rose: rework storage of extra lookaround information

- remove explicit lookaround table from bytecode
- make the RoseInstr responsible for adding required info to blob

src/rose/rose_build_engine_blob.h

@@ -34,6 +34,7 @@
 #include "ue2common.h"
 #include "util/alloc.h"
 #include "util/bytecode_ptr.h"
+#include "util/charreach.h"
 #include "util/container.h"
 #include "util/multibit_build.h"
 #include "util/noncopyable.h"
@@ -45,6 +46,21 @@
 
 namespace ue2 {
 
+class RoseEngineBlob;
+
+struct lookaround_info : noncopyable {
+    u32 get_offset_of(const std::vector<std::vector<CharReach>> &look,
+                      RoseEngineBlob &blob);
+    u32 get_offset_of(const std::vector<CharReach> &reach,
+                      RoseEngineBlob &blob);
+    u32 get_offset_of(const std::vector<s8> &look, RoseEngineBlob &blob);
+
+private:
+    unordered_map<std::vector<std::vector<CharReach>>, u32> multi_cache;
+    unordered_map<std::vector<s8>, u32> lcache;
+    unordered_map<std::vector<CharReach>, u32> rcache;
+};
+
 class RoseEngineBlob : noncopyable {
 public:
     /** \brief Base offset of engine_blob in the Rose engine bytecode. */
@@ -133,6 +149,8 @@ public:
         copy_bytes((char *)engine + base_offset, blob);
     }
 
+    lookaround_info lookaround_cache;
+
 private:
     void pad(size_t align) {
         assert(ISALIGNED_N(base_offset, align));