DmitryPolukhin updated this revision to Diff 41481.
DmitryPolukhin added a comment.
Added more testcases to cover combination of explicit alignment of bit-filed
with packed attribute. Also added testing on ARM for bit-filed layout test.
http://reviews.llvm.org/D14980
Files:
lib/AST/RecordLayoutBuilder.cpp
test/Sema/bitfield-layout.c
Index: test/Sema/bitfield-layout.c
===================================================================
--- test/Sema/bitfield-layout.c
+++ test/Sema/bitfield-layout.c
@@ -1,41 +1,72 @@
// RUN: %clang_cc1 %s -fsyntax-only -verify -triple=i686-apple-darwin9
+// RUN: %clang_cc1 %s -fsyntax-only -verify -triple=armv7
// expected-no-diagnostics
+#include <stddef.h>
-#define CHECK_SIZE(kind, name, size) extern int name##1[sizeof(kind name) == size ? 1 : -1];
-#define CHECK_ALIGN(kind, name, size) extern int name##2[__alignof(kind name) == size ? 1 : -1];
+#define CHECK_SIZE(kind, name, size) \
+ extern int name##1[sizeof(kind name) == size ? 1 : -1];
+#define CHECK_ALIGN(kind, name, size) \
+ extern int name##2[__alignof(kind name) == size ? 1 : -1];
+#define CHECK_OFFSET(kind, name, member, offset) \
+ extern int name##2[offsetof(kind name, member) == offset ? 1 : -1];
// Zero-width bit-fields
struct a {char x; int : 0; char y;};
+#ifdef __ARM_EABI__
+CHECK_SIZE(struct, a, 8)
+CHECK_ALIGN(struct, a, 4)
+#else
CHECK_SIZE(struct, a, 5)
CHECK_ALIGN(struct, a, 1)
+#endif
// Zero-width bit-fields with packed
struct __attribute__((packed)) a2 { short x : 9; char : 0; int y : 17; };
CHECK_SIZE(struct, a2, 5)
CHECK_ALIGN(struct, a2, 1)
// Zero-width bit-fields at the end of packed struct
struct __attribute__((packed)) a3 { short x : 9; int : 0; };
+#ifdef __ARM_EABI__
+CHECK_SIZE(struct, a3, 4)
+CHECK_ALIGN(struct, a3, 4)
+#else
CHECK_SIZE(struct, a3, 4)
CHECK_ALIGN(struct, a3, 1)
+#endif
// For comparison, non-zero-width bit-fields at the end of packed struct
struct __attribute__((packed)) a4 { short x : 9; int : 1; };
CHECK_SIZE(struct, a4, 2)
CHECK_ALIGN(struct, a4, 1)
union b {char x; int : 0; char y;};
+#ifdef __ARM_EABI__
+CHECK_SIZE(union, b, 4)
+CHECK_ALIGN(union, b, 4)
+#else
CHECK_SIZE(union, b, 1)
CHECK_ALIGN(union, b, 1)
+#endif
// Unnamed bit-field align
struct c {char x; int : 20;};
+#ifdef __ARM_EABI__
+CHECK_SIZE(struct, c, 4)
+CHECK_ALIGN(struct, c, 4)
+#else
CHECK_SIZE(struct, c, 4)
CHECK_ALIGN(struct, c, 1)
+#endif
union d {char x; int : 20;};
+#ifdef __ARM_EABI__
+CHECK_SIZE(union, d, 4)
+CHECK_ALIGN(union, d, 4)
+#else
CHECK_SIZE(union, d, 3)
CHECK_ALIGN(union, d, 1)
+#endif
// Bit-field packing
struct __attribute__((packed)) e {int x : 4, y : 30, z : 30;};
@@ -56,3 +87,99 @@
CHECK_SIZE(struct, s0, 0x32100008)
CHECK_ALIGN(struct, s0, 4)
+// Bit-field with explicit align bigger than normal.
+struct g0 {
+ char a;
+ __attribute__((aligned(16))) int b : 1;
+ char c;
+};
+
+CHECK_SIZE(struct, g0, 32);
+CHECK_ALIGN(struct, g0, 16);
+CHECK_OFFSET(struct, g0, c, 17);
+
+// Bit-field with explicit align smaller than normal.
+struct g1 {
+ char a;
+ __attribute__((aligned(2))) int b : 1;
+ char c;
+};
+
+CHECK_SIZE(struct, g1, 4);
+CHECK_ALIGN(struct, g1, 4);
+CHECK_OFFSET(struct, g1, c, 3);
+
+// Same as above but without explicit align.
+struct g2 {
+ char a;
+ int b : 1;
+ char c;
+};
+
+CHECK_SIZE(struct, g2, 4);
+CHECK_ALIGN(struct, g2, 4);
+CHECK_OFFSET(struct, g2, c, 2);
+
+// Explicit attribute align on bit-field has precedence over packed attribute
+// applied too the struct.
+struct __attribute__((packed)) g3 {
+ char a;
+ __attribute__((aligned(16))) int b : 1;
+ char c;
+};
+
+CHECK_SIZE(struct, g3, 32);
+CHECK_ALIGN(struct, g3, 16);
+CHECK_OFFSET(struct, g3, c, 17);
+
+struct __attribute__((packed)) g4 {
+ char a;
+ __attribute__((aligned(2))) int b : 1;
+ char c;
+};
+
+CHECK_SIZE(struct, g4, 4);
+CHECK_ALIGN(struct, g4, 2);
+CHECK_OFFSET(struct, g4, c, 3);
+
+struct g5 {
+ char : 1;
+ __attribute__((aligned(1))) int n : 24;
+};
+CHECK_SIZE(struct, g5, 4);
+CHECK_ALIGN(struct, g5, 4);
+
+struct __attribute__((packed)) g6 {
+ char : 1;
+ __attribute__((aligned(1))) int n : 24;
+};
+CHECK_SIZE(struct, g6, 4);
+CHECK_ALIGN(struct, g6, 1);
+
+struct g7 {
+ char : 1;
+ __attribute__((aligned(1))) int n : 25;
+};
+CHECK_SIZE(struct, g7, 8);
+CHECK_ALIGN(struct, g7, 4);
+
+struct __attribute__((packed)) g8 {
+ char : 1;
+ __attribute__((aligned(1))) int n : 25;
+};
+CHECK_SIZE(struct, g8, 5);
+CHECK_ALIGN(struct, g8, 1);
+
+struct g9 {
+ __attribute__((aligned(1))) char a : 2, b : 2, c : 2, d : 2, e : 2;
+ int i;
+};
+CHECK_SIZE(struct, g9, 12);
+CHECK_ALIGN(struct, g9, 4);
+
+struct __attribute__((packed)) g10 {
+ __attribute__((aligned(1))) char a : 2, b : 2, c : 2, d : 2, e : 2;
+ int i;
+};
+CHECK_SIZE(struct, g10, 9);
+CHECK_ALIGN(struct, g10, 1);
Index: lib/AST/RecordLayoutBuilder.cpp
===================================================================
--- lib/AST/RecordLayoutBuilder.cpp
+++ lib/AST/RecordLayoutBuilder.cpp
@@ -1552,7 +1552,8 @@
FieldAlign = 1;
// But, if there's an 'aligned' attribute on the field, honor that.
- if (unsigned ExplicitFieldAlign = D->getMaxAlignment()) {
+ unsigned ExplicitFieldAlign = D->getMaxAlignment();
+ if (ExplicitFieldAlign) {
FieldAlign = std::max(FieldAlign, ExplicitFieldAlign);
UnpackedFieldAlign = std::max(UnpackedFieldAlign, ExplicitFieldAlign);
}
@@ -1601,10 +1602,12 @@
(AllowPadding &&
(FieldOffset & (FieldAlign-1)) + FieldSize > TypeSize)) {
FieldOffset = llvm::RoundUpToAlignment(FieldOffset, FieldAlign);
- }
+ } else if (ExplicitFieldAlign)
+ FieldOffset = llvm::RoundUpToAlignment(FieldOffset, ExplicitFieldAlign);
// Repeat the computation for diagnostic purposes.
if (FieldSize == 0 ||
+ ExplicitFieldAlign ||
(AllowPadding &&
(UnpackedFieldOffset & (UnpackedFieldAlign-1)) + FieldSize > TypeSize))
UnpackedFieldOffset = llvm::RoundUpToAlignment(UnpackedFieldOffset,
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