fix structure size when it has a [0 x ..] at the end - that should add nothing

3 files changed, 35 insertions, 4 deletions

diff --git a/src/runtime.js b/src/runtime.js
index 684f11e7..062066af 100644
--- a/src/runtime.js
+++ b/src/runtime.js
@@ -201,14 +201,24 @@ var Runtime = {
     type.alignSize = 0;
     var diffs = [];
     var prev = -1;
+    var index = 0;
     type.flatIndexes = type.fields.map(function(field) {
+      index++;
       var size, alignSize;
       if (Runtime.isNumberType(field) || Runtime.isPointerType(field)) {
         size = Runtime.getNativeTypeSize(field); // pack char; char; in structs, also char[X]s.
         alignSize = Runtime.getAlignSize(field, size);
       } else if (Runtime.isStructType(field)) {
-        size = Types.types[field].flatSize;
-        alignSize = Runtime.getAlignSize(null, Types.types[field].alignSize);
+        if (field[1] === '0') {
+          // this is [0 x something]. When inside another structure like here, it must be at the end,
+          // and it adds no size
+          assert(index === type.fields.length);
+          size = 0;
+          alignSize = 0;
+        } else {
+          size = Types.types[field].flatSize;
+          alignSize = Runtime.getAlignSize(null, Types.types[field].alignSize);
+        }
       } else if (field[0] == 'b') {
         // bN, large number field, like a [N x i8]
         size = field.substr(1)|0;
@@ -218,8 +228,12 @@ var Runtime = {
       }
       if (type.packed) alignSize = 1;
       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;
+      if (size > 0) {
+        var curr = Runtime.alignMemory(type.flatSize, alignSize); // if necessary, place this on aligned memory
+        type.flatSize = curr + size;
+      } else {
+        curr = prev;
+      }
       if (prev >= 0) {
         diffs.push(curr-prev);
       }
diff --git a/tests/cases/zeroembedded.ll b/tests/cases/zeroembedded.ll
new file mode 100644
index 00000000..c1ffa212
--- /dev/null
+++ b/tests/cases/zeroembedded.ll
@@ -0,0 +1,16 @@
+; a.ll
+%struct.pypy_str = type { i32, [0 x i8] }
+%struct.pypy_strval = type { i32, [13 x i8] }
+
+@pypy_g_strval = global %struct.pypy_strval { i32 13, [13 x i8] c"hello world\0A\00" }
+
+declare i32 @printf(i8*, ...)
+
+define i32 @main(i32 %argc, i8** nocapture %argv)  {
+  %1 = bitcast %struct.pypy_strval* @pypy_g_strval to %struct.pypy_str*
+  %2 = getelementptr inbounds %struct.pypy_str* %1, i32 1
+  %3 = bitcast %struct.pypy_str* %2 to i8*
+  call i32 (i8*, ...)* @printf(i8* %3)
+  ret i32 0
+}
+
diff --git a/tests/cases/zeroembedded.txt b/tests/cases/zeroembedded.txt
new file mode 100644
index 00000000..3b18e512
--- /dev/null
+++ b/tests/cases/zeroembedded.txt
@@ -0,0 +1 @@
+hello world