[TableGen] Prevent DagInit from leaking its Args and ArgNames when they exceed the size of the SmallVector.

DagInits are allocated in a BumpPtrAllocator so they are never destructed. This means the destructor for the SmallVector never runs.

To fix this we now allocate the vectors in the BumpPtrAllocator too using TrailingObjects.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@304077 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 42 insertions, 31 deletions

diff --git a/include/llvm/TableGen/Record.h b/include/llvm/TableGen/Record.h
index ced21c2efb2..d14a56cb87e 100644
--- a/include/llvm/TableGen/Record.h
+++ b/include/llvm/TableGen/Record.h
@@ -1137,17 +1137,19 @@ public:
 /// to have at least one value then a (possibly empty) list of arguments.  Each
 /// argument can have a name associated with it.
 ///
-class DagInit : public TypedInit, public FoldingSetNode {
+class DagInit final : public TypedInit, public FoldingSetNode,
+                      public TrailingObjects<DagInit, Init *, StringInit *> {
   Init *Val;
   StringInit *ValName;
-  SmallVector<Init*, 4> Args;
-  SmallVector<StringInit*, 4> ArgNames;
+  unsigned NumArgs;
+  unsigned NumArgNames;
 
-  DagInit(Init *V, StringInit *VN, ArrayRef<Init *> ArgRange,
-          ArrayRef<StringInit *> NameRange)
+  DagInit(Init *V, StringInit *VN, unsigned NumArgs, unsigned NumArgNames)
       : TypedInit(IK_DagInit, DagRecTy::get()), Val(V), ValName(VN),
-          Args(ArgRange.begin(), ArgRange.end()),
-          ArgNames(NameRange.begin(), NameRange.end()) {}
+        NumArgs(NumArgs), NumArgNames(NumArgNames) {}
+
+  friend TrailingObjects;
+  size_t numTrailingObjects(OverloadToken<Init *>) const { return NumArgs; }
 
 public:
   DagInit(const DagInit &Other) = delete;
@@ -1173,20 +1175,24 @@ public:
     return ValName ? ValName->getValue() : StringRef();
   }
 
-  unsigned getNumArgs() const { return Args.size(); }
+  unsigned getNumArgs() const { return NumArgs; }
   Init *getArg(unsigned Num) const {
-    assert(Num < Args.size() && "Arg number out of range!");
-    return Args[Num];
+    assert(Num < NumArgs && "Arg number out of range!");
+    return getTrailingObjects<Init *>()[Num];
   }
   StringInit *getArgName(unsigned Num) const {
-    assert(Num < ArgNames.size() && "Arg number out of range!");
-    return ArgNames[Num];
+    assert(Num < NumArgNames && "Arg number out of range!");
+    return getTrailingObjects<StringInit *>()[Num];
   }
   StringRef getArgNameStr(unsigned Num) const {
     StringInit *Init = getArgName(Num);
     return Init ? Init->getValue() : StringRef();
   }
 
+  ArrayRef<StringInit *> getArgNames() const {
+    return makeArrayRef(getTrailingObjects<StringInit *>(), NumArgNames);
+  }
+
   Init *resolveReferences(Record &R, const RecordVal *RV) const override;
 
   std::string getAsString() const override;
@@ -1194,20 +1200,20 @@ public:
   typedef SmallVectorImpl<Init*>::const_iterator       const_arg_iterator;
   typedef SmallVectorImpl<StringInit*>::const_iterator const_name_iterator;
 
-  inline const_arg_iterator  arg_begin() const { return Args.begin(); }
-  inline const_arg_iterator  arg_end  () const { return Args.end();   }
+  inline const_arg_iterator  arg_begin() const { return getTrailingObjects<Init *>(); }
+  inline const_arg_iterator  arg_end  () const { return arg_begin() + NumArgs;   }
   inline iterator_range<const_arg_iterator> args() const {
     return llvm::make_range(arg_begin(), arg_end());
   }
 
-  inline size_t              arg_size () const { return Args.size();  }
-  inline bool                arg_empty() const { return Args.empty(); }
+  inline size_t              arg_size () const { return NumArgs;  }
+  inline bool                arg_empty() const { return NumArgs == 0; }
 
-  inline const_name_iterator name_begin() const { return ArgNames.begin(); }
-  inline const_name_iterator name_end  () const { return ArgNames.end();   }
+  inline const_name_iterator name_begin() const { return getTrailingObjects<StringInit *>(); }
+  inline const_name_iterator name_end  () const { return name_begin() + NumArgNames;   }
 
-  inline size_t              name_size () const { return ArgNames.size();  }
-  inline bool                name_empty() const { return ArgNames.empty(); }
+  inline size_t              name_size () const { return NumArgNames;  }
+  inline bool                name_empty() const { return NumArgNames == 0; }
 
   Init *getBit(unsigned Bit) const override {
     llvm_unreachable("Illegal bit reference off dag");
diff --git a/lib/TableGen/Record.cpp b/lib/TableGen/Record.cpp
index 3bd0db6c96b..09f9759ce7d 100644
--- a/lib/TableGen/Record.cpp
+++ b/lib/TableGen/Record.cpp
@@ -1501,7 +1501,12 @@ DagInit::get(Init *V, StringInit *VN, ArrayRef<Init *> ArgRange,
   if (DagInit *I = ThePool.FindNodeOrInsertPos(ID, IP))
     return I;
 
-  DagInit *I = new(Allocator) DagInit(V, VN, ArgRange, NameRange);
+  void *Mem = Allocator.Allocate(totalSizeToAlloc<Init *, StringInit *>(ArgRange.size(), NameRange.size()), alignof(BitsInit));
+  DagInit *I = new(Mem) DagInit(V, VN, ArgRange.size(), NameRange.size());
+  std::uninitialized_copy(ArgRange.begin(), ArgRange.end(),
+                          I->getTrailingObjects<Init *>());
+  std::uninitialized_copy(NameRange.begin(), NameRange.end(),
+                          I->getTrailingObjects<StringInit *>());
   ThePool.InsertNode(I, IP);
   return I;
 }
@@ -1521,7 +1526,7 @@ DagInit::get(Init *V, StringInit *VN,
 }
 
 void DagInit::Profile(FoldingSetNodeID &ID) const {
-  ProfileDagInit(ID, Val, ValName, Args, ArgNames);
+  ProfileDagInit(ID, Val, ValName, makeArrayRef(getTrailingObjects<Init *>(), NumArgs), makeArrayRef(getTrailingObjects<StringInit *>(), NumArgNames));
 }
 
 Init *DagInit::convertInitializerTo(RecTy *Ty) const {
@@ -1533,9 +1538,9 @@ Init *DagInit::convertInitializerTo(RecTy *Ty) const {
 
 Init *DagInit::resolveReferences(Record &R, const RecordVal *RV) const {
   SmallVector<Init*, 8> NewArgs;
-  NewArgs.reserve(Args.size());
+  NewArgs.reserve(arg_size());
   bool ArgsChanged = false;
-  for (const Init *Arg : Args) {
+  for (const Init *Arg : args()) {
     Init *NewArg = Arg->resolveReferences(R, RV);
     NewArgs.push_back(NewArg);
     ArgsChanged |= NewArg != Arg;
@@ -1543,7 +1548,7 @@ Init *DagInit::resolveReferences(Record &R, const RecordVal *RV) const {
 
   Init *Op = Val->resolveReferences(R, RV);
   if (Op != Val || ArgsChanged)
-    return DagInit::get(Op, ValName, NewArgs, ArgNames);
+    return DagInit::get(Op, ValName, NewArgs, getArgNames());
 
   return const_cast<DagInit *>(this);
 }
@@ -1552,12 +1557,12 @@ std::string DagInit::getAsString() const {
   std::string Result = "(" + Val->getAsString();
   if (ValName)
     Result += ":" + ValName->getAsUnquotedString();
-  if (!Args.empty()) {
-    Result += " " + Args[0]->getAsString();
-    if (ArgNames[0]) Result += ":$" + ArgNames[0]->getAsUnquotedString();
-    for (unsigned i = 1, e = Args.size(); i != e; ++i) {
-      Result += ", " + Args[i]->getAsString();
-      if (ArgNames[i]) Result += ":$" + ArgNames[i]->getAsUnquotedString();
+  if (!arg_empty()) {
+    Result += " " + getArg(0)->getAsString();
+    if (getArgName(0)) Result += ":$" + getArgName(0)->getAsUnquotedString();
+    for (unsigned i = 1, e = getNumArgs(); i != e; ++i) {
+      Result += ", " + getArg(i)->getAsString();
+      if (getArgName(i)) Result += ":$" + getArgName(i)->getAsUnquotedString();
     }
   }
   return Result + ")";