hanchenye-llvm-project/clang/test/CodeGenCXX/static-init.cpp

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// RUN: %clang_cc1 %s -triple=x86_64-pc-linuxs -emit-llvm -o - | FileCheck %s
// CHECK: @_ZZ1hvE1i = internal global i32 0, align 4
// CHECK: @base_req = global [4 x i8] c"foo\00", align 1
// CHECK: @base_req_uchar = global [4 x i8] c"bar\00", align 1
// CHECK: @_ZZN5test31BC1EvE1u = internal global { i8, [3 x i8] } { i8 97, [3 x i8] undef }, align 4
Compute and preserve alignment more faithfully in IR-generation. Introduce an Address type to bundle a pointer value with an alignment. Introduce APIs on CGBuilderTy to work with Address values. Change core APIs on CGF/CGM to traffic in Address where appropriate. Require alignments to be non-zero. Update a ton of code to compute and propagate alignment information. As part of this, I've promoted CGBuiltin's EmitPointerWithAlignment helper function to CGF and made use of it in a number of places in the expression emitter. The end result is that we should now be significantly more correct when performing operations on objects that are locally known to be under-aligned. Since alignment is not reliably tracked in the type system, there are inherent limits to this, but at least we are no longer confused by standard operations like derived-to-base conversions and array-to-pointer decay. I've also fixed a large number of bugs where we were applying the complete-object alignment to a pointer instead of the non-virtual alignment, although most of these were hidden by the very conservative approach we took with member alignment. Also, because IRGen now reliably asserts on zero alignments, we should no longer be subject to an absurd but frustrating recurring bug where an incomplete type would report a zero alignment and then we'd naively do a alignmentAtOffset on it and emit code using an alignment equal to the largest power-of-two factor of the offset. We should also now be emitting much more aggressive alignment attributes in the presence of over-alignment. In particular, field access now uses alignmentAtOffset instead of min. Several times in this patch, I had to change the existing code-generation pattern in order to more effectively use the Address APIs. For the most part, this seems to be a strict improvement, like doing pointer arithmetic with GEPs instead of ptrtoint. That said, I've tried very hard to not change semantics, but it is likely that I've failed in a few places, for which I apologize. ABIArgInfo now always carries the assumed alignment of indirect and indirect byval arguments. In order to cut down on what was already a dauntingly large patch, I changed the code to never set align attributes in the IR on non-byval indirect arguments. That is, we still generate code which assumes that indirect arguments have the given alignment, but we don't express this information to the backend except where it's semantically required (i.e. on byvals). This is likely a minor regression for those targets that did provide this information, but it'll be trivial to add it back in a later patch. I partially punted on applying this work to CGBuiltin. Please do not add more uses of the CreateDefaultAligned{Load,Store} APIs; they will be going away eventually. llvm-svn: 246985
2015-09-08 16:05:57 +08:00
// CHECK: @_ZZ2h2vE1i = linkonce_odr global i32 0, comdat, align 4
// CHECK: @_ZGVZ2h2vE1i = linkonce_odr global i64 0, comdat, align 8{{$}}
// CHECK: @_ZZN5test1L6getvarEiE3var = internal constant [4 x i32] [i32 1, i32 0, i32 2, i32 4], align 16
// CHECK: @_ZZN5test414useStaticLocalEvE3obj = linkonce_odr global %"struct.test4::HasVTable" zeroinitializer, comdat, align 8
struct A {
A();
~A();
};
void f() {
Compute and preserve alignment more faithfully in IR-generation. Introduce an Address type to bundle a pointer value with an alignment. Introduce APIs on CGBuilderTy to work with Address values. Change core APIs on CGF/CGM to traffic in Address where appropriate. Require alignments to be non-zero. Update a ton of code to compute and propagate alignment information. As part of this, I've promoted CGBuiltin's EmitPointerWithAlignment helper function to CGF and made use of it in a number of places in the expression emitter. The end result is that we should now be significantly more correct when performing operations on objects that are locally known to be under-aligned. Since alignment is not reliably tracked in the type system, there are inherent limits to this, but at least we are no longer confused by standard operations like derived-to-base conversions and array-to-pointer decay. I've also fixed a large number of bugs where we were applying the complete-object alignment to a pointer instead of the non-virtual alignment, although most of these were hidden by the very conservative approach we took with member alignment. Also, because IRGen now reliably asserts on zero alignments, we should no longer be subject to an absurd but frustrating recurring bug where an incomplete type would report a zero alignment and then we'd naively do a alignmentAtOffset on it and emit code using an alignment equal to the largest power-of-two factor of the offset. We should also now be emitting much more aggressive alignment attributes in the presence of over-alignment. In particular, field access now uses alignmentAtOffset instead of min. Several times in this patch, I had to change the existing code-generation pattern in order to more effectively use the Address APIs. For the most part, this seems to be a strict improvement, like doing pointer arithmetic with GEPs instead of ptrtoint. That said, I've tried very hard to not change semantics, but it is likely that I've failed in a few places, for which I apologize. ABIArgInfo now always carries the assumed alignment of indirect and indirect byval arguments. In order to cut down on what was already a dauntingly large patch, I changed the code to never set align attributes in the IR on non-byval indirect arguments. That is, we still generate code which assumes that indirect arguments have the given alignment, but we don't express this information to the backend except where it's semantically required (i.e. on byvals). This is likely a minor regression for those targets that did provide this information, but it'll be trivial to add it back in a later patch. I partially punted on applying this work to CGBuiltin. Please do not add more uses of the CreateDefaultAligned{Load,Store} APIs; they will be going away eventually. llvm-svn: 246985
2015-09-08 16:05:57 +08:00
// CHECK: load atomic i8, i8* bitcast (i64* @_ZGVZ1fvE1a to i8*) acquire, align 8
// CHECK: call i32 @__cxa_guard_acquire
// CHECK: call void @_ZN1AC1Ev
// CHECK: call i32 @__cxa_atexit(void (i8*)* bitcast (void (%struct.A*)* @_ZN1AD1Ev to void (i8*)*), i8* getelementptr inbounds (%struct.A, %struct.A* @_ZZ1fvE1a, i32 0, i32 0), i8* @__dso_handle)
// CHECK: call void @__cxa_guard_release
static A a;
}
void g() {
// CHECK: call i8* @_Znwm(i64 1)
// CHECK: call void @_ZN1AC1Ev(
static A& a = *new A;
}
int a();
void h() {
static const int i = a();
}
// CHECK: define linkonce_odr void @_Z2h2v() {{.*}} comdat {
inline void h2() {
static int i = a();
}
void h3() {
h2();
}
// PR6980: this shouldn't crash
namespace test0 {
struct A { A(); };
__attribute__((noreturn)) int throw_exception();
void test() {
throw_exception();
static A r;
}
}
namespace test1 {
// CHECK-LABEL: define internal i32 @_ZN5test1L6getvarEi(
static inline int getvar(int index) {
static const int var[] = { 1, 0, 2, 4 };
return var[index];
}
void test() { (void) getvar(2); }
}
// Make sure we emit the initializer correctly for the following:
char base_req[] = { "foo" };
unsigned char base_req_uchar[] = { "bar" };
namespace union_static_local {
// CHECK-LABEL: define internal void @_ZZN18union_static_local4testEvEN1c4mainEv
// CHECK: call void @_ZN18union_static_local1fEPNS_1xE(%"union.union_static_local::x"* bitcast ({ [2 x i8*] }* @_ZZN18union_static_local4testEvE3foo to %"union.union_static_local::x"*))
union x { long double y; const char *x[2]; };
void f(union x*);
void test() {
static union x foo = { .x = { "a", "b" } };
struct c {
static void main() {
f(&foo);
}
};
c::main();
}
}
// rdar://problem/11091093
// Static variables should be consistent across constructor
// or destructor variants.
namespace test2 {
struct A {
A();
~A();
};
struct B : virtual A {
B();
~B();
};
// If we ever implement this as a delegate ctor call, just change
// this to take variadic arguments or something.
extern int foo();
B::B() {
static int x = foo();
}
// CHECK-LABEL: define void @_ZN5test21BC2Ev
// CHECK: load atomic i8, i8* bitcast (i64* @_ZGVZN5test21BC1EvE1x to i8*) acquire,
// CHECK: call i32 @__cxa_guard_acquire(i64* @_ZGVZN5test21BC1EvE1x)
// CHECK: [[T0:%.*]] = call i32 @_ZN5test23fooEv()
// CHECK: store i32 [[T0]], i32* @_ZZN5test21BC1EvE1x,
// CHECK: call void @__cxa_guard_release(i64* @_ZGVZN5test21BC1EvE1x)
// CHECK-LABEL: define void @_ZN5test21BC1Ev
// CHECK: load atomic i8, i8* bitcast (i64* @_ZGVZN5test21BC1EvE1x to i8*) acquire,
// CHECK: call i32 @__cxa_guard_acquire(i64* @_ZGVZN5test21BC1EvE1x)
// CHECK: [[T0:%.*]] = call i32 @_ZN5test23fooEv()
// CHECK: store i32 [[T0]], i32* @_ZZN5test21BC1EvE1x,
// CHECK: call void @__cxa_guard_release(i64* @_ZGVZN5test21BC1EvE1x)
// This is just for completeness, because we actually emit this
// using a delegate dtor call.
B::~B() {
static int y = foo();
}
// CHECK-LABEL: define void @_ZN5test21BD2Ev(
// CHECK: load atomic i8, i8* bitcast (i64* @_ZGVZN5test21BD1EvE1y to i8*) acquire,
// CHECK: call i32 @__cxa_guard_acquire(i64* @_ZGVZN5test21BD1EvE1y)
// CHECK: [[T0:%.*]] = call i32 @_ZN5test23fooEv()
// CHECK: store i32 [[T0]], i32* @_ZZN5test21BD1EvE1y,
// CHECK: call void @__cxa_guard_release(i64* @_ZGVZN5test21BD1EvE1y)
// CHECK-LABEL: define void @_ZN5test21BD1Ev(
// CHECK: call void @_ZN5test21BD2Ev(
}
// This shouldn't error out.
namespace test3 {
struct A {
A();
~A();
};
struct B : virtual A {
B();
~B();
};
B::B() {
union U { char x; int i; };
static U u = { 'a' };
}
// CHECK-LABEL: define void @_ZN5test31BC2Ev(
// CHECK-LABEL: define void @_ZN5test31BC1Ev(
}
// We forgot to set the comdat when replacing the global with a different type.
namespace test4 {
struct HasVTable {
virtual void f();
};
inline HasVTable &useStaticLocal() {
static HasVTable obj;
return obj;
}
void useit() {
useStaticLocal();
}
// CHECK: define linkonce_odr dereferenceable(8) %"struct.test4::HasVTable"* @_ZN5test414useStaticLocalEv()
// CHECK: ret %"struct.test4::HasVTable"* @_ZZN5test414useStaticLocalEvE3obj
}