From 9c84d4a8a0ab6d12dca3cc15120114fedb7219bf Mon Sep 17 00:00:00 2001
From: Daniel Dunbar <daniel@zuster.org>
Date: Thu, 27 May 2010 18:42:17 +0000
Subject: [PATCH] Parse/Sema: Add support for '#pragma options align=packed',
 which, it should be noted, is not the same as __attribute__((packed)). That
 would be ridiculous!

llvm-svn: 104865
---
 clang/include/clang/Parse/Action.h    |  1 +
 clang/lib/Parse/ParsePragma.cpp       |  2 ++
 clang/lib/Sema/SemaAttr.cpp           |  7 +++++++
 clang/test/Sema/pragma-align-packed.c | 23 +++++++++++++++++++++++
 4 files changed, 33 insertions(+)
 create mode 100644 clang/test/Sema/pragma-align-packed.c

diff --git a/clang/include/clang/Parse/Action.h b/clang/include/clang/Parse/Action.h
index d0968599c8c2..122fe850a1c5 100644
--- a/clang/include/clang/Parse/Action.h
+++ b/clang/include/clang/Parse/Action.h
@@ -2567,6 +2567,7 @@ public:
   enum PragmaOptionsAlignKind {
     POAK_Native,  // #pragma options align=native
     POAK_Natural, // #pragma options align=natural
+    POAK_Packed,  // #pragma options align=packed
     POAK_Power,   // #pragma options align=power
     POAK_Mac68k,  // #pragma options align=mac68k
     POAK_Reset    // #pragma options align=reset
diff --git a/clang/lib/Parse/ParsePragma.cpp b/clang/lib/Parse/ParsePragma.cpp
index 397d816c76e4..b27e655ff429 100644
--- a/clang/lib/Parse/ParsePragma.cpp
+++ b/clang/lib/Parse/ParsePragma.cpp
@@ -140,6 +140,8 @@ void PragmaOptionsHandler::HandlePragma(Preprocessor &PP, Token &OptionsTok) {
     Kind = Action::POAK_Native;
   else if (II->isStr("natural"))
     Kind = Action::POAK_Natural;
+  else if (II->isStr("packed"))
+    Kind = Action::POAK_Packed;
   else if (II->isStr("power"))
     Kind = Action::POAK_Power;
   else if (II->isStr("mac68k"))
diff --git a/clang/lib/Sema/SemaAttr.cpp b/clang/lib/Sema/SemaAttr.cpp
index c540af2498d5..fcf5bfd66933 100644
--- a/clang/lib/Sema/SemaAttr.cpp
+++ b/clang/lib/Sema/SemaAttr.cpp
@@ -146,6 +146,13 @@ void Sema::ActOnPragmaOptionsAlign(PragmaOptionsAlignKind Kind,
     Context->setAlignment(0);
     break;
 
+    // Note that '#pragma options align=packed' is not equivalent to attribute
+    // packed, it has a different precedence relative to attribute aligned.
+  case POAK_Packed:
+    Context->push(0);
+    Context->setAlignment(1);
+    break;
+
   case POAK_Mac68k:
     // Check if the target supports this.
     if (!PP.getTargetInfo().hasAlignMac68kSupport()) {
diff --git a/clang/test/Sema/pragma-align-packed.c b/clang/test/Sema/pragma-align-packed.c
new file mode 100644
index 000000000000..6c9b06c6d6fa
--- /dev/null
+++ b/clang/test/Sema/pragma-align-packed.c
@@ -0,0 +1,23 @@
+// RUN: %clang-cc1 -triple i386-apple-darwin9 -fsyntax-only -verify %s
+
+#pragma pack(push, 1)
+struct s0 {
+  char f0;
+  int  f1 __attribute__((aligned(4)));
+};
+extern int a[sizeof(struct s0) == 5 ? 1 : -1];
+#pragma pack(pop)
+
+struct __attribute__((packed)) s1 {
+  char f0;
+  int  f1 __attribute__((aligned(4)));
+};
+extern int a[sizeof(struct s1) == 8 ? 1 : -1];
+
+#pragma options align=packed
+struct s2 {
+  char f0;
+  int  f1 __attribute__((aligned(4)));
+};
+extern int a[sizeof(struct s2) == 5 ? 1 : -1];
+#pragma options align=reset