Use uniform mechanism for OOM errors handling

This is a recommit of r333506, which was reverted in r333518.
The original commit message is below.

In r325551 many calls of malloc/calloc/realloc were replaces with calls of
their safe counterparts defined in the namespace llvm. There functions
generate crash if memory cannot be allocated, such behavior facilitates
handling of out of memory errors on Windows.

If the result of *alloc function were checked for success, the function was
not replaced with the safe variant. In these cases the calling function made
the error handling, like:

    T *NewElts = static_cast<T*>(malloc(NewCapacity*sizeof(T)));
    if (NewElts == nullptr)
      report_bad_alloc_error("Allocation of SmallVector element failed.");

Actually knowledge about the function where OOM occurred is useless. Moreover
having a single entry point for OOM handling is convenient for investigation
of memory problems. This change removes custom OOM errors handling and
replaces them with calls to functions `llvm::safe_*alloc`.

Declarations of `safe_*alloc` are moved to a separate include file, to avoid
cyclic dependency in SmallVector.h

Differential Revision: https://reviews.llvm.org/D47440

llvm-svn: 334344

1 files changed, 2 insertions, 4 deletions

diff --git a/llvm/lib/IR/DataLayout.cpp b/llvm/lib/IR/DataLayout.cpp
index fff2f67fe5a..62c67127276 100644
--- a/llvm/lib/IR/DataLayout.cpp
+++ b/llvm/lib/IR/DataLayout.cpp
@@ -596,10 +596,8 @@ const StructLayout *DataLayout::getStructLayout(StructType *Ty) const {
   // Otherwise, create the struct layout.  Because it is variable length, we
   // malloc it, then use placement new.
   int NumElts = Ty->getNumElements();
-  StructLayout *L =
-    (StructLayout *)malloc(sizeof(StructLayout)+(NumElts-1) * sizeof(uint64_t));
-  if (L == nullptr)
-    report_bad_alloc_error("Allocation of StructLayout elements failed.");
+  StructLayout *L = (StructLayout *)
+      safe_malloc(sizeof(StructLayout)+(NumElts-1) * sizeof(uint64_t));
 
   // Set SL before calling StructLayout's ctor.  The ctor could cause other
   // entries to be added to TheMap, invalidating our reference.