proper support for packed structs

3 files changed, 36 insertions, 2 deletions

diff --git a/src/intertyper.js b/src/intertyper.js
index fe4eb929..efeba90a 100644
--- a/src/intertyper.js
+++ b/src/intertyper.js
@@ -315,11 +315,13 @@ function intertyper(data, parseFunctions, baseLineNum) {
       }
       if (item.tokens[2].text == 'type') {
         var fields = [];
+        var packed = false;
         if (Runtime.isNumberType(item.tokens[3].text)) {
           // Clang sometimes has |= i32| instead of |= { i32 }|
           fields = [item.tokens[3].text];
         } else if (item.tokens[3].text != 'opaque') {
-          if (item.tokens[3].type == '<') { // type <{ i8 }> - TODO: check spec
+          if (item.tokens[3].type == '<') {
+            packed = true;
             item.tokens[3] = tokenizer.processItem({ lineText: '{ ' + item.tokens[3].item.tokens[0].text + ' }' }, true).tokens[0];
           }
           var subTokens = item.tokens[3].tokens;
@@ -335,6 +337,7 @@ function intertyper(data, parseFunctions, baseLineNum) {
           intertype: 'type',
           name_: item.tokens[0].text,
           fields: fields,
+          packed: packed,
           lineNum: item.lineNum
         }];
       } else {
diff --git a/src/runtime.js b/src/runtime.js
index acd5ed8d..6c3d630c 100644
--- a/src/runtime.js
+++ b/src/runtime.js
@@ -113,7 +113,7 @@ Runtime = {
         dprint('Unclear type in struct: ' + field + ', in ' + type.name_);
         assert(0);
       }
-      alignSize = Math.min(alignSize, QUANTUM_SIZE);
+      alignSize = type.packed ? 1 : Math.min(alignSize, QUANTUM_SIZE);
       type.alignSize = Math.max(type.alignSize, alignSize);
       var curr = Runtime.alignMemory(type.flatSize, alignSize); // if necessary, place this on aligned memory
       type.flatSize = curr + size;
diff --git a/tests/runner.py b/tests/runner.py
index d7a6409e..635a4d0f 100644
--- a/tests/runner.py
+++ b/tests/runner.py
@@ -1228,6 +1228,37 @@ if 'benchmark' not in sys.argv:
           '''
         self.do_test(src, '*96,97,98,101,101*')
 
+    def test_pack(self):
+        src = '''
+          #include <stdio.h>
+          #include <string.h>
+
+          #pragma pack(push,1)
+          typedef struct header
+          {                           
+              unsigned char  id;
+              unsigned short colour;
+              unsigned char  desc;
+          } header;
+          #pragma pack(pop)
+
+          typedef struct fatheader
+          {                           
+              unsigned char  id;
+              unsigned short colour;
+              unsigned char  desc;
+          } fatheader;
+
+          int main( int argc, const char *argv[] ) {
+            header h, *ph = 0;
+            fatheader fh, *pfh = 0;
+            printf("*%d,%d,%d*\\n", sizeof(header), (int)((int)&h.desc - (int)&h.id), (int)(&ph[1])-(int)(&ph[0]));
+            printf("*%d,%d,%d*\\n", sizeof(fatheader), (int)((int)&fh.desc - (int)&fh.id), (int)(&pfh[1])-(int)(&pfh[0]));
+            return 0;
+          }
+          '''
+        self.do_test(src, '*4,3,4*\n*6,4,6*')
+
     def test_varargs(self):
         src = '''
           #include <stdio.h>