[cfe-commits] r136991 - in /cfe/trunk: lib/AST/RecordLayoutBuilder.cpp test/CodeGen/arm-apcs-zerolength-bitfield.c
Chad Rosier
mcrosier at apple.com
Fri Aug 5 15:38:04 PDT 2011
Author: mcrosier
Date: Fri Aug 5 17:38:04 2011
New Revision: 136991
URL: http://llvm.org/viewvc/llvm-project?rev=136991&view=rev
Log:
Add support for using anonymous bitfields (e.g., int : 0) to enforce alignment.
This fixes cases where the anonymous bitfield is followed by a bitfield member.
E.g.,
struct t4
{
char foo;
long : 0;
char bar : 1;
};
rdar://9859156
Modified:
cfe/trunk/lib/AST/RecordLayoutBuilder.cpp
cfe/trunk/test/CodeGen/arm-apcs-zerolength-bitfield.c
Modified: cfe/trunk/lib/AST/RecordLayoutBuilder.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/RecordLayoutBuilder.cpp?rev=136991&r1=136990&r2=136991&view=diff
==============================================================================
--- cfe/trunk/lib/AST/RecordLayoutBuilder.cpp (original)
+++ cfe/trunk/lib/AST/RecordLayoutBuilder.cpp Fri Aug 5 17:38:04 2011
@@ -1348,12 +1348,12 @@
}
LastFD = FD;
}
- else if (Context.Target.useZeroLengthBitfieldAlignment() &&
- !Context.Target.useBitFieldTypeAlignment()) {
+ else if (!Context.Target.useBitFieldTypeAlignment() &&
+ Context.Target.useZeroLengthBitfieldAlignment()) {
FieldDecl *FD = (*Field);
- if (Context.ZeroBitfieldFollowsBitfield(FD, LastFD))
+ if (FD->isBitField() &&
+ FD->getBitWidth()->EvaluateAsInt(Context).getZExtValue() == 0)
ZeroLengthBitfield = FD;
- LastFD = FD;
}
LayoutField(*Field);
}
@@ -1411,8 +1411,8 @@
setDataSize(std::max(getDataSizeInBits(), FieldSize));
FieldOffset = 0;
} else {
- // The bitfield is allocated starting at the next offset aligned appropriately
- // for T', with length n bits.
+ // The bitfield is allocated starting at the next offset aligned
+ // appropriately for T', with length n bits.
FieldOffset = llvm::RoundUpToAlignment(getDataSizeInBits(),
Context.toBits(TypeAlign));
@@ -1451,19 +1451,30 @@
FieldAlign = TypeSize;
if (ZeroLengthBitfield) {
- // If a zero-length bitfield is inserted after a bitfield,
- // and the alignment of the zero-length bitfield is
- // greater than the member that follows it, `bar', `bar'
- // will be aligned as the type of the zero-length bitfield.
- if (ZeroLengthBitfield != D) {
- std::pair<uint64_t, unsigned> FieldInfo =
- Context.getTypeInfo(ZeroLengthBitfield->getType());
- unsigned ZeroLengthBitfieldAlignment = FieldInfo.second;
- // Ignore alignment of subsequent zero-length bitfields.
- if ((ZeroLengthBitfieldAlignment > FieldAlign) || (FieldSize == 0))
- FieldAlign = ZeroLengthBitfieldAlignment;
- if (FieldSize)
- ZeroLengthBitfield = 0;
+ std::pair<uint64_t, unsigned> FieldInfo;
+ unsigned ZeroLengthBitfieldAlignment;
+ if (IsMsStruct) {
+ // If a zero-length bitfield is inserted after a bitfield,
+ // and the alignment of the zero-length bitfield is
+ // greater than the member that follows it, `bar', `bar'
+ // will be aligned as the type of the zero-length bitfield.
+ if (ZeroLengthBitfield != D) {
+ FieldInfo = Context.getTypeInfo(ZeroLengthBitfield->getType());
+ ZeroLengthBitfieldAlignment = FieldInfo.second;
+ // Ignore alignment of subsequent zero-length bitfields.
+ if ((ZeroLengthBitfieldAlignment > FieldAlign) || (FieldSize == 0))
+ FieldAlign = ZeroLengthBitfieldAlignment;
+ if (FieldSize)
+ ZeroLengthBitfield = 0;
+ }
+ } else {
+ // The alignment of a zero-length bitfield affects the alignment
+ // of the next member. The alignment is the max of the zero
+ // length bitfield's alignment and a target specific fixed value.
+ unsigned ZeroLengthBitfieldBoundary =
+ Context.Target.getZeroLengthBitfieldBoundary();
+ if (ZeroLengthBitfieldBoundary > FieldAlign)
+ FieldAlign = ZeroLengthBitfieldBoundary;
}
}
@@ -1476,10 +1487,11 @@
// was unnecessary (-Wpacked).
unsigned UnpackedFieldAlign = FieldAlign;
uint64_t UnpackedFieldOffset = FieldOffset;
- if (!Context.Target.useBitFieldTypeAlignment())
+ if (!Context.Target.useBitFieldTypeAlignment() && !ZeroLengthBitfield)
UnpackedFieldAlign = 1;
- if (FieldPacked || !Context.Target.useBitFieldTypeAlignment())
+ if (FieldPacked ||
+ (!Context.Target.useBitFieldTypeAlignment() && !ZeroLengthBitfield))
FieldAlign = 1;
FieldAlign = std::max(FieldAlign, D->getMaxAlignment());
UnpackedFieldAlign = std::max(UnpackedFieldAlign, D->getMaxAlignment());
@@ -1500,10 +1512,14 @@
UnpackedFieldOffset = llvm::RoundUpToAlignment(UnpackedFieldOffset,
UnpackedFieldAlign);
- // Padding members don't affect overall alignment.
- if (!D->getIdentifier())
+ // Padding members don't affect overall alignment, unless zero length bitfield
+ // alignment is enabled.
+ if (!D->getIdentifier() && !Context.Target.useZeroLengthBitfieldAlignment())
FieldAlign = UnpackedFieldAlign = 1;
+ if (!IsMsStruct)
+ ZeroLengthBitfield = 0;
+
// Place this field at the current location.
FieldOffsets.push_back(FieldOffset);
Modified: cfe/trunk/test/CodeGen/arm-apcs-zerolength-bitfield.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/arm-apcs-zerolength-bitfield.c?rev=136991&r1=136990&r2=136991&view=diff
==============================================================================
--- cfe/trunk/test/CodeGen/arm-apcs-zerolength-bitfield.c (original)
+++ cfe/trunk/test/CodeGen/arm-apcs-zerolength-bitfield.c Fri Aug 5 17:38:04 2011
@@ -58,8 +58,8 @@
char bar : 1;
char bar2;
};
-static int arr6_offset[(offsetof(struct t6, bar2) == 1) ? 0 : -1];
-static int arr6_sizeof[(sizeof(struct t6) == 2) ? 0 : -1];
+static int arr6_offset[(offsetof(struct t6, bar2) == 5) ? 0 : -1];
+static int arr6_sizeof[(sizeof(struct t6) == 8) ? 0 : -1];
struct t7
{
@@ -68,8 +68,8 @@
char bar1 : 1;
char bar2;
};
-static int arr7_offset[(offsetof(struct t7, bar2) == 1) ? 0 : -1];
-static int arr7_sizeof[(sizeof(struct t7) == 2) ? 0 : -1];
+static int arr7_offset[(offsetof(struct t7, bar2) == 5) ? 0 : -1];
+static int arr7_sizeof[(sizeof(struct t7) == 8) ? 0 : -1];
struct t8
{
@@ -78,8 +78,8 @@
char bar1 : 1;
char bar2;
};
-static int arr8_offset[(offsetof(struct t8, bar2) == 1) ? 0 : -1];
-static int arr8_sizeof[(sizeof(struct t8) == 2) ? 0 : -1];
+static int arr8_offset[(offsetof(struct t8, bar2) == 5) ? 0 : -1];
+static int arr8_sizeof[(sizeof(struct t8) == 8) ? 0 : -1];
struct t9
{
@@ -88,8 +88,8 @@
char bar1 : 1;
char bar2;
};
-static int arr9_offset[(offsetof(struct t9, bar2) == 1) ? 0 : -1];
-static int arr9_sizeof[(sizeof(struct t9) == 2) ? 0 : -1];
+static int arr9_offset[(offsetof(struct t9, bar2) == 5) ? 0 : -1];
+static int arr9_sizeof[(sizeof(struct t9) == 8) ? 0 : -1];
struct t10
{
@@ -98,9 +98,8 @@
char bar1 : 1;
char bar2;
};
-static int arr10_offset[(offsetof(struct t10, bar2) == 1) ? 0 : -1];
-static int arr10_sizeof[(sizeof(struct t10) == 2) ? 0 : -1];
-
+static int arr10_offset[(offsetof(struct t10, bar2) == 5) ? 0 : -1];
+static int arr10_sizeof[(sizeof(struct t10) == 8) ? 0 : -1];
struct t11
{
@@ -110,8 +109,8 @@
char bar1 : 1;
char bar2;
};
-static int arr11_offset[(offsetof(struct t11, bar2) == 1) ? 0 : -1];
-static int arr11_sizeof[(sizeof(struct t11) == 2) ? 0 : -1];
+static int arr11_offset[(offsetof(struct t11, bar2) == 5) ? 0 : -1];
+static int arr11_sizeof[(sizeof(struct t11) == 8) ? 0 : -1];
struct t12
{
@@ -124,6 +123,117 @@
static int arr12_offset[(offsetof(struct t12, bar) == 4) ? 0 : -1];
static int arr12_sizeof[(sizeof(struct t12) == 8) ? 0 : -1];
+struct t13
+{
+ char foo;
+ long : 0;
+ char bar;
+};
+static int arr13_offset[(offsetof(struct t13, bar) == 4) ? 0 : -1];
+static int arr13_sizeof[(sizeof(struct t13) == 8) ? 0 : -1];
+
+struct t14
+{
+ char foo1;
+ int : 0;
+ char foo2 : 1;
+ short foo3 : 16;
+ char : 0;
+ short foo4 : 16;
+ char bar1;
+ int : 0;
+ char bar2;
+};
+static int arr14_bar1_offset[(offsetof(struct t14, bar1) == 10) ? 0 : -1];
+static int arr14_bar2_offset[(offsetof(struct t14, bar2) == 12) ? 0 : -1];
+static int arr14_sizeof[(sizeof(struct t14) == 16) ? 0 : -1];
+
+struct t15
+{
+ char foo;
+ char : 0;
+ int : 0;
+ char bar;
+ long : 0;
+ char : 0;
+};
+static int arr15_offset[(offsetof(struct t15, bar) == 4) ? 0 : -1];
+static int arr15_sizeof[(sizeof(struct t15) == 8) ? 0 : -1];
+
+struct t16
+{
+ long : 0;
+ char bar;
+};
+static int arr16_offset[(offsetof(struct t16, bar) == 0) ? 0 : -1];
+static int arr16_sizeof[(sizeof(struct t16) == 4) ? 0 : -1];
+
+struct t17
+{
+ char foo;
+ long : 0;
+ long : 0;
+ char : 0;
+ char bar;
+};
+static int arr17_offset[(offsetof(struct t17, bar) == 4) ? 0 : -1];
+static int arr17_sizeof[(sizeof(struct t17) == 8) ? 0 : -1];
+
+struct t18
+{
+ long : 0;
+ long : 0;
+ char : 0;
+};
+static int arr18_sizeof[(sizeof(struct t18) == 0) ? 0 : -1];
+
+struct t19
+{
+ char foo1;
+ long foo2 : 1;
+ char : 0;
+ long foo3 : 32;
+ char bar;
+};
+static int arr19_offset[(offsetof(struct t19, bar) == 8) ? 0 : -1];
+static int arr19_sizeof[(sizeof(struct t19) == 12) ? 0 : -1];
+
+struct t20
+{
+ short : 0;
+ int foo : 1;
+ long : 0;
+ char bar;
+};
+static int arr20_offset[(offsetof(struct t20, bar) == 4) ? 0 : -1];
+static int arr20_sizeof[(sizeof(struct t20) == 8) ? 0 : -1];
+
+struct t21
+{
+ short : 0;
+ int foo1 : 1;
+ char : 0;
+ int foo2 : 16;
+ long : 0;
+ char bar1;
+ int bar2;
+ long bar3;
+ char foo3 : 8;
+ char : 0;
+ long : 0;
+ int foo4 : 32;
+ short foo5: 1;
+ long bar4;
+ short foo6: 16;
+ short foo7: 16;
+ short foo8: 16;
+};
+static int arr21_bar1_offset[(offsetof(struct t21, bar1) == 8) ? 0 : -1];
+static int arr21_bar2_offset[(offsetof(struct t21, bar2) == 12) ? 0 : -1];
+static int arr21_bar3_offset[(offsetof(struct t21, bar3) == 16) ? 0 : -1];
+static int arr21_bar4_offset[(offsetof(struct t21, bar4) == 32) ? 0 : -1];
+static int arr21_sizeof[(sizeof(struct t21) == 44) ? 0 : -1];
+
int main() {
return 0;
}
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