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Compute interface instanceStart and instanceSize using the record 

layout.
 - This is much simpler / more efficient.

 - This also properly computes the size in the presence of bit-fields.

llvm-svn: 70916
This commit is contained in:
Daniel Dunbar 2009-05-04 21:26:30 +00:00
parent a8aa586a72
commit 9252ee1779
2 changed files with 29 additions and 25 deletions
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29
clang/lib/CodeGen/CGObjCMac.cpp
View File

@ -4219,35 +4219,16 @@ llvm::GlobalVariable * CGObjCNonFragileABIMac::BuildClassMetaData(
void CGObjCNonFragileABIMac::GetClassSizeInfo(const ObjCImplementationDecl *OID,
uint32_t &InstanceStart,
uint32_t &InstanceSize) {
// Find first and last (non-padding) ivars in this interface.
const ASTRecordLayout &RL =
CGM.getContext().getASTObjCImplementationLayout(OID);
// FIXME: Use iterator.
llvm::SmallVector<ObjCIvarDecl*, 16> OIvars;
GetNamedIvarList(OID->getClassInterface(), OIvars);
if (OIvars.empty()) {
if (!RL.getFieldCount()) {
InstanceStart = InstanceSize = 0;
return;
}
const ObjCIvarDecl *First = OIvars.front();
const ObjCIvarDecl *Last = OIvars.back();
InstanceStart = ComputeIvarBaseOffset(CGM, OID, First);
const llvm::Type *FieldTy =
CGM.getTypes().ConvertTypeForMem(Last->getType());
unsigned Size = CGM.getTargetData().getTypePaddedSize(FieldTy);
// FIXME. This breaks compatibility with llvm-gcc-4.2 (but makes it compatible
// with gcc-4.2). We postpone this for now.
#if 0
if (Last->isBitField()) {
Expr *BitWidth = Last->getBitWidth();
uint64_t BitFieldSize =
BitWidth->EvaluateAsInt(CGM.getContext()).getZExtValue();
Size = (BitFieldSize / 8) + ((BitFieldSize % 8) != 0);
}
#endif
InstanceSize = ComputeIvarBaseOffset(CGM, OID, Last) + Size;
InstanceStart = RL.getFieldOffset(0) / 8;
InstanceSize = llvm::RoundUpToAlignment(RL.getNextOffset(), 8) / 8;
}
void CGObjCNonFragileABIMac::GenerateClass(const ObjCImplementationDecl *ID) {

23
clang/test/CodeGenObjC/interface-layout-64.m
View File

@ -7,6 +7,8 @@
// RUN: grep '@"OBJC_IVAR_$_I5._iv5" = global i64 24, section "__DATA, __objc_const", align 8' %t &&
// RUN: grep '@"OBJC_IVAR_$_I5._iv6_synth" = global i64 28, section "__DATA, __objc_const", align 8' %t &&
// RUN: grep '@"OBJC_IVAR_$_I5._iv7_synth" = global i64 32, section "__DATA, __objc_const", align 8' %t &&
// RUN: grep '_OBJC_CLASS_RO_$_I6" = internal global .* { i32 2, i32 0, i32 1, .*' %t &&
// RUN: grep '_OBJC_CLASS_RO_$_I8" = internal global .* { i32 0, i32 8, i32 16, .*' %t &&
// RUN: true
@ -54,3 +56,24 @@ struct s0 {
@synthesize prop1 = _iv7_synth;
@synthesize prop2 = _iv5;
@end
// The size rounds up to the next available byte.
@interface I6 {
unsigned iv0 : 2;
}
@end
@implementation I6
@end
// The start of the subclass includes padding for its own alignment.
@interface I7 {
char a;
}
@end
@interface I8 : I7 {
double b;
}
@end
@implementation I8
@end