Rewrite parser as recursive descent (#591)

* Remove Bison dependency
* Remove pre-generated parser files
* Rename build config from no-re2c-bison to no-re2c
* Add a simple make_unique implementation
* Move handling of module bindings into ir.cc
* Simplify lexer
  - Remove lookahead, the parser handles this now
  - Unify Token/LexerToken, it only contains terminal values now
  - Refactor setting token type and value into one function (e.g.
    LITERAL, RETURN => RETURN_LITERAL)
* New Parser
  - Uses two tokens of lookahead (use Peek(0) or Peek(1))
  - Consume() consumes one token of any kind
  - Match(t) consumes the current token if it matches
  - PeekMatch(t) returns true iff the token matches, but doesn't consume
  - Basic error synchronization; plenty of room for improvement here

1 files changed, 7 insertions, 2 deletions

diff --git a/src/circular-array.h b/src/circular-array.h
index 3787cbdd..265410e8 100644
--- a/src/circular-array.h
+++ b/src/circular-array.h
@@ -18,6 +18,9 @@
 #define WABT_CIRCULAR_ARRAY_H_
 
 #include <array>
+#include <cassert>
+#include <cstddef>
+#include <type_traits>
 
 namespace wabt {
 
@@ -33,8 +36,10 @@ class CircularArray {
   typedef const value_type& const_reference;
   typedef size_t size_type;
   typedef ptrdiff_t difference_type;
+
   CircularArray() : size_(0), front_(0), mask_(kCapacity - 1) {
-    assert(kCapacity && ((kCapacity & (kCapacity - 1)) == 0));
+    static_assert(kCapacity && ((kCapacity & (kCapacity - 1)) == 0),
+                  "Capacity must be a power of 2.");
   }
 
   reference at(size_type index) {
@@ -86,7 +91,7 @@ class CircularArray {
     --size_;
   }
 
-  void push_back(value_type& value) {
+  void push_back(const value_type& value) {
     assert(size_ < kCapacity);
     contents_[position(size_++)] = value;
   }