Leonard Chan 71568a9e28 [clang] Frontend components for the relative vtables ABI (round 2)
This patch contains all of the clang changes from D72959.

- Generalize the relative vtables ABI such that it can be used by other targets.
- Add an enum VTableComponentLayout which controls whether components in the
  vtable should be pointers to other structs or relative offsets to those structs.
  Other ABIs can change this enum to restructure how components in the vtable
  are laid out/accessed.
- Add methods to ConstantInitBuilder for inserting relative offsets to a
  specified position in the aggregate being constructed.
- Fix failing tests under new PM and ASan and MSan issues.

See D72959 for background info.

Differential Revision: https://reviews.llvm.org/D77592
2020-06-11 11:17:08 -07:00

25 lines
1.6 KiB
C++

// Check the layout of the vtable for a normal class.
// The Fuchsia relative vtables ABI will be hidden behind a flag for now as part
// of a soft incremental rollout. This ABI should only be used if the flag for
// it is passed on Fuchsia.
// RUN: %clang_cc1 %s -triple=aarch64-unknown-fuchsia -S -o - -emit-llvm -fexperimental-relative-c++-abi-vtables | FileCheck --check-prefix=RELATIVE-ABI %s
// RUN: %clang_cc1 %s -triple=aarch64-unknown-fuchsia -S -o - -emit-llvm -fno-experimental-relative-c++-abi-vtables | FileCheck --check-prefix=DEFAULT-ABI %s
// RUN: %clang_cc1 %s -triple=aarch64-unknown-fuchsia -S -o - -emit-llvm | FileCheck --check-prefix=DEFAULT-ABI %s
// VTable contains offsets and references to the hidden symbols
// RELATIVE-ABI: @_ZTV1A.local = private unnamed_addr constant { [3 x i32] } { [3 x i32] [i32 0, i32 trunc (i64 sub (i64 ptrtoint ({ i8*, i8* }** @_ZTI1A.rtti_proxy to i64), i64 ptrtoint (i32* getelementptr inbounds ({ [3 x i32] }, { [3 x i32] }* @_ZTV1A.local, i32 0, i32 0, i32 2) to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (void (%class.A*)* @_ZN1A3fooEv.stub to i64), i64 ptrtoint (i32* getelementptr inbounds ({ [3 x i32] }, { [3 x i32] }* @_ZTV1A.local, i32 0, i32 0, i32 2) to i64)) to i32)] }, align 4
// RELATIVE-ABI: @_ZTV1A = unnamed_addr alias { [3 x i32] }, { [3 x i32] }* @_ZTV1A.local
// DEFAULT-ABI: @_ZTV1A = unnamed_addr constant { [3 x i8*] } { [3 x i8*] [i8* null, i8* bitcast ({ i8*, i8* }* @_ZTI1A to i8*), i8* bitcast (void (%class.A*)* @_ZN1A3fooEv to i8*)] }, align 8
class A {
public:
virtual void foo();
};
void A::foo() {}
void A_foo(A *a) {
a->foo();
}