From e06a75f4c8ea30b6a99d5aa1dce5feda64da09c6 Mon Sep 17 00:00:00 2001
From: Daniel Dunbar <daniel@zuster.org>
Date: Wed, 11 Mar 2009 22:05:26 +0000
Subject: [PATCH] x86_32 ABI: Don't try and expand structures with bitfields. 
 - This is an ABI incompatiblity, but this is not likely to be a huge    deal
 in practice. For now we at least generate self consistent code    instead of
 crashing.  - <rdar://problem/6657601> x86-32 ABI: Bitfields in small
 structures    are not passed correctly

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@66713 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/CGCall.cpp          | 14 +++----
 test/CodeGen/x86_32-arguments.c | 67 +++++++++++++++++++++++++++++++++
 2 files changed, 74 insertions(+), 7 deletions(-)
 create mode 100644 test/CodeGen/x86_32-arguments.c

diff --git a/lib/CodeGen/CGCall.cpp b/lib/CodeGen/CGCall.cpp
index e9ac5c9751..9e52cbb79c 100644
--- a/lib/CodeGen/CGCall.cpp
+++ b/lib/CodeGen/CGCall.cpp
@@ -215,14 +215,14 @@ static bool areAllFields32Or64BitBasicType(const RecordDecl *RD,
     if (!is32Or64BitBasicType(FD->getType(), Context))
       return false;
     
-    // If this is a bit-field we need to make sure it is still a
-    // 32-bit or 64-bit type.
-    if (Expr *BW = FD->getBitWidth()) {
-      unsigned Width = BW->getIntegerConstantExprValue(Context).getZExtValue();
-      if (Width <= 16)
-        return false;
-    }
+    // FIXME: Reject bitfields wholesale; there are two problems, we
+    // don't know how to expand them yet, and the predicate for
+    // telling if a bitfield still counts as "basic" is more
+    // complicated than what we were doing previously.
+    if (FD->isBitField())
+      return false;
   }
+
   return true;
 }
 
diff --git a/test/CodeGen/x86_32-arguments.c b/test/CodeGen/x86_32-arguments.c
new file mode 100644
index 0000000000..339f16e0f7
--- /dev/null
+++ b/test/CodeGen/x86_32-arguments.c
@@ -0,0 +1,67 @@
+// RUN: clang -triple i386-unknown-unknown -emit-llvm -o %t %s &&
+// RUN: grep 'define signext i8 @f0()' %t &&
+// RUN: grep 'define signext i16 @f1()' %t &&
+// RUN: grep 'define i32 @f2()' %t &&
+// RUN: grep 'define float @f3()' %t &&
+// RUN: grep 'define double @f4()' %t &&
+// RUN: grep 'define x86_fp80 @f5()' %t &&
+// RUN: grep 'define void @f6(i8 signext %a0, i16 signext %a1, i32 %a2, i64 %a3, i8\* %a4)' %t &&
+// RUN: grep 'define void @f7(i32 %a0)' %t &&
+// RUN: grep 'define i64 @f8_1()' %t && 
+// RUN: grep 'define void @f8_2(i32 %a0.0, i32 %a0.1)' %t &&
+// RUN: grep 'define i64 @f9_1()' %t &&
+
+// FIXME: This is wrong, but we want the coverage of the other
+// tests. This should be the same as @f8_2.
+// RUN: grep 'define void @f9_2(%.truct.s9\* byval %a0)' %t &&
+
+// RUN: true
+
+char f0(void) {
+}
+
+short f1(void) {
+}
+
+int f2(void) {
+}
+
+float f3(void) {
+}
+
+double f4(void) {
+}
+
+long double f5(void) {
+}
+
+void f6(char a0, short a1, int a2, long long a3, void *a4) {
+}
+
+typedef enum { A, B, C } E;
+
+void f7(E a0) {
+}
+
+struct s8 {
+  int a;
+  int b;
+};
+struct s8 f8_1(void) {
+}
+void f8_2(struct s8 a0) {
+}
+
+// This should be passed just as s8.
+
+// FIXME: This is currently broken, but the test case is accepting it
+// so we get coverage of the other cases.
+struct s9 {
+  int a : 17;
+  int b;
+};
+struct s9 f9_1(void) {
+}
+void f9_2(struct s9 a0) {
+}
+
-- 
2.40.0