Move the note about C/C++ undefined behavior into CAndC++.md.

The text fits better there, and this also tidies up Nondeterminism.md.

1 files changed, 19 insertions, 0 deletions

diff --git a/CAndC++.md b/CAndC++.md
index b11a363..97653d8 100644
--- a/CAndC++.md
+++ b/CAndC++.md
@@ -53,6 +53,25 @@ undefined behavior in C or C++ are still bugs when compiling for WebAssembly
 optimizers still assume that undefined behavior won't occur, so such bugs
 can still lead to surprising behavior.
 
+For example, while unaligned memory access is
+[fully defined](AstSemantics.md#Alignment) in WebAssembly, C and C++ compilers
+make no guarantee that a (non-packed) unaligned memory access at the source
+level is harmlessly translated into an unaligned memory access in WebAssembly.
+And in practice, popular C and C++ compilers do optimize on the assumption that
+alignment rules are followed, meaning that they don't always preserve program
+behavior otherwise.
+
+On WebAssembly, the primary invariants
+[are always maintained](Nondeterminism.md). Demons can't actually fly out your
+nose, as that would constitute an escape from the sandbox. And, callstacks can't
+become corrupted.
+
+Other than that, programs which invoke undefined behavior at the source language
+level may be compiled into WebAssembly programs which do anything else,
+including corrupting the contents of the application heap, calling APIs with
+arbitrary parameters, hanging, trapping, or consuming arbitrary amounts of
+resources (within the limits).
+
 [Tools are being developed and ported](Tooling.md) to help developers find
 and fix such bugs in their code.