[PATCH] D84293: Add an assertion in SmallVector::push_back()

[Mehdi AMINI via Phabricator via llvm-commits]

mehdi_amini created this revision.
mehdi_amini added a reviewer: bkramer.
Herald added subscribers: llvm-commits, dexonsmith.
Herald added a project: LLVM.

This assertion ensures the input value isn't part of the vector when
growing is required. In such cases the vector will grow and the input
value is invalidated before being read from.

This found 14 failed Tests.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D84293

Files:
  llvm/include/llvm/ADT/SmallVector.h
  llvm/include/llvm/MC/MCInst.h


Index: llvm/include/llvm/MC/MCInst.h
===================================================================
--- llvm/include/llvm/MC/MCInst.h
+++ llvm/include/llvm/MC/MCInst.h
@@ -181,7 +181,10 @@
   MCOperand &getOperand(unsigned i) { return Operands[i]; }
   unsigned getNumOperands() const { return Operands.size(); }
 
-  void addOperand(const MCOperand &Op) { Operands.push_back(Op); }
+  void addOperand(const MCOperand &Op) {
+    Operands.reserve(Operands.size() + 1);
+    Operands.push_back(Op);
+  }
 
   using iterator = SmallVectorImpl<MCOperand>::iterator;
   using const_iterator = SmallVectorImpl<MCOperand>::const_iterator;
Index: llvm/include/llvm/ADT/SmallVector.h
===================================================================
--- llvm/include/llvm/ADT/SmallVector.h
+++ llvm/include/llvm/ADT/SmallVector.h
@@ -129,6 +129,13 @@
     this->Size = this->Capacity = 0; // FIXME: Setting Capacity to 0 is suspect.
   }
 
+  void assertSafeToPush(const void *Elt) {
+    assert(
+        (Elt < begin() || Elt >= end() || this->size() < this->capacity()) &&
+        "Attempting to push_back to the vector an element of the vector without"
+        " enough space reserved");
+  }
+
 public:
   using size_type = size_t;
   using difference_type = ptrdiff_t;
@@ -244,6 +251,7 @@
 
 public:
   void push_back(const T &Elt) {
+    this->assertSafeToPush(&Elt);
     if (LLVM_UNLIKELY(this->size() >= this->capacity()))
       this->grow();
     ::new ((void*) this->end()) T(Elt);
@@ -251,6 +259,7 @@
   }
 
   void push_back(T &&Elt) {
+    this->assertSafeToPush(&Elt);
     if (LLVM_UNLIKELY(this->size() >= this->capacity()))
       this->grow();
     ::new ((void*) this->end()) T(::std::move(Elt));
@@ -346,6 +355,7 @@
 
 public:
   void push_back(const T &Elt) {
+    this->assertSafeToPush(&Elt);
     if (LLVM_UNLIKELY(this->size() >= this->capacity()))
       this->grow();
     memcpy(reinterpret_cast<void *>(this->end()), &Elt, sizeof(T));


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