Add memoryLimit

Author: vshymanskyy

examples/Wasm_Blink/Wasm_Blink.ino

@@ -6,16 +6,21 @@
 
 #include <wasm3.h>
 
-// You can redefine the default LED pin here, if needed
-//#define LED_BUILTIN   D7
+/*
+ * Configuration
+ */
 
-#ifndef LED_BUILTIN
+// Redefine the default LED pin here, if needed
 #define LED_BUILTIN   13
-#endif
 
 #define WASM_STACK_SLOTS  1024
 #define NATIVE_STACK_SIZE 32768
 
+// For devices that cannot allocate a 64KiB wasm page
+#if defined(ESP8266) || defined(PARTICLE) //...
+#define WASM_MEMORY_LIMIT 2048
+#endif
+
 /*
  * WebAssembly app
  *
@@ -158,6 +163,10 @@ void wasm_task(void*)
     IM3Runtime runtime = m3_NewRuntime (env, WASM_STACK_SLOTS, NULL);
     if (!runtime) FATAL("NewRuntime", "failed");
 
+#ifdef WASM_MEMORY_LIMIT
+    runtime->memoryLimit = WASM_MEMORY_LIMIT;
+#endif
+
     IM3Module module;
     result = m3_ParseModule (env, &module, app_wasm, app_wasm_len-1);
     if (result) FATAL("ParseModule", result);

src/m3_env.c

@@ -291,6 +291,12 @@ M3Result  ResizeMemory  (IM3Runtime io_runtime, u32 i_numPages)
     if (numPagesToAlloc <= memory->maxPages)
     {
         size_t numPageBytes = numPagesToAlloc * d_m3MemPageSize;
+
+        // Limit the amount of memory that gets allocated
+        if (io_runtime->memoryLimit) {
+            numPageBytes = min(numPageBytes, io_runtime->memoryLimit);
+        }
+
         size_t numBytes = numPageBytes + sizeof (M3MemoryHeader);
 
         size_t numPreviousBytes = memory->numPages * d_m3MemPageSize;

src/m3_env.h

@@ -223,6 +223,7 @@ typedef struct M3Runtime
     M3Result                runtimeError;
 
     M3Memory                memory;
+    u32                     memoryLimit;
 
     M3ErrorInfo             error;
 #if defined(d_m3VerboseLogs)