[Lldb-commits] [PATCH] D71487: [LLDB] Fix address computation for inline function

[Greg Clayton via Phabricator via lldb-commits]

clayborg added a comment.

It is sad that we can't tell if a DW_AT_low_pc with a value of zero is valid or not. Some shared libraries might be able to have a function at address zero, so we need to be careful here. My proposed fix above will check the section that contains the low PC to see if it has execute permissions, so that should cover all cases (executables and shared libraries). Not sure if there is more we can do.



================
Comment at: lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp:2285
 
-    if (addr.IsValid()) {
+    if (addr.IsSectionOffset()) {
       sc_list.Append(sc);
----------------
Checking if the address is section offset might not be enough. All darwin systems have a __PAGEZERO segment that covers the first 4GB for 64 bit files and the first 4096 bytes for 32 bit fiules. This section has no read, no write no execute permissions. So maybe grab the section and verify it has read + execute permissions? That way data symbol matches won't trigger. 

```
if (auto section_sp = addr.GetSection()) {
  if (section_sp->GetPermissions() & ePermissionsExecutable) {
    sc_list.Append(sc);
    return true;
  }
}
```


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D71487/new/

https://reviews.llvm.org/D71487