compress type info of zeroinitializers in ta2

src/parseTools.js

@@ -1265,6 +1265,9 @@ function makePointer(slab, pos, allocator, type) {
     de = dedup(evaled);
     if (de.length === 1 && de[0] === 0) {
       slab = types.length;
+      if (USE_TYPED_ARRAYS == 2) {
+        types = ['i8']; //  if data is zeros, we don't need type info
+      }
     }
     // TODO: if not all zeros, at least filter out items with type === 0. requires cleverness to know how to skip at runtime though. also
     //       be careful of structure padding

tests/runner.py

@@ -2466,6 +2466,30 @@ c5,de,15,8a
           '''
         self.do_run(src, '*70,97,15,3,3029,90*')
 
+    def test_bigarray(self):
+      if self.emcc_args is None: return self.skip('need ta2 to compress type data on zeroinitializers')
+
+      # avoid "array initializer too large" errors
+      src = r'''
+        #include <stdio.h>
+        #include <assert.h>
+
+        #define SIZE (1024*100)
+        struct Struct {
+          char x;
+          int y;
+        };
+        Struct buffy[SIZE];
+
+        int main() {
+          for (int i = 0; i < SIZE; i++) { assert(buffy[i].x == 0 && buffy[i].y == 0); } // we were zeroinitialized
+          for (int i = 0; i < SIZE; i++) { buffy[i].x = i*i; buffy[i].y = i*i*i; } // we can save data
+          printf("*%d*\n", buffy[SIZE/3].x);
+          return 0;
+        }
+        '''
+      self.do_run(src, '*57*')
+
     def test_mod_globalstruct(self):
         src = '''
           #include <stdio.h>