[compiler-rt] [sanitizer] Warn if allocator size exceeds max user virtual address (PR #152428)

[Florian Mayer via llvm-commits]

================
@@ -113,6 +113,23 @@ class SizeClassAllocator64 {
   // ~(uptr)0.
   void Init(s32 release_to_os_interval_ms, uptr heap_start = 0) {
     uptr TotalSpaceSize = kSpaceSize + AdditionalSize();
+
+    uptr MaxAddr = GetMaxUserVirtualAddress();
+    // VReport does not call the sanitizer allocator.
+    VReport(3, "Max user virtual address: 0x%zx\n", MaxAddr);
+    VReport(3, "Total space size for primary allocator: 0x%zx\n",
+            TotalSpaceSize);
+    // TODO: hypothetical edge case: on >48-bit VMA systems, Linux by default
----------------
fmayer wrote:

it's not immediately clear what there is TO DO

https://github.com/llvm/llvm-project/pull/152428