remove defensive malformed check in main loop

Author: InvalidPathException

bench.md

@@ -2,11 +2,13 @@ This file documents the coremark bench results to document performance improveme
 - ac6b813: avg ≈ 500 (introduced benchmarking without criterion)
 - 5f4af0c: avg = 529.773949, n = 20 (improved leb128 handling with unsafe)
     - we try to avoid unsafe code in module/validator/instance directly
-- current: avg = 810.367084, n = 20 (use a dense offset table instead of hashmap, better leb128, and cold path hinting)
+- 899f989: avg = 810.367084, n = 20 (improve leb128 handling, move sidetable to using arrays, label error creation as cold paths)
     - rust hashmaps are apparently very bad, this might be because of our memory access pattern, when we interpret the control op codes (corresponding to side table entries) they are kind of accessed sequentially, so even btreemap yields better results
     - current design: two-level indirection (one array covering all possible code indices and directing them to a densely packed side table)
     - we also try to not use nightly features... making error creation cold path is a really elegant solution in this regard
     - repr(C) for the SideTableEntry struct caused mysterious improvements, not sure if it is a fluke
+- current: avg = 855.71814, n = 20 (remove defensive malformed check in main loop)
+    - since the module is already validated at run time, there is no reason for the check to exist, it was a remnant of early development phase that lacked proper handling for some malformed modules
 
 
 Hardware Overview:

src/instance.rs

@@ -861,7 +861,6 @@ impl Instance {
         }}}
 
         loop {
-            if pc >= bytes.len() { return Err(Error::malformed(UNEXPECTED_END)); }
             match next_op!() {
                 0x00 => return Err(Error::trap(UNREACHABLE)),
                 0x01 | 0xbc | 0xbd | 0xbe | 0xbf => {} // nop and reinterprets (no-op on raw bits)