[llvm] [openmp] [libc] [compiler-rt] [lldb] [mlir] [flang] [libcxx] [clang] [hwasan] Classify stack overflow, and use after scope (PR #76133)

[Florian Mayer via cfe-commits]

================
@@ -221,29 +221,55 @@ static void PrintStackAllocations(const StackAllocationsRingBuffer *sa,
       for (LocalInfo &local : frame.locals) {
         if (!local.has_frame_offset || !local.has_size || !local.has_tag_offset)
           continue;
+        if (!(local.name && internal_strlen(local.name)) &&
+            !(local.function_name && internal_strlen(local.name)) &&
+            !(local.decl_file && internal_strlen(local.decl_file)))
+          continue;
         tag_t obj_tag = base_tag ^ local.tag_offset;
         if (obj_tag != addr_tag)
           continue;
-        // Calculate the offset from the object address to the faulting
-        // address. Because we only store bits 4-19 of FP (bits 0-3 are
-        // guaranteed to be zero), the calculation is performed mod 2^20 and may
-        // harmlessly underflow if the address mod 2^20 is below the object
-        // address.
-        uptr obj_offset =
-            (untagged_addr - fp - local.frame_offset) & (kRecordFPModulus - 1);
-        if (obj_offset >= local.size)
-          continue;
+        uptr local_beg = (fp + local.frame_offset) |
----------------
fmayer wrote:

 I am confused by this. Could you add a comment as on the LHS? Why isn't the `local_beg` not just `fp + local.frame_offset`?

https://github.com/llvm/llvm-project/pull/76133