[ASan] Do allocate memory even for zero-size allocation requests. Explain why we have to do this in comments.

llvm-svn: 173776

llvm-svn: 173694

llvm-svn: 173687

llvm-svn: 173686

llvm-svn: 173681

llvm-svn: 173677

llvm-svn: 173676

llvm-svn: 173671

llvm-svn: 173668

llvm-svn: 173619

 - Also, fix the test this is guarding, which was backwards.

llvm-svn: 173465

llvm-svn: 173456

llvm-svn: 173451

llvm-svn: 173443

llvm-svn: 173441

llvm-svn: 173440

llvm-svn: 173348

llvm-svn: 173347

llvm-svn: 173346

llvm-svn: 173345

[Sanitizer] Add skeleton for InternalSymbolizer that can be used by providing callbacks __sanitizer_symbolize_{code,data}

llvm-svn: 173344

llvm-svn: 173336

llvm-svn: 173333

llvm-svn: 173332

llvm-svn: 173328

llvm-svn: 173327

This is used in symbolizer init.

llvm-svn: 173263

llvm-svn: 173261

[asan] initialize kHighMemEnd at startup (instead of at compile time) to simplify further changes for various address space layouts. Fix asan_allocator2 for PowerPC (tested on 44-bit address space)

llvm-svn: 173260

llvm-svn: 173255

llvm-svn: 173253

llvm-svn: 173251

llvm-svn: 173249

llvm-svn: 173161

llvm-svn: 173158

llvm-svn: 173157

llvm-svn: 173155

llvm-svn: 173154

A runtime call is used instead.
MSan will stop adding shadow checks on volatile stores soon.

llvm-svn: 173152

See https://code.google.com/p/address-sanitizer/issues/detail?id=131

llvm-svn: 173149