28cb620321
An global value in the `llvm.used` list does not have GC root semantics on ELF targets. This will be changed in a subsequent backend patch. Change some `llvm.used` in the ELF code path to use `llvm.compiler.used` to prevent undesired GC root semantics. Change one extern "C" alias (due to `__attribute__((used))` in extern "C") to use `llvm.compiler.used` on all targets. GNU ld has a rule "`__start_/__stop_` references from a live input section retain the associated C identifier name sections", which LLD may drop entirely (currently refined to exclude SHF_LINK_ORDER/SHF_GROUP) in a future release (the rule makes it clumsy to GC metadata sections; D96914 added a way to try the potential future behavior). For `llvm.used` global values defined in a C identifier name section, keep using `llvm.used` so that the future LLD change will not affect them. rnk kindly categorized the changes: ``` ObjC/blocks: this wants GC root semantics, since ObjC mainly runs on Mac. MS C++ ABI stuff: wants GC root semantics, no change OpenMP: unsure, but GC root semantics probably don't hurt CodeGenModule: affected in this patch to *not* use GC root semantics so that __attribute__((used)) behavior remains the same on ELF, plus two other minor use cases that don't want GC semantics Coverage: Probably want GC root semantics CGExpr.cpp: refers to LTO, wants GC root CGDeclCXX.cpp: one is MS ABI specific, so yes GC root, one is some other C++ init functionality, which should form GC roots (C++ initializers can have side effects and must run) CGDecl.cpp: Changed in this patch for __attribute__((used)) ``` Differential Revision: https://reviews.llvm.org/D97446
36 lines
2.9 KiB
C++
36 lines
2.9 KiB
C++
// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu %s -emit-llvm -o - | FileCheck %s --check-prefix=X86_64_LINUX
|
|
// RUN: %clang_cc1 -triple i386-unknown-linux-gnu %s -emit-llvm -o - | FileCheck %s --check-prefix=X86_LINUX
|
|
// RUN: %clang_cc1 -triple x86_64-pc-win32 %s -emit-llvm -o - | FileCheck %s --check-prefix=X86_64_WIN
|
|
// RUN: %clang_cc1 -triple i386-pc-win32 %s -emit-llvm -o - | FileCheck %s --check-prefix=X86_WIN
|
|
// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnux32 %s -emit-llvm -o - | FileCheck %s --check-prefix=X86_64_LINUX
|
|
|
|
#ifdef __x86_64__
|
|
typedef __UINT64_TYPE__ uword;
|
|
#else
|
|
typedef __UINT32_TYPE__ uword;
|
|
#endif
|
|
|
|
__attribute__((interrupt)) void foo7(int *a, uword b) {}
|
|
namespace S {
|
|
__attribute__((interrupt)) void foo8(int *a) {}
|
|
}
|
|
struct St {
|
|
static void foo9(int *a) __attribute__((interrupt)) {}
|
|
};
|
|
// X86_64_LINUX: @llvm.compiler.used = appending global [3 x i8*] [i8* bitcast (void (i32*, i64)* @{{.*}}foo7{{.*}} to i8*), i8* bitcast (void (i32*)* @{{.*}}foo8{{.*}} to i8*), i8* bitcast (void (i32*)* @{{.*}}foo9{{.*}} to i8*)], section "llvm.metadata"
|
|
// X86_64_LINUX: define{{.*}} x86_intrcc void @{{.*}}foo7{{.*}}(i32* byval(i32) %{{.+}}, i64 %{{.+}})
|
|
// X86_64_LINUX: define{{.*}} x86_intrcc void @{{.*}}foo8{{.*}}(i32* byval(i32) %{{.+}})
|
|
// X86_64_LINUX: define linkonce_odr x86_intrcc void @{{.*}}foo9{{.*}}(i32* byval(i32) %{{.+}})
|
|
// X86_LINUX: @llvm.compiler.used = appending global [3 x i8*] [i8* bitcast (void (i32*, i32)* @{{.*}}foo7{{.*}} to i8*), i8* bitcast (void (i32*)* @{{.*}}foo8{{.*}} to i8*), i8* bitcast (void (i32*)* @{{.*}}foo9{{.*}} to i8*)], section "llvm.metadata"
|
|
// X86_LINUX: define{{.*}} x86_intrcc void @{{.*}}foo7{{.*}}(i32* byval(i32) %{{.+}}, i32 %{{.+}})
|
|
// X86_LINUX: define{{.*}} x86_intrcc void @{{.*}}foo8{{.*}}(i32* byval(i32) %{{.+}})
|
|
// X86_LINUX: define linkonce_odr x86_intrcc void @{{.*}}foo9{{.*}}(i32* byval(i32) %{{.+}})
|
|
// X86_64_WIN: @llvm.used = appending global [3 x i8*] [i8* bitcast (void (i32*, i64)* @{{.*}}foo7{{.*}} to i8*), i8* bitcast (void (i32*)* @{{.*}}foo8{{.*}} to i8*), i8* bitcast (void (i32*)* @{{.*}}foo9{{.*}} to i8*)], section "llvm.metadata"
|
|
// X86_64_WIN: define dso_local x86_intrcc void @{{.*}}foo7{{.*}}(i32* byval(i32) %{{.+}}, i64 %{{.+}})
|
|
// X86_64_WIN: define dso_local x86_intrcc void @{{.*}}foo8{{.*}}(i32* byval(i32) %{{.+}})
|
|
// X86_64_WIN: define linkonce_odr dso_local x86_intrcc void @{{.*}}foo9{{.*}}(i32* byval(i32) %{{.+}})
|
|
// X86_WIN: @llvm.used = appending global [3 x i8*] [i8* bitcast (void (i32*, i32)* @{{.*}}foo7{{.*}} to i8*), i8* bitcast (void (i32*)* @{{.*}}foo8{{.*}} to i8*), i8* bitcast (void (i32*)* @{{.*}}foo9{{.*}} to i8*)], section "llvm.metadata"
|
|
// X86_WIN: define dso_local x86_intrcc void @{{.*}}foo7{{.*}}(i32* byval(i32) %{{.+}}, i32 %{{.+}})
|
|
// X86_WIN: define dso_local x86_intrcc void @{{.*}}foo8{{.*}}(i32* byval(i32) %{{.+}})
|
|
// X86_WIN: define linkonce_odr dso_local x86_intrcc void @{{.*}}foo9{{.*}}(i32* byval(i32) %{{.+}})
|