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-rw-r--r--lib/CodeGen/CGException.cpp131
-rw-r--r--lib/CodeGen/CodeGenFunction.h1
-rw-r--r--test/CXX/except/except.spec/p9-dynamic.cpp2
-rw-r--r--test/CodeGenCXX/arm.cpp4
-rw-r--r--test/CodeGenCXX/destructors.cpp4
-rw-r--r--test/CodeGenCXX/eh.cpp2
-rw-r--r--test/CodeGenCXX/nrvo.cpp2
-rw-r--r--test/CodeGenCXX/threadsafe-statics-exceptions.cpp2
-rw-r--r--test/CodeGenObjC/blocks-2.m2
-rw-r--r--test/CodeGenObjC/unwind-fn.m4
10 files changed, 62 insertions, 92 deletions
diff --git a/lib/CodeGen/CGException.cpp b/lib/CodeGen/CGException.cpp
index 91be321d31..6cb9599e25 100644
--- a/lib/CodeGen/CGException.cpp
+++ b/lib/CodeGen/CGException.cpp
@@ -112,18 +112,11 @@ static llvm::Constant *getUnexpectedFn(CodeGenFunction &CGF) {
return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_call_unexpected");
}
-llvm::Constant *CodeGenFunction::getUnwindResumeFn() {
- const llvm::FunctionType *FTy =
- llvm::FunctionType::get(VoidTy, Int8PtrTy, /*IsVarArgs=*/false);
-
- if (CGM.getLangOptions().SjLjExceptions)
- return CGM.CreateRuntimeFunction(FTy, "_Unwind_SjLj_Resume");
- return CGM.CreateRuntimeFunction(FTy, "_Unwind_Resume");
-}
-
llvm::Constant *CodeGenFunction::getUnwindResumeOrRethrowFn() {
+ const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(getLLVMContext());
const llvm::FunctionType *FTy =
- llvm::FunctionType::get(VoidTy, Int8PtrTy, /*IsVarArgs=*/false);
+ llvm::FunctionType::get(llvm::Type::getVoidTy(getLLVMContext()), Int8PtrTy,
+ /*IsVarArgs=*/false);
if (CGM.getLangOptions().SjLjExceptions)
return CGM.CreateRuntimeFunction(FTy, "_Unwind_SjLj_Resume_or_Rethrow");
@@ -570,59 +563,47 @@ llvm::BasicBlock *CodeGenFunction::getInvokeDestImpl() {
return LP;
}
-// This code contains a hack to work around a design flaw in
-// LLVM's EH IR which breaks semantics after inlining. This same
-// hack is implemented in llvm-gcc.
-//
-// The LLVM EH abstraction is basically a thin veneer over the
-// traditional GCC zero-cost design: for each range of instructions
-// in the function, there is (at most) one "landing pad" with an
-// associated chain of EH actions. A language-specific personality
-// function interprets this chain of actions and (1) decides whether
-// or not to resume execution at the landing pad and (2) if so,
-// provides an integer indicating why it's stopping. In LLVM IR,
-// the association of a landing pad with a range of instructions is
-// achieved via an invoke instruction, the chain of actions becomes
-// the arguments to the @llvm.eh.selector call, and the selector
-// call returns the integer indicator. Other than the required
-// presence of two intrinsic function calls in the landing pad,
-// the IR exactly describes the layout of the output code.
-//
-// A principal advantage of this design is that it is completely
-// language-agnostic; in theory, the LLVM optimizers can treat
-// landing pads neutrally, and targets need only know how to lower
-// the intrinsics to have a functioning exceptions system (assuming
-// that platform exceptions follow something approximately like the
-// GCC design). Unfortunately, landing pads cannot be combined in a
-// language-agnostic way: given selectors A and B, there is no way
-// to make a single landing pad which faithfully represents the
-// semantics of propagating an exception first through A, then
-// through B, without knowing how the personality will interpret the
-// (lowered form of the) selectors. This means that inlining has no
-// choice but to crudely chain invokes (i.e., to ignore invokes in
-// the inlined function, but to turn all unwindable calls into
-// invokes), which is only semantically valid if every unwind stops
-// at every landing pad.
-//
-// Therefore, the invoke-inline hack is to guarantee that every
-// landing pad has a catch-all.
-enum CleanupHackLevel_t {
- /// A level of hack that requires that all landing pads have
- /// catch-alls.
- CHL_MandatoryCatchall,
-
- /// A level of hack that requires that all landing pads handle
- /// cleanups.
- CHL_MandatoryCleanup,
-
- /// No hacks at all; ideal IR generation.
- CHL_Ideal
-};
-const CleanupHackLevel_t CleanupHackLevel = CHL_MandatoryCleanup;
-
llvm::BasicBlock *CodeGenFunction::EmitLandingPad() {
assert(EHStack.requiresLandingPad());
+ // This function contains a hack to work around a design flaw in
+ // LLVM's EH IR which breaks semantics after inlining. This same
+ // hack is implemented in llvm-gcc.
+ //
+ // The LLVM EH abstraction is basically a thin veneer over the
+ // traditional GCC zero-cost design: for each range of instructions
+ // in the function, there is (at most) one "landing pad" with an
+ // associated chain of EH actions. A language-specific personality
+ // function interprets this chain of actions and (1) decides whether
+ // or not to resume execution at the landing pad and (2) if so,
+ // provides an integer indicating why it's stopping. In LLVM IR,
+ // the association of a landing pad with a range of instructions is
+ // achieved via an invoke instruction, the chain of actions becomes
+ // the arguments to the @llvm.eh.selector call, and the selector
+ // call returns the integer indicator. Other than the required
+ // presence of two intrinsic function calls in the landing pad,
+ // the IR exactly describes the layout of the output code.
+ //
+ // A principal advantage of this design is that it is completely
+ // language-agnostic; in theory, the LLVM optimizers can treat
+ // landing pads neutrally, and targets need only know how to lower
+ // the intrinsics to have a functioning exceptions system (assuming
+ // that platform exceptions follow something approximately like the
+ // GCC design). Unfortunately, landing pads cannot be combined in a
+ // language-agnostic way: given selectors A and B, there is no way
+ // to make a single landing pad which faithfully represents the
+ // semantics of propagating an exception first through A, then
+ // through B, without knowing how the personality will interpret the
+ // (lowered form of the) selectors. This means that inlining has no
+ // choice but to crudely chain invokes (i.e., to ignore invokes in
+ // the inlined function, but to turn all unwindable calls into
+ // invokes), which is only semantically valid if every unwind stops
+ // at every landing pad.
+ //
+ // Therefore, the invoke-inline hack is to guarantee that every
+ // landing pad has a catch-all.
+ const bool UseInvokeInlineHack = true;
+
for (EHScopeStack::iterator ir = EHStack.begin(); ; ) {
assert(ir != EHStack.end() &&
"stack requiring landing pad is nothing but non-EH scopes?");
@@ -755,23 +736,16 @@ llvm::BasicBlock *CodeGenFunction::EmitLandingPad() {
EHSelector.append(EHFilters.begin(), EHFilters.end());
// Also check whether we need a cleanup.
- if (CleanupHackLevel == CHL_MandatoryCatchall || HasEHCleanup)
- EHSelector.push_back(CleanupHackLevel == CHL_MandatoryCatchall
+ if (UseInvokeInlineHack || HasEHCleanup)
+ EHSelector.push_back(UseInvokeInlineHack
? getCatchAllValue(*this)
: getCleanupValue(*this));
// Otherwise, signal that we at least have cleanups.
- } else if (CleanupHackLevel == CHL_MandatoryCatchall || HasEHCleanup) {
- EHSelector.push_back(CleanupHackLevel == CHL_MandatoryCatchall
+ } else if (UseInvokeInlineHack || HasEHCleanup) {
+ EHSelector.push_back(UseInvokeInlineHack
? getCatchAllValue(*this)
: getCleanupValue(*this));
-
- // At the MandatoryCleanup hack level, we don't need to actually
- // spuriously tell the unwinder that we have cleanups, but we do
- // need to always be prepared to handle cleanups.
- } else if (CleanupHackLevel == CHL_MandatoryCleanup) {
- // Just don't decrement LastToEmitInLoop.
-
} else {
assert(LastToEmitInLoop > 2);
LastToEmitInLoop--;
@@ -859,7 +833,7 @@ llvm::BasicBlock *CodeGenFunction::EmitLandingPad() {
// If there was a cleanup, we'll need to actually check whether we
// landed here because the filter triggered.
- if (CleanupHackLevel != CHL_Ideal || HasEHCleanup) {
+ if (UseInvokeInlineHack || HasEHCleanup) {
llvm::BasicBlock *RethrowBB = createBasicBlock("cleanup");
llvm::BasicBlock *UnexpectedBB = createBasicBlock("ehspec.unexpected");
@@ -869,11 +843,10 @@ llvm::BasicBlock *CodeGenFunction::EmitLandingPad() {
Builder.CreateCondBr(FailsFilter, UnexpectedBB, RethrowBB);
// The rethrow block is where we land if this was a cleanup.
+ // TODO: can this be _Unwind_Resume if the InvokeInlineHack is off?
EmitBlock(RethrowBB);
- llvm::Constant *RethrowFn =
- CleanupHackLevel == CHL_MandatoryCatchall ? getUnwindResumeOrRethrowFn()
- : getUnwindResumeFn();
- Builder.CreateCall(RethrowFn, Builder.CreateLoad(getExceptionSlot()))
+ Builder.CreateCall(getUnwindResumeOrRethrowFn(),
+ Builder.CreateLoad(getExceptionSlot()))
->setDoesNotReturn();
Builder.CreateUnreachable();
@@ -890,7 +863,7 @@ llvm::BasicBlock *CodeGenFunction::EmitLandingPad() {
Builder.CreateUnreachable();
// ...or a normal catch handler...
- } else if (CleanupHackLevel == CHL_Ideal && !HasEHCleanup) {
+ } else if (!UseInvokeInlineHack && !HasEHCleanup) {
llvm::Value *Type = EHSelector.back();
EmitBranchThroughEHCleanup(EHHandlers[Type]);
@@ -1471,9 +1444,7 @@ CodeGenFunction::UnwindDest CodeGenFunction::getRethrowDest() {
if (!RethrowName.empty())
RethrowFn = getCatchallRethrowFn(*this, RethrowName);
else
- RethrowFn = (CleanupHackLevel == CHL_MandatoryCatchall
- ? getUnwindResumeOrRethrowFn()
- : getUnwindResumeFn());
+ RethrowFn = getUnwindResumeOrRethrowFn();
Builder.CreateCall(RethrowFn, Builder.CreateLoad(getExceptionSlot()))
->setDoesNotReturn();
diff --git a/lib/CodeGen/CodeGenFunction.h b/lib/CodeGen/CodeGenFunction.h
index 8613f05e92..9aa7903ab7 100644
--- a/lib/CodeGen/CodeGenFunction.h
+++ b/lib/CodeGen/CodeGenFunction.h
@@ -1705,7 +1705,6 @@ public:
void EmitObjCAtThrowStmt(const ObjCAtThrowStmt &S);
void EmitObjCAtSynchronizedStmt(const ObjCAtSynchronizedStmt &S);
- llvm::Constant *getUnwindResumeFn();
llvm::Constant *getUnwindResumeOrRethrowFn();
void EnterCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock = false);
void ExitCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock = false);
diff --git a/test/CXX/except/except.spec/p9-dynamic.cpp b/test/CXX/except/except.spec/p9-dynamic.cpp
index 3f496f25c9..490d2fa21f 100644
--- a/test/CXX/except/except.spec/p9-dynamic.cpp
+++ b/test/CXX/except/except.spec/p9-dynamic.cpp
@@ -7,5 +7,5 @@ void target() throw(int)
// CHECK: invoke void @_Z8externalv()
external();
}
-// CHECK: call i32 (i8*, i8*, ...)* @llvm.eh.selector({{.*}} i8* bitcast (i8** @_ZTIi to i8*)) nounwind
+// CHECK: call i32 (i8*, i8*, ...)* @llvm.eh.selector({{.*}} i8* bitcast (i8** @_ZTIi to i8*), i8* null) nounwind
// CHECK: call void @__cxa_call_unexpected
diff --git a/test/CodeGenCXX/arm.cpp b/test/CodeGenCXX/arm.cpp
index a3333171c1..f56b1552ce 100644
--- a/test/CodeGenCXX/arm.cpp
+++ b/test/CodeGenCXX/arm.cpp
@@ -310,7 +310,7 @@ namespace test7 {
// CHECK: call i8* @llvm.eh.exception()
// CHECK: call void @__cxa_guard_abort(i32* @_ZGVZN5test74testEvE1x)
- // CHECK: call void @_Unwind_Resume(
+ // CHECK: call void @_Unwind_Resume_or_Rethrow
}
}
@@ -349,7 +349,7 @@ namespace test8 {
// CHECK: call i8* @llvm.eh.exception()
// CHECK: call void @__cxa_guard_abort(i32* @_ZGVZN5test84testEvE1x)
- // CHECK: call void @_Unwind_Resume(
+ // CHECK: call void @_Unwind_Resume_or_Rethrow
}
}
diff --git a/test/CodeGenCXX/destructors.cpp b/test/CodeGenCXX/destructors.cpp
index bc32d7d743..353b61061a 100644
--- a/test/CodeGenCXX/destructors.cpp
+++ b/test/CodeGenCXX/destructors.cpp
@@ -334,7 +334,7 @@ namespace test7 {
// CHECK: ret void
// CHECK: call i8* @llvm.eh.exception(
// CHECK: call void @_ZdlPv({{.*}}) nounwind
- // CHECK: call void @_Unwind_Resume(
+ // CHECK: call void @_Unwind_Resume_or_Rethrow
// Checked at top of file:
// @_ZN5test312_GLOBAL__N_11DD1Ev = alias internal {{.*}} @_ZN5test312_GLOBAL__N_11DD2Ev
@@ -364,7 +364,7 @@ namespace test7 {
// CHECK: ret void
// CHECK: call i8* @llvm.eh.exception()
// CHECK: call void @_ZdlPv({{.*}}) nounwind
- // CHECK: call void @_Unwind_Resume(
+ // CHECK: call void @_Unwind_Resume_or_Rethrow(
// CHECK: define internal void @_ZThn8_N5test312_GLOBAL__N_11CD1Ev(
// CHECK: getelementptr inbounds i8* {{.*}}, i64 -8
diff --git a/test/CodeGenCXX/eh.cpp b/test/CodeGenCXX/eh.cpp
index 250d47edd2..88c32724b8 100644
--- a/test/CodeGenCXX/eh.cpp
+++ b/test/CodeGenCXX/eh.cpp
@@ -190,7 +190,7 @@ namespace test9 {
// landing pad from first call to invoke
// CHECK: call i8* @llvm.eh.exception
- // CHECK: call i32 (i8*, i8*, ...)* @llvm.eh.selector(i8* {{.*}}, i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*), i8* bitcast (i8** @_ZTIi to i8*))
+ // CHECK: call i32 (i8*, i8*, ...)* @llvm.eh.selector(i8* {{.*}}, i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*), i8* bitcast (i8** @_ZTIi to i8*), i8* null)
}
// __cxa_end_catch can throw for some kinds of caught exceptions.
diff --git a/test/CodeGenCXX/nrvo.cpp b/test/CodeGenCXX/nrvo.cpp
index 3104f937f1..ad6fa4f744 100644
--- a/test/CodeGenCXX/nrvo.cpp
+++ b/test/CodeGenCXX/nrvo.cpp
@@ -95,7 +95,7 @@ X test2(bool B) {
// %invoke.cont17: rethrow block for %eh.cleanup.
// This really should be elsewhere in the function.
- // CHECK-EH: call void @_Unwind_Resume(
+ // CHECK-EH: call void @_Unwind_Resume_or_Rethrow
// CHECK-EH-NEXT: unreachable
// %terminate.lpad: terminate landing pad.
diff --git a/test/CodeGenCXX/threadsafe-statics-exceptions.cpp b/test/CodeGenCXX/threadsafe-statics-exceptions.cpp
index 06ebe0a71b..0bd810eeca 100644
--- a/test/CodeGenCXX/threadsafe-statics-exceptions.cpp
+++ b/test/CodeGenCXX/threadsafe-statics-exceptions.cpp
@@ -24,6 +24,6 @@ void f() {
// CHECK: call i8* @llvm.eh.exception()
// CHECK: call i32 (i8*, i8*, ...)* @llvm.eh.selector
// CHECK: call void @__cxa_guard_abort(i64* @_ZGVZ1fvE1x)
- // CHECK: call void @_Unwind_Resume(
+ // CHECK: call void @_Unwind_Resume_or_Rethrow
// CHECK: unreachable
}
diff --git a/test/CodeGenObjC/blocks-2.m b/test/CodeGenObjC/blocks-2.m
index 1f1c272fbf..38b8635609 100644
--- a/test/CodeGenObjC/blocks-2.m
+++ b/test/CodeGenObjC/blocks-2.m
@@ -33,5 +33,5 @@ void test1() {
// CHECK: call i8* @llvm.eh.exception()
// CHECK: [[T1:%.*]] = bitcast [[N_T]]* [[N]] to i8*
// CHECK-NEXT: call void @_Block_object_dispose(i8* [[T1]], i32 8)
- // CHECK: call void @_Unwind_Resume(
+ // CHECK: call void @_Unwind_Resume_or_Rethrow(
}
diff --git a/test/CodeGenObjC/unwind-fn.m b/test/CodeGenObjC/unwind-fn.m
index 8d13c98969..5e4a7a5863 100644
--- a/test/CodeGenObjC/unwind-fn.m
+++ b/test/CodeGenObjC/unwind-fn.m
@@ -1,8 +1,8 @@
// RUN: %clang_cc1 -fobjc-nonfragile-abi -emit-llvm -fexceptions -fobjc-exceptions -o - %s | FileCheck --check-prefix=DEFAULT_EH %s
// RUN: %clang_cc1 -fsjlj-exceptions -fobjc-nonfragile-abi -fexceptions -fobjc-exceptions -emit-llvm -o - %s | FileCheck --check-prefix=SJLJ_EH %s
-// DEFAULT_EH: declare void @_Unwind_Resume(i8*)
-// SJLJ_EH: declare void @_Unwind_SjLj_Resume(i8*)
+// DEFAULT_EH: declare void @_Unwind_Resume_or_Rethrow(i8*)
+// SJLJ_EH: declare void @_Unwind_SjLj_Resume_or_Rethrow(i8*)
void f1(), f2();
void f0() {
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2025-07-02 23:00:42 +0000