Add some Rust allocation functions to TargetLibraryInfo + MemoryBuiltins

Original patch by Nathaniel Theis

include/llvm/Analysis/TargetLibraryInfo.def

@@ -195,6 +195,12 @@ TLI_DEFINE_STRING_INTERNAL("__memmove_chk")
 /// void *__memset_chk(void *s, char v, size_t n, size_t s1size);
 TLI_DEFINE_ENUM_INTERNAL(memset_chk)
 TLI_DEFINE_STRING_INTERNAL("__memset_chk")
+/// void *__rust_allocate(size_t size, size_t align)
+TLI_DEFINE_ENUM_INTERNAL(rust_allocate)
+TLI_DEFINE_STRING_INTERNAL("__rust_allocate")
+/// void __rust_deallocate(void *ptr, size_t size, size_t align)
+TLI_DEFINE_ENUM_INTERNAL(rust_deallocate)
+TLI_DEFINE_STRING_INTERNAL("__rust_deallocate")
 /// double __sincospi_stret(double x);
 TLI_DEFINE_ENUM_INTERNAL(sincospi_stret)
 TLI_DEFINE_STRING_INTERNAL("__sincospi_stret")

lib/Analysis/MemoryBuiltins.cpp

@@ -74,7 +74,8 @@ static const AllocFnsTy AllocationFnData[] = {
   {LibFunc::realloc,             ReallocLike, 2, 1,  -1},
   {LibFunc::reallocf,            ReallocLike, 2, 1,  -1},
   {LibFunc::strdup,              StrDupLike,  1, -1, -1},
-  {LibFunc::strndup,             StrDupLike,  2, 1,  -1}
+  {LibFunc::strndup,             StrDupLike,  2, 1,  -1},
+  {LibFunc::rust_allocate,       MallocLike,  2, 0,  -1}
   // TODO: Handle "int posix_memalign(void **, size_t, size_t)"
 };
 
@@ -323,6 +324,8 @@ const CallInst *llvm::isFreeCall(const Value *I, const TargetLibraryInfo *TLI) {
            TLIFn == LibFunc::msvc_delete_array_ptr32_nothrow || // delete[](void*, nothrow)
            TLIFn == LibFunc::msvc_delete_array_ptr64_nothrow)   // delete[](void*, nothrow)
     ExpectedNumParams = 2;
+  else if (TLIFn == LibFunc::rust_deallocate)
+    ExpectedNumParams = 3;
   else
     return nullptr;