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
parent
ee08c53478
commit
76cc43a2a4
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@ -145,37 +145,109 @@ void CodeGenFunction::EmitCXXGlobalVarDeclInit(const VarDecl &D,
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EmitStoreOfScalar(RV.getScalarVal(), DeclPtr, false, Alignment, T);
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}
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void
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CodeGenFunction::EmitCXXGlobalDtorRegistration(llvm::Constant *DtorFn,
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llvm::Constant *DeclPtr) {
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// Generate a global destructor entry if not using __cxa_atexit.
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if (!CGM.getCodeGenOpts().CXAAtExit) {
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CGM.AddCXXDtorEntry(DtorFn, DeclPtr);
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/// Register a global destructor using __cxa_atexit.
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static void emitGlobalDtorWithCXAAtExit(CodeGenFunction &CGF,
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llvm::Constant *dtor,
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llvm::Constant *addr) {
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// We're assuming that the destructor function is something we can
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// reasonably call with the default CC. Go ahead and cast it to the
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// right prototype.
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llvm::Type *dtorTy =
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llvm::FunctionType::get(CGF.VoidTy, CGF.Int8PtrTy, false)->getPointerTo();
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// extern "C" int __cxa_atexit(void (*f)(void *), void *p, void *d);
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llvm::Type *paramTys[] = { dtorTy, CGF.Int8PtrTy, CGF.Int8PtrTy };
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llvm::FunctionType *atexitTy =
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llvm::FunctionType::get(CGF.IntTy, paramTys, false);
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// Fetch the actual function.
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llvm::Constant *atexit =
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CGF.CGM.CreateRuntimeFunction(atexitTy, "__cxa_atexit");
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if (llvm::Function *fn = dyn_cast<llvm::Function>(atexit))
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fn->setDoesNotThrow();
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// Create a variable that binds the atexit to this shared object.
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llvm::Constant *handle =
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CGF.CGM.CreateRuntimeVariable(CGF.Int8Ty, "__dso_handle");
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llvm::Value *args[] = {
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llvm::ConstantExpr::getBitCast(dtor, dtorTy),
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llvm::ConstantExpr::getBitCast(addr, CGF.Int8PtrTy),
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handle
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};
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CGF.Builder.CreateCall(atexit, args);
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}
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static llvm::Function *
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CreateGlobalInitOrDestructFunction(CodeGenModule &CGM,
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llvm::FunctionType *ty,
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const Twine &name);
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/// Create a stub function, suitable for being passed to atexit,
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/// which passes the given address to the given destructor function.
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static llvm::Constant *createAtExitStub(CodeGenModule &CGM,
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llvm::Constant *dtor,
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llvm::Constant *addr) {
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// Get the destructor function type, void(*)(void).
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llvm::FunctionType *ty = llvm::FunctionType::get(CGM.VoidTy, false);
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llvm::Function *fn =
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CreateGlobalInitOrDestructFunction(CGM, ty,
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Twine("__dtor_", addr->getName()));
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CodeGenFunction CGF(CGM);
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CGF.StartFunction(GlobalDecl(), CGM.getContext().VoidTy, fn,
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CGM.getTypes().arrangeNullaryFunction(),
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FunctionArgList(), SourceLocation());
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llvm::CallInst *call = CGF.Builder.CreateCall(dtor, addr);
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// Make sure the call and the callee agree on calling convention.
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if (llvm::Function *dtorFn =
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dyn_cast<llvm::Function>(dtor->stripPointerCasts()))
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call->setCallingConv(dtorFn->getCallingConv());
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CGF.FinishFunction();
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return fn;
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}
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/// Register a global destructor using atexit.
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static void emitGlobalDtorWithAtExit(CodeGenFunction &CGF,
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llvm::Constant *dtor,
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llvm::Constant *addr) {
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// Create a function which calls the destructor.
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llvm::Constant *dtorStub = createAtExitStub(CGF.CGM, dtor, addr);
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// extern "C" int atexit(void (*f)(void));
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llvm::FunctionType *atexitTy =
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llvm::FunctionType::get(CGF.IntTy, dtorStub->getType(), false);
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llvm::Constant *atexit =
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CGF.CGM.CreateRuntimeFunction(atexitTy, "atexit");
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if (llvm::Function *atexitFn = dyn_cast<llvm::Function>(atexit))
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atexitFn->setDoesNotThrow();
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CGF.Builder.CreateCall(atexit, dtorStub);
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}
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void CodeGenFunction::EmitCXXGlobalDtorRegistration(llvm::Constant *dtor,
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llvm::Constant *addr) {
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// Use __cxa_atexit if available.
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if (CGM.getCodeGenOpts().CXAAtExit) {
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emitGlobalDtorWithCXAAtExit(*this, dtor, addr);
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return;
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}
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// Get the destructor function type
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llvm::Type *DtorFnTy = llvm::FunctionType::get(VoidTy, Int8PtrTy, false);
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DtorFnTy = llvm::PointerType::getUnqual(DtorFnTy);
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// In Apple kexts, we want to add a global destructor entry.
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// FIXME: shouldn't this be guarded by some variable?
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if (CGM.getContext().getLangOpts().AppleKext) {
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// Generate a global destructor entry.
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CGM.AddCXXDtorEntry(dtor, addr);
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}
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llvm::Type *Params[] = { DtorFnTy, Int8PtrTy, Int8PtrTy };
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// Get the __cxa_atexit function type
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// extern "C" int __cxa_atexit ( void (*f)(void *), void *p, void *d );
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llvm::FunctionType *AtExitFnTy =
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llvm::FunctionType::get(ConvertType(getContext().IntTy), Params, false);
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llvm::Constant *AtExitFn = CGM.CreateRuntimeFunction(AtExitFnTy,
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"__cxa_atexit");
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if (llvm::Function *Fn = dyn_cast<llvm::Function>(AtExitFn))
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Fn->setDoesNotThrow();
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llvm::Constant *Handle = CGM.CreateRuntimeVariable(Int8PtrTy,
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"__dso_handle");
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llvm::Value *Args[3] = { llvm::ConstantExpr::getBitCast(DtorFn, DtorFnTy),
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llvm::ConstantExpr::getBitCast(DeclPtr, Int8PtrTy),
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llvm::ConstantExpr::getBitCast(Handle, Int8PtrTy) };
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Builder.CreateCall(AtExitFn, Args);
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// Otherwise, we just use atexit.
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emitGlobalDtorWithAtExit(*this, dtor, addr);
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}
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void CodeGenFunction::EmitCXXGuardedInit(const VarDecl &D,
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@ -20,9 +20,17 @@ public:
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// The global dtor needs the right calling conv with -fno-use-cxa-atexit
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// rdar://7817590
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// Checked at end of file.
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bar baz;
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// PR9593
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// Make sure atexit(3) is used for global dtors.
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// CHECK: call [[BAR:%.*]]* @_ZN3barC1Ev(
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// CHECK-NEXT: call i32 @atexit(void ()* @__dtor_baz)
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// CHECK: define internal void @__dtor_baz()
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// CHECK: call [[BAR]]* @_ZN3barD1Ev([[BAR]]* @baz)
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// Destructors and constructors must return this.
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namespace test1 {
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void foo();
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@ -357,5 +365,5 @@ namespace test8 {
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// CHECK: call void @_ZN5test21CD0Ev(
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// CHECK: ret void
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// CHECK: @_GLOBAL__D_a()
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// CHECK: call %class.bar* @_ZN3barD1Ev(%class.bar* @baz)
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// CH_ECK: @_GLOBAL__D_a()
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// CH_ECK: call %class.bar* @_ZN3barD1Ev(%class.bar* @baz)
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@ -3,10 +3,15 @@
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// PR7097
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// RUN: %clang_cc1 -triple x86_64 %s -fno-use-cxa-atexit -mconstructor-aliases -emit-llvm -o - | FileCheck %s
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// CHECK: define internal void @_GLOBAL__D_a()
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// CHECK: call void @_ZN1AD1Ev(%class.A* @b)
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// CHECK: call void @_ZN1AD1Ev(%class.A* @a)
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// CHECK: }
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// CHECK: call void @_ZN1AC1Ev([[A:%.*]]* @a)
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// CHECK-NEXT: call i32 @atexit(void ()* @__dtor_a)
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// CHECK: define internal void @__dtor_a() nounwind
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// CHECK: call void @_ZN1AD1Ev([[A]]* @a)
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// CHECK: call void @_ZN1AC1Ev([[A]]* @b)
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// CHECK-NEXT: call i32 @atexit(void ()* @__dtor_b)
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// CHECK: define internal void @__dtor_b() nounwind
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// CHECK: call void @_ZN1AD1Ev([[A]]* @b)
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class A {
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public:
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@ -15,3 +20,25 @@ public:
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};
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A a, b;
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// PR9593
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// CHECK: define void @_Z4funcv()
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// CHECK: call i32 @__cxa_guard_acquire(i64* @_ZGVZ4funcvE2a1)
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// CHECK: call void @_ZN1AC1Ev([[A]]* @_ZZ4funcvE2a1)
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// CHECK-NEXT: call i32 @atexit(void ()* @__dtor__ZZ4funcvE2a1)
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// CHECK-NEXT: call void @__cxa_guard_release(i64* @_ZGVZ4funcvE2a1)
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// CHECK: call i32 @__cxa_guard_acquire(i64* @_ZGVZ4funcvE2a2)
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// CHECK: call void @_ZN1AC1Ev([[A]]* @_ZZ4funcvE2a2)
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// CHECK-NEXT: call i32 @atexit(void ()* @__dtor__ZZ4funcvE2a2)
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// CHECK-NEXT: call void @__cxa_guard_release(i64* @_ZGVZ4funcvE2a2)
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// CHECK: define internal void @__dtor__ZZ4funcvE2a1() nounwind
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// CHECK: call void @_ZN1AD1Ev([[A]]* @_ZZ4funcvE2a1)
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// CHECK: define internal void @__dtor__ZZ4funcvE2a2() nounwind
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// CHECK: call void @_ZN1AD1Ev([[A]]* @_ZZ4funcvE2a2)
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void func() {
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static A a1, a2;
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}
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@ -12,7 +12,7 @@ struct C { void *field; };
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struct D { ~D(); };
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// CHECK: @__dso_handle = external unnamed_addr global i8*
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// CHECK: @__dso_handle = external unnamed_addr global i8
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// CHECK: @c = global %struct.C zeroinitializer, align 8
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// It's okay if we ever implement the IR-generation optimization to remove this.
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@ -24,18 +24,18 @@ struct D { ~D(); };
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// 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
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// CHECK: call void @_ZN1AC1Ev(%struct.A* @a)
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// 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*))
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// 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)
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A a;
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// CHECK: call void @_ZN1BC1Ev(%struct.B* @b)
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// 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*))
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// 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)
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B b;
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// PR6205: this should not require a global initializer
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// CHECK-NOT: call void @_ZN1CC1Ev(%struct.C* @c)
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C c;
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// 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*))
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// 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)
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D d;
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// <rdar://problem/7458115>
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@ -17,7 +17,7 @@ void f() {
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// CHECK: load atomic i8* bitcast (i64* @_ZGVZ1fvE1a to i8*) acquire, align 1
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// CHECK: call i32 @__cxa_guard_acquire
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// CHECK: call void @_ZN1AC1Ev
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// 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*))
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// 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)
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// CHECK: call void @__cxa_guard_release
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static A a;
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}
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