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, 13 insertions, 2 deletions

diff --git a/llvm/lib/Support/StringMap.cpp b/llvm/lib/Support/StringMap.cpp
index d2315966e32..4341da2d97b 100644
--- a/llvm/lib/Support/StringMap.cpp
+++ b/llvm/lib/Support/StringMap.cpp
@@ -52,14 +52,21 @@ StringMapImpl::StringMapImpl(unsigned InitSize, unsigned itemSize) {
 void StringMapImpl::init(unsigned InitSize) {
   assert((InitSize & (InitSize-1)) == 0 &&
          "Init Size must be a power of 2 or zero!");
-  NumBuckets = InitSize ? InitSize : 16;
+
+  unsigned NewNumBuckets = InitSize ? InitSize : 16;
   NumItems = 0;
   NumTombstones = 0;
   
-  TheTable = (StringMapEntryBase **)calloc(NumBuckets+1,
+  TheTable = (StringMapEntryBase **)calloc(NewNumBuckets+1,
                                            sizeof(StringMapEntryBase **) +
                                            sizeof(unsigned));
 
+  if (TheTable == nullptr)
+    report_bad_alloc_error("Allocation of StringMap table failed.");
+
+  // Set the member only if TheTable was successfully allocated
+  NumBuckets = NewNumBuckets;
+
   // Allocate one extra bucket, set it to look filled so the iterators stop at
   // end.
   TheTable[NumBuckets] = (StringMapEntryBase*)2;
@@ -215,6 +222,10 @@ unsigned StringMapImpl::RehashTable(unsigned BucketNo) {
   StringMapEntryBase **NewTableArray =
     (StringMapEntryBase **)calloc(NewSize+1, sizeof(StringMapEntryBase *) +
                                              sizeof(unsigned));
+
+  if (NewTableArray == nullptr)
+    report_bad_alloc_error("Allocation of StringMap hash table failed.");
+
   unsigned *NewHashArray = (unsigned *)(NewTableArray + NewSize + 1);
   NewTableArray[NewSize] = (StringMapEntryBase*)2;