@DAWN-390 fixed issue with sbrk not clearing between actions, and added page...

@DAWN-390 fixed issue with sbrk not clearing between actions, and added page resizing to cache checkin to ensure page size goes back to default

libraries/chain/include/eosio/chain/wasm_interface_private.hpp

@@ -17,15 +17,23 @@ using wasm_double = boost::multiprecision::cpp_dec_float_50;
 
 struct wasm_cache::entry {
    entry(ModuleInstance *instance, Module *module)
-      : instance(instance), module(module) {}
+      : instance(instance), module(module) 
+   {
+   }
 
-   ModuleInstance *instance;
-   Module *module;
+   ModuleInstance* instance;
+   Module* module;
 };
 
 struct wasm_context {
-   wasm_cache::entry &code;
-   apply_context &context;
+   wasm_context(wasm_cache::entry &code, apply_context& ctx) : code(code), context(ctx)
+   {
+      //initialize to minimum bytes and limit this to 32 bit space
+      sbrk_bytes = (1 << IR::numBytesPerPageLog2) > UINT32_MAX ? UINT32_MAX : 1 << IR::numBytesPerPageLog2;
+   }
+   wasm_cache::entry& code;
+   apply_context& context;
+   uint32_t sbrk_bytes;
 };
 
 struct wasm_interface_impl {

libraries/chain/wasm_interface.cpp

@@ -342,18 +342,18 @@ namespace eosio { namespace chain {
    wasm_cache::~wasm_cache() = default;
 
    wasm_cache::entry &wasm_cache::checkout( const digest_type& code_id, const char* wasm_binary, size_t wasm_binary_size ) {
-      // see if there is an avaialble entry in the cache
+      // see if there is an available entry in the cache
       auto result = _my->try_fetch_entry(code_id);
-
       if (result) {
          return (*result).get();
       }
-
       return _my->fetch_entry(code_id, wasm_binary, wasm_binary_size);
    }
 
 
    void wasm_cache::checkin(const digest_type& code_id, entry& code ) {
+      auto default_mem = Runtime::getDefaultMemory(code.instance);
+      Runtime::shrinkMemory(default_mem, Runtime::getMemoryNumPages(default_mem) - 1);
       _my->return_entry(code_id, code);
    }
 
@@ -622,10 +622,12 @@ DEFINE_INTRINSIC_FUNCTION0(env,checktime,checktime,none) {
 class context_aware_api {
    public:
       context_aware_api(wasm_interface& wasm)
-      :context(intrinsics_accessor::get_context(wasm).context), code(intrinsics_accessor::get_context(wasm).code)
+      :context(intrinsics_accessor::get_context(wasm).context), code(intrinsics_accessor::get_context(wasm).code),
+       sbrk_bytes(intrinsics_accessor::get_context(wasm).sbrk_bytes)
       {}
 
    protected:
+      uint32_t&          sbrk_bytes;
       wasm_cache::entry& code;
       apply_context&     context;
 };
@@ -811,8 +813,7 @@ class db_index_api : public context_aware_api {
 class memory_api : public context_aware_api {
    public:
       using context_aware_api::context_aware_api;
-
-
+     
       char* memcpy( array_ptr<char> dest, array_ptr<const char> src, size_t length) {
          return (char *)::memcpy(dest, src, length);
       }
@@ -827,27 +828,25 @@ class memory_api : public context_aware_api {
 
       uint32_t sbrk(int num_bytes) {
          // TODO: omitted checktime function from previous version of sbrk, may need to be put back in at some point
-         constexpr uint32_t NBPPL2         = IR::numBytesPerPageLog2;
-         constexpr uint32_t max_mem        = 1024 * 1024;
+         constexpr uint32_t NBPPL2  = IR::numBytesPerPageLog2;
+         constexpr uint32_t MAX_MEM = 1024 * 1024;
+
          const auto         default_mem    = Runtime::getDefaultMemory(code.instance);
          const uint32_t     num_pages      = Runtime::getMemoryNumPages(default_mem);
-         // limit this min to 32 bit space 
          const uint32_t     min_bytes      = (num_pages << NBPPL2) > UINT32_MAX ? UINT32_MAX : num_pages << NBPPL2;
-         static uint32_t    _num_bytes     = min_bytes;
-         const uint32_t     prev_num_bytes = _num_bytes;
-
-
+         const uint32_t     prev_num_bytes = sbrk_bytes; //_num_bytes;
+         
          // round the absolute value of num_bytes to an alignment boundary
          num_bytes = (num_bytes + 7) & ~7;
 
-         if ((num_bytes > 0) && (prev_num_bytes > (max_mem - num_bytes)))  // test if allocating too much memory (overflowed)
+         if ((num_bytes > 0) && (prev_num_bytes > (MAX_MEM - num_bytes)))  // test if allocating too much memory (overflowed)
             throw eosio::chain::page_memory_error();
          else if ((num_bytes < 0) && (prev_num_bytes < (min_bytes - num_bytes))) // test for underflow
             throw eosio::chain::page_memory_error(); 
 
          // update the number of bytes allocated, and compute the number of pages needed
-         _num_bytes += num_bytes;
-         const uint32_t num_desired_pages = (_num_bytes + IR::numBytesPerPage - 1) >> NBPPL2;
+         sbrk_bytes += num_bytes;
+         const uint32_t num_desired_pages = (sbrk_bytes + IR::numBytesPerPage - 1) >> NBPPL2;
 
          // grow or shrink the memory to the desired number of pages
          if (num_desired_pages > num_pages)
@@ -856,7 +855,7 @@ class memory_api : public context_aware_api {
             Runtime::shrinkMemory(default_mem, num_pages - num_desired_pages);
 
          return prev_num_bytes;
-   }
+      }
 };
 
 class transaction_api : public context_aware_api {