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Weaken an assertion in memcpyization to account for 

unnamed bitfields.

Unnamed bitfields won't have an explicit copy operation
in the AST, which breaks the strong form of the invariant.

rdar://13816940

llvm-svn: 181289
This commit is contained in:
John McCall 2013-05-07 05:20:46 +00:00
parent 790ede43de
commit 6054d5aa7b
2 changed files with 47 additions and 2 deletions
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8
clang/lib/CodeGen/CGClass.cpp
View File

@ -859,8 +859,12 @@ namespace {
}
void addNextField(FieldDecl *F) {
assert(F->getFieldIndex() == LastAddedFieldIndex + 1 &&
"Cannot aggregate non-contiguous fields.");
// For the most part, the following invariant will hold:
// F->getFieldIndex() == LastAddedFieldIndex + 1
// The one exception is that Sema won't add a copy-initializer for an
// unnamed bitfield, which will show up here as a gap in the sequence.
assert(F->getFieldIndex() >= LastAddedFieldIndex + 1 &&
"Cannot aggregate fields out of order.");
LastAddedFieldIndex = F->getFieldIndex();
// The 'first' and 'last' fields are chosen by offset, rather than field

41
clang/test/CodeGenCXX/copy-constructor-synthesis.cpp
View File

@ -136,6 +136,32 @@ void f(B b1) {
B b2 = b1;
}
// CHECK: define linkonce_odr [[A:%.*]]* @_ZN12rdar138169401AaSERKS0_(
// CHECK: [[THIS:%.*]] = load [[A]]**
// CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds [[A]]* [[THIS]], i32 0, i32 1
// CHECK-NEXT: [[T1:%.*]] = bitcast [2 x i8]* [[T0]] to i16*
// CHECK-NEXT: [[OTHER:%.*]] = load [[A]]**
// CHECK-NEXT: [[T2:%.*]] = getelementptr inbounds [[A]]* [[OTHER]], i32 0, i32 1
// CHECK-NEXT: [[T3:%.*]] = bitcast [2 x i8]* [[T2]] to i16*
// CHECK-NEXT: [[T4:%.*]] = bitcast i16* [[T1]] to i8*
// CHECK-NEXT: [[T5:%.*]] = bitcast i16* [[T3]] to i8*
// CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i64(i8* [[T4]], i8* [[T5]], i64 8, i32 8, i1 false)
// CHECK-NEXT: ret [[A]]* [[THIS]]
// CHECK: define linkonce_odr void @_ZN12rdar138169401AC2ERKS0_(
// CHECK: [[THIS:%.*]] = load [[A]]**
// CHECK-NEXT: [[T0:%.*]] = bitcast [[A]]* [[THIS]] to i8***
// CHECK-NEXT: store i8** getelementptr inbounds ([4 x i8*]* @_ZTVN12rdar138169401AE, i64 0, i64 2), i8*** [[T0]]
// CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds [[A]]* [[THIS]], i32 0, i32 1
// CHECK-NEXT: [[T1:%.*]] = bitcast [2 x i8]* [[T0]] to i16*
// CHECK-NEXT: [[OTHER:%.*]] = load [[A]]**
// CHECK-NEXT: [[T2:%.*]] = getelementptr inbounds [[A]]* [[OTHER]], i32 0, i32 1
// CHECK-NEXT: [[T3:%.*]] = bitcast [2 x i8]* [[T2]] to i16*
// CHECK-NEXT: [[T4:%.*]] = bitcast i16* [[T1]] to i8*
// CHECK-NEXT: [[T5:%.*]] = bitcast i16* [[T3]] to i8*
// CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i64(i8* [[T4]], i8* [[T5]], i64 8, i32 8, i1 false)
// CHECK-NEXT: ret void
// CHECK: define linkonce_odr void @_ZN6PR66281BC2ERKS0_(%"struct.PR6628::B"* %this, %"struct.PR6628::B"*) unnamed_addr
// CHECK: call void @_ZN6PR66281TC1Ev
// CHECK: call void @_ZN6PR66281TC1Ev
@ -154,3 +180,18 @@ void f(B b1) {
// CHECK: call void @_ZN6PR66281TD1Ev
}
// rdar://13816940
// Test above because things get weirdly re-ordered.
namespace rdar13816940 {
struct A {
virtual ~A();
unsigned short a : 1;
unsigned short : 15;
unsigned other;
};
void test(A &a) {
A x = a; // force copy constructor into existence
x = a; // also force the copy assignment operator
}
}