r261321 - pr26544: Bitfield layout with pragma pack and attributes "packed" and
Alexey Bataev via cfe-commits
cfe-commits at lists.llvm.org
Fri Feb 19 03:23:28 PST 2016
Author: abataev
Date: Fri Feb 19 05:23:28 2016
New Revision: 261321
URL: http://llvm.org/viewvc/llvm-project?rev=261321&view=rev
Log:
pr26544: Bitfield layout with pragma pack and attributes "packed" and
"aligned", by Vladimir Yakovlev
Fix clang/gcc incompatibility of bitfields layout in the presence of
pragma packed and attributes aligned and packed.
Differential Revision: http://reviews.llvm.org/D17023
Added:
cfe/trunk/test/Sema/bitfield-layout_1.c
Modified:
cfe/trunk/lib/AST/RecordLayoutBuilder.cpp
Modified: cfe/trunk/lib/AST/RecordLayoutBuilder.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/RecordLayoutBuilder.cpp?rev=261321&r1=261320&r2=261321&view=diff
==============================================================================
--- cfe/trunk/lib/AST/RecordLayoutBuilder.cpp (original)
+++ cfe/trunk/lib/AST/RecordLayoutBuilder.cpp Fri Feb 19 05:23:28 2016
@@ -1558,10 +1558,13 @@ void ItaniumRecordLayoutBuilder::LayoutB
// But, if there's a #pragma pack in play, that takes precedent over
// even the 'aligned' attribute, for non-zero-width bitfields.
+ unsigned MaxFieldAlignmentInBits = Context.toBits(MaxFieldAlignment);
if (!MaxFieldAlignment.isZero() && FieldSize) {
- unsigned MaxFieldAlignmentInBits = Context.toBits(MaxFieldAlignment);
- FieldAlign = std::min(FieldAlign, MaxFieldAlignmentInBits);
UnpackedFieldAlign = std::min(UnpackedFieldAlign, MaxFieldAlignmentInBits);
+ if (FieldPacked)
+ FieldAlign = UnpackedFieldAlign;
+ else
+ FieldAlign = std::min(FieldAlign, MaxFieldAlignmentInBits);
}
// But, ms_struct just ignores all of that in unions, even explicit
@@ -1601,6 +1604,8 @@ void ItaniumRecordLayoutBuilder::LayoutB
(FieldOffset & (FieldAlign-1)) + FieldSize > TypeSize)) {
FieldOffset = llvm::alignTo(FieldOffset, FieldAlign);
} else if (ExplicitFieldAlign &&
+ (MaxFieldAlignmentInBits == 0 ||
+ ExplicitFieldAlign <= MaxFieldAlignmentInBits) &&
Context.getTargetInfo().useExplicitBitFieldAlignment()) {
// TODO: figure it out what needs to be done on targets that don't honor
// bit-field type alignment like ARM APCS ABI.
@@ -1614,6 +1619,8 @@ void ItaniumRecordLayoutBuilder::LayoutB
UnpackedFieldOffset =
llvm::alignTo(UnpackedFieldOffset, UnpackedFieldAlign);
else if (ExplicitFieldAlign &&
+ (MaxFieldAlignmentInBits == 0 ||
+ ExplicitFieldAlign <= MaxFieldAlignmentInBits) &&
Context.getTargetInfo().useExplicitBitFieldAlignment())
UnpackedFieldOffset =
llvm::alignTo(UnpackedFieldOffset, ExplicitFieldAlign);
Added: cfe/trunk/test/Sema/bitfield-layout_1.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/bitfield-layout_1.c?rev=261321&view=auto
==============================================================================
--- cfe/trunk/test/Sema/bitfield-layout_1.c (added)
+++ cfe/trunk/test/Sema/bitfield-layout_1.c Fri Feb 19 05:23:28 2016
@@ -0,0 +1,202 @@
+// RUN: %clang_cc1 %s -fsyntax-only -verify -triple=i686-apple-darwin9
+// RUN: %clang_cc1 %s -fsyntax-only -verify -triple=arm-linux-gnueabihf
+// RUN: %clang_cc1 %s -fsyntax-only -verify -triple=aarch64-linux-gnu
+// RUN: %clang_cc1 %s -fsyntax-only -verify -triple=x86_64-pc-linux-gnu
+// expected-no-diagnostics
+
+#define CHECK_SIZE(name, size) \
+ extern int name##_1[sizeof(name) == size ? 1 : -1];
+
+
+struct __attribute__((packed)) {
+ int a;
+ int b : 4;
+ int c : 32;
+} s0;
+CHECK_SIZE(s0,9)
+
+#pragma pack (1)
+struct {
+ int a;
+ int b : 4;
+ int c : 32;
+} s1;
+CHECK_SIZE(s1,9)
+
+#pragma pack (2)
+struct {
+ int a;
+ int b : 4;
+ int c : 32;
+} s2;
+CHECK_SIZE(s2,10)
+
+#pragma pack (2)
+struct __attribute__((packed)) {
+ int a;
+ int b : 4;
+ int c : 32;
+} s3;
+CHECK_SIZE(s3,10)
+
+#pragma pack (4)
+struct __attribute__((packed)) {
+ int a;
+ int b : 4;
+ int c : 32;
+} s4;
+CHECK_SIZE(s4,12)
+
+#pragma pack (16)
+struct {
+ int a;
+ int __attribute__((packed)) b : 4;
+ int __attribute__((packed)) c : 32;
+} s41;
+CHECK_SIZE(s41,12)
+
+#pragma pack (16)
+struct {
+ int a;
+ int b : 4;
+ int c : 32;
+} s5;
+CHECK_SIZE(s5,12)
+
+#pragma pack (1)
+struct __attribute__((aligned(4))) {
+ int a;
+ int b : 4;
+ int c : 32;
+} s6;
+CHECK_SIZE(s6,12)
+
+#pragma pack (2)
+struct {
+ char a;
+ int b : 4;
+ int c : 32;
+ char s;
+} s7;
+CHECK_SIZE(s7,8)
+
+#pragma pack (1)
+struct {
+ char a;
+ int b : 4;
+ int c : 28;
+ char s;
+} s8;
+CHECK_SIZE(s8,6)
+
+#pragma pack (8)
+struct {
+ char a;
+ int b : 4;
+ int c : 28;
+ char s;
+} s9;
+CHECK_SIZE(s9,8)
+
+#pragma pack (8)
+struct {
+ char a;
+ char s;
+} s10;
+CHECK_SIZE(s10,2)
+
+#pragma pack(4)
+struct {
+ char a;
+ int b : 4;
+ int c : 28;
+ char s1;
+ char s2;
+ char s3;
+} s11;
+CHECK_SIZE(s11,8)
+
+#pragma pack(4)
+struct {
+ short s1;
+ int a1 : 17;
+ int a2 : 17;
+ int a3 : 30;
+ short s2;
+} s12;
+CHECK_SIZE(s12,12)
+
+#pragma pack(4)
+struct {
+ char c1;
+ int i1 : 17;
+ int i2 : 17;
+ int i3 : 30;
+ char c2;
+} s13;
+CHECK_SIZE(s13,12)
+
+#pragma pack(2)
+struct {
+ char a;
+ int s;
+} s14;
+CHECK_SIZE(s14,6)
+
+#pragma pack(4)
+struct {
+ char a;
+ short s;
+} s15;
+CHECK_SIZE(s15,4)
+
+#pragma pack(2)
+struct {
+ char a;
+ int b : 4;
+ int c : 28;
+ char s1;
+ char s2;
+ char s3;
+} s16;
+CHECK_SIZE(s16,8)
+
+#pragma pack (16)
+struct {
+ int __attribute__((packed)) a;
+ int __attribute__((packed)) b : 4;
+ int __attribute__((packed)) c : 32;
+} s17;
+CHECK_SIZE(s17,12)
+
+#pragma pack (16)
+struct {
+ int __attribute__((aligned(8))) a;
+ int __attribute__((aligned(8))) b : 4;
+ int __attribute__((aligned(8))) c : 32;
+} s18;
+CHECK_SIZE(s18,24)
+
+#pragma pack (16)
+struct {
+ int __attribute__((aligned(1))) a;
+ int __attribute__((aligned(1))) b : 4;
+ int __attribute__((aligned(1))) c : 32;
+} s19;
+CHECK_SIZE(s19,12)
+
+#pragma pack (1)
+struct __attribute__((aligned(8))) {
+ int a;
+ int b : 4;
+ int c : 32;
+} s20;
+CHECK_SIZE(s20,16)
+
+#pragma pack (2)
+struct {
+ int __attribute__((aligned(8))) a;
+ int __attribute__((aligned(8))) b : 4;
+ int __attribute__((aligned(8))) c : 32;
+} s21;
+CHECK_SIZE(s21,10)
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