From 2a22004f6857c57dc483ea6180f0e1f86854bd13 Mon Sep 17 00:00:00 2001
From: Torok Edwin <edwintorok@gmail.com>
Date: Tue, 30 Mar 2010 10:08:26 +0000
Subject: [PATCH] Introduce another Reset() method in BumpPtrAllocator that
 calls a destructor on all objects it has allocated, if they are all of the
 same size and alignment. Use this to destruct all VNInfos allocated in
 LiveIntervalAnalysis (PR6653).

valnos is not reliable for this purpose, as seen in r99400
(which still leaked, and sometimes caused double frees).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@99881 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/Support/Allocator.h     |  6 ++++++
 lib/CodeGen/LiveIntervalAnalysis.cpp |  7 ++++++-
 lib/Support/Allocator.cpp            | 15 +++++++++++++++
 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/include/llvm/Support/Allocator.h b/include/llvm/Support/Allocator.h
index b1f59dc05e7..a58b9db27fa 100644
--- a/include/llvm/Support/Allocator.h
+++ b/include/llvm/Support/Allocator.h
@@ -134,6 +134,7 @@ class BumpPtrAllocator {
   static MallocSlabAllocator DefaultSlabAllocator;
 
 public:
+  typedef void (*DTorFunction)(void*);
   BumpPtrAllocator(size_t size = 4096, size_t threshold = 4096,
                    SlabAllocator &allocator = DefaultSlabAllocator);
   ~BumpPtrAllocator();
@@ -142,6 +143,11 @@ public:
   /// to the beginning of it, freeing all memory allocated so far.
   void Reset();
 
+  /// Reset - like Reset(), but call DTorFunction for each allocated
+  /// object. This assumes that all objects allocated with this allocator
+  /// had the same size and alignment specified here.
+  void Reset(size_t Size, size_t Alignment, DTorFunction DTor);
+
   /// Allocate - Allocate space at the specified alignment.
   ///
   void *Allocate(size_t Size, size_t Alignment);
diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index e657c46c721..53366b9f074 100644
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -82,6 +82,11 @@ void LiveIntervals::getAnalysisUsage(AnalysisUsage &AU) const {
   MachineFunctionPass::getAnalysisUsage(AU);
 }
 
+static void VNInfoDTor(void* Ptr)
+{
+   reinterpret_cast<VNInfo*>(Ptr)->~VNInfo();
+}
+
 void LiveIntervals::releaseMemory() {
   // Free the live intervals themselves.
   for (DenseMap<unsigned, LiveInterval*>::iterator I = r2iMap_.begin(),
@@ -91,7 +96,7 @@ void LiveIntervals::releaseMemory() {
   r2iMap_.clear();
 
   // Release VNInfo memroy regions after all VNInfo objects are dtor'd.
-  VNInfoAllocator.Reset();
+  VNInfoAllocator.Reset((unsigned)sizeof(VNInfo), alignof<VNInfo>(), VNInfoDTor);
   while (!CloneMIs.empty()) {
     MachineInstr *MI = CloneMIs.back();
     CloneMIs.pop_back();
diff --git a/lib/Support/Allocator.cpp b/lib/Support/Allocator.cpp
index 31b45c8d4aa..7433247c237 100644
--- a/lib/Support/Allocator.cpp
+++ b/lib/Support/Allocator.cpp
@@ -78,6 +78,21 @@ void BumpPtrAllocator::Reset() {
   End = ((char*)CurSlab) + CurSlab->Size;
 }
 
+void BumpPtrAllocator::Reset(size_t Size, size_t Alignment, DTorFunction DTor) {
+  if (Alignment == 0) Alignment = 1;
+  MemSlab *Slab = CurSlab;
+  while (Slab) {
+    char *End = Slab == CurSlab ? CurPtr : (char*)Slab + Slab->Size;
+    for (char *Ptr = (char*)Slab+1; Ptr < End; Ptr += Size) {
+	Ptr = AlignPtr(Ptr, Alignment);
+	if (Ptr + Size <= End)
+	    DTor(Ptr);
+    }
+    Slab = Slab->NextPtr;
+  }
+  Reset();
+}
+
 /// Allocate - Allocate space at the specified alignment.
 ///
 void *BumpPtrAllocator::Allocate(size_t Size, size_t Alignment) {
-- 
2.34.1