maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

Use atexit when __cxa_atexit isn't available instead of adding a 

global destructor entry.  For some reason this isn't enabled for
apple-kexts;  it'd be good to have documentation for that.

Based on a patch by Nakamura Takumi!

llvm-svn: 154191
This commit is contained in:
John McCall 2012-04-06 18:21:06 +00:00
parent ee08c53478
commit 76cc43a2a4
5 changed files with 146 additions and 39 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

126
clang/lib/CodeGen/CGDeclCXX.cpp
View File

@ -145,37 +145,109 @@ void CodeGenFunction::EmitCXXGlobalVarDeclInit(const VarDecl &D,
EmitStoreOfScalar(RV.getScalarVal(), DeclPtr, false, Alignment, T);
}
void
CodeGenFunction::EmitCXXGlobalDtorRegistration(llvm::Constant *DtorFn,
llvm::Constant *DeclPtr) {
// Generate a global destructor entry if not using __cxa_atexit.
if (!CGM.getCodeGenOpts().CXAAtExit) {
CGM.AddCXXDtorEntry(DtorFn, DeclPtr);
/// Register a global destructor using __cxa_atexit.
static void emitGlobalDtorWithCXAAtExit(CodeGenFunction &CGF,
llvm::Constant *dtor,
llvm::Constant *addr) {
// We're assuming that the destructor function is something we can
// reasonably call with the default CC. Go ahead and cast it to the
// right prototype.
llvm::Type *dtorTy =
llvm::FunctionType::get(CGF.VoidTy, CGF.Int8PtrTy, false)->getPointerTo();
// extern "C" int __cxa_atexit(void (*f)(void *), void *p, void *d);
llvm::Type *paramTys[] = { dtorTy, CGF.Int8PtrTy, CGF.Int8PtrTy };
llvm::FunctionType *atexitTy =
llvm::FunctionType::get(CGF.IntTy, paramTys, false);
// Fetch the actual function.
llvm::Constant *atexit =
CGF.CGM.CreateRuntimeFunction(atexitTy, "__cxa_atexit");
if (llvm::Function *fn = dyn_cast<llvm::Function>(atexit))
fn->setDoesNotThrow();
// Create a variable that binds the atexit to this shared object.
llvm::Constant *handle =
CGF.CGM.CreateRuntimeVariable(CGF.Int8Ty, "__dso_handle");
llvm::Value *args[] = {
llvm::ConstantExpr::getBitCast(dtor, dtorTy),
llvm::ConstantExpr::getBitCast(addr, CGF.Int8PtrTy),
handle
};
CGF.Builder.CreateCall(atexit, args);
}
static llvm::Function *
CreateGlobalInitOrDestructFunction(CodeGenModule &CGM,
llvm::FunctionType *ty,
const Twine &name);
/// Create a stub function, suitable for being passed to atexit,
/// which passes the given address to the given destructor function.
static llvm::Constant *createAtExitStub(CodeGenModule &CGM,
llvm::Constant *dtor,
llvm::Constant *addr) {
// Get the destructor function type, void(*)(void).
llvm::FunctionType *ty = llvm::FunctionType::get(CGM.VoidTy, false);
llvm::Function *fn =
CreateGlobalInitOrDestructFunction(CGM, ty,
Twine("__dtor_", addr->getName()));
CodeGenFunction CGF(CGM);
CGF.StartFunction(GlobalDecl(), CGM.getContext().VoidTy, fn,
CGM.getTypes().arrangeNullaryFunction(),
FunctionArgList(), SourceLocation());
llvm::CallInst *call = CGF.Builder.CreateCall(dtor, addr);
// Make sure the call and the callee agree on calling convention.
if (llvm::Function *dtorFn =
dyn_cast<llvm::Function>(dtor->stripPointerCasts()))
call->setCallingConv(dtorFn->getCallingConv());
CGF.FinishFunction();
return fn;
}
/// Register a global destructor using atexit.
static void emitGlobalDtorWithAtExit(CodeGenFunction &CGF,
llvm::Constant *dtor,
llvm::Constant *addr) {
// Create a function which calls the destructor.
llvm::Constant *dtorStub = createAtExitStub(CGF.CGM, dtor, addr);
// extern "C" int atexit(void (*f)(void));
llvm::FunctionType *atexitTy =
llvm::FunctionType::get(CGF.IntTy, dtorStub->getType(), false);
llvm::Constant *atexit =
CGF.CGM.CreateRuntimeFunction(atexitTy, "atexit");
if (llvm::Function *atexitFn = dyn_cast<llvm::Function>(atexit))
atexitFn->setDoesNotThrow();
CGF.Builder.CreateCall(atexit, dtorStub);
}
void CodeGenFunction::EmitCXXGlobalDtorRegistration(llvm::Constant *dtor,
llvm::Constant *addr) {
// Use __cxa_atexit if available.
if (CGM.getCodeGenOpts().CXAAtExit) {
emitGlobalDtorWithCXAAtExit(*this, dtor, addr);
return;
}
// Get the destructor function type
llvm::Type *DtorFnTy = llvm::FunctionType::get(VoidTy, Int8PtrTy, false);
DtorFnTy = llvm::PointerType::getUnqual(DtorFnTy);
// In Apple kexts, we want to add a global destructor entry.
// FIXME: shouldn't this be guarded by some variable?
if (CGM.getContext().getLangOpts().AppleKext) {
// Generate a global destructor entry.
CGM.AddCXXDtorEntry(dtor, addr);
}
llvm::Type *Params[] = { DtorFnTy, Int8PtrTy, Int8PtrTy };
// Get the __cxa_atexit function type
// extern "C" int __cxa_atexit ( void (*f)(void *), void *p, void *d );
llvm::FunctionType *AtExitFnTy =
llvm::FunctionType::get(ConvertType(getContext().IntTy), Params, false);
llvm::Constant *AtExitFn = CGM.CreateRuntimeFunction(AtExitFnTy,
"__cxa_atexit");
if (llvm::Function *Fn = dyn_cast<llvm::Function>(AtExitFn))
Fn->setDoesNotThrow();
llvm::Constant *Handle = CGM.CreateRuntimeVariable(Int8PtrTy,
"__dso_handle");
llvm::Value *Args[3] = { llvm::ConstantExpr::getBitCast(DtorFn, DtorFnTy),
llvm::ConstantExpr::getBitCast(DeclPtr, Int8PtrTy),
llvm::ConstantExpr::getBitCast(Handle, Int8PtrTy) };
Builder.CreateCall(AtExitFn, Args);
// Otherwise, we just use atexit.
emitGlobalDtorWithAtExit(*this, dtor, addr);
}
void CodeGenFunction::EmitCXXGuardedInit(const VarDecl &D,

14
clang/test/CodeGenCXX/arm.cpp
View File

@ -20,9 +20,17 @@ public:
// The global dtor needs the right calling conv with -fno-use-cxa-atexit
// rdar://7817590
// Checked at end of file.
bar baz;
// PR9593
// Make sure atexit(3) is used for global dtors.
// CHECK: call [[BAR:%.*]]* @_ZN3barC1Ev(
// CHECK-NEXT: call i32 @atexit(void ()* @__dtor_baz)
// CHECK: define internal void @__dtor_baz()
// CHECK: call [[BAR]]* @_ZN3barD1Ev([[BAR]]* @baz)
// Destructors and constructors must return this.
namespace test1 {
void foo();
@ -357,5 +365,5 @@ namespace test8 {
// CHECK: call void @_ZN5test21CD0Ev(
// CHECK: ret void
// CHECK: @_GLOBAL__D_a()
// CHECK: call %class.bar* @_ZN3barD1Ev(%class.bar* @baz)
// CH_ECK: @_GLOBAL__D_a()
// CH_ECK: call %class.bar* @_ZN3barD1Ev(%class.bar* @baz)

35
clang/test/CodeGenCXX/global-dtor-no-atexit.cpp
View File

@ -3,10 +3,15 @@
// PR7097
// RUN: %clang_cc1 -triple x86_64 %s -fno-use-cxa-atexit -mconstructor-aliases -emit-llvm -o - | FileCheck %s
// CHECK: define internal void @_GLOBAL__D_a()
// CHECK: call void @_ZN1AD1Ev(%class.A* @b)
// CHECK: call void @_ZN1AD1Ev(%class.A* @a)
// CHECK: }
// CHECK: call void @_ZN1AC1Ev([[A:%.*]]* @a)
// CHECK-NEXT: call i32 @atexit(void ()* @__dtor_a)
// CHECK: define internal void @__dtor_a() nounwind
// CHECK: call void @_ZN1AD1Ev([[A]]* @a)
// CHECK: call void @_ZN1AC1Ev([[A]]* @b)
// CHECK-NEXT: call i32 @atexit(void ()* @__dtor_b)
// CHECK: define internal void @__dtor_b() nounwind
// CHECK: call void @_ZN1AD1Ev([[A]]* @b)
class A {
public:
@ -15,3 +20,25 @@ public:
};
A a, b;
// PR9593
// CHECK: define void @_Z4funcv()
// CHECK: call i32 @__cxa_guard_acquire(i64* @_ZGVZ4funcvE2a1)
// CHECK: call void @_ZN1AC1Ev([[A]]* @_ZZ4funcvE2a1)
// CHECK-NEXT: call i32 @atexit(void ()* @__dtor__ZZ4funcvE2a1)
// CHECK-NEXT: call void @__cxa_guard_release(i64* @_ZGVZ4funcvE2a1)
// CHECK: call i32 @__cxa_guard_acquire(i64* @_ZGVZ4funcvE2a2)
// CHECK: call void @_ZN1AC1Ev([[A]]* @_ZZ4funcvE2a2)
// CHECK-NEXT: call i32 @atexit(void ()* @__dtor__ZZ4funcvE2a2)
// CHECK-NEXT: call void @__cxa_guard_release(i64* @_ZGVZ4funcvE2a2)
// CHECK: define internal void @__dtor__ZZ4funcvE2a1() nounwind
// CHECK: call void @_ZN1AD1Ev([[A]]* @_ZZ4funcvE2a1)
// CHECK: define internal void @__dtor__ZZ4funcvE2a2() nounwind
// CHECK: call void @_ZN1AD1Ev([[A]]* @_ZZ4funcvE2a2)
void func() {
static A a1, a2;
}

8
clang/test/CodeGenCXX/global-init.cpp
View File

@ -12,7 +12,7 @@ struct C { void *field; };
struct D { ~D(); };
// CHECK: @__dso_handle = external unnamed_addr global i8*
// CHECK: @__dso_handle = external unnamed_addr global i8
// CHECK: @c = global %struct.C zeroinitializer, align 8
// It's okay if we ever implement the IR-generation optimization to remove this.
@ -24,18 +24,18 @@ struct D { ~D(); };
// CHECK: @_ZN6PR59741bE = global %"struct.PR5974::B"* bitcast (i8* getelementptr (i8* bitcast (%"struct.PR5974::C"* @_ZN6PR59741cE to i8*), i64 4) to %"struct.PR5974::B"*), align 8
// CHECK: call void @_ZN1AC1Ev(%struct.A* @a)
// CHECK: call i32 @__cxa_atexit(void (i8*)* bitcast (void (%struct.A*)* @_ZN1AD1Ev to void (i8*)*), i8* getelementptr inbounds (%struct.A* @a, i32 0, i32 0), i8* bitcast (i8** @__dso_handle to i8*))
// CHECK: call i32 @__cxa_atexit(void (i8*)* bitcast (void (%struct.A*)* @_ZN1AD1Ev to void (i8*)*), i8* getelementptr inbounds (%struct.A* @a, i32 0, i32 0), i8* @__dso_handle)
A a;
// CHECK: call void @_ZN1BC1Ev(%struct.B* @b)
// CHECK: call i32 @__cxa_atexit(void (i8*)* bitcast (void (%struct.B*)* @_ZN1BD1Ev to void (i8*)*), i8* getelementptr inbounds (%struct.B* @b, i32 0, i32 0), i8* bitcast (i8** @__dso_handle to i8*))
// CHECK: call i32 @__cxa_atexit(void (i8*)* bitcast (void (%struct.B*)* @_ZN1BD1Ev to void (i8*)*), i8* getelementptr inbounds (%struct.B* @b, i32 0, i32 0), i8* @__dso_handle)
B b;
// PR6205: this should not require a global initializer
// CHECK-NOT: call void @_ZN1CC1Ev(%struct.C* @c)
C c;
// CHECK: call i32 @__cxa_atexit(void (i8*)* bitcast (void (%struct.D*)* @_ZN1DD1Ev to void (i8*)*), i8* getelementptr inbounds (%struct.D* @d, i32 0, i32 0), i8* bitcast (i8** @__dso_handle to i8*))
// CHECK: call i32 @__cxa_atexit(void (i8*)* bitcast (void (%struct.D*)* @_ZN1DD1Ev to void (i8*)*), i8* getelementptr inbounds (%struct.D* @d, i32 0, i32 0), i8* @__dso_handle)
D d;
// <rdar://problem/7458115>

2
clang/test/CodeGenCXX/static-init.cpp
View File

@ -17,7 +17,7 @@ void f() {
// CHECK: load atomic i8* bitcast (i64* @_ZGVZ1fvE1a to i8*) acquire, align 1
// 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* @_ZZ1fvE1a, i32 0, i32 0), i8* bitcast (i8** @__dso_handle to i8*))
// CHECK: call i32 @__cxa_atexit(void (i8*)* bitcast (void (%struct.A*)* @_ZN1AD1Ev to void (i8*)*), i8* getelementptr inbounds (%struct.A* @_ZZ1fvE1a, i32 0, i32 0), i8* @__dso_handle)
// CHECK: call void @__cxa_guard_release
static A a;
}