
+  auto *RootMD = MD.createTBAARoot("Simple C/C++ TBAA");
+  auto *MD1 = MD.createTBAANode("omnipotent char", RootMD);
+  auto *MD2 = MD.createTBAANode("int", MD1);
+  SI->setMetadata(LLVMContext::MD_tbaa, MD2);
+
+  SmallVector<char, 0> ErrorMsg;
+  raw_svector_ostream Outs(ErrorMsg);
+
+  StringRef ExpectedFailureMsg(
+      "Old-style TBAA is no longer allowed, use struct-path TBAA instead");
+
+  EXPECT_TRUE(verifyFunction(*F, &Outs));
+  EXPECT_TRUE(StringRef(ErrorMsg.begin(), ErrorMsg.size())
+                  .startswith(ExpectedFailureMsg));
+}
+
+} // end anonymous namspace
+} // end llvm namespace