[PATCH] D136656: [IR Verifier] didn't check if switch case is constant, align IR Verifier's check with LLParser.

[Peter Rong via Phabricator via llvm-commits]

Peter created this revision.
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If a programmer incorrectly `Switch->setOperand()` and `Verifier` will pass, causing problems when dumping this `Module`
This patch aligns SwitchInst's check with LLParser. It also includes a test to justify the patch.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D136656

Files:
  llvm/lib/IR/Verifier.cpp
  llvm/unittests/IR/VerifierTest.cpp


Index: llvm/unittests/IR/VerifierTest.cpp
===================================================================
--- llvm/unittests/IR/VerifierTest.cpp
+++ llvm/unittests/IR/VerifierTest.cpp
@@ -270,5 +270,36 @@
   EXPECT_TRUE(verifyFunction(*F2));
 }
 
+TEST(VerifierTest, SwitchInst) {
+  LLVMContext C;
+  Module M("M", C);
+  IntegerType *Int32Ty = Type::getInt32Ty(C);
+  FunctionType *FTy =
+      FunctionType::get(Type::getVoidTy(C), {Int32Ty, Int32Ty},
+                        /*isVarArg=*/false);
+  Function *F = Function::Create(FTy, Function::ExternalLinkage, "foo", M);
+  BasicBlock *Entry = BasicBlock::Create(C, "entry", F);
+  BasicBlock *Default = BasicBlock::Create(C, "default", F);
+  BasicBlock *OnOne = BasicBlock::Create(C, "on_one", F);
+  BasicBlock *OnTwo = BasicBlock::Create(C, "on_two", F);
+
+  BasicBlock *Exit = BasicBlock::Create(C, "exit", F);
+
+  BranchInst::Create(Exit, Default);
+  BranchInst::Create(Exit, OnTwo);
+  BranchInst::Create(Exit, OnOne);
+  ReturnInst::Create(C, Exit);
+
+  Value *Cond = F->getArg(0);
+  SwitchInst *Switch = SwitchInst::Create(Cond, Default, 2, Entry);
+  Switch->addCase(ConstantInt::get(Int32Ty, 1), OnOne);
+  Switch->addCase(ConstantInt::get(Int32Ty, 2), OnTwo);
+
+  EXPECT_FALSE(verifyFunction(*F));
+  // set one case value to function argument.
+  Switch->setOperand(2, F->getArg(1));
+  EXPECT_TRUE(verifyFunction(*F));
+}
+
 } // end anonymous namespace
 } // end namespace llvm
Index: llvm/lib/IR/Verifier.cpp
===================================================================
--- llvm/lib/IR/Verifier.cpp
+++ llvm/lib/IR/Verifier.cpp
@@ -2879,6 +2879,8 @@
   Type *SwitchTy = SI.getCondition()->getType();
   SmallPtrSet<ConstantInt*, 32> Constants;
   for (auto &Case : SI.cases()) {
+    Check(isa<ConstantInt>(SI.getOperand(Case.getCaseIndex() * 2 + 2)),
+          "Case value is not a constant integer.", &SI);
     Check(Case.getCaseValue()->getType() == SwitchTy,
           "Switch constants must all be same type as switch value!", &SI);
     Check(Constants.insert(Case.getCaseValue()).second,


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