[Bitcode] Verify types for aggregate initializers

Unfortunately all the nice error messages get lost because we
don't forward errors from lazy value materialization.

Fixes #117707.

Author: nikic

llvm/lib/Bitcode/Reader/BitcodeReader.cpp

@@ -1663,15 +1663,42 @@ Expected<Value *> BitcodeReader::materializeValue(unsigned StartValID,
           C = BlockAddress::get(Fn, BB);
           break;
         }
-        case BitcodeConstant::ConstantStructOpcode:
-          C = ConstantStruct::get(cast<StructType>(BC->getType()), ConstOps);
+        case BitcodeConstant::ConstantStructOpcode: {
+          auto *ST = cast<StructType>(BC->getType());
+          if (ST->getNumElements() != ConstOps.size())
+            return error("Invalid number of elements in struct initializer");
+
+          for (const auto [Ty, Op] : zip(ST->elements(), ConstOps))
+            if (Op->getType() != Ty)
+              return error("Incorrect type in struct initializer");
+
+          C = ConstantStruct::get(ST, ConstOps);
           break;
-        case BitcodeConstant::ConstantArrayOpcode:
-          C = ConstantArray::get(cast<ArrayType>(BC->getType()), ConstOps);
+        }
+        case BitcodeConstant::ConstantArrayOpcode: {
+          auto *AT = cast<ArrayType>(BC->getType());
+          if (AT->getNumElements() != ConstOps.size())
+            return error("Invalid number of elements in array initializer");
+
+          for (Constant *Op : ConstOps)
+            if (Op->getType() != AT->getElementType())
+              return error("Incorrect type in array initializer");
+
+          C = ConstantArray::get(AT, ConstOps);
           break;
-        case BitcodeConstant::ConstantVectorOpcode:
+        }
+        case BitcodeConstant::ConstantVectorOpcode: {
+          auto *VT = cast<FixedVectorType>(BC->getType());
+          if (VT->getNumElements() != ConstOps.size())
+            return error("Invalid number of elements in vector initializer");
+
+          for (Constant *Op : ConstOps)
+            if (Op->getType() != VT->getElementType())
+              return error("Incorrect type in vector initializer");
+
           C = ConstantVector::get(ConstOps);
           break;
+        }
         case Instruction::GetElementPtr:
           C = ConstantExpr::getGetElementPtr(
               BC->SrcElemTy, ConstOps[0], ArrayRef(ConstOps).drop_front(),

llvm/test/Bitcode/Inputs/invalid-initializer.bc

@@ -285,3 +285,8 @@ RUN: not llvm-dis -disable-output %p/Inputs/invalid-forward-declare.bc 2>&1 | \
 RUN:   FileCheck --check-prefix=INVALID-FORWARD-DECLARE %s
 
 INVALID-FORWARD-DECLARE: Assigned value does not match type of forward declaration
+
+RUN: not llvm-dis -disable-output %p/Inputs/invalid-initializer.bc 2>&1 | \
+RUN:   FileCheck --check-prefix=INVALID-INITIALIZER %s
+
+INVALID-INITIALIZER: Invalid record