add emscripten_align typedefs for #2378

Author: kripken

system/include/emscripten/emscripten.h

@@ -18,6 +18,32 @@ extern "C" {
 #include <SDL/SDL.h> /* for SDL_Delay in async_call */
 #endif
 
+
+/* Typedefs */
+
+/*
+ * Unaligned types, helpful to force LLVM to emit unaligned
+ * loads/stores in places in your code where SAFE_HEAP found
+ * an unaligned operation. (It's better to avoid unaligned
+ * operations, but if you are reading from a packed stream of
+ * bytes or such, these types may be useful.)
+ */
+
+typedef short __attribute__((aligned(1))) emscripten_align1_short;
+
+typedef int __attribute__((aligned(2))) emscripten_align2_int;
+typedef int __attribute__((aligned(1))) emscripten_align1_int;
+
+typedef float __attribute__((aligned(2))) emscripten_align2_float;
+typedef float __attribute__((aligned(1))) emscripten_align1_float;
+
+typedef double __attribute__((aligned(4))) emscripten_align4_double;
+typedef double __attribute__((aligned(2))) emscripten_align2_double;
+typedef double __attribute__((aligned(1))) emscripten_align1_double;
+
+
+/* Functions */
+
 /*
  * Convenient syntax for inline assembly/js. Allows stuff like
  *

tests/core/test_set_align.c

@@ -0,0 +1,50 @@
+
+#include <stdio.h>
+#include <emscripten.h>
+ 
+volatile char data[16];
+ 
+__attribute__((noinline)) void *get_aligned(int align)
+{
+  char *ptr = (char*)(((int)(data + 7)) & ~7); // Make 8-byte aligned
+  ptr += align; // Now 'align' aligned
+  return (void*)ptr;
+}
+ 
+int main()
+{
+  emscripten_align4_double *d4 = (emscripten_align4_double*)get_aligned(4);
+  *d4 = 17.0;
+  printf("addr: %d, value: %f\n", ((int)d4) % 8, *d4);
+
+  emscripten_align2_double *d2 = (emscripten_align2_double*)get_aligned(2);
+  *d2 = 18.0;
+  printf("addr: %d, value: %f\n", ((int)d2) % 8, *d2);
+
+  emscripten_align1_double *d1 = (emscripten_align1_double*)get_aligned(1);
+  *d1 = 19.0;
+  printf("addr: %d, value: %f\n", ((int)d1) % 8, *d1);
+
+  emscripten_align2_float *f2 = (emscripten_align2_float*)get_aligned(2);
+  *f2 = 20.0;
+  printf("addr: %d, value: %f\n", ((int)f2) % 4, *f2);
+
+  emscripten_align1_float *f1 = (emscripten_align1_float*)get_aligned(1);
+  *f1 = 21.0;
+  printf("addr: %d, value: %f\n", ((int)f1) % 4, *f1);
+
+  emscripten_align2_int *i2 = (emscripten_align2_int*)get_aligned(2);
+  *i2 = 22;
+  printf("addr: %d, value: %d\n", ((int)i2) % 4, *i2);
+
+  emscripten_align1_int *i1 = (emscripten_align1_int*)get_aligned(1);
+  *i1 = 23;
+  printf("addr: %d, value: %d\n", ((int)i1) % 4, *i1);
+
+  emscripten_align1_short *s1 = (emscripten_align1_short*)get_aligned(1);
+  *s1 = 24;
+  printf("addr: %d, value: %d\n", ((int)s1) % 4, (int)*s1);
+
+  return 0;
+}
+

tests/core/test_set_align.out

@@ -0,0 +1,8 @@
+addr: 4, value: 17.000000
+addr: 2, value: 18.000000
+addr: 1, value: 19.000000
+addr: 2, value: 20.000000
+addr: 1, value: 21.000000
+addr: 2, value: 22
+addr: 1, value: 23
+addr: 1, value: 24

tests/test_core.py

@@ -1980,6 +1980,15 @@ def test_llvm_used(self):
 
     self.do_run_from_file(src, output)
 
+  def test_set_align(self):
+    if self.run_name == 'slow2asm': return self.skip('FIXME in slow2asm')
+
+    Settings.SAFE_HEAP = 1
+
+    test_path = path_from_root('tests', 'core', 'test_set_align')
+    src, output = (test_path + s for s in ('.c', '.out'))
+    self.do_run_from_file(src, output)
+
   def test_emscripten_api(self):
       #if Settings.MICRO_OPTS or Settings.RELOOP or Building.LLVM_OPTS: return self.skip('FIXME')