DWARF layout for bitfields is wrong when the bit offset is negative.

Some older versions of clang emitted bit offsets that were negative and these bitfields would have their bitfield-ness stripped off and it would cause a clang assertion in clang assertions were enabled. I updated the bitfield C test to make sure we don't regress.

<rdar://problem/21082998> 

llvm-svn: 267248

2 files changed, 22 insertions, 0 deletions

diff --git a/lldb/packages/Python/lldbsuite/test/lang/c/bitfields/TestBitfields.py b/lldb/packages/Python/lldbsuite/test/lang/c/bitfields/TestBitfields.py
index 60c1c0992d2..0afec0a3c1a 100644
--- a/lldb/packages/Python/lldbsuite/test/lang/c/bitfields/TestBitfields.py
+++ b/lldb/packages/Python/lldbsuite/test/lang/c/bitfields/TestBitfields.py
@@ -96,6 +96,14 @@ class BitfieldsTestCase(TestBase):
         self.expect("expr (more_bits.d)", VARIABLES_DISPLAYED_CORRECTLY,
             substrs = ['uint8_t', '\\0'])
 
+        self.expect("expr (packed.a)", VARIABLES_DISPLAYED_CORRECTLY, 
+            substrs = ['char', "'a'"])
+        self.expect("expr (packed.b)", VARIABLES_DISPLAYED_CORRECTLY, 
+            substrs = ['uint32_t', "10"])
+        self.expect("expr/x (packed.c)", VARIABLES_DISPLAYED_CORRECTLY, 
+            substrs = ['uint32_t', "7112233"])
+
+
     @add_test_categories(['pyapi'])
     @skipIfWindows # BitFields exhibit crashes in record layout on Windows (http://llvm.org/pr21800)
     def test_and_python_api(self):
diff --git a/lldb/packages/Python/lldbsuite/test/lang/c/bitfields/main.c b/lldb/packages/Python/lldbsuite/test/lang/c/bitfields/main.c
index 26c0176d759..236c926d81b 100644
--- a/lldb/packages/Python/lldbsuite/test/lang/c/bitfields/main.c
+++ b/lldb/packages/Python/lldbsuite/test/lang/c/bitfields/main.c
@@ -8,6 +8,7 @@
 //===----------------------------------------------------------------------===//
 #include <stdint.h>
 #include <stdio.h>
+
 int main (int argc, char const *argv[])
 {
     struct Bits
@@ -62,6 +63,19 @@ int main (int argc, char const *argv[])
     more_bits.c = 1;
     more_bits.d = 0;
 
+#pragma pack(1)
+    struct PackedBits
+    {
+        char a;
+    	uint32_t b : 5,
+                 c : 27;
+    };
+#pragma pack()  
+    struct PackedBits packed;
+    packed.a = 'a';
+    packed.b = 10;
+    packed.c = 0x7112233;
+
     return 0;               //// Set break point at this line.
 
 }