Support, IR, ADT: Check nullptr after allocation with malloc/realloc or calloc

As a follow up of the bad alloc handler patch, this patch introduces nullptr checks on pointers returned from the
malloc/realloc/calloc functions.  In addition some memory size assignments  are moved behind the allocation
of the corresponding memory to fulfill exception safe memory management (RAII).

patch by Klaus Kretzschmar

Differential Revision: https://reviews.llvm.org/D35414

llvm-svn: 308576

1 files changed, 7 insertions, 2 deletions

diff --git a/llvm/lib/Support/FoldingSet.cpp b/llvm/lib/Support/FoldingSet.cpp
index 4496d06a15f..94237954903 100644
--- a/llvm/lib/Support/FoldingSet.cpp
+++ b/llvm/lib/Support/FoldingSet.cpp
@@ -215,6 +215,10 @@ static void **GetBucketFor(unsigned Hash, void **Buckets, unsigned NumBuckets) {
 /// AllocateBuckets - Allocated initialized bucket memory.
 static void **AllocateBuckets(unsigned NumBuckets) {
   void **Buckets = static_cast<void**>(calloc(NumBuckets+1, sizeof(void*)));
+
+  if (Buckets == nullptr)
+    report_bad_alloc_error("Allocation of Buckets failed.");
+  
   // Set the very last bucket to be a non-null "pointer".
   Buckets[NumBuckets] = reinterpret_cast<void*>(-1);
   return Buckets;
@@ -271,10 +275,11 @@ void FoldingSetBase::GrowBucketCount(unsigned NewBucketCount) {
   assert(isPowerOf2_32(NewBucketCount) && "Bad bucket count!");
   void **OldBuckets = Buckets;
   unsigned OldNumBuckets = NumBuckets;
-  NumBuckets = NewBucketCount;
   
   // Clear out new buckets.
-  Buckets = AllocateBuckets(NumBuckets);
+  Buckets = AllocateBuckets(NewBucketCount);
+  // Set NumBuckets only if allocation of new buckets was succesful
+  NumBuckets = NewBucketCount; 
   NumNodes = 0;
 
   // Walk the old buckets, rehashing nodes into their new place.