add some support for le32=2 mode, where varargs is just 4-byte aligned

Author: kripken

emscripten.py

@@ -755,6 +755,7 @@ def emscript_fast(infile, settings, outfile, libraries=[], compiler_engine=None,
   if DEBUG:
     shutil.copyfile(temp2, os.path.join(shared.CANONICAL_TEMP_DIR, 'temp2.bc'))
     shared.jsrun.timeout_run(subprocess.Popen([os.path.join(shared.PNACL_ROOT, 'llvm-dis'), 'temp2.bc', '-o', 'temp2.ll']))
+  #temp2 = temp1
 
   if DEBUG: logging.debug('  ..3..')
   temp3 = temp_files.get('.3.bc').name
@@ -796,6 +797,10 @@ def emscript_fast(infile, settings, outfile, libraries=[], compiler_engine=None,
   # Integrate info from backend
   settings['DEFAULT_LIBRARY_FUNCS_TO_INCLUDE'] = settings['DEFAULT_LIBRARY_FUNCS_TO_INCLUDE'] + metadata['declares']
 
+  # Settings changes
+  assert settings['TARGET_LE32'] == 1
+  settings['TARGET_LE32'] = 2
+
   # Save settings to a file to work around v8 issue 1579
   settings_file = temp_files.get('.txt').name
   def save_settings():

src/library.js

@@ -1855,7 +1855,11 @@ LibraryManager.library = {
       //       int x = 4; printf("%c\n", (char)x);
       var ret;
       if (type === 'double') {
+#if TARGET_LE32 == 2
+        ret = {{{ makeGetValue('varargs', 'argIndex', 'double', undefined, undefined, true, 4) }}};
+#else
         ret = {{{ makeGetValue('varargs', 'argIndex', 'double', undefined, undefined, true) }}};
+#endif
 #if USE_TYPED_ARRAYS == 2
       } else if (type == 'i64') {
 
@@ -1876,7 +1880,11 @@ LibraryManager.library = {
         type = 'i32'; // varargs are always i32, i64, or double
         ret = {{{ makeGetValue('varargs', 'argIndex', 'i32', undefined, undefined, true) }}};
       }
+#if TARGET_LE32 == 2
+      argIndex += Runtime.getNativeFieldSize(type);
+#else
       argIndex += Math.max(Runtime.getNativeFieldSize(type), Runtime.getAlignSize(type, null, true));
+#endif
       return ret;
     }
 

src/settings.js

@@ -23,7 +23,8 @@ var QUANTUM_SIZE = 4; // This is the size of an individual field in a structure.
                       // Changing this from the default of 4 is deprecated.
 
 var TARGET_X86 = 0;  // For i386-pc-linux-gnu
-var TARGET_LE32 = 1; // For le32-unknown-nacl
+var TARGET_LE32 = 1; // For le32-unknown-nacl. 1 is normal, 2 is for the fastcomp llvm
+                     // backend using pnacl abi simplification
 
 var CORRECT_SIGNS = 1; // Whether we make sure to convert unsigned values to signed values.
                        // Decreases performance with additional runtime checks. Might not be