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llvm-project/clang/test/CodeGenCXX/vtable-align.cpp

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CodeGen: Use a fixed alignment for vtables. Pointer-sized alignment is sufficient as we only ever read single values from the table. Otherwise we'd bump the alignment to 16 bytes in the backend if the vtable is larger than 16 bytes. This is great for structures that are accessed with vector instructions or copied around, but that's simply not the case for vtables. Shrinks the data segment of a Release x86_64 clang by 0.3%. The wins are larger for i386 and code bases that use vtables more often than we do. This matches the behavior of GCC 5. llvm-svn: 217495
2014-09-10 20:50:59 +08:00
// RUN: %clang_cc1 %s -triple=i386-apple-darwin10 -emit-llvm -o - | FileCheck %s -check-prefix=CHECK-32
// RUN: %clang_cc1 %s -triple=x86_64-apple-darwin10 -emit-llvm -o - | FileCheck %s -check-prefix=CHECK-64
struct A {
virtual void f();
virtual void g();
virtual void h();
};
void A::f() {}
[test] Add {{.*}} to make tests immune to dso_local/dso_preemptable/(none) differences For a definition (of most linkage types), dso_local is set for ELF -fno-pic/-fpie and COFF, but not for Mach-O. This nuance causes unneeded binary format differences. This patch replaces (function) `define ` with `define{{.*}} `, (variable/constant/alias) `= ` with `={{.*}} `, or inserts appropriate `{{.*}} ` if there is an explicit linkage. * Clang will set dso_local for Mach-O, which is currently implied by TargetMachine.cpp. This will make COFF/Mach-O and executable ELF similar. * Eventually I hope we can make dso_local the textual LLVM IR default (write explicit "dso_preemptable" when applicable) and -fpic ELF will be similar to everything else. This patch helps move toward that goal.
2020-12-31 12:45:56 +08:00
// CHECK-32: @_ZTV1A ={{.*}} unnamed_addr constant { [5 x i8*] } { [5 x i8*] [i8* null, i8* bitcast ({ i8*, i8* }* @_ZTI1A to i8*), i8* bitcast (void (%struct.A*)* @_ZN1A1fEv to i8*), i8* bitcast (void (%struct.A*)* @_ZN1A1gEv to i8*), i8* bitcast (void (%struct.A*)* @_ZN1A1hEv to i8*)] }, align 4
// CHECK-32: @_ZTS1A ={{.*}} constant [3 x i8] c"1A\00", align 1
// CHECK-32: @_ZTI1A ={{.*}} constant { i8*, i8* } { i8* bitcast (i8** getelementptr inbounds (i8*, i8** @_ZTVN10__cxxabiv117__class_type_infoE, i32 2) to i8*), i8* getelementptr inbounds ([3 x i8], [3 x i8]* @_ZTS1A, i32 0, i32 0) }, align 4
// CHECK-64: @_ZTV1A ={{.*}} unnamed_addr constant { [5 x i8*] } { [5 x i8*] [i8* null, i8* bitcast ({ i8*, i8* }* @_ZTI1A to i8*), i8* bitcast (void (%struct.A*)* @_ZN1A1fEv to i8*), i8* bitcast (void (%struct.A*)* @_ZN1A1gEv to i8*), i8* bitcast (void (%struct.A*)* @_ZN1A1hEv to i8*)] }, align 8
// CHECK-64: @_ZTS1A ={{.*}} constant [3 x i8] c"1A\00", align 1
// CHECK-64: @_ZTI1A ={{.*}} constant { i8*, i8* } { i8* bitcast (i8** getelementptr inbounds (i8*, i8** @_ZTVN10__cxxabiv117__class_type_infoE, i64 2) to i8*), i8* getelementptr inbounds ([3 x i8], [3 x i8]* @_ZTS1A, i32 0, i32 0) }, align 8