[PATCH] D38358: [analyzer] Fix autodetection of getSVal()'s type argument.

[Devin Coughlin via Phabricator via cfe-commits]

dcoughlin added a comment.

This is such a nasty bug! It is great to see a fix. I have two comments inline, one of which is just a nit.



================
Comment at: lib/StaticAnalyzer/Core/RegionStore.cpp:1404
+          // When trying to dereference a void pointer, read the first byte.
+          T = Ctx.CharTy;
+        }
----------------
Nit: It seems a bit odd to read the first byte here since (unless I'm misunderstanding) this would never be triggered by actual C semantics, only by a checker. Did you consider just returning UnknownVal() in this case?


================
Comment at: lib/StaticAnalyzer/Core/RegionStore.cpp:1408
     }
+    assert(!T.isNull() && "Unable to auto-detect binding type!");
+    assert(!T->isVoidType() && "Attempted to retrieve a void value!");
----------------
I think you missed handling the AllocaRegion case from the old version in your new version. This means the assert will fire on the following when core.alpha is enabled:
```
void foo(void *dest) {
  void *src = __builtin_alloca(5);
  memcpy(dest, src, 1);
}
```


https://reviews.llvm.org/D38358